diff -rupN xen-unstable.hg-3.0.5-pre-14797.orig/tools/blktap/drivers/blktapctrl.c xen-unstable.hg-3.0.5-pre-14797.new/tools/blktap/drivers/blktapctrl.c
--- xen-unstable.hg-3.0.5-pre-14797.orig/tools/blktap/drivers/blktapctrl.c	2007-04-11 19:10:30.000000000 -0400
+++ xen-unstable.hg-3.0.5-pre-14797.new/tools/blktap/drivers/blktapctrl.c	2007-04-13 11:32:14.000000000 -0400
@@ -673,7 +673,10 @@ int main(int argc, char *argv[])
 	__init_blkif();
 	snprintf(buf, sizeof(buf), "BLKTAPCTRL[%d]", getpid());
 	openlog(buf, LOG_CONS|LOG_ODELAY, LOG_DAEMON);
-	daemon(0,0);
+	if (daemon(0,0) < 0) {
+		DPRINTF("could not go into daemon mode\n");
+		return -1;
+	}
 
 	print_drivers();
 	init_driver_list();
diff -rupN xen-unstable.hg-3.0.5-pre-14797.orig/tools/blktap/drivers/block-aio.c xen-unstable.hg-3.0.5-pre-14797.new/tools/blktap/drivers/block-aio.c
--- xen-unstable.hg-3.0.5-pre-14797.orig/tools/blktap/drivers/block-aio.c	2007-04-13 11:32:01.000000000 -0400
+++ xen-unstable.hg-3.0.5-pre-14797.new/tools/blktap/drivers/block-aio.c	2007-04-13 11:33:22.000000000 -0400
@@ -203,13 +203,27 @@ int tdaio_open (struct disk_driver *dd, 
 
         prv->fd = fd;
 
-	pipe(prv->command_fd);
-	pipe(prv->completion_fd);
-
-	ret = pthread_create(&prv->aio_thread, NULL,
-			     tdaio_completion_thread, prv);
-	ret = 0;
-	write(prv->command_fd[1], &ret, sizeof(ret));
+ 	if ((ret = pipe(prv->command_fd)) < 0) {
+ 		DPRINTF("Unable to create command pipe\n");
+ 		goto done;
+ 	}
+ 	if ((ret = pipe(prv->completion_fd)) < 0) {
+ 		DPRINTF("Unable to create completion pipe\n");
+ 		goto done;
+ 	}
+ 	
+ 	if ((ret = pthread_create(&prv->aio_thread, NULL, 
+ 				  tdaio_completion_thread, prv)) != 0) {
+ 		ret = -1;
+ 		DPRINTF("Unable to create completion thread\n");
+ 		goto done;
+ 	}
+  	ret = 0;
+ 	if (write(prv->command_fd[1], &ret, sizeof(ret)) < 0) {
+ 		ret = -1;
+ 		DPRINTF("Cannot initialize command pipe\n");
+ 		goto done;
+ 	}
 
 	init_fds(dd);
 	ret = get_image_info(s, fd);
@@ -382,7 +396,10 @@ repeat:
 		goto repeat;
 	}
 
-	write(prv->command_fd[1], &nr_events, sizeof(nr_events));
+	if (write(prv->command_fd[1], &nr_events, sizeof(nr_events)) < 0) {
+		DPRINTF("cannot send events command\n");
+		return -1;
+	}
 
 	return rsp;
 }
diff -rupN xen-unstable.hg-3.0.5-pre-14797.orig/tools/blktap/drivers/block-qcow.c xen-unstable.hg-3.0.5-pre-14797.new/tools/blktap/drivers/block-qcow.c
--- xen-unstable.hg-3.0.5-pre-14797.orig/tools/blktap/drivers/block-qcow.c	2007-04-11 19:10:30.000000000 -0400
+++ xen-unstable.hg-3.0.5-pre-14797.new/tools/blktap/drivers/block-qcow.c	2007-04-13 11:36:55.000000000 -0400
@@ -707,7 +707,10 @@ found:
 		}
 		memcpy(tmp_ptr2, l2_ptr, 4096);
 		lseek(s->fd, l2_offset + (l2_sector << 12), SEEK_SET);
-		write(s->fd, tmp_ptr2, 4096);
+		if (write(s->fd, tmp_ptr2, 4096) < 0) {
+			free(tmp_ptr2);
+			return -1;
+		}
 		free(tmp_ptr2);
 	}
 	return cluster_offset;
@@ -1112,20 +1115,26 @@ int tdqcow_close(struct disk_driver *dd)
 {
 	struct tdqcow_state *s = (struct tdqcow_state *)dd->private;
 	uint32_t cksum, out;
-	int fd, offset;
+	int fd, offset, ret = 0;
 
 	/*Update the hdr cksum*/
 	if(s->min_cluster_alloc == s->l2_size) {
 		cksum = gen_cksum((char *)s->l1_table, s->l1_size * sizeof(uint64_t));
 		printf("Writing cksum: %d",cksum);
-		fd = open(s->name, O_WRONLY | O_LARGEFILE); /*Open without O_DIRECT*/
+ 		if ((fd = open(s->name, O_WRONLY | O_LARGEFILE)) < 0) { /*Open without O_DIRECT*/
+ 			ret = -1;
+ 			goto cleanup;
+ 		}
 		offset = sizeof(QCowHeader) + sizeof(uint32_t);
 		lseek(fd, offset, SEEK_SET);
 		out = cpu_to_be32(cksum);
-		write(fd, &out, sizeof(uint32_t));
+ 		if ((ret = write(fd, &out, sizeof(uint32_t))) < 0) {
+ 			ret = -1;
+ 		}
 		close(fd);
 	}
 
+  cleanup:
 	io_destroy(s->aio_ctx);
 	free(s->name);
 	free(s->l1_table);
@@ -1212,7 +1221,9 @@ int qcow_create(const char *filename, ui
 				strncpy(backing_filename, backing_file,
 					sizeof(backing_filename));
 			} else {
-				realpath(backing_file, backing_filename);
+			  	if (!realpath(backing_file, backing_filename)) {
+					return -1;
+				}
 				if (stat(backing_filename, &st) != 0) {
 					return -1;
 				}
diff -rupN xen-unstable.hg-3.0.5-pre-14797.orig/tools/blktap/drivers/block-vmdk.c xen-unstable.hg-3.0.5-pre-14797.new/tools/blktap/drivers/block-vmdk.c
--- xen-unstable.hg-3.0.5-pre-14797.orig/tools/blktap/drivers/block-vmdk.c	2007-04-11 19:10:30.000000000 -0400
+++ xen-unstable.hg-3.0.5-pre-14797.new/tools/blktap/drivers/block-vmdk.c	2007-04-13 11:32:14.000000000 -0400
@@ -283,8 +283,10 @@ static uint64_t get_cluster_offset(struc
         	if (!allocate)
             		return 0;
         	cluster_offset = lseek(prv->fd, 0, SEEK_END);
-        	ftruncate(prv->fd, cluster_offset + 
-			  (prv->cluster_sectors << 9));
+        	if (ftruncate(prv->fd, cluster_offset + 
+			      (prv->cluster_sectors << 9)) < 0) {
+			return 0;
+		}
         	cluster_offset >>= 9;
         	/* update L2 table */
         	tmp = cpu_to_le32(cluster_offset);