From a34d218e909ba1b0fe3a09c99e15259571f56adc Mon Sep 17 00:00:00 2001 From: "cantab.net!aia21" Date: Mon, 6 Oct 2003 11:38:25 +0000 Subject: [PATCH] merge common functions from disk_io.c into device.c (Logical change 1.188) --- libntfs/device.c | 396 +++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 396 insertions(+) diff --git a/libntfs/device.c b/libntfs/device.c index 1fb956fc..39414392 100644 --- a/libntfs/device.c +++ b/libntfs/device.c @@ -21,12 +21,28 @@ #include "config.h" +#include #include #include #include +#include +#include +#include +#include +#include +#ifdef HAVE_LINUX_FD_H +# include +#endif +#include "types.h" +#include "mst.h" +#include "debug.h" #include "device.h" +#if defined(linux) && defined(_IO) && !defined(BLKGETSIZE) +# define BLKGETSIZE _IO(0x12,96) /* Get device size in 512byte blocks. */ +#endif + /** * ntfs_device_alloc - allocate an ntfs device structure and pre-initialize it * name: name of the device (must be present) @@ -95,3 +111,383 @@ int ntfs_device_free(struct ntfs_device *dev) return 0; } +/** + * 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; + + Dprintf("%s(): Entering for pos 0x%Lx, count 0x%Lx.\n", __FUNCTION__, + pos, count); + if (!b || count < 0 || pos < 0) { + errno = EINVAL; + return -1; + } + if (!count) + return 0; + dops = dev->d_ops; + /* Locate to position. */ + if (dops->seek(dev, pos, SEEK_SET) == (off_t)-1) { + Dprintf("ntfs_pread: device seek to 0x%Lx returned error: " + "%s\n", pos, strerror(errno)); + return -1; + } + /* Read the data. */ + for (total = 0; count; count -= br, total += br) { + br = dops->read(dev, (char*)b + total, count); + /* 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; + struct ntfs_device_operations *dops; + + Dprintf("%s(): Entering for pos 0x%Lx, count 0x%Lx.\n", __FUNCTION__, + pos, count); + if (!b || count < 0 || pos < 0) { + errno = EINVAL; + return -1; + } + if (!count) + return 0; + if (NDevReadOnly(dev)) { + errno = EROFS; + return -1; + } + dops = dev->d_ops; + /* Locate to position. */ + if (dops->seek(dev, pos, SEEK_SET) == (off_t)-1) { + Dprintf("ntfs_pwrite: seek to 0x%Lx returned error: %s\n", + pos, strerror(errno)); + return -1; + } + NDevSetDirty(dev); + /* Write the data. */ + for (total = 0; count; count -= written, total += written) { + written = dops->write(dev, (char*)b + total, count); + /* 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. */ + return written; + } + /* Finally, return the number of bytes written. */ + return total; +} + +/** + * 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_SECTOR_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 interrutped 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, const void *b) +{ + s64 written, i; + + if (count < 0 || bksize % NTFS_SECTOR_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; + return -1; + } + br = ntfs_pread(vol->dev, lcn << vol->cluster_size_bits, + count << vol->cluster_size_bits, b); + if (br < 0) { + Dperror("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; + 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) { + Dperror("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 inline 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. + */ +s64 ntfs_device_size_get(struct ntfs_device *dev, int block_size) +{ + s64 high, low; +#ifdef BLKGETSIZE + long size; + + if (dev->d_ops->ioctl(dev, BLKGETSIZE, &size) >= 0) { + Dprintf("BLKGETSIZE nr 512 byte blocks = %ld (0x%ld)\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) { + Dprintf("FDGETPRM nr 512 byte blocks = %ld (0x%ld)\n", + this_floppy.size, this_floppy.size); + return (s64)this_floppy.size * 512 / 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; +} +