From c2758baa9798bf75d79a9aad8792edb8b694373e Mon Sep 17 00:00:00 2001
From: Dave Marchevsky <davemarchevsky@fb.com>
Date: Fri, 17 Sep 2021 11:29:06 -0700
Subject: libbpf: Modify bpf_printk to choose helper based on arg count

Instead of being a thin wrapper which calls into bpf_trace_printk,
libbpf's bpf_printk convenience macro now chooses between
bpf_trace_printk and bpf_trace_vprintk. If the arg count (excluding
format string) is >3, use bpf_trace_vprintk, otherwise use the older
helper.

The motivation behind this added complexity - instead of migrating
entirely to bpf_trace_vprintk - is to maintain good developer experience
for users compiling against new libbpf but running on older kernels.
Users who are passing <=3 args to bpf_printk will see no change in their
bytecode.

__bpf_vprintk functions similarly to BPF_SEQ_PRINTF and BPF_SNPRINTF
macros elsewhere in the file - it allows use of bpf_trace_vprintk
without manual conversion of varargs to u64 array. Previous
implementation of bpf_printk macro is moved to __bpf_printk for use by
the new implementation.

This does change behavior of bpf_printk calls with >3 args in the "new
libbpf, old kernels" scenario. Before this patch, attempting to use 4
args to bpf_printk results in a compile-time error. After this patch,
using bpf_printk with 4 args results in a trace_vprintk helper call
being emitted and a load-time failure on older kernels.

Signed-off-by: Dave Marchevsky <davemarchevsky@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20210917182911.2426606-5-davemarchevsky@fb.com
---
 tools/lib/bpf/bpf_helpers.h | 45 +++++++++++++++++++++++++++++++++++++--------
 1 file changed, 37 insertions(+), 8 deletions(-)

(limited to 'tools/lib/bpf')

diff --git a/tools/lib/bpf/bpf_helpers.h b/tools/lib/bpf/bpf_helpers.h
index b9987c3efa3c..55a308796625 100644
--- a/tools/lib/bpf/bpf_helpers.h
+++ b/tools/lib/bpf/bpf_helpers.h
@@ -14,14 +14,6 @@
 #define __type(name, val) typeof(val) *name
 #define __array(name, val) typeof(val) *name[]
 
-/* Helper macro to print out debug messages */
-#define bpf_printk(fmt, ...)				\
-({							\
-	char ____fmt[] = fmt;				\
-	bpf_trace_printk(____fmt, sizeof(____fmt),	\
-			 ##__VA_ARGS__);		\
-})
-
 /*
  * Helper macro to place programs, maps, license in
  * different sections in elf_bpf file. Section names
@@ -224,4 +216,41 @@ enum libbpf_tristate {
 		     ___param, sizeof(___param));		\
 })
 
+#define __bpf_printk(fmt, ...)				\
+({							\
+	char ____fmt[] = fmt;				\
+	bpf_trace_printk(____fmt, sizeof(____fmt),	\
+			 ##__VA_ARGS__);		\
+})
+
+/*
+ * __bpf_vprintk wraps the bpf_trace_vprintk helper with variadic arguments
+ * instead of an array of u64.
+ */
+#define __bpf_vprintk(fmt, args...)				\
+({								\
+	static const char ___fmt[] = fmt;			\
+	unsigned long long ___param[___bpf_narg(args)];		\
+								\
+	_Pragma("GCC diagnostic push")				\
+	_Pragma("GCC diagnostic ignored \"-Wint-conversion\"")	\
+	___bpf_fill(___param, args);				\
+	_Pragma("GCC diagnostic pop")				\
+								\
+	bpf_trace_vprintk(___fmt, sizeof(___fmt),		\
+			  ___param, sizeof(___param));		\
+})
+
+/* Use __bpf_printk when bpf_printk call has 3 or fewer fmt args
+ * Otherwise use __bpf_vprintk
+ */
+#define ___bpf_pick_printk(...) \
+	___bpf_nth(_, ##__VA_ARGS__, __bpf_vprintk, __bpf_vprintk, __bpf_vprintk,	\
+		   __bpf_vprintk, __bpf_vprintk, __bpf_vprintk, __bpf_vprintk,		\
+		   __bpf_vprintk, __bpf_vprintk, __bpf_printk /*3*/, __bpf_printk /*2*/,\
+		   __bpf_printk /*1*/, __bpf_printk /*0*/)
+
+/* Helper macro to print out debug messages */
+#define bpf_printk(fmt, args...) ___bpf_pick_printk(args)(fmt, ##args)
+
 #endif
-- 
cgit v1.2.3


From 6c66b0e7c91a1320c1b85ad8150bdd534eb4ddae Mon Sep 17 00:00:00 2001
From: Dave Marchevsky <davemarchevsky@fb.com>
Date: Fri, 17 Sep 2021 11:29:07 -0700
Subject: libbpf: Use static const fmt string in __bpf_printk

The __bpf_printk convenience macro was using a 'char' fmt string holder
as it predates support for globals in libbpf. Move to more efficient
'static const char', but provide a fallback to the old way via
BPF_NO_GLOBAL_DATA so users on old kernels can still use the macro.

Signed-off-by: Dave Marchevsky <davemarchevsky@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20210917182911.2426606-6-davemarchevsky@fb.com
---
 tools/lib/bpf/bpf_helpers.h | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

(limited to 'tools/lib/bpf')

diff --git a/tools/lib/bpf/bpf_helpers.h b/tools/lib/bpf/bpf_helpers.h
index 55a308796625..963b1060d944 100644
--- a/tools/lib/bpf/bpf_helpers.h
+++ b/tools/lib/bpf/bpf_helpers.h
@@ -216,9 +216,15 @@ enum libbpf_tristate {
 		     ___param, sizeof(___param));		\
 })
 
+#ifdef BPF_NO_GLOBAL_DATA
+#define BPF_PRINTK_FMT_MOD
+#else
+#define BPF_PRINTK_FMT_MOD static const
+#endif
+
 #define __bpf_printk(fmt, ...)				\
 ({							\
-	char ____fmt[] = fmt;				\
+	BPF_PRINTK_FMT_MOD char ____fmt[] = fmt;	\
 	bpf_trace_printk(____fmt, sizeof(____fmt),	\
 			 ##__VA_ARGS__);		\
 })
-- 
cgit v1.2.3


From 97c140d94e2e5f050d5f418317cc34f83da3d0f5 Mon Sep 17 00:00:00 2001
From: Grant Seltzer <grantseltzer@gmail.com>
Date: Fri, 17 Sep 2021 23:14:58 -0400
Subject: libbpf: Add doc comments in libbpf.h

This adds comments above functions in libbpf.h which document
their uses. These comments are of a format that doxygen and sphinx
can pick up and render. These are rendered by libbpf.readthedocs.org

These doc comments are for:
- bpf_object__find_map_by_name()
- bpf_map__fd()
- bpf_map__is_internal()
- libbpf_get_error()
- libbpf_num_possible_cpus()

Signed-off-by: Grant Seltzer <grantseltzer@gmail.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20210918031457.36204-1-grantseltzer@gmail.com
---
 tools/lib/bpf/libbpf.h | 65 +++++++++++++++++++++++++++++++++++++++++++-------
 1 file changed, 57 insertions(+), 8 deletions(-)

(limited to 'tools/lib/bpf')

diff --git a/tools/lib/bpf/libbpf.h b/tools/lib/bpf/libbpf.h
index c90e3d79e72c..d0bedd673273 100644
--- a/tools/lib/bpf/libbpf.h
+++ b/tools/lib/bpf/libbpf.h
@@ -481,9 +481,13 @@ struct bpf_map_def {
 	unsigned int map_flags;
 };
 
-/*
- * The 'struct bpf_map' in include/linux/bpf.h is internal to the kernel,
- * so no need to worry about a name clash.
+/**
+ * @brief **bpf_object__find_map_by_name()** returns BPF map of
+ * the given name, if it exists within the passed BPF object
+ * @param obj BPF object
+ * @param name name of the BPF map
+ * @return BPF map instance, if such map exists within the BPF object;
+ * or NULL otherwise.
  */
 LIBBPF_API struct bpf_map *
 bpf_object__find_map_by_name(const struct bpf_object *obj, const char *name);
@@ -509,7 +513,12 @@ bpf_map__next(const struct bpf_map *map, const struct bpf_object *obj);
 LIBBPF_API struct bpf_map *
 bpf_map__prev(const struct bpf_map *map, const struct bpf_object *obj);
 
-/* get/set map FD */
+/**
+ * @brief **bpf_map__fd()** gets the file descriptor of the passed
+ * BPF map
+ * @param map the BPF map instance
+ * @return the file descriptor; or -EINVAL in case of an error
+ */
 LIBBPF_API int bpf_map__fd(const struct bpf_map *map);
 LIBBPF_API int bpf_map__reuse_fd(struct bpf_map *map, int fd);
 /* get map definition */
@@ -550,6 +559,14 @@ LIBBPF_API int bpf_map__set_initial_value(struct bpf_map *map,
 					  const void *data, size_t size);
 LIBBPF_API const void *bpf_map__initial_value(struct bpf_map *map, size_t *psize);
 LIBBPF_API bool bpf_map__is_offload_neutral(const struct bpf_map *map);
+
+/**
+ * @brief **bpf_map__is_internal()** tells the caller whether or not the
+ * passed map is a special map created by libbpf automatically for things like
+ * global variables, __ksym externs, Kconfig values, etc
+ * @param map the bpf_map
+ * @return true, if the map is an internal map; false, otherwise
+ */
 LIBBPF_API bool bpf_map__is_internal(const struct bpf_map *map);
 LIBBPF_API int bpf_map__set_pin_path(struct bpf_map *map, const char *path);
 LIBBPF_API const char *bpf_map__get_pin_path(const struct bpf_map *map);
@@ -561,6 +578,38 @@ LIBBPF_API int bpf_map__unpin(struct bpf_map *map, const char *path);
 LIBBPF_API int bpf_map__set_inner_map_fd(struct bpf_map *map, int fd);
 LIBBPF_API struct bpf_map *bpf_map__inner_map(struct bpf_map *map);
 
+/**
+ * @brief **libbpf_get_error()** extracts the error code from the passed
+ * pointer
+ * @param ptr pointer returned from libbpf API function
+ * @return error code; or 0 if no error occured
+ *
+ * Many libbpf API functions which return pointers have logic to encode error
+ * codes as pointers, and do not return NULL. Meaning **libbpf_get_error()**
+ * should be used on the return value from these functions immediately after
+ * calling the API function, with no intervening calls that could clobber the
+ * `errno` variable. Consult the individual functions documentation to verify
+ * if this logic applies should be used.
+ *
+ * For these API functions, if `libbpf_set_strict_mode(LIBBPF_STRICT_CLEAN_PTRS)`
+ * is enabled, NULL is returned on error instead.
+ *
+ * If ptr is NULL, then errno should be already set by the failing
+ * API, because libbpf never returns NULL on success and it now always
+ * sets errno on error.
+ *
+ * Example usage:
+ *
+ *   struct perf_buffer *pb;
+ *
+ *   pb = perf_buffer__new(bpf_map__fd(obj->maps.events), PERF_BUFFER_PAGES, &opts);
+ *   err = libbpf_get_error(pb);
+ *   if (err) {
+ *	  pb = NULL;
+ *	  fprintf(stderr, "failed to open perf buffer: %d\n", err);
+ *	  goto cleanup;
+ *   }
+ */
 LIBBPF_API long libbpf_get_error(const void *ptr);
 
 struct bpf_prog_load_attr {
@@ -825,9 +874,10 @@ bpf_program__bpil_addr_to_offs(struct bpf_prog_info_linear *info_linear);
 LIBBPF_API void
 bpf_program__bpil_offs_to_addr(struct bpf_prog_info_linear *info_linear);
 
-/*
- * A helper function to get the number of possible CPUs before looking up
- * per-CPU maps. Negative errno is returned on failure.
+/**
+ * @brief **libbpf_num_possible_cpus()** is a helper function to get the
+ * number of possible CPUs that the host kernel supports and expects.
+ * @return number of possible CPUs; or error code on failure
  *
  * Example usage:
  *
@@ -837,7 +887,6 @@ bpf_program__bpil_offs_to_addr(struct bpf_prog_info_linear *info_linear);
  *     }
  *     long values[ncpus];
  *     bpf_map_lookup_elem(per_cpu_map_fd, key, values);
- *
  */
 LIBBPF_API int libbpf_num_possible_cpus(void);
 
-- 
cgit v1.2.3


From 303a257223a3bbd7cc6ccc2b7777179c8d9f3989 Mon Sep 17 00:00:00 2001
From: Andrii Nakryiko <andrii@kernel.org>
Date: Tue, 21 Sep 2021 14:00:33 -0700
Subject: libbpf: Fix memory leak in legacy kprobe attach logic

In some error scenarios legacy_probe string won't be free()'d. Fix this.
This was reported by Coverity static analysis.

Fixes: ca304b40c20d ("libbpf: Introduce legacy kprobe events support")
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20210921210036.1545557-2-andrii@kernel.org
---
 tools/lib/bpf/libbpf.c | 10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)

(limited to 'tools/lib/bpf')

diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index da65a1666a5e..6d2f12db6034 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -9365,10 +9365,11 @@ bpf_program__attach_kprobe_opts(const struct bpf_program *prog,
 						    offset, -1 /* pid */);
 	}
 	if (pfd < 0) {
+		err = pfd;
 		pr_warn("prog '%s': failed to create %s '%s' perf event: %s\n",
 			prog->name, retprobe ? "kretprobe" : "kprobe", func_name,
-			libbpf_strerror_r(pfd, errmsg, sizeof(errmsg)));
-		return libbpf_err_ptr(pfd);
+			libbpf_strerror_r(err, errmsg, sizeof(errmsg)));
+		goto err_out;
 	}
 	link = bpf_program__attach_perf_event_opts(prog, pfd, &pe_opts);
 	err = libbpf_get_error(link);
@@ -9377,7 +9378,7 @@ bpf_program__attach_kprobe_opts(const struct bpf_program *prog,
 		pr_warn("prog '%s': failed to attach to %s '%s': %s\n",
 			prog->name, retprobe ? "kretprobe" : "kprobe", func_name,
 			libbpf_strerror_r(err, errmsg, sizeof(errmsg)));
-		return libbpf_err_ptr(err);
+		goto err_out;
 	}
 	if (legacy) {
 		struct bpf_link_perf *perf_link = container_of(link, struct bpf_link_perf, link);
@@ -9387,6 +9388,9 @@ bpf_program__attach_kprobe_opts(const struct bpf_program *prog,
 	}
 
 	return link;
+err_out:
+	free(legacy_probe);
+	return libbpf_err_ptr(err);
 }
 
 struct bpf_link *bpf_program__attach_kprobe(const struct bpf_program *prog,
-- 
cgit v1.2.3


From 46ed5fc33db966aa1a46e8ae9d96b08b756a2546 Mon Sep 17 00:00:00 2001
From: Andrii Nakryiko <andrii@kernel.org>
Date: Tue, 21 Sep 2021 14:00:35 -0700
Subject: libbpf: Refactor and simplify legacy kprobe code

Refactor legacy kprobe handling code to follow the same logic as uprobe
legacy logic added in the next patchs:
  - add append_to_file() helper that makes it simpler to work with
    tracefs file-based interface for creating and deleting probes;
  - move out probe/event name generation outside of the code that
    adds/removes it, which simplifies bookkeeping significantly;
  - change the probe name format to start with "libbpf_" prefix and
    include offset within kernel function;
  - switch 'unsigned long' to 'size_t' for specifying kprobe offsets,
    which is consistent with how uprobes define that, simplifies
    printf()-ing internally, and also avoids unnecessary complications on
    architectures where sizeof(long) != sizeof(void *).

This patch also implicitly fixes the problem with invalid open() error
handling present in poke_kprobe_events(), which (the function) this
patch removes.

Fixes: ca304b40c20d ("libbpf: Introduce legacy kprobe events support")
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20210921210036.1545557-4-andrii@kernel.org
---
 tools/lib/bpf/libbpf.c | 159 +++++++++++++++++++++++++++----------------------
 tools/lib/bpf/libbpf.h |   2 +-
 2 files changed, 88 insertions(+), 73 deletions(-)

(limited to 'tools/lib/bpf')

diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index 6d2f12db6034..aa842f0721cb 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -9011,59 +9011,17 @@ int bpf_link__unpin(struct bpf_link *link)
 	return 0;
 }
 
-static int poke_kprobe_events(bool add, const char *name, bool retprobe, uint64_t offset)
-{
-	int fd, ret = 0;
-	pid_t p = getpid();
-	char cmd[260], probename[128], probefunc[128];
-	const char *file = "/sys/kernel/debug/tracing/kprobe_events";
-
-	if (retprobe)
-		snprintf(probename, sizeof(probename), "kretprobes/%s_libbpf_%u", name, p);
-	else
-		snprintf(probename, sizeof(probename), "kprobes/%s_libbpf_%u", name, p);
-
-	if (offset)
-		snprintf(probefunc, sizeof(probefunc), "%s+%zu", name, (size_t)offset);
-
-	if (add) {
-		snprintf(cmd, sizeof(cmd), "%c:%s %s",
-			 retprobe ? 'r' : 'p',
-			 probename,
-			 offset ? probefunc : name);
-	} else {
-		snprintf(cmd, sizeof(cmd), "-:%s", probename);
-	}
-
-	fd = open(file, O_WRONLY | O_APPEND, 0);
-	if (!fd)
-		return -errno;
-	ret = write(fd, cmd, strlen(cmd));
-	if (ret < 0)
-		ret = -errno;
-	close(fd);
-
-	return ret;
-}
-
-static inline int add_kprobe_event_legacy(const char *name, bool retprobe, uint64_t offset)
-{
-	return poke_kprobe_events(true, name, retprobe, offset);
-}
-
-static inline int remove_kprobe_event_legacy(const char *name, bool retprobe)
-{
-	return poke_kprobe_events(false, name, retprobe, 0);
-}
-
 struct bpf_link_perf {
 	struct bpf_link link;
 	int perf_event_fd;
 	/* legacy kprobe support: keep track of probe identifier and type */
 	char *legacy_probe_name;
+	bool legacy_is_kprobe;
 	bool legacy_is_retprobe;
 };
 
+static int remove_kprobe_event_legacy(const char *probe_name, bool retprobe);
+
 static int bpf_link_perf_detach(struct bpf_link *link)
 {
 	struct bpf_link_perf *perf_link = container_of(link, struct bpf_link_perf, link);
@@ -9077,9 +9035,12 @@ static int bpf_link_perf_detach(struct bpf_link *link)
 	close(link->fd);
 
 	/* legacy kprobe needs to be removed after perf event fd closure */
-	if (perf_link->legacy_probe_name)
-		err = remove_kprobe_event_legacy(perf_link->legacy_probe_name,
-						 perf_link->legacy_is_retprobe);
+	if (perf_link->legacy_probe_name) {
+		if (perf_link->legacy_is_kprobe) {
+			err = remove_kprobe_event_legacy(perf_link->legacy_probe_name,
+							 perf_link->legacy_is_retprobe);
+		}
+	}
 
 	return err;
 }
@@ -9202,18 +9163,6 @@ static int parse_uint_from_file(const char *file, const char *fmt)
 	return ret;
 }
 
-static int determine_kprobe_perf_type_legacy(const char *func_name, bool is_retprobe)
-{
-	char file[192];
-
-	snprintf(file, sizeof(file),
-		 "/sys/kernel/debug/tracing/events/%s/%s_libbpf_%d/id",
-		 is_retprobe ? "kretprobes" : "kprobes",
-		 func_name, getpid());
-
-	return parse_uint_from_file(file, "%d\n");
-}
-
 static int determine_kprobe_perf_type(void)
 {
 	const char *file = "/sys/bus/event_source/devices/kprobe/type";
@@ -9296,21 +9245,79 @@ static int perf_event_open_probe(bool uprobe, bool retprobe, const char *name,
 	return pfd;
 }
 
-static int perf_event_kprobe_open_legacy(bool retprobe, const char *name, uint64_t offset, int pid)
+static int append_to_file(const char *file, const char *fmt, ...)
+{
+	int fd, n, err = 0;
+	va_list ap;
+
+	fd = open(file, O_WRONLY | O_APPEND, 0);
+	if (fd < 0)
+		return -errno;
+
+	va_start(ap, fmt);
+	n = vdprintf(fd, fmt, ap);
+	va_end(ap);
+
+	if (n < 0)
+		err = -errno;
+
+	close(fd);
+	return err;
+}
+
+static void gen_kprobe_legacy_event_name(char *buf, size_t buf_sz,
+					 const char *kfunc_name, size_t offset)
+{
+	snprintf(buf, buf_sz, "libbpf_%u_%s_0x%zx", getpid(), kfunc_name, offset);
+}
+
+static int add_kprobe_event_legacy(const char *probe_name, bool retprobe,
+				   const char *kfunc_name, size_t offset)
+{
+	const char *file = "/sys/kernel/debug/tracing/kprobe_events";
+
+	return append_to_file(file, "%c:%s/%s %s+0x%zx",
+			      retprobe ? 'r' : 'p',
+			      retprobe ? "kretprobes" : "kprobes",
+			      probe_name, kfunc_name, offset);
+}
+
+static int remove_kprobe_event_legacy(const char *probe_name, bool retprobe)
+{
+	const char *file = "/sys/kernel/debug/tracing/kprobe_events";
+
+	return append_to_file(file, "-:%s/%s", retprobe ? "kretprobes" : "kprobes", probe_name);
+}
+
+static int determine_kprobe_perf_type_legacy(const char *probe_name, bool retprobe)
+{
+	char file[256];
+
+	snprintf(file, sizeof(file),
+		 "/sys/kernel/debug/tracing/events/%s/%s/id",
+		 retprobe ? "kretprobes" : "kprobes", probe_name);
+
+	return parse_uint_from_file(file, "%d\n");
+}
+
+static int perf_event_kprobe_open_legacy(const char *probe_name, bool retprobe,
+					 const char *kfunc_name, size_t offset, int pid)
 {
 	struct perf_event_attr attr = {};
 	char errmsg[STRERR_BUFSIZE];
 	int type, pfd, err;
 
-	err = add_kprobe_event_legacy(name, retprobe, offset);
+	err = add_kprobe_event_legacy(probe_name, retprobe, kfunc_name, offset);
 	if (err < 0) {
-		pr_warn("failed to add legacy kprobe event: %s\n",
+		pr_warn("failed to add legacy kprobe event for '%s+0x%zx': %s\n",
+			kfunc_name, offset,
 			libbpf_strerror_r(err, errmsg, sizeof(errmsg)));
 		return err;
 	}
-	type = determine_kprobe_perf_type_legacy(name, retprobe);
+	type = determine_kprobe_perf_type_legacy(probe_name, retprobe);
 	if (type < 0) {
-		pr_warn("failed to determine legacy kprobe event id: %s\n",
+		pr_warn("failed to determine legacy kprobe event id for '%s+0x%zx': %s\n",
+			kfunc_name, offset,
 			libbpf_strerror_r(type, errmsg, sizeof(errmsg)));
 		return type;
 	}
@@ -9340,7 +9347,7 @@ bpf_program__attach_kprobe_opts(const struct bpf_program *prog,
 	char errmsg[STRERR_BUFSIZE];
 	char *legacy_probe = NULL;
 	struct bpf_link *link;
-	unsigned long offset;
+	size_t offset;
 	bool retprobe, legacy;
 	int pfd, err;
 
@@ -9357,17 +9364,23 @@ bpf_program__attach_kprobe_opts(const struct bpf_program *prog,
 					    func_name, offset,
 					    -1 /* pid */, 0 /* ref_ctr_off */);
 	} else {
+		char probe_name[256];
+
+		gen_kprobe_legacy_event_name(probe_name, sizeof(probe_name),
+					     func_name, offset);
+
 		legacy_probe = strdup(func_name);
 		if (!legacy_probe)
 			return libbpf_err_ptr(-ENOMEM);
 
-		pfd = perf_event_kprobe_open_legacy(retprobe, func_name,
+		pfd = perf_event_kprobe_open_legacy(legacy_probe, retprobe, func_name,
 						    offset, -1 /* pid */);
 	}
 	if (pfd < 0) {
-		err = pfd;
-		pr_warn("prog '%s': failed to create %s '%s' perf event: %s\n",
-			prog->name, retprobe ? "kretprobe" : "kprobe", func_name,
+		err = -errno;
+		pr_warn("prog '%s': failed to create %s '%s+0x%zx' perf event: %s\n",
+			prog->name, retprobe ? "kretprobe" : "kprobe",
+			func_name, offset,
 			libbpf_strerror_r(err, errmsg, sizeof(errmsg)));
 		goto err_out;
 	}
@@ -9375,8 +9388,9 @@ bpf_program__attach_kprobe_opts(const struct bpf_program *prog,
 	err = libbpf_get_error(link);
 	if (err) {
 		close(pfd);
-		pr_warn("prog '%s': failed to attach to %s '%s': %s\n",
-			prog->name, retprobe ? "kretprobe" : "kprobe", func_name,
+		pr_warn("prog '%s': failed to attach to %s '%s+0x%zx': %s\n",
+			prog->name, retprobe ? "kretprobe" : "kprobe",
+			func_name, offset,
 			libbpf_strerror_r(err, errmsg, sizeof(errmsg)));
 		goto err_out;
 	}
@@ -9384,6 +9398,7 @@ bpf_program__attach_kprobe_opts(const struct bpf_program *prog,
 		struct bpf_link_perf *perf_link = container_of(link, struct bpf_link_perf, link);
 
 		perf_link->legacy_probe_name = legacy_probe;
+		perf_link->legacy_is_kprobe = true;
 		perf_link->legacy_is_retprobe = retprobe;
 	}
 
diff --git a/tools/lib/bpf/libbpf.h b/tools/lib/bpf/libbpf.h
index d0bedd673273..e35490c54eb3 100644
--- a/tools/lib/bpf/libbpf.h
+++ b/tools/lib/bpf/libbpf.h
@@ -269,7 +269,7 @@ struct bpf_kprobe_opts {
 	/* custom user-provided value fetchable through bpf_get_attach_cookie() */
 	__u64 bpf_cookie;
 	/* function's offset to install kprobe to */
-	unsigned long offset;
+	size_t offset;
 	/* kprobe is return probe */
 	bool retprobe;
 	size_t :0;
-- 
cgit v1.2.3


From cc10623c681019c608c0cb30e2b38994e2c90b2a Mon Sep 17 00:00:00 2001
From: Andrii Nakryiko <andrii@kernel.org>
Date: Tue, 21 Sep 2021 14:00:36 -0700
Subject: libbpf: Add legacy uprobe attaching support

Similarly to recently added legacy kprobe attach interface support
through tracefs, support attaching uprobes using the legacy interface if
host kernel doesn't support newer FD-based interface.

For uprobes event name consists of "libbpf_" prefix, PID, sanitized
binary path and offset within that binary. Structuraly the code is
aligned with kprobe logic refactoring in previous patch. struct
bpf_link_perf is re-used and all the same legacy_probe_name and
legacy_is_retprobe fields are used to ensure proper cleanup on
bpf_link__destroy().

Users should be aware, though, that on old kernels which don't support
FD-based interface for kprobe/uprobe attachment, if the application
crashes before bpf_link__destroy() is called, uprobe legacy
events will be left in tracefs. This is the same limitation as with
legacy kprobe interfaces.

Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20210921210036.1545557-5-andrii@kernel.org
---
 tools/lib/bpf/libbpf.c | 130 ++++++++++++++++++++++++++++++++++++++++++++++---
 1 file changed, 122 insertions(+), 8 deletions(-)

(limited to 'tools/lib/bpf')

diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index aa842f0721cb..ef5db34bf913 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -9021,6 +9021,7 @@ struct bpf_link_perf {
 };
 
 static int remove_kprobe_event_legacy(const char *probe_name, bool retprobe);
+static int remove_uprobe_event_legacy(const char *probe_name, bool retprobe);
 
 static int bpf_link_perf_detach(struct bpf_link *link)
 {
@@ -9034,11 +9035,14 @@ static int bpf_link_perf_detach(struct bpf_link *link)
 		close(perf_link->perf_event_fd);
 	close(link->fd);
 
-	/* legacy kprobe needs to be removed after perf event fd closure */
+	/* legacy uprobe/kprobe needs to be removed after perf event fd closure */
 	if (perf_link->legacy_probe_name) {
 		if (perf_link->legacy_is_kprobe) {
 			err = remove_kprobe_event_legacy(perf_link->legacy_probe_name,
 							 perf_link->legacy_is_retprobe);
+		} else {
+			err = remove_uprobe_event_legacy(perf_link->legacy_probe_name,
+							 perf_link->legacy_is_retprobe);
 		}
 	}
 
@@ -9450,17 +9454,96 @@ static struct bpf_link *attach_kprobe(const struct bpf_program *prog)
 	return link;
 }
 
+static void gen_uprobe_legacy_event_name(char *buf, size_t buf_sz,
+					 const char *binary_path, uint64_t offset)
+{
+	int i;
+
+	snprintf(buf, buf_sz, "libbpf_%u_%s_0x%zx", getpid(), binary_path, (size_t)offset);
+
+	/* sanitize binary_path in the probe name */
+	for (i = 0; buf[i]; i++) {
+		if (!isalnum(buf[i]))
+			buf[i] = '_';
+	}
+}
+
+static inline int add_uprobe_event_legacy(const char *probe_name, bool retprobe,
+					  const char *binary_path, size_t offset)
+{
+	const char *file = "/sys/kernel/debug/tracing/uprobe_events";
+
+	return append_to_file(file, "%c:%s/%s %s:0x%zx",
+			      retprobe ? 'r' : 'p',
+			      retprobe ? "uretprobes" : "uprobes",
+			      probe_name, binary_path, offset);
+}
+
+static inline int remove_uprobe_event_legacy(const char *probe_name, bool retprobe)
+{
+	const char *file = "/sys/kernel/debug/tracing/uprobe_events";
+
+	return append_to_file(file, "-:%s/%s", retprobe ? "uretprobes" : "uprobes", probe_name);
+}
+
+static int determine_uprobe_perf_type_legacy(const char *probe_name, bool retprobe)
+{
+	char file[512];
+
+	snprintf(file, sizeof(file),
+		 "/sys/kernel/debug/tracing/events/%s/%s/id",
+		 retprobe ? "uretprobes" : "uprobes", probe_name);
+
+	return parse_uint_from_file(file, "%d\n");
+}
+
+static int perf_event_uprobe_open_legacy(const char *probe_name, bool retprobe,
+					 const char *binary_path, size_t offset, int pid)
+{
+	struct perf_event_attr attr;
+	int type, pfd, err;
+
+	err = add_uprobe_event_legacy(probe_name, retprobe, binary_path, offset);
+	if (err < 0) {
+		pr_warn("failed to add legacy uprobe event for %s:0x%zx: %d\n",
+			binary_path, (size_t)offset, err);
+		return err;
+	}
+	type = determine_uprobe_perf_type_legacy(probe_name, retprobe);
+	if (type < 0) {
+		pr_warn("failed to determine legacy uprobe event id for %s:0x%zx: %d\n",
+			binary_path, offset, err);
+		return type;
+	}
+
+	memset(&attr, 0, sizeof(attr));
+	attr.size = sizeof(attr);
+	attr.config = type;
+	attr.type = PERF_TYPE_TRACEPOINT;
+
+	pfd = syscall(__NR_perf_event_open, &attr,
+		      pid < 0 ? -1 : pid, /* pid */
+		      pid == -1 ? 0 : -1, /* cpu */
+		      -1 /* group_fd */,  PERF_FLAG_FD_CLOEXEC);
+	if (pfd < 0) {
+		err = -errno;
+		pr_warn("legacy uprobe perf_event_open() failed: %d\n", err);
+		return err;
+	}
+	return pfd;
+}
+
 LIBBPF_API struct bpf_link *
 bpf_program__attach_uprobe_opts(const struct bpf_program *prog, pid_t pid,
 				const char *binary_path, size_t func_offset,
 				const struct bpf_uprobe_opts *opts)
 {
 	DECLARE_LIBBPF_OPTS(bpf_perf_event_opts, pe_opts);
-	char errmsg[STRERR_BUFSIZE];
+	char errmsg[STRERR_BUFSIZE], *legacy_probe = NULL;
 	struct bpf_link *link;
 	size_t ref_ctr_off;
 	int pfd, err;
-	bool retprobe;
+	bool retprobe, legacy;
 
 	if (!OPTS_VALID(opts, bpf_uprobe_opts))
 		return libbpf_err_ptr(-EINVAL);
@@ -9469,15 +9552,35 @@ bpf_program__attach_uprobe_opts(const struct bpf_program *prog, pid_t pid,
 	ref_ctr_off = OPTS_GET(opts, ref_ctr_offset, 0);
 	pe_opts.bpf_cookie = OPTS_GET(opts, bpf_cookie, 0);
 
-	pfd = perf_event_open_probe(true /* uprobe */, retprobe, binary_path,
-				    func_offset, pid, ref_ctr_off);
+	legacy = determine_uprobe_perf_type() < 0;
+	if (!legacy) {
+		pfd = perf_event_open_probe(true /* uprobe */, retprobe, binary_path,
+					    func_offset, pid, ref_ctr_off);
+	} else {
+		char probe_name[512];
+
+		if (ref_ctr_off)
+			return libbpf_err_ptr(-EINVAL);
+
+		gen_uprobe_legacy_event_name(probe_name, sizeof(probe_name),
+					     binary_path, func_offset);
+
+		legacy_probe = strdup(probe_name);
+		if (!legacy_probe)
+			return libbpf_err_ptr(-ENOMEM);
+
+		pfd = perf_event_uprobe_open_legacy(legacy_probe, retprobe,
+						    binary_path, func_offset, pid);
+	}
 	if (pfd < 0) {
+		err = -errno;
 		pr_warn("prog '%s': failed to create %s '%s:0x%zx' perf event: %s\n",
 			prog->name, retprobe ? "uretprobe" : "uprobe",
 			binary_path, func_offset,
-			libbpf_strerror_r(pfd, errmsg, sizeof(errmsg)));
-		return libbpf_err_ptr(pfd);
+			libbpf_strerror_r(err, errmsg, sizeof(errmsg)));
+		goto err_out;
 	}
+
 	link = bpf_program__attach_perf_event_opts(prog, pfd, &pe_opts);
 	err = libbpf_get_error(link);
 	if (err) {
@@ -9486,9 +9589,20 @@ bpf_program__attach_uprobe_opts(const struct bpf_program *prog, pid_t pid,
 			prog->name, retprobe ? "uretprobe" : "uprobe",
 			binary_path, func_offset,
 			libbpf_strerror_r(err, errmsg, sizeof(errmsg)));
-		return libbpf_err_ptr(err);
+		goto err_out;
+	}
+	if (legacy) {
+		struct bpf_link_perf *perf_link = container_of(link, struct bpf_link_perf, link);
+
+		perf_link->legacy_probe_name = legacy_probe;
+		perf_link->legacy_is_kprobe = false;
+		perf_link->legacy_is_retprobe = retprobe;
 	}
 	return link;
+err_out:
+	free(legacy_probe);
+	return libbpf_err_ptr(err);
+
 }
 
 struct bpf_link *bpf_program__attach_uprobe(const struct bpf_program *prog,
-- 
cgit v1.2.3


From c3e8c44a90631d2479fec6ecc6ba37e3188f487d Mon Sep 17 00:00:00 2001
From: Toke Høiland-Jørgensen <toke@redhat.com>
Date: Mon, 27 Sep 2021 22:58:10 +0200
Subject: libbpf: Ignore STT_SECTION symbols in 'maps' section
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

When parsing legacy map definitions, libbpf would error out when
encountering an STT_SECTION symbol. This becomes a problem because some
versions of binutils will produce SECTION symbols for every section when
processing an ELF file, so BPF files run through 'strip' will end up with
such symbols, making libbpf refuse to load them.

There's not really any reason why erroring out is strictly necessary, so
change libbpf to just ignore SECTION symbols when parsing the ELF.

Signed-off-by: Toke Høiland-Jørgensen <toke@redhat.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20210927205810.715656-1-toke@redhat.com
---
 tools/lib/bpf/libbpf.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

(limited to 'tools/lib/bpf')

diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index ef5db34bf913..453148fe8b4b 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -1869,6 +1869,8 @@ static int bpf_object__init_user_maps(struct bpf_object *obj, bool strict)
 			continue;
 		if (sym.st_shndx != obj->efile.maps_shndx)
 			continue;
+		if (GELF_ST_TYPE(sym.st_info) == STT_SECTION)
+			continue;
 
 		map = bpf_object__add_map(obj);
 		if (IS_ERR(map))
@@ -1881,8 +1883,7 @@ static int bpf_object__init_user_maps(struct bpf_object *obj, bool strict)
 			return -LIBBPF_ERRNO__FORMAT;
 		}
 
-		if (GELF_ST_TYPE(sym.st_info) == STT_SECTION
-		    || GELF_ST_BIND(sym.st_info) == STB_LOCAL) {
+		if (GELF_ST_BIND(sym.st_info) == STB_LOCAL) {
 			pr_warn("map '%s' (legacy): static maps are not supported\n", map_name);
 			return -ENOTSUP;
 		}
-- 
cgit v1.2.3


From 9673268f03ba72efcc00fa95f3fe3744fcae0dd0 Mon Sep 17 00:00:00 2001
From: Andrii Nakryiko <andrii@kernel.org>
Date: Tue, 28 Sep 2021 09:19:37 -0700
Subject: libbpf: Add "tc" SEC_DEF which is a better name for "classifier"

As argued in [0], add "tc" ELF section definition for SCHED_CLS BPF
program type. "classifier" is a misleading terminology and should be
migrated away from.

  [0] https://lore.kernel.org/bpf/270e27b1-e5be-5b1c-b343-51bd644d0747@iogearbox.net/

Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20210928161946.2512801-2-andrii@kernel.org
---
 tools/lib/bpf/libbpf.c | 1 +
 1 file changed, 1 insertion(+)

(limited to 'tools/lib/bpf')

diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index 453148fe8b4b..0bcd0a4c867a 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -7968,6 +7968,7 @@ static const struct bpf_sec_def section_defs[] = {
 		.attach_fn = attach_kprobe),
 	BPF_PROG_SEC("uretprobe/",		BPF_PROG_TYPE_KPROBE),
 	BPF_PROG_SEC("classifier",		BPF_PROG_TYPE_SCHED_CLS),
+	BPF_PROG_SEC("tc",			BPF_PROG_TYPE_SCHED_CLS),
 	BPF_PROG_SEC("action",			BPF_PROG_TYPE_SCHED_ACT),
 	SEC_DEF("tracepoint/", TRACEPOINT,
 		.attach_fn = attach_tp),
-- 
cgit v1.2.3


From 12d9466d8bf3d1d4b4fd0f5733b6fa0cc5ee1013 Mon Sep 17 00:00:00 2001
From: Andrii Nakryiko <andrii@kernel.org>
Date: Tue, 28 Sep 2021 09:19:41 -0700
Subject: libbpf: Refactor internal sec_def handling to enable pluggability

Refactor internals of libbpf to allow adding custom SEC() handling logic
easily from outside of libbpf. To that effect, each SEC()-handling
registration sets mandatory program type/expected attach type for
a given prefix and can provide three callbacks called at different
points of BPF program lifetime:

  - init callback for right after bpf_program is initialized and
  prog_type/expected_attach_type is set. This happens during
  bpf_object__open() step, close to the very end of constructing
  bpf_object, so all the libbpf APIs for querying and updating
  bpf_program properties should be available;

  - pre-load callback is called right before BPF_PROG_LOAD command is
  called in the kernel. This callbacks has ability to set both
  bpf_program properties, as well as program load attributes, overriding
  and augmenting the standard libbpf handling of them;

  - optional auto-attach callback, which makes a given SEC() handler
  support auto-attachment of a BPF program through bpf_program__attach()
  API and/or BPF skeletons <skel>__attach() method.

Each callbacks gets a `long cookie` parameter passed in, which is
specified during SEC() handling. This can be used by callbacks to lookup
whatever additional information is necessary.

This is not yet completely ready to be exposed to the outside world,
mainly due to non-public nature of struct bpf_prog_load_params. Instead
of making it part of public API, we'll wait until the planned low-level
libbpf API improvements for BPF_PROG_LOAD and other typical bpf()
syscall APIs, at which point we'll have a public, probably OPTS-based,
way to fully specify BPF program load parameters, which will be used as
an interface for custom pre-load callbacks.

But this change itself is already a good first step to unify the BPF
program hanling logic even within the libbpf itself. As one example, all
the extra per-program type handling (sleepable bit, attach_btf_id
resolution, unsetting optional expected attach type) is now more obvious
and is gathered in one place.

Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Dave Marchevsky <davemarchevsky@fb.com>
Link: https://lore.kernel.org/bpf/20210928161946.2512801-6-andrii@kernel.org
---
 tools/lib/bpf/libbpf.c | 129 +++++++++++++++++++++++++++++++++----------------
 1 file changed, 87 insertions(+), 42 deletions(-)

(limited to 'tools/lib/bpf')

diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index 0bcd0a4c867a..d4d56536dc4b 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -220,7 +220,9 @@ struct reloc_desc {
 
 struct bpf_sec_def;
 
-typedef struct bpf_link *(*attach_fn_t)(const struct bpf_program *prog);
+typedef int (*init_fn_t)(struct bpf_program *prog, long cookie);
+typedef int (*preload_fn_t)(struct bpf_program *prog, struct bpf_prog_load_params *attr, long cookie);
+typedef struct bpf_link *(*attach_fn_t)(const struct bpf_program *prog, long cookie);
 
 struct bpf_sec_def {
 	const char *sec;
@@ -231,7 +233,11 @@ struct bpf_sec_def {
 	bool is_attachable;
 	bool is_attach_btf;
 	bool is_sleepable;
+
+	init_fn_t init_fn;
+	preload_fn_t preload_fn;
 	attach_fn_t attach_fn;
+	long cookie;
 };
 
 /*
@@ -6095,6 +6101,44 @@ static int bpf_object__sanitize_prog(struct bpf_object *obj, struct bpf_program
 	return 0;
 }
 
+static int libbpf_find_attach_btf_id(struct bpf_program *prog, int *btf_obj_fd, int *btf_type_id);
+
+/* this is called as prog->sec_def->preload_fn for libbpf-supported sec_defs */
+static int libbpf_preload_prog(struct bpf_program *prog,
+			       struct bpf_prog_load_params *attr, long cookie)
+{
+	/* old kernels might not support specifying expected_attach_type */
+	if (prog->sec_def->is_exp_attach_type_optional &&
+	    !kernel_supports(prog->obj, FEAT_EXP_ATTACH_TYPE))
+		attr->expected_attach_type = 0;
+
+	if (prog->sec_def->is_sleepable)
+		attr->prog_flags |= BPF_F_SLEEPABLE;
+
+	if ((prog->type == BPF_PROG_TYPE_TRACING ||
+	     prog->type == BPF_PROG_TYPE_LSM ||
+	     prog->type == BPF_PROG_TYPE_EXT) && !prog->attach_btf_id) {
+		int btf_obj_fd = 0, btf_type_id = 0, err;
+
+		err = libbpf_find_attach_btf_id(prog, &btf_obj_fd, &btf_type_id);
+		if (err)
+			return err;
+
+		/* cache resolved BTF FD and BTF type ID in the prog */
+		prog->attach_btf_obj_fd = btf_obj_fd;
+		prog->attach_btf_id = btf_type_id;
+
+		/* but by now libbpf common logic is not utilizing
+		 * prog->atach_btf_obj_fd/prog->attach_btf_id anymore because
+		 * this callback is called after attrs were populated by
+		 * libbpf, so this callback has to update attr explicitly here
+		 */
+		attr->attach_btf_obj_fd = btf_obj_fd;
+		attr->attach_btf_id = btf_type_id;
+	}
+	return 0;
+}
+
 static int
 load_program(struct bpf_program *prog, struct bpf_insn *insns, int insns_cnt,
 	     char *license, __u32 kern_version, int *pfd)
@@ -6103,7 +6147,7 @@ load_program(struct bpf_program *prog, struct bpf_insn *insns, int insns_cnt,
 	char *cp, errmsg[STRERR_BUFSIZE];
 	size_t log_buf_size = 0;
 	char *log_buf = NULL;
-	int btf_fd, ret;
+	int btf_fd, ret, err;
 
 	if (prog->type == BPF_PROG_TYPE_UNSPEC) {
 		/*
@@ -6119,22 +6163,15 @@ load_program(struct bpf_program *prog, struct bpf_insn *insns, int insns_cnt,
 		return -EINVAL;
 
 	load_attr.prog_type = prog->type;
-	/* old kernels might not support specifying expected_attach_type */
-	if (!kernel_supports(prog->obj, FEAT_EXP_ATTACH_TYPE) && prog->sec_def &&
-	    prog->sec_def->is_exp_attach_type_optional)
-		load_attr.expected_attach_type = 0;
-	else
-		load_attr.expected_attach_type = prog->expected_attach_type;
+	load_attr.expected_attach_type = prog->expected_attach_type;
 	if (kernel_supports(prog->obj, FEAT_PROG_NAME))
 		load_attr.name = prog->name;
 	load_attr.insns = insns;
 	load_attr.insn_cnt = insns_cnt;
 	load_attr.license = license;
 	load_attr.attach_btf_id = prog->attach_btf_id;
-	if (prog->attach_prog_fd)
-		load_attr.attach_prog_fd = prog->attach_prog_fd;
-	else
-		load_attr.attach_btf_obj_fd = prog->attach_btf_obj_fd;
+	load_attr.attach_prog_fd = prog->attach_prog_fd;
+	load_attr.attach_btf_obj_fd = prog->attach_btf_obj_fd;
 	load_attr.attach_btf_id = prog->attach_btf_id;
 	load_attr.kern_version = kern_version;
 	load_attr.prog_ifindex = prog->prog_ifindex;
@@ -6153,6 +6190,16 @@ load_program(struct bpf_program *prog, struct bpf_insn *insns, int insns_cnt,
 	load_attr.log_level = prog->log_level;
 	load_attr.prog_flags = prog->prog_flags;
 
+	/* adjust load_attr if sec_def provides custom preload callback */
+	if (prog->sec_def && prog->sec_def->preload_fn) {
+		err = prog->sec_def->preload_fn(prog, &load_attr, prog->sec_def->cookie);
+		if (err < 0) {
+			pr_warn("prog '%s': failed to prepare load attributes: %d\n",
+				prog->name, err);
+			return err;
+		}
+	}
+
 	if (prog->obj->gen_loader) {
 		bpf_gen__prog_load(prog->obj->gen_loader, &load_attr,
 				   prog - prog->obj->programs);
@@ -6268,8 +6315,6 @@ static int bpf_program__record_externs(struct bpf_program *prog)
 	return 0;
 }
 
-static int libbpf_find_attach_btf_id(struct bpf_program *prog, int *btf_obj_fd, int *btf_type_id);
-
 int bpf_program__load(struct bpf_program *prog, char *license, __u32 kern_ver)
 {
 	int err = 0, fd, i;
@@ -6279,19 +6324,6 @@ int bpf_program__load(struct bpf_program *prog, char *license, __u32 kern_ver)
 		return libbpf_err(-EINVAL);
 	}
 
-	if ((prog->type == BPF_PROG_TYPE_TRACING ||
-	     prog->type == BPF_PROG_TYPE_LSM ||
-	     prog->type == BPF_PROG_TYPE_EXT) && !prog->attach_btf_id) {
-		int btf_obj_fd = 0, btf_type_id = 0;
-
-		err = libbpf_find_attach_btf_id(prog, &btf_obj_fd, &btf_type_id);
-		if (err)
-			return libbpf_err(err);
-
-		prog->attach_btf_obj_fd = btf_obj_fd;
-		prog->attach_btf_id = btf_type_id;
-	}
-
 	if (prog->instances.nr < 0 || !prog->instances.fds) {
 		if (prog->preprocessor) {
 			pr_warn("Internal error: can't load program '%s'\n",
@@ -6401,6 +6433,7 @@ static const struct bpf_sec_def *find_sec_def(const char *sec_name);
 static int bpf_object_init_progs(struct bpf_object *obj, const struct bpf_object_open_opts *opts)
 {
 	struct bpf_program *prog;
+	int err;
 
 	bpf_object__for_each_program(prog, obj) {
 		prog->sec_def = find_sec_def(prog->sec_name);
@@ -6411,8 +6444,6 @@ static int bpf_object_init_progs(struct bpf_object *obj, const struct bpf_object
 			continue;
 		}
 
-		if (prog->sec_def->is_sleepable)
-			prog->prog_flags |= BPF_F_SLEEPABLE;
 		bpf_program__set_type(prog, prog->sec_def->prog_type);
 		bpf_program__set_expected_attach_type(prog, prog->sec_def->expected_attach_type);
 
@@ -6422,6 +6453,18 @@ static int bpf_object_init_progs(struct bpf_object *obj, const struct bpf_object
 		    prog->sec_def->prog_type == BPF_PROG_TYPE_EXT)
 			prog->attach_prog_fd = OPTS_GET(opts, attach_prog_fd, 0);
 #pragma GCC diagnostic pop
+
+		/* sec_def can have custom callback which should be called
+		 * after bpf_program is initialized to adjust its properties
+		 */
+		if (prog->sec_def->init_fn) {
+			err = prog->sec_def->init_fn(prog, prog->sec_def->cookie);
+			if (err < 0) {
+				pr_warn("prog '%s': failed to initialize: %d\n",
+					prog->name, err);
+				return err;
+			}
+		}
 	}
 
 	return 0;
@@ -7919,6 +7962,7 @@ void bpf_program__set_expected_attach_type(struct bpf_program *prog,
 		.is_exp_attach_type_optional = eatype_optional,		    \
 		.is_attachable = attachable,				    \
 		.is_attach_btf = attach_btf,				    \
+		.preload_fn = libbpf_preload_prog,			    \
 	}
 
 /* Programs that can NOT be attached. */
@@ -7945,15 +7989,16 @@ void bpf_program__set_expected_attach_type(struct bpf_program *prog,
 	.sec = sec_pfx,							    \
 	.len = sizeof(sec_pfx) - 1,					    \
 	.prog_type = BPF_PROG_TYPE_##ptype,				    \
+	.preload_fn = libbpf_preload_prog,				    \
 	__VA_ARGS__							    \
 }
 
-static struct bpf_link *attach_kprobe(const struct bpf_program *prog);
-static struct bpf_link *attach_tp(const struct bpf_program *prog);
-static struct bpf_link *attach_raw_tp(const struct bpf_program *prog);
-static struct bpf_link *attach_trace(const struct bpf_program *prog);
-static struct bpf_link *attach_lsm(const struct bpf_program *prog);
-static struct bpf_link *attach_iter(const struct bpf_program *prog);
+static struct bpf_link *attach_kprobe(const struct bpf_program *prog, long cookie);
+static struct bpf_link *attach_tp(const struct bpf_program *prog, long cookie);
+static struct bpf_link *attach_raw_tp(const struct bpf_program *prog, long cookie);
+static struct bpf_link *attach_trace(const struct bpf_program *prog, long cookie);
+static struct bpf_link *attach_lsm(const struct bpf_program *prog, long cookie);
+static struct bpf_link *attach_iter(const struct bpf_program *prog, long cookie);
 
 static const struct bpf_sec_def section_defs[] = {
 	BPF_PROG_SEC("socket",			BPF_PROG_TYPE_SOCKET_FILTER),
@@ -9425,7 +9470,7 @@ struct bpf_link *bpf_program__attach_kprobe(const struct bpf_program *prog,
 	return bpf_program__attach_kprobe_opts(prog, func_name, &opts);
 }
 
-static struct bpf_link *attach_kprobe(const struct bpf_program *prog)
+static struct bpf_link *attach_kprobe(const struct bpf_program *prog, long cookie)
 {
 	DECLARE_LIBBPF_OPTS(bpf_kprobe_opts, opts);
 	unsigned long offset = 0;
@@ -9708,7 +9753,7 @@ struct bpf_link *bpf_program__attach_tracepoint(const struct bpf_program *prog,
 	return bpf_program__attach_tracepoint_opts(prog, tp_category, tp_name, NULL);
 }
 
-static struct bpf_link *attach_tp(const struct bpf_program *prog)
+static struct bpf_link *attach_tp(const struct bpf_program *prog, long cookie)
 {
 	char *sec_name, *tp_cat, *tp_name;
 	struct bpf_link *link;
@@ -9762,7 +9807,7 @@ struct bpf_link *bpf_program__attach_raw_tracepoint(const struct bpf_program *pr
 	return link;
 }
 
-static struct bpf_link *attach_raw_tp(const struct bpf_program *prog)
+static struct bpf_link *attach_raw_tp(const struct bpf_program *prog, long cookie)
 {
 	const char *tp_name = prog->sec_name + prog->sec_def->len;
 
@@ -9809,12 +9854,12 @@ struct bpf_link *bpf_program__attach_lsm(const struct bpf_program *prog)
 	return bpf_program__attach_btf_id(prog);
 }
 
-static struct bpf_link *attach_trace(const struct bpf_program *prog)
+static struct bpf_link *attach_trace(const struct bpf_program *prog, long cookie)
 {
 	return bpf_program__attach_trace(prog);
 }
 
-static struct bpf_link *attach_lsm(const struct bpf_program *prog)
+static struct bpf_link *attach_lsm(const struct bpf_program *prog, long cookie)
 {
 	return bpf_program__attach_lsm(prog);
 }
@@ -9945,7 +9990,7 @@ bpf_program__attach_iter(const struct bpf_program *prog,
 	return link;
 }
 
-static struct bpf_link *attach_iter(const struct bpf_program *prog)
+static struct bpf_link *attach_iter(const struct bpf_program *prog, long cookie)
 {
 	return bpf_program__attach_iter(prog, NULL);
 }
@@ -9955,7 +10000,7 @@ struct bpf_link *bpf_program__attach(const struct bpf_program *prog)
 	if (!prog->sec_def || !prog->sec_def->attach_fn)
 		return libbpf_err_ptr(-ESRCH);
 
-	return prog->sec_def->attach_fn(prog);
+	return prog->sec_def->attach_fn(prog, prog->sec_def->cookie);
 }
 
 static int bpf_link__detach_struct_ops(struct bpf_link *link)
-- 
cgit v1.2.3


From 13d35a0cf1741431333ba4aa9bce9c5bbc88f63b Mon Sep 17 00:00:00 2001
From: Andrii Nakryiko <andrii@kernel.org>
Date: Tue, 28 Sep 2021 09:19:42 -0700
Subject: libbpf: Reduce reliance of attach_fns on sec_def internals

Move closer to not relying on bpf_sec_def internals that won't be part
of public API, when pluggable SEC() handlers will be allowed. Drop
pre-calculated prefix length, and in various helpers don't rely on this
prefix length availability. Also minimize reliance on knowing
bpf_sec_def's prefix for few places where section prefix shortcuts are
supported (e.g., tp vs tracepoint, raw_tp vs raw_tracepoint).

Given checking some string for having a given string-constant prefix is
such a common operation and so annoying to be done with pure C code, add
a small macro helper, str_has_pfx(), and reuse it throughout libbpf.c
where prefix comparison is performed. With __builtin_constant_p() it's
possible to have a convenient helper that checks some string for having
a given prefix, where prefix is either string literal (or compile-time
known string due to compiler optimization) or just a runtime string
pointer, which is quite convenient and saves a lot of typing and string
literal duplication.

Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Dave Marchevsky <davemarchevsky@fb.com>
Link: https://lore.kernel.org/bpf/20210928161946.2512801-7-andrii@kernel.org
---
 tools/lib/bpf/libbpf.c          | 41 +++++++++++++++++++++++------------------
 tools/lib/bpf/libbpf_internal.h |  7 +++++++
 2 files changed, 30 insertions(+), 18 deletions(-)

(limited to 'tools/lib/bpf')

diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index d4d56536dc4b..f87ffd4d7eab 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -226,7 +226,6 @@ typedef struct bpf_link *(*attach_fn_t)(const struct bpf_program *prog, long coo
 
 struct bpf_sec_def {
 	const char *sec;
-	size_t len;
 	enum bpf_prog_type prog_type;
 	enum bpf_attach_type expected_attach_type;
 	bool is_exp_attach_type_optional;
@@ -1671,7 +1670,7 @@ static int bpf_object__process_kconfig_line(struct bpf_object *obj,
 	void *ext_val;
 	__u64 num;
 
-	if (strncmp(buf, "CONFIG_", 7))
+	if (!str_has_pfx(buf, "CONFIG_"))
 		return 0;
 
 	sep = strchr(buf, '=');
@@ -2920,7 +2919,7 @@ static Elf_Data *elf_sec_data(const struct bpf_object *obj, Elf_Scn *scn)
 static bool is_sec_name_dwarf(const char *name)
 {
 	/* approximation, but the actual list is too long */
-	return strncmp(name, ".debug_", sizeof(".debug_") - 1) == 0;
+	return str_has_pfx(name, ".debug_");
 }
 
 static bool ignore_elf_section(GElf_Shdr *hdr, const char *name)
@@ -2942,7 +2941,7 @@ static bool ignore_elf_section(GElf_Shdr *hdr, const char *name)
 	if (is_sec_name_dwarf(name))
 		return true;
 
-	if (strncmp(name, ".rel", sizeof(".rel") - 1) == 0) {
+	if (str_has_pfx(name, ".rel")) {
 		name += sizeof(".rel") - 1;
 		/* DWARF section relocations */
 		if (is_sec_name_dwarf(name))
@@ -6891,8 +6890,7 @@ static int bpf_object__resolve_externs(struct bpf_object *obj,
 			if (err)
 				return err;
 			pr_debug("extern (kcfg) %s=0x%x\n", ext->name, kver);
-		} else if (ext->type == EXT_KCFG &&
-			   strncmp(ext->name, "CONFIG_", 7) == 0) {
+		} else if (ext->type == EXT_KCFG && str_has_pfx(ext->name, "CONFIG_")) {
 			need_config = true;
 		} else if (ext->type == EXT_KSYM) {
 			if (ext->ksym.type_id)
@@ -7956,7 +7954,6 @@ void bpf_program__set_expected_attach_type(struct bpf_program *prog,
 			  attachable, attach_btf)			    \
 	{								    \
 		.sec = string,						    \
-		.len = sizeof(string) - 1,				    \
 		.prog_type = ptype,					    \
 		.expected_attach_type = eatype,				    \
 		.is_exp_attach_type_optional = eatype_optional,		    \
@@ -7987,7 +7984,6 @@ void bpf_program__set_expected_attach_type(struct bpf_program *prog,
 
 #define SEC_DEF(sec_pfx, ptype, ...) {					    \
 	.sec = sec_pfx,							    \
-	.len = sizeof(sec_pfx) - 1,					    \
 	.prog_type = BPF_PROG_TYPE_##ptype,				    \
 	.preload_fn = libbpf_preload_prog,				    \
 	__VA_ARGS__							    \
@@ -8162,10 +8158,8 @@ static const struct bpf_sec_def *find_sec_def(const char *sec_name)
 	int i, n = ARRAY_SIZE(section_defs);
 
 	for (i = 0; i < n; i++) {
-		if (strncmp(sec_name,
-			    section_defs[i].sec, section_defs[i].len))
-			continue;
-		return &section_defs[i];
+		if (str_has_pfx(sec_name, section_defs[i].sec))
+			return &section_defs[i];
 	}
 	return NULL;
 }
@@ -8519,7 +8513,7 @@ static int libbpf_find_attach_btf_id(struct bpf_program *prog, int *btf_obj_fd,
 			prog->sec_name);
 		return -ESRCH;
 	}
-	attach_name = prog->sec_name + prog->sec_def->len;
+	attach_name = prog->sec_name + strlen(prog->sec_def->sec);
 
 	/* BPF program's BTF ID */
 	if (attach_prog_fd) {
@@ -9479,8 +9473,11 @@ static struct bpf_link *attach_kprobe(const struct bpf_program *prog, long cooki
 	char *func;
 	int n, err;
 
-	func_name = prog->sec_name + prog->sec_def->len;
-	opts.retprobe = strcmp(prog->sec_def->sec, "kretprobe/") == 0;
+	opts.retprobe = str_has_pfx(prog->sec_name, "kretprobe/");
+	if (opts.retprobe)
+		func_name = prog->sec_name + sizeof("kretprobe/") - 1;
+	else
+		func_name = prog->sec_name + sizeof("kprobe/") - 1;
 
 	n = sscanf(func_name, "%m[a-zA-Z0-9_.]+%li", &func, &offset);
 	if (n < 1) {
@@ -9762,8 +9759,11 @@ static struct bpf_link *attach_tp(const struct bpf_program *prog, long cookie)
 	if (!sec_name)
 		return libbpf_err_ptr(-ENOMEM);
 
-	/* extract "tp/<category>/<name>" */
-	tp_cat = sec_name + prog->sec_def->len;
+	/* extract "tp/<category>/<name>" or "tracepoint/<category>/<name>" */
+	if (str_has_pfx(prog->sec_name, "tp/"))
+		tp_cat = sec_name + sizeof("tp/") - 1;
+	else
+		tp_cat = sec_name + sizeof("tracepoint/") - 1;
 	tp_name = strchr(tp_cat, '/');
 	if (!tp_name) {
 		free(sec_name);
@@ -9809,7 +9809,12 @@ struct bpf_link *bpf_program__attach_raw_tracepoint(const struct bpf_program *pr
 
 static struct bpf_link *attach_raw_tp(const struct bpf_program *prog, long cookie)
 {
-	const char *tp_name = prog->sec_name + prog->sec_def->len;
+	const char *tp_name;
+
+	if (str_has_pfx(prog->sec_name, "raw_tp/"))
+		tp_name = prog->sec_name + sizeof("raw_tp/") - 1;
+	else
+		tp_name = prog->sec_name + sizeof("raw_tracepoint/") - 1;
 
 	return bpf_program__attach_raw_tracepoint(prog, tp_name);
 }
diff --git a/tools/lib/bpf/libbpf_internal.h b/tools/lib/bpf/libbpf_internal.h
index ceb0c98979bc..ec79400517d4 100644
--- a/tools/lib/bpf/libbpf_internal.h
+++ b/tools/lib/bpf/libbpf_internal.h
@@ -89,6 +89,13 @@
 	(offsetof(TYPE, FIELD) + sizeof(((TYPE *)0)->FIELD))
 #endif
 
+/* Check whether a string `str` has prefix `pfx`, regardless if `pfx` is
+ * a string literal known at compilation time or char * pointer known only at
+ * runtime.
+ */
+#define str_has_pfx(str, pfx) \
+	(strncmp(str, pfx, __builtin_constant_p(pfx) ? sizeof(pfx) - 1 : strlen(pfx)) == 0)
+
 /* Symbol versioning is different between static and shared library.
  * Properly versioned symbols are needed for shared library, but
  * only the symbol of the new version is needed for static library.
-- 
cgit v1.2.3


From 15ea31fadd7f5b1076b4f91f75562bc319799c24 Mon Sep 17 00:00:00 2001
From: Andrii Nakryiko <andrii@kernel.org>
Date: Tue, 28 Sep 2021 09:19:43 -0700
Subject: libbpf: Refactor ELF section handler definitions

Refactor ELF section handler definitions table to use a set of flags and
unified SEC_DEF() macro. This allows for more succinct and table-like
set of definitions, and allows to more easily extend the logic without
adding more verbosity (this is utilized in later patches in the series).

This approach is also making libbpf-internal program pre-load callback
not rely on bpf_sec_def definition, which demonstrates that future
pluggable ELF section handlers will be able to achieve similar level of
integration without libbpf having to expose extra types and APIs.

For starters, update SEC_DEF() definitions and make them more succinct.
Also convert BPF_PROG_SEC() and BPF_APROG_COMPAT() definitions to
a common SEC_DEF() use.

Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Dave Marchevsky <davemarchevsky@fb.com>
Link: https://lore.kernel.org/bpf/20210928161946.2512801-8-andrii@kernel.org
---
 tools/lib/bpf/libbpf.c | 195 +++++++++++++++++++++----------------------------
 1 file changed, 84 insertions(+), 111 deletions(-)

(limited to 'tools/lib/bpf')

diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index f87ffd4d7eab..954c135a8adf 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -224,19 +224,35 @@ typedef int (*init_fn_t)(struct bpf_program *prog, long cookie);
 typedef int (*preload_fn_t)(struct bpf_program *prog, struct bpf_prog_load_params *attr, long cookie);
 typedef struct bpf_link *(*attach_fn_t)(const struct bpf_program *prog, long cookie);
 
+/* stored as sec_def->cookie for all libbpf-supported SEC()s */
+enum sec_def_flags {
+	SEC_NONE = 0,
+	/* expected_attach_type is optional, if kernel doesn't support that */
+	SEC_EXP_ATTACH_OPT = 1,
+	/* legacy, only used by libbpf_get_type_names() and
+	 * libbpf_attach_type_by_name(), not used by libbpf itself at all.
+	 * This used to be associated with cgroup (and few other) BPF programs
+	 * that were attachable through BPF_PROG_ATTACH command. Pretty
+	 * meaningless nowadays, though.
+	 */
+	SEC_ATTACHABLE = 2,
+	SEC_ATTACHABLE_OPT = SEC_ATTACHABLE | SEC_EXP_ATTACH_OPT,
+	/* attachment target is specified through BTF ID in either kernel or
+	 * other BPF program's BTF object */
+	SEC_ATTACH_BTF = 4,
+	/* BPF program type allows sleeping/blocking in kernel */
+	SEC_SLEEPABLE = 8,
+};
+
 struct bpf_sec_def {
 	const char *sec;
 	enum bpf_prog_type prog_type;
 	enum bpf_attach_type expected_attach_type;
-	bool is_exp_attach_type_optional;
-	bool is_attachable;
-	bool is_attach_btf;
-	bool is_sleepable;
+	long cookie;
 
 	init_fn_t init_fn;
 	preload_fn_t preload_fn;
 	attach_fn_t attach_fn;
-	long cookie;
 };
 
 /*
@@ -6100,26 +6116,30 @@ static int bpf_object__sanitize_prog(struct bpf_object *obj, struct bpf_program
 	return 0;
 }
 
-static int libbpf_find_attach_btf_id(struct bpf_program *prog, int *btf_obj_fd, int *btf_type_id);
+static int libbpf_find_attach_btf_id(struct bpf_program *prog, const char *attach_name,
+				     int *btf_obj_fd, int *btf_type_id);
 
 /* this is called as prog->sec_def->preload_fn for libbpf-supported sec_defs */
 static int libbpf_preload_prog(struct bpf_program *prog,
 			       struct bpf_prog_load_params *attr, long cookie)
 {
+	enum sec_def_flags def = cookie;
+
 	/* old kernels might not support specifying expected_attach_type */
-	if (prog->sec_def->is_exp_attach_type_optional &&
-	    !kernel_supports(prog->obj, FEAT_EXP_ATTACH_TYPE))
+	if ((def & SEC_EXP_ATTACH_OPT) && !kernel_supports(prog->obj, FEAT_EXP_ATTACH_TYPE))
 		attr->expected_attach_type = 0;
 
-	if (prog->sec_def->is_sleepable)
+	if (def & SEC_SLEEPABLE)
 		attr->prog_flags |= BPF_F_SLEEPABLE;
 
 	if ((prog->type == BPF_PROG_TYPE_TRACING ||
 	     prog->type == BPF_PROG_TYPE_LSM ||
 	     prog->type == BPF_PROG_TYPE_EXT) && !prog->attach_btf_id) {
 		int btf_obj_fd = 0, btf_type_id = 0, err;
+		const char *attach_name;
 
-		err = libbpf_find_attach_btf_id(prog, &btf_obj_fd, &btf_type_id);
+		attach_name = strchr(prog->sec_name, '/') + 1;
+		err = libbpf_find_attach_btf_id(prog, attach_name, &btf_obj_fd, &btf_type_id);
 		if (err)
 			return err;
 
@@ -7956,15 +7976,14 @@ void bpf_program__set_expected_attach_type(struct bpf_program *prog,
 		.sec = string,						    \
 		.prog_type = ptype,					    \
 		.expected_attach_type = eatype,				    \
-		.is_exp_attach_type_optional = eatype_optional,		    \
-		.is_attachable = attachable,				    \
-		.is_attach_btf = attach_btf,				    \
+		.cookie = (long) (					    \
+			(eatype_optional ? SEC_EXP_ATTACH_OPT : 0) |   \
+			(attachable ? SEC_ATTACHABLE : 0) |		    \
+			(attach_btf ? SEC_ATTACH_BTF : 0)		    \
+		),							    \
 		.preload_fn = libbpf_preload_prog,			    \
 	}
 
-/* Programs that can NOT be attached. */
-#define BPF_PROG_SEC(string, ptype) BPF_PROG_SEC_IMPL(string, ptype, 0, 0, 0, 0)
-
 /* Programs that can be attached. */
 #define BPF_APROG_SEC(string, ptype, atype) \
 	BPF_PROG_SEC_IMPL(string, ptype, atype, true, 1, 0)
@@ -7977,14 +7996,11 @@ void bpf_program__set_expected_attach_type(struct bpf_program *prog,
 #define BPF_PROG_BTF(string, ptype, eatype) \
 	BPF_PROG_SEC_IMPL(string, ptype, eatype, false, 0, 1)
 
-/* Programs that can be attached but attach type can't be identified by section
- * name. Kept for backward compatibility.
- */
-#define BPF_APROG_COMPAT(string, ptype) BPF_PROG_SEC(string, ptype)
-
-#define SEC_DEF(sec_pfx, ptype, ...) {					    \
+#define SEC_DEF(sec_pfx, ptype, atype, flags, ...) {			    \
 	.sec = sec_pfx,							    \
 	.prog_type = BPF_PROG_TYPE_##ptype,				    \
+	.expected_attach_type = atype,					    \
+	.cookie = (long)(flags),					    \
 	.preload_fn = libbpf_preload_prog,				    \
 	__VA_ARGS__							    \
 }
@@ -7997,93 +8013,50 @@ static struct bpf_link *attach_lsm(const struct bpf_program *prog, long cookie);
 static struct bpf_link *attach_iter(const struct bpf_program *prog, long cookie);
 
 static const struct bpf_sec_def section_defs[] = {
-	BPF_PROG_SEC("socket",			BPF_PROG_TYPE_SOCKET_FILTER),
+	SEC_DEF("socket",		SOCKET_FILTER, 0, SEC_NONE),
 	BPF_EAPROG_SEC("sk_reuseport/migrate",	BPF_PROG_TYPE_SK_REUSEPORT,
 						BPF_SK_REUSEPORT_SELECT_OR_MIGRATE),
 	BPF_EAPROG_SEC("sk_reuseport",		BPF_PROG_TYPE_SK_REUSEPORT,
 						BPF_SK_REUSEPORT_SELECT),
-	SEC_DEF("kprobe/", KPROBE,
-		.attach_fn = attach_kprobe),
-	BPF_PROG_SEC("uprobe/",			BPF_PROG_TYPE_KPROBE),
-	SEC_DEF("kretprobe/", KPROBE,
-		.attach_fn = attach_kprobe),
-	BPF_PROG_SEC("uretprobe/",		BPF_PROG_TYPE_KPROBE),
-	BPF_PROG_SEC("classifier",		BPF_PROG_TYPE_SCHED_CLS),
-	BPF_PROG_SEC("tc",			BPF_PROG_TYPE_SCHED_CLS),
-	BPF_PROG_SEC("action",			BPF_PROG_TYPE_SCHED_ACT),
-	SEC_DEF("tracepoint/", TRACEPOINT,
-		.attach_fn = attach_tp),
-	SEC_DEF("tp/", TRACEPOINT,
-		.attach_fn = attach_tp),
-	SEC_DEF("raw_tracepoint/", RAW_TRACEPOINT,
-		.attach_fn = attach_raw_tp),
-	SEC_DEF("raw_tp/", RAW_TRACEPOINT,
-		.attach_fn = attach_raw_tp),
-	SEC_DEF("tp_btf/", TRACING,
-		.expected_attach_type = BPF_TRACE_RAW_TP,
-		.is_attach_btf = true,
-		.attach_fn = attach_trace),
-	SEC_DEF("fentry/", TRACING,
-		.expected_attach_type = BPF_TRACE_FENTRY,
-		.is_attach_btf = true,
-		.attach_fn = attach_trace),
-	SEC_DEF("fmod_ret/", TRACING,
-		.expected_attach_type = BPF_MODIFY_RETURN,
-		.is_attach_btf = true,
-		.attach_fn = attach_trace),
-	SEC_DEF("fexit/", TRACING,
-		.expected_attach_type = BPF_TRACE_FEXIT,
-		.is_attach_btf = true,
-		.attach_fn = attach_trace),
-	SEC_DEF("fentry.s/", TRACING,
-		.expected_attach_type = BPF_TRACE_FENTRY,
-		.is_attach_btf = true,
-		.is_sleepable = true,
-		.attach_fn = attach_trace),
-	SEC_DEF("fmod_ret.s/", TRACING,
-		.expected_attach_type = BPF_MODIFY_RETURN,
-		.is_attach_btf = true,
-		.is_sleepable = true,
-		.attach_fn = attach_trace),
-	SEC_DEF("fexit.s/", TRACING,
-		.expected_attach_type = BPF_TRACE_FEXIT,
-		.is_attach_btf = true,
-		.is_sleepable = true,
-		.attach_fn = attach_trace),
-	SEC_DEF("freplace/", EXT,
-		.is_attach_btf = true,
-		.attach_fn = attach_trace),
-	SEC_DEF("lsm/", LSM,
-		.is_attach_btf = true,
-		.expected_attach_type = BPF_LSM_MAC,
-		.attach_fn = attach_lsm),
-	SEC_DEF("lsm.s/", LSM,
-		.is_attach_btf = true,
-		.is_sleepable = true,
-		.expected_attach_type = BPF_LSM_MAC,
-		.attach_fn = attach_lsm),
-	SEC_DEF("iter/", TRACING,
-		.expected_attach_type = BPF_TRACE_ITER,
-		.is_attach_btf = true,
-		.attach_fn = attach_iter),
-	SEC_DEF("syscall", SYSCALL,
-		.is_sleepable = true),
+	SEC_DEF("kprobe/",		KPROBE,	0, SEC_NONE, attach_kprobe),
+	SEC_DEF("uprobe/",		KPROBE,	0, SEC_NONE),
+	SEC_DEF("kretprobe/",		KPROBE, 0, SEC_NONE, attach_kprobe),
+	SEC_DEF("uretprobe/",		KPROBE, 0, SEC_NONE),
+	SEC_DEF("classifier",		SCHED_CLS, 0, SEC_NONE),
+	SEC_DEF("tc",			SCHED_CLS, 0, SEC_NONE),
+	SEC_DEF("action",		SCHED_ACT, 0, SEC_NONE),
+	SEC_DEF("tracepoint/",		TRACEPOINT, 0, SEC_NONE, attach_tp),
+	SEC_DEF("tp/",			TRACEPOINT, 0, SEC_NONE, attach_tp),
+	SEC_DEF("raw_tracepoint/",	RAW_TRACEPOINT, 0, SEC_NONE, attach_raw_tp),
+	SEC_DEF("raw_tp/",		RAW_TRACEPOINT, 0, SEC_NONE, attach_raw_tp),
+	SEC_DEF("tp_btf/",		TRACING, BPF_TRACE_RAW_TP, SEC_ATTACH_BTF, attach_trace),
+	SEC_DEF("fentry/",		TRACING, BPF_TRACE_FENTRY, SEC_ATTACH_BTF, attach_trace),
+	SEC_DEF("fmod_ret/",		TRACING, BPF_MODIFY_RETURN, SEC_ATTACH_BTF, attach_trace),
+	SEC_DEF("fexit/",		TRACING, BPF_TRACE_FEXIT, SEC_ATTACH_BTF, attach_trace),
+	SEC_DEF("fentry.s/",		TRACING, BPF_TRACE_FENTRY, SEC_ATTACH_BTF | SEC_SLEEPABLE, attach_trace),
+	SEC_DEF("fmod_ret.s/",		TRACING, BPF_MODIFY_RETURN, SEC_ATTACH_BTF | SEC_SLEEPABLE, attach_trace),
+	SEC_DEF("fexit.s/",		TRACING, BPF_TRACE_FEXIT, SEC_ATTACH_BTF | SEC_SLEEPABLE, attach_trace),
+	SEC_DEF("freplace/",		EXT, 0, SEC_ATTACH_BTF, attach_trace),
+	SEC_DEF("lsm/",			LSM, BPF_LSM_MAC, SEC_ATTACH_BTF, attach_lsm),
+	SEC_DEF("lsm.s/",		LSM, BPF_LSM_MAC, SEC_ATTACH_BTF | SEC_SLEEPABLE, attach_lsm),
+	SEC_DEF("iter/",		TRACING, BPF_TRACE_ITER, SEC_ATTACH_BTF, attach_iter),
+	SEC_DEF("syscall",		SYSCALL, 0, SEC_SLEEPABLE),
 	BPF_EAPROG_SEC("xdp_devmap/",		BPF_PROG_TYPE_XDP,
 						BPF_XDP_DEVMAP),
 	BPF_EAPROG_SEC("xdp_cpumap/",		BPF_PROG_TYPE_XDP,
 						BPF_XDP_CPUMAP),
 	BPF_APROG_SEC("xdp",			BPF_PROG_TYPE_XDP,
 						BPF_XDP),
-	BPF_PROG_SEC("perf_event",		BPF_PROG_TYPE_PERF_EVENT),
-	BPF_PROG_SEC("lwt_in",			BPF_PROG_TYPE_LWT_IN),
-	BPF_PROG_SEC("lwt_out",			BPF_PROG_TYPE_LWT_OUT),
-	BPF_PROG_SEC("lwt_xmit",		BPF_PROG_TYPE_LWT_XMIT),
-	BPF_PROG_SEC("lwt_seg6local",		BPF_PROG_TYPE_LWT_SEG6LOCAL),
+	SEC_DEF("perf_event",		PERF_EVENT, 0, SEC_NONE),
+	SEC_DEF("lwt_in",		LWT_IN, 0, SEC_NONE),
+	SEC_DEF("lwt_out",		LWT_OUT, 0, SEC_NONE),
+	SEC_DEF("lwt_xmit",		LWT_XMIT, 0, SEC_NONE),
+	SEC_DEF("lwt_seg6local",	LWT_SEG6LOCAL, 0, SEC_NONE),
 	BPF_APROG_SEC("cgroup_skb/ingress",	BPF_PROG_TYPE_CGROUP_SKB,
 						BPF_CGROUP_INET_INGRESS),
 	BPF_APROG_SEC("cgroup_skb/egress",	BPF_PROG_TYPE_CGROUP_SKB,
 						BPF_CGROUP_INET_EGRESS),
-	BPF_APROG_COMPAT("cgroup/skb",		BPF_PROG_TYPE_CGROUP_SKB),
+	SEC_DEF("cgroup/skb",		CGROUP_SKB, 0, SEC_NONE),
 	BPF_EAPROG_SEC("cgroup/sock_create",	BPF_PROG_TYPE_CGROUP_SOCK,
 						BPF_CGROUP_INET_SOCK_CREATE),
 	BPF_EAPROG_SEC("cgroup/sock_release",	BPF_PROG_TYPE_CGROUP_SOCK,
@@ -8102,7 +8075,7 @@ static const struct bpf_sec_def section_defs[] = {
 						BPF_SK_SKB_STREAM_PARSER),
 	BPF_APROG_SEC("sk_skb/stream_verdict",	BPF_PROG_TYPE_SK_SKB,
 						BPF_SK_SKB_STREAM_VERDICT),
-	BPF_APROG_COMPAT("sk_skb",		BPF_PROG_TYPE_SK_SKB),
+	SEC_DEF("sk_skb",		SK_SKB, 0, SEC_NONE),
 	BPF_APROG_SEC("sk_msg",			BPF_PROG_TYPE_SK_MSG,
 						BPF_SK_MSG_VERDICT),
 	BPF_APROG_SEC("lirc_mode2",		BPF_PROG_TYPE_LIRC_MODE2,
@@ -8139,16 +8112,14 @@ static const struct bpf_sec_def section_defs[] = {
 						BPF_CGROUP_GETSOCKOPT),
 	BPF_EAPROG_SEC("cgroup/setsockopt",	BPF_PROG_TYPE_CGROUP_SOCKOPT,
 						BPF_CGROUP_SETSOCKOPT),
-	BPF_PROG_SEC("struct_ops",		BPF_PROG_TYPE_STRUCT_OPS),
+	SEC_DEF("struct_ops",		STRUCT_OPS, 0, SEC_NONE),
 	BPF_EAPROG_SEC("sk_lookup/",		BPF_PROG_TYPE_SK_LOOKUP,
 						BPF_SK_LOOKUP),
 };
 
 #undef BPF_PROG_SEC_IMPL
-#undef BPF_PROG_SEC
 #undef BPF_APROG_SEC
 #undef BPF_EAPROG_SEC
-#undef BPF_APROG_COMPAT
 #undef SEC_DEF
 
 #define MAX_TYPE_NAME_SIZE 32
@@ -8176,8 +8147,15 @@ static char *libbpf_get_type_names(bool attach_type)
 	buf[0] = '\0';
 	/* Forge string buf with all available names */
 	for (i = 0; i < ARRAY_SIZE(section_defs); i++) {
-		if (attach_type && !section_defs[i].is_attachable)
-			continue;
+		const struct bpf_sec_def *sec_def = &section_defs[i];
+
+		if (attach_type) {
+			if (sec_def->preload_fn != libbpf_preload_prog)
+				continue;
+
+			if (!(sec_def->cookie & SEC_ATTACHABLE))
+				continue;
+		}
 
 		if (strlen(buf) + strlen(section_defs[i].sec) + 2 > len) {
 			free(buf);
@@ -8501,20 +8479,13 @@ static int find_kernel_btf_id(struct bpf_object *obj, const char *attach_name,
 	return -ESRCH;
 }
 
-static int libbpf_find_attach_btf_id(struct bpf_program *prog, int *btf_obj_fd, int *btf_type_id)
+static int libbpf_find_attach_btf_id(struct bpf_program *prog, const char *attach_name,
+				     int *btf_obj_fd, int *btf_type_id)
 {
 	enum bpf_attach_type attach_type = prog->expected_attach_type;
 	__u32 attach_prog_fd = prog->attach_prog_fd;
-	const char *attach_name;
 	int err = 0;
 
-	if (!prog->sec_def || !prog->sec_def->is_attach_btf) {
-		pr_warn("failed to identify BTF ID based on ELF section name '%s'\n",
-			prog->sec_name);
-		return -ESRCH;
-	}
-	attach_name = prog->sec_name + strlen(prog->sec_def->sec);
-
 	/* BPF program's BTF ID */
 	if (attach_prog_fd) {
 		err = libbpf_find_prog_btf_id(attach_name, attach_prog_fd);
@@ -8564,7 +8535,9 @@ int libbpf_attach_type_by_name(const char *name,
 		return libbpf_err(-EINVAL);
 	}
 
-	if (!sec_def->is_attachable)
+	if (sec_def->preload_fn != libbpf_preload_prog)
+		return libbpf_err(-EINVAL);
+	if (!(sec_def->cookie & SEC_ATTACHABLE))
 		return libbpf_err(-EINVAL);
 
 	*attach_type = sec_def->expected_attach_type;
-- 
cgit v1.2.3


From d41ea045a6e461673d1b2fad106b8cd04c3ba863 Mon Sep 17 00:00:00 2001
From: Andrii Nakryiko <andrii@kernel.org>
Date: Tue, 28 Sep 2021 09:19:44 -0700
Subject: libbpf: Complete SEC() table unification for
 BPF_APROG_SEC/BPF_EAPROG_SEC

Complete SEC() table refactoring towards unified form by rewriting
BPF_APROG_SEC and BPF_EAPROG_SEC definitions with
SEC_DEF(SEC_ATTACHABLE_OPT) (for optional expected_attach_type) and
SEC_DEF(SEC_ATTACHABLE) (mandatory expected_attach_type), respectively.
Drop BPF_APROG_SEC, BPF_EAPROG_SEC, and BPF_PROG_SEC_IMPL macros after
that, leaving SEC_DEF() macro as the only one used.

Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Dave Marchevsky <davemarchevsky@fb.com>
Link: https://lore.kernel.org/bpf/20210928161946.2512801-9-andrii@kernel.org
---
 tools/lib/bpf/libbpf.c | 136 +++++++++++++------------------------------------
 1 file changed, 35 insertions(+), 101 deletions(-)

(limited to 'tools/lib/bpf')

diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index 954c135a8adf..4ba67dff6b0d 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -7970,32 +7970,6 @@ void bpf_program__set_expected_attach_type(struct bpf_program *prog,
 	prog->expected_attach_type = type;
 }
 
-#define BPF_PROG_SEC_IMPL(string, ptype, eatype, eatype_optional,	    \
-			  attachable, attach_btf)			    \
-	{								    \
-		.sec = string,						    \
-		.prog_type = ptype,					    \
-		.expected_attach_type = eatype,				    \
-		.cookie = (long) (					    \
-			(eatype_optional ? SEC_EXP_ATTACH_OPT : 0) |   \
-			(attachable ? SEC_ATTACHABLE : 0) |		    \
-			(attach_btf ? SEC_ATTACH_BTF : 0)		    \
-		),							    \
-		.preload_fn = libbpf_preload_prog,			    \
-	}
-
-/* Programs that can be attached. */
-#define BPF_APROG_SEC(string, ptype, atype) \
-	BPF_PROG_SEC_IMPL(string, ptype, atype, true, 1, 0)
-
-/* Programs that must specify expected attach type at load time. */
-#define BPF_EAPROG_SEC(string, ptype, eatype) \
-	BPF_PROG_SEC_IMPL(string, ptype, eatype, false, 1, 0)
-
-/* Programs that use BTF to identify attach point */
-#define BPF_PROG_BTF(string, ptype, eatype) \
-	BPF_PROG_SEC_IMPL(string, ptype, eatype, false, 0, 1)
-
 #define SEC_DEF(sec_pfx, ptype, atype, flags, ...) {			    \
 	.sec = sec_pfx,							    \
 	.prog_type = BPF_PROG_TYPE_##ptype,				    \
@@ -8014,10 +7988,8 @@ static struct bpf_link *attach_iter(const struct bpf_program *prog, long cookie)
 
 static const struct bpf_sec_def section_defs[] = {
 	SEC_DEF("socket",		SOCKET_FILTER, 0, SEC_NONE),
-	BPF_EAPROG_SEC("sk_reuseport/migrate",	BPF_PROG_TYPE_SK_REUSEPORT,
-						BPF_SK_REUSEPORT_SELECT_OR_MIGRATE),
-	BPF_EAPROG_SEC("sk_reuseport",		BPF_PROG_TYPE_SK_REUSEPORT,
-						BPF_SK_REUSEPORT_SELECT),
+	SEC_DEF("sk_reuseport/migrate",	SK_REUSEPORT, BPF_SK_REUSEPORT_SELECT_OR_MIGRATE, SEC_ATTACHABLE),
+	SEC_DEF("sk_reuseport",		SK_REUSEPORT, BPF_SK_REUSEPORT_SELECT, SEC_ATTACHABLE),
 	SEC_DEF("kprobe/",		KPROBE,	0, SEC_NONE, attach_kprobe),
 	SEC_DEF("uprobe/",		KPROBE,	0, SEC_NONE),
 	SEC_DEF("kretprobe/",		KPROBE, 0, SEC_NONE, attach_kprobe),
@@ -8041,87 +8013,49 @@ static const struct bpf_sec_def section_defs[] = {
 	SEC_DEF("lsm.s/",		LSM, BPF_LSM_MAC, SEC_ATTACH_BTF | SEC_SLEEPABLE, attach_lsm),
 	SEC_DEF("iter/",		TRACING, BPF_TRACE_ITER, SEC_ATTACH_BTF, attach_iter),
 	SEC_DEF("syscall",		SYSCALL, 0, SEC_SLEEPABLE),
-	BPF_EAPROG_SEC("xdp_devmap/",		BPF_PROG_TYPE_XDP,
-						BPF_XDP_DEVMAP),
-	BPF_EAPROG_SEC("xdp_cpumap/",		BPF_PROG_TYPE_XDP,
-						BPF_XDP_CPUMAP),
-	BPF_APROG_SEC("xdp",			BPF_PROG_TYPE_XDP,
-						BPF_XDP),
+	SEC_DEF("xdp_devmap/",		XDP, BPF_XDP_DEVMAP, SEC_ATTACHABLE),
+	SEC_DEF("xdp_cpumap/",		XDP, BPF_XDP_CPUMAP, SEC_ATTACHABLE),
+	SEC_DEF("xdp",			XDP, BPF_XDP, SEC_ATTACHABLE_OPT),
 	SEC_DEF("perf_event",		PERF_EVENT, 0, SEC_NONE),
 	SEC_DEF("lwt_in",		LWT_IN, 0, SEC_NONE),
 	SEC_DEF("lwt_out",		LWT_OUT, 0, SEC_NONE),
 	SEC_DEF("lwt_xmit",		LWT_XMIT, 0, SEC_NONE),
 	SEC_DEF("lwt_seg6local",	LWT_SEG6LOCAL, 0, SEC_NONE),
-	BPF_APROG_SEC("cgroup_skb/ingress",	BPF_PROG_TYPE_CGROUP_SKB,
-						BPF_CGROUP_INET_INGRESS),
-	BPF_APROG_SEC("cgroup_skb/egress",	BPF_PROG_TYPE_CGROUP_SKB,
-						BPF_CGROUP_INET_EGRESS),
+	SEC_DEF("cgroup_skb/ingress",	CGROUP_SKB, BPF_CGROUP_INET_INGRESS, SEC_ATTACHABLE_OPT),
+	SEC_DEF("cgroup_skb/egress",	CGROUP_SKB, BPF_CGROUP_INET_EGRESS, SEC_ATTACHABLE_OPT),
 	SEC_DEF("cgroup/skb",		CGROUP_SKB, 0, SEC_NONE),
-	BPF_EAPROG_SEC("cgroup/sock_create",	BPF_PROG_TYPE_CGROUP_SOCK,
-						BPF_CGROUP_INET_SOCK_CREATE),
-	BPF_EAPROG_SEC("cgroup/sock_release",	BPF_PROG_TYPE_CGROUP_SOCK,
-						BPF_CGROUP_INET_SOCK_RELEASE),
-	BPF_APROG_SEC("cgroup/sock",		BPF_PROG_TYPE_CGROUP_SOCK,
-						BPF_CGROUP_INET_SOCK_CREATE),
-	BPF_EAPROG_SEC("cgroup/post_bind4",	BPF_PROG_TYPE_CGROUP_SOCK,
-						BPF_CGROUP_INET4_POST_BIND),
-	BPF_EAPROG_SEC("cgroup/post_bind6",	BPF_PROG_TYPE_CGROUP_SOCK,
-						BPF_CGROUP_INET6_POST_BIND),
-	BPF_APROG_SEC("cgroup/dev",		BPF_PROG_TYPE_CGROUP_DEVICE,
-						BPF_CGROUP_DEVICE),
-	BPF_APROG_SEC("sockops",		BPF_PROG_TYPE_SOCK_OPS,
-						BPF_CGROUP_SOCK_OPS),
-	BPF_APROG_SEC("sk_skb/stream_parser",	BPF_PROG_TYPE_SK_SKB,
-						BPF_SK_SKB_STREAM_PARSER),
-	BPF_APROG_SEC("sk_skb/stream_verdict",	BPF_PROG_TYPE_SK_SKB,
-						BPF_SK_SKB_STREAM_VERDICT),
+	SEC_DEF("cgroup/sock_create",	CGROUP_SOCK, BPF_CGROUP_INET_SOCK_CREATE, SEC_ATTACHABLE),
+	SEC_DEF("cgroup/sock_release",	CGROUP_SOCK, BPF_CGROUP_INET_SOCK_RELEASE, SEC_ATTACHABLE),
+	SEC_DEF("cgroup/sock",		CGROUP_SOCK, BPF_CGROUP_INET_SOCK_CREATE, SEC_ATTACHABLE_OPT),
+	SEC_DEF("cgroup/post_bind4",	CGROUP_SOCK, BPF_CGROUP_INET4_POST_BIND, SEC_ATTACHABLE),
+	SEC_DEF("cgroup/post_bind6",	CGROUP_SOCK, BPF_CGROUP_INET6_POST_BIND, SEC_ATTACHABLE),
+	SEC_DEF("cgroup/dev",		CGROUP_DEVICE, BPF_CGROUP_DEVICE, SEC_ATTACHABLE_OPT),
+	SEC_DEF("sockops",		SOCK_OPS, BPF_CGROUP_SOCK_OPS, SEC_ATTACHABLE_OPT),
+	SEC_DEF("sk_skb/stream_parser",	SK_SKB, BPF_SK_SKB_STREAM_PARSER, SEC_ATTACHABLE_OPT),
+	SEC_DEF("sk_skb/stream_verdict",SK_SKB, BPF_SK_SKB_STREAM_VERDICT, SEC_ATTACHABLE_OPT),
 	SEC_DEF("sk_skb",		SK_SKB, 0, SEC_NONE),
-	BPF_APROG_SEC("sk_msg",			BPF_PROG_TYPE_SK_MSG,
-						BPF_SK_MSG_VERDICT),
-	BPF_APROG_SEC("lirc_mode2",		BPF_PROG_TYPE_LIRC_MODE2,
-						BPF_LIRC_MODE2),
-	BPF_APROG_SEC("flow_dissector",		BPF_PROG_TYPE_FLOW_DISSECTOR,
-						BPF_FLOW_DISSECTOR),
-	BPF_EAPROG_SEC("cgroup/bind4",		BPF_PROG_TYPE_CGROUP_SOCK_ADDR,
-						BPF_CGROUP_INET4_BIND),
-	BPF_EAPROG_SEC("cgroup/bind6",		BPF_PROG_TYPE_CGROUP_SOCK_ADDR,
-						BPF_CGROUP_INET6_BIND),
-	BPF_EAPROG_SEC("cgroup/connect4",	BPF_PROG_TYPE_CGROUP_SOCK_ADDR,
-						BPF_CGROUP_INET4_CONNECT),
-	BPF_EAPROG_SEC("cgroup/connect6",	BPF_PROG_TYPE_CGROUP_SOCK_ADDR,
-						BPF_CGROUP_INET6_CONNECT),
-	BPF_EAPROG_SEC("cgroup/sendmsg4",	BPF_PROG_TYPE_CGROUP_SOCK_ADDR,
-						BPF_CGROUP_UDP4_SENDMSG),
-	BPF_EAPROG_SEC("cgroup/sendmsg6",	BPF_PROG_TYPE_CGROUP_SOCK_ADDR,
-						BPF_CGROUP_UDP6_SENDMSG),
-	BPF_EAPROG_SEC("cgroup/recvmsg4",	BPF_PROG_TYPE_CGROUP_SOCK_ADDR,
-						BPF_CGROUP_UDP4_RECVMSG),
-	BPF_EAPROG_SEC("cgroup/recvmsg6",	BPF_PROG_TYPE_CGROUP_SOCK_ADDR,
-						BPF_CGROUP_UDP6_RECVMSG),
-	BPF_EAPROG_SEC("cgroup/getpeername4",	BPF_PROG_TYPE_CGROUP_SOCK_ADDR,
-						BPF_CGROUP_INET4_GETPEERNAME),
-	BPF_EAPROG_SEC("cgroup/getpeername6",	BPF_PROG_TYPE_CGROUP_SOCK_ADDR,
-						BPF_CGROUP_INET6_GETPEERNAME),
-	BPF_EAPROG_SEC("cgroup/getsockname4",	BPF_PROG_TYPE_CGROUP_SOCK_ADDR,
-						BPF_CGROUP_INET4_GETSOCKNAME),
-	BPF_EAPROG_SEC("cgroup/getsockname6",	BPF_PROG_TYPE_CGROUP_SOCK_ADDR,
-						BPF_CGROUP_INET6_GETSOCKNAME),
-	BPF_EAPROG_SEC("cgroup/sysctl",		BPF_PROG_TYPE_CGROUP_SYSCTL,
-						BPF_CGROUP_SYSCTL),
-	BPF_EAPROG_SEC("cgroup/getsockopt",	BPF_PROG_TYPE_CGROUP_SOCKOPT,
-						BPF_CGROUP_GETSOCKOPT),
-	BPF_EAPROG_SEC("cgroup/setsockopt",	BPF_PROG_TYPE_CGROUP_SOCKOPT,
-						BPF_CGROUP_SETSOCKOPT),
+	SEC_DEF("sk_msg",		SK_MSG, BPF_SK_MSG_VERDICT, SEC_ATTACHABLE_OPT),
+	SEC_DEF("lirc_mode2",		LIRC_MODE2, BPF_LIRC_MODE2, SEC_ATTACHABLE_OPT),
+	SEC_DEF("flow_dissector",	FLOW_DISSECTOR, BPF_FLOW_DISSECTOR, SEC_ATTACHABLE_OPT),
+	SEC_DEF("cgroup/bind4",		CGROUP_SOCK_ADDR, BPF_CGROUP_INET4_BIND, SEC_ATTACHABLE),
+	SEC_DEF("cgroup/bind6",		CGROUP_SOCK_ADDR, BPF_CGROUP_INET6_BIND, SEC_ATTACHABLE),
+	SEC_DEF("cgroup/connect4",	CGROUP_SOCK_ADDR, BPF_CGROUP_INET4_CONNECT, SEC_ATTACHABLE),
+	SEC_DEF("cgroup/connect6",	CGROUP_SOCK_ADDR, BPF_CGROUP_INET6_CONNECT, SEC_ATTACHABLE),
+	SEC_DEF("cgroup/sendmsg4",	CGROUP_SOCK_ADDR, BPF_CGROUP_UDP4_SENDMSG, SEC_ATTACHABLE),
+	SEC_DEF("cgroup/sendmsg6",	CGROUP_SOCK_ADDR, BPF_CGROUP_UDP6_SENDMSG, SEC_ATTACHABLE),
+	SEC_DEF("cgroup/recvmsg4",	CGROUP_SOCK_ADDR, BPF_CGROUP_UDP4_RECVMSG, SEC_ATTACHABLE),
+	SEC_DEF("cgroup/recvmsg6",	CGROUP_SOCK_ADDR, BPF_CGROUP_UDP6_RECVMSG, SEC_ATTACHABLE),
+	SEC_DEF("cgroup/getpeername4",	CGROUP_SOCK_ADDR, BPF_CGROUP_INET4_GETPEERNAME, SEC_ATTACHABLE),
+	SEC_DEF("cgroup/getpeername6",	CGROUP_SOCK_ADDR, BPF_CGROUP_INET6_GETPEERNAME, SEC_ATTACHABLE),
+	SEC_DEF("cgroup/getsockname4",	CGROUP_SOCK_ADDR, BPF_CGROUP_INET4_GETSOCKNAME, SEC_ATTACHABLE),
+	SEC_DEF("cgroup/getsockname6",	CGROUP_SOCK_ADDR, BPF_CGROUP_INET6_GETSOCKNAME, SEC_ATTACHABLE),
+	SEC_DEF("cgroup/sysctl",	CGROUP_SYSCTL, BPF_CGROUP_SYSCTL, SEC_ATTACHABLE),
+	SEC_DEF("cgroup/getsockopt",	CGROUP_SOCKOPT, BPF_CGROUP_GETSOCKOPT, SEC_ATTACHABLE),
+	SEC_DEF("cgroup/setsockopt",	CGROUP_SOCKOPT, BPF_CGROUP_SETSOCKOPT, SEC_ATTACHABLE),
 	SEC_DEF("struct_ops",		STRUCT_OPS, 0, SEC_NONE),
-	BPF_EAPROG_SEC("sk_lookup/",		BPF_PROG_TYPE_SK_LOOKUP,
-						BPF_SK_LOOKUP),
+	SEC_DEF("sk_lookup/",		SK_LOOKUP, BPF_SK_LOOKUP, SEC_ATTACHABLE),
 };
 
-#undef BPF_PROG_SEC_IMPL
-#undef BPF_APROG_SEC
-#undef BPF_EAPROG_SEC
-#undef SEC_DEF
-
 #define MAX_TYPE_NAME_SIZE 32
 
 static const struct bpf_sec_def *find_sec_def(const char *sec_name)
-- 
cgit v1.2.3


From dd94d45cf0acb1d82748b17e1106b2c8b487b28b Mon Sep 17 00:00:00 2001
From: Andrii Nakryiko <andrii@kernel.org>
Date: Tue, 28 Sep 2021 09:19:45 -0700
Subject: libbpf: Add opt-in strict BPF program section name handling logic

Implement strict ELF section name handling for BPF programs. It utilizes
`libbpf_set_strict_mode()` framework and adds new flag: LIBBPF_STRICT_SEC_NAME.

If this flag is set, libbpf will enforce exact section name matching for
a lot of program types that previously allowed just partial prefix
match. E.g., if previously SEC("xdp_whatever_i_want") was allowed, now
in strict mode only SEC("xdp") will be accepted, which makes SEC("")
definitions cleaner and more structured. SEC() now won't be used as yet
another way to uniquely encode BPF program identifier (for that
C function name is better and is guaranteed to be unique within
bpf_object). Now SEC() is strictly BPF program type and, depending on
program type, extra load/attach parameter specification.

Libbpf completely supports multiple BPF programs in the same ELF
section, so multiple BPF programs of the same type/specification easily
co-exist together within the same bpf_object scope.

Additionally, a new (for now internal) convention is introduced: section
name that can be a stand-alone exact BPF program type specificator, but
also could have extra parameters after '/' delimiter. An example of such
section is "struct_ops", which can be specified by itself, but also
allows to specify the intended operation to be attached to, e.g.,
"struct_ops/dctcp_init". Note, that "struct_ops_some_op" is not allowed.
Such section definition is specified as "struct_ops+".

This change is part of libbpf 1.0 effort ([0], [1]).

  [0] Closes: https://github.com/libbpf/libbpf/issues/271
  [1] https://github.com/libbpf/libbpf/wiki/Libbpf:-the-road-to-v1.0#stricter-and-more-uniform-bpf-program-section-name-sec-handling

Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Dave Marchevsky <davemarchevsky@fb.com>
Link: https://lore.kernel.org/bpf/20210928161946.2512801-10-andrii@kernel.org
---
 tools/lib/bpf/libbpf.c        | 136 ++++++++++++++++++++++++++++--------------
 tools/lib/bpf/libbpf_legacy.h |   9 +++
 2 files changed, 99 insertions(+), 46 deletions(-)

(limited to 'tools/lib/bpf')

diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index 4ba67dff6b0d..3e1f6211b9b9 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -242,6 +242,8 @@ enum sec_def_flags {
 	SEC_ATTACH_BTF = 4,
 	/* BPF program type allows sleeping/blocking in kernel */
 	SEC_SLEEPABLE = 8,
+	/* allow non-strict prefix matching */
+	SEC_SLOPPY_PFX = 16,
 };
 
 struct bpf_sec_def {
@@ -7987,16 +7989,16 @@ static struct bpf_link *attach_lsm(const struct bpf_program *prog, long cookie);
 static struct bpf_link *attach_iter(const struct bpf_program *prog, long cookie);
 
 static const struct bpf_sec_def section_defs[] = {
-	SEC_DEF("socket",		SOCKET_FILTER, 0, SEC_NONE),
-	SEC_DEF("sk_reuseport/migrate",	SK_REUSEPORT, BPF_SK_REUSEPORT_SELECT_OR_MIGRATE, SEC_ATTACHABLE),
-	SEC_DEF("sk_reuseport",		SK_REUSEPORT, BPF_SK_REUSEPORT_SELECT, SEC_ATTACHABLE),
+	SEC_DEF("socket",		SOCKET_FILTER, 0, SEC_NONE | SEC_SLOPPY_PFX),
+	SEC_DEF("sk_reuseport/migrate",	SK_REUSEPORT, BPF_SK_REUSEPORT_SELECT_OR_MIGRATE, SEC_ATTACHABLE | SEC_SLOPPY_PFX),
+	SEC_DEF("sk_reuseport",		SK_REUSEPORT, BPF_SK_REUSEPORT_SELECT, SEC_ATTACHABLE | SEC_SLOPPY_PFX),
 	SEC_DEF("kprobe/",		KPROBE,	0, SEC_NONE, attach_kprobe),
 	SEC_DEF("uprobe/",		KPROBE,	0, SEC_NONE),
 	SEC_DEF("kretprobe/",		KPROBE, 0, SEC_NONE, attach_kprobe),
 	SEC_DEF("uretprobe/",		KPROBE, 0, SEC_NONE),
-	SEC_DEF("classifier",		SCHED_CLS, 0, SEC_NONE),
 	SEC_DEF("tc",			SCHED_CLS, 0, SEC_NONE),
-	SEC_DEF("action",		SCHED_ACT, 0, SEC_NONE),
+	SEC_DEF("classifier",		SCHED_CLS, 0, SEC_NONE | SEC_SLOPPY_PFX),
+	SEC_DEF("action",		SCHED_ACT, 0, SEC_NONE | SEC_SLOPPY_PFX),
 	SEC_DEF("tracepoint/",		TRACEPOINT, 0, SEC_NONE, attach_tp),
 	SEC_DEF("tp/",			TRACEPOINT, 0, SEC_NONE, attach_tp),
 	SEC_DEF("raw_tracepoint/",	RAW_TRACEPOINT, 0, SEC_NONE, attach_raw_tp),
@@ -8015,44 +8017,44 @@ static const struct bpf_sec_def section_defs[] = {
 	SEC_DEF("syscall",		SYSCALL, 0, SEC_SLEEPABLE),
 	SEC_DEF("xdp_devmap/",		XDP, BPF_XDP_DEVMAP, SEC_ATTACHABLE),
 	SEC_DEF("xdp_cpumap/",		XDP, BPF_XDP_CPUMAP, SEC_ATTACHABLE),
-	SEC_DEF("xdp",			XDP, BPF_XDP, SEC_ATTACHABLE_OPT),
-	SEC_DEF("perf_event",		PERF_EVENT, 0, SEC_NONE),
-	SEC_DEF("lwt_in",		LWT_IN, 0, SEC_NONE),
-	SEC_DEF("lwt_out",		LWT_OUT, 0, SEC_NONE),
-	SEC_DEF("lwt_xmit",		LWT_XMIT, 0, SEC_NONE),
-	SEC_DEF("lwt_seg6local",	LWT_SEG6LOCAL, 0, SEC_NONE),
-	SEC_DEF("cgroup_skb/ingress",	CGROUP_SKB, BPF_CGROUP_INET_INGRESS, SEC_ATTACHABLE_OPT),
-	SEC_DEF("cgroup_skb/egress",	CGROUP_SKB, BPF_CGROUP_INET_EGRESS, SEC_ATTACHABLE_OPT),
-	SEC_DEF("cgroup/skb",		CGROUP_SKB, 0, SEC_NONE),
-	SEC_DEF("cgroup/sock_create",	CGROUP_SOCK, BPF_CGROUP_INET_SOCK_CREATE, SEC_ATTACHABLE),
-	SEC_DEF("cgroup/sock_release",	CGROUP_SOCK, BPF_CGROUP_INET_SOCK_RELEASE, SEC_ATTACHABLE),
-	SEC_DEF("cgroup/sock",		CGROUP_SOCK, BPF_CGROUP_INET_SOCK_CREATE, SEC_ATTACHABLE_OPT),
-	SEC_DEF("cgroup/post_bind4",	CGROUP_SOCK, BPF_CGROUP_INET4_POST_BIND, SEC_ATTACHABLE),
-	SEC_DEF("cgroup/post_bind6",	CGROUP_SOCK, BPF_CGROUP_INET6_POST_BIND, SEC_ATTACHABLE),
-	SEC_DEF("cgroup/dev",		CGROUP_DEVICE, BPF_CGROUP_DEVICE, SEC_ATTACHABLE_OPT),
-	SEC_DEF("sockops",		SOCK_OPS, BPF_CGROUP_SOCK_OPS, SEC_ATTACHABLE_OPT),
-	SEC_DEF("sk_skb/stream_parser",	SK_SKB, BPF_SK_SKB_STREAM_PARSER, SEC_ATTACHABLE_OPT),
-	SEC_DEF("sk_skb/stream_verdict",SK_SKB, BPF_SK_SKB_STREAM_VERDICT, SEC_ATTACHABLE_OPT),
-	SEC_DEF("sk_skb",		SK_SKB, 0, SEC_NONE),
-	SEC_DEF("sk_msg",		SK_MSG, BPF_SK_MSG_VERDICT, SEC_ATTACHABLE_OPT),
-	SEC_DEF("lirc_mode2",		LIRC_MODE2, BPF_LIRC_MODE2, SEC_ATTACHABLE_OPT),
-	SEC_DEF("flow_dissector",	FLOW_DISSECTOR, BPF_FLOW_DISSECTOR, SEC_ATTACHABLE_OPT),
-	SEC_DEF("cgroup/bind4",		CGROUP_SOCK_ADDR, BPF_CGROUP_INET4_BIND, SEC_ATTACHABLE),
-	SEC_DEF("cgroup/bind6",		CGROUP_SOCK_ADDR, BPF_CGROUP_INET6_BIND, SEC_ATTACHABLE),
-	SEC_DEF("cgroup/connect4",	CGROUP_SOCK_ADDR, BPF_CGROUP_INET4_CONNECT, SEC_ATTACHABLE),
-	SEC_DEF("cgroup/connect6",	CGROUP_SOCK_ADDR, BPF_CGROUP_INET6_CONNECT, SEC_ATTACHABLE),
-	SEC_DEF("cgroup/sendmsg4",	CGROUP_SOCK_ADDR, BPF_CGROUP_UDP4_SENDMSG, SEC_ATTACHABLE),
-	SEC_DEF("cgroup/sendmsg6",	CGROUP_SOCK_ADDR, BPF_CGROUP_UDP6_SENDMSG, SEC_ATTACHABLE),
-	SEC_DEF("cgroup/recvmsg4",	CGROUP_SOCK_ADDR, BPF_CGROUP_UDP4_RECVMSG, SEC_ATTACHABLE),
-	SEC_DEF("cgroup/recvmsg6",	CGROUP_SOCK_ADDR, BPF_CGROUP_UDP6_RECVMSG, SEC_ATTACHABLE),
-	SEC_DEF("cgroup/getpeername4",	CGROUP_SOCK_ADDR, BPF_CGROUP_INET4_GETPEERNAME, SEC_ATTACHABLE),
-	SEC_DEF("cgroup/getpeername6",	CGROUP_SOCK_ADDR, BPF_CGROUP_INET6_GETPEERNAME, SEC_ATTACHABLE),
-	SEC_DEF("cgroup/getsockname4",	CGROUP_SOCK_ADDR, BPF_CGROUP_INET4_GETSOCKNAME, SEC_ATTACHABLE),
-	SEC_DEF("cgroup/getsockname6",	CGROUP_SOCK_ADDR, BPF_CGROUP_INET6_GETSOCKNAME, SEC_ATTACHABLE),
-	SEC_DEF("cgroup/sysctl",	CGROUP_SYSCTL, BPF_CGROUP_SYSCTL, SEC_ATTACHABLE),
-	SEC_DEF("cgroup/getsockopt",	CGROUP_SOCKOPT, BPF_CGROUP_GETSOCKOPT, SEC_ATTACHABLE),
-	SEC_DEF("cgroup/setsockopt",	CGROUP_SOCKOPT, BPF_CGROUP_SETSOCKOPT, SEC_ATTACHABLE),
-	SEC_DEF("struct_ops",		STRUCT_OPS, 0, SEC_NONE),
+	SEC_DEF("xdp",			XDP, BPF_XDP, SEC_ATTACHABLE_OPT | SEC_SLOPPY_PFX),
+	SEC_DEF("perf_event",		PERF_EVENT, 0, SEC_NONE | SEC_SLOPPY_PFX),
+	SEC_DEF("lwt_in",		LWT_IN, 0, SEC_NONE | SEC_SLOPPY_PFX),
+	SEC_DEF("lwt_out",		LWT_OUT, 0, SEC_NONE | SEC_SLOPPY_PFX),
+	SEC_DEF("lwt_xmit",		LWT_XMIT, 0, SEC_NONE | SEC_SLOPPY_PFX),
+	SEC_DEF("lwt_seg6local",	LWT_SEG6LOCAL, 0, SEC_NONE | SEC_SLOPPY_PFX),
+	SEC_DEF("cgroup_skb/ingress",	CGROUP_SKB, BPF_CGROUP_INET_INGRESS, SEC_ATTACHABLE_OPT | SEC_SLOPPY_PFX),
+	SEC_DEF("cgroup_skb/egress",	CGROUP_SKB, BPF_CGROUP_INET_EGRESS, SEC_ATTACHABLE_OPT | SEC_SLOPPY_PFX),
+	SEC_DEF("cgroup/skb",		CGROUP_SKB, 0, SEC_NONE | SEC_SLOPPY_PFX),
+	SEC_DEF("cgroup/sock_create",	CGROUP_SOCK, BPF_CGROUP_INET_SOCK_CREATE, SEC_ATTACHABLE | SEC_SLOPPY_PFX),
+	SEC_DEF("cgroup/sock_release",	CGROUP_SOCK, BPF_CGROUP_INET_SOCK_RELEASE, SEC_ATTACHABLE | SEC_SLOPPY_PFX),
+	SEC_DEF("cgroup/sock",		CGROUP_SOCK, BPF_CGROUP_INET_SOCK_CREATE, SEC_ATTACHABLE_OPT | SEC_SLOPPY_PFX),
+	SEC_DEF("cgroup/post_bind4",	CGROUP_SOCK, BPF_CGROUP_INET4_POST_BIND, SEC_ATTACHABLE | SEC_SLOPPY_PFX),
+	SEC_DEF("cgroup/post_bind6",	CGROUP_SOCK, BPF_CGROUP_INET6_POST_BIND, SEC_ATTACHABLE | SEC_SLOPPY_PFX),
+	SEC_DEF("cgroup/dev",		CGROUP_DEVICE, BPF_CGROUP_DEVICE, SEC_ATTACHABLE_OPT | SEC_SLOPPY_PFX),
+	SEC_DEF("sockops",		SOCK_OPS, BPF_CGROUP_SOCK_OPS, SEC_ATTACHABLE_OPT | SEC_SLOPPY_PFX),
+	SEC_DEF("sk_skb/stream_parser",	SK_SKB, BPF_SK_SKB_STREAM_PARSER, SEC_ATTACHABLE_OPT | SEC_SLOPPY_PFX),
+	SEC_DEF("sk_skb/stream_verdict",SK_SKB, BPF_SK_SKB_STREAM_VERDICT, SEC_ATTACHABLE_OPT | SEC_SLOPPY_PFX),
+	SEC_DEF("sk_skb",		SK_SKB, 0, SEC_NONE | SEC_SLOPPY_PFX),
+	SEC_DEF("sk_msg",		SK_MSG, BPF_SK_MSG_VERDICT, SEC_ATTACHABLE_OPT | SEC_SLOPPY_PFX),
+	SEC_DEF("lirc_mode2",		LIRC_MODE2, BPF_LIRC_MODE2, SEC_ATTACHABLE_OPT | SEC_SLOPPY_PFX),
+	SEC_DEF("flow_dissector",	FLOW_DISSECTOR, BPF_FLOW_DISSECTOR, SEC_ATTACHABLE_OPT | SEC_SLOPPY_PFX),
+	SEC_DEF("cgroup/bind4",		CGROUP_SOCK_ADDR, BPF_CGROUP_INET4_BIND, SEC_ATTACHABLE | SEC_SLOPPY_PFX),
+	SEC_DEF("cgroup/bind6",		CGROUP_SOCK_ADDR, BPF_CGROUP_INET6_BIND, SEC_ATTACHABLE | SEC_SLOPPY_PFX),
+	SEC_DEF("cgroup/connect4",	CGROUP_SOCK_ADDR, BPF_CGROUP_INET4_CONNECT, SEC_ATTACHABLE | SEC_SLOPPY_PFX),
+	SEC_DEF("cgroup/connect6",	CGROUP_SOCK_ADDR, BPF_CGROUP_INET6_CONNECT, SEC_ATTACHABLE | SEC_SLOPPY_PFX),
+	SEC_DEF("cgroup/sendmsg4",	CGROUP_SOCK_ADDR, BPF_CGROUP_UDP4_SENDMSG, SEC_ATTACHABLE | SEC_SLOPPY_PFX),
+	SEC_DEF("cgroup/sendmsg6",	CGROUP_SOCK_ADDR, BPF_CGROUP_UDP6_SENDMSG, SEC_ATTACHABLE | SEC_SLOPPY_PFX),
+	SEC_DEF("cgroup/recvmsg4",	CGROUP_SOCK_ADDR, BPF_CGROUP_UDP4_RECVMSG, SEC_ATTACHABLE | SEC_SLOPPY_PFX),
+	SEC_DEF("cgroup/recvmsg6",	CGROUP_SOCK_ADDR, BPF_CGROUP_UDP6_RECVMSG, SEC_ATTACHABLE | SEC_SLOPPY_PFX),
+	SEC_DEF("cgroup/getpeername4",	CGROUP_SOCK_ADDR, BPF_CGROUP_INET4_GETPEERNAME, SEC_ATTACHABLE | SEC_SLOPPY_PFX),
+	SEC_DEF("cgroup/getpeername6",	CGROUP_SOCK_ADDR, BPF_CGROUP_INET6_GETPEERNAME, SEC_ATTACHABLE | SEC_SLOPPY_PFX),
+	SEC_DEF("cgroup/getsockname4",	CGROUP_SOCK_ADDR, BPF_CGROUP_INET4_GETSOCKNAME, SEC_ATTACHABLE | SEC_SLOPPY_PFX),
+	SEC_DEF("cgroup/getsockname6",	CGROUP_SOCK_ADDR, BPF_CGROUP_INET6_GETSOCKNAME, SEC_ATTACHABLE | SEC_SLOPPY_PFX),
+	SEC_DEF("cgroup/sysctl",	CGROUP_SYSCTL, BPF_CGROUP_SYSCTL, SEC_ATTACHABLE | SEC_SLOPPY_PFX),
+	SEC_DEF("cgroup/getsockopt",	CGROUP_SOCKOPT, BPF_CGROUP_GETSOCKOPT, SEC_ATTACHABLE | SEC_SLOPPY_PFX),
+	SEC_DEF("cgroup/setsockopt",	CGROUP_SOCKOPT, BPF_CGROUP_SETSOCKOPT, SEC_ATTACHABLE | SEC_SLOPPY_PFX),
+	SEC_DEF("struct_ops+",		STRUCT_OPS, 0, SEC_NONE),
 	SEC_DEF("sk_lookup/",		SK_LOOKUP, BPF_SK_LOOKUP, SEC_ATTACHABLE),
 };
 
@@ -8060,11 +8062,53 @@ static const struct bpf_sec_def section_defs[] = {
 
 static const struct bpf_sec_def *find_sec_def(const char *sec_name)
 {
-	int i, n = ARRAY_SIZE(section_defs);
+	const struct bpf_sec_def *sec_def;
+	enum sec_def_flags sec_flags;
+	int i, n = ARRAY_SIZE(section_defs), len;
+	bool strict = libbpf_mode & LIBBPF_STRICT_SEC_NAME;
 
 	for (i = 0; i < n; i++) {
-		if (str_has_pfx(sec_name, section_defs[i].sec))
-			return &section_defs[i];
+		sec_def = &section_defs[i];
+		sec_flags = sec_def->cookie;
+		len = strlen(sec_def->sec);
+
+		/* "type/" always has to have proper SEC("type/extras") form */
+		if (sec_def->sec[len - 1] == '/') {
+			if (str_has_pfx(sec_name, sec_def->sec))
+				return sec_def;
+			continue;
+		}
+
+		/* "type+" means it can be either exact SEC("type") or
+		 * well-formed SEC("type/extras") with proper '/' separator
+		 */
+		if (sec_def->sec[len - 1] == '+') {
+			len--;
+			/* not even a prefix */
+			if (strncmp(sec_name, sec_def->sec, len) != 0)
+				continue;
+			/* exact match or has '/' separator */
+			if (sec_name[len] == '\0' || sec_name[len] == '/')
+				return sec_def;
+			continue;
+		}
+
+		/* SEC_SLOPPY_PFX definitions are allowed to be just prefix
+		 * matches, unless strict section name mode
+		 * (LIBBPF_STRICT_SEC_NAME) is enabled, in which case the
+		 * match has to be exact.
+		 */
+		if ((sec_flags & SEC_SLOPPY_PFX) && !strict)  {
+			if (str_has_pfx(sec_name, sec_def->sec))
+				return sec_def;
+			continue;
+		}
+
+		/* Definitions not marked SEC_SLOPPY_PFX (e.g.,
+		 * SEC("syscall")) are exact matches in both modes.
+		 */
+		if (strcmp(sec_name, sec_def->sec) == 0)
+			return sec_def;
 	}
 	return NULL;
 }
diff --git a/tools/lib/bpf/libbpf_legacy.h b/tools/lib/bpf/libbpf_legacy.h
index df0d03dcffab..74e6f860f703 100644
--- a/tools/lib/bpf/libbpf_legacy.h
+++ b/tools/lib/bpf/libbpf_legacy.h
@@ -46,6 +46,15 @@ enum libbpf_strict_mode {
 	 */
 	LIBBPF_STRICT_DIRECT_ERRS = 0x02,
 
+	/*
+	 * Enforce strict BPF program section (SEC()) names.
+	 * E.g., while prefiously SEC("xdp_whatever") or SEC("perf_event_blah") were
+	 * allowed, with LIBBPF_STRICT_SEC_PREFIX this will become
+	 * unrecognized by libbpf and would have to be just SEC("xdp") and
+	 * SEC("xdp") and SEC("perf_event").
+	 */
+	LIBBPF_STRICT_SEC_NAME = 0x04,
+
 	__LIBBPF_STRICT_LAST,
 };
 
-- 
cgit v1.2.3


From 7c80c87ad56a05ec56069c3f5d7e60b5b1eb19b4 Mon Sep 17 00:00:00 2001
From: Andrii Nakryiko <andrii@kernel.org>
Date: Tue, 28 Sep 2021 09:19:46 -0700
Subject: selftests/bpf: Switch sk_lookup selftests to strict SEC("sk_lookup")
 use

Update "sk_lookup/" definition to be a stand-alone type specifier,
with backwards-compatible prefix match logic in non-libbpf-1.0 mode.

Currently in selftests all the "sk_lookup/<whatever>" uses just use
<whatever> for duplicated unique name encoding, which is redundant as
BPF program's name (C function name) uniquely and descriptively
identifies the intended use for such BPF programs.

With libbpf's SEC_DEF("sk_lookup") definition updated, switch existing
sk_lookup programs to use "unqualified" SEC("sk_lookup") section names,
with no random text after it.

Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Dave Marchevsky <davemarchevsky@fb.com>
Link: https://lore.kernel.org/bpf/20210928161946.2512801-11-andrii@kernel.org
---
 tools/lib/bpf/libbpf.c                             |  2 +-
 tools/testing/selftests/bpf/progs/test_sk_lookup.c | 38 +++++++++++-----------
 2 files changed, 20 insertions(+), 20 deletions(-)

(limited to 'tools/lib/bpf')

diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index 3e1f6211b9b9..1c859b32968d 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -8055,7 +8055,7 @@ static const struct bpf_sec_def section_defs[] = {
 	SEC_DEF("cgroup/getsockopt",	CGROUP_SOCKOPT, BPF_CGROUP_GETSOCKOPT, SEC_ATTACHABLE | SEC_SLOPPY_PFX),
 	SEC_DEF("cgroup/setsockopt",	CGROUP_SOCKOPT, BPF_CGROUP_SETSOCKOPT, SEC_ATTACHABLE | SEC_SLOPPY_PFX),
 	SEC_DEF("struct_ops+",		STRUCT_OPS, 0, SEC_NONE),
-	SEC_DEF("sk_lookup/",		SK_LOOKUP, BPF_SK_LOOKUP, SEC_ATTACHABLE),
+	SEC_DEF("sk_lookup",		SK_LOOKUP, BPF_SK_LOOKUP, SEC_ATTACHABLE | SEC_SLOPPY_PFX),
 };
 
 #define MAX_TYPE_NAME_SIZE 32
diff --git a/tools/testing/selftests/bpf/progs/test_sk_lookup.c b/tools/testing/selftests/bpf/progs/test_sk_lookup.c
index 6c4d32c56765..48534d810391 100644
--- a/tools/testing/selftests/bpf/progs/test_sk_lookup.c
+++ b/tools/testing/selftests/bpf/progs/test_sk_lookup.c
@@ -72,13 +72,13 @@ static const __u16 DST_PORT = 7007; /* Host byte order */
 static const __u32 DST_IP4 = IP4(127, 0, 0, 1);
 static const __u32 DST_IP6[] = IP6(0xfd000000, 0x0, 0x0, 0x00000001);
 
-SEC("sk_lookup/lookup_pass")
+SEC("sk_lookup")
 int lookup_pass(struct bpf_sk_lookup *ctx)
 {
 	return SK_PASS;
 }
 
-SEC("sk_lookup/lookup_drop")
+SEC("sk_lookup")
 int lookup_drop(struct bpf_sk_lookup *ctx)
 {
 	return SK_DROP;
@@ -97,7 +97,7 @@ int reuseport_drop(struct sk_reuseport_md *ctx)
 }
 
 /* Redirect packets destined for port DST_PORT to socket at redir_map[0]. */
-SEC("sk_lookup/redir_port")
+SEC("sk_lookup")
 int redir_port(struct bpf_sk_lookup *ctx)
 {
 	struct bpf_sock *sk;
@@ -116,7 +116,7 @@ int redir_port(struct bpf_sk_lookup *ctx)
 }
 
 /* Redirect packets destined for DST_IP4 address to socket at redir_map[0]. */
-SEC("sk_lookup/redir_ip4")
+SEC("sk_lookup")
 int redir_ip4(struct bpf_sk_lookup *ctx)
 {
 	struct bpf_sock *sk;
@@ -139,7 +139,7 @@ int redir_ip4(struct bpf_sk_lookup *ctx)
 }
 
 /* Redirect packets destined for DST_IP6 address to socket at redir_map[0]. */
-SEC("sk_lookup/redir_ip6")
+SEC("sk_lookup")
 int redir_ip6(struct bpf_sk_lookup *ctx)
 {
 	struct bpf_sock *sk;
@@ -164,7 +164,7 @@ int redir_ip6(struct bpf_sk_lookup *ctx)
 	return err ? SK_DROP : SK_PASS;
 }
 
-SEC("sk_lookup/select_sock_a")
+SEC("sk_lookup")
 int select_sock_a(struct bpf_sk_lookup *ctx)
 {
 	struct bpf_sock *sk;
@@ -179,7 +179,7 @@ int select_sock_a(struct bpf_sk_lookup *ctx)
 	return err ? SK_DROP : SK_PASS;
 }
 
-SEC("sk_lookup/select_sock_a_no_reuseport")
+SEC("sk_lookup")
 int select_sock_a_no_reuseport(struct bpf_sk_lookup *ctx)
 {
 	struct bpf_sock *sk;
@@ -205,7 +205,7 @@ int select_sock_b(struct sk_reuseport_md *ctx)
 }
 
 /* Check that bpf_sk_assign() returns -EEXIST if socket already selected. */
-SEC("sk_lookup/sk_assign_eexist")
+SEC("sk_lookup")
 int sk_assign_eexist(struct bpf_sk_lookup *ctx)
 {
 	struct bpf_sock *sk;
@@ -238,7 +238,7 @@ out:
 }
 
 /* Check that bpf_sk_assign(BPF_SK_LOOKUP_F_REPLACE) can override selection. */
-SEC("sk_lookup/sk_assign_replace_flag")
+SEC("sk_lookup")
 int sk_assign_replace_flag(struct bpf_sk_lookup *ctx)
 {
 	struct bpf_sock *sk;
@@ -270,7 +270,7 @@ out:
 }
 
 /* Check that bpf_sk_assign(sk=NULL) is accepted. */
-SEC("sk_lookup/sk_assign_null")
+SEC("sk_lookup")
 int sk_assign_null(struct bpf_sk_lookup *ctx)
 {
 	struct bpf_sock *sk = NULL;
@@ -313,7 +313,7 @@ out:
 }
 
 /* Check that selected sk is accessible through context. */
-SEC("sk_lookup/access_ctx_sk")
+SEC("sk_lookup")
 int access_ctx_sk(struct bpf_sk_lookup *ctx)
 {
 	struct bpf_sock *sk1 = NULL, *sk2 = NULL;
@@ -379,7 +379,7 @@ out:
  * are not covered because they give bogus results, that is the
  * verifier ignores the offset.
  */
-SEC("sk_lookup/ctx_narrow_access")
+SEC("sk_lookup")
 int ctx_narrow_access(struct bpf_sk_lookup *ctx)
 {
 	struct bpf_sock *sk;
@@ -553,7 +553,7 @@ int ctx_narrow_access(struct bpf_sk_lookup *ctx)
 }
 
 /* Check that sk_assign rejects SERVER_A socket with -ESOCKNOSUPPORT */
-SEC("sk_lookup/sk_assign_esocknosupport")
+SEC("sk_lookup")
 int sk_assign_esocknosupport(struct bpf_sk_lookup *ctx)
 {
 	struct bpf_sock *sk;
@@ -578,28 +578,28 @@ out:
 	return ret;
 }
 
-SEC("sk_lookup/multi_prog_pass1")
+SEC("sk_lookup")
 int multi_prog_pass1(struct bpf_sk_lookup *ctx)
 {
 	bpf_map_update_elem(&run_map, &KEY_PROG1, &PROG_DONE, BPF_ANY);
 	return SK_PASS;
 }
 
-SEC("sk_lookup/multi_prog_pass2")
+SEC("sk_lookup")
 int multi_prog_pass2(struct bpf_sk_lookup *ctx)
 {
 	bpf_map_update_elem(&run_map, &KEY_PROG2, &PROG_DONE, BPF_ANY);
 	return SK_PASS;
 }
 
-SEC("sk_lookup/multi_prog_drop1")
+SEC("sk_lookup")
 int multi_prog_drop1(struct bpf_sk_lookup *ctx)
 {
 	bpf_map_update_elem(&run_map, &KEY_PROG1, &PROG_DONE, BPF_ANY);
 	return SK_DROP;
 }
 
-SEC("sk_lookup/multi_prog_drop2")
+SEC("sk_lookup")
 int multi_prog_drop2(struct bpf_sk_lookup *ctx)
 {
 	bpf_map_update_elem(&run_map, &KEY_PROG2, &PROG_DONE, BPF_ANY);
@@ -623,7 +623,7 @@ static __always_inline int select_server_a(struct bpf_sk_lookup *ctx)
 	return SK_PASS;
 }
 
-SEC("sk_lookup/multi_prog_redir1")
+SEC("sk_lookup")
 int multi_prog_redir1(struct bpf_sk_lookup *ctx)
 {
 	int ret;
@@ -633,7 +633,7 @@ int multi_prog_redir1(struct bpf_sk_lookup *ctx)
 	return SK_PASS;
 }
 
-SEC("sk_lookup/multi_prog_redir2")
+SEC("sk_lookup")
 int multi_prog_redir2(struct bpf_sk_lookup *ctx)
 {
 	int ret;
-- 
cgit v1.2.3


From 66fe33241726d1f872e55d95a35c063d58602ae1 Mon Sep 17 00:00:00 2001
From: Alexei Starovoitov <ast@kernel.org>
Date: Mon, 27 Sep 2021 20:29:37 +0530
Subject: libbpf: Make gen_loader data aligned.

Align gen_loader data to 8 byte boundary to make sure union bpf_attr,
bpf_insns and other structs are aligned.

Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20210927145941.1383001-9-memxor@gmail.com
---
 tools/lib/bpf/gen_loader.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

(limited to 'tools/lib/bpf')

diff --git a/tools/lib/bpf/gen_loader.c b/tools/lib/bpf/gen_loader.c
index 8df718a6b142..80087b13877f 100644
--- a/tools/lib/bpf/gen_loader.c
+++ b/tools/lib/bpf/gen_loader.c
@@ -5,6 +5,7 @@
 #include <string.h>
 #include <errno.h>
 #include <linux/filter.h>
+#include <sys/param.h>
 #include "btf.h"
 #include "bpf.h"
 #include "libbpf.h"
@@ -135,13 +136,17 @@ void bpf_gen__init(struct bpf_gen *gen, int log_level)
 
 static int add_data(struct bpf_gen *gen, const void *data, __u32 size)
 {
+	__u32 size8 = roundup(size, 8);
+	__u64 zero = 0;
 	void *prev;
 
-	if (realloc_data_buf(gen, size))
+	if (realloc_data_buf(gen, size8))
 		return 0;
 	prev = gen->data_cur;
 	memcpy(gen->data_cur, data, size);
 	gen->data_cur += size;
+	memcpy(gen->data_cur, &zero, size8 - size);
+	gen->data_cur += size8 - size;
 	return prev - gen->data_start;
 }
 
-- 
cgit v1.2.3


From 161ecd537948a7003129889b04a3a0858687bc70 Mon Sep 17 00:00:00 2001
From: Toke Høiland-Jørgensen <toke@redhat.com>
Date: Wed, 29 Sep 2021 23:38:37 +0200
Subject: libbpf: Properly ignore STT_SECTION symbols in legacy map definitions
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

The previous patch to ignore STT_SECTION symbols only added the ignore
condition in one of them. This fails if there's more than one map
definition in the 'maps' section, because the subsequent modulus check will
fail, resulting in error messages like:

libbpf: elf: unable to determine legacy map definition size in ./xdpdump_xdp.o

Fix this by also ignoring STT_SECTION in the first loop.

Fixes: c3e8c44a9063 ("libbpf: Ignore STT_SECTION symbols in 'maps' section")
Signed-off-by: Toke Høiland-Jørgensen <toke@redhat.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20210929213837.832449-1-toke@redhat.com
---
 tools/lib/bpf/libbpf.c | 2 ++
 1 file changed, 2 insertions(+)

(limited to 'tools/lib/bpf')

diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index 1c859b32968d..7544d7d09160 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -1868,6 +1868,8 @@ static int bpf_object__init_user_maps(struct bpf_object *obj, bool strict)
 			continue;
 		if (sym.st_shndx != obj->efile.maps_shndx)
 			continue;
+		if (GELF_ST_TYPE(sym.st_info) == STT_SECTION)
+			continue;
 		nr_maps++;
 	}
 	/* Assume equally sized map definitions */
-- 
cgit v1.2.3


From e68ac0082787f4e8ee6ae5b19076ec7709ce715b Mon Sep 17 00:00:00 2001
From: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Date: Mon, 27 Sep 2021 20:29:39 +0530
Subject: libbpf: Fix skel_internal.h to set errno on loader retval < 0

When the loader indicates an internal error (result of a checked bpf
system call), it returns the result in attr.test.retval. However, tests
that rely on ASSERT_OK_PTR on NULL (returned from light skeleton) may
miss that NULL denotes an error if errno is set to 0. This would result
in skel pointer being NULL, while ASSERT_OK_PTR returning 1, leading to
a SEGV on dereference of skel, because libbpf_get_error relies on the
assumption that errno is always set in case of error for ptr == NULL.

In particular, this was observed for the ksyms_module test. When
executed using `./test_progs -t ksyms`, prior tests manipulated errno
and the test didn't crash when it failed at ksyms_module load, while
using `./test_progs -t ksyms_module` crashed due to errno being
untouched.

Fixes: 67234743736a (libbpf: Generate loader program out of BPF ELF file.)
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20210927145941.1383001-11-memxor@gmail.com
---
 tools/lib/bpf/skel_internal.h | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

(limited to 'tools/lib/bpf')

diff --git a/tools/lib/bpf/skel_internal.h b/tools/lib/bpf/skel_internal.h
index b22b50c1b173..9cf66702fa8d 100644
--- a/tools/lib/bpf/skel_internal.h
+++ b/tools/lib/bpf/skel_internal.h
@@ -105,10 +105,12 @@ static inline int bpf_load_and_run(struct bpf_load_and_run_opts *opts)
 	err = skel_sys_bpf(BPF_PROG_RUN, &attr, sizeof(attr));
 	if (err < 0 || (int)attr.test.retval < 0) {
 		opts->errstr = "failed to execute loader prog";
-		if (err < 0)
+		if (err < 0) {
 			err = -errno;
-		else
+		} else {
 			err = (int)attr.test.retval;
+			errno = -err;
+		}
 		goto out;
 	}
 	err = 0;
-- 
cgit v1.2.3


From f731052325efc3726577feb743c7495f880ae07d Mon Sep 17 00:00:00 2001
From: Hengqi Chen <hengqi.chen@gmail.com>
Date: Fri, 1 Oct 2021 00:14:55 +0800
Subject: libbpf: Support uniform BTF-defined key/value specification across
 all BPF maps

A bunch of BPF maps do not support specifying BTF types for key and value.
This is non-uniform and inconvenient[0]. Currently, libbpf uses a retry
logic which removes BTF type IDs when BPF map creation failed. Instead
of retrying, this commit recognizes those specialized maps and removes
BTF type IDs when creating BPF map.

  [0] Closes: https://github.com/libbpf/libbpf/issues/355

Signed-off-by: Hengqi Chen <hengqi.chen@gmail.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20210930161456.3444544-2-hengqi.chen@gmail.com
---
 tools/lib/bpf/libbpf.c | 24 ++++++++++++++++++++++++
 1 file changed, 24 insertions(+)

(limited to 'tools/lib/bpf')

diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index 7544d7d09160..e23f1b6b9402 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -4669,6 +4669,30 @@ static int bpf_object__create_map(struct bpf_object *obj, struct bpf_map *map, b
 			create_attr.inner_map_fd = map->inner_map_fd;
 	}
 
+	switch (def->type) {
+	case BPF_MAP_TYPE_PERF_EVENT_ARRAY:
+	case BPF_MAP_TYPE_CGROUP_ARRAY:
+	case BPF_MAP_TYPE_STACK_TRACE:
+	case BPF_MAP_TYPE_ARRAY_OF_MAPS:
+	case BPF_MAP_TYPE_HASH_OF_MAPS:
+	case BPF_MAP_TYPE_DEVMAP:
+	case BPF_MAP_TYPE_DEVMAP_HASH:
+	case BPF_MAP_TYPE_CPUMAP:
+	case BPF_MAP_TYPE_XSKMAP:
+	case BPF_MAP_TYPE_SOCKMAP:
+	case BPF_MAP_TYPE_SOCKHASH:
+	case BPF_MAP_TYPE_QUEUE:
+	case BPF_MAP_TYPE_STACK:
+	case BPF_MAP_TYPE_RINGBUF:
+		create_attr.btf_fd = 0;
+		create_attr.btf_key_type_id = 0;
+		create_attr.btf_value_type_id = 0;
+		map->btf_key_type_id = 0;
+		map->btf_value_type_id = 0;
+	default:
+		break;
+	}
+
 	if (obj->gen_loader) {
 		bpf_gen__map_create(obj->gen_loader, &create_attr, is_inner ? -1 : map - obj->maps);
 		/* Pretend to have valid FD to pass various fd >= 0 checks.
-- 
cgit v1.2.3