import ext2fs lib to prep for new e2fsprogs

1 files changed, 378 insertions, 0 deletions

diff --git a/e2fsprogs/ext2fs/fileio.c b/e2fsprogs/ext2fs/fileio.c
new file mode 100644
index 0000000..3e42cbc
--- /dev/null
+++ b/e2fsprogs/ext2fs/fileio.c
@@ -0,0 +1,378 @@
+/*
+ * 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 Public
+ * License.
+ * %End-Header%
+ */
+
+#include <stdio.h>
+#include <string.h>
+#if HAVE_UNISTD_H
+#include <unistd.h>
+#endif
+
+#include "ext2_fs.h"
+#include "ext2fs.h"
+
+struct ext2_file {
+	errcode_t		magic;
+	ext2_filsys 		fs;
+	ext2_ino_t		ino;
+	struct ext2_inode	inode;
+	int 			flags;
+	__u64			pos;
+	blk_t			blockno;
+	blk_t			physblock;
+	char 			*buf;
+};
+
+#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_mem(fs->blocksize * 3, &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 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;
+	
+	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;
+
+	/*
+	 * OK, the physical block hasn't been allocated yet.
+	 * Allocate it.
+	 */
+	if (!file->physblock) {
+		retval = ext2fs_bmap(fs, file->ino, &file->inode,
+				     BMAP_BUFFER, file->ino ? BMAP_ALLOC : 0,
+				     file->blockno, &file->physblock);
+		if (retval)
+			return retval;
+	}
+
+	retval = io_channel_write_blk(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)
+{
+	blk_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;
+
+	if (!(file->flags & EXT2_FILE_BUF_VALID)) {
+		retval = ext2fs_bmap(fs, file->ino, &file->inode,
+				     BMAP_BUFFER, 0, file->blockno,
+				     &file->physblock);
+		if (retval)
+			return retval;
+		if (!dontfill) {
+			if (file->physblock) {
+				retval = io_channel_read_blk(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;
+}
+
+
+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;
+
+	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;
+}
+
+
+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;
+
+	EXT2_CHECK_MAGIC(file, EXT2_ET_MAGIC_EXT2_FILE);
+	fs = file->fs;
+
+	if (!(file->flags & EXT2_FILE_WRITE))
+		return EXT2_ET_FILE_RO;
+
+	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);
+		file->pos += c;
+		ptr += c;
+		count += c;
+		nbytes -= c;
+	}
+	
+fail:
+	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;
+	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;
+}
+
+/*
+ * This function sets the size of the file, truncating it if necessary
+ * 
+ * XXX still need to call truncate
+ */
+errcode_t ext2fs_file_set_size(ext2_file_t file, ext2_off_t size)
+{
+	errcode_t	retval;
+	EXT2_CHECK_MAGIC(file, EXT2_ET_MAGIC_EXT2_FILE);
+	
+	file->inode.i_size = size;
+	file->inode.i_size_high = 0;
+	if (file->ino) {
+		retval = ext2fs_write_inode(file->fs, file->ino, &file->inode);
+		if (retval)
+			return retval;
+	}
+
+	/* 
+	 * XXX truncate inode if necessary
+	 */
+
+	return 0;
+}