add --listen-backlog option in munged

src/munged/conf.c

@@ -78,7 +78,8 @@
 #define OPT_SEED_FILE           268
 #define OPT_TRUSTED_GROUP       269
 #define OPT_ORIGIN              270
-#define OPT_LAST                271
+#define OPT_LISTEN_BACKLOG      271
+#define OPT_LAST                272
 
 const char * const short_opts = ":hLVfFMsS:v";
 
@@ -102,6 +103,7 @@ struct option long_opts[] = {
     { "group-check-mtime", required_argument, NULL, OPT_GROUP_CHECK   },
     { "group-update-time", required_argument, NULL, OPT_GROUP_UPDATE  },
     { "key-file",          required_argument, NULL, OPT_KEY_FILE      },
+    { "listen-backlog",    required_argument, NULL, OPT_LISTEN_BACKLOG},
     { "log-file",          required_argument, NULL, OPT_LOG_FILE      },
     { "max-ttl",           required_argument, NULL, OPT_MAX_TTL       },
     { "num-threads",       required_argument, NULL, OPT_NUM_THREADS   },
@@ -178,6 +180,7 @@ create_conf (void)
     conf->config_name = NULL;
     conf->lockfile_fd = -1;
     conf->lockfile_name = NULL;
+    conf->listen_backlog = MUNGE_SOCKET_BACKLOG;
 
     _conf_set_cwd (conf);
 
@@ -407,6 +410,25 @@ parse_cmdline (conf_t conf, int argc, char **argv)
                 _conf_set_string (&conf->key_name, optarg, conf->cwd,
                         "key-file name");
                 break;
+            case OPT_LISTEN_BACKLOG:
+                errno = 0;
+                l = strtol (optarg, &p, 10);
+                if (((errno == ERANGE) && ((l == LONG_MIN) || (l == LONG_MAX)))
+                        || (optarg == p) || (*p != '\0')
+                        || (l < -1) || (l > INT_MAX)) {
+                    log_err (EMUNGE_SNAFU, LOG_ERR,
+                        "Invalid value \"%s\" for listen-backlog", optarg);
+                }
+                else if (l == 0) {
+                    conf->listen_backlog = MUNGE_SOCKET_BACKLOG;
+                }
+                else if (l == -1) {
+                    conf->listen_backlog = SOMAXCONN;
+                }
+                else {
+                    conf->listen_backlog = l;
+                }
+                break;
             case OPT_LOG_FILE:
                 _conf_set_string (&conf->logfile_name, optarg, conf->cwd,
                         "log-file name");
@@ -751,6 +773,9 @@ _conf_display_help (char *prog)
     printf ("  %*s %s [%s]\n", w, "--key-file=PATH",
             "Specify key file", MUNGE_KEYFILE_PATH);
 
+    printf ("  %*s %s [%d]\n", w, "--listen-backlog=INT",
+            "Specify listen backlog limit of socket", MUNGE_SOCKET_BACKLOG);
+
     printf ("  %*s %s [%s]\n", w, "--log-file=PATH",
             "Specify log file", MUNGE_LOGFILE_PATH);
 

src/munged/conf.h

@@ -65,6 +65,7 @@ struct conf {
     char           *logfile_name;       /* daemon logfile name               */
     char           *pidfile_name;       /* daemon pidfile name               */
     char           *socket_name;        /* unix domain socket filename       */
+    int             listen_backlog;     /* unix domain socket listen backlog */
     char           *seed_name;          /* random seed filename              */
     char           *key_name;           /* symmetric key filename            */
     unsigned char  *dek_key;            /* subkey for cipher ops             */

src/munged/munged.8.in

@@ -131,6 +131,12 @@ triggered by a \fBSIGHUP\fR).  A value of \-1 causes it to be disabled.
 .BI "\-\-key\-file " path
 Specify an alternate pathname to the key file.
 .TP
+.BI "\-\-listen\-backlog " integer
+Specify the socket's listen backlog limit; note that the kernel may impose
+a lower limit.  A value of 0 uses the software default.  A value of \-1
+specifies \fBSOMAXCONN\fR, the maximum listen backlog queue length defined
+in \fI<sys/socket.h>\fR.
+.TP
 .BI "\-\-log\-file " path
 Specify an alternate pathname to the log file.
 .TP

src/munged/munged.c

@@ -670,12 +670,14 @@ sock_create (conf_t conf)
         log_errno (EMUNGE_SNAFU, LOG_ERR,
             "Failed to bind socket \"%s\"", conf->socket_name);
     }
-    if (listen (sd, MUNGE_SOCKET_BACKLOG) < 0) {
+    if (listen (sd, conf->listen_backlog) < 0) {
         log_errno (EMUNGE_SNAFU, LOG_ERR,
             "Failed to listen on socket \"%s\"", conf->socket_name);
     }
     conf->ld = sd;
     log_msg (LOG_INFO, "Created socket \"%s\"", conf->socket_name);
+    log_msg (LOG_INFO, "Set socket listen backlog to %d",
+            conf->listen_backlog);
     return;
 }