diff options
| author | Mykyta Yatsenko <yatsenko@meta.com> | 2024-05-24 14:18:40 +0100 |
|---|---|---|
| committer | Andrii Nakryiko <andrii@kernel.org> | 2024-05-28 16:25:06 -0700 |
| commit | eb4e7726279a344c82e3c23be396bcfd0a4d5669 (patch) | |
| tree | 4aca2e5c18389f01ec9919e13ea4f728792b474b | |
| parent | 4b3529edbb8ff069d762c6947e055e10c1748170 (diff) | |
libbpf: Configure log verbosity with env variable
Configure logging verbosity by setting LIBBPF_LOG_LEVEL environment
variable, which is applied only to default logger. Once user set their
custom logging callback, it is up to them to handle filtering.
Signed-off-by: Mykyta Yatsenko <yatsenko@meta.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20240524131840.114289-1-yatsenko@meta.com
| -rw-r--r-- | Documentation/bpf/libbpf/libbpf_overview.rst | 8 | ||||
| -rw-r--r-- | tools/lib/bpf/libbpf.c | 25 | ||||
| -rw-r--r-- | tools/lib/bpf/libbpf.h | 5 |
3 files changed, 36 insertions, 2 deletions
diff --git a/Documentation/bpf/libbpf/libbpf_overview.rst b/Documentation/bpf/libbpf/libbpf_overview.rst index f36a2d4ffea2..f4d22f0c62b0 100644 --- a/Documentation/bpf/libbpf/libbpf_overview.rst +++ b/Documentation/bpf/libbpf/libbpf_overview.rst @@ -219,6 +219,14 @@ compilation and skeleton generation. Using Libbpf-rs will make building user space part of the BPF application easier. Note that the BPF program themselves must still be written in plain C. +libbpf logging +============== + +By default, libbpf logs informational and warning messages to stderr. The +verbosity of these messages can be controlled by setting the environment +variable LIBBPF_LOG_LEVEL to either warn, info, or debug. A custom log +callback can be set using ``libbpf_set_print()``. + Additional Documentation ======================== diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c index 5401f2df463d..d1627a2ca30b 100644 --- a/tools/lib/bpf/libbpf.c +++ b/tools/lib/bpf/libbpf.c @@ -229,7 +229,30 @@ static const char * const prog_type_name[] = { static int __base_pr(enum libbpf_print_level level, const char *format, va_list args) { - if (level == LIBBPF_DEBUG) + const char *env_var = "LIBBPF_LOG_LEVEL"; + static enum libbpf_print_level min_level = LIBBPF_INFO; + static bool initialized; + + if (!initialized) { + char *verbosity; + + initialized = true; + verbosity = getenv(env_var); + if (verbosity) { + if (strcasecmp(verbosity, "warn") == 0) + min_level = LIBBPF_WARN; + else if (strcasecmp(verbosity, "debug") == 0) + min_level = LIBBPF_DEBUG; + else if (strcasecmp(verbosity, "info") == 0) + min_level = LIBBPF_INFO; + else + fprintf(stderr, "libbpf: unrecognized '%s' envvar value: '%s', should be one of 'warn', 'debug', or 'info'.\n", + env_var, verbosity); + } + } + + /* if too verbose, skip logging */ + if (level > min_level) return 0; return vfprintf(stderr, format, args); diff --git a/tools/lib/bpf/libbpf.h b/tools/lib/bpf/libbpf.h index c3f77d9260fe..26e4e35528c5 100644 --- a/tools/lib/bpf/libbpf.h +++ b/tools/lib/bpf/libbpf.h @@ -98,7 +98,10 @@ typedef int (*libbpf_print_fn_t)(enum libbpf_print_level level, /** * @brief **libbpf_set_print()** sets user-provided log callback function to - * be used for libbpf warnings and informational messages. + * be used for libbpf warnings and informational messages. If the user callback + * is not set, messages are logged to stderr by default. The verbosity of these + * messages can be controlled by setting the environment variable + * LIBBPF_LOG_LEVEL to either warn, info, or debug. * @param fn The log print function. If NULL, libbpf won't print anything. * @return Pointer to old print function. * |