libbpf-tools: Add verbose option to mountsnoop

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

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

diff --git a/libbpf-tools/mountsnoop.c b/libbpf-tools/mountsnoop.c
index 6bf7ee5..ac2acc4 100644 (file)
--- a/libbpf-tools/mountsnoop.c
+++ b/libbpf-tools/mountsnoop.c
@@ -38,6 +38,7 @@ static volatile sig_atomic_t exiting = 0;
 static pid_t target_pid = 0;
 static bool emit_timestamp = false;
 static bool output_vertically = false;
+static bool verbose = false;
 static const char *flag_names[] = {
        [0] = "MS_RDONLY",
        [1] = "MS_NOSUID",
@@ -91,6 +92,7 @@ static const struct argp_option opts[] = {
        { "pid", 'p', "PID", 0, "Process ID to trace" },
        { "timestamp", 't', NULL, 0, "Include timestamp on output" },
        { "detailed", 'd', NULL, 0, "Output result in detail mode" },
+       { "verbose", 'v', NULL, 0, "Verbose debug output" },
        { NULL, 'h', NULL, OPTION_HIDDEN, "Show the full help" },
        {},
 };
@@ -115,6 +117,9 @@ static error_t parse_arg(int key, char *arg, struct argp_state *state)
        case 'd':
                output_vertically = true;
                break;
+       case 'v':
+               verbose = true;
+               break;
        case 'h':
                argp_state_help(state, stderr, ARGP_HELP_STD_HELP);
                break;
@@ -124,6 +129,13 @@ 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;
@@ -246,6 +258,7 @@ int main(int argc, char **argv)
                return err;
 
        libbpf_set_strict_mode(LIBBPF_STRICT_ALL);
+       libbpf_set_print(libbpf_print_fn);
 
        obj = mountsnoop_bpf__open();
        if (!obj) {