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/*
* namei.c --- ext2fs directory lookup operations
*
* Copyright (C) 1993, 1994 Theodore Ts'o. This file may be
* redistributed under the terms of the GNU Public License.
*/
#include <stdio.h>
#include <string.h>
#include <unistd.h>
#include <stdlib.h>
#if HAVE_ERRNO_H
#include <errno.h>
#endif
#include <linux/ext2_fs.h>
#include "ext2fs.h"
struct dir_context {
ino_t dir;
int flags;
char *buf;
int (*func)(struct ext2_dir_entry *dirent,
int offset,
int blocksize,
char *buf,
void *private);
void *private;
errcode_t errcode;
};
static int process_dir_block(ext2_filsys fs,
blk_t *blocknr,
int blockcnt,
void *private);
errcode_t ext2fs_dir_iterate(ext2_filsys fs,
ino_t dir,
int flags,
char *block_buf,
int (*func)(struct ext2_dir_entry *dirent,
int offset,
int blocksize,
char *buf,
void *private),
void *private)
{
struct dir_context ctx;
errcode_t retval;
EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);
retval = ext2fs_check_directory(fs, dir);
if (retval)
return retval;
ctx.dir = dir;
ctx.flags = flags;
if (block_buf)
ctx.buf = block_buf;
else {
ctx.buf = malloc(fs->blocksize);
if (!ctx.buf)
return ENOMEM;
}
ctx.func = func;
ctx.private = private;
ctx.errcode = 0;
retval = ext2fs_block_iterate(fs, dir, 0, 0, process_dir_block, &ctx);
if (!block_buf)
free(ctx.buf);
if (retval)
return retval;
return ctx.errcode;
}
static int process_dir_block(ext2_filsys fs,
blk_t *blocknr,
int blockcnt,
void *private)
{
struct dir_context *ctx = (struct dir_context *) private;
int offset = 0;
int ret;
int changed = 0;
int do_abort = 0;
struct ext2_dir_entry *dirent;
if (blockcnt < 0)
return 0;
ctx->errcode = ext2fs_read_dir_block(fs, *blocknr, ctx->buf);
if (ctx->errcode)
return BLOCK_ABORT;
while (offset < fs->blocksize) {
dirent = (struct ext2_dir_entry *) (ctx->buf + offset);
if (!dirent->inode &&
!(ctx->flags & DIRENT_FLAG_INCLUDE_EMPTY))
goto next;
ret = (ctx->func)(dirent, offset, fs->blocksize,
ctx->buf, ctx->private);
if (ret & DIRENT_CHANGED)
changed++;
if (ret & DIRENT_ABORT) {
do_abort++;
break;
}
next:
if (((offset + dirent->rec_len) > fs->blocksize) ||
(dirent->rec_len < 8) ||
((dirent->name_len+8) > dirent->rec_len)) {
ctx->errcode = EXT2_ET_DIR_CORRUPTED;
return BLOCK_ABORT;
}
offset += dirent->rec_len;
}
if (changed) {
ctx->errcode = ext2fs_write_dir_block(fs, *blocknr, ctx->buf);
if (ctx->errcode)
return BLOCK_ABORT;
}
if (do_abort)
return BLOCK_ABORT;
return 0;
}
struct lookup_struct {
const char *name;
int len;
ino_t *inode;
int found;
};
static int lookup_proc(struct ext2_dir_entry *dirent,
int offset,
int blocksize,
char *buf,
void *private)
{
struct lookup_struct *ls = (struct lookup_struct *) private;
if (ls->len != dirent->name_len)
return 0;
if (strncmp(ls->name, dirent->name, dirent->name_len))
return 0;
*ls->inode = dirent->inode;
ls->found++;
return DIRENT_ABORT;
}
errcode_t ext2fs_lookup(ext2_filsys fs, ino_t dir, const char *name,
int namelen, char *buf, ino_t *inode)
{
errcode_t retval;
struct lookup_struct ls;
EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);
ls.name = name;
ls.len = namelen;
ls.inode = inode;
ls.found = 0;
retval = ext2fs_dir_iterate(fs, dir, 0, buf, lookup_proc, &ls);
if (retval)
return retval;
return (ls.found) ? 0 : ENOENT;
}
errcode_t ext2fs_namei(ext2_filsys fs, ino_t root, ino_t cwd, const char *name,
ino_t *inode)
{
ino_t dir = cwd;
char *buf;
const char *p = name, *q;
int len;
errcode_t retval;
EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);
buf = malloc(fs->blocksize);
if (!buf)
return ENOMEM;
if (*p == '/') {
p++;
dir = root;
}
while (*p) {
q = strchr(p, '/');
if (q)
len = q - p;
else
len = strlen(p);
if (len) {
retval = ext2fs_lookup(fs, dir, p, len, buf, &dir);
if (retval) {
free(buf);
return retval;
}
}
if (q)
p = q+1;
else
break;
}
*inode = dir;
free(buf);
return 0;
}
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