3 files changed, 64 insertions, 0 deletions

diff --git a/tools/include/nolibc/crt.h b/tools/include/nolibc/crt.h
index d9262998dae9..5bb492555f13 100644
--- a/tools/include/nolibc/crt.h
+++ b/tools/include/nolibc/crt.h
@@ -17,6 +17,7 @@ const unsigned long *_auxv __attribute__((weak));
 void _start(void);
 static void __stack_chk_init(void);
 static void exit(int);
+static char *strrchr(const char *s, int c);
 
 extern void (*const __preinit_array_start[])(int, char **, char**) __attribute__((weak));
 extern void (*const __preinit_array_end[])(int, char **, char**) __attribute__((weak));
@@ -27,6 +28,24 @@ extern void (*const __init_array_end[])(int, char **, char**) __attribute__((wea
 extern void (*const __fini_array_start[])(void) __attribute__((weak));
 extern void (*const __fini_array_end[])(void) __attribute__((weak));
 
+#ifndef NOLIBC_IGNORE_ERRNO
+extern char *program_invocation_name __attribute__((weak));
+extern char *program_invocation_short_name __attribute__((weak));
+
+static __inline__
+char *__nolibc_program_invocation_short_name(char *long_name)
+{
+
+	char *short_name;
+
+	short_name = strrchr(long_name, '/');
+	if (!short_name || !short_name[0])
+		return long_name;
+
+	return short_name + 1;
+}
+#endif /* NOLIBC_IGNORE_ERRNO */
+
 void _start_c(long *sp);
 __attribute__((weak,used))
 #if __nolibc_has_feature(undefined_behavior_sanitizer)
@@ -76,6 +95,13 @@ void _start_c(long *sp)
 		;
 	_auxv = auxv;
 
+#ifndef NOLIBC_IGNORE_ERRNO
+	if (argc > 0 && argv[0]) {
+		program_invocation_name = argv[0];
+		program_invocation_short_name = __nolibc_program_invocation_short_name(argv[0]);
+	}
+#endif /* NOLIBC_IGNORE_ERRNO */
+
 	for (ctor_func = __preinit_array_start; ctor_func < __preinit_array_end; ctor_func++)
 		(*ctor_func)(argc, argv, envp);
 	for (ctor_func = __init_array_start; ctor_func < __init_array_end; ctor_func++)
diff --git a/tools/include/nolibc/errno.h b/tools/include/nolibc/errno.h
index 08a33c40ec0c..bab83692ea1c 100644
--- a/tools/include/nolibc/errno.h
+++ b/tools/include/nolibc/errno.h
@@ -15,8 +15,12 @@
 #ifndef NOLIBC_IGNORE_ERRNO
 #define SET_ERRNO(v) do { errno = (v); } while (0)
 int errno __attribute__((weak));
+char *program_invocation_name __attribute__((weak)) = "";
+char *program_invocation_short_name __attribute__((weak)) = "";
 #else
 #define SET_ERRNO(v) do { } while (0)
+#define program_invocation_name ""
+#define program_invocation_short_name ""
 #endif
 
 
diff --git a/tools/testing/selftests/nolibc/nolibc-test.c b/tools/testing/selftests/nolibc/nolibc-test.c
index 0ca695acbc44..1efd10152e83 100644
--- a/tools/testing/selftests/nolibc/nolibc-test.c
+++ b/tools/testing/selftests/nolibc/nolibc-test.c
@@ -42,6 +42,7 @@
 #include <unistd.h>
 #include <limits.h>
 #include <ctype.h>
+#include <stdbool.h>
 
 #pragma GCC diagnostic ignored "-Wmissing-prototypes"
 
@@ -710,6 +711,37 @@ static void constructor2(int argc, char **argv, char **envp)
 		constructor_test_value |= 1 << 1;
 }
 
+int test_program_invocation_name(void)
+{
+	char buf[100];
+	char *dirsep;
+	ssize_t r;
+	int fd;
+
+	fd = open("/proc/self/cmdline", O_RDONLY);
+	if (fd == -1)
+		return 1;
+
+	r = read(fd, buf, sizeof(buf));
+	close(fd);
+	if (r < 1 || r == sizeof(buf))
+		return 1;
+
+	buf[r - 1] = '\0';
+
+	if (strcmp(program_invocation_name, buf) != 0)
+		return 1;
+
+	dirsep = strrchr(buf, '/');
+	if (!dirsep || dirsep[1] == '\0')
+		return 1;
+
+	if (strcmp(program_invocation_short_name, dirsep + 1) != 0)
+		return 1;
+
+	return 0;
+}
+
 int run_startup(int min, int max)
 {
 	int test;
@@ -724,6 +756,7 @@ int run_startup(int min, int max)
 #ifdef NOLIBC
 	test_auxv = _auxv;
 #endif
+	bool proc = access("/proc", R_OK) == 0;
 
 	for (test = min; test >= 0 && test <= max; test++) {
 		int llen = 0; /* line length */
@@ -749,6 +782,7 @@ int run_startup(int min, int max)
 		CASE_TEST(constructor);      EXPECT_EQ(is_nolibc, constructor_test_value, 0x3); break;
 		CASE_TEST(linkage_errno);    EXPECT_PTREQ(1, linkage_test_errno_addr(), &errno); break;
 		CASE_TEST(linkage_constr);   EXPECT_EQ(1, linkage_test_constructor_test_value, 0x3); break;
+		CASE_TEST(prog_name);        EXPECT_ZR(proc, test_program_invocation_name()); break;
 		case __LINE__:
 			return ret; /* must be last */
 		/* note: do not set any defaults so as to permit holes above */