Fix unportable code in SockAddr_cidr_mask: you can't assume that

shifting left by full word width gives zero.  Per bug report from
Tyson Thomson.

diff --git a/src/backend/libpq/ip.c b/src/backend/libpq/ip.c
index 74bcda8eb1b64ceaf7abd9fa0323ce423cd581ba..539b140e053293c9e712b9cf26cbbdcb57ddec6b 100644 (file)
--- a/src/backend/libpq/ip.c
+++ b/src/backend/libpq/ip.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *   $PostgreSQL: pgsql/src/backend/libpq/ip.c,v 1.29 2004/09/27 23:24:30 momjian Exp $
+ *   $PostgreSQL: pgsql/src/backend/libpq/ip.c,v 1.30 2004/11/08 01:54:40 tgl Exp $
  *
  * This file and the IPV6 implementation were initially provided by
  * Nigel Kukard <nkukard@lbsd.net>, Linux Based Systems Design
@@ -340,37 +340,40 @@ SockAddr_cidr_mask(struct sockaddr_storage * mask, char *numbits, int family)
 {
    long        bits;
    char       *endptr;
-   struct sockaddr_in mask4;
-
-#ifdef HAVE_IPV6
-   struct sockaddr_in6 mask6;
-#endif
 
    bits = strtol(numbits, &endptr, 10);
 
    if (*numbits == '\0' || *endptr != '\0')
        return -1;
 
-   if ((bits < 0) || (family == AF_INET && bits > 32)
-#ifdef HAVE_IPV6
-       || (family == AF_INET6 && bits > 128)
-#endif
-       )
-       return -1;
-
    switch (family)
    {
        case AF_INET:
-           mask4.sin_addr.s_addr =
-               htonl((0xffffffffUL << (32 - bits))
-                     & 0xffffffffUL);
-           memcpy(mask, &mask4, sizeof(mask4));
-           break;
+           {
+               struct sockaddr_in mask4;
+               long        maskl;
+
+               if (bits < 0 || bits > 32)
+                   return -1;
+               /* avoid "x << 32", which is not portable */
+               if (bits > 0)
+                   maskl = (0xffffffffUL << (32 - (int) bits))
+                       & 0xffffffffUL;
+               else
+                   maskl = 0;
+               mask4.sin_addr.s_addr = htonl(maskl);
+               memcpy(mask, &mask4, sizeof(mask4));
+               break;
+           }
+
 #ifdef HAVE_IPV6
        case AF_INET6:
            {
+               struct sockaddr_in6 mask6;
                int         i;
 
+               if (bits < 0 || bits > 128)
+                   return -1;
                for (i = 0; i < 16; i++)
                {
                    if (bits <= 0)
@@ -380,7 +383,7 @@ SockAddr_cidr_mask(struct sockaddr_storage * mask, char *numbits, int family)
                    else
                    {
                        mask6.sin6_addr.s6_addr[i] =
-                           (0xff << (8 - bits)) & 0xff;
+                           (0xff << (8 - (int) bits)) & 0xff;
                    }
                    bits -= 8;
                }