diff options
Diffstat (limited to 'libblkid/loopdev.c')
| -rw-r--r-- | libblkid/loopdev.c | 1559 |
1 files changed, 0 insertions, 1559 deletions
diff --git a/libblkid/loopdev.c b/libblkid/loopdev.c deleted file mode 100644 index a25a2fae4..000000000 --- a/libblkid/loopdev.c +++ /dev/null @@ -1,1559 +0,0 @@ -/* - * No copyright is claimed. This code is in the public domain; do with - * it what you wish. - * - * Written by Karel Zak <kzak@redhat.com> - * - * -- based on mount/losetup.c - * - * Simple library for work with loop devices. - * - * - requires kernel 2.6.x - * - reads info from /sys/block/loop<N>/loop/<attr> (new kernels) - * - reads info by ioctl - * - supports *unlimited* number of loop devices - * - supports /dev/loop<N> as well as /dev/loop/<N> - * - minimize overhead (fd, loopinfo, ... are shared for all operations) - * - setup (associate device and backing file) - * - delete (dis-associate file) - * - old LOOP_{SET,GET}_STATUS (32bit) ioctls are unsupported - * - extendible - */ -#include <stdio.h> -#include <stdint.h> -#include <string.h> -#include <ctype.h> -#include <fcntl.h> -#include <stdlib.h> -#include <unistd.h> -#include <sys/ioctl.h> -#include <sys/stat.h> -#include <sys/mman.h> -#include <sys/sysmacros.h> -#include <inttypes.h> -#include <dirent.h> -#include <linux/posix_types.h> - -#include "linux_version.h" -#include "c.h" -#include "sysfs.h" -#include "pathnames.h" -#include "loopdev.h" -#include "canonicalize.h" -#include "at.h" - -#define CONFIG_LOOPDEV_DEBUG - -#ifdef CONFIG_LOOPDEV_DEBUG -# include <stdarg.h> - -# define DBG(l,x) do { \ - if ((l)->debug) {\ - fprintf(stderr, "loopdev: [%p]: ", (l)); \ - x; \ - } \ - } while(0) - -static inline void __attribute__ ((__format__ (__printf__, 1, 2))) -loopdev_debug(const char *mesg, ...) -{ - va_list ap; - va_start(ap, mesg); - vfprintf(stderr, mesg, ap); - va_end(ap); - fputc('\n', stderr); -} - -#else /* !CONFIG_LOOPDEV_DEBUG */ -# define DBG(m,x) do { ; } while(0) -#endif - -/* - * see loopcxt_init() - */ -#define loopcxt_ioctl_enabled(_lc) (!((_lc)->flags & LOOPDEV_FL_NOIOCTL)) -#define loopcxt_sysfs_available(_lc) (!((_lc)->flags & LOOPDEV_FL_NOSYSFS)) \ - && !loopcxt_ioctl_enabled(_lc) - -/* - * @lc: context - * @device: device name, absolute device path or NULL to reset the current setting - * - * Sets device, absolute paths (e.g. "/dev/loop<N>") are unchanged, device - * names ("loop<N>") are converted to the path (/dev/loop<N> or to - * /dev/loop/<N>) - * - * Returns: <0 on error, 0 on success - */ -int loopcxt_set_device(struct loopdev_cxt *lc, const char *device) -{ - if (!lc) - return -EINVAL; - - if (lc->fd >= 0) { - close(lc->fd); - DBG(lc, loopdev_debug("closing old open fd")); - } - lc->fd = -1; - lc->mode = 0; - lc->has_info = 0; - lc->info_failed = 0; - *lc->device = '\0'; - memset(&lc->info, 0, sizeof(lc->info)); - - /* set new */ - if (device) { - if (*device != '/') { - const char *dir = _PATH_DEV; - - /* compose device name for /dev/loop<n> or /dev/loop/<n> */ - if (lc->flags & LOOPDEV_FL_DEVSUBDIR) { - if (strlen(device) < 5) - return -1; - device += 4; - dir = _PATH_DEV_LOOP "/"; /* _PATH_DEV uses tailing slash */ - } - snprintf(lc->device, sizeof(lc->device), "%s%s", - dir, device); - } else { - strncpy(lc->device, device, sizeof(lc->device)); - lc->device[sizeof(lc->device) - 1] = '\0'; - } - DBG(lc, loopdev_debug("%s successfully assigned", device)); - } - - sysfs_deinit(&lc->sysfs); - return 0; -} - -int loopcxt_has_device(struct loopdev_cxt *lc) -{ - return lc && *lc->device; -} - -/* - * @lc: context - * @flags: LOOPDEV_FL_* flags - * - * Initilize loop handler. - * - * We have two sets of the flags: - * - * * LOOPDEV_FL_* flags control loopcxt_* API behavior - * - * * LO_FLAGS_* are kernel flags used for LOOP_{SET,GET}_STAT64 ioctls - * - * Note about LOOPDEV_FL_{RDONLY,RDWR} flags. These flags are used for open(2) - * syscall to open loop device. By default is the device open read-only. - * - * The expection is loopcxt_setup_device(), where the device is open read-write - * if LO_FLAGS_READ_ONLY flags is not set (see loopcxt_set_flags()). - * - * Returns: <0 on error, 0 on success. - */ -int loopcxt_init(struct loopdev_cxt *lc, int flags) -{ - int rc; - struct stat st; - struct loopdev_cxt dummy = UL_LOOPDEVCXT_EMPTY; - - if (!lc) - return -EINVAL; - - memcpy(lc, &dummy, sizeof(dummy)); - lc->flags = flags; - - if (getenv("LOOPDEV_DEBUG")) - loopcxt_enable_debug(lc, TRUE); - - rc = loopcxt_set_device(lc, NULL); - if (rc) - return rc; - - if (stat(_PATH_SYS_BLOCK, &st) || !S_ISDIR(st.st_mode)) { - lc->flags |= LOOPDEV_FL_NOSYSFS; - lc->flags &= ~LOOPDEV_FL_NOIOCTL; - DBG(lc, loopdev_debug("init: disable /sys usage")); - } - - if (!(lc->flags & LOOPDEV_FL_NOSYSFS) && - get_linux_version() >= KERNEL_VERSION(2,6,37)) { - /* - * Use only sysfs for basic information about loop devices - */ - lc->flags |= LOOPDEV_FL_NOIOCTL; - DBG(lc, loopdev_debug("init: ignore ioctls")); - } - - if (!(lc->flags & LOOPDEV_FL_CONTROL) && !stat(_PATH_DEV_LOOPCTL, &st)) { - lc->flags |= LOOPDEV_FL_CONTROL; - DBG(lc, loopdev_debug("init: loop-control detected ")); - } - - return 0; -} - -/* - * @lc: context - * - * Deinitialize loop context - */ -void loopcxt_deinit(struct loopdev_cxt *lc) -{ - int errsv = errno; - - if (!lc) - return; - - DBG(lc, loopdev_debug("de-initialize")); - - free(lc->filename); - lc->filename = NULL; - - ignore_result( loopcxt_set_device(lc, NULL) ); - loopcxt_deinit_iterator(lc); - - errno = errsv; -} - -/* - * @lc: context - * @enable: TRUE/FALSE - * - * Enabled/disables debug messages - */ -void loopcxt_enable_debug(struct loopdev_cxt *lc, int enable) -{ - if (lc) - lc->debug = enable ? 1 : 0; -} - -/* - * @lc: context - * - * Returns newly allocated device path. - */ -char *loopcxt_strdup_device(struct loopdev_cxt *lc) -{ - if (!lc || !lc->device || !*lc->device) - return NULL; - return strdup(lc->device); -} - -/* - * @lc: context - * - * Returns pointer device name in the @lc struct. - */ -const char *loopcxt_get_device(struct loopdev_cxt *lc) -{ - return lc && lc->device && *lc->device ? lc->device : NULL; -} - -/* - * @lc: context - * - * Returns pointer to the sysfs context (see lib/sysfs.c) - */ -struct sysfs_cxt *loopcxt_get_sysfs(struct loopdev_cxt *lc) -{ - if (!lc || !*lc->device || (lc->flags & LOOPDEV_FL_NOSYSFS)) - return NULL; - - if (!lc->sysfs.devno) { - dev_t devno = sysfs_devname_to_devno(lc->device, NULL); - if (!devno) { - DBG(lc, loopdev_debug("sysfs: failed devname to devno")); - return NULL; - } - if (sysfs_init(&lc->sysfs, devno, NULL)) { - DBG(lc, loopdev_debug("sysfs: init failed")); - return NULL; - } - } - - return &lc->sysfs; -} - -/* - * @lc: context - * - * Returns: file descriptor to the open loop device or <0 on error. The mode - * depends on LOOPDEV_FL_{RDWR,RDONLY} context flags. Default is - * read-only. - */ -int loopcxt_get_fd(struct loopdev_cxt *lc) -{ - if (!lc || !*lc->device) - return -EINVAL; - - if (lc->fd < 0) { - lc->mode = lc->flags & LOOPDEV_FL_RDWR ? O_RDWR : O_RDONLY; - lc->fd = open(lc->device, lc->mode); - DBG(lc, loopdev_debug("open %s [%s]: %s", lc->device, - lc->flags & LOOPDEV_FL_RDWR ? "rw" : "ro", - lc->fd < 0 ? "failed" : "ok")); - } - return lc->fd; -} - -int loopcxt_set_fd(struct loopdev_cxt *lc, int fd, int mode) -{ - if (!lc) - return -EINVAL; - - lc->fd = fd; - lc->mode = mode; - return 0; -} - -/* - * @lc: context - * @flags: LOOPITER_FL_* flags - * - * Iterator allows to scan list of the free or used loop devices. - * - * Returns: <0 on error, 0 on success - */ -int loopcxt_init_iterator(struct loopdev_cxt *lc, int flags) -{ - struct loopdev_iter *iter; - struct stat st; - - if (!lc) - return -EINVAL; - - DBG(lc, loopdev_debug("iter: initialize")); - - iter = &lc->iter; - - /* always zeroize - */ - memset(iter, 0, sizeof(*iter)); - iter->ncur = -1; - iter->flags = flags; - iter->default_check = 1; - - if (!lc->extra_check) { - /* - * Check for /dev/loop/<N> subdirectory - */ - if (!(lc->flags & LOOPDEV_FL_DEVSUBDIR) && - stat(_PATH_DEV_LOOP, &st) == 0 && S_ISDIR(st.st_mode)) - lc->flags |= LOOPDEV_FL_DEVSUBDIR; - - lc->extra_check = 1; - } - return 0; -} - -/* - * @lc: context - * - * Returns: <0 on error, 0 on success - */ -int loopcxt_deinit_iterator(struct loopdev_cxt *lc) -{ - struct loopdev_iter *iter; - - if (!lc) - return -EINVAL; - - DBG(lc, loopdev_debug("iter: de-initialize")); - - iter = &lc->iter; - - free(iter->minors); - if (iter->proc) - fclose(iter->proc); - if (iter->sysblock) - closedir(iter->sysblock); - iter->minors = NULL; - iter->proc = NULL; - iter->sysblock = NULL; - iter->done = 1; - return 0; -} - -/* - * Same as loopcxt_set_device, but also checks if the device is - * associeted with any file. - * - * Returns: <0 on error, 0 on success, 1 device does not match with - * LOOPITER_FL_{USED,FREE} flags. - */ -static int loopiter_set_device(struct loopdev_cxt *lc, const char *device) -{ - int rc = loopcxt_set_device(lc, device); - int used; - - if (rc) - return rc; - - if (!(lc->iter.flags & LOOPITER_FL_USED) && - !(lc->iter.flags & LOOPITER_FL_FREE)) - return 0; /* caller does not care about device status */ - - used = loopcxt_get_offset(lc, NULL) == 0; - - if ((lc->iter.flags & LOOPITER_FL_USED) && used) - return 0; - - if ((lc->iter.flags & LOOPITER_FL_FREE) && !used) - return 0; - - DBG(lc, loopdev_debug("iter: unset device")); - ignore_result( loopcxt_set_device(lc, NULL) ); - return 1; -} - -static int cmpnum(const void *p1, const void *p2) -{ - return (((* (int *) p1) > (* (int *) p2)) - - ((* (int *) p1) < (* (int *) p2))); -} - -/* - * The classic scandir() is more expensive and less portable. - * We needn't full loop device names -- loop numbers (loop<N>) - * are enough. - */ -static int loop_scandir(const char *dirname, int **ary, int hasprefix) -{ - DIR *dir; - struct dirent *d; - unsigned int n, count = 0, arylen = 0; - - if (!dirname || !ary) - return 0; - dir = opendir(dirname); - if (!dir) - return 0; - free(*ary); - *ary = NULL; - - while((d = readdir(dir))) { -#ifdef _DIRENT_HAVE_D_TYPE - if (d->d_type != DT_BLK && d->d_type != DT_UNKNOWN && - d->d_type != DT_LNK) - continue; -#endif - if (!strcmp(d->d_name, ".") || !strcmp(d->d_name, "..")) - continue; - - if (hasprefix) { - /* /dev/loop<N> */ - if (sscanf(d->d_name, "loop%u", &n) != 1) - continue; - } else { - /* /dev/loop/<N> */ - char *end = NULL; - - n = strtol(d->d_name, &end, 10); - if (d->d_name == end || (end && *end) || errno) - continue; - } - if (n < LOOPDEV_DEFAULT_NNODES) - continue; /* ignore loop<0..7> */ - - if (count + 1 > arylen) { - int *tmp; - - arylen += 1; - - tmp = realloc(*ary, arylen * sizeof(int)); - if (!tmp) { - free(*ary); - closedir(dir); - return -1; - } - *ary = tmp; - } - if (*ary) - (*ary)[count++] = n; - } - if (count && *ary) - qsort(*ary, count, sizeof(int), cmpnum); - - closedir(dir); - return count; -} - -/* - * Set the next *used* loop device according to /proc/partitions. - * - * Loop devices smaller than 512 bytes are invisible for this function. - */ -static int loopcxt_next_from_proc(struct loopdev_cxt *lc) -{ - struct loopdev_iter *iter = &lc->iter; - char buf[BUFSIZ]; - - DBG(lc, loopdev_debug("iter: scan /proc/partitions")); - - if (!iter->proc) - iter->proc = fopen(_PATH_PROC_PARTITIONS, "r"); - if (!iter->proc) - return 1; - - while (fgets(buf, sizeof(buf), iter->proc)) { - unsigned int m; - char name[128 + 1]; - - - if (sscanf(buf, " %u %*s %*s %128[^\n ]", - &m, name) != 2 || m != LOOPDEV_MAJOR) - continue; - - DBG(lc, loopdev_debug("iter: check %s", name)); - - if (loopiter_set_device(lc, name) == 0) - return 0; - } - - return 1; -} - -/* - * Set the next *used* loop device according to - * /sys/block/loopN/loop/backing_file (kernel >= 2.6.37 is required). - * - * This is preferred method. - */ -static int loopcxt_next_from_sysfs(struct loopdev_cxt *lc) -{ - struct loopdev_iter *iter = &lc->iter; - struct dirent *d; - int fd; - - DBG(lc, loopdev_debug("iter: scan /sys/block")); - - if (!iter->sysblock) - iter->sysblock = opendir(_PATH_SYS_BLOCK); - - if (!iter->sysblock) - return 1; - - fd = dirfd(iter->sysblock); - - while ((d = readdir(iter->sysblock))) { - char name[256]; - struct stat st; - - DBG(lc, loopdev_debug("iter: check %s", d->d_name)); - - if (strcmp(d->d_name, ".") == 0 - || strcmp(d->d_name, "..") == 0 - || strncmp(d->d_name, "loop", 4) != 0) - continue; - - snprintf(name, sizeof(name), "%s/loop/backing_file", d->d_name); - if (fstat_at(fd, _PATH_SYS_BLOCK, name, &st, 0) != 0) - continue; - - if (loopiter_set_device(lc, d->d_name) == 0) - return 0; - } - - return 1; -} - -/* - * @lc: context, has to initialized by loopcxt_init_iterator() - * - * Returns: 0 on success, -1 on error, 1 at the end of scanning. The details - * about the current loop device are available by - * loopcxt_get_{fd,backing_file,device,offset, ...} functions. - */ -int loopcxt_next(struct loopdev_cxt *lc) -{ - struct loopdev_iter *iter; - - if (!lc) - return -EINVAL; - - DBG(lc, loopdev_debug("iter: next")); - - iter = &lc->iter; - if (iter->done) - return 1; - - /* A) Look for used loop devices in /proc/partitions ("losetup -a" only) - */ - if (iter->flags & LOOPITER_FL_USED) { - int rc; - - if (loopcxt_sysfs_available(lc)) - rc = loopcxt_next_from_sysfs(lc); - else - rc = loopcxt_next_from_proc(lc); - if (rc == 0) - return 0; - goto done; - } - - /* B) Classic way, try first eight loop devices (default number - * of loop devices). This is enough for 99% of all cases. - */ - if (iter->default_check) { - DBG(lc, loopdev_debug("iter: next: default check")); - for (++iter->ncur; iter->ncur < LOOPDEV_DEFAULT_NNODES; - iter->ncur++) { - char name[16]; - snprintf(name, sizeof(name), "loop%d", iter->ncur); - - if (loopiter_set_device(lc, name) == 0) - return 0; - } - iter->default_check = 0; - } - - /* C) the worst possibility, scan whole /dev or /dev/loop/<N> - */ - if (!iter->minors) { - DBG(lc, loopdev_debug("iter: next: scan /dev")); - iter->nminors = (lc->flags & LOOPDEV_FL_DEVSUBDIR) ? - loop_scandir(_PATH_DEV_LOOP, &iter->minors, 0) : - loop_scandir(_PATH_DEV, &iter->minors, 1); - iter->ncur = -1; - } - for (++iter->ncur; iter->ncur < iter->nminors; iter->ncur++) { - char name[16]; - snprintf(name, sizeof(name), "loop%d", iter->minors[iter->ncur]); - - if (loopiter_set_device(lc, name) == 0) - return 0; - } -done: - loopcxt_deinit_iterator(lc); - return 1; -} - -/* - * @device: path to device - */ -int is_loopdev(const char *device) -{ - struct stat st; - - if (!device) - return 0; - - return (stat(device, &st) == 0 && - S_ISBLK(st.st_mode) && - major(st.st_rdev) == LOOPDEV_MAJOR); -} - -/* - * @lc: context - * - * Returns result from LOOP_GET_STAT64 ioctl or NULL on error. - */ -struct loop_info64 *loopcxt_get_info(struct loopdev_cxt *lc) -{ - int fd; - - if (!lc || lc->info_failed) - return NULL; - if (lc->has_info) - return &lc->info; - - fd = loopcxt_get_fd(lc); - if (fd < 0) - return NULL; - - if (ioctl(fd, LOOP_GET_STATUS64, &lc->info) == 0) { - lc->has_info = 1; - lc->info_failed = 0; - DBG(lc, loopdev_debug("reading loop_info64 OK")); - return &lc->info; - } else { - lc->info_failed = 1; - DBG(lc, loopdev_debug("reading loop_info64 FAILED")); - } - - return NULL; -} - -/* - * @lc: context - * - * Returns (allocated) string with path to the file assicieted - * with the current loop device. - */ -char *loopcxt_get_backing_file(struct loopdev_cxt *lc) -{ - struct sysfs_cxt *sysfs = loopcxt_get_sysfs(lc); - char *res = NULL; - - if (sysfs) - /* - * This is always preffered, the loop_info64 - * has too small buffer for the filename. - */ - res = sysfs_strdup(sysfs, "loop/backing_file"); - - if (!res && loopcxt_ioctl_enabled(lc)) { - struct loop_info64 *lo = loopcxt_get_info(lc); - - if (lo) { - lo->lo_file_name[LO_NAME_SIZE - 2] = '*'; - lo->lo_file_name[LO_NAME_SIZE - 1] = '\0'; - res = strdup((char *) lo->lo_file_name); - } - } - - DBG(lc, loopdev_debug("get_backing_file [%s]", res)); - return res; -} - -/* - * @lc: context - * @offset: returns offset number for the given device - * - * Returns: <0 on error, 0 on success - */ -int loopcxt_get_offset(struct loopdev_cxt *lc, uint64_t *offset) -{ - struct sysfs_cxt *sysfs = loopcxt_get_sysfs(lc); - int rc = -EINVAL; - - if (sysfs) - rc = sysfs_read_u64(sysfs, "loop/offset", offset); - - if (rc && loopcxt_ioctl_enabled(lc)) { - struct loop_info64 *lo = loopcxt_get_info(lc); - if (lo) { - if (offset) - *offset = lo->lo_offset; - rc = 0; - } - } - - DBG(lc, loopdev_debug("get_offset [rc=%d]", rc)); - return rc; -} - -/* - * @lc: context - * @sizelimit: returns size limit for the given device - * - * Returns: <0 on error, 0 on success - */ -int loopcxt_get_sizelimit(struct loopdev_cxt *lc, uint64_t *size) -{ - struct sysfs_cxt *sysfs = loopcxt_get_sysfs(lc); - int rc = -EINVAL; - - if (sysfs) - rc = sysfs_read_u64(sysfs, "loop/sizelimit", size); - - if (rc && loopcxt_ioctl_enabled(lc)) { - struct loop_info64 *lo = loopcxt_get_info(lc); - if (lo) { - if (size) - *size = lo->lo_sizelimit; - rc = 0; - } - } - - DBG(lc, loopdev_debug("get_sizelimit [rc=%d]", rc)); - return rc; -} - -/* - * @lc: context - * @devno: returns encryption type - * - * Cryptoloop is DEPRECATED! - * - * Returns: <0 on error, 0 on success - */ -int loopcxt_get_encrypt_type(struct loopdev_cxt *lc, uint32_t *type) -{ - struct loop_info64 *lo = loopcxt_get_info(lc); - int rc = -EINVAL; - - if (lo) { - if (type) - *type = lo->lo_encrypt_type; - rc = 0; - } - DBG(lc, loopdev_debug("get_encrypt_type [rc=%d]", rc)); - return rc; -} - -/* - * @lc: context - * @devno: returns crypt name - * - * Cryptoloop is DEPRECATED! - * - * Returns: <0 on error, 0 on success - */ -const char *loopcxt_get_crypt_name(struct loopdev_cxt *lc) -{ - struct loop_info64 *lo = loopcxt_get_info(lc); - - if (lo) - return (char *) lo->lo_crypt_name; - - DBG(lc, loopdev_debug("get_crypt_name failed")); - return NULL; -} - -/* - * @lc: context - * @devno: returns backing file devno - * - * Returns: <0 on error, 0 on success - */ -int loopcxt_get_backing_devno(struct loopdev_cxt *lc, dev_t *devno) -{ - struct loop_info64 *lo = loopcxt_get_info(lc); - int rc = -EINVAL; - - if (lo) { - if (devno) - *devno = lo->lo_device; - rc = 0; - } - DBG(lc, loopdev_debug("get_backing_devno [rc=%d]", rc)); - return rc; -} - -/* - * @lc: context - * @ino: returns backing file inode - * - * Returns: <0 on error, 0 on success - */ -int loopcxt_get_backing_inode(struct loopdev_cxt *lc, ino_t *ino) -{ - struct loop_info64 *lo = loopcxt_get_info(lc); - int rc = -EINVAL; - - if (lo) { - if (ino) - *ino = lo->lo_inode; - rc = 0; - } - DBG(lc, loopdev_debug("get_backing_inode [rc=%d]", rc)); - return rc; -} - -/* - * Check if the kernel supports partitioned loop devices. - * - * Notes: - * - kernels < 3.2 support partitioned loop devices and PT scanning - * only if max_part= module paremeter is non-zero - * - * - kernels >= 3.2 always support partitioned loop devices - * - * - kernels >= 3.2 always support BLKPG_{ADD,DEL}_PARTITION ioctls - * - * - kernels >= 3.2 enable PT scanner only if max_part= is non-zero or if the - * LO_FLAGS_PARTSCAN flag is set for the device. The PT scanner is disabled - * by default. - * - * See kernel commit e03c8dd14915fabc101aa495828d58598dc5af98. - */ -int loopmod_supports_partscan(void) -{ - int rc, ret = 0; - FILE *f; - - if (get_linux_version() >= KERNEL_VERSION(3,2,0)) - return 1; - - f = fopen("/sys/module/loop/parameters/max_part", "r"); - if (!f) - return 0; - rc = fscanf(f, "%d", &ret); - fclose(f); - return rc == 1 ? ret : 0; -} - -/* - * @lc: context - * - * Returns: 1 if the partscan flags is set *or* (for old kernels) partitions - * scannig is enabled for all loop devices. - */ -int loopcxt_is_partscan(struct loopdev_cxt *lc) -{ - struct sysfs_cxt *sysfs = loopcxt_get_sysfs(lc); - - if (sysfs) { - /* kernel >= 3.2 */ - int fl; - if (sysfs_read_int(sysfs, "loop/partscan", &fl) == 0) - return fl; - } - - /* old kernels (including kernels without loopN/loop/<flags> directory */ - return loopmod_supports_partscan(); -} - -/* - * @lc: context - * - * Returns: 1 if the autoclear flags is set. - */ -int loopcxt_is_autoclear(struct loopdev_cxt *lc) -{ - struct sysfs_cxt *sysfs = loopcxt_get_sysfs(lc); - - if (sysfs) { - int fl; - if (sysfs_read_int(sysfs, "loop/autoclear", &fl) == 0) - return fl; - } - - if (loopcxt_ioctl_enabled(lc)) { - struct loop_info64 *lo = loopcxt_get_info(lc); - if (lo) - return lo->lo_flags & LO_FLAGS_AUTOCLEAR; - } - return 0; -} - -/* - * @lc: context - * - * Returns: 1 if the readonly flags is set. - */ -int loopcxt_is_readonly(struct loopdev_cxt *lc) -{ - struct sysfs_cxt *sysfs = loopcxt_get_sysfs(lc); - - if (sysfs) { - int fl; - if (sysfs_read_int(sysfs, "ro", &fl) == 0) - return fl; - } - - if (loopcxt_ioctl_enabled(lc)) { - struct loop_info64 *lo = loopcxt_get_info(lc); - if (lo) - return lo->lo_flags & LO_FLAGS_READ_ONLY; - } - return 0; -} - -/* - * @lc: context - * @st: backing file stat or NULL - * @backing_file: filename - * @offset: offset - * @flags: LOOPDEV_FL_OFFSET if @offset should not be ignored - * - * Returns 1 if the current @lc loopdev is associated with the given backing - * file. Note that the preferred way is to use devno and inode number rather - * than filename. The @backing_file filename is poor solution usable in case - * that you don't have rights to call stat(). - * - * Don't forget that old kernels provide very restricted (in size) backing - * filename by LOOP_GET_STAT64 ioctl only. - */ -int loopcxt_is_used(struct loopdev_cxt *lc, - struct stat *st, - const char *backing_file, - uint64_t offset, - int flags) -{ - ino_t ino; - dev_t dev; - - if (!lc) - return 0; - - DBG(lc, loopdev_debug("checking %s vs. %s", - loopcxt_get_device(lc), - backing_file)); - - if (st && loopcxt_get_backing_inode(lc, &ino) == 0 && - loopcxt_get_backing_devno(lc, &dev) == 0) { - - if (ino == st->st_ino && dev == st->st_dev) - goto found; - - /* don't use filename if we have devno and inode */ - return 0; - } - - /* poor man's solution */ - if (backing_file) { - char *name = loopcxt_get_backing_file(lc); - int rc = name && strcmp(name, backing_file) == 0; - - free(name); - if (rc) - goto found; - } - - return 0; -found: - if (flags & LOOPDEV_FL_OFFSET) { - uint64_t off; - - return loopcxt_get_offset(lc, &off) == 0 && off == offset; - } - return 1; -} - -/* - * The setting is removed by loopcxt_set_device() loopcxt_next()! - */ -int loopcxt_set_offset(struct loopdev_cxt *lc, uint64_t offset) -{ - if (!lc) - return -EINVAL; - lc->info.lo_offset = offset; - - DBG(lc, loopdev_debug("set offset=%jd", offset)); - return 0; -} - -/* - * The setting is removed by loopcxt_set_device() loopcxt_next()! - */ -int loopcxt_set_sizelimit(struct loopdev_cxt *lc, uint64_t sizelimit) -{ - if (!lc) - return -EINVAL; - lc->info.lo_sizelimit = sizelimit; - - DBG(lc, loopdev_debug("set sizelimit=%jd", sizelimit)); - return 0; -} - -/* - * @lc: context - * @flags: kernel LO_FLAGS_{READ_ONLY,USE_AOPS,AUTOCLEAR} flags - * - * The setting is removed by loopcxt_set_device() loopcxt_next()! - * - * Returns: 0 on success, <0 on error. - */ -int loopcxt_set_flags(struct loopdev_cxt *lc, uint32_t flags) -{ - if (!lc) - return -EINVAL; - lc->info.lo_flags = flags; - - DBG(lc, loopdev_debug("set flags=%u", (unsigned) flags)); - return 0; -} - -/* - * @lc: context - * @filename: backing file path (the path will be canonicalized) - * - * The setting is removed by loopcxt_set_device() loopcxt_next()! - * - * Returns: 0 on success, <0 on error. - */ -int loopcxt_set_backing_file(struct loopdev_cxt *lc, const char *filename) -{ - if (!lc) - return -EINVAL; - - lc->filename = canonicalize_path(filename); - if (!lc->filename) - return -errno; - - strncpy((char *)lc->info.lo_file_name, lc->filename, LO_NAME_SIZE); - lc->info.lo_file_name[LO_NAME_SIZE- 1] = '\0'; - - DBG(lc, loopdev_debug("set backing file=%s", lc->info.lo_file_name)); - return 0; -} - -/* - * @cl: context - * - * Associate the current device (see loopcxt_{set,get}_device()) with - * a file (see loopcxt_set_backing_file()). - * - * The device is initialized read-write by default. If you want read-only - * device then set LO_FLAGS_READ_ONLY by loopcxt_set_flags(). The LOOPDEV_FL_* - * flags are ignored and modified according to LO_FLAGS_*. - * - * If the device is already open by loopcxt_get_fd() then this setup device - * function will re-open the device to fix read/write mode. - * - * The device is also initialized read-only if the backing file is not - * possible to open read-write (e.g. read-only FS). - * - * Returns: <0 on error, 0 on success. - */ -int loopcxt_setup_device(struct loopdev_cxt *lc) -{ - int file_fd, dev_fd, mode = O_RDWR, rc = -1; - - if (!lc || !*lc->device || !lc->filename) - return -EINVAL; - - DBG(lc, loopdev_debug("device setup requested")); - - /* - * Open backing file and device - */ - if (lc->info.lo_flags & LO_FLAGS_READ_ONLY) - mode = O_RDONLY; - - if ((file_fd = open(lc->filename, mode)) < 0) { - if (mode != O_RDONLY && (errno == EROFS || errno == EACCES)) - file_fd = open(lc->filename, mode = O_RDONLY); - - if (file_fd < 0) { - DBG(lc, loopdev_debug("open backing file failed: %m")); - return -errno; - } - } - DBG(lc, loopdev_debug("setup: backing file open: OK")); - - if (lc->fd != -1 && lc->mode != mode) { - DBG(lc, loopdev_debug("closing already open device (mode mismatch)")); - close(lc->fd); - lc->fd = -1; - lc->mode = 0; - } - - if (mode == O_RDONLY) { - lc->flags |= LOOPDEV_FL_RDONLY; /* open() mode */ - lc->info.lo_flags |= LO_FLAGS_READ_ONLY; /* kernel loopdev mode */ - } else { - lc->flags |= LOOPDEV_FL_RDWR; /* open() mode */ - lc->info.lo_flags &= ~LO_FLAGS_READ_ONLY; - lc->flags &= ~LOOPDEV_FL_RDONLY; - } - - dev_fd = loopcxt_get_fd(lc); - if (dev_fd < 0) { - rc = -errno; - goto err; - } - - DBG(lc, loopdev_debug("setup: device open: OK")); - - /* - * Set FD - */ - if (ioctl(dev_fd, LOOP_SET_FD, file_fd) < 0) { - rc = -errno; - DBG(lc, loopdev_debug("LOOP_SET_FD failed: %m")); - goto err; - } - - DBG(lc, loopdev_debug("setup: LOOP_SET_FD: OK")); - - close(file_fd); - file_fd = -1; - - if (ioctl(dev_fd, LOOP_SET_STATUS64, &lc->info)) { - DBG(lc, loopdev_debug("LOOP_SET_STATUS64 failed: %m")); - goto err; - } - - DBG(lc, loopdev_debug("setup: LOOP_SET_STATUS64: OK")); - - memset(&lc->info, 0, sizeof(lc->info)); - lc->has_info = 0; - lc->info_failed = 0; - - DBG(lc, loopdev_debug("setup success [rc=0]")); - return 0; -err: - if (file_fd >= 0) - close(file_fd); - if (dev_fd >= 0) - ioctl(dev_fd, LOOP_CLR_FD, 0); - - DBG(lc, loopdev_debug("setup failed [rc=%d]", rc)); - return rc; -} - -int loopcxt_delete_device(struct loopdev_cxt *lc) -{ - int fd = loopcxt_get_fd(lc); - - if (fd < 0) - return -EINVAL; - - if (ioctl(fd, LOOP_CLR_FD, 0) < 0) { - DBG(lc, loopdev_debug("LOOP_CLR_FD failed: %m")); - return -errno; - } - - DBG(lc, loopdev_debug("device removed")); - return 0; -} - -/* - * Note that LOOP_CTL_GET_FREE ioctl is supported since kernel 3.1. In older - * kernels we have to check all loop devices to found unused one. - * - * See kernel commit 770fe30a46a12b6fb6b63fbe1737654d28e8484. - */ -int loopcxt_find_unused(struct loopdev_cxt *lc) -{ - int rc = -1; - - DBG(lc, loopdev_debug("find_unused requested")); - - if (lc->flags & LOOPDEV_FL_CONTROL) { - int ctl = open(_PATH_DEV_LOOPCTL, O_RDWR); - - if (ctl >= 0) - rc = ioctl(ctl, LOOP_CTL_GET_FREE); - if (rc >= 0) { - char name[16]; - snprintf(name, sizeof(name), "loop%d", rc); - - rc = loopiter_set_device(lc, name); - } - if (ctl >= 0) - close(ctl); - DBG(lc, loopdev_debug("find_unused by loop-control [rc=%d]", rc)); - } - - if (rc < 0) { - rc = loopcxt_init_iterator(lc, LOOPITER_FL_FREE); - if (rc) - return rc; - - rc = loopcxt_next(lc); - loopcxt_deinit_iterator(lc); - DBG(lc, loopdev_debug("find_unused by scan [rc=%d]", rc)); - } - return rc; -} - - - -/* - * Return: TRUE/FALSE - */ -int loopdev_is_autoclear(const char *device) -{ - struct loopdev_cxt lc; - int rc; - - if (!device) - return 0; - - rc = loopcxt_init(&lc, 0); - if (!rc) - rc = loopcxt_set_device(&lc, device); - if (!rc) - rc = loopcxt_is_autoclear(&lc); - - loopcxt_deinit(&lc); - return rc; -} - -char *loopdev_get_backing_file(const char *device) -{ - struct loopdev_cxt lc; - char *res = NULL; - - if (!device) - return NULL; - if (loopcxt_init(&lc, 0)) - return NULL; - if (loopcxt_set_device(&lc, device) == 0) - res = loopcxt_get_backing_file(&lc); - - loopcxt_deinit(&lc); - return res; -} - -/* - * Returns: TRUE/FALSE - */ -int loopdev_is_used(const char *device, const char *filename, - uint64_t offset, int flags) -{ - struct loopdev_cxt lc; - struct stat st; - int rc = 0; - - if (!device || !filename) - return 0; - - rc = loopcxt_init(&lc, 0); - if (!rc) - rc = loopcxt_set_device(&lc, device); - if (rc) - return rc; - - rc = !stat(filename, &st); - rc = loopcxt_is_used(&lc, rc ? &st : NULL, filename, offset, flags); - - loopcxt_deinit(&lc); - return rc; -} - -int loopdev_delete(const char *device) -{ - struct loopdev_cxt lc; - int rc; - - if (!device) - return -EINVAL; - - rc = loopcxt_init(&lc, 0); - if (!rc) - rc = loopcxt_set_device(&lc, device); - if (!rc) - rc = loopcxt_delete_device(&lc); - loopcxt_deinit(&lc); - return rc; -} - -/* - * Returns: 0 = success, < 0 error, 1 not found - */ -int loopcxt_find_by_backing_file(struct loopdev_cxt *lc, const char *filename, - uint64_t offset, int flags) -{ - int rc, hasst; - struct stat st; - - if (!filename) - return -EINVAL; - - hasst = !stat(filename, &st); - - rc = loopcxt_init_iterator(lc, LOOPITER_FL_USED); - if (rc) - return rc; - - while ((rc = loopcxt_next(lc)) == 0) { - - if (loopcxt_is_used(lc, hasst ? &st : NULL, - filename, offset, flags)) - break; - } - - loopcxt_deinit_iterator(lc); - return rc; -} - -/* - * Returns allocated string with device name - */ -char *loopdev_find_by_backing_file(const char *filename, uint64_t offset, int flags) -{ - struct loopdev_cxt lc; - char *res = NULL; - - if (!filename) - return NULL; - - if (loopcxt_init(&lc, 0)) - return NULL; - if (loopcxt_find_by_backing_file(&lc, filename, offset, flags) == 0) - res = loopcxt_strdup_device(&lc); - loopcxt_deinit(&lc); - - return res; -} - -/* - * Returns number of loop devices associated with @file, if only one loop - * device is associeted with the given @filename and @loopdev is not NULL then - * @loopdev returns name of the device. - */ -int loopdev_count_by_backing_file(const char *filename, char **loopdev) -{ - struct loopdev_cxt lc; - int count = 0, rc; - - if (!filename) - return -1; - - rc = loopcxt_init(&lc, 0); - if (rc) - return rc; - if (loopcxt_init_iterator(&lc, LOOPITER_FL_USED)) - return -1; - - while(loopcxt_next(&lc) == 0) { - char *backing = loopcxt_get_backing_file(&lc); - - if (!backing || strcmp(backing, filename)) { - free(backing); - continue; - } - - free(backing); - if (loopdev && count == 0) - *loopdev = loopcxt_strdup_device(&lc); - count++; - } - - loopcxt_deinit(&lc); - - if (loopdev && count > 1) { - free(*loopdev); - *loopdev = NULL; - } - return count; -} - - -#ifdef TEST_PROGRAM_LOOPDEV -#include <errno.h> -#include <err.h> - -static void test_loop_info(const char *device, int flags, int debug) -{ - struct loopdev_cxt lc; - char *p; - uint64_t u64; - - if (loopcxt_init(&lc, flags)) - return; - loopcxt_enable_debug(&lc, debug); - - if (loopcxt_set_device(&lc, device)) - err(EXIT_FAILURE, "failed to set device"); - - p = loopcxt_get_backing_file(&lc); - printf("\tBACKING FILE: %s\n", p); - free(p); - - if (loopcxt_get_offset(&lc, &u64) == 0) - printf("\tOFFSET: %jd\n", u64); - - if (loopcxt_get_sizelimit(&lc, &u64) == 0) - printf("\tSIZE LIMIT: %jd\n", u64); - - printf("\tAUTOCLEAR: %s\n", loopcxt_is_autoclear(&lc) ? "YES" : "NOT"); - - loopcxt_deinit(&lc); -} - -static void test_loop_scan(int flags, int debug) -{ - struct loopdev_cxt lc; - int rc; - - if (loopcxt_init(&lc, 0)) - return; - loopcxt_enable_debug(&lc, debug); - - if (loopcxt_init_iterator(&lc, flags)) - err(EXIT_FAILURE, "iterator initlization failed"); - - while((rc = loopcxt_next(&lc)) == 0) { - const char *device = loopcxt_get_device(&lc); - - if (flags & LOOPITER_FL_USED) { - char *backing = loopcxt_get_backing_file(&lc); - printf("\t%s: %s\n", device, backing); - free(backing); - } else - printf("\t%s\n", device); - } - - if (rc < 0) - err(EXIT_FAILURE, "loopdevs scanning failed"); - - loopcxt_deinit(&lc); -} - -static int test_loop_setup(const char *filename, const char *device, int debug) -{ - struct loopdev_cxt lc; - int rc; - - rc = loopcxt_init(&lc, 0); - if (rc) - return rc; - loopcxt_enable_debug(&lc, debug); - - if (device) { - rc = loopcxt_set_device(&lc, device); - if (rc) - err(EXIT_FAILURE, "failed to set device: %s", device); - } - - do { - if (!device) { - rc = loopcxt_find_unused(&lc); - if (rc) - err(EXIT_FAILURE, "failed to find unused device"); - printf("Trying to use '%s'\n", loopcxt_get_device(&lc)); - } - - if (loopcxt_set_backing_file(&lc, filename)) - err(EXIT_FAILURE, "failed to set backing file"); - - rc = loopcxt_setup_device(&lc); - if (rc == 0) - break; /* success */ - - if (device || rc != -EBUSY) - err(EXIT_FAILURE, "failed to setup device for %s", - lc.filename); - - printf("device stolen...trying again\n"); - } while (1); - - loopcxt_deinit(&lc); - - return 0; -} - -int main(int argc, char *argv[]) -{ - int dbg; - - if (argc < 2) - goto usage; - - dbg = getenv("LOOPDEV_DEBUG") == NULL ? 0 : 1; - - if (argc == 3 && strcmp(argv[1], "--info") == 0) { - printf("---sysfs & ioctl:---\n"); - test_loop_info(argv[2], 0, dbg); - printf("---sysfs only:---\n"); - test_loop_info(argv[2], LOOPDEV_FL_NOIOCTL, dbg); - printf("---ioctl only:---\n"); - test_loop_info(argv[2], LOOPDEV_FL_NOSYSFS, dbg); - - } else if (argc == 2 && strcmp(argv[1], "--used") == 0) { - printf("---all used devices---\n"); - test_loop_scan(LOOPITER_FL_USED, dbg); - - } else if (argc == 2 && strcmp(argv[1], "--free") == 0) { - printf("---all free devices---\n"); - test_loop_scan(LOOPITER_FL_FREE, dbg); - - } else if (argc >= 3 && strcmp(argv[1], "--setup") == 0) { - test_loop_setup(argv[2], argv[3], dbg); - - } else if (argc == 3 && strcmp(argv[1], "--delete") == 0) { - if (loopdev_delete(argv[2])) - errx(EXIT_FAILURE, "failed to deinitialize device %s", argv[2]); - } else - goto usage; - - return EXIT_SUCCESS; - -usage: - errx(EXIT_FAILURE, "usage: \n" - " %1$s --info <device>\n" - " %1$s --free\n" - " %1$s --used\n" - " %1$s --setup <filename> [<device>]\n" - " %1$s --delete\n", - argv[0]); -} - -#endif /* TEST_PROGRAM */ |