svn commit: r347392 - head/sbin/ifconfig

[Kyle Evans]

Author: kevans
Date: Thu May  9 12:58:33 2019
New Revision: 347392
URL: https://svnweb.freebsd.org/changeset/base/347392

Log:
  ifconfig(8): Partial revert of r347241
  
  r347241 introduced an ifname <-> kld mapping table, mostly so tun/tap/vmnet
  can autoload the correct module on use. It also inadvertently made bogus
  some previously valid uses of sizeof().
  
  Revert back to ifkind on the stack for simplicity sake. This reduces the
  diff from the previous version of ifmaybeload for easiser auditing.

Modified:
  head/sbin/ifconfig/ifconfig.c

Modified: head/sbin/ifconfig/ifconfig.c
==============================================================================
--- head/sbin/ifconfig/ifconfig.c	Thu May  9 12:14:52 2019	(r347391)
+++ head/sbin/ifconfig/ifconfig.c	Thu May  9 12:58:33 2019	(r347392)
@@ -1433,7 +1433,7 @@ ifmaybeload(const char *name)
 #define MOD_PREFIX_LEN		3	/* "if_" */
 	struct module_stat mstat;
 	int i, fileid, modid;
-	char ifname[IFNAMSIZ], *ifkind, *dp;
+	char ifkind[IFNAMSIZ + MOD_PREFIX_LEN], ifname[IFNAMSIZ], *dp;
 	const char *cp;
 	struct module_map_entry *mme;
 
@@ -1450,21 +1450,17 @@ ifmaybeload(const char *name)
 		}
 
 	/* Either derive it from the map or guess otherwise */
-	ifkind = NULL;
+	*ifkind = '\0';
 	for (i = 0; i < nitems(module_map); ++i) {
 		mme = &module_map[i];
 		if (strcmp(mme->ifname, ifname) == 0) {
-			ifkind = strdup(mme->kldname);
-			if (ifkind == NULL)
-				err(EXIT_FAILURE, "ifmaybeload");
+			strlcpy(ifkind, mme->kldname, sizeof(ifkind));
 			break;
 		}
 	}
 
 	/* We didn't have an alias for it... we'll guess. */
-	if (ifkind == NULL) {
-	    ifkind = malloc(IFNAMSIZ + MOD_PREFIX_LEN);
-
+	if (*ifkind == '\0') {
 	    /* turn interface and unit into module name */
 	    strlcpy(ifkind, "if_", sizeof(ifkind));
 	    strlcat(ifkind, ifname, sizeof(ifkind));
@@ -1487,7 +1483,7 @@ ifmaybeload(const char *name)
 			/* already loaded? */
 			if (strcmp(ifname, cp) == 0 ||
 			    strcmp(ifkind, cp) == 0)
-				goto out;
+				return;
 		}
 	}
 
@@ -1496,8 +1492,6 @@ ifmaybeload(const char *name)
 	 * infer the names of all drivers (eg mlx4en(4)).
 	 */
 	(void) kldload(ifkind);
-out:
-	free(ifkind);
 }
 
 static struct cmd basic_cmds[] = {