shared/bpf: install log callback and suppress most messages from libbpf

$ build/test-socket-bind
...
libbpf: load bpf program failed: Operation not permitted
libbpf: failed to load program 'sd_bind4'
libbpf: failed to load object 'socket_bind_bpf'
libbpf: failed to load BPF skeleton 'socket_bind_bpf': -1
Failed to load BPF object: Operation not permitted

Now all lines with "libbpf:" are at debug level and will be hidden by
default.

Partially fixes https://bugzilla.redhat.com/show_bug.cgi?id=2084955#c14
(i.e. the error that was exposed when the initial error was fixed.)
This commit is contained in:
Zbigniew Jędrzejewski-Szmek 2022-06-02 00:27:52 +02:00
parent 386b8026e5
commit 44005a5778
2 changed files with 28 additions and 3 deletions

View file

@ -9,7 +9,6 @@ static void *bpf_dl = NULL;
struct bpf_link* (*sym_bpf_program__attach_cgroup)(struct bpf_program *, int);
struct bpf_link* (*sym_bpf_program__attach_lsm)(struct bpf_program *);
long (*sym_libbpf_get_error)(const void *);
int (*sym_bpf_link__fd)(const struct bpf_link *);
int (*sym_bpf_link__destroy)(struct bpf_link *);
int (*sym_bpf_map__fd)(const struct bpf_map *);
@ -26,9 +25,27 @@ void (*sym_bpf_object__detach_skeleton)(struct bpf_object_skeleton *);
void (*sym_bpf_object__destroy_skeleton)(struct bpf_object_skeleton *);
bool (*sym_bpf_probe_prog_type)(enum bpf_prog_type, __u32);
const char* (*sym_bpf_program__name)(const struct bpf_program *);
libbpf_print_fn_t (*sym_libbpf_set_print)(libbpf_print_fn_t);
long (*sym_libbpf_get_error)(const void *);
_printf_(2,0)
static int bpf_print_func(enum libbpf_print_level level, const char *fmt, va_list ap) {
#if !LOG_TRACE
/* libbpf logs a lot of details at its debug level, which we don't need to see. */
if (level == LIBBPF_DEBUG)
return 0;
#endif
/* All other levels are downgraded to LOG_DEBUG */
/* errno is used here, on the assumption that if the log message uses %m, errno will be set to
* something useful. Otherwise, it shouldn't matter, we may pass 0 or some bogus value. */
return log_internalv(LOG_DEBUG, errno, NULL, 0, NULL, fmt, ap);
}
int dlopen_bpf(void) {
return dlopen_many_sym_or_warn(
int r;
r = dlopen_many_sym_or_warn(
&bpf_dl, "libbpf.so.0", LOG_DEBUG,
DLSYM_ARG(bpf_link__destroy),
DLSYM_ARG(bpf_link__fd),
@ -48,7 +65,14 @@ int dlopen_bpf(void) {
DLSYM_ARG(bpf_program__attach_cgroup),
DLSYM_ARG(bpf_program__attach_lsm),
DLSYM_ARG(bpf_program__name),
DLSYM_ARG(libbpf_set_print),
DLSYM_ARG(libbpf_get_error));
if (r < 0)
return r;
/* We set the print helper unconditionally. Otherwise libbpf will emit not useful log messages. */
(void) sym_libbpf_set_print(bpf_print_func);
return r;
}
#else

View file

@ -8,7 +8,6 @@
extern struct bpf_link* (*sym_bpf_program__attach_cgroup)(struct bpf_program *, int);
extern struct bpf_link* (*sym_bpf_program__attach_lsm)(struct bpf_program *);
extern long (*sym_libbpf_get_error)(const void *);
extern int (*sym_bpf_link__fd)(const struct bpf_link *);
extern int (*sym_bpf_link__destroy)(struct bpf_link *);
extern int (*sym_bpf_map__fd)(const struct bpf_map *);
@ -27,6 +26,8 @@ extern void (*sym_bpf_object__detach_skeleton)(struct bpf_object_skeleton *);
extern void (*sym_bpf_object__destroy_skeleton)(struct bpf_object_skeleton *);
extern bool (*sym_bpf_probe_prog_type)(enum bpf_prog_type, __u32);
extern const char* (*sym_bpf_program__name)(const struct bpf_program *);
extern libbpf_print_fn_t (*sym_libbpf_set_print)(libbpf_print_fn_t);
extern long (*sym_libbpf_get_error)(const void *);
#endif