Vendor fix: the routing table can change while we are fetching it from

the kernel. Instead of complaining if we get an ENOMEM (meaning it got
larger than our buffer is) reallocate the buffer and loop.

Submitted by: maxim

1 files changed, 19 insertions, 9 deletions

diff --git a/contrib/bsnmp/snmp_mibII/mibII.c b/contrib/bsnmp/snmp_mibII/mibII.c
index 2f7881f..aa5cb83 100644
--- a/contrib/bsnmp/snmp_mibII/mibII.c
+++ b/contrib/bsnmp/snmp_mibII/mibII.c
@@ -1030,7 +1030,7 @@ u_char *
 mib_fetch_rtab(int af, int info, int arg, size_t *lenp)
 {
 	int name[6];
-	u_char *buf;
+	u_char *buf, *newbuf;
 
 	name[0] = CTL_NET;
 	name[1] = PF_ROUTE;
@@ -1041,6 +1041,7 @@ mib_fetch_rtab(int af, int info, int arg, size_t *lenp)
 
 	*lenp = 0;
 
+	/* initial estimate */
 	if (sysctl(name, 6, NULL, lenp, NULL, 0) == -1) {
 		syslog(LOG_ERR, "sysctl estimate (%d,%d,%d,%d,%d,%d): %m",
 		    name[0], name[1], name[2], name[3], name[4], name[5]);
@@ -1049,15 +1050,24 @@ mib_fetch_rtab(int af, int info, int arg, size_t *lenp)
 	if (*lenp == 0)
 		return (NULL);
 
-	if ((buf = malloc(*lenp)) == NULL) {
-		syslog(LOG_ERR, "sysctl buffer: %m");
-		return (NULL);
-	}
+	buf = NULL;
+	for (;;) {
+		if ((newbuf = realloc(buf, *lenp)) == NULL) {
+			syslog(LOG_ERR, "sysctl buffer: %m");
+			free(buf);
+			return (NULL);
+		}
+		buf = newbuf;
+			
+		if (sysctl(name, 6, buf, lenp, NULL, 0) == 0)
+			break;
 
-	if (sysctl(name, 6, buf, lenp, NULL, 0) == -1) {
-		syslog(LOG_ERR, "sysctl get: %m");
-		free(buf);
-		return (NULL);
+		if (errno != ENOMEM) {
+			syslog(LOG_ERR, "sysctl get: %m");
+			free(buf);
+			return (NULL);
+		}
+		*lenp += *lenp / 8 + 1;
 	}
 
 	return (buf);