blob: b572d17daeab1dde95235e97c6fa3c4d10bb5579 [file] [log] [blame]
// SPDX-License-Identifier: GPL-2.0+
/*
* erofs-utils/lib/namei.c
*
* Created by Li Guifu <blucerlee@gmail.com>
*/
#include <sys/types.h>
#include <unistd.h>
#include <stdio.h>
#include <errno.h>
#include <sys/stat.h>
#include <config.h>
#if defined(HAVE_SYS_SYSMACROS_H)
#include <sys/sysmacros.h>
#endif
#include "erofs/print.h"
#include "erofs/io.h"
static dev_t erofs_new_decode_dev(u32 dev)
{
const unsigned int major = (dev & 0xfff00) >> 8;
const unsigned int minor = (dev & 0xff) | ((dev >> 12) & 0xfff00);
return makedev(major, minor);
}
static int erofs_read_inode_from_disk(struct erofs_inode *vi)
{
int ret, ifmt;
char buf[sizeof(struct erofs_inode_extended)];
struct erofs_inode_compact *dic;
struct erofs_inode_extended *die;
const erofs_off_t inode_loc = iloc(vi->nid);
ret = dev_read(buf, inode_loc, sizeof(*dic));
if (ret < 0)
return -EIO;
dic = (struct erofs_inode_compact *)buf;
ifmt = le16_to_cpu(dic->i_format);
vi->datalayout = erofs_inode_datalayout(ifmt);
if (vi->datalayout >= EROFS_INODE_DATALAYOUT_MAX) {
erofs_err("unsupported datalayout %u of nid %llu",
vi->datalayout, vi->nid | 0ULL);
return -EOPNOTSUPP;
}
switch (erofs_inode_version(ifmt)) {
case EROFS_INODE_LAYOUT_EXTENDED:
vi->inode_isize = sizeof(struct erofs_inode_extended);
ret = dev_read(buf + sizeof(*dic), inode_loc + sizeof(*dic),
sizeof(*die) - sizeof(*dic));
if (ret < 0)
return -EIO;
die = (struct erofs_inode_extended *)buf;
vi->xattr_isize = erofs_xattr_ibody_size(die->i_xattr_icount);
vi->i_mode = le16_to_cpu(die->i_mode);
switch (vi->i_mode & S_IFMT) {
case S_IFREG:
case S_IFDIR:
case S_IFLNK:
vi->u.i_blkaddr = le32_to_cpu(die->i_u.raw_blkaddr);
break;
case S_IFCHR:
case S_IFBLK:
vi->u.i_rdev =
erofs_new_decode_dev(le32_to_cpu(die->i_u.rdev));
break;
case S_IFIFO:
case S_IFSOCK:
vi->u.i_rdev = 0;
break;
default:
goto bogusimode;
}
vi->i_uid = le32_to_cpu(die->i_uid);
vi->i_gid = le32_to_cpu(die->i_gid);
vi->i_nlink = le32_to_cpu(die->i_nlink);
vi->i_ctime = le64_to_cpu(die->i_ctime);
vi->i_ctime_nsec = le64_to_cpu(die->i_ctime_nsec);
vi->i_size = le64_to_cpu(die->i_size);
break;
case EROFS_INODE_LAYOUT_COMPACT:
vi->inode_isize = sizeof(struct erofs_inode_compact);
vi->xattr_isize = erofs_xattr_ibody_size(dic->i_xattr_icount);
vi->i_mode = le16_to_cpu(dic->i_mode);
switch (vi->i_mode & S_IFMT) {
case S_IFREG:
case S_IFDIR:
case S_IFLNK:
vi->u.i_blkaddr = le32_to_cpu(dic->i_u.raw_blkaddr);
break;
case S_IFCHR:
case S_IFBLK:
vi->u.i_rdev =
erofs_new_decode_dev(le32_to_cpu(dic->i_u.rdev));
break;
case S_IFIFO:
case S_IFSOCK:
vi->u.i_rdev = 0;
break;
default:
goto bogusimode;
}
vi->i_uid = le16_to_cpu(dic->i_uid);
vi->i_gid = le16_to_cpu(dic->i_gid);
vi->i_nlink = le16_to_cpu(dic->i_nlink);
vi->i_ctime = sbi.build_time;
vi->i_ctime_nsec = sbi.build_time_nsec;
vi->i_size = le32_to_cpu(dic->i_size);
break;
default:
erofs_err("unsupported on-disk inode version %u of nid %llu",
erofs_inode_version(ifmt), vi->nid | 0ULL);
return -EOPNOTSUPP;
}
vi->flags = 0;
if (erofs_inode_is_data_compressed(vi->datalayout))
z_erofs_fill_inode(vi);
return 0;
bogusimode:
erofs_err("bogus i_mode (%o) @ nid %llu", vi->i_mode, vi->nid | 0ULL);
return -EFSCORRUPTED;
}
struct erofs_dirent *find_target_dirent(erofs_nid_t pnid,
void *dentry_blk,
const char *name, unsigned int len,
unsigned int nameoff,
unsigned int maxsize)
{
struct erofs_dirent *de = dentry_blk;
const struct erofs_dirent *end = dentry_blk + nameoff;
while (de < end) {
const char *de_name;
unsigned int de_namelen;
nameoff = le16_to_cpu(de->nameoff);
de_name = (char *)dentry_blk + nameoff;
/* the last dirent in the block? */
if (de + 1 >= end)
de_namelen = strnlen(de_name, maxsize - nameoff);
else
de_namelen = le16_to_cpu(de[1].nameoff) - nameoff;
/* a corrupted entry is found */
if (nameoff + de_namelen > maxsize ||
de_namelen > EROFS_NAME_LEN) {
erofs_err("bogus dirent @ nid %llu", pnid | 0ULL);
DBG_BUGON(1);
return ERR_PTR(-EFSCORRUPTED);
}
if (len == de_namelen && !memcmp(de_name, name, de_namelen))
return de;
++de;
}
return NULL;
}
struct nameidata {
erofs_nid_t nid;
unsigned int ftype;
};
int erofs_namei(struct nameidata *nd,
const char *name, unsigned int len)
{
erofs_nid_t nid = nd->nid;
int ret;
char buf[EROFS_BLKSIZ];
struct erofs_inode vi = { .nid = nid };
erofs_off_t offset;
ret = erofs_read_inode_from_disk(&vi);
if (ret)
return ret;
offset = 0;
while (offset < vi.i_size) {
erofs_off_t maxsize = min_t(erofs_off_t,
vi.i_size - offset, EROFS_BLKSIZ);
struct erofs_dirent *de = (void *)buf;
unsigned int nameoff;
ret = erofs_pread(&vi, buf, maxsize, offset);
if (ret)
return ret;
nameoff = le16_to_cpu(de->nameoff);
if (nameoff < sizeof(struct erofs_dirent) ||
nameoff >= PAGE_SIZE) {
erofs_err("invalid de[0].nameoff %u @ nid %llu",
nameoff, nid | 0ULL);
return -EFSCORRUPTED;
}
de = find_target_dirent(nid, buf, name, len,
nameoff, maxsize);
if (IS_ERR(de))
return PTR_ERR(de);
if (de) {
nd->nid = le64_to_cpu(de->nid);
return 0;
}
offset += maxsize;
}
return -ENOENT;
}
static int link_path_walk(const char *name, struct nameidata *nd)
{
nd->nid = sbi.root_nid;
while (*name == '/')
name++;
/* At this point we know we have a real path component. */
while (*name != '\0') {
const char *p = name;
int ret;
do {
++p;
} while (*p != '\0' && *p != '/');
DBG_BUGON(p <= name);
ret = erofs_namei(nd, name, p - name);
if (ret)
return ret;
name = p;
/* Skip until no more slashes. */
for (name = p; *name == '/'; ++name);
}
return 0;
}
int erofs_ilookup(const char *path, struct erofs_inode *vi)
{
int ret;
struct nameidata nd;
ret = link_path_walk(path, &nd);
if (ret)
return ret;
vi->nid = nd.nid;
return erofs_read_inode_from_disk(vi);
}