/** * device.c - Low level device io functions. Originated from the Linux-NTFS project. * * Copyright (c) 2004-2013 Anton Altaparmakov * Copyright (c) 2004-2006 Szabolcs Szakacsits * Copyright (c) 2010 Jean-Pierre Andre * Copyright (c) 2008-2013 Tuxera Inc. * * This program/include file 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/include file 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 (in the main directory of the NTFS-3G * distribution in the file COPYING); if not, write to the Free Software * Foundation,Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */ #ifdef HAVE_CONFIG_H #include "config.h" #endif #ifdef HAVE_UNISTD_H #include #endif #ifdef HAVE_STDLIB_H #include #endif #ifdef HAVE_STRING_H #include #endif #ifdef HAVE_ERRNO_H #include #endif #ifdef HAVE_STDIO_H #include #endif #ifdef HAVE_SYS_TYPES_H #include #endif #ifdef HAVE_SYS_STAT_H #include #endif #ifdef HAVE_FCNTL_H #include #endif #ifdef HAVE_SYS_IOCTL_H #include #endif #ifdef HAVE_SYS_PARAM_H #include #endif #ifdef HAVE_SYS_MOUNT_H #include #endif #ifdef HAVE_SYS_DISK_H #include #endif #ifdef HAVE_LINUX_FD_H #include #endif #ifdef HAVE_LINUX_HDREG_H #include #endif #ifdef ENABLE_HD #include #endif #include "types.h" #include "mst.h" #include "debug.h" #include "device.h" #include "logging.h" #include "misc.h" #if defined(linux) && defined(_IO) && !defined(BLKGETSIZE) #define BLKGETSIZE _IO(0x12,96) /* Get device size in 512-byte blocks. */ #endif #if defined(linux) && defined(_IOR) && !defined(BLKGETSIZE64) #define BLKGETSIZE64 _IOR(0x12,114,size_t) /* Get device size in bytes. */ #endif #if defined(linux) && !defined(HDIO_GETGEO) #define HDIO_GETGEO 0x0301 /* Get device geometry. */ #endif #if defined(linux) && defined(_IO) && !defined(BLKSSZGET) # define BLKSSZGET _IO(0x12,104) /* Get device sector size in bytes. */ #endif #if defined(linux) && defined(_IO) && !defined(BLKBSZSET) # define BLKBSZSET _IOW(0x12,113,size_t) /* Set device block size in bytes. */ #endif /** * ntfs_device_alloc - allocate an ntfs device structure and pre-initialize it * @name: name of the device (must be present) * @state: initial device state (usually zero) * @dops: ntfs device operations to use with the device (must be present) * @priv_data: pointer to private data (optional) * * Allocate an ntfs device structure and pre-initialize it with the user- * specified device operations @dops, device state @state, device name @name, * and optional private data @priv_data. * * Note, @name is copied and can hence be freed after this functions returns. * * On success return a pointer to the allocated ntfs device structure and on * error return NULL with errno set to the error code returned by ntfs_malloc(). */ struct ntfs_device *ntfs_device_alloc(const char *name, const long state, struct ntfs_device_operations *dops, void *priv_data) { struct ntfs_device *dev; if (!name) { errno = EINVAL; return NULL; } dev = ntfs_malloc(sizeof(struct ntfs_device)); if (dev) { if (!(dev->d_name = strdup(name))) { int eo = errno; free(dev); errno = eo; return NULL; } dev->d_ops = dops; dev->d_state = state; dev->d_private = priv_data; dev->d_heads = -1; dev->d_sectors_per_track = -1; } return dev; } /** * ntfs_device_free - free an ntfs device structure * @dev: ntfs device structure to free * * Free the ntfs device structure @dev. * * Return 0 on success or -1 on error with errno set to the error code. The * following error codes are defined: * EINVAL Invalid pointer @dev. * EBUSY Device is still open. Close it before freeing it! */ int ntfs_device_free(struct ntfs_device *dev) { if (!dev) { errno = EINVAL; return -1; } if (NDevOpen(dev)) { errno = EBUSY; return -1; } free(dev->d_name); free(dev); return 0; } /* * Sync the device * * returns zero if successful. */ int ntfs_device_sync(struct ntfs_device *dev) { int ret; struct ntfs_device_operations *dops; if (NDevDirty(dev)) { dops = dev->d_ops; ret = dops->sync(dev); } else ret = 0; return ret; } /** * ntfs_pread - positioned read from disk * @dev: device to read from * @pos: position in device to read from * @count: number of bytes to read * @b: output data buffer * * This function will read @count bytes from device @dev at position @pos into * the data buffer @b. * * On success, return the number of successfully read bytes. If this number is * lower than @count this means that we have either reached end of file or * encountered an error during the read so that the read is partial. 0 means * end of file or nothing to read (@count is 0). * * On error and nothing has been read, return -1 with errno set appropriately * to the return code of either seek, read, or set to EINVAL in case of * invalid arguments. */ s64 ntfs_pread(struct ntfs_device *dev, const s64 pos, s64 count, void *b) { s64 br, total; struct ntfs_device_operations *dops; ntfs_log_trace("pos %lld, count %lld\n",(long long)pos,(long long)count); if (!b || count < 0 || pos < 0) { errno = EINVAL; return -1; } if (!count) return 0; dops = dev->d_ops; for (total = 0; count; count -= br, total += br) { br = dops->pread(dev, (char*)b + total, count, pos + total); /* If everything ok, continue. */ if (br > 0) continue; /* If EOF or error return number of bytes read. */ if (!br || total) return total; /* Nothing read and error, return error status. */ return br; } /* Finally, return the number of bytes read. */ return total; } /** * ntfs_pwrite - positioned write to disk * @dev: device to write to * @pos: position in file descriptor to write to * @count: number of bytes to write * @b: data buffer to write to disk * * This function will write @count bytes from data buffer @b to the device @dev * at position @pos. * * On success, return the number of successfully written bytes. If this number * is lower than @count this means that the write has been interrupted in * flight or that an error was encountered during the write so that the write * is partial. 0 means nothing was written (also return 0 when @count is 0). * * On error and nothing has been written, return -1 with errno set * appropriately to the return code of either seek, write, or set * to EINVAL in case of invalid arguments. */ s64 ntfs_pwrite(struct ntfs_device *dev, const s64 pos, s64 count, const void *b) { s64 written, total, ret = -1; struct ntfs_device_operations *dops; ntfs_log_trace("pos %lld, count %lld\n",(long long)pos,(long long)count); if (!b || count < 0 || pos < 0) { errno = EINVAL; goto out; } if (!count) return 0; if (NDevReadOnly(dev)) { errno = EROFS; goto out; } dops = dev->d_ops; NDevSetDirty(dev); for (total = 0; count; count -= written, total += written) { written = dops->pwrite(dev, (const char*)b + total, count, pos + total); /* If everything ok, continue. */ if (written > 0) continue; /* * If nothing written or error return number of bytes written. */ if (!written || total) break; /* Nothing written and error, return error status. */ total = written; break; } if (NDevSync(dev) && total && dops->sync(dev)) { total--; /* on sync error, return partially written */ } ret = total; out: return ret; } /** * ntfs_mst_pread - multi sector transfer (mst) positioned read * @dev: device to read from * @pos: position in file descriptor to read from * @count: number of blocks to read * @bksize: size of each block that needs mst deprotecting * @b: output data buffer * * Multi sector transfer (mst) positioned read. This function will read @count * blocks of size @bksize bytes each from device @dev at position @pos into the * the data buffer @b. * * On success, return the number of successfully read blocks. If this number is * lower than @count this means that we have reached end of file, that the read * was interrupted, or that an error was encountered during the read so that * the read is partial. 0 means end of file or nothing was read (also return 0 * when @count or @bksize are 0). * * On error and nothing was read, return -1 with errno set appropriately to the * return code of either seek, read, or set to EINVAL in case of invalid * arguments. * * NOTE: If an incomplete multi sector transfer has been detected the magic * will have been changed to magic_BAAD but no error will be returned. Thus it * is possible that we return count blocks as being read but that any number * (between zero and count!) of these blocks is actually subject to a multi * sector transfer error. This should be detected by the caller by checking for * the magic being "BAAD". */ s64 ntfs_mst_pread(struct ntfs_device *dev, const s64 pos, s64 count, const u32 bksize, void *b) { s64 br, i; if (bksize & (bksize - 1) || bksize % NTFS_BLOCK_SIZE) { errno = EINVAL; return -1; } /* Do the read. */ br = ntfs_pread(dev, pos, count * bksize, b); if (br < 0) return br; /* * Apply fixups to successfully read data, disregarding any errors * returned from the MST fixup function. This is because we want to * fixup everything possible and we rely on the fact that the "BAAD" * magic will be detected later on. */ count = br / bksize; for (i = 0; i < count; ++i) ntfs_mst_post_read_fixup((NTFS_RECORD*) ((u8*)b + i * bksize), bksize); /* Finally, return the number of complete blocks read. */ return count; } /** * ntfs_mst_pwrite - multi sector transfer (mst) positioned write * @dev: device to write to * @pos: position in file descriptor to write to * @count: number of blocks to write * @bksize: size of each block that needs mst protecting * @b: data buffer to write to disk * * Multi sector transfer (mst) positioned write. This function will write * @count blocks of size @bksize bytes each from data buffer @b to the device * @dev at position @pos. * * On success, return the number of successfully written blocks. If this number * is lower than @count this means that the write has been interrupted or that * an error was encountered during the write so that the write is partial. 0 * means nothing was written (also return 0 when @count or @bksize are 0). * * On error and nothing has been written, return -1 with errno set * appropriately to the return code of either seek, write, or set * to EINVAL in case of invalid arguments. * * NOTE: We mst protect the data, write it, then mst deprotect it using a quick * deprotect algorithm (no checking). This saves us from making a copy before * the write and at the same time causes the usn to be incremented in the * buffer. This conceptually fits in better with the idea that cached data is * always deprotected and protection is performed when the data is actually * going to hit the disk and the cache is immediately deprotected again * simulating an mst read on the written data. This way cache coherency is * achieved. */ s64 ntfs_mst_pwrite(struct ntfs_device *dev, const s64 pos, s64 count, const u32 bksize, void *b) { s64 written, i; if (count < 0 || bksize % NTFS_BLOCK_SIZE) { errno = EINVAL; return -1; } if (!count) return 0; /* Prepare data for writing. */ for (i = 0; i < count; ++i) { int err; err = ntfs_mst_pre_write_fixup((NTFS_RECORD*) ((u8*)b + i * bksize), bksize); if (err < 0) { /* Abort write at this position. */ if (!i) return err; count = i; break; } } /* Write the prepared data. */ written = ntfs_pwrite(dev, pos, count * bksize, b); /* Quickly deprotect the data again. */ for (i = 0; i < count; ++i) ntfs_mst_post_write_fixup((NTFS_RECORD*)((u8*)b + i * bksize)); if (written <= 0) return written; /* Finally, return the number of complete blocks written. */ return written / bksize; } /** * ntfs_cluster_read - read ntfs clusters * @vol: volume to read from * @lcn: starting logical cluster number * @count: number of clusters to read * @b: output data buffer * * Read @count ntfs clusters starting at logical cluster number @lcn from * volume @vol into buffer @b. Return number of clusters read or -1 on error, * with errno set to the error code. */ s64 ntfs_cluster_read(const ntfs_volume *vol, const s64 lcn, const s64 count, void *b) { s64 br; if (!vol || lcn < 0 || count < 0) { errno = EINVAL; return -1; } if (vol->nr_clusters < lcn + count) { errno = ESPIPE; ntfs_log_perror("Trying to read outside of volume " "(%lld < %lld)", (long long)vol->nr_clusters, (long long)lcn + count); return -1; } br = ntfs_pread(vol->dev, lcn << vol->cluster_size_bits, count << vol->cluster_size_bits, b); if (br < 0) { ntfs_log_perror("Error reading cluster(s)"); return br; } return br >> vol->cluster_size_bits; } /** * ntfs_cluster_write - write ntfs clusters * @vol: volume to write to * @lcn: starting logical cluster number * @count: number of clusters to write * @b: data buffer to write to disk * * Write @count ntfs clusters starting at logical cluster number @lcn from * buffer @b to volume @vol. Return the number of clusters written or -1 on * error, with errno set to the error code. */ s64 ntfs_cluster_write(const ntfs_volume *vol, const s64 lcn, const s64 count, const void *b) { s64 bw; if (!vol || lcn < 0 || count < 0) { errno = EINVAL; return -1; } if (vol->nr_clusters < lcn + count) { errno = ESPIPE; ntfs_log_perror("Trying to write outside of volume " "(%lld < %lld)", (long long)vol->nr_clusters, (long long)lcn + count); return -1; } if (!NVolReadOnly(vol)) bw = ntfs_pwrite(vol->dev, lcn << vol->cluster_size_bits, count << vol->cluster_size_bits, b); else bw = count << vol->cluster_size_bits; if (bw < 0) { ntfs_log_perror("Error writing cluster(s)"); return bw; } return bw >> vol->cluster_size_bits; } /** * ntfs_device_offset_valid - test if a device offset is valid * @dev: open device * @ofs: offset to test for validity * * Test if the offset @ofs is an existing location on the device described * by the open device structure @dev. * * Return 0 if it is valid and -1 if it is not valid. */ static int ntfs_device_offset_valid(struct ntfs_device *dev, s64 ofs) { char ch; if (dev->d_ops->seek(dev, ofs, SEEK_SET) >= 0 && dev->d_ops->read(dev, &ch, 1) == 1) return 0; return -1; } /** * ntfs_device_size_get - return the size of a device in blocks * @dev: open device * @block_size: block size in bytes in which to return the result * * Return the number of @block_size sized blocks in the device described by the * open device @dev. * * Adapted from e2fsutils-1.19, Copyright (C) 1995 Theodore Ts'o. * * On error return -1 with errno set to the error code. */ s64 ntfs_device_size_get(struct ntfs_device *dev, int block_size) { s64 high, low; if (!dev || block_size <= 0 || (block_size - 1) & block_size) { errno = EINVAL; return -1; } #ifdef BLKGETSIZE64 { u64 size; if (dev->d_ops->ioctl(dev, BLKGETSIZE64, &size) >= 0) { ntfs_log_debug("BLKGETSIZE64 nr bytes = %llu (0x%llx)\n", (unsigned long long)size, (unsigned long long)size); return (s64)size / block_size; } } #endif #ifdef BLKGETSIZE { unsigned long size; if (dev->d_ops->ioctl(dev, BLKGETSIZE, &size) >= 0) { ntfs_log_debug("BLKGETSIZE nr 512 byte blocks = %lu (0x%lx)\n", size, size); return (s64)size * 512 / block_size; } } #endif #ifdef FDGETPRM { struct floppy_struct this_floppy; if (dev->d_ops->ioctl(dev, FDGETPRM, &this_floppy) >= 0) { ntfs_log_debug("FDGETPRM nr 512 byte blocks = %lu (0x%lx)\n", (unsigned long)this_floppy.size, (unsigned long)this_floppy.size); return (s64)this_floppy.size * 512 / block_size; } } #endif #ifdef DIOCGMEDIASIZE { /* FreeBSD */ off_t size; if (dev->d_ops->ioctl(dev, DIOCGMEDIASIZE, &size) >= 0) { ntfs_log_debug("DIOCGMEDIASIZE nr bytes = %llu (0x%llx)\n", (unsigned long long)size, (unsigned long long)size); return (s64)size / block_size; } } #endif #ifdef DKIOCGETBLOCKCOUNT { /* Mac OS X */ uint64_t blocks; int sector_size; sector_size = ntfs_device_sector_size_get(dev); if (sector_size >= 0 && dev->d_ops->ioctl(dev, DKIOCGETBLOCKCOUNT, &blocks) >= 0) { ntfs_log_debug("DKIOCGETBLOCKCOUNT nr blocks = %llu (0x%llx)\n", (unsigned long long) blocks, (unsigned long long) blocks); return blocks * sector_size / block_size; } } #endif /* * We couldn't figure it out by using a specialized ioctl, * so do binary search to find the size of the device. */ low = 0LL; for (high = 1024LL; !ntfs_device_offset_valid(dev, high); high <<= 1) low = high; while (low < high - 1LL) { const s64 mid = (low + high) / 2; if (!ntfs_device_offset_valid(dev, mid)) low = mid; else high = mid; } dev->d_ops->seek(dev, 0LL, SEEK_SET); return (low + 1LL) / block_size; } /** * ntfs_device_partition_start_sector_get - get starting sector of a partition * @dev: open device * * On success, return the starting sector of the partition @dev in the parent * block device of @dev. On error return -1 with errno set to the error code. * * The following error codes are defined: * EINVAL Input parameter error * EOPNOTSUPP System does not support HDIO_GETGEO ioctl * ENOTTY @dev is a file or a device not supporting HDIO_GETGEO */ s64 ntfs_device_partition_start_sector_get(struct ntfs_device *dev) { if (!dev) { errno = EINVAL; return -1; } #ifdef HDIO_GETGEO { struct hd_geometry geo; if (!dev->d_ops->ioctl(dev, HDIO_GETGEO, &geo)) { ntfs_log_debug("HDIO_GETGEO start_sect = %lu (0x%lx)\n", geo.start, geo.start); return geo.start; } } #else errno = EOPNOTSUPP; #endif return -1; } static int ntfs_device_get_geo(struct ntfs_device *dev) { int err; if (!dev) { errno = EINVAL; return -1; } err = EOPNOTSUPP; #ifdef ENABLE_HD { hd_data_t *hddata; hd_t *hd, *devlist, *partlist = NULL; str_list_t *names; hd_res_t *res; const int d_name_len = strlen(dev->d_name) + 1; int done = 0; hddata = calloc(1, sizeof(*hddata)); if (!hddata) { err = ENOMEM; goto skip_hd; } /* List all "disk" class devices on the system. */ devlist = hd_list(hddata, hw_disk, 1, NULL); if (!devlist) { free(hddata); err = ENOMEM; goto skip_hd; } /* * Loop over each disk device looking for the device with the * same unix name as @dev. */ for (hd = devlist; hd; hd = hd->next) { if (hd->unix_dev_name && !strncmp(dev->d_name, hd->unix_dev_name, d_name_len)) goto got_hd; if (hd->unix_dev_name2 && !strncmp(dev->d_name, hd->unix_dev_name2, d_name_len)) goto got_hd; for (names = hd->unix_dev_names; names; names = names->next) { if (names->str && !strncmp(dev->d_name, names->str, d_name_len)) goto got_hd; } } /* * Device was not a whole disk device. Unless it is a file it * is likely to be a partition device. List all "partition" * class devices on the system. */ partlist = hd_list(hddata, hw_partition, 1, NULL); for (hd = partlist; hd; hd = hd->next) { if (hd->unix_dev_name && !strncmp(dev->d_name, hd->unix_dev_name, d_name_len)) goto got_part_hd; if (hd->unix_dev_name2 && !strncmp(dev->d_name, hd->unix_dev_name2, d_name_len)) goto got_part_hd; for (names = hd->unix_dev_names; names; names = names->next) { if (names->str && !strncmp(dev->d_name, names->str, d_name_len)) goto got_part_hd; } } /* Failed to find the device. Stop trying and clean up. */ goto end_hd; got_part_hd: /* Get the whole block device the partition device is on. */ hd = hd_get_device_by_idx(hddata, hd->attached_to); if (!hd) goto end_hd; got_hd: /* * @hd is now the whole block device either being formatted or * that the partition being formatted is on. * * Loop over each resource of the disk device looking for the * BIOS legacy geometry obtained from EDD which is what Windows * needs to boot. */ for (res = hd->res; res; res = res->next) { /* geotype 3 is BIOS legacy. */ if (res->any.type != res_disk_geo || res->disk_geo.geotype != 3) continue; dev->d_heads = res->disk_geo.heads; dev->d_sectors_per_track = res->disk_geo.sectors; done = 1; } end_hd: if (partlist) hd_free_hd_list(partlist); hd_free_hd_list(devlist); hd_free_hd_data(hddata); free(hddata); if (done) { ntfs_log_debug("EDD/BIOD legacy heads = %u, sectors " "per track = %u\n", dev->d_heads, dev->d_sectors_per_track); return 0; } } skip_hd: #endif #ifdef HDIO_GETGEO { struct hd_geometry geo; if (!dev->d_ops->ioctl(dev, HDIO_GETGEO, &geo)) { dev->d_heads = geo.heads; dev->d_sectors_per_track = geo.sectors; ntfs_log_debug("HDIO_GETGEO heads = %u, sectors per " "track = %u\n", dev->d_heads, dev->d_sectors_per_track); return 0; } err = errno; } #endif errno = err; return -1; } /** * ntfs_device_heads_get - get number of heads of device * @dev: open device * * On success, return the number of heads on the device @dev. On error return * -1 with errno set to the error code. * * The following error codes are defined: * EINVAL Input parameter error * EOPNOTSUPP System does not support HDIO_GETGEO ioctl * ENOTTY @dev is a file or a device not supporting HDIO_GETGEO * ENOMEM Not enough memory to complete the request */ int ntfs_device_heads_get(struct ntfs_device *dev) { if (!dev) { errno = EINVAL; return -1; } if (dev->d_heads == -1) { if (ntfs_device_get_geo(dev) == -1) return -1; if (dev->d_heads == -1) { errno = EINVAL; return -1; } } return dev->d_heads; } /** * ntfs_device_sectors_per_track_get - get number of sectors per track of device * @dev: open device * * On success, return the number of sectors per track on the device @dev. On * error return -1 with errno set to the error code. * * The following error codes are defined: * EINVAL Input parameter error * EOPNOTSUPP System does not support HDIO_GETGEO ioctl * ENOTTY @dev is a file or a device not supporting HDIO_GETGEO * ENOMEM Not enough memory to complete the request */ int ntfs_device_sectors_per_track_get(struct ntfs_device *dev) { if (!dev) { errno = EINVAL; return -1; } if (dev->d_sectors_per_track == -1) { if (ntfs_device_get_geo(dev) == -1) return -1; if (dev->d_sectors_per_track == -1) { errno = EINVAL; return -1; } } return dev->d_sectors_per_track; } /** * ntfs_device_sector_size_get - get sector size of a device * @dev: open device * * On success, return the sector size in bytes of the device @dev. * On error return -1 with errno set to the error code. * * The following error codes are defined: * EINVAL Input parameter error * EOPNOTSUPP System does not support BLKSSZGET ioctl * ENOTTY @dev is a file or a device not supporting BLKSSZGET */ int ntfs_device_sector_size_get(struct ntfs_device *dev) { if (!dev) { errno = EINVAL; return -1; } #ifdef BLKSSZGET { int sect_size = 0; if (!dev->d_ops->ioctl(dev, BLKSSZGET, §_size)) { ntfs_log_debug("BLKSSZGET sector size = %d bytes\n", sect_size); return sect_size; } } #elif defined(DIOCGSECTORSIZE) { /* FreeBSD */ size_t sect_size = 0; if (!dev->d_ops->ioctl(dev, DIOCGSECTORSIZE, §_size)) { ntfs_log_debug("DIOCGSECTORSIZE sector size = %d bytes\n", (int) sect_size); return sect_size; } } #elif defined(DKIOCGETBLOCKSIZE) { /* Mac OS X */ uint32_t sect_size = 0; if (!dev->d_ops->ioctl(dev, DKIOCGETBLOCKSIZE, §_size)) { ntfs_log_debug("DKIOCGETBLOCKSIZE sector size = %d bytes\n", (int) sect_size); return sect_size; } } #else errno = EOPNOTSUPP; #endif return -1; } /** * ntfs_device_block_size_set - set block size of a device * @dev: open device * @block_size: block size to set @dev to * * On success, return 0. * On error return -1 with errno set to the error code. * * The following error codes are defined: * EINVAL Input parameter error * EOPNOTSUPP System does not support BLKBSZSET ioctl * ENOTTY @dev is a file or a device not supporting BLKBSZSET */ int ntfs_device_block_size_set(struct ntfs_device *dev, int block_size __attribute__((unused))) { if (!dev) { errno = EINVAL; return -1; } #ifdef BLKBSZSET { size_t s_block_size = block_size; if (!dev->d_ops->ioctl(dev, BLKBSZSET, &s_block_size)) { ntfs_log_debug("Used BLKBSZSET to set block size to " "%d bytes.\n", block_size); return 0; } /* If not a block device, pretend it was successful. */ if (!NDevBlock(dev)) return 0; } #else /* If not a block device, pretend it was successful. */ if (!NDevBlock(dev)) return 0; errno = EOPNOTSUPP; #endif return -1; }