[syslinux] [PATCH] tftpd.c: write a pid file in standalone mode

[Ferenc Wagner]

The default path is /var/run/tftpd-hpa.pid, which can be overridden
by the newly introduced -P option.  On normal termination (SIGTERM
or SIGINT) the pid file is automatically removed.

Moved setting the umask later, right before entering the select loop,
so that it does not affect the permissions of the pid file.

Signed-off-by: Ferenc Wagner <wferi at niif.hu>
---
 tftpd/tftpd.c |   38 ++++++++++++++++++++++++++++++++++----
 1 files changed, 34 insertions(+), 4 deletions(-)

diff --git a/tftpd/tftpd.c b/tftpd/tftpd.c
index ff39c85..d38a961 100644
--- a/tftpd/tftpd.c
+++ b/tftpd/tftpd.c
@@ -144,6 +144,13 @@ static void handle_sighup(int sig)
     caught_sighup = 1;
 }
 
+/* Handle exit requests by SIGTERM and SIGINT */
+static volatile sig_atomic_t exit_signal = 0;
+static void handle_exit(int sig)
+{
+    exit_signal = sig;
+}
+
 /* Handle timeout signal or timeout event */
 void timer(int sig)
 {
@@ -318,9 +325,10 @@ static struct option long_options[] = {
     { "retransmit",  1, NULL, 'T' },
     { "port-range",  1, NULL, 'R' },
     { "map-file",    1, NULL, 'm' },
+    { "pidfile",     1, NULL, 'P' },
     { NULL, 0, NULL, 0 }
 };
-static const char short_options[] = "46cspvVlLa:B:u:U:r:t:T:R:m:";
+static const char short_options[] = "46cspvVlLa:B:u:U:r:t:T:R:m:P:";
 
 int main(int argc, char **argv)
 {
@@ -352,6 +360,7 @@ int main(int argc, char **argv)
 #ifdef WITH_REGEX
     char *rewrite_file = NULL;
 #endif
+    const char *pidfile = "/var/run/tftpd-hpa.pid";
     u_short tp_opcode;
 
     /* basename() is way too much of a pain from a portability standpoint */
@@ -475,6 +484,9 @@ int main(int argc, char **argv)
             printf("%s\n", TFTPD_CONFIG_STR);
             exit(0);
             break;
+        case 'P':
+            pidfile = optarg;
+            break;
         default:
             syslog(LOG_ERR, "Unknown option: '%c'", optopt);
             break;
@@ -507,9 +519,6 @@ int main(int argc, char **argv)
         exit(EX_NOUSER);
     }
 
-    if (spec_umask || !unixperms)
-        umask(my_umask);
-
 #ifdef WITH_REGEX
     if (rewrite_file)
         rewrite_rules = read_remap_rules(rewrite_file);
@@ -517,6 +526,7 @@ int main(int argc, char **argv)
 
     /* If we're running standalone, set up the input port */
     if (standalone) {
+        FILE *pf;
 #ifdef HAVE_IPV6
         if (ai_fam != AF_INET6) {
 #endif
@@ -702,6 +712,14 @@ int main(int argc, char **argv)
             syslog(LOG_ERR, "cannot daemonize: %m");
             exit(EX_OSERR);
         }
+        set_signal(SIGTERM, handle_exit, 0);
+        set_signal(SIGINT,  handle_exit, 0);
+        pf = fopen (pidfile, "w");
+        if (!pf
+            || fprintf(pf, "%d\n", getpid()) < 0
+            || fclose(pf)) {
+	    syslog(LOG_ERR, "cannot write pid file '%s': %m", pidfile);
+        }
         if (fd6 > fd4)
             fdmax = fd6;
         else
@@ -734,11 +752,23 @@ int main(int argc, char **argv)
        lose packets as a result. */
     set_signal(SIGHUP, handle_sighup, 0);
 
+    if (spec_umask || !unixperms)
+        umask(my_umask);
+
     while (1) {
         fd_set readset;
         struct timeval tv_waittime;
         int rv;
 
+        if (exit_signal) { /* happens in standalone mode only */
+            if (unlink(pidfile)) {
+                syslog(LOG_ERR, "error removing pid file '%s': %m", pidfile);
+                exit(EX_OSERR);
+            } else {
+                exit(0);
+            }
+	}
+
         if (caught_sighup) {
             caught_sighup = 0;
             if (standalone) {
-- 
1.5.6.5