X-Git-Url: https://git.librecmc.org/?a=blobdiff_plain;f=libbb%2Floop.c;h=823fba07952779d41d652b7762d6e96e6a44b7f0;hb=ac4100e103ca2b4e6e782c5814b1f43cef58c00b;hp=abf05dc4f0113f5dad372c2a75d6ac9a85c3158a;hpb=98f1dc12f1554aca6c3743bec1c3d8982a077f7c;p=oweals%2Fbusybox.git

diff --git a/libbb/loop.c b/libbb/loop.c
index abf05dc4f..823fba079 100644
--- a/libbb/loop.c
+++ b/libbb/loop.c
@@ -5,7 +5,7 @@
  * Copyright (C) 1999-2004 by Erik Andersen <andersen@codepoet.org>
  * Copyright (C) 2005 by Rob Landley <rob@landley.net>
  *
- * Licensed under the GPL v2 or later, see the file LICENSE in this tarball.
+ * Licensed under GPLv2 or later, see file LICENSE in this source tree.
  */
 #include "libbb.h"
 #include <linux/version.h>
@@ -56,7 +56,7 @@ char* FAST_FUNC query_loop(const char *device)
 	fd = open(device, O_RDONLY);
 	if (fd >= 0) {
 		if (ioctl(fd, BB_LOOP_GET_STATUS, &loopinfo) == 0) {
-			dev = xasprintf("%lu %s", (long) loopinfo.lo_offset,
+			dev = xasprintf("%"OFF_FMT"u %s", (off_t) loopinfo.lo_offset,
 					(char *)loopinfo.lo_file_name);
 		}
 		close(fd);
@@ -84,7 +84,7 @@ int FAST_FUNC del_loop(const char *device)
    search will re-use an existing loop device already bound to that
    file/offset if it finds one.
  */
-int FAST_FUNC set_loop(char **device, const char *file, unsigned long long offset)
+int FAST_FUNC set_loop(char **device, const char *file, unsigned long long offset, int ro)
 {
 	char dev[LOOP_NAMESIZE];
 	char *try;
@@ -93,25 +93,38 @@ int FAST_FUNC set_loop(char **device, const char *file, unsigned long long offse
 	int i, dfd, ffd, mode, rc = -1;
 
 	/* Open the file.  Barf if this doesn't work.  */
-	mode = O_RDWR;
+	mode = ro ? O_RDONLY : O_RDWR;
 	ffd = open(file, mode);
 	if (ffd < 0) {
-		mode = O_RDONLY;
-		ffd = open(file, mode);
+		if (mode != O_RDONLY) {
+			mode = O_RDONLY;
+			ffd = open(file, mode);
+		}
 		if (ffd < 0)
 			return -errno;
 	}
 
 	/* Find a loop device.  */
 	try = *device ? *device : dev;
-	for (i = 0; rc; i++) {
+	/* 1048575 is a max possible minor number in Linux circa 2010 */
+	for (i = 0; rc && i < 1048576; i++) {
 		sprintf(dev, LOOP_FORMAT, i);
 
-		/* Ran out of block devices, return failure.  */
+		IF_FEATURE_MOUNT_LOOP_CREATE(errno = 0;)
 		if (stat(try, &statbuf) != 0 || !S_ISBLK(statbuf.st_mode)) {
+			if (ENABLE_FEATURE_MOUNT_LOOP_CREATE
+			 && errno == ENOENT
+			 && try == dev
+			) {
+				/* Node doesn't exist, try to create it.  */
+				if (mknod(dev, S_IFBLK|0644, makedev(7, i)) == 0)
+					goto try_to_open;
+			}
+			/* Ran out of block devices, return failure.  */
 			rc = -ENOENT;
 			break;
 		}
+ try_to_open:
 		/* Open the sucker and check its loopiness.  */
 		dfd = open(try, mode);
 		if (dfd < 0 && errno == EROFS) {
@@ -137,9 +150,9 @@ int FAST_FUNC set_loop(char **device, const char *file, unsigned long long offse
 			}
 
 		/* If this block device already set up right, re-use it.
-		   (Yes this is racy, but associating two loop devices with the same
-		   file isn't pretty either.  In general, mounting the same file twice
-		   without using losetup manually is problematic.)
+		 * (Yes this is racy, but associating two loop devices with the same
+		 * file isn't pretty either.  In general, mounting the same file twice
+		 * without using losetup manually is problematic.)
 		 */
 		} else
 		if (strcmp(file, (char *)loopinfo.lo_file_name) != 0