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

tests/runtests.pl

@@ -1940,7 +1940,6 @@ sub runftpsserver {
 #
 sub runtftpserver {
     my ($id, $verbose, $ipv6) = @_;
-    my $port = $TFTPPORT;
     my $ip = $HOSTIP;
     my $proto = 'tftp';
     my $ipvnum = 4;
@@ -1954,13 +1953,13 @@ sub runtftpserver {
     if($ipv6) {
         # if IPv6, use a different setup
         $ipvnum = 6;
-        $port = $TFTP6PORT;
         $ip = $HOST6IP;
     }
 
     $server = servername_id($proto, $ipvnum, $idnum);
 
     $pidfile = $serverpidfile{$server};
+    my $portfile = $serverportfile{$server};
 
     # don't retry if the server doesn't work
     if ($doesntrun{$pidfile}) {
@@ -1978,9 +1977,11 @@ sub runtftpserver {
     $logfile = server_logfilename($LOGDIR, $proto, $ipvnum, $idnum);
 
     $flags .= "--verbose " if($debugprotocol);
-    $flags .= "--pidfile \"$pidfile\" --logfile \"$logfile\" ";
+    $flags .= "--pidfile \"$pidfile\" ".
+        "--portfile \"$portfile\" ".
+        "--logfile \"$logfile\" ";
     $flags .= "--id $idnum " if($idnum > 1);
-    $flags .= "--ipv$ipvnum --port $port --srcdir \"$srcdir\"";
+    $flags .= "--ipv$ipvnum --port 0 --srcdir \"$srcdir\"";
 
     my $cmd = "$perl $srcdir/tftpserver.pl $flags";
     my ($tftppid, $pid2) = startnew($cmd, $pidfile, 15, 0);
@@ -1994,6 +1995,8 @@ sub runtftpserver {
         return (0,0);
     }
 
+    my $port = pidfromfile($portfile);
+
     # Server is up. Verify that we can speak to it.
     my $pid3 = verifyserver($proto, $ipvnum, $idnum, $ip, $port);
     if(!$pid3) {
@@ -2007,12 +2010,12 @@ sub runtftpserver {
     $pid2 = $pid3;
 
     if($verbose) {
-        logmsg "RUN: $srvrname server is now running PID $tftppid\n";
+        logmsg "RUN: $srvrname server on PID $tftppid port $port\n";
     }
 
     sleep(1);
 
-    return ($pid2, $tftppid);
+    return ($pid2, $tftppid, $port);
 }
 
 
@@ -3152,13 +3155,9 @@ sub checksystem {
             logmsg sprintf("FTPS/%d ", $FTPSPORT);
             logmsg sprintf("HTTPS/%d ", $HTTPSPORT);
         }
-        logmsg sprintf("TFTP/%d ", $TFTPPORT);
         if($http_ipv6) {
             logmsg sprintf("RTSP-IPv6/%d ", $RTSP6PORT);
         }
-        if($tftp_ipv6) {
-            logmsg sprintf("TFTP-IPv6/%d ", $TFTP6PORT);
-        }
         logmsg sprintf("\n*   SSH/%d ", $SSHPORT);
         logmsg sprintf("SOCKS/%d ", $SOCKSPORT);
         if($httptlssrv) {
@@ -4848,7 +4847,8 @@ sub startservers {
                 stopserver('tftp');
             }
             if(!$run{'tftp'}) {
-                ($pid, $pid2) = runtftpserver("", $verbose);
+                ($pid, $pid2, $TFTPPORT) =
+                    runtftpserver("", $verbose);
                 if($pid <= 0) {
                     return "failed starting TFTP server";
                 }
@@ -4862,7 +4862,8 @@ sub startservers {
                 stopserver('tftp-ipv6');
             }
             if(!$run{'tftp-ipv6'}) {
-                ($pid, $pid2) = runtftpserver("", $verbose, "ipv6");
+                ($pid, $pid2, $TFTP6PORT) =
+                    runtftpserver("", $verbose, "ipv6");
                 if($pid <= 0) {
                     return "failed starting TFTP-IPv6 server";
                 }
@@ -5440,8 +5441,6 @@ if ($gdbthis) {
 $minport         = $base; # original base port number
 $HTTPSPORT       = $base++; # HTTPS (stunnel) server port
 $FTPSPORT        = $base++; # FTPS (stunnel) server port
-$TFTPPORT        = $base++; # TFTP (UDP) port
-$TFTP6PORT       = $base++; # TFTP IPv6 (UDP) port
 $SSHPORT         = $base++; # SSH (SCP/SFTP) port
 $SOCKSPORT       = $base++; # SOCKS port
 $RTSPPORT        = $base++; # RTSP server port

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;

tests/tftpserver.pl

@@ -43,8 +43,9 @@ my $port = 8997;     # just a default
 my $ipvnum = 4;      # default IP version of tftp server
 my $idnum = 1;       # default tftp server instance number
 my $proto = 'tftp';  # protocol the tftp server speaks
-my $pidfile;         # tftp server pid file
-my $logfile;         # tftp server log file
+my $pidfile;
+my $portfile;
+my $logfile;
 my $srcdir;
 my $fork;
 
@@ -59,6 +60,12 @@ while(@ARGV) {
             shift @ARGV;
         }
     }
+    elsif($ARGV[0] eq '--portfile') {
+        if($ARGV[1]) {
+            $portfile = $ARGV[1];
+            shift @ARGV;
+        }
+    }
     elsif($ARGV[0] eq '--logfile') {
         if($ARGV[1]) {
             $logfile = $ARGV[1];
@@ -108,7 +115,9 @@ if(!$logfile) {
     $logfile = server_logfilename($logdir, $proto, $ipvnum, $idnum);
 }
 
-$flags .= "--pidfile \"$pidfile\" --logfile \"$logfile\" ";
+$flags .= "--pidfile \"$pidfile\" ".
+    "--portfile \"$portfile\" ".
+    "--logfile \"$logfile\" ";
 $flags .= "--ipv$ipvnum --port $port --srcdir \"$srcdir\"";
 
 exec("server/tftpd".exe_ext('SRV')." $flags");