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Diffstat (limited to 'unix')
-rw-r--r--unix/tclUnixSock.c39
1 files changed, 38 insertions, 1 deletions
diff --git a/unix/tclUnixSock.c b/unix/tclUnixSock.c
index 8167077..f7bd0be 100644
--- a/unix/tclUnixSock.c
+++ b/unix/tclUnixSock.c
@@ -1429,7 +1429,7 @@ Tcl_OpenTcpServer(
* clients. */
ClientData acceptProcData) /* Data for the callback. */
{
- int status = 0, sock = -1, reuseaddr = 1, chosenport = 0;
+ int status = 0, sock = -1, reuseaddr = 1, chosenport;
struct addrinfo *addrlist = NULL, *addrPtr; /* socket address */
TcpState *statePtr = NULL;
char channelName[SOCK_CHAN_LENGTH];
@@ -1444,6 +1444,37 @@ Tcl_OpenTcpServer(
enum { LOOKUP, SOCKET, BIND, LISTEN } howfar = LOOKUP;
int my_errno = 0;
+ /*
+ * If we were called with port 0 to listen on a random port number, we
+ * copy the port number from the first member of the addrinfo list to all
+ * subsequent members, so that IPv4 and IPv6 listen on the same port. This
+ * might fail to bind() with EADDRINUSE if a port is free on the first
+ * address family in the list but already used on the other. In this case
+ * we revert everything we've done so far and start from scratch hoping
+ * that next time we'll find a port number that is usable on all address
+ * families. We try this at most MAXRETRY times to avoid an endless loop
+ * if all ports are taken.
+ */
+ int retry = 0;
+#define MAXRETRY 10
+
+ repeat:
+ if (retry > 0) {
+ if (statePtr != NULL) {
+ TcpCloseProc(statePtr, NULL);
+ statePtr = NULL;
+ }
+ if (addrlist != NULL) {
+ freeaddrinfo(addrlist);
+ addrlist = NULL;
+ }
+ if (retry >= MAXRETRY) {
+ goto error;
+ }
+ }
+ retry++;
+ chosenport = 0;
+
if (!TclCreateSocketAddress(interp, &addrlist, myHost, port, 1, &errorMsg)) {
my_errno = errno;
goto error;
@@ -1512,6 +1543,9 @@ Tcl_OpenTcpServer(
}
close(sock);
sock = -1;
+ if (port == 0 && errno == EADDRINUSE) {
+ goto repeat;
+ }
continue;
}
if (port == 0 && chosenport == 0) {
@@ -1535,6 +1569,9 @@ Tcl_OpenTcpServer(
}
close(sock);
sock = -1;
+ if (port == 0 && errno == EADDRINUSE) {
+ goto repeat;
+ }
continue;
}
if (statePtr == NULL) {