* localaddr.c (krb5_os_localaddr): Dynamically grow buffer used for SIOCGIFCONF

until it appears to have been big enough.  Dynamically grow internal address
pointer array as needed.

git-svn-id: svn://anonsvn.mit.edu/krb5/trunk@12044 dc483132-0cff-0310-8789-dd5450dbe970

diff --git a/src/lib/krb5/os/ChangeLog b/src/lib/krb5/os/ChangeLog
index 3833d682f30de836a57c7a35d823a14c59ed1175..598d169f6f49a364a6d0c56e3e1b5878b4eec3d9 100644 (file)
--- a/src/lib/krb5/os/ChangeLog
+++ b/src/lib/krb5/os/ChangeLog
@@ -1,3 +1,9 @@
+2000-02-16  Ken Raeburn  <raeburn@mit.edu>
+
+       * localaddr.c (krb5_os_localaddr): Dynamically grow buffer used
+       for SIOCGIFCONF until it appears to have been big enough.
+       Dynamically grow internal address pointer array as needed.
+
 2000-02-11  Marshall Vale  <mjv@mit.edu>
 
        * init_os_ctx.c (os_get_default_config_files.c): Added new

diff --git a/src/lib/krb5/os/localaddr.c b/src/lib/krb5/os/localaddr.c
index 96a25bf007225e755cc429f9ea9c72d6ecda49ba..e59bd38b5a5052ab14c403eb90becdadeeda1c82 100644 (file)
--- a/src/lib/krb5/os/localaddr.c
+++ b/src/lib/krb5/os/localaddr.c
@@ -115,28 +115,62 @@ krb5_os_localaddr(context, addr)
     struct ifreq *ifr, ifreq;
     struct ifconf ifc;
     int s, code, n, i;
-    char buf[1024*10];
-    krb5_address *addr_temp [ sizeof(buf)/sizeof(struct ifreq) ];
+    int est_if_count = 8, est_addr_count, est_ifreq_size;
+    char *buf = 0;
+    size_t current_buf_size = 0;
+    krb5_address **addr_temp = 0;
     int n_found;
     int mem_err = 0;
     
-    memset(buf, 0, sizeof(buf));
-    ifc.ifc_len = sizeof(buf);
-    ifc.ifc_buf = buf;
-
     s = socket (USE_AF, USE_TYPE, USE_PROTO);
     if (s < 0)
        return SOCKET_ERRNO;
 
+    /* At least on NetBSD, an ifreq can hold an IPv4 address, but
+       isn't big enough for an IPv6 or ethernet address.  So add a
+       little more space.  */
+    est_ifreq_size = sizeof (struct ifreq) + 8;
+    current_buf_size = est_ifreq_size * est_if_count;
+    buf = malloc (current_buf_size);
+
+ ask_again:
+    memset(buf, 0, current_buf_size);
+    ifc.ifc_len = current_buf_size;
+    ifc.ifc_buf = buf;
+
     code = ioctl (s, SIOCGIFCONF, (char *)&ifc);
     if (code < 0) {
        int retval = errno;
        closesocket (s);
        return retval;
     }
+    /* Test that the buffer was big enough that another ifreq could've
+       fit easily, if the OS wanted to provide one.  That seems to be
+       the only indication we get, complicated by the fact that the
+       associated address may make the required storage a little
+       bigger than the size of an ifreq.  */
+    if (current_buf_size - ifc.ifc_len < sizeof (struct ifreq) + 40) {
+       int new_size;
+       char *newbuf;
+
+       est_if_count *= 2;
+       new_size = est_ifreq_size * est_if_count;
+       newbuf = realloc (buf, new_size);
+       if (newbuf == 0) {
+           krb5_error_code e = errno;
+           free (buf);
+           return e;
+       }
+       current_buf_size = new_size;
+       buf = newbuf;
+       goto ask_again;
+    }
+
     n = ifc.ifc_len;
-    
-n_found = 0;
+    est_addr_count = (n + sizeof (struct ifreq) - 1) / sizeof (struct ifreq);
+    addr_temp = malloc (sizeof (krb5_address *) * est_addr_count);
+    n_found = 0;
+
     for (i = 0; i < n; i+= ifreq_size(*ifr) ) {
        krb5_address *address;
        ifr = (struct ifreq *)((caddr_t) ifc.ifc_buf+i);
@@ -161,7 +195,7 @@ n_found = 0;
            {
                struct sockaddr_in *in =
                    (struct sockaddr_in *)&ifr->ifr_addr;
-               
+
                address = (krb5_address *)
                    malloc (sizeof(krb5_address));
                if (address) {
@@ -247,11 +281,28 @@ n_found = 0;
        default:
            continue;
        }
-       if (address)
+       if (address) {
+           /* I doubt this will ever happen, since we were
+              conservative in figuring est_addr_count in the first
+              place...  */
+           if (n_found == est_addr_count - 1) {
+               krb5_address **nw;
+               est_addr_count *= 2;
+               nw = realloc (addr_temp,
+                             sizeof (krb5_address *) * est_addr_count);
+               if (nw == 0) {
+                   mem_err++;
+                   free (address);
+                   break;
+               }
+               addr_temp = nw;
+           }
            addr_temp[n_found++] = address;
+       }
        address = 0;
     }
     closesocket(s);
+    free (buf);
 
     *addr = (krb5_address **)malloc (sizeof (krb5_address *) * (n_found+1));
     if (*addr == 0)
@@ -262,6 +313,7 @@ n_found = 0;
            krb5_xfree(addr_temp[i]);
            addr_temp[i] = 0;
        }
+       free (addr_temp);
        return ENOMEM;
     }
     
@@ -269,6 +321,7 @@ n_found = 0;
        (*addr)[i] = addr_temp[i];
     }
     (*addr)[n_found] = 0;
+    free (addr_temp);
     return 0;
 }