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-rw-r--r--lib/ext2fs/fileio.c666
1 files changed, 666 insertions, 0 deletions
diff --git a/lib/ext2fs/fileio.c b/lib/ext2fs/fileio.c
new file mode 100644
index 0000000..818f7f0
--- /dev/null
+++ b/lib/ext2fs/fileio.c
@@ -0,0 +1,666 @@
+/*
+ * fileio.c --- Simple file I/O routines
+ *
+ * Copyright (C) 1997 Theodore Ts'o.
+ *
+ * %Begin-Header%
+ * This file may be redistributed under the terms of the GNU Library
+ * General Public License, version 2.
+ * %End-Header%
+ */
+
+#include "config.h"
+#include <stdio.h>
+#include <string.h>
+#if HAVE_UNISTD_H
+#include <unistd.h>
+#endif
+
+#include "ext2_fs.h"
+#include "ext2fs.h"
+#include "ext2fsP.h"
+
+struct ext2_file {
+ errcode_t magic;
+ ext2_filsys fs;
+ ext2_ino_t ino;
+ struct ext2_inode inode;
+ int flags;
+ __u64 pos;
+ blk64_t blockno;
+ blk64_t physblock;
+ char *buf;
+};
+
+struct block_entry {
+ blk64_t physblock;
+ unsigned char sha[EXT2FS_SHA512_LENGTH];
+};
+typedef struct block_entry *block_entry_t;
+
+#define BMAP_BUFFER (file->buf + fs->blocksize)
+
+errcode_t ext2fs_file_open2(ext2_filsys fs, ext2_ino_t ino,
+ struct ext2_inode *inode,
+ int flags, ext2_file_t *ret)
+{
+ ext2_file_t file;
+ errcode_t retval;
+
+ /*
+ * Don't let caller create or open a file for writing if the
+ * filesystem is read-only.
+ */
+ if ((flags & (EXT2_FILE_WRITE | EXT2_FILE_CREATE)) &&
+ !(fs->flags & EXT2_FLAG_RW))
+ return EXT2_ET_RO_FILSYS;
+
+ retval = ext2fs_get_mem(sizeof(struct ext2_file), &file);
+ if (retval)
+ return retval;
+
+ memset(file, 0, sizeof(struct ext2_file));
+ file->magic = EXT2_ET_MAGIC_EXT2_FILE;
+ file->fs = fs;
+ file->ino = ino;
+ file->flags = flags & EXT2_FILE_MASK;
+
+ if (inode) {
+ memcpy(&file->inode, inode, sizeof(struct ext2_inode));
+ } else {
+ retval = ext2fs_read_inode(fs, ino, &file->inode);
+ if (retval)
+ goto fail;
+ }
+
+ retval = ext2fs_get_array(3, fs->blocksize, &file->buf);
+ if (retval)
+ goto fail;
+
+ *ret = file;
+ return 0;
+
+fail:
+ if (file->buf)
+ ext2fs_free_mem(&file->buf);
+ ext2fs_free_mem(&file);
+ return retval;
+}
+
+errcode_t ext2fs_file_open(ext2_filsys fs, ext2_ino_t ino,
+ int flags, ext2_file_t *ret)
+{
+ return ext2fs_file_open2(fs, ino, NULL, flags, ret);
+}
+
+/*
+ * This function returns the filesystem handle of a file from the structure
+ */
+ext2_filsys ext2fs_file_get_fs(ext2_file_t file)
+{
+ if (file->magic != EXT2_ET_MAGIC_EXT2_FILE)
+ return 0;
+ return file->fs;
+}
+
+/*
+ * This function returns the pointer to the inode of a file from the structure
+ */
+struct ext2_inode *ext2fs_file_get_inode(ext2_file_t file)
+{
+ if (file->magic != EXT2_ET_MAGIC_EXT2_FILE)
+ return NULL;
+ return &file->inode;
+}
+
+/* This function returns the inode number from the structure */
+ext2_ino_t ext2fs_file_get_inode_num(ext2_file_t file)
+{
+ if (file->magic != EXT2_ET_MAGIC_EXT2_FILE)
+ return 0;
+ return file->ino;
+}
+
+/*
+ * This function flushes the dirty block buffer out to disk if
+ * necessary.
+ */
+errcode_t ext2fs_file_flush(ext2_file_t file)
+{
+ errcode_t retval;
+ ext2_filsys fs;
+ int ret_flags;
+ blk64_t dontcare;
+
+ EXT2_CHECK_MAGIC(file, EXT2_ET_MAGIC_EXT2_FILE);
+ fs = file->fs;
+
+ if (!(file->flags & EXT2_FILE_BUF_VALID) ||
+ !(file->flags & EXT2_FILE_BUF_DIRTY))
+ return 0;
+
+ /* Is this an uninit block? */
+ if (file->physblock && file->inode.i_flags & EXT4_EXTENTS_FL) {
+ retval = ext2fs_bmap2(fs, file->ino, &file->inode, BMAP_BUFFER,
+ 0, file->blockno, &ret_flags, &dontcare);
+ if (retval)
+ return retval;
+ if (ret_flags & BMAP_RET_UNINIT) {
+ retval = ext2fs_bmap2(fs, file->ino, &file->inode,
+ BMAP_BUFFER, BMAP_SET,
+ file->blockno, 0,
+ &file->physblock);
+ if (retval)
+ return retval;
+ }
+ }
+
+ /*
+ * OK, the physical block hasn't been allocated yet.
+ * Allocate it.
+ */
+ if (!file->physblock) {
+ retval = ext2fs_bmap2(fs, file->ino, &file->inode,
+ BMAP_BUFFER, file->ino ? BMAP_ALLOC : 0,
+ file->blockno, 0, &file->physblock);
+ if (retval)
+ return retval;
+ }
+
+ retval = io_channel_write_blk64(fs->io, file->physblock, 1, file->buf);
+ if (retval)
+ return retval;
+
+ file->flags &= ~EXT2_FILE_BUF_DIRTY;
+
+ return retval;
+}
+
+/*
+ * This function synchronizes the file's block buffer and the current
+ * file position, possibly invalidating block buffer if necessary
+ */
+static errcode_t sync_buffer_position(ext2_file_t file)
+{
+ blk64_t b;
+ errcode_t retval;
+
+ b = file->pos / file->fs->blocksize;
+ if (b != file->blockno) {
+ retval = ext2fs_file_flush(file);
+ if (retval)
+ return retval;
+ file->flags &= ~EXT2_FILE_BUF_VALID;
+ }
+ file->blockno = b;
+ return 0;
+}
+
+/*
+ * This function loads the file's block buffer with valid data from
+ * the disk as necessary.
+ *
+ * If dontfill is true, then skip initializing the buffer since we're
+ * going to be replacing its entire contents anyway. If set, then the
+ * function basically only sets file->physblock and EXT2_FILE_BUF_VALID
+ */
+#define DONTFILL 1
+static errcode_t load_buffer(ext2_file_t file, int dontfill)
+{
+ ext2_filsys fs = file->fs;
+ errcode_t retval;
+ int ret_flags;
+
+ if (!(file->flags & EXT2_FILE_BUF_VALID)) {
+ retval = ext2fs_bmap2(fs, file->ino, &file->inode,
+ BMAP_BUFFER, 0, file->blockno, &ret_flags,
+ &file->physblock);
+ if (retval)
+ return retval;
+ if (!dontfill) {
+ if (file->physblock &&
+ !(ret_flags & BMAP_RET_UNINIT)) {
+ retval = io_channel_read_blk64(fs->io,
+ file->physblock,
+ 1, file->buf);
+ if (retval)
+ return retval;
+ } else
+ memset(file->buf, 0, fs->blocksize);
+ }
+ file->flags |= EXT2_FILE_BUF_VALID;
+ }
+ return 0;
+}
+
+
+errcode_t ext2fs_file_close(ext2_file_t file)
+{
+ errcode_t retval;
+
+ EXT2_CHECK_MAGIC(file, EXT2_ET_MAGIC_EXT2_FILE);
+
+ retval = ext2fs_file_flush(file);
+
+ if (file->buf)
+ ext2fs_free_mem(&file->buf);
+ ext2fs_free_mem(&file);
+
+ return retval;
+}
+
+
+static errcode_t
+ext2fs_file_read_inline_data(ext2_file_t file, void *buf,
+ unsigned int wanted, unsigned int *got)
+{
+ ext2_filsys fs;
+ errcode_t retval;
+ unsigned int count = 0;
+ size_t size;
+
+ fs = file->fs;
+ retval = ext2fs_inline_data_get(fs, file->ino, &file->inode,
+ file->buf, &size);
+ if (retval)
+ return retval;
+
+ if (file->pos >= size)
+ goto out;
+
+ count = size - file->pos;
+ if (count > wanted)
+ count = wanted;
+ memcpy(buf, file->buf + file->pos, count);
+ file->pos += count;
+ buf = (char *) buf + count;
+
+out:
+ if (got)
+ *got = count;
+ return retval;
+}
+
+
+errcode_t ext2fs_file_read(ext2_file_t file, void *buf,
+ unsigned int wanted, unsigned int *got)
+{
+ ext2_filsys fs;
+ errcode_t retval = 0;
+ unsigned int start, c, count = 0;
+ __u64 left;
+ char *ptr = (char *) buf;
+
+ EXT2_CHECK_MAGIC(file, EXT2_ET_MAGIC_EXT2_FILE);
+ fs = file->fs;
+
+ /* If an inode has inline data, things get complicated. */
+ if (file->inode.i_flags & EXT4_INLINE_DATA_FL)
+ return ext2fs_file_read_inline_data(file, buf, wanted, got);
+
+ while ((file->pos < EXT2_I_SIZE(&file->inode)) && (wanted > 0)) {
+ retval = sync_buffer_position(file);
+ if (retval)
+ goto fail;
+ retval = load_buffer(file, 0);
+ if (retval)
+ goto fail;
+
+ start = file->pos % fs->blocksize;
+ c = fs->blocksize - start;
+ if (c > wanted)
+ c = wanted;
+ left = EXT2_I_SIZE(&file->inode) - file->pos ;
+ if (c > left)
+ c = left;
+
+ memcpy(ptr, file->buf+start, c);
+ file->pos += c;
+ ptr += c;
+ count += c;
+ wanted -= c;
+ }
+
+fail:
+ if (got)
+ *got = count;
+ return retval;
+}
+
+
+static errcode_t
+ext2fs_file_write_inline_data(ext2_file_t file, const void *buf,
+ unsigned int nbytes, unsigned int *written)
+{
+ ext2_filsys fs;
+ errcode_t retval;
+ unsigned int count = 0;
+ size_t size;
+
+ fs = file->fs;
+ retval = ext2fs_inline_data_get(fs, file->ino, &file->inode,
+ file->buf, &size);
+ if (retval)
+ return retval;
+
+ if (file->pos < size) {
+ count = nbytes - file->pos;
+ memcpy(file->buf + file->pos, buf, count);
+
+ retval = ext2fs_inline_data_set(fs, file->ino, &file->inode,
+ file->buf, count);
+ if (retval == EXT2_ET_INLINE_DATA_NO_SPACE)
+ goto expand;
+ if (retval)
+ return retval;
+
+ file->pos += count;
+
+ /* Update inode size */
+ if (count != 0 && EXT2_I_SIZE(&file->inode) < file->pos) {
+ errcode_t rc;
+
+ rc = ext2fs_file_set_size2(file, file->pos);
+ if (retval == 0)
+ retval = rc;
+ }
+
+ if (written)
+ *written = count;
+ return 0;
+ }
+
+expand:
+ retval = ext2fs_inline_data_expand(fs, file->ino);
+ if (retval)
+ return retval;
+ /*
+ * reload inode and return no space error
+ *
+ * XXX: file->inode could be copied from the outside
+ * in ext2fs_file_open2(). We have no way to modify
+ * the outside inode.
+ */
+ retval = ext2fs_read_inode(fs, file->ino, &file->inode);
+ if (retval)
+ return retval;
+ return EXT2_ET_INLINE_DATA_NO_SPACE;
+}
+
+
+errcode_t ext2fs_file_write(ext2_file_t file, const void *buf,
+ unsigned int nbytes, unsigned int *written)
+{
+ ext2_filsys fs;
+ errcode_t retval = 0;
+ unsigned int start, c, count = 0;
+ const char *ptr = (const char *) buf;
+ block_entry_t new_block = NULL, old_block = NULL;
+ int bmap_flags = 0;
+
+ EXT2_CHECK_MAGIC(file, EXT2_ET_MAGIC_EXT2_FILE);
+ fs = file->fs;
+
+ if (!(file->flags & EXT2_FILE_WRITE))
+ return EXT2_ET_FILE_RO;
+
+ /* If an inode has inline data, things get complicated. */
+ if (file->inode.i_flags & EXT4_INLINE_DATA_FL) {
+ retval = ext2fs_file_write_inline_data(file, buf, nbytes,
+ written);
+ if (retval != EXT2_ET_INLINE_DATA_NO_SPACE)
+ return retval;
+ /* fall through to read data from the block */
+ retval = 0;
+ }
+
+ while (nbytes > 0) {
+ retval = sync_buffer_position(file);
+ if (retval)
+ goto fail;
+
+ start = file->pos % fs->blocksize;
+ c = fs->blocksize - start;
+ if (c > nbytes)
+ c = nbytes;
+
+ /*
+ * We only need to do a read-modify-update cycle if
+ * we're doing a partial write.
+ */
+ retval = load_buffer(file, (c == fs->blocksize));
+ if (retval)
+ goto fail;
+
+ file->flags |= EXT2_FILE_BUF_DIRTY;
+ memcpy(file->buf+start, ptr, c);
+
+ /*
+ * OK, the physical block hasn't been allocated yet.
+ * Allocate it.
+ */
+ if (!file->physblock) {
+ bmap_flags = (file->ino ? BMAP_ALLOC : 0);
+ if (fs->flags & EXT2_FLAG_SHARE_DUP) {
+ new_block = calloc(1, sizeof(*new_block));
+ if (!new_block) {
+ retval = EXT2_ET_NO_MEMORY;
+ goto fail;
+ }
+ ext2fs_sha512((const unsigned char*)file->buf,
+ fs->blocksize, new_block->sha);
+ old_block = ext2fs_hashmap_lookup(
+ fs->block_sha_map,
+ new_block->sha,
+ sizeof(new_block->sha));
+ }
+
+ if (old_block) {
+ file->physblock = old_block->physblock;
+ bmap_flags |= BMAP_SET;
+ free(new_block);
+ new_block = NULL;
+ }
+
+ retval = ext2fs_bmap2(fs, file->ino, &file->inode,
+ BMAP_BUFFER,
+ bmap_flags,
+ file->blockno, 0,
+ &file->physblock);
+ if (retval) {
+ free(new_block);
+ new_block = NULL;
+ goto fail;
+ }
+
+ if (new_block) {
+ new_block->physblock = file->physblock;
+ int ret = ext2fs_hashmap_add(fs->block_sha_map,
+ new_block, new_block->sha,
+ sizeof(new_block->sha));
+ if (ret) {
+ retval = EXT2_ET_NO_MEMORY;
+ free(new_block);
+ goto fail;
+ }
+ }
+
+ if (bmap_flags & BMAP_SET) {
+ ext2fs_iblk_add_blocks(fs, &file->inode, 1);
+ ext2fs_write_inode(fs, file->ino, &file->inode);
+ }
+ }
+
+ file->pos += c;
+ ptr += c;
+ count += c;
+ nbytes -= c;
+ }
+
+fail:
+ /* Update inode size */
+ if (count != 0 && EXT2_I_SIZE(&file->inode) < file->pos) {
+ errcode_t rc;
+
+ rc = ext2fs_file_set_size2(file, file->pos);
+ if (retval == 0)
+ retval = rc;
+ }
+
+ if (written)
+ *written = count;
+ return retval;
+}
+
+errcode_t ext2fs_file_llseek(ext2_file_t file, __u64 offset,
+ int whence, __u64 *ret_pos)
+{
+ EXT2_CHECK_MAGIC(file, EXT2_ET_MAGIC_EXT2_FILE);
+
+ if (whence == EXT2_SEEK_SET)
+ file->pos = offset;
+ else if (whence == EXT2_SEEK_CUR)
+ file->pos += offset;
+ else if (whence == EXT2_SEEK_END)
+ file->pos = EXT2_I_SIZE(&file->inode) + offset;
+ else
+ return EXT2_ET_INVALID_ARGUMENT;
+
+ if (ret_pos)
+ *ret_pos = file->pos;
+
+ return 0;
+}
+
+errcode_t ext2fs_file_lseek(ext2_file_t file, ext2_off_t offset,
+ int whence, ext2_off_t *ret_pos)
+{
+ __u64 loffset, ret_loffset = 0;
+ errcode_t retval;
+
+ loffset = offset;
+ retval = ext2fs_file_llseek(file, loffset, whence, &ret_loffset);
+ if (ret_pos)
+ *ret_pos = (ext2_off_t) ret_loffset;
+ return retval;
+}
+
+
+/*
+ * This function returns the size of the file, according to the inode
+ */
+errcode_t ext2fs_file_get_lsize(ext2_file_t file, __u64 *ret_size)
+{
+ if (file->magic != EXT2_ET_MAGIC_EXT2_FILE)
+ return EXT2_ET_MAGIC_EXT2_FILE;
+ *ret_size = EXT2_I_SIZE(&file->inode);
+ return 0;
+}
+
+/*
+ * This function returns the size of the file, according to the inode
+ */
+ext2_off_t ext2fs_file_get_size(ext2_file_t file)
+{
+ __u64 size;
+
+ if (ext2fs_file_get_lsize(file, &size))
+ return 0;
+ if ((size >> 32) != 0)
+ return 0;
+ return size;
+}
+
+/* Zero the parts of the last block that are past EOF. */
+static errcode_t ext2fs_file_zero_past_offset(ext2_file_t file,
+ ext2_off64_t offset)
+{
+ ext2_filsys fs = file->fs;
+ char *b = NULL;
+ ext2_off64_t off = offset % fs->blocksize;
+ blk64_t blk;
+ int ret_flags;
+ errcode_t retval;
+
+ if (off == 0)
+ return 0;
+
+ retval = sync_buffer_position(file);
+ if (retval)
+ return retval;
+
+ /* Is there an initialized block at the end? */
+ retval = ext2fs_bmap2(fs, file->ino, NULL, NULL, 0,
+ offset / fs->blocksize, &ret_flags, &blk);
+ if (retval)
+ return retval;
+ if ((blk == 0) || (ret_flags & BMAP_RET_UNINIT))
+ return 0;
+
+ /* Zero to the end of the block */
+ retval = ext2fs_get_mem(fs->blocksize, &b);
+ if (retval)
+ return retval;
+
+ /* Read/zero/write block */
+ retval = io_channel_read_blk64(fs->io, blk, 1, b);
+ if (retval)
+ goto out;
+
+ memset(b + off, 0, fs->blocksize - off);
+
+ retval = io_channel_write_blk64(fs->io, blk, 1, b);
+ if (retval)
+ goto out;
+
+out:
+ ext2fs_free_mem(&b);
+ return retval;
+}
+
+/*
+ * This function sets the size of the file, truncating it if necessary
+ *
+ */
+errcode_t ext2fs_file_set_size2(ext2_file_t file, ext2_off64_t size)
+{
+ ext2_off64_t old_size;
+ errcode_t retval;
+ blk64_t old_truncate, truncate_block;
+
+ EXT2_CHECK_MAGIC(file, EXT2_ET_MAGIC_EXT2_FILE);
+
+ if (size && ext2fs_file_block_offset_too_big(file->fs, &file->inode,
+ (size - 1) / file->fs->blocksize))
+ return EXT2_ET_FILE_TOO_BIG;
+ truncate_block = ((size + file->fs->blocksize - 1) >>
+ EXT2_BLOCK_SIZE_BITS(file->fs->super));
+ old_size = EXT2_I_SIZE(&file->inode);
+ old_truncate = ((old_size + file->fs->blocksize - 1) >>
+ EXT2_BLOCK_SIZE_BITS(file->fs->super));
+
+ retval = ext2fs_inode_size_set(file->fs, &file->inode, size);
+ if (retval)
+ return retval;
+
+ if (file->ino) {
+ retval = ext2fs_write_inode(file->fs, file->ino, &file->inode);
+ if (retval)
+ return retval;
+ }
+
+ retval = ext2fs_file_zero_past_offset(file, size);
+ if (retval)
+ return retval;
+
+ if (truncate_block >= old_truncate)
+ return 0;
+
+ return ext2fs_punch(file->fs, file->ino, &file->inode, 0,
+ truncate_block, ~0ULL);
+}
+
+errcode_t ext2fs_file_set_size(ext2_file_t file, ext2_off_t size)
+{
+ return ext2fs_file_set_size2(file, size);
+}
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-23 05:47:53 +0000