libbpf-tools: Add verbose option to statsnoop

Support verbose mode and set custom libbpf print callback
in statsnoop.

Signed-off-by: Hengqi Chen <chenhengqi@outlook.com>

diff --git a/libbpf-tools/statsnoop.c b/libbpf-tools/statsnoop.c
index 2c0b35de435c1615a370129530cce7864920ab8b..3f8f5c58c84fe394adf12c30db2dd850593211d0 100644 (file)
--- a/libbpf-tools/statsnoop.c
+++ b/libbpf-tools/statsnoop.c
@@ -23,6 +23,7 @@ static volatile sig_atomic_t exiting = 0;
 static pid_t target_pid = 0;
 static bool trace_failed_only = false;
 static bool emit_timestamp = false;
+static bool verbose = false;
 
 const char *argp_program_version = "statsnoop 0.1";
 const char *argp_program_bug_address =
@@ -39,10 +40,11 @@ const char argp_program_doc[] =
 "    statsnoop -p 1216     # only trace PID 1216\n";
 
 static const struct argp_option opts[] = {
-       {"pid", 'p', "PID", 0, "Process ID to trace"},
-       {"failed", 'x', NULL, 0, "Only show failed stats"},
-       {"timestamp", 't', NULL, 0, "Include timestamp on output"},
-       {NULL, 'h', NULL, OPTION_HIDDEN, "Show the full help"},
+       { "pid", 'p', "PID", 0, "Process ID to trace" },
+       { "failed", 'x', NULL, 0, "Only show failed stats" },
+       { "timestamp", 't', NULL, 0, "Include timestamp on output" },
+       { "verbose", 'v', NULL, 0, "Verbose debug output" },
+       { NULL, 'h', NULL, OPTION_HIDDEN, "Show the full help" },
        {},
 };
 
@@ -66,6 +68,9 @@ static error_t parse_arg(int key, char *arg, struct argp_state *state)
        case 't':
                emit_timestamp = true;
                break;
+       case 'v':
+               verbose = true;
+               break;
        case 'h':
                argp_state_help(state, stderr, ARGP_HELP_STD_HELP);
                break;
@@ -75,6 +80,13 @@ static error_t parse_arg(int key, char *arg, struct argp_state *state)
        return 0;
 }
 
+static int libbpf_print_fn(enum libbpf_print_level level, const char *format, va_list args)
+{
+       if (level == LIBBPF_DEBUG && !verbose)
+               return 0;
+       return vfprintf(stderr, format, args);
+}
+
 static void sig_int(int signo)
 {
        exiting = 1;
@@ -124,6 +136,7 @@ int main(int argc, char **argv)
                return err;
 
        libbpf_set_strict_mode(LIBBPF_STRICT_ALL);
+       libbpf_set_print(libbpf_print_fn);
 
        obj = statsnoop_bpf__open();
        if (!obj) {