diff options
author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-05-04 14:18:53 +0000 |
---|---|---|
committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-05-04 14:18:53 +0000 |
commit | a0e0018c9a7ef5ce7f6d2c3ae16aecbbd16a8f67 (patch) | |
tree | 8feaf1a1932871b139b3b30be4c09c66489918be /lib/bpf_glue.c | |
parent | Initial commit. (diff) | |
download | iproute2-upstream/6.1.0.tar.xz iproute2-upstream/6.1.0.zip |
Adding upstream version 6.1.0.upstream/6.1.0upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to '')
-rw-r--r-- | lib/bpf_glue.c | 91 |
1 files changed, 91 insertions, 0 deletions
diff --git a/lib/bpf_glue.c b/lib/bpf_glue.c new file mode 100644 index 0000000..88a2475 --- /dev/null +++ b/lib/bpf_glue.c @@ -0,0 +1,91 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * bpf_glue.c: BPF code to call both legacy and libbpf code + * Authors: Hangbin Liu <haliu@redhat.com> + * + */ +#include <sys/syscall.h> +#include <limits.h> +#include <unistd.h> +#include <errno.h> + +#include "bpf_util.h" +#ifdef HAVE_LIBBPF +#include <bpf/bpf.h> +#endif + +int bpf(int cmd, union bpf_attr *attr, unsigned int size) +{ +#ifdef __NR_bpf + return syscall(__NR_bpf, cmd, attr, size); +#else + fprintf(stderr, "No bpf syscall, kernel headers too old?\n"); + errno = ENOSYS; + return -1; +#endif +} + +int bpf_program_attach(int prog_fd, int target_fd, enum bpf_attach_type type) +{ +#ifdef HAVE_LIBBPF + return bpf_prog_attach(prog_fd, target_fd, type, 0); +#else + return bpf_prog_attach_fd(prog_fd, target_fd, type); +#endif +} + +#ifdef HAVE_LIBBPF +static const char *_libbpf_compile_version = LIBBPF_VERSION; +static char _libbpf_version[10] = {}; + +const char *get_libbpf_version(void) +{ + /* Start by copying compile-time version into buffer so we have a + * fallback value in case we are dynamically linked, or can't find a + * version in /proc/self/maps below. + */ + strncpy(_libbpf_version, _libbpf_compile_version, + sizeof(_libbpf_version)-1); +#ifdef LIBBPF_DYNAMIC + char buf[PATH_MAX], *s; + bool found = false; + FILE *fp; + + /* When dynamically linking against libbpf, we can't be sure that the + * version we discovered at compile time is actually the one we are + * using at runtime. This can lead to hard-to-debug errors, so we try to + * discover the correct version at runtime. + * + * The simple solution to this would be if libbpf itself exported a + * version in its API. But since it doesn't, we work around this by + * parsing the mappings of the binary at runtime, looking for the full + * filename of libbpf.so and using that. + */ + fp = fopen("/proc/self/maps", "r"); + if (fp == NULL) + goto out; + + while (fgets(buf, sizeof(buf), fp) != NULL) { + if ((s = strstr(buf, "libbpf.so.")) != NULL) { + strncpy(_libbpf_version, s+10, sizeof(_libbpf_version)-1); + strtok(_libbpf_version, "\n"); + found = true; + break; + } + } + + fclose(fp); +out: + if (!found) + fprintf(stderr, "Couldn't find runtime libbpf version - falling back to compile-time value!\n"); +#endif /* LIBBPF_DYNAMIC */ + + _libbpf_version[sizeof(_libbpf_version)-1] = '\0'; + return _libbpf_version; +} +#else +const char *get_libbpf_version(void) +{ + return NULL; +} +#endif /* HAVE_LIBBPF */ |