socket-proxyd: Add --listener option for listener/destination pairs.

1 files changed, 42 insertions, 21 deletions

diff --git a/src/socket-proxy/socket-proxyd.c b/src/socket-proxy/socket-proxyd.c
index 432558d19..362e8aae9 100644
--- a/src/socket-proxy/socket-proxyd.c
+++ b/src/socket-proxy/socket-proxyd.c
@@ -66,6 +66,7 @@ typedef struct Connection {
 } Connection;
 
 static const char *arg_remote_host = NULL;
+static int arg_listener = -1;
 
 static void connection_free(Connection *c) {
         assert(c);
@@ -554,8 +555,9 @@ static int help(void) {
         printf("%s [HOST:PORT]\n"
                "%s [SOCKET]\n\n"
                "Bidirectionally proxy local sockets to another (possibly remote) socket.\n\n"
-               "  -h --help              Show this help\n"
-               "     --version           Show package version\n",
+               "  -l --listener=FD  Listen on a specific, single file descriptor.\n"
+               "  -h --help         Show this help\n"
+               "     --version      Show package version\n",
                program_invocation_short_name,
                program_invocation_short_name);
 
@@ -565,22 +567,22 @@ static int help(void) {
 static int parse_argv(int argc, char *argv[]) {
 
         enum {
-                ARG_VERSION = 0x100,
-                ARG_IGNORE_ENV
+                ARG_VERSION = 0x100
         };
 
         static const struct option options[] = {
-                { "help",       no_argument, NULL, 'h'           },
-                { "version",    no_argument, NULL, ARG_VERSION   },
+                { "help",     no_argument,       NULL, 'h'         },
+                { "version",  no_argument,       NULL, ARG_VERSION },
+                { "listener", required_argument, NULL, 'l'         },
                 {}
         };
 
-        int c;
+        int c, fd;
 
         assert(argc >= 0);
         assert(argv);
 
-        while ((c = getopt_long(argc, argv, "h", options, NULL)) >= 0) {
+        while ((c = getopt_long(argc, argv, "hl:", options, NULL)) >= 0) {
 
                 switch (c) {
 
@@ -592,6 +594,18 @@ static int parse_argv(int argc, char *argv[]) {
                         puts(SYSTEMD_FEATURES);
                         return 0;
 
+                case 'l':
+                        if (safe_atoi(optarg, &fd) < 0) {
+                                log_error("Failed to parse listener file descriptor: %s", optarg);
+                                return -EINVAL;
+                        }
+                        if (fd < SD_LISTEN_FDS_START) {
+                                log_error("Listener file descriptor must be at least %d.", SD_LISTEN_FDS_START);
+                                return -EINVAL;
+                        }
+                        arg_listener = fd;
+                        break;
+
                 case '?':
                         return -EINVAL;
 
@@ -632,19 +646,26 @@ int main(int argc, char *argv[]) {
                 goto finish;
         }
 
-        n = sd_listen_fds(1);
-        if (n < 0) {
-                log_error("Failed to receive sockets from parent.");
-                r = n;
-                goto finish;
-        } else if (n == 0) {
-                log_error("Didn't get any sockets passed in.");
-                r = -EINVAL;
-                goto finish;
-        }
-
-        for (fd = SD_LISTEN_FDS_START; fd < SD_LISTEN_FDS_START + n; fd++) {
-                r = add_listen_socket(&context, event, fd);
+        if (arg_listener == -1) {
+                n = sd_listen_fds(1);
+                if (n < 0) {
+                        log_error("Failed to receive sockets from parent.");
+                        r = n;
+                        goto finish;
+                } else if (n == 0) {
+                        log_error("Didn't get any sockets passed in.");
+                        r = -EINVAL;
+                        goto finish;
+                }
+                log_info("Listening on %d inherited socket(s), starting with fd=%d.", n, SD_LISTEN_FDS_START);
+                for (fd = SD_LISTEN_FDS_START; fd < SD_LISTEN_FDS_START + n; fd++) {
+                        r = add_listen_socket(&context, event, fd);
+                        if (r < 0)
+                                goto finish;
+                }
+        } else {
+                log_info("Listening on single inherited socket fd=%d.", arg_listener);
+                r = add_listen_socket(&context, event, arg_listener);
                 if (r < 0)
                         goto finish;
         }