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/*
* Copyright (c) 2012 Dave Vasilevsky <dave@vasilevsky.ca>
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR(S) ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
* IN NO EVENT SHALL THE AUTHOR(S) BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include "dir.h"
#include "fs.h"
#include "swap.h"
#include <string.h>
#include <sys/stat.h>
/* Read some directory metadata, updating the dir structure as necessary */
static sqfs_err sqfs_dir_md_read(sqfs *fs, sqfs_dir *dir, void *buf,
size_t size);
/* Fast forwards to a directory header. */
typedef sqfs_err sqfs_dir_header_f(sqfs *fs, sqfs_md_cursor *cur,
struct squashfs_dir_index *index, bool *stop, void *arg);
static sqfs_err sqfs_dir_ff_header(sqfs *fs, sqfs_inode *inode, sqfs_dir *dir,
sqfs_dir_header_f func, void *arg);
/* Fast forward a directory to the given offset. Return error if it doesn't
exist. */
static sqfs_err sqfs_dir_ff_offset(sqfs *fs, sqfs_inode *inode, sqfs_dir *dir,
sqfs_off_t offset);
static sqfs_err sqfs_dir_md_read(sqfs *fs, sqfs_dir *dir, void *buf,
size_t size) {
dir->offset += size;
return sqfs_md_read(fs, &dir->cur, buf, size);
}
sqfs_err sqfs_dir_open(sqfs *fs, sqfs_inode *inode, sqfs_dir *dir,
off_t offset) {
if (!S_ISDIR(inode->base.mode))
return SQFS_ERR;
memset(dir, 0, sizeof(*dir));
dir->cur.block = inode->xtra.dir.start_block +
fs->sb.directory_table_start;
dir->cur.offset = inode->xtra.dir.offset;
dir->offset = 0;
dir->total = inode->xtra.dir.dir_size - 3;
if (offset) {
/* Fast forward to the given offset */
sqfs_err err = sqfs_dir_ff_offset(fs, inode, dir, offset);
if (err)
return err;
}
return SQFS_OK;
}
void sqfs_dentry_init(sqfs_dir_entry *entry, char *namebuf) {
entry->name = namebuf;
}
sqfs_off_t sqfs_dentry_offset(sqfs_dir_entry *entry) {
return entry->offset;
}
sqfs_off_t sqfs_dentry_next_offset(sqfs_dir_entry *entry) {
return entry->next_offset;
}
int sqfs_dentry_type(sqfs_dir_entry *entry) {
return entry->type;
}
sqfs_mode_t sqfs_dentry_mode(sqfs_dir_entry *entry) {
return sqfs_mode(sqfs_dentry_type(entry));
}
sqfs_inode_id sqfs_dentry_inode(sqfs_dir_entry *entry) {
return entry->inode;
}
sqfs_inode_num sqfs_dentry_inode_num(sqfs_dir_entry *entry) {
return entry->inode_number;
}
size_t sqfs_dentry_name_size(sqfs_dir_entry *entry) {
return entry->name_size;
}
const char *sqfs_dentry_name(sqfs_dir_entry *entry) {
if (!entry->name)
return NULL;
entry->name[sqfs_dentry_name_size(entry)] = '\0';
return entry->name;
}
bool sqfs_dentry_is_dir(sqfs_dir_entry *entry) {
return S_ISDIR(sqfs_dentry_mode(entry));
}
bool sqfs_dir_next(sqfs *fs, sqfs_dir *dir, sqfs_dir_entry *entry,
sqfs_err *err) {
struct squashfs_dir_entry e;
*err = SQFS_OK;
entry->offset = dir->offset;
while (dir->header.count == 0) {
if (dir->offset >= dir->total)
return false;
if ((*err = sqfs_dir_md_read(fs, dir, &dir->header, sizeof(dir->header))))
return false;
sqfs_swapin_dir_header(&dir->header);
++(dir->header.count); /* biased by one */
}
if ((*err = sqfs_dir_md_read(fs, dir, &e, sizeof(e))))
return false;
sqfs_swapin_dir_entry(&e);
--(dir->header.count);
entry->type = e.type;
entry->name_size = e.size + 1;
entry->inode = ((uint64_t)dir->header.start_block << 16) + e.offset;
/* e.inode_number is signed */
entry->inode_number = dir->header.inode_number + (int16_t)e.inode_number;
*err = sqfs_dir_md_read(fs, dir, entry->name, sqfs_dentry_name_size(entry));
if (*err)
return false;
entry->next_offset = dir->offset;
return true;
}
static sqfs_err sqfs_dir_ff_header(sqfs *fs, sqfs_inode *inode,
sqfs_dir *dir, sqfs_dir_header_f func, void *arg) {
struct squashfs_dir_index idx;
sqfs_md_cursor cur = inode->next;
size_t count = inode->xtra.dir.idx_count;
if (count == 0)
return SQFS_OK;
while (count--) {
sqfs_err err;
bool stop = 0;
if ((err = sqfs_md_read(fs, &cur, &idx, sizeof(idx))))
return err;
sqfs_swapin_dir_index(&idx);
if ((err = func(fs, &cur, &idx, &stop, arg)))
return err;
if (stop)
break;
dir->cur.block = idx.start_block + fs->sb.directory_table_start;
dir->offset = idx.index;
}
dir->cur.offset = (dir->cur.offset + dir->offset) % SQUASHFS_METADATA_SIZE;
return SQFS_OK;
}
/* Helper for sqfs_dir_ff_offset */
static sqfs_err sqfs_dir_ff_offset_f(sqfs *fs, sqfs_md_cursor *cur,
struct squashfs_dir_index *index, bool *stop, void *arg) {
sqfs_off_t offset = *(sqfs_off_t*)arg;
if (index->index >= offset) {
*stop = true;
return SQFS_OK;
}
return sqfs_md_read(fs, cur, NULL, index->size + 1); /* skip name */
}
static sqfs_err sqfs_dir_ff_offset(sqfs *fs, sqfs_inode *inode, sqfs_dir *dir,
sqfs_off_t offset) {
sqfs_err err;
sqfs_dir_entry entry;
err = sqfs_dir_ff_header(fs, inode, dir, sqfs_dir_ff_offset_f, &offset);
if (err)
return err;
sqfs_dentry_init(&entry, NULL);
while (dir->offset < offset && sqfs_dir_next(fs, dir, &entry, &err))
; /* pass */
if (err)
return err;
return dir->offset == offset ? SQFS_OK : SQFS_ERR;
}
/* Helper for sqfs_dir_lookup */
typedef struct {
const char *cmp;
size_t cmplen;
char *name;
} sqfs_dir_ff_name_t;
static sqfs_err sqfs_dir_ff_name_f(sqfs *fs, sqfs_md_cursor *cur,
struct squashfs_dir_index *index, bool *stop, void *arg) {
sqfs_err err;
sqfs_dir_ff_name_t *args = (sqfs_dir_ff_name_t*)arg;
size_t name_size = index->size + 1;
if ((err = sqfs_md_read(fs, cur, args->name, name_size)))
return err;
args->name[name_size] = '\0';
int order = strncmp(args->name, args->cmp, args->cmplen);
if (order > 0 || (order == 0 && name_size > args->cmplen))
*stop = true;
return SQFS_OK;
}
sqfs_err sqfs_dir_lookup(sqfs *fs, sqfs_inode *inode,
const char *name, size_t namelen, sqfs_dir_entry *entry, bool *found) {
sqfs_err err;
sqfs_dir dir;
sqfs_dir_ff_name_t arg;
*found = false;
if ((err = sqfs_dir_open(fs, inode, &dir, 0)))
return err;
/* Fast forward to header */
arg.cmp = name;
arg.cmplen = namelen;
arg.name = entry->name;
if ((err = sqfs_dir_ff_header(fs, inode, &dir, sqfs_dir_ff_name_f, &arg)))
return err;
/* Iterate to find the right entry */
while (sqfs_dir_next(fs, &dir, entry, &err)) {
int order = strncmp(sqfs_dentry_name(entry), name, namelen);
if (order == 0 && sqfs_dentry_name_size(entry) == namelen)
*found = true;
if (order >= 0)
break;
}
return err;
}
sqfs_err sqfs_lookup_path(sqfs *fs, sqfs_inode *inode, const char *path,
bool *found) {
sqfs_err err;
sqfs_name buf;
sqfs_dir_entry entry;
*found = false;
sqfs_dentry_init(&entry, buf);
while (*path) {
const char *name;
size_t size;
bool dfound;
/* Find next path component */
while (*path == '/') /* skip leading slashes */
++path;
name = path;
while (*path && *path != '/')
++path;
size = path - name;
if (size == 0) /* we're done */
break;
if ((err = sqfs_dir_lookup(fs, inode, name, size, &entry, &dfound)))
return err;
if (!dfound)
return SQFS_OK; /* not found */
if ((err = sqfs_inode_get(fs, inode, sqfs_dentry_inode(&entry))))
return err;
}
*found = true;
return SQFS_OK;
}
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