Add gcc-fortify-source branch

.topdeps

@@ -0,0 +1 @@
+master

.topmsg

@@ -0,0 +1,14 @@
+From: Brian Behlendorf <behlendorf1@llnl.gov>
+Subject: [PATCH] gcc fortify source
+
+Resolve issues uncovered by -D_FORTIFY_SOURCE=2, the default redhat
+macro's file adds this option to the cflags.  This causes warnings
+of the following type designed to keep the developer honest:
+
+        warning: ignoring return value of 'foo', declared
+                 with attribute warn_unused_result
+
+The short term fix is to wrap these calls in VERIFY() to check the
+return code.  The code was already assusing these would never fail.
+
+Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>

cmd/zdb/zdb.c

@@ -1875,7 +1875,7 @@ zdb_dump_block_raw(void *buf, uint64_t size, int flags)
 {
 	if (flags & ZDB_FLAG_BSWAP)
 		byteswap_uint64_array(buf, size);
-	(void) write(2, buf, size);
+	VERIFY(write(fileno(stderr), buf, size) == size);
 }
 
 static void

cmd/ztest/ztest.c

@@ -1170,7 +1170,7 @@ ztest_vdev_LUN_growth(ztest_args_t *za)
 		 */
 		if (fsize < 2 * zopt_vdev_size) {
 			size_t newsize = fsize + ztest_random(fsize / 32);
-			(void) ftruncate(fd, newsize);
+			VERIFY(ftruncate(fd, newsize) == 0);
 			if (zopt_verbose >= 6) {
 				(void) printf("%s grew from %lu to %lu bytes\n",
 				    dev_name, (ulong_t)fsize, (ulong_t)newsize);

lib/libzpool/kernel.c

@@ -764,7 +764,7 @@ umem_out_of_memory(void)
 {
 	char errmsg[] = "out of memory -- generating core dump\n";
 
-	write(fileno(stderr), errmsg, sizeof (errmsg));
+	(void) fprintf(stderr, "%s", errmsg);
 	abort();
 	return (0);
 }