diff options
| author | Viktor Malik <vmalik@redhat.com> | 2024-04-30 11:38:06 +0200 |
|---|---|---|
| committer | Andrii Nakryiko <andrii@kernel.org> | 2024-05-01 09:53:47 -0700 |
| commit | 8f8a024272f3e335854515b41638bdf89c6d3146 (patch) | |
| tree | ebd3594f73d8bd495851b1dc43559d04162656c7 | |
| parent | 9a1a2cb5a0e3531d68a2616663ddce49df85dfff (diff) | |
| download | bpf-next-8f8a024272f3e335854515b41638bdf89c6d3146.tar.gz | |
libbpf: support "module: Function" syntax for tracing programs
In some situations, it is useful to explicitly specify a kernel module
to search for a tracing program target (e.g. when a function of the same
name exists in multiple modules or in vmlinux).
This patch enables that by allowing the "module:function" syntax for the
find_kernel_btf_id function. Thanks to this, the syntax can be used both
from a SEC macro (i.e. `SEC(fentry/module:function)`) and via the
bpf_program__set_attach_target API call.
Signed-off-by: Viktor Malik <vmalik@redhat.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/9085a8cb9a552de98e554deb22ff7e977d025440.1714469650.git.vmalik@redhat.com
| -rw-r--r-- | tools/lib/bpf/libbpf.c | 35 |
1 files changed, 26 insertions, 9 deletions
diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c index 7667671187e9d..109b33fb68dc8 100644 --- a/tools/lib/bpf/libbpf.c +++ b/tools/lib/bpf/libbpf.c @@ -9862,16 +9862,28 @@ static int find_kernel_btf_id(struct bpf_object *obj, const char *attach_name, enum bpf_attach_type attach_type, int *btf_obj_fd, int *btf_type_id) { - int ret, i; + int ret, i, mod_len; + const char *fn_name, *mod_name = NULL; - ret = find_attach_btf_id(obj->btf_vmlinux, attach_name, attach_type); - if (ret > 0) { - *btf_obj_fd = 0; /* vmlinux BTF */ - *btf_type_id = ret; - return 0; + fn_name = strchr(attach_name, ':'); + if (fn_name) { + mod_name = attach_name; + mod_len = fn_name - mod_name; + fn_name++; + } + + if (!mod_name || strncmp(mod_name, "vmlinux", mod_len) == 0) { + ret = find_attach_btf_id(obj->btf_vmlinux, + mod_name ? fn_name : attach_name, + attach_type); + if (ret > 0) { + *btf_obj_fd = 0; /* vmlinux BTF */ + *btf_type_id = ret; + return 0; + } + if (ret != -ENOENT) + return ret; } - if (ret != -ENOENT) - return ret; ret = load_module_btfs(obj); if (ret) @@ -9880,7 +9892,12 @@ static int find_kernel_btf_id(struct bpf_object *obj, const char *attach_name, for (i = 0; i < obj->btf_module_cnt; i++) { const struct module_btf *mod = &obj->btf_modules[i]; - ret = find_attach_btf_id(mod->btf, attach_name, attach_type); + if (mod_name && strncmp(mod->name, mod_name, mod_len) != 0) + continue; + + ret = find_attach_btf_id(mod->btf, + mod_name ? fn_name : attach_name, + attach_type); if (ret > 0) { *btf_obj_fd = mod->fd; *btf_type_id = ret; |