PERFORCE change 101079 for review

[Scott Long]

http://perforce.freebsd.org/chv.cgi?CH=101079

Change 101079 by scottl at scottl-wv1u on 2006/07/09 07:59:10

	Short-circuit the temp buffer if kenv(KENV_DUMP) is called with a
	length of 0 or a NULL buffer.  ALso remove a redundant check.

Affected files ...

.. //depot/projects/scottl-camlock/src/sys/kern/kern_environment.c#8 edit

Differences ...

==== //depot/projects/scottl-camlock/src/sys/kern/kern_environment.c#8 (text+ko) ====

@@ -85,7 +85,7 @@
 		int len;
 	} */ *uap;
 {
-	char *name, *value, *buffer;
+	char *name, *value, *buffer = NULL;
 	size_t len, done, needed;
 	int error, i;
 
@@ -99,7 +99,8 @@
 			return (error);
 #endif
 		done = needed = 0;
-		buffer = malloc(uap->len, M_TEMP, M_WAITOK|M_ZERO);
+		if (uap->len > 0 && uap->value != NULL)
+			buffer = malloc(uap->len, M_TEMP, M_WAITOK|M_ZERO);
 		mtx_lock(&kenv_lock);
 		for (i = 0; kenvp[i] != NULL; i++) {
 			len = strlen(kenvp[i]) + 1;
@@ -109,16 +110,16 @@
 			 * If called with a NULL or insufficiently large
 			 * buffer, just keep computing the required size.
 			 */
-			if (uap->value != NULL && len > 0) {
-				if (done + len > uap->len)
-					break;
+			if (uap->value != NULL && buffer != NULL && len > 0) {
 				bcopy(kenvp[i], buffer + done, len);
 				done += len;
 			}
 		}
 		mtx_unlock(&kenv_lock);
-		error = copyout(buffer, uap->value, done);
-		free(buffer, M_TEMP);
+		if (buffer != NULL) {
+			error = copyout(buffer, uap->value, done);
+			free(buffer, M_TEMP);
+		}
 		td->td_retval[0] = ((done == needed) ? 0 : needed);
 		return (error);
 	}