don't reenter get_udevd_msg() if message is ignored

[elogind.git] / udevd.c

diff --git a/udevd.c b/udevd.c
index 79d3e825501a51ae1de3967da0277893091b061d..c75141f9fa36b6a06f30672c07bb24fff412ffef 100644 (file)
--- a/udevd.c
+++ b/udevd.c
@@ -55,7 +55,7 @@ static int udevd_sock;
 static int uevent_netlink_sock;
 static pid_t sid;
 
-static int pipefds[2] = {-1, -1};
+static int signal_pipe[2] = {-1, -1};
 static volatile int sigchilds_waiting;
 static volatile int run_msg_q;
 static volatile int sig_flag;
@@ -113,7 +113,7 @@ static void msg_queue_insert(struct uevent_msg *msg)
 
        if (msg->seqnum == 0) {
                dbg("no SEQNUM, move straight to the exec queue");
-               list_add(&msg->node, &exec_list);
+               list_add_tail(&msg->node, &exec_list);
                run_exec_q = 1;
                return;
        }
@@ -636,8 +636,6 @@ static struct uevent_msg *get_netlink_msg(void)
 
 static void asmlinkage sig_handler(int signum)
 {
-       int rc;
-
        switch (signum) {
                case SIGINT:
                case SIGTERM:
@@ -653,14 +651,8 @@ static void asmlinkage sig_handler(int signum)
                        break;
        }
 
-       /* if pipe is empty, write to pipe to force select to return,
-        * which will wakeup our mainloop
-        */
-       if (!sig_flag) {
-               rc = write(pipefds[1], &signum, sizeof(signum));
-               if (rc >= 0)
-                       sig_flag = 1;
-       }
+       /* write to pipe, which will wakeup select() in our mainloop */
+       write(signal_pipe[WRITE_END], "", 1);
 }
 
 static void udev_done(int pid)
@@ -777,7 +769,23 @@ int main(int argc, char *argv[], char *envp[])
        int daemonize = 0;
        int i;
 
+       /* set std fd's to /dev/null, if the kernel forks us, we don't have them at all */
+       devnull = open("/dev/null", O_RDWR);
+       if (devnull >= 0)  {
+               if (devnull != STDIN_FILENO)
+                       dup2(devnull, STDIN_FILENO);
+               if (devnull != STDOUT_FILENO)
+                       dup2(devnull, STDOUT_FILENO);
+               if (devnull != STDERR_FILENO)
+                       dup2(devnull, STDERR_FILENO);
+               if (devnull > STDERR_FILENO)
+                       close(devnull);
+       }
+
        logging_init("udevd");
+       if (devnull < 0)
+               err("fatal, could not open /dev/null");
+
        udev_init_config();
        dbg("version %s", UDEV_VERSION);
 
@@ -825,36 +833,26 @@ int main(int argc, char *argv[], char *envp[])
        /* set a reasonable scheduling priority for the daemon */
        setpriority(PRIO_PROCESS, 0, UDEVD_PRIORITY);
 
-       /* Set fds to dev/null */
-       devnull = open( "/dev/null", O_RDWR );
-       if (devnull > 0)  {
-               dup2(devnull, STDIN_FILENO);
-               dup2(devnull, STDOUT_FILENO);
-               dup2(devnull, STDERR_FILENO);
-               close(devnull);
-       } else
-               err("error opening /dev/null %s", strerror(errno));
-
        /* setup signal handler pipe */
-       retval = pipe(pipefds);
+       retval = pipe(signal_pipe);
        if (retval < 0) {
                err("error getting pipes: %s", strerror(errno));
                goto exit;
        }
-       retval = fcntl(pipefds[0], F_SETFL, O_NONBLOCK);
+       retval = fcntl(signal_pipe[READ_END], F_SETFL, O_NONBLOCK);
        if (retval < 0) {
                err("error fcntl on read pipe: %s", strerror(errno));
                goto exit;
        }
-       retval = fcntl(pipefds[0], F_SETFD, FD_CLOEXEC);
+       retval = fcntl(signal_pipe[READ_END], F_SETFD, FD_CLOEXEC);
        if (retval < 0)
                err("error fcntl on read pipe: %s", strerror(errno));
-       retval = fcntl(pipefds[1], F_SETFL, O_NONBLOCK);
+       retval = fcntl(signal_pipe[WRITE_END], F_SETFL, O_NONBLOCK);
        if (retval < 0) {
                err("error fcntl on write pipe: %s", strerror(errno));
                goto exit;
        }
-       retval = fcntl(pipefds[1], F_SETFD, FD_CLOEXEC);
+       retval = fcntl(signal_pipe[WRITE_END], F_SETFD, FD_CLOEXEC);
        if (retval < 0)
                err("error fcntl on write pipe: %s", strerror(errno));
 
@@ -928,7 +926,7 @@ int main(int argc, char *argv[], char *envp[])
                int fdcount;
 
                FD_ZERO(&readfds);
-               FD_SET(pipefds[0], &readfds);
+               FD_SET(signal_pipe[READ_END], &readfds);
                FD_SET(udevd_sock, &readfds);
                if (uevent_netlink_sock > 0)
                        FD_SET(uevent_netlink_sock, &readfds);
@@ -948,9 +946,8 @@ int main(int argc, char *argv[], char *envp[])
                                if (uevent_netlink_active && msg->type == UDEVD_UEVENT_UDEVSEND && msg->seqnum != 0) {
                                        dbg("skip uevent_helper message, netlink is active");
                                        free(msg);
-                                       continue;
-                               }
-                               msg_queue_insert(msg);
+                               } else
+                                       msg_queue_insert(msg);
                        }
                }
 
@@ -968,16 +965,10 @@ int main(int argc, char *argv[], char *envp[])
                }
 
                /* received a signal, clear our notification pipe */
-               if (FD_ISSET(pipefds[0], &readfds)) {
-                       int sig;
-                       ssize_t rlen;
-
-                       while(1) {
-                               rlen = read(pipefds[0], &sig, sizeof(sig));
-                               if (rlen <= 0)
-                                       break;
-                       }
-                       sig_flag = 0;
+               if (FD_ISSET(signal_pipe[READ_END], &readfds)) {
+                       char buf[256];
+
+                       read(signal_pipe[READ_END], &buf, sizeof(buf));
                }
 
                /* forked child have returned */
@@ -1005,10 +996,10 @@ int main(int argc, char *argv[], char *envp[])
        }
 
 exit:
-       if (pipefds[0] > 0)
-               close(pipefds[0]);
-       if (pipefds[1] > 0)
-               close(pipefds[1]);
+       if (signal_pipe[READ_END] > 0)
+               close(signal_pipe[READ_END]);
+       if (signal_pipe[WRITE_END] > 0)
+               close(signal_pipe[WRITE_END]);
 
        if (udevd_sock > 0)
                close(udevd_sock);