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BTF-playground: Extract BTF name while walking all IDs

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Signed-off-by: Jesper Dangaard Brouer <netoptimizer@brouer.com>
This commit is contained in:
Jesper Dangaard Brouer
2022-08-31 11:42:40 +02:00
parent 55fcfcce87
commit e00b6a66e6
1 changed files with 39 additions and 2 deletions
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41
BTF-playground/btf_module_ids.c
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@@ -28,6 +28,16 @@ int print_all_levels(enum libbpf_print_level level,
#define pr_err(fmt, ...) \
fprintf(stderr, "%s:%d - " fmt, __FILE__, __LINE__, ##__VA_ARGS__)
static inline __u64 ptr_to_u64(const void *ptr)
{
return (__u64) (unsigned long) ptr;
}
static inline const void *u64_to_ptr(__u64 val)
{
return (const void *)(unsigned long)val;
}
int __btf_obj_id_via_fd(int fd)
{
struct bpf_btf_info info;
@@ -46,6 +56,30 @@ int __btf_obj_id_via_fd(int fd)
return info.id;
}
char * __btf_obj_name_via_fd(int fd)
{
struct bpf_btf_info info;
__u32 len = sizeof(info);
char name[128];
int err;
memset(&info, 0, sizeof(info));
memset(name, 0, sizeof(name));
info.name_len = sizeof(name);
info.name = ptr_to_u64(name);
err = bpf_obj_get_info_by_fd(fd, &info, &len); /* Privileged op */
if (err) {
pr_err("ERR(%d): Can't get BTF object info on FD(%d): %s\n",
errno, fd, strerror(errno));
return 0;
}
/* Caller must call free() */
return strndup(name, sizeof(name));
}
struct btf *open_vmlinux_btf(void)
{
struct btf* btf_obj;
@@ -64,6 +98,7 @@ struct btf *open_vmlinux_btf(void)
int walk_all_ids(void)
{
__u32 lookup_id, id = 0;
char *name;
int err;
int fd;
@@ -93,8 +128,10 @@ int walk_all_ids(void)
}
lookup_id = __btf_obj_id_via_fd(fd);
printf("Walk id:%d lookup_id:%d (FD:%d)\n",
id, lookup_id, fd);
name = __btf_obj_name_via_fd(fd);
printf("Walk id:%d lookup_id:%d name:%s\t\t(FD:%d)\n",
id, lookup_id, name, fd);
free(name);
close(fd);
}