[PATCH bpf-next] libbpf: configure log verbosity with env variable

[Mykyta Yatsenko mykyta.yatsenko5@gmail.com]

From: Mykyta Yatsenko <yatsenko@meta.com>

Configure logging verbosity by setting LIBBPF_LOG environment
variable. Only applying to default logger. Once user set their custom
logging callback, it is up to them to filter.

Signed-off-by: Mykyta Yatsenko <yatsenko@meta.com>
---
 tools/lib/bpf/libbpf.c | 18 +++++++++++++++++-
 1 file changed, 17 insertions(+), 1 deletion(-)

diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index 5401f2df463d..8805607073da 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -229,7 +229,23 @@ 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)
+	static enum libbpf_print_level env_level = LIBBPF_INFO;
+	static bool initialized;
+
+	if (!initialized) {
+		char *verbosity;
+
+		initialized = true;
+		verbosity = getenv("LIBBPF_LOG");
+		if (verbosity) {
+			if (strcmp(verbosity, "warn") == 0)
+				env_level = LIBBPF_WARN;
+			else if (strcmp(verbosity, "debug") == 0)
+				env_level = LIBBPF_DEBUG;
+		}
+	}
+
+	if (env_level < level)
 		return 0;
 
 	return vfprintf(stderr, format, args);
-- 
2.45.0