* Utility routines.
*
* Copyright (C) 1999-2004 by Erik Andersen <andersen@codepoet.org>
+ * Copyright (C) 2005 by Rob Landley <rob@landley.net>
*
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation; either version 2 of the License, or
- * (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
- * General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program; if not, write to the Free Software
- * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ * Licensed under GPLv2 or later, see file LICENSE in this source tree.
*/
-
-#include <features.h>
-#if defined (__GLIBC__) && !defined(__UCLIBC__)
-#include <linux/posix_types.h>
-#endif
-#include <stdio.h>
-#include <errno.h>
-#include <fcntl.h>
-#include <string.h>
-#include <unistd.h>
-#include <sys/ioctl.h>
#include "libbb.h"
-#ifdef CONFIG_FEATURE_MOUNT_LOOP
-
-/* Grumble... The 2.6.x kernel breaks asm/posix_types.h
- * so we get to try and cope as best we can... */
#include <linux/version.h>
#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,0)
-#define __bb_kernel_dev_t __kernel_old_dev_t
-#elif LINUX_VERSION_CODE < KERNEL_VERSION(2,6,0)
-#define __bb_kernel_dev_t __kernel_dev_t
+
+/* 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
+
#else
-#define __bb_kernel_dev_t unsigned short
-#endif
-/* Stuff stolen from linux/loop.h */
-#define LO_NAME_SIZE 64
-#define LO_KEY_SIZE 32
-#define LOOP_SET_FD 0x4C00
-#define LOOP_CLR_FD 0x4C01
-#define LOOP_SET_STATUS 0x4C02
-#define LOOP_GET_STATUS 0x4C03
-struct loop_info {
+/* 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;
- __bb_kernel_dev_t lo_device;
+ __kernel_dev_t lo_device;
unsigned long lo_inode;
- __bb_kernel_dev_t lo_rdevice;
+ __kernel_dev_t lo_rdevice;
int lo_offset;
int lo_encrypt_type;
int lo_encrypt_key_size;
int lo_flags;
- char lo_name[LO_NAME_SIZE];
+ char lo_file_name[LO_NAME_SIZE];
unsigned char lo_encrypt_key[LO_KEY_SIZE];
unsigned long lo_init[2];
char reserved[4];
-};
+} bb_loop_info;
+#endif
-extern int del_loop(const char *device)
+char* FAST_FUNC query_loop(const char *device)
{
int fd;
+ bb_loop_info loopinfo;
+ char *dev = NULL;
- if ((fd = open(device, O_RDONLY)) < 0) {
- bb_perror_msg("%s", device);
- return (FALSE);
- }
- if (ioctl(fd, LOOP_CLR_FD, 0) < 0) {
+ 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);
- bb_perror_msg("ioctl: LOOP_CLR_FD");
- return (FALSE);
}
- close(fd);
- return (TRUE);
+
+ return dev;
}
-extern int set_loop(const char *device, const char *file, int offset,
- int *loopro)
+int FAST_FUNC del_loop(const char *device)
{
- struct loop_info loopinfo;
- int fd, ffd, mode;
+ int fd, rc;
- mode = *loopro ? O_RDONLY : O_RDWR;
- if ((ffd = open(file, mode)) < 0 && !*loopro
- && (errno != EROFS || (ffd = open(file, mode = O_RDONLY)) < 0)) {
- bb_perror_msg("%s", file);
+ fd = open(device, O_RDONLY);
+ if (fd < 0)
return 1;
- }
- if ((fd = open(device, mode)) < 0) {
- close(ffd);
- bb_perror_msg("%s", device);
- return 1;
- }
- *loopro = (mode == O_RDONLY);
+ rc = ioctl(fd, LOOP_CLR_FD, 0);
+ close(fd);
- memset(&loopinfo, 0, sizeof(loopinfo));
- safe_strncpy(loopinfo.lo_name, file, LO_NAME_SIZE);
+ return rc;
+}
- loopinfo.lo_offset = offset;
+/* Obtain an unused loop device number */
+int FAST_FUNC get_free_loop(void)
+{
+ int fd;
+ int loopdevno;
- loopinfo.lo_encrypt_key_size = 0;
- if (ioctl(fd, LOOP_SET_FD, ffd) < 0) {
- bb_perror_msg("ioctl: LOOP_SET_FD");
- close(fd);
- close(ffd);
- return 1;
- }
- if (ioctl(fd, LOOP_SET_STATUS, &loopinfo) < 0) {
- (void) ioctl(fd, LOOP_CLR_FD, 0);
- bb_perror_msg("ioctl: LOOP_SET_STATUS");
- close(fd);
- close(ffd);
- return 1;
- }
+ fd = open("/dev/loop-control", O_RDWR | O_CLOEXEC);
+ if (fd == -1)
+ return fd - 1; /* -2: "no /dev/loop-control" */
+
+#ifndef LOOP_CTL_GET_FREE
+# define LOOP_CTL_GET_FREE 0x4C82
+#endif
+ loopdevno = ioctl(fd, LOOP_CTL_GET_FREE);
close(fd);
- close(ffd);
- return 0;
+ return loopdevno; /* can be -1 if error */
}
-extern char *find_unused_loop_device(void)
+/* 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 FAST_FUNC set_loop(char **device, const char *file, unsigned long long offset, unsigned flags)
{
- char dev[20];
- int i, fd;
+ char dev[LOOP_NAMESIZE];
+ char *try;
+ bb_loop_info loopinfo;
struct stat statbuf;
- struct loop_info loopinfo;
+ int i, dfd, ffd, mode, rc;
+
+ rc = dfd = -1;
+
+ /* Open the file. Barf if this doesn't work. */
+ 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;
+ }
- for (i = 0; i <= CONFIG_FEATURE_MOUNT_LOOP_MAX; i++) {
+ try = *device;
+ if (!try) {
+ i = get_free_loop();
+ if (i == -2) { /* no /dev/loop-control */
+ i = 0;
+ try = dev;
+ goto old_style;
+ }
+ if (i == -1) {
+ close(ffd);
+ return -1; /* no free loop devices */
+ }
+ try = *device = xasprintf(LOOP_FORMAT, i);
+ goto try_to_open;
+ }
+
+ old_style:
+ /* Find a loop device. */
+ /* 1048575 (0xfffff) is a max possible minor number in Linux circa 2010 */
+ for (i = 0; rc && i < 1048576; i++) {
sprintf(dev, LOOP_FORMAT, i);
- if (stat(dev, &statbuf) == 0 && S_ISBLK(statbuf.st_mode)) {
- if ((fd = open(dev, O_RDONLY)) >= 0) {
- if (ioctl(fd, LOOP_GET_STATUS, &loopinfo) != 0) {
- if (errno == ENXIO) { /* probably free */
- close(fd);
- return strdup(dev);
- }
+
+ 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. */
+ 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);
+
+ /* If device is free, claim it. */
+ if (rc && errno == ENXIO) {
+ /* Associate free loop device with file. */
+ 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); // actually, 0 param is unnecessary
}
- close(fd);
}
+ } else {
+ rc = -1;
+ }
+ if (rc != 0) {
+ close(dfd);
}
+ try_again:
+ if (*device) break;
}
- return NULL;
+ close(ffd);
+ if (rc == 0) {
+ if (!*device)
+ *device = xstrdup(dev);
+ return dfd;
+ }
+ return rc;
}
-#endif
-
-
-/* END CODE */
-/*
-Local Variables:
-c-file-style: "linux"
-c-basic-offset: 4
-tab-width: 4
-End:
-*/
projects / oweals / busybox.git / blobdiff