daemon.c: fix segfault on OS X

On OS X (and maybe other unices), getaddrinfo(3) returns NULL
in the ai_canonname field if it's called with an IP address for
the hostname. We'll now use the IP address for the hostname if
ai_canonname was NULL, this also matches the behaviour on Linux.

steps to reproduce:
$ git daemon --export-all
$ git clone git://127.0.0.1/frotz
=> git daemon's fork (silently) segfaults.

Remove the pointless loop while at it. There is only one iteration
because of the break; on the last line and there are no continues.

Signed-off-by: Benjamin Kramer <benny.kra@googlemail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/daemon.c b/daemon.c
index 13401f1baf57dc87a7a95bd778f4e1becbdbe323..daa4c8e8c95924c6fb446884b3ed44c454425b54 100644 (file)
--- a/daemon.c
+++ b/daemon.c
@@ -444,27 +444,27 @@ static void parse_extra_args(char *extra_args, int buflen)
        if (hostname) {
 #ifndef NO_IPV6
                struct addrinfo hints;
-               struct addrinfo *ai, *ai0;
+               struct addrinfo *ai;
                int gai;
                static char addrbuf[HOST_NAME_MAX + 1];
 
                memset(&hints, 0, sizeof(hints));
                hints.ai_flags = AI_CANONNAME;
 
-               gai = getaddrinfo(hostname, 0, &hints, &ai0);
+               gai = getaddrinfo(hostname, 0, &hints, &ai);
                if (!gai) {
-                       for (ai = ai0; ai; ai = ai->ai_next) {
-                               struct sockaddr_in *sin_addr = (void *)ai->ai_addr;
-
-                               inet_ntop(AF_INET, &sin_addr->sin_addr,
-                                         addrbuf, sizeof(addrbuf));
-                               free(canon_hostname);
-                               canon_hostname = xstrdup(ai->ai_canonname);
-                               free(ip_address);
-                               ip_address = xstrdup(addrbuf);
-                               break;
-                       }
-                       freeaddrinfo(ai0);
+                       struct sockaddr_in *sin_addr = (void *)ai->ai_addr;
+
+                       inet_ntop(AF_INET, &sin_addr->sin_addr,
+                                 addrbuf, sizeof(addrbuf));
+                       free(ip_address);
+                       ip_address = xstrdup(addrbuf);
+
+                       free(canon_hostname);
+                       canon_hostname = xstrdup(ai->ai_canonname ?
+                                                ai->ai_canonname : ip_address);
+
+                       freeaddrinfo(ai);
                }
 #else
                struct hostent *hent;