tests: run the TFTP test server on a dynamic port number

Picking a dynamic unused port is better than a fixed to avoid the
collision risk.

Closes #5265

1 files changed, 60 insertions, 6 deletions

diff --git a/tests/server/tftpd.c b/tests/server/tftpd.c
index 9972ab0e4..46b09b562 100644
--- a/tests/server/tftpd.c
+++ b/tests/server/tftpd.c
@@ -210,6 +210,7 @@ static const char *ipv_inuse = "IPv4";
 
 const  char *serverlogfile = DEFAULT_LOGFILE;
 static const char *pidname = ".tftpd.pid";
+static const char *portfile = NULL;
 static int serverlogslocked = 0;
 static int wrotepidfile = 0;
 
@@ -574,6 +575,11 @@ int main(int argc, char **argv)
       if(argc>arg)
         pidname = argv[arg++];
     }
+    else if(!strcmp("--portfile", argv[arg])) {
+      arg++;
+      if(argc>arg)
+        portfile = argv[arg++];
+    }
     else if(!strcmp("--logfile", argv[arg])) {
       arg++;
       if(argc>arg)
@@ -598,12 +604,6 @@ int main(int argc, char **argv)
       if(argc>arg) {
         char *endptr;
         unsigned long ulnum = strtoul(argv[arg], &endptr, 10);
-        if((endptr != argv[arg] + strlen(argv[arg])) ||
-           (ulnum < 1025UL) || (ulnum > 65535UL)) {
-          fprintf(stderr, "tftpd: invalid --port argument (%s)\n",
-                  argv[arg]);
-          return 0;
-        }
         port = curlx_ultous(ulnum);
         arg++;
       }
@@ -690,12 +690,64 @@ int main(int argc, char **argv)
     goto tftpd_cleanup;
   }
 
+  if(!port) {
+    /* The system was supposed to choose a port number, figure out which
+       port we actually got and update the listener port value with it. */
+    curl_socklen_t la_size;
+    srvr_sockaddr_union_t localaddr;
+#ifdef ENABLE_IPV6
+    if(!use_ipv6)
+#endif
+      la_size = sizeof(localaddr.sa4);
+#ifdef ENABLE_IPV6
+    else
+      la_size = sizeof(localaddr.sa6);
+#endif
+    memset(&localaddr.sa, 0, (size_t)la_size);
+    if(getsockname(sock, &localaddr.sa, &la_size) < 0) {
+      error = SOCKERRNO;
+      logmsg("getsockname() failed with error: (%d) %s",
+             error, strerror(error));
+      sclose(sock);
+      return CURL_SOCKET_BAD;
+    }
+    switch(localaddr.sa.sa_family) {
+    case AF_INET:
+      port = ntohs(localaddr.sa4.sin_port);
+      break;
+#ifdef ENABLE_IPV6
+    case AF_INET6:
+      port = ntohs(localaddr.sa6.sin6_port);
+      break;
+#endif
+    default:
+      break;
+    }
+    if(!port) {
+      /* Real failure, listener port shall not be zero beyond this point. */
+      logmsg("Apparently getsockname() succeeded, with listener port zero.");
+      logmsg("A valid reason for this failure is a binary built without");
+      logmsg("proper network library linkage. This might not be the only");
+      logmsg("reason, but double check it before anything else.");
+      result = 2;
+      goto tftpd_cleanup;
+    }
+  }
+
   wrotepidfile = write_pidfile(pidname);
   if(!wrotepidfile) {
     result = 1;
     goto tftpd_cleanup;
   }
 
+  if(portfile) {
+    wrotepidfile = write_portfile(portfile, port);
+    if(!wrotepidfile) {
+      result = 1;
+      goto tftpd_cleanup;
+    }
+  }
+
   logmsg("Running %s version on port UDP/%d", ipv_inuse, (int)port);
 
   for(;;) {
@@ -800,6 +852,8 @@ tftpd_cleanup:
 
   if(wrotepidfile)
     unlink(pidname);
+  if(portfile)
+    unlink(portfile);
 
   if(serverlogslocked) {
     serverlogslocked = 0;