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-rw-r--r--e2fsprogs/ext2fs/unix_io.c707
1 files changed, 707 insertions, 0 deletions
diff --git a/e2fsprogs/ext2fs/unix_io.c b/e2fsprogs/ext2fs/unix_io.c
new file mode 100644
index 000000000..5bc7a6abe
--- /dev/null
+++ b/e2fsprogs/ext2fs/unix_io.c
@@ -0,0 +1,707 @@
+/*
+ * unix_io.c --- This is the Unix (well, really POSIX) implementation
+ * of the I/O manager.
+ *
+ * Implements a one-block write-through cache.
+ *
+ * Includes support for Windows NT support under Cygwin.
+ *
+ * Copyright (C) 1993, 1994, 1995, 1996, 1997, 1998, 1999, 2000, 2001,
+ * 2002 by Theodore Ts'o.
+ *
+ * %Begin-Header%
+ * This file may be redistributed under the terms of the GNU Public
+ * License.
+ * %End-Header%
+ */
+
+#include <stdio.h>
+#include <string.h>
+#if HAVE_UNISTD_H
+#include <unistd.h>
+#endif
+#if HAVE_ERRNO_H
+#include <errno.h>
+#endif
+#include <fcntl.h>
+#include <time.h>
+#ifdef __linux__
+#include <sys/utsname.h>
+#endif
+#if HAVE_SYS_STAT_H
+#include <sys/stat.h>
+#endif
+#if HAVE_SYS_TYPES_H
+#include <sys/types.h>
+#endif
+#if HAVE_SYS_RESOURCE_H
+#include <sys/resource.h>
+#endif
+
+#include "ext2_fs.h"
+#include "ext2fs.h"
+
+/*
+ * For checking structure magic numbers...
+ */
+
+#define EXT2_CHECK_MAGIC(struct, code) \
+ if ((struct)->magic != (code)) return (code)
+
+struct unix_cache {
+ char *buf;
+ unsigned long block;
+ int access_time;
+ unsigned dirty:1;
+ unsigned in_use:1;
+};
+
+#define CACHE_SIZE 8
+#define WRITE_DIRECT_SIZE 4 /* Must be smaller than CACHE_SIZE */
+#define READ_DIRECT_SIZE 4 /* Should be smaller than CACHE_SIZE */
+
+struct unix_private_data {
+ int magic;
+ int dev;
+ int flags;
+ int access_time;
+ ext2_loff_t offset;
+ struct unix_cache cache[CACHE_SIZE];
+};
+
+static errcode_t unix_open(const char *name, int flags, io_channel *channel);
+static errcode_t unix_close(io_channel channel);
+static errcode_t unix_set_blksize(io_channel channel, int blksize);
+static errcode_t unix_read_blk(io_channel channel, unsigned long block,
+ int count, void *data);
+static errcode_t unix_write_blk(io_channel channel, unsigned long block,
+ int count, const void *data);
+static errcode_t unix_flush(io_channel channel);
+static errcode_t unix_write_byte(io_channel channel, unsigned long offset,
+ int size, const void *data);
+static errcode_t unix_set_option(io_channel channel, const char *option,
+ const char *arg);
+
+static void reuse_cache(io_channel channel, struct unix_private_data *data,
+ struct unix_cache *cache, unsigned long block);
+
+/* __FreeBSD_kernel__ is defined by GNU/kFreeBSD - the FreeBSD kernel
+ * does not know buffered block devices - everything is raw. */
+#if defined(__CYGWIN__) || defined(__FreeBSD__) || defined(__FreeBSD_kernel__)
+#define NEED_BOUNCE_BUFFER
+#else
+#undef NEED_BOUNCE_BUFFER
+#endif
+
+static struct struct_io_manager struct_unix_manager = {
+ EXT2_ET_MAGIC_IO_MANAGER,
+ "Unix I/O Manager",
+ unix_open,
+ unix_close,
+ unix_set_blksize,
+ unix_read_blk,
+ unix_write_blk,
+ unix_flush,
+#ifdef NEED_BOUNCE_BUFFER
+ 0,
+#else
+ unix_write_byte,
+#endif
+ unix_set_option
+};
+
+io_manager unix_io_manager = &struct_unix_manager;
+
+/*
+ * Here are the raw I/O functions
+ */
+#ifndef NEED_BOUNCE_BUFFER
+static errcode_t raw_read_blk(io_channel channel,
+ struct unix_private_data *data,
+ unsigned long block,
+ int count, void *buf)
+{
+ errcode_t retval;
+ ssize_t size;
+ ext2_loff_t location;
+ int actual = 0;
+
+ size = (count < 0) ? -count : count * channel->block_size;
+ location = ((ext2_loff_t) block * channel->block_size) + data->offset;
+ if (ext2fs_llseek(data->dev, location, SEEK_SET) != location) {
+ retval = errno ? errno : EXT2_ET_LLSEEK_FAILED;
+ goto error_out;
+ }
+ actual = read(data->dev, buf, size);
+ if (actual != size) {
+ if (actual < 0)
+ actual = 0;
+ retval = EXT2_ET_SHORT_READ;
+ goto error_out;
+ }
+ return 0;
+
+error_out:
+ memset((char *) buf+actual, 0, size-actual);
+ if (channel->read_error)
+ retval = (channel->read_error)(channel, block, count, buf,
+ size, actual, retval);
+ return retval;
+}
+#else /* NEED_BOUNCE_BUFFER */
+/*
+ * Windows and FreeBSD block devices only allow sector alignment IO in offset and size
+ */
+static errcode_t raw_read_blk(io_channel channel,
+ struct unix_private_data *data,
+ unsigned long block,
+ int count, void *buf)
+{
+ errcode_t retval;
+ size_t size, alignsize, fragment;
+ ext2_loff_t location;
+ int total = 0, actual;
+#define BLOCKALIGN 512
+ char sector[BLOCKALIGN];
+
+ size = (count < 0) ? -count : count * channel->block_size;
+ location = ((ext2_loff_t) block * channel->block_size) + data->offset;
+#ifdef DEBUG
+ printf("count=%d, size=%d, block=%d, blk_size=%d, location=%lx\n",
+ count, size, block, channel->block_size, location);
+#endif
+ if (ext2fs_llseek(data->dev, location, SEEK_SET) != location) {
+ retval = errno ? errno : EXT2_ET_LLSEEK_FAILED;
+ goto error_out;
+ }
+ fragment = size % BLOCKALIGN;
+ alignsize = size - fragment;
+ if (alignsize) {
+ actual = read(data->dev, buf, alignsize);
+ if (actual != alignsize)
+ goto short_read;
+ }
+ if (fragment) {
+ actual = read(data->dev, sector, BLOCKALIGN);
+ if (actual != BLOCKALIGN)
+ goto short_read;
+ memcpy(buf+alignsize, sector, fragment);
+ }
+ return 0;
+
+short_read:
+ if (actual>0)
+ total += actual;
+ retval = EXT2_ET_SHORT_READ;
+
+error_out:
+ memset((char *) buf+total, 0, size-actual);
+ if (channel->read_error)
+ retval = (channel->read_error)(channel, block, count, buf,
+ size, actual, retval);
+ return retval;
+}
+#endif
+
+static errcode_t raw_write_blk(io_channel channel,
+ struct unix_private_data *data,
+ unsigned long block,
+ int count, const void *buf)
+{
+ ssize_t size;
+ ext2_loff_t location;
+ int actual = 0;
+ errcode_t retval;
+
+ if (count == 1)
+ size = channel->block_size;
+ else {
+ if (count < 0)
+ size = -count;
+ else
+ size = count * channel->block_size;
+ }
+
+ location = ((ext2_loff_t) block * channel->block_size) + data->offset;
+ if (ext2fs_llseek(data->dev, location, SEEK_SET) != location) {
+ retval = errno ? errno : EXT2_ET_LLSEEK_FAILED;
+ goto error_out;
+ }
+
+ actual = write(data->dev, buf, size);
+ if (actual != size) {
+ retval = EXT2_ET_SHORT_WRITE;
+ goto error_out;
+ }
+ return 0;
+
+error_out:
+ if (channel->write_error)
+ retval = (channel->write_error)(channel, block, count, buf,
+ size, actual, retval);
+ return retval;
+}
+
+
+/*
+ * Here we implement the cache functions
+ */
+
+/* Allocate the cache buffers */
+static errcode_t alloc_cache(io_channel channel,
+ struct unix_private_data *data)
+{
+ errcode_t retval;
+ struct unix_cache *cache;
+ int i;
+
+ data->access_time = 0;
+ for (i=0, cache = data->cache; i < CACHE_SIZE; i++, cache++) {
+ cache->block = 0;
+ cache->access_time = 0;
+ cache->dirty = 0;
+ cache->in_use = 0;
+ if ((retval = ext2fs_get_mem(channel->block_size,
+ &cache->buf)))
+ return retval;
+ }
+ return 0;
+}
+
+/* Free the cache buffers */
+static void free_cache(struct unix_private_data *data)
+{
+ struct unix_cache *cache;
+ int i;
+
+ data->access_time = 0;
+ for (i=0, cache = data->cache; i < CACHE_SIZE; i++, cache++) {
+ cache->block = 0;
+ cache->access_time = 0;
+ cache->dirty = 0;
+ cache->in_use = 0;
+ if (cache->buf)
+ ext2fs_free_mem(&cache->buf);
+ cache->buf = 0;
+ }
+}
+
+#ifndef NO_IO_CACHE
+/*
+ * Try to find a block in the cache. If the block is not found, and
+ * eldest is a non-zero pointer, then fill in eldest with the cache
+ * entry to that should be reused.
+ */
+static struct unix_cache *find_cached_block(struct unix_private_data *data,
+ unsigned long block,
+ struct unix_cache **eldest)
+{
+ struct unix_cache *cache, *unused_cache, *oldest_cache;
+ int i;
+
+ unused_cache = oldest_cache = 0;
+ for (i=0, cache = data->cache; i < CACHE_SIZE; i++, cache++) {
+ if (!cache->in_use) {
+ if (!unused_cache)
+ unused_cache = cache;
+ continue;
+ }
+ if (cache->block == block) {
+ cache->access_time = ++data->access_time;
+ return cache;
+ }
+ if (!oldest_cache ||
+ (cache->access_time < oldest_cache->access_time))
+ oldest_cache = cache;
+ }
+ if (eldest)
+ *eldest = (unused_cache) ? unused_cache : oldest_cache;
+ return 0;
+}
+
+/*
+ * Reuse a particular cache entry for another block.
+ */
+static void reuse_cache(io_channel channel, struct unix_private_data *data,
+ struct unix_cache *cache, unsigned long block)
+{
+ if (cache->dirty && cache->in_use)
+ raw_write_blk(channel, data, cache->block, 1, cache->buf);
+
+ cache->in_use = 1;
+ cache->dirty = 0;
+ cache->block = block;
+ cache->access_time = ++data->access_time;
+}
+
+/*
+ * Flush all of the blocks in the cache
+ */
+static errcode_t flush_cached_blocks(io_channel channel,
+ struct unix_private_data *data,
+ int invalidate)
+
+{
+ struct unix_cache *cache;
+ errcode_t retval, retval2;
+ int i;
+
+ retval2 = 0;
+ for (i=0, cache = data->cache; i < CACHE_SIZE; i++, cache++) {
+ if (!cache->in_use)
+ continue;
+
+ if (invalidate)
+ cache->in_use = 0;
+
+ if (!cache->dirty)
+ continue;
+
+ retval = raw_write_blk(channel, data,
+ cache->block, 1, cache->buf);
+ if (retval)
+ retval2 = retval;
+ else
+ cache->dirty = 0;
+ }
+ return retval2;
+}
+#endif /* NO_IO_CACHE */
+
+static errcode_t unix_open(const char *name, int flags, io_channel *channel)
+{
+ io_channel io = NULL;
+ struct unix_private_data *data = NULL;
+ errcode_t retval;
+ int open_flags;
+ struct stat st;
+#ifdef __linux__
+ struct utsname ut;
+#endif
+
+ if (name == 0)
+ return EXT2_ET_BAD_DEVICE_NAME;
+ retval = ext2fs_get_mem(sizeof(struct struct_io_channel), &io);
+ if (retval)
+ return retval;
+ memset(io, 0, sizeof(struct struct_io_channel));
+ io->magic = EXT2_ET_MAGIC_IO_CHANNEL;
+ retval = ext2fs_get_mem(sizeof(struct unix_private_data), &data);
+ if (retval)
+ goto cleanup;
+
+ io->manager = unix_io_manager;
+ retval = ext2fs_get_mem(strlen(name)+1, &io->name);
+ if (retval)
+ goto cleanup;
+
+ strcpy(io->name, name);
+ io->private_data = data;
+ io->block_size = 1024;
+ io->read_error = 0;
+ io->write_error = 0;
+ io->refcount = 1;
+
+ memset(data, 0, sizeof(struct unix_private_data));
+ data->magic = EXT2_ET_MAGIC_UNIX_IO_CHANNEL;
+
+ if ((retval = alloc_cache(io, data)))
+ goto cleanup;
+
+ open_flags = (flags & IO_FLAG_RW) ? O_RDWR : O_RDONLY;
+#ifdef CONFIG_LFS
+ data->dev = open64(io->name, open_flags);
+#else
+ data->dev = open(io->name, open_flags);
+#endif
+ if (data->dev < 0) {
+ retval = errno;
+ goto cleanup;
+ }
+
+#ifdef __linux__
+#undef RLIM_INFINITY
+#if (defined(__alpha__) || ((defined(__sparc__) || defined(__mips__)) && (SIZEOF_LONG == 4)))
+#define RLIM_INFINITY ((unsigned long)(~0UL>>1))
+#else
+#define RLIM_INFINITY (~0UL)
+#endif
+ /*
+ * Work around a bug in 2.4.10-2.4.18 kernels where writes to
+ * block devices are wrongly getting hit by the filesize
+ * limit. This workaround isn't perfect, since it won't work
+ * if glibc wasn't built against 2.2 header files. (Sigh.)
+ *
+ */
+ if ((flags & IO_FLAG_RW) &&
+ (uname(&ut) == 0) &&
+ ((ut.release[0] == '2') && (ut.release[1] == '.') &&
+ (ut.release[2] == '4') && (ut.release[3] == '.') &&
+ (ut.release[4] == '1') && (ut.release[5] >= '0') &&
+ (ut.release[5] < '8')) &&
+ (fstat(data->dev, &st) == 0) &&
+ (S_ISBLK(st.st_mode))) {
+ struct rlimit rlim;
+
+ rlim.rlim_cur = rlim.rlim_max = (unsigned long) RLIM_INFINITY;
+ setrlimit(RLIMIT_FSIZE, &rlim);
+ getrlimit(RLIMIT_FSIZE, &rlim);
+ if (((unsigned long) rlim.rlim_cur) <
+ ((unsigned long) rlim.rlim_max)) {
+ rlim.rlim_cur = rlim.rlim_max;
+ setrlimit(RLIMIT_FSIZE, &rlim);
+ }
+ }
+#endif
+ *channel = io;
+ return 0;
+
+cleanup:
+ if (data) {
+ free_cache(data);
+ ext2fs_free_mem(&data);
+ }
+ if (io)
+ ext2fs_free_mem(&io);
+ return retval;
+}
+
+static errcode_t unix_close(io_channel channel)
+{
+ struct unix_private_data *data;
+ errcode_t retval = 0;
+
+ EXT2_CHECK_MAGIC(channel, EXT2_ET_MAGIC_IO_CHANNEL);
+ data = (struct unix_private_data *) channel->private_data;
+ EXT2_CHECK_MAGIC(data, EXT2_ET_MAGIC_UNIX_IO_CHANNEL);
+
+ if (--channel->refcount > 0)
+ return 0;
+
+#ifndef NO_IO_CACHE
+ retval = flush_cached_blocks(channel, data, 0);
+#endif
+
+ if (close(data->dev) < 0)
+ retval = errno;
+ free_cache(data);
+
+ ext2fs_free_mem(&channel->private_data);
+ if (channel->name)
+ ext2fs_free_mem(&channel->name);
+ ext2fs_free_mem(&channel);
+ return retval;
+}
+
+static errcode_t unix_set_blksize(io_channel channel, int blksize)
+{
+ struct unix_private_data *data;
+ errcode_t retval;
+
+ EXT2_CHECK_MAGIC(channel, EXT2_ET_MAGIC_IO_CHANNEL);
+ data = (struct unix_private_data *) channel->private_data;
+ EXT2_CHECK_MAGIC(data, EXT2_ET_MAGIC_UNIX_IO_CHANNEL);
+
+ if (channel->block_size != blksize) {
+#ifndef NO_IO_CACHE
+ if ((retval = flush_cached_blocks(channel, data, 0)))
+ return retval;
+#endif
+
+ channel->block_size = blksize;
+ free_cache(data);
+ if ((retval = alloc_cache(channel, data)))
+ return retval;
+ }
+ return 0;
+}
+
+
+static errcode_t unix_read_blk(io_channel channel, unsigned long block,
+ int count, void *buf)
+{
+ struct unix_private_data *data;
+ struct unix_cache *cache, *reuse[READ_DIRECT_SIZE];
+ errcode_t retval;
+ char *cp;
+ int i, j;
+
+ EXT2_CHECK_MAGIC(channel, EXT2_ET_MAGIC_IO_CHANNEL);
+ data = (struct unix_private_data *) channel->private_data;
+ EXT2_CHECK_MAGIC(data, EXT2_ET_MAGIC_UNIX_IO_CHANNEL);
+
+#ifdef NO_IO_CACHE
+ return raw_read_blk(channel, data, block, count, buf);
+#else
+ /*
+ * If we're doing an odd-sized read or a very large read,
+ * flush out the cache and then do a direct read.
+ */
+ if (count < 0 || count > WRITE_DIRECT_SIZE) {
+ if ((retval = flush_cached_blocks(channel, data, 0)))
+ return retval;
+ return raw_read_blk(channel, data, block, count, buf);
+ }
+
+ cp = buf;
+ while (count > 0) {
+ /* If it's in the cache, use it! */
+ if ((cache = find_cached_block(data, block, &reuse[0]))) {
+#ifdef DEBUG
+ printf("Using cached block %d\n", block);
+#endif
+ memcpy(cp, cache->buf, channel->block_size);
+ count--;
+ block++;
+ cp += channel->block_size;
+ continue;
+ }
+ /*
+ * Find the number of uncached blocks so we can do a
+ * single read request
+ */
+ for (i=1; i < count; i++)
+ if (find_cached_block(data, block+i, &reuse[i]))
+ break;
+#ifdef DEBUG
+ printf("Reading %d blocks starting at %d\n", i, block);
+#endif
+ if ((retval = raw_read_blk(channel, data, block, i, cp)))
+ return retval;
+
+ /* Save the results in the cache */
+ for (j=0; j < i; j++) {
+ count--;
+ cache = reuse[j];
+ reuse_cache(channel, data, cache, block++);
+ memcpy(cache->buf, cp, channel->block_size);
+ cp += channel->block_size;
+ }
+ }
+ return 0;
+#endif /* NO_IO_CACHE */
+}
+
+static errcode_t unix_write_blk(io_channel channel, unsigned long block,
+ int count, const void *buf)
+{
+ struct unix_private_data *data;
+ struct unix_cache *cache, *reuse;
+ errcode_t retval = 0;
+ const char *cp;
+ int writethrough;
+
+ EXT2_CHECK_MAGIC(channel, EXT2_ET_MAGIC_IO_CHANNEL);
+ data = (struct unix_private_data *) channel->private_data;
+ EXT2_CHECK_MAGIC(data, EXT2_ET_MAGIC_UNIX_IO_CHANNEL);
+
+#ifdef NO_IO_CACHE
+ return raw_write_blk(channel, data, block, count, buf);
+#else
+ /*
+ * If we're doing an odd-sized write or a very large write,
+ * flush out the cache completely and then do a direct write.
+ */
+ if (count < 0 || count > WRITE_DIRECT_SIZE) {
+ if ((retval = flush_cached_blocks(channel, data, 1)))
+ return retval;
+ return raw_write_blk(channel, data, block, count, buf);
+ }
+
+ /*
+ * For a moderate-sized multi-block write, first force a write
+ * if we're in write-through cache mode, and then fill the
+ * cache with the blocks.
+ */
+ writethrough = channel->flags & CHANNEL_FLAGS_WRITETHROUGH;
+ if (writethrough)
+ retval = raw_write_blk(channel, data, block, count, buf);
+
+ cp = buf;
+ while (count > 0) {
+ cache = find_cached_block(data, block, &reuse);
+ if (!cache) {
+ cache = reuse;
+ reuse_cache(channel, data, cache, block);
+ }
+ memcpy(cache->buf, cp, channel->block_size);
+ cache->dirty = !writethrough;
+ count--;
+ block++;
+ cp += channel->block_size;
+ }
+ return retval;
+#endif /* NO_IO_CACHE */
+}
+
+static errcode_t unix_write_byte(io_channel channel, unsigned long offset,
+ int size, const void *buf)
+{
+ struct unix_private_data *data;
+ errcode_t retval = 0;
+ ssize_t actual;
+
+ EXT2_CHECK_MAGIC(channel, EXT2_ET_MAGIC_IO_CHANNEL);
+ data = (struct unix_private_data *) channel->private_data;
+ EXT2_CHECK_MAGIC(data, EXT2_ET_MAGIC_UNIX_IO_CHANNEL);
+
+#ifndef NO_IO_CACHE
+ /*
+ * Flush out the cache completely
+ */
+ if ((retval = flush_cached_blocks(channel, data, 1)))
+ return retval;
+#endif
+
+ if (lseek(data->dev, offset + data->offset, SEEK_SET) < 0)
+ return errno;
+
+ actual = write(data->dev, buf, size);
+ if (actual != size)
+ return EXT2_ET_SHORT_WRITE;
+
+ return 0;
+}
+
+/*
+ * Flush data buffers to disk.
+ */
+static errcode_t unix_flush(io_channel channel)
+{
+ struct unix_private_data *data;
+ errcode_t retval = 0;
+
+ EXT2_CHECK_MAGIC(channel, EXT2_ET_MAGIC_IO_CHANNEL);
+ data = (struct unix_private_data *) channel->private_data;
+ EXT2_CHECK_MAGIC(data, EXT2_ET_MAGIC_UNIX_IO_CHANNEL);
+
+#ifndef NO_IO_CACHE
+ retval = flush_cached_blocks(channel, data, 0);
+#endif
+ fsync(data->dev);
+ return retval;
+}
+
+static errcode_t unix_set_option(io_channel channel, const char *option,
+ const char *arg)
+{
+ struct unix_private_data *data;
+ unsigned long tmp;
+ char *end;
+
+ EXT2_CHECK_MAGIC(channel, EXT2_ET_MAGIC_IO_CHANNEL);
+ data = (struct unix_private_data *) channel->private_data;
+ EXT2_CHECK_MAGIC(data, EXT2_ET_MAGIC_UNIX_IO_CHANNEL);
+
+ if (!strcmp(option, "offset")) {
+ if (!arg)
+ return EXT2_ET_INVALID_ARGUMENT;
+
+ tmp = strtoul(arg, &end, 0);
+ if (*end)
+ return EXT2_ET_INVALID_ARGUMENT;
+ data->offset = tmp;
+ return 0;
+ }
+ return EXT2_ET_INVALID_ARGUMENT;
+}