diff options
Diffstat (limited to 'lib/dir.c')
| -rw-r--r-- | lib/dir.c | 169 |
1 files changed, 169 insertions, 0 deletions
diff --git a/lib/dir.c b/lib/dir.c new file mode 100644 index 0000000..46805b4 --- /dev/null +++ b/lib/dir.c @@ -0,0 +1,169 @@ +// SPDX-License-Identifier: GPL-2.0+ OR Apache-2.0 +#include "erofs/print.h" +#include "erofs/dir.h" +#include <stdlib.h> +#include <sys/stat.h> + +static int traverse_dirents(struct erofs_dir_context *ctx, + void *dentry_blk, unsigned int lblk, + unsigned int next_nameoff, unsigned int maxsize, + bool fsck) +{ + struct erofs_dirent *de = dentry_blk; + const struct erofs_dirent *end = dentry_blk + next_nameoff; + const char *prev_name = NULL; + const char *errmsg; + unsigned int prev_namelen = 0; + int ret = 0; + bool silent = false; + + while (de < end) { + const char *de_name; + unsigned int de_namelen; + unsigned int nameoff; + + nameoff = le16_to_cpu(de->nameoff); + de_name = (char *)dentry_blk + nameoff; + + /* the last dirent check */ + if (de + 1 >= end) + de_namelen = strnlen(de_name, maxsize - nameoff); + else + de_namelen = le16_to_cpu(de[1].nameoff) - nameoff; + + ctx->de_nid = le64_to_cpu(de->nid); + erofs_dbg("traversed nid (%llu)", ctx->de_nid | 0ULL); + + ret = -EFSCORRUPTED; + /* corrupted entry check */ + if (nameoff != next_nameoff) { + errmsg = "bogus dirent nameoff"; + break; + } + + if (nameoff + de_namelen > maxsize || + de_namelen > EROFS_NAME_LEN) { + errmsg = "bogus dirent namelen"; + break; + } + + if (fsck && prev_name) { + int cmp = strncmp(prev_name, de_name, + min(prev_namelen, de_namelen)); + + if (cmp > 0 || (cmp == 0 && + prev_namelen >= de_namelen)) { + errmsg = "wrong dirent name order"; + break; + } + } + + if (fsck && de->file_type >= EROFS_FT_MAX) { + errmsg = "invalid file type %u"; + break; + } + + ctx->dname = de_name; + ctx->de_namelen = de_namelen; + ctx->de_ftype = de->file_type; + ctx->dot_dotdot = is_dot_dotdot_len(de_name, de_namelen); + if (ctx->dot_dotdot) { + switch (de_namelen) { + case 2: + if (fsck && + (ctx->flags & EROFS_READDIR_DOTDOT_FOUND)) { + errmsg = "duplicated `..' dirent"; + goto out; + } + ctx->flags |= EROFS_READDIR_DOTDOT_FOUND; + if (sbi.root_nid == ctx->dir->nid) { + ctx->pnid = sbi.root_nid; + ctx->flags |= EROFS_READDIR_VALID_PNID; + } + if (fsck && + (ctx->flags & EROFS_READDIR_VALID_PNID) && + ctx->de_nid != ctx->pnid) { + errmsg = "corrupted `..' dirent"; + goto out; + } + break; + case 1: + if (fsck && + (ctx->flags & EROFS_READDIR_DOT_FOUND)) { + errmsg = "duplicated `.' dirent"; + goto out; + } + + ctx->flags |= EROFS_READDIR_DOT_FOUND; + if (fsck && ctx->de_nid != ctx->dir->nid) { + errmsg = "corrupted `.' dirent"; + goto out; + } + break; + } + } + ret = ctx->cb(ctx); + if (ret) { + silent = true; + break; + } + prev_name = de_name; + prev_namelen = de_namelen; + next_nameoff += de_namelen; + ++de; + } +out: + if (ret && !silent) + erofs_err("%s @ nid %llu, lblk %u, index %lu", + errmsg, ctx->dir->nid | 0ULL, lblk, + (de - (struct erofs_dirent *)dentry_blk) | 0UL); + return ret; +} + +int erofs_iterate_dir(struct erofs_dir_context *ctx, bool fsck) +{ + struct erofs_inode *dir = ctx->dir; + int err = 0; + erofs_off_t pos; + char buf[EROFS_BLKSIZ]; + + if ((dir->i_mode & S_IFMT) != S_IFDIR) + return -ENOTDIR; + + ctx->flags &= ~EROFS_READDIR_ALL_SPECIAL_FOUND; + pos = 0; + while (pos < dir->i_size) { + erofs_blk_t lblk = erofs_blknr(pos); + erofs_off_t maxsize = min_t(erofs_off_t, + dir->i_size - pos, EROFS_BLKSIZ); + const struct erofs_dirent *de = (const void *)buf; + unsigned int nameoff; + + err = erofs_pread(dir, buf, maxsize, pos); + if (err) { + erofs_err("I/O error occurred when reading dirents @ nid %llu, lblk %u: %d", + dir->nid | 0ULL, lblk, err); + return err; + } + + nameoff = le16_to_cpu(de->nameoff); + if (nameoff < sizeof(struct erofs_dirent) || + nameoff >= PAGE_SIZE) { + erofs_err("invalid de[0].nameoff %u @ nid %llu, lblk %u", + nameoff, dir->nid | 0ULL, lblk); + return -EFSCORRUPTED; + } + err = traverse_dirents(ctx, buf, lblk, nameoff, maxsize, fsck); + if (err) + break; + pos += maxsize; + } + + if (fsck && (ctx->flags & EROFS_READDIR_ALL_SPECIAL_FOUND) != + EROFS_READDIR_ALL_SPECIAL_FOUND) { + erofs_err("`.' or `..' dirent is missing @ nid %llu", + dir->nid | 0ULL); + return -EFSCORRUPTED; + } + return err; +} |