syslogd: support "symlink to symlink" for /dev/log; reduce stack usage

[platform/upstream/busybox.git] / sysklogd / syslogd.c

diff --git a/sysklogd/syslogd.c b/sysklogd/syslogd.c
index da63ced..e3abcc7 100644 (file)
--- a/sysklogd/syslogd.c
+++ b/sysklogd/syslogd.c
@@ -467,13 +467,39 @@ static void do_mark(int sig)
 }
 #endif
 
-static void do_syslogd(void) ATTRIBUTE_NORETURN;
-static void do_syslogd(void)
+/* Don't inline: prevent struct sockaddr_un to take up space on stack
+ * permanently */
+static NOINLINE int create_socket(void)
 {
        struct sockaddr_un sunx;
        int sock_fd;
        char *dev_log_name;
 
+       memset(&sunx, 0, sizeof(sunx));
+       sunx.sun_family = AF_UNIX;
+
+       /* Unlink old /dev/log or object it points to. */
+       /* (if it exists, bind will fail) */
+       strcpy(sunx.sun_path, "/dev/log");
+       dev_log_name = xmalloc_follow_symlinks("/dev/log");
+       if (dev_log_name) {
+               safe_strncpy(sunx.sun_path, dev_log_name, sizeof(sunx.sun_path));
+               free(dev_log_name);
+       }
+       unlink(sunx.sun_path);
+
+       sock_fd = xsocket(AF_UNIX, SOCK_DGRAM, 0);
+       xbind(sock_fd, (struct sockaddr *) &sunx, sizeof(sunx));
+       chmod("/dev/log", 0666);
+
+       return sock_fd;
+}
+
+static void do_syslogd(void) ATTRIBUTE_NORETURN;
+static void do_syslogd(void)
+{
+       int sock_fd;
+
        /* Set up signal handlers */
        signal(SIGINT, quit_signal);
        signal(SIGTERM, quit_signal);
@@ -487,36 +513,8 @@ static void do_syslogd(void)
        signal(SIGALRM, do_mark);
        alarm(G.markInterval);
 #endif
-       remove_pidfile("/var/run/syslogd.pid");
-
-       memset(&sunx, 0, sizeof(sunx));
-       sunx.sun_family = AF_UNIX;
-       strcpy(sunx.sun_path, "/dev/log");
+       sock_fd = create_socket();
 
-       /* Unlink old /dev/log or object it points to. */
-       /* (if it exists, bind will fail) */
-       logmode = LOGMODE_NONE;
-       dev_log_name = xmalloc_readlink_or_warn("/dev/log");
-       logmode = LOGMODE_STDIO;
-       if (dev_log_name) {
-               int fd = xopen(".", O_NONBLOCK);
-               xchdir("/dev");
-               /* we do not check whether this is a link also */
-               unlink(dev_log_name);
-               fchdir(fd);
-               close(fd);
-               safe_strncpy(sunx.sun_path, dev_log_name, sizeof(sunx.sun_path));
-               free(dev_log_name);
-       } else {
-               unlink("/dev/log");
-       }
-
-       sock_fd = xsocket(AF_UNIX, SOCK_DGRAM, 0);
-       xbind(sock_fd, (struct sockaddr *) &sunx, sizeof(sunx));
-
-       if (chmod("/dev/log", 0666) < 0) {
-               bb_perror_msg_and_die("cannot set permission on /dev/log");
-       }
        if (ENABLE_FEATURE_IPC_SYSLOG && (option_mask32 & OPT_circularlog)) {
                ipcsyslog_init();
        }