From 0c591cacba00a36af797fa3b6c4a4f12d342be86 Mon Sep 17 00:00:00 2001 From: Lucas Werkmeister Date: Sun, 4 Feb 2018 19:30:37 +0100 Subject: daemon: add --log-destination=(stderr|syslog|none) MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit This new option can be used to override the implicit --syslog of --inetd, or to disable all logging. (While --detach also implies --syslog, --log-destination=stderr with --detach is useless since --detach disassociates the process from the original stderr.) --syslog is retained as an alias for --log-destination=syslog. --log-destination always overrides implicit --syslog regardless of option order. This is different than the “last one wins” logic that applies to some implicit options elsewhere in Git, but should hopefully be less confusing. (I also don’t know if *all* implicit options in Git follow “last one wins”.) The combination of --inetd with --log-destination=stderr is useful, for instance, when running `git daemon` as an instanced systemd service (with associated socket unit). In this case, log messages sent via syslog are received by the journal daemon, but run the risk of being processed at a time when the `git daemon` process has already exited (especially if the process was very short-lived, e.g. due to client error), so that the journal daemon can no longer read its cgroup and attach the message to the correct systemd unit (see systemd/systemd#2913 [1]). Logging to stderr instead can solve this problem, because systemd can connect stderr directly to the journal daemon, which then already knows which unit is associated with this stream. [1]: https://github.com/systemd/systemd/issues/2913 Helped-by: Ævar Arnfjörð Bjarmason Helped-by: Junio C Hamano Helped-by: Eric Sunshine Signed-off-by: Lucas Werkmeister Signed-off-by: Junio C Hamano --- daemon.c | 46 +++++++++++++++++++++++++++++++++++++++------- 1 file changed, 39 insertions(+), 7 deletions(-) (limited to 'daemon.c') diff --git a/daemon.c b/daemon.c index e37e343d0a..fb538e3678 100644 --- a/daemon.c +++ b/daemon.c @@ -9,7 +9,12 @@ #define initgroups(x, y) (0) /* nothing */ #endif -static int log_syslog; +static enum log_destination { + LOG_DESTINATION_UNSET = -1, + LOG_DESTINATION_NONE = 0, + LOG_DESTINATION_STDERR = 1, + LOG_DESTINATION_SYSLOG = 2, +} log_destination = LOG_DESTINATION_UNSET; static int verbose; static int reuseaddr; static int informative_errors; @@ -25,6 +30,7 @@ static const char daemon_usage[] = " [--access-hook=]\n" " [--inetd | [--listen=] [--port=]\n" " [--detach] [--user= [--group=]]\n" +" [--log-destination=(stderr|syslog|none)]\n" " [...]"; /* List of acceptable pathname prefixes */ @@ -74,11 +80,14 @@ static const char *get_ip_address(struct hostinfo *hi) static void logreport(int priority, const char *err, va_list params) { - if (log_syslog) { + switch (log_destination) { + case LOG_DESTINATION_SYSLOG: { char buf[1024]; vsnprintf(buf, sizeof(buf), err, params); syslog(priority, "%s", buf); - } else { + break; + } + case LOG_DESTINATION_STDERR: /* * Since stderr is set to buffered mode, the * logging of different processes will not overlap @@ -88,6 +97,11 @@ static void logreport(int priority, const char *err, va_list params) vfprintf(stderr, err, params); fputc('\n', stderr); fflush(stderr); + break; + case LOG_DESTINATION_NONE: + break; + case LOG_DESTINATION_UNSET: + BUG("log destination not initialized correctly"); } } @@ -1289,7 +1303,6 @@ int cmd_main(int argc, const char **argv) } if (!strcmp(arg, "--inetd")) { inetd_mode = 1; - log_syslog = 1; continue; } if (!strcmp(arg, "--verbose")) { @@ -1297,9 +1310,22 @@ int cmd_main(int argc, const char **argv) continue; } if (!strcmp(arg, "--syslog")) { - log_syslog = 1; + log_destination = LOG_DESTINATION_SYSLOG; continue; } + if (skip_prefix(arg, "--log-destination=", &v)) { + if (!strcmp(v, "syslog")) { + log_destination = LOG_DESTINATION_SYSLOG; + continue; + } else if (!strcmp(v, "stderr")) { + log_destination = LOG_DESTINATION_STDERR; + continue; + } else if (!strcmp(v, "none")) { + log_destination = LOG_DESTINATION_NONE; + continue; + } else + die("unknown log destination '%s'", v); + } if (!strcmp(arg, "--export-all")) { export_all_trees = 1; continue; @@ -1356,7 +1382,6 @@ int cmd_main(int argc, const char **argv) } if (!strcmp(arg, "--detach")) { detach = 1; - log_syslog = 1; continue; } if (skip_prefix(arg, "--user=", &v)) { @@ -1402,7 +1427,14 @@ int cmd_main(int argc, const char **argv) usage(daemon_usage); } - if (log_syslog) { + if (log_destination == LOG_DESTINATION_UNSET) { + if (inetd_mode || detach) + log_destination = LOG_DESTINATION_SYSLOG; + else + log_destination = LOG_DESTINATION_STDERR; + } + + if (log_destination == LOG_DESTINATION_SYSLOG) { openlog("git-daemon", LOG_PID, LOG_DAEMON); set_die_routine(daemon_die); } else -- cgit v1.2.3