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r341692 changed cap_syslog(3) to preserve the stdio descriptors inherited

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from its parent so that LOG_PERROR would work.  However, this caused
dhclient(8)'s stdio streams to remain open across daemonization, breaking
the ability to capture its foreground output as done in netconfig_ipv4.

Fix this by reverting r341692 and instead passing the parent's stderr
descriptor as an argument to cap_openlog() only when LOG_PERROR is specified
in logopt.

PR:	234514
Suggested by:	markj
Reported by:	Shawn Webb
Reviewed by:	markj, oshogbo
MFC after:	2 weeks
Differential Revision:	https://reviews.freebsd.org/D18989
This commit is contained in:
Jason A. Harmening 2019-02-06 04:36:28 +00:00
parent d70ad055e0
commit f048354550
1 changed files with 26 additions and 3 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

29
lib/libcasper/services/cap_syslog/cap_syslog.c
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@ -88,6 +88,9 @@ cap_openlog(cap_channel_t *chan, const char *ident, int logopt, int facility)
}
nvlist_add_number(nvl, "logopt", logopt);
nvlist_add_number(nvl, "facility", facility);
if (logopt & LOG_PERROR) {
nvlist_add_descriptor(nvl, "stderr", STDERR_FILENO);
}
nvl = cap_xfer_nvlist(chan, nvl);
if (nvl == NULL) {
return;
@ -131,6 +134,7 @@ cap_setlogmask(cap_channel_t *chan, int maskpri)
*/
static char *LogTag;
static int prev_stderr = -1;
static void
slog_vsyslog(const nvlist_t *limits __unused, const nvlist_t *nvlin,
@ -146,6 +150,8 @@ slog_openlog(const nvlist_t *limits __unused, const nvlist_t *nvlin,
nvlist_t *nvlout __unused)
{
const char *ident;
uint64_t logopt;
int stderr_fd;
ident = dnvlist_get_string(nvlin, "ident", NULL);
if (ident != NULL) {
@ -153,8 +159,19 @@ slog_openlog(const nvlist_t *limits __unused, const nvlist_t *nvlin,
LogTag = strdup(ident);
}
openlog(LogTag, nvlist_get_number(nvlin, "logopt"),
nvlist_get_number(nvlin, "facility"));
logopt = nvlist_get_number(nvlin, "logopt");
if (logopt & LOG_PERROR) {
stderr_fd = dnvlist_get_descriptor(nvlin, "stderr", -1);
if (prev_stderr == -1)
prev_stderr = dup(STDERR_FILENO);
if (prev_stderr != -1)
(void)dup2(stderr_fd, STDERR_FILENO);
} else if (prev_stderr != -1) {
(void)dup2(prev_stderr, STDERR_FILENO);
close(prev_stderr);
prev_stderr = -1;
}
openlog(LogTag, logopt, nvlist_get_number(nvlin, "facility"));
}
static void
@ -166,6 +183,12 @@ slog_closelog(const nvlist_t *limits __unused, const nvlist_t *nvlin __unused,
free(LogTag);
LogTag = NULL;
if (prev_stderr != -1) {
(void)dup2(prev_stderr, STDERR_FILENO);
close(prev_stderr);
prev_stderr = -1;
}
}
static void
@ -198,4 +221,4 @@ syslog_command(const char *cmd, const nvlist_t *limits, nvlist_t *nvlin,
return (0);
}
CREATE_SERVICE("system.syslog", NULL, syslog_command, CASPER_SERVICE_STDIO);
CREATE_SERVICE("system.syslog", NULL, syslog_command, 0);