Gitweb:
https://sourceware.org/git/?p=lvm2.git;a=commitdiff;h=b3b1e788e16c77f6784...
Commit: b3b1e788e16c77f6784f30b8e984f68792f8fa1a
Parent: 5de944420224f3b629e843f9c190132ed9ff3dca
Author: Zdenek Kabelac <zkabelac(a)redhat.com>
AuthorDate: Fri Aug 25 11:55:38 2017 +0200
Committer: Zdenek Kabelac <zkabelac(a)redhat.com>
CommitterDate: Fri Aug 25 14:20:57 2017 +0200
daemonize: more unified code
ATM we have several instances of daemonizing code.
Each has its 'special' logic so not completely easy
to unify them all into a single routine.
Start to unify them and use one strategy for rediricting
all input/outpus to /dev/null - use 'dup2' function for this
and open /dev/null before fork to make sure it's available.
---
daemons/clvmd/clvmd.c | 26 ++++++++++----------------
libdaemon/server/daemon-server.c | 21 +++++++++++++++------
2 files changed, 25 insertions(+), 22 deletions(-)
diff --git a/daemons/clvmd/clvmd.c b/daemons/clvmd/clvmd.c
index 79aa939..46f5f44 100644
--- a/daemons/clvmd/clvmd.c
+++ b/daemons/clvmd/clvmd.c
@@ -1105,31 +1105,25 @@ static void be_daemon(int timeout)
break;
default: /* Parent */
+ (void) close(devnull);
(void) close(child_pipe[1]);
- wait_for_child(child_pipe[0], timeout);
+ wait_for_child(child_pipe[0], timeout); /* noreturn */
}
/* Detach ourself from the calling environment */
- if (close(0) || close(1) || close(2)) {
- perror("Error closing terminal FDs");
- exit(4);
- }
- setsid();
+ (void) dup2(devnull, STDIN_FILENO);
+ (void) dup2(devnull, STDOUT_FILENO);
+ (void) dup2(devnull, STDERR_FILENO);
+
+ if (devnull > STDERR_FILENO)
+ (void) close(devnull);
- if (dup2(devnull, 0) < 0 || dup2(devnull, 1) < 0
- || dup2(devnull, 2) < 0) {
- perror("Error setting terminal FDs to /dev/null");
- log_error("Error setting terminal FDs to /dev/null: %m");
- exit(5);
- }
- if ((devnull > STDERR_FILENO) && close(devnull)) {
- log_sys_error("close", "/dev/null");
- exit(7);
- }
if (chdir("/")) {
log_error("Error setting current directory to /: %m");
exit(6);
}
+
+ setsid();
}
static int verify_message(char *buf, int len)
diff --git a/libdaemon/server/daemon-server.c b/libdaemon/server/daemon-server.c
index 6fdf195..0950c2e 100644
--- a/libdaemon/server/daemon-server.c
+++ b/libdaemon/server/daemon-server.c
@@ -334,6 +334,11 @@ static void _daemonise(daemon_state s)
struct timeval tval;
sigset_t my_sigset;
+ if ((fd = open("/dev/null", O_RDWR)) == -1) {
+ fprintf(stderr, "Unable to open /dev/null.\n");
+ exit(EXIT_FAILURE);
+ }
+
sigemptyset(&my_sigset);
if (sigprocmask(SIG_SETMASK, &my_sigset, NULL) < 0) {
fprintf(stderr, "Unable to restore signals.\n");
@@ -350,6 +355,7 @@ static void _daemonise(daemon_state s)
break;
default:
+ (void) close(fd);
/* Wait for response from child */
while (!waitpid(pid, &child_status, WNOHANG) && !_shutdown_requested) {
tval.tv_sec = 0;
@@ -374,12 +380,20 @@ static void _daemonise(daemon_state s)
if (chdir("/"))
exit(1);
+ (void) dup2(fd, STDIN_FILENO);
+ (void) dup2(fd, STDOUT_FILENO);
+ (void) dup2(fd, STDERR_FILENO);
+
+ if (fd > STDERR_FILENO)
+ (void) close(fd);
+
+ /* Switch to sysconf(_SC_OPEN_MAX) ?? */
if (getrlimit(RLIMIT_NOFILE, &rlim) < 0)
fd = 256; /* just have to guess */
else
fd = rlim.rlim_cur;
- for (--fd; fd >= 0; fd--) {
+ for (--fd; fd > STDERR_FILENO; fd--) {
#ifdef __linux__
/* Do not close fds preloaded by systemd! */
if (_systemd_activation && fd == SD_FD_SOCKET_SERVER)
@@ -388,11 +402,6 @@ static void _daemonise(daemon_state s)
(void) close(fd);
}
- if ((open("/dev/null", O_RDONLY) < 0) ||
- (open("/dev/null", O_WRONLY) < 0) ||
- (open("/dev/null", O_WRONLY) < 0))
- exit(1);
-
setsid();
}