* Utility routines.
*
* 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 <features.h>
-#include <stdio.h>
-#include <errno.h>
-#include <fcntl.h>
-#include <string.h>
-#include <unistd.h>
-#include <sys/ioctl.h>
#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;
- if ((fd = open(device, O_RDONLY)) < 0) return 0;
- if (!ioctl(fd, BB_LOOP_GET_STATUS, &loopinfo))
- dev=bb_xasprintf("%ld %s", (long) loopinfo.lo_offset,
- (char *)loopinfo.lo_file_name);
- close(fd);
+ fd = open(device, O_RDONLY);
+ 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;
- if ((fd = open(device, O_RDONLY)) < 0) return 1;
- rc=ioctl(fd, LOOP_CLR_FD, 0);
+ fd = open(device, O_RDONLY);
+ if (fd < 0)
+ return 1;
+ rc = ioctl(fd, LOOP_CLR_FD, 0);
close(fd);
return rc;
}
-/* Returns 0 if mounted RW, 1 if mounted read-only, <0 for error.
- *device is loop device to use, or if *device==NULL finds a loop device to
- mount it on and sets *device to a strdup of that loop device name. This
- search will re-use an existing loop device already bound to that
- file/offset if it finds one.
+/* Returns opened fd to the loop device, <0 on error.
+ * *device is loop device to use, or if *device==NULL finds a loop device to
+ * mount it on and sets *device to a strdup of that loop device name. This
+ * 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, int offset)
+int FAST_FUNC set_loop(char **device, const char *file, unsigned long long offset, unsigned flags)
{
- 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;
+
+ rc = dfd = -1;
+
/* Open the file. Barf if this doesn't work. */
- if((ffd = open(file, mode=O_RDWR))<0 && (ffd = open(file,mode=O_RDONLY))<0)
+ mode = (flags & BB_LO_FLAGS_READ_ONLY) ? O_RDONLY : O_RDWR;
+ open_ffd:
+ ffd = open(file, mode);
+ if (ffd < 0) {
+ if (mode != O_RDONLY) {
+ mode = O_RDONLY;
+ goto open_ffd;
+ }
return -errno;
+ }
/* Find a loop device. */
- try=*device ? : dev;
- for(i=0;rc;i++) {
+ try = *device ? *device : dev;
+ /* 1048575 (0xfffff) 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 = -1;
break;
}
+ try_to_open:
/* Open the sucker and check its loopiness. */
- if((dfd=open(try, mode))<0 && errno==EROFS)
- dfd=open(try, mode = O_RDONLY);
- if(dfd<0) goto try_again;
+ dfd = open(try, mode);
+ if (dfd < 0 && errno == EROFS) {
+ mode = O_RDONLY;
+ dfd = open(try, mode);
+ }
+ if (dfd < 0) {
+ if (errno == ENXIO) {
+ /* Happens if loop module is not loaded */
+ rc = -1;
+ break;
+ }
+ goto try_again;
+ }
- rc=ioctl(dfd, BB_LOOP_GET_STATUS, &loopinfo);
+ rc = ioctl(dfd, BB_LOOP_GET_STATUS, &loopinfo);
- /* If device 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;
+ /* If device is free, claim it. */
+ if (rc && errno == ENXIO) {
/* 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) {
+ memset(&loopinfo, 0, sizeof(loopinfo));
+ safe_strncpy((char *)loopinfo.lo_file_name, file, LO_NAME_SIZE);
+ loopinfo.lo_offset = offset;
+ /*
+ * Used by mount to set LO_FLAGS_AUTOCLEAR.
+ * LO_FLAGS_READ_ONLY is not set because RO is controlled by open type of the file.
+ * Note that closing LO_FLAGS_AUTOCLEARed dfd before mount
+ * is wrong (would free the loop device!)
+ */
+ loopinfo.lo_flags = (flags & ~BB_LO_FLAGS_READ_ONLY);
+ rc = ioctl(dfd, BB_LOOP_SET_STATUS, &loopinfo);
+ if (rc != 0 && (loopinfo.lo_flags & BB_LO_FLAGS_AUTOCLEAR)) {
+ /* Old kernel, does not support LO_FLAGS_AUTOCLEAR? */
+ /* (this code path is not tested) */
+ loopinfo.lo_flags -= BB_LO_FLAGS_AUTOCLEAR;
+ rc = ioctl(dfd, BB_LOOP_SET_STATUS, &loopinfo);
+ }
+ if (rc != 0) {
+ 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.)
- */
- } else if(strcmp(file,(char *)loopinfo.lo_file_name)
- || offset!=loopinfo.lo_offset) rc=-1;
- close(dfd);
-try_again:
- if(*device) break;
+ } else {
+ rc = -1;
+ }
+ if (rc != 0) {
+ close(dfd);
+ }
+ try_again:
+ if (*device) break;
}
close(ffd);
- if(!rc) {
- if(!*device) *device=strdup(dev);
- return mode==O_RDONLY ? 1 : 0;
- } else return rc;
+ if (rc == 0) {
+ if (!*device)
+ *device = xstrdup(dev);
+ return dfd;
+ }
+ return rc;
}
projects / oweals / busybox.git / blobdiff