flock: add --verbose option

Jenkins script jobs using flock are a great example of a situation in
which one may want an automation to be verbose, so that when unexpected
events happen there is more hints in logs.

Reviewed-by: Benno Schulenberg <bensberg@justemail.net>
Signed-off-by: Sami Kerola <kerolasa@iki.fi>

diff --git a/sys-utils/Makemodule.am b/sys-utils/Makemodule.am
index 8e6108d07148e38ff6c9e9e9cb8bc8f468b37331..b6b0f91acf2a0b4e7e9b0316dd6c04c214b96f29 100644 (file)
--- a/sys-utils/Makemodule.am
+++ b/sys-utils/Makemodule.am
@@ -1,8 +1,8 @@
 if BUILD_FLOCK
 usrbin_exec_PROGRAMS += flock
 dist_man_MANS += sys-utils/flock.1
-flock_SOURCES = sys-utils/flock.c
-flock_LDADD = $(LDADD) libcommon.la
+flock_SOURCES = sys-utils/flock.c lib/monotonic.c
+flock_LDADD = $(LDADD) libcommon.la $(CLOCKGETTIME_LIBS)
 endif
 
 if BUILD_IPCMK

diff --git a/sys-utils/flock.1 b/sys-utils/flock.1
index cdc294b24de5732d103abb9bc90aafd75d099e38..8e9d5c29a2890405d8b9c84eccedee61c5a2598b 100644 (file)
--- a/sys-utils/flock.1
+++ b/sys-utils/flock.1
@@ -107,6 +107,10 @@ option for the exit code used. The zero number of
 .IR seconds
 is interpreted as \fB\-\-nonblock\fR.
 .TP
+.B \-\-verbose
+Report how long it took to acquire the lock, or why the lock could not be
+obtained.
+.TP
 .BR \-V , " \-\-version"
 Display version information and exit.
 .TP

diff --git a/sys-utils/flock.c b/sys-utils/flock.c
index 38281551b184e1788acf8724978264b3598aaa26..707c5992bb25ed478ff62e65363a9f05009da53f 100644 (file)
--- a/sys-utils/flock.c
+++ b/sys-utils/flock.c
@@ -44,6 +44,7 @@
 #include "strutils.h"
 #include "closestream.h"
 #include "timer.h"
+#include "monotonic.h"
 
 static void __attribute__((__noreturn__)) usage(int ex)
 {
@@ -66,6 +67,7 @@ static void __attribute__((__noreturn__)) usage(int ex)
        fputs(_(  " -E, --conflict-exit-code <number>  exit code after conflict or timeout\n"), stderr);
        fputs(_(  " -o, --close              close file descriptor before running command\n"), stderr);
        fputs(_(  " -c, --command <command>  run a single command string through the shell\n"), stderr);
+       fputs(_(  "     --verbose            increase verbosity\n"), stderr);
        fprintf(stderr, USAGE_SEPARATOR);
        fprintf(stderr, USAGE_HELP);
        fprintf(stderr, USAGE_VERSION);
@@ -120,6 +122,8 @@ int main(int argc, char *argv[])
        int opt, ix;
        int do_close = 0;
        int status;
+       int verbose = 0;
+       struct timeval time_start, time_done;
        /*
         * The default exit code for lock conflict or timeout
         * is specified in man flock.1
@@ -128,7 +132,9 @@ int main(int argc, char *argv[])
        char **cmd_argv = NULL, *sh_c_argv[4];
        const char *filename = NULL;
        struct sigaction old_sa;
-
+       enum {
+               OPT_VERBOSE = CHAR_MAX + 1
+       };
        static const struct option long_options[] = {
                {"shared", no_argument, NULL, 's'},
                {"exclusive", no_argument, NULL, 'x'},
@@ -139,6 +145,7 @@ int main(int argc, char *argv[])
                {"wait", required_argument, NULL, 'w'},
                {"conflict-exit-code", required_argument, NULL, 'E'},
                {"close", no_argument, NULL, 'o'},
+               {"verbose", no_argument, NULL, OPT_VERBOSE},
                {"help", no_argument, NULL, 'h'},
                {"version", no_argument, NULL, 'V'},
                {NULL, 0, NULL, 0}
@@ -184,6 +191,9 @@ int main(int argc, char *argv[])
                        conflict_exit_code = strtos32_or_err(optarg,
                                _("invalid exit code"));
                        break;
+               case OPT_VERBOSE:
+                       verbose = 1;
+                       break;
                case 'V':
                        printf(UTIL_LINUX_VERSION);
                        exit(EX_OK);
@@ -239,16 +249,23 @@ int main(int argc, char *argv[])
                        setup_timer(&timeout, &old_timer, &old_sa, timeout_handler);
        }
 
+       if (verbose)
+               gettime_monotonic(&time_start);
        while (flock(fd, type | block)) {
                switch (errno) {
                case EWOULDBLOCK:
                        /* -n option set and failed to lock. */
+                       if (verbose)
+                               warnx(_("failed to get lock"));
                        exit(conflict_exit_code);
                case EINTR:
                        /* Signal received */
-                       if (timeout_expired)
+                       if (timeout_expired) {
                                /* -w option set and failed to lock. */
+                               if (verbose)
+                                       warnx(_("timeout while waiting to get lock"));
                                exit(conflict_exit_code);
+                       }
                        /* otherwise try again */
                        continue;
                case EIO:
@@ -282,13 +299,23 @@ int main(int argc, char *argv[])
 
        if (have_timeout)
                cancel_timer(&old_timer, &old_sa);
+       if (verbose) {
+               struct timeval delta;
 
+               gettime_monotonic(&time_done);
+               timersub(&time_done, &time_start, &delta);
+               printf(_("%s: getting lock took %ld.%06ld seconds\n"),
+                      program_invocation_short_name, delta.tv_sec,
+                      delta.tv_usec);
+       }
        status = EX_OK;
 
        if (cmd_argv) {
                pid_t w, f;
                /* Clear any inherited settings */
                signal(SIGCHLD, SIG_DFL);
+               if (verbose)
+                       printf(_("%s: executing %s\n"), program_invocation_short_name, cmd_argv[2]);
                f = fork();
 
                if (f < 0) {