kernel/linux.git/tools/bpf/bpftool/struct_ops.c, branch v6.19.11

bpftool: Mount bpffs on provided dir instead of parent dir

2024-04-04T22:37:12+00:00

When pinning programs/objects under PATH (eg: during "bpftool prog loadall") the bpffs is mounted on the parent dir of PATH in the following situations: - the given dir exists but it is not bpffs. - the given dir doesn't exist and the parent dir is not bpffs. Mounting on the parent dir can also have the unintentional side- effect of hiding other files located under the parent dir. If the given dir exists but is not bpffs, then the bpffs should be mounted on the given dir and not its parent dir. Similarly, if the given dir doesn't exist and its parent dir is not bpffs, then the given dir should be created and the bpffs should be mounted on this new dir. Fixes: 2a36c26fe3b8 ("bpftool: Support bpffs mountpoint as pin path for prog loadall") Signed-off-by: Sahil Siddiq Signed-off-by: Andrii Nakryiko Link: https://lore.kernel.org/bpf/2da44d24-74ae-a564-1764-afccf395eeec@isovalent.com/T/#t Link: https://lore.kernel.org/bpf/20240404192219.52373-1-icegambit91@gmail.com Closes: https://github.com/libbpf/bpftool/issues/100 Changes since v1: - Split "mount_bpffs_for_pin" into two functions. This is done to improve maintainability and readability. Changes since v2: - mount_bpffs_for_pin: rename to "create_and_mount_bpffs_dir". - mount_bpffs_given_file: rename to "mount_bpffs_given_file". - create_and_mount_bpffs_dir: - introduce "dir_exists" boolean. - remove new dir if "mnt_fs" fails. - improve error handling and error messages. Changes since v3: - Rectify function name. - Improve error messages and formatting. - mount_bpffs_for_file: - Check if dir exists before block_mount check. Changes since v4: - Use strdup instead of strcpy. - create_and_mount_bpffs_dir: - Use S_IRWXU instead of 0700. - Improve error handling and formatting.

bpftool: Wrap struct_ops dump in an array

2023-10-19T14:30:15+00:00

When dumping a struct_ops, 2 dictionaries are emitted. When using `name`, they were already wrapped in an array, but not when using `id`. Causing `jq` to fail at parsing the payload as it reached the comma following the first dict. This change wraps those dictionaries in an array so valid json is emitted. Before, jq fails to parse the output: ``` $ sudo bpftool struct_ops dump id 1523612 | jq . > /dev/null parse error: Expected value before ',' at line 19, column 2 ``` After, no error parsing the output: ``` sudo ./bpftool struct_ops dump id 1523612 | jq . > /dev/null ``` Signed-off-by: Manu Bretelle Signed-off-by: Daniel Borkmann Tested-by: Eduard Zingerman Acked-by: Eduard Zingerman Acked-by: Quentin Monnet Link: https://lore.kernel.org/bpf/20231018230133.1593152-3-chantr4@gmail.com

bpftool: Support bpffs mountpoint as pin path for prog loadall

2023-05-17T13:58:18+00:00

Currently, when using prog loadall and the pin path is a bpffs mountpoint, bpffs will be repeatedly mounted to the parent directory of the bpffs mountpoint path. For example, a `bpftool prog loadall test.o /sys/fs/bpf` will trigger this. Signed-off-by: Pengcheng Yang Signed-off-by: Daniel Borkmann Reviewed-by: Quentin Monnet Link: https://lore.kernel.org/bpf/1683342439-3677-1-git-send-email-yangpc@wangsu.com

bpftool: Register struct_ops with a link.

2023-04-21T18:10:10+00:00

You can include an optional path after specifying the object name for the 'struct_ops register' subcommand. Since the commit 226bc6ae6405 ("Merge branch 'Transit between BPF TCP congestion controls.'") has been accepted, it is now possible to create a link for a struct_ops. This can be done by defining a struct_ops in SEC(".struct_ops.link") to make libbpf returns a real link. If we don't pin the links before leaving bpftool, they will disappear. To instruct bpftool to pin the links in a directory with the names of the maps, we need to provide the path of that directory. Signed-off-by: Kui-Feng Lee Reviewed-by: Quentin Monnet Link: https://lore.kernel.org/r/20230420002822.345222-1-kuifeng@meta.com Signed-off-by: Alexei Starovoitov

bpftool: Use bpf_{btf,link,map,prog}_get_info_by_fd()

2023-02-16T23:32:45+00:00

Use the new type-safe wrappers around bpf_obj_get_info_by_fd(). Split the bpf_obj_get_info_by_fd() call in build_btf_type_table() in two, since knowing the type helps with the Memory Sanitizer. Improve map_parse_fd_and_info() type safety by using struct bpf_map_info * instead of void * for info. Signed-off-by: Ilya Leoshkevich Signed-off-by: Andrii Nakryiko Reviewed-by: Quentin Monnet Link: https://lore.kernel.org/bpf/20230214231221.249277-4-iii@linux.ibm.com

bpftool: clean-up usage of libbpf_get_error()

2022-11-21T00:17:46+00:00

bpftool is now totally compliant with libbpf 1.0 mode and is not expected to be compiled with pre-1.0, let's clean-up the usage of libbpf_get_error(). The changes stay aligned with returned errors always negative. - In tools/bpf/bpftool/btf.c This fixes an uninitialized local variable `err` in function do_dump() because it may now be returned without having been set. - This also removes the checks on NULL pointers before calling btf__free() because that function already does the check. Signed-off-by: Sahid Orentino Ferdjaoui Link: https://lore.kernel.org/r/20221120112515.38165-5-sahid.ferdjaoui@industrialdiscipline.com Signed-off-by: Alexei Starovoitov

bpftool: fix error message when function can't register struct_ops

2022-11-21T00:17:46+00:00

It is expected that errno be passed to strerror(). This also cleans this part of code from using libbpf_get_error(). Signed-off-by: Sahid Orentino Ferdjaoui Acked-by: Yonghong Song Suggested-by: Quentin Monnet Reviewed-by: Quentin Monnet Link: https://lore.kernel.org/r/20221120112515.38165-4-sahid.ferdjaoui@industrialdiscipline.com Signed-off-by: Alexei Starovoitov

bpftool: replace return value PTR_ERR(NULL) with 0

2022-11-21T00:17:46+00:00

There is no reasons to keep PTR_ERR() when kern_btf=NULL, let's just return 0. This also cleans this part of code from using libbpf_get_error(). Signed-off-by: Sahid Orentino Ferdjaoui Acked-by: Yonghong Song Suggested-by: Quentin Monnet Link: https://lore.kernel.org/r/20221120112515.38165-3-sahid.ferdjaoui@industrialdiscipline.com Signed-off-by: Alexei Starovoitov

Revert "bpftool: Use libbpf 1.0 API mode instead of RLIMIT_MEMLOCK"

2022-06-14T20:18:06+00:00

This reverts commit a777e18f1bcd32528ff5dfd10a6629b655b05eb8. In commit a777e18f1bcd ("bpftool: Use libbpf 1.0 API mode instead of RLIMIT_MEMLOCK"), we removed the rlimit bump in bpftool, because the kernel has switched to memcg-based memory accounting. Thanks to the LIBBPF_STRICT_AUTO_RLIMIT_MEMLOCK, we attempted to keep compatibility with other systems and ask libbpf to raise the limit for us if necessary. How do we know if memcg-based accounting is supported? There is a probe in libbpf to check this. But this probe currently relies on the availability of a given BPF helper, bpf_ktime_get_coarse_ns(), which landed in the same kernel version as the memory accounting change. This works in the generic case, but it may fail, for example, if the helper function has been backported to an older kernel. This has been observed for Google Cloud's Container-Optimized OS (COS), where the helper is available but rlimit is still in use. The probe succeeds, the rlimit is not raised, and probing features with bpftool, for example, fails. A patch was submitted [0] to update this probe in libbpf, based on what the cilium/ebpf Go library does [1]. It would lower the soft rlimit to 0, attempt to load a BPF object, and reset the rlimit. But it may induce some hard-to-debug flakiness if another process starts, or the current application is killed, while the rlimit is reduced, and the approach was discarded. As a workaround to ensure that the rlimit bump does not depend on the availability of a given helper, we restore the unconditional rlimit bump in bpftool for now. [0] https://lore.kernel.org/bpf/20220609143614.97837-1-quentin@isovalent.com/ [1] https://github.com/cilium/ebpf/blob/v0.9.0/rlimit/rlimit.go#L39 Signed-off-by: Quentin Monnet Signed-off-by: Daniel Borkmann Cc: Yafang Shao Cc: Stanislav Fomichev Link: https://lore.kernel.org/bpf/20220610112648.29695-2-quentin@isovalent.com

bpftool: Use libbpf 1.0 API mode instead of RLIMIT_MEMLOCK

2022-04-11T03:17:16+00:00

We have switched to memcg-based memory accouting and thus the rlimit is not needed any more. LIBBPF_STRICT_AUTO_RLIMIT_MEMLOCK was introduced in libbpf for backward compatibility, so we can use it instead now. libbpf_set_strict_mode always return 0, so we don't need to check whether the return value is 0 or not. Signed-off-by: Yafang Shao Signed-off-by: Andrii Nakryiko Link: https://lore.kernel.org/bpf/20220409125958.92629-4-laoar.shao@gmail.com