git: 7fa95d69f108 - stable/12 - dd a new option (-H) to daemon(8) to catch SIGHUP and re-open output_file file when received.
Mark Johnston
markj at FreeBSD.org
Wed Jul 28 12:40:50 UTC 2021
The branch stable/12 has been updated by markj:
URL: https://cgit.FreeBSD.org/src/commit/?id=7fa95d69f10827d0b02607682a2c4a1513d658e5
commit 7fa95d69f10827d0b02607682a2c4a1513d658e5
Author: Maxim Sobolev <sobomax at FreeBSD.org>
AuthorDate: 2020-09-24 02:44:58 +0000
Commit: Mark Johnston <markj at FreeBSD.org>
CommitDate: 2021-07-28 12:38:38 +0000
dd a new option (-H) to daemon(8) to catch SIGHUP and re-open output_file file when
received.
The default system log rotation mechanism (newsyslog(8)) requires ability to send
signal to a daemon in order to properly complete rotation of the logs in an "atomic"
manner without having to making a copy and truncating original file. Unfortunately
our built-in mechanism to convert "dumb" programs into daemons has no way to handle
this rotation properly. This change adds this ability, to be enabled by supplying -H
option in addition to the -o option.
PR: 255198
Reviewed by: markj, rpokala (manpages)
(cherry picked from commit 4cd407ec933b81d9d0f733532d29426416cccc06)
---
usr.sbin/daemon/daemon.8 | 18 ++++++++++++--
usr.sbin/daemon/daemon.c | 63 ++++++++++++++++++++++++++++++++++++++++++------
2 files changed, 71 insertions(+), 10 deletions(-)
diff --git a/usr.sbin/daemon/daemon.8 b/usr.sbin/daemon/daemon.8
index bd853652c03f..665108df6afc 100644
--- a/usr.sbin/daemon/daemon.8
+++ b/usr.sbin/daemon/daemon.8
@@ -26,7 +26,7 @@
.\"
.\" $FreeBSD$
.\"
-.Dd October 2, 2019
+.Dd September 22, 2020
.Dt DAEMON 8
.Os
.Sh NAME
@@ -34,7 +34,7 @@
.Nd run detached from the controlling terminal
.Sh SYNOPSIS
.Nm
-.Op Fl cfrS
+.Op Fl cfHrS
.Op Fl p Ar child_pidfile
.Op Fl P Ar supervisor_pidfile
.Op Fl t Ar title
@@ -68,6 +68,14 @@ or syslog output, the standard file descriptors are first redirected to
.Pa /dev/null ,
then stdout and/or stderr is redirected to a file or to syslog as
specified by the other options.
+.It Fl H
+Close
+.Pa output_file
+and re-open it when signal SIGHUP is received, for interoperability with
+.Xr newsyslog 1
+and similar log rotation / archival mechanisms. If
+.Fa o
+is not specified, this flag is ignored.
.It Fl S
Enable syslog output.
This is implicitly applied if other syslog parameters are provided.
@@ -77,6 +85,12 @@ tag, respectively.
Append output from the daemonized process to
.Pa output_file .
If the file does not exist, it is created with permissions 0600.
+When this option is used together with options
+.Fl c and
+.Fl H
+the absolute path needs to be provided to ensure
+.Nm
+can re-open the file after a SIGHUP.
.It Fl m Ar output_mask
Redirect output from the child process stdout (1), stderr (2), or both (3).
This value specifies what is sent to syslog and the log file.
diff --git a/usr.sbin/daemon/daemon.c b/usr.sbin/daemon/daemon.c
index 7a245421e4df..d8a26132223b 100644
--- a/usr.sbin/daemon/daemon.c
+++ b/usr.sbin/daemon/daemon.c
@@ -61,11 +61,15 @@ struct log_params {
int logpri;
int noclose;
int outfd;
+ const char *outfn;
};
static void restrict_process(const char *);
static void handle_term(int);
static void handle_chld(int);
+static void handle_hup(int);
+static int open_log(const char *);
+static void reopen_log(struct log_params *);
static int listen_child(int, struct log_params *);
static int get_log_mapping(const char *, const CODE *);
static void open_pid_files(const char *, const char *, struct pidfh **,
@@ -74,7 +78,8 @@ static void do_output(const unsigned char *, size_t, struct log_params *);
static void daemon_sleep(time_t, long);
static void usage(void);
-static volatile sig_atomic_t terminate = 0, child_gone = 0, pid = 0;
+static volatile sig_atomic_t terminate = 0, child_gone = 0, pid = 0,
+ do_log_reopen = 0;
int
main(int argc, char *argv[])
@@ -84,7 +89,7 @@ main(int argc, char *argv[])
sigset_t mask_susp, mask_orig, mask_read, mask_term;
struct log_params logpar;
int pfd[2] = { -1, -1 }, outfd = -1;
- int stdmask, logpri, logfac;
+ int stdmask, logpri, logfac, log_reopen;
struct pidfh *ppfh, *pfh;
char *p;
@@ -97,9 +102,10 @@ main(int argc, char *argv[])
logtag = "daemon";
restart = 0;
dosyslog = 0;
+ log_reopen = 0;
outfn = NULL;
title = NULL;
- while ((ch = getopt(argc, argv, "cfSp:P:ru:o:s:l:t:l:m:R:T:")) != -1) {
+ while ((ch = getopt(argc, argv, "cfHSp:P:ru:o:s:l:t:l:m:R:T:")) != -1) {
switch (ch) {
case 'c':
nochdir = 0;
@@ -107,6 +113,9 @@ main(int argc, char *argv[])
case 'f':
noclose = 0;
break;
+ case 'H':
+ log_reopen = 1;
+ break;
case 'l':
logfac = get_log_mapping(optarg, facilitynames);
if (logfac == -1)
@@ -168,7 +177,7 @@ main(int argc, char *argv[])
title = argv[0];
if (outfn) {
- outfd = open(outfn, O_CREAT | O_WRONLY | O_APPEND | O_CLOEXEC, 0600);
+ outfd = open_log(outfn);
if (outfd == -1)
err(7, "open");
}
@@ -201,7 +210,7 @@ main(int argc, char *argv[])
*/
pid = -1;
if (pidfile || ppidfile || restart || outfd != -1 || dosyslog) {
- struct sigaction act_term, act_chld;
+ struct sigaction act_term, act_chld, act_hup;
/* Avoid PID racing with SIGCHLD and SIGTERM. */
memset(&act_term, 0, sizeof(act_term));
@@ -214,6 +223,10 @@ main(int argc, char *argv[])
sigemptyset(&act_chld.sa_mask);
sigaddset(&act_chld.sa_mask, SIGTERM);
+ memset(&act_hup, 0, sizeof(act_hup));
+ act_hup.sa_handler = handle_hup;
+ sigemptyset(&act_hup.sa_mask);
+
/* Block these when avoiding racing before sigsuspend(). */
sigemptyset(&mask_susp);
sigaddset(&mask_susp, SIGTERM);
@@ -251,6 +264,12 @@ main(int argc, char *argv[])
logpar.dosyslog = dosyslog;
logpar.logpri = logpri;
logpar.noclose = noclose;
+ logpar.outfn = outfn;
+ if (log_reopen && outfd >= 0 &&
+ sigaction(SIGHUP, &act_hup, NULL) == -1) {
+ warn("sigaction");
+ goto exit;
+ }
restart:
if (pipe(pfd))
err(1, "pipe");
@@ -465,6 +484,8 @@ listen_child(int fd, struct log_params *logpar)
assert(logpar);
assert(bytes_read < LBUF_SIZE - 1);
+ if (do_log_reopen)
+ reopen_log(logpar);
rv = read(fd, buf + bytes_read, LBUF_SIZE - bytes_read - 1);
if (rv > 0) {
unsigned char *cp;
@@ -543,9 +564,9 @@ handle_term(int signo)
}
static void
-handle_chld(int signo)
+handle_chld(int signo __unused)
{
- (void)signo;
+
for (;;) {
int rv = waitpid(-1, NULL, WNOHANG);
if (pid == rv) {
@@ -558,11 +579,37 @@ handle_chld(int signo)
}
}
+static void
+handle_hup(int signo __unused)
+{
+
+ do_log_reopen = 1;
+}
+
+static int
+open_log(const char *outfn)
+{
+
+ return open(outfn, O_CREAT | O_WRONLY | O_APPEND | O_CLOEXEC, 0600);
+}
+
+static void
+reopen_log(struct log_params *lpp)
+{
+ int outfd;
+
+ do_log_reopen = 0;
+ outfd = open_log(lpp->outfn);
+ if (lpp->outfd >= 0)
+ close(lpp->outfd);
+ lpp->outfd = outfd;
+}
+
static void
usage(void)
{
(void)fprintf(stderr,
- "usage: daemon [-cfrS] [-p child_pidfile] [-P supervisor_pidfile]\n"
+ "usage: daemon [-cfHrS] [-p child_pidfile] [-P supervisor_pidfile]\n"
" [-u user] [-o output_file] [-t title]\n"
" [-l syslog_facility] [-s syslog_priority]\n"
" [-T syslog_tag] [-m output_mask] [-R restart_delay_secs]\n"
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