blob: 89269750f8ba35062fb0d370df86a14c97616fee [file] [log] [blame]
// SPDX-License-Identifier: GPL-2.0+
#include "internal.h"
#include <fs_internal.h>
struct erofs_sb_info sbi;
static struct erofs_ctxt {
struct disk_partition cur_part_info;
struct blk_desc *cur_dev;
} ctxt;
int erofs_dev_read(int device_id, void *buf, u64 offset, size_t len)
{
lbaint_t sect = offset >> ctxt.cur_dev->log2blksz;
int off = offset & (ctxt.cur_dev->blksz - 1);
if (!ctxt.cur_dev)
return -EIO;
if (fs_devread(ctxt.cur_dev, &ctxt.cur_part_info, sect,
off, len, buf))
return 0;
return -EIO;
}
int erofs_blk_read(void *buf, erofs_blk_t start, u32 nblocks)
{
return erofs_dev_read(0, buf, blknr_to_addr(start),
blknr_to_addr(nblocks));
}
int erofs_probe(struct blk_desc *fs_dev_desc,
struct disk_partition *fs_partition)
{
int ret;
ctxt.cur_dev = fs_dev_desc;
ctxt.cur_part_info = *fs_partition;
ret = erofs_read_superblock();
if (ret)
goto error;
return 0;
error:
ctxt.cur_dev = NULL;
return ret;
}
struct erofs_dir_stream {
struct fs_dir_stream fs_dirs;
struct fs_dirent dirent;
struct erofs_inode inode;
char dblk[EROFS_BLKSIZ];
unsigned int maxsize, de_end;
erofs_off_t pos;
};
static int erofs_readlink(struct erofs_inode *vi)
{
size_t len = vi->i_size;
char *target;
int err;
target = malloc(len + 1);
if (!target)
return -ENOMEM;
target[len] = '\0';
err = erofs_pread(vi, target, len, 0);
if (err)
goto err_out;
err = erofs_ilookup(target, vi);
if (err)
goto err_out;
err_out:
free(target);
return err;
}
int erofs_opendir(const char *filename, struct fs_dir_stream **dirsp)
{
struct erofs_dir_stream *dirs;
int err;
dirs = calloc(1, sizeof(*dirs));
if (!dirs)
return -ENOMEM;
err = erofs_ilookup(filename, &dirs->inode);
if (err)
goto err_out;
if (S_ISLNK(dirs->inode.i_mode)) {
err = erofs_readlink(&dirs->inode);
if (err)
goto err_out;
}
if (!S_ISDIR(dirs->inode.i_mode)) {
err = -ENOTDIR;
goto err_out;
}
*dirsp = (struct fs_dir_stream *)dirs;
return 0;
err_out:
free(dirs);
return err;
}
int erofs_readdir(struct fs_dir_stream *fs_dirs, struct fs_dirent **dentp)
{
struct erofs_dir_stream *dirs = (struct erofs_dir_stream *)fs_dirs;
struct fs_dirent *dent = &dirs->dirent;
erofs_off_t pos = dirs->pos;
unsigned int nameoff, de_namelen;
struct erofs_dirent *de;
char *de_name;
int err;
if (pos >= dirs->inode.i_size)
return 1;
if (!dirs->maxsize) {
dirs->maxsize = min_t(unsigned int, EROFS_BLKSIZ,
dirs->inode.i_size - pos);
err = erofs_pread(&dirs->inode, dirs->dblk,
dirs->maxsize, pos);
if (err)
return err;
de = (struct erofs_dirent *)dirs->dblk;
dirs->de_end = le16_to_cpu(de->nameoff);
if (dirs->de_end < sizeof(struct erofs_dirent) ||
dirs->de_end >= EROFS_BLKSIZ) {
erofs_err("invalid de[0].nameoff %u @ nid %llu",
dirs->de_end, de->nid | 0ULL);
return -EFSCORRUPTED;
}
}
de = (struct erofs_dirent *)(dirs->dblk + erofs_blkoff(pos));
nameoff = le16_to_cpu(de->nameoff);
de_name = (char *)dirs->dblk + nameoff;
/* the last dirent in the block? */
if (de + 1 >= (struct erofs_dirent *)(dirs->dblk + dirs->de_end))
de_namelen = strnlen(de_name, dirs->maxsize - nameoff);
else
de_namelen = le16_to_cpu(de[1].nameoff) - nameoff;
/* a corrupted entry is found */
if (nameoff + de_namelen > dirs->maxsize ||
de_namelen > EROFS_NAME_LEN) {
erofs_err("bogus dirent @ nid %llu", de->nid | 0ULL);
DBG_BUGON(1);
return -EFSCORRUPTED;
}
memcpy(dent->name, de_name, de_namelen);
dent->name[de_namelen] = '\0';
if (de->file_type == EROFS_FT_DIR) {
dent->type = FS_DT_DIR;
} else if (de->file_type == EROFS_FT_SYMLINK) {
dent->type = FS_DT_LNK;
} else {
struct erofs_inode vi;
dent->type = FS_DT_REG;
vi.nid = de->nid;
err = erofs_read_inode_from_disk(&vi);
if (err)
return err;
dent->size = vi.i_size;
}
*dentp = dent;
pos += sizeof(*de);
if (erofs_blkoff(pos) >= dirs->de_end) {
pos = blknr_to_addr(erofs_blknr(pos) + 1);
dirs->maxsize = 0;
}
dirs->pos = pos;
return 0;
}
void erofs_closedir(struct fs_dir_stream *fs_dirs)
{
free(fs_dirs);
}
int erofs_exists(const char *filename)
{
struct erofs_inode vi;
int err;
err = erofs_ilookup(filename, &vi);
return err == 0;
}
int erofs_size(const char *filename, loff_t *size)
{
struct erofs_inode vi;
int err;
err = erofs_ilookup(filename, &vi);
if (err)
return err;
*size = vi.i_size;
return 0;
}
int erofs_read(const char *filename, void *buf, loff_t offset, loff_t len,
loff_t *actread)
{
struct erofs_inode vi;
int err;
err = erofs_ilookup(filename, &vi);
if (err)
return err;
if (S_ISLNK(vi.i_mode)) {
err = erofs_readlink(&vi);
if (err)
return err;
}
if (!len)
len = vi.i_size;
err = erofs_pread(&vi, buf, len, offset);
if (err) {
*actread = 0;
return err;
}
if (offset >= vi.i_size)
*actread = 0;
else if (offset + len > vi.i_size)
*actread = vi.i_size - offset;
else
*actread = len;
return 0;
}
void erofs_close(void)
{
ctxt.cur_dev = NULL;
}
int erofs_uuid(char *uuid_str)
{
if (IS_ENABLED(CONFIG_LIB_UUID)) {
if (ctxt.cur_dev)
uuid_bin_to_str(sbi.uuid, uuid_str,
UUID_STR_FORMAT_STD);
return 0;
}
return -ENOSYS;
}