diff options
Diffstat (limited to 'fs/erofs/fs.c')
| -rw-r--r-- | fs/erofs/fs.c | 267 |
1 files changed, 267 insertions, 0 deletions
diff --git a/fs/erofs/fs.c b/fs/erofs/fs.c new file mode 100644 index 0000000000..89269750f8 --- /dev/null +++ b/fs/erofs/fs.c @@ -0,0 +1,267 @@ +// 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; +} |