tar: support -T - and -X -

[oweals/busybox.git] / libbb / loop.c

diff --git a/libbb/loop.c b/libbb/loop.c
index 24dab1ac0533b79a95bdddd69850bdbcc8289bfc..b798932faf66aa0e68a8bb4095f9daf74dc26b2b 100644 (file)
--- 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>
@@ -13,13 +13,8 @@
 #if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,0)
 
 /* For 2.6, use the cleaned up header to get the 64 bit API. */
-/* linux/loop.h relies on __u64. Make sure we have that as a proper type
- * until userspace is widely fixed. */
-# if (defined __INTEL_COMPILER && !defined __GNUC__) \
-  || (defined __GNUC__ && defined __STRICT_ANSI__)
-__extension__ typedef long long __s64;
-__extension__ typedef unsigned long long __u64;
-# endif
+// Commented out per Rob's request
+//# include "fix_u32.h" /* some old toolchains need __u64 for linux/loop.h */
 # include <linux/loop.h>
 typedef struct loop_info64 bb_loop_info;
 # define BB_LOOP_SET_STATUS LOOP_SET_STATUS64
@@ -56,14 +51,16 @@ char* FAST_FUNC query_loop(const char *device)
 {
        int fd;
        bb_loop_info loopinfo;
-       char *dev = 0;
+       char *dev = NULL;
 
        fd = open(device, O_RDONLY);
-       if (fd < 0) return 0;
-       if (!ioctl(fd, BB_LOOP_GET_STATUS, &loopinfo))
-               dev = xasprintf("%ld %s", (long) loopinfo.lo_offset,
-                               (char *)loopinfo.lo_file_name);
-       close(fd);
+       if (fd >= 0) {
+               if (ioctl(fd, BB_LOOP_GET_STATUS, &loopinfo) == 0) {
+                       dev = xasprintf("%"OFF_FMT"u %s", (off_t) loopinfo.lo_offset,
+                                       (char *)loopinfo.lo_file_name);
+               }
+               close(fd);
+       }
 
        return dev;
 }
@@ -73,7 +70,8 @@ int FAST_FUNC del_loop(const char *device)
        int fd, rc;
 
        fd = open(device, O_RDONLY);
-       if (fd < 0) return 1;
+       if (fd < 0)
+               return 1;
        rc = ioctl(fd, LOOP_CLR_FD, 0);
        close(fd);
 
@@ -105,15 +103,26 @@ int FAST_FUNC set_loop(char **device, const char *file, unsigned long long offse
        }
 
        /* Find a loop device.  */
-       try = *device ? : dev;
-       for (i = 0; rc; i++) {
+       try = *device ? *device : dev;
+       /* 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 (stat(try, &statbuf) || !S_ISBLK(statbuf.st_mode)) {
+               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) {
@@ -131,8 +140,8 @@ int FAST_FUNC set_loop(char **device, const char *file, unsigned long long offse
                        safe_strncpy((char *)loopinfo.lo_file_name, file, LO_NAME_SIZE);
                        loopinfo.lo_offset = offset;
                        /* Associate free loop device with file.  */
-                       if (!ioctl(dfd, LOOP_SET_FD, ffd)) {
-                               if (!ioctl(dfd, BB_LOOP_SET_STATUS, &loopinfo))
+                       if (ioctl(dfd, LOOP_SET_FD, ffd) == 0) {
+                               if (ioctl(dfd, BB_LOOP_SET_STATUS, &loopinfo) == 0)
                                        rc = 0;
                                else
                                        ioctl(dfd, LOOP_CLR_FD, 0);
@@ -143,8 +152,10 @@ int FAST_FUNC set_loop(char **device, const char *file, unsigned long long offse
                   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
-               || offset != loopinfo.lo_offset) {
+               } else
+               if (strcmp(file, (char *)loopinfo.lo_file_name) != 0
+                || offset != loopinfo.lo_offset
+               ) {
                        rc = -1;
                }
                close(dfd);
@@ -152,7 +163,7 @@ int FAST_FUNC set_loop(char **device, const char *file, unsigned long long offse
                if (*device) break;
        }
        close(ffd);
-       if (!rc) {
+       if (rc == 0) {
                if (!*device)
                        *device = xstrdup(dev);
                return (mode == O_RDONLY); /* 1:ro, 0:rw */