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// SPDX-License-Identifier: GPL-2.0-only
/*
* Copyright (C) 2017-2018 HUAWEI, Inc.
* https://www.huawei.com/
* Copyright (C) 2022, Alibaba Cloud
*/
#include "internal.h"
static int erofs_fill_dentries(struct inode *dir, struct dir_context *ctx,
void *dentry_blk, struct erofs_dirent *de,
unsigned int nameoff, unsigned int maxsize)
{
const struct erofs_dirent *end = dentry_blk + nameoff;
while (de < end) {
const char *de_name;
unsigned int de_namelen;
unsigned char d_type;
d_type = fs_ftype_to_dtype(de->file_type);
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(dir->i_sb, "bogus dirent @ nid %llu",
EROFS_I(dir)->nid);
DBG_BUGON(1);
return -EFSCORRUPTED;
}
if (!dir_emit(ctx, de_name, de_namelen,
le64_to_cpu(de->nid), d_type))
return 1;
++de;
ctx->pos += sizeof(struct erofs_dirent);
}
return 0;
}
static int erofs_readdir(struct file *f, struct dir_context *ctx)
{
struct inode *dir = file_inode(f);
struct erofs_buf buf = __EROFS_BUF_INITIALIZER;
struct super_block *sb = dir->i_sb;
unsigned long bsz = sb->s_blocksize;
const size_t dirsize = i_size_read(dir);
unsigned int i = erofs_blknr(sb, ctx->pos);
unsigned int ofs = erofs_blkoff(sb, ctx->pos);
int err = 0;
bool initial = true;
buf.inode = dir;
while (ctx->pos < dirsize) {
struct erofs_dirent *de;
unsigned int nameoff, maxsize;
de = erofs_bread(&buf, i, EROFS_KMAP);
if (IS_ERR(de)) {
erofs_err(sb, "fail to readdir of logical block %u of nid %llu",
i, EROFS_I(dir)->nid);
err = PTR_ERR(de);
break;
}
nameoff = le16_to_cpu(de->nameoff);
if (nameoff < sizeof(struct erofs_dirent) || nameoff >= bsz) {
erofs_err(sb, "invalid de[0].nameoff %u @ nid %llu",
nameoff, EROFS_I(dir)->nid);
err = -EFSCORRUPTED;
break;
}
maxsize = min_t(unsigned int, dirsize - ctx->pos + ofs, bsz);
/* search dirents at the arbitrary position */
if (initial) {
initial = false;
ofs = roundup(ofs, sizeof(struct erofs_dirent));
ctx->pos = erofs_pos(sb, i) + ofs;
if (ofs >= nameoff)
goto skip_this;
}
err = erofs_fill_dentries(dir, ctx, de, (void *)de + ofs,
nameoff, maxsize);
if (err)
break;
skip_this:
ctx->pos = erofs_pos(sb, i) + maxsize;
++i;
ofs = 0;
}
erofs_put_metabuf(&buf);
return err < 0 ? err : 0;
}
const struct file_operations erofs_dir_fops = {
.llseek = generic_file_llseek,
.read = generic_read_dir,
.iterate_shared = erofs_readdir,
};
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