* 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"
-
-/* For 2.6, use the cleaned up header to get the 64 bit API. */
#include <linux/version.h>
+
#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,0)
-#include <linux/loop.h>
+
+/* For 2.6, use the cleaned up header to get the 64 bit API. */
+// 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
-#define BB_LOOP_GET_STATUS LOOP_GET_STATUS64
+# define BB_LOOP_SET_STATUS LOOP_SET_STATUS64
+# define BB_LOOP_GET_STATUS LOOP_GET_STATUS64
-/* For 2.4 and earlier, use the 32 bit API (and don't trust the headers) */
#else
-/* Stuff stolen from linux/loop.h for 2.4 and earlier kernels*/
-#include <linux/posix_types.h>
-#define LO_NAME_SIZE 64
-#define LO_KEY_SIZE 32
-#define LOOP_SET_FD 0x4C00
-#define LOOP_CLR_FD 0x4C01
-#define BB_LOOP_SET_STATUS 0x4C02
-#define BB_LOOP_GET_STATUS 0x4C03
+
+/* For 2.4 and earlier, use the 32 bit API (and don't trust the headers) */
+/* Stuff stolen from linux/loop.h for 2.4 and earlier kernels */
+# include <linux/posix_types.h>
+# define LO_NAME_SIZE 64
+# define LO_KEY_SIZE 32
+# define LOOP_SET_FD 0x4C00
+# define LOOP_CLR_FD 0x4C01
+# define BB_LOOP_SET_STATUS 0x4C02
+# define BB_LOOP_GET_STATUS 0x4C03
typedef struct {
int lo_number;
__kernel_dev_t lo_device;
} bb_loop_info;
#endif
-char *query_loop(const char *device)
+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;
}
-
-int del_loop(const char *device)
+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);
search will re-use an existing loop device already bound to that
file/offset if it finds one.
*/
-int 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[20], *try;
+ char dev[LOOP_NAMESIZE];
+ char *try;
bb_loop_info loopinfo;
struct stat statbuf;
- int i, dfd, ffd, mode, rc=-1;
+ 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 ? : 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)) {
- rc=-ENOENT;
+ 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) {
mode = O_RDONLY;
dfd = open(try, mode);
}
- if (dfd < 0) goto try_again;
+ if (dfd < 0)
+ goto try_again;
rc = ioctl(dfd, BB_LOOP_GET_STATUS, &loopinfo);
- /* If device free, claim it. */
+ /* If device is free, claim it. */
if (rc && errno == ENXIO) {
memset(&loopinfo, 0, sizeof(loopinfo));
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)) rc = 0;
- else ioctl(dfd, LOOP_CLR_FD, 0);
+ 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);
}
/* 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)
- || offset != loopinfo.lo_offset) {
+ } else
+ if (strcmp(file, (char *)loopinfo.lo_file_name) != 0
+ || offset != loopinfo.lo_offset
+ ) {
rc = -1;
}
close(dfd);
-try_again:
+ try_again:
if (*device) break;
}
close(ffd);
- if (!rc) {
- if (!*device) *device = strdup(dev);
- return mode==O_RDONLY ? 1 : 0;
+ if (rc == 0) {
+ if (!*device)
+ *device = xstrdup(dev);
+ return (mode == O_RDONLY); /* 1:ro, 0:rw */
}
return rc;
}