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/* SPDX-License-Identifier: LGPL-3.0-or-later */
/*
* unix_dir_iterator.c
*
* Copyright (C) 2023 David Oberhollenzer <goliath@infraroot.at>
*/
#include "config.h"
#include "util/dir_iterator.h"
#include "util/util.h"
#include "sqfs/error.h"
#include <sys/stat.h>
#include <stdlib.h>
#include <dirent.h>
#include <string.h>
#include <errno.h>
typedef struct {
dir_iterator_t base;
struct dirent *ent;
struct stat sb;
int state;
DIR *dir;
} unix_dir_iterator_t;
static void dir_destroy(sqfs_object_t *obj)
{
unix_dir_iterator_t *it = (unix_dir_iterator_t *)obj;
closedir(it->dir);
free(it);
}
static int dir_read_link(dir_iterator_t *base, char **out)
{
unix_dir_iterator_t *it = (unix_dir_iterator_t *)base;
size_t size;
char *str;
*out = NULL;
if (it->state != 0 || it->ent == NULL) {
fputs("[BUG] no entry loaded, cannot readlink\n", stderr);
return SQFS_ERROR_INTERNAL;
}
if (!S_ISLNK(it->sb.st_mode)) {
fprintf(stderr, "[BUG] %s is not a symlink, cannot readlink\n",
it->ent->d_name);
it->state = SQFS_ERROR_INTERNAL;
return SQFS_ERROR_INTERNAL;
}
if ((sizeof(it->sb.st_size) > sizeof(size_t)) &&
it->sb.st_size > SIZE_MAX) {
goto fail_ov;
}
if (SZ_ADD_OV((size_t)it->sb.st_size, 1, &size))
goto fail_ov;
str = calloc(1, size);
if (str == NULL) {
perror(it->ent->d_name);
it->state = SQFS_ERROR_ALLOC;
return it->state;
}
if (readlinkat(dirfd(it->dir), it->ent->d_name,
str, (size_t)it->sb.st_size) < 0) {
fprintf(stderr, "%s: readlink: %s\n", it->ent->d_name,
strerror(errno));
free(str);
it->state = SQFS_ERROR_INTERNAL;
return it->state;
}
str[it->sb.st_size] = '\0';
*out = str;
return it->state;
fail_ov:
fprintf(stderr, "%s: link target too long\n", it->ent->d_name);
return SQFS_ERROR_OVERFLOW;
}
static int dir_next(dir_iterator_t *base, dir_entry_t **out)
{
unix_dir_iterator_t *it = (unix_dir_iterator_t *)base;
dir_entry_t *decoded;
size_t len;
*out = NULL;
if (it->state != 0)
return it->state;
errno = 0;
it->ent = readdir(it->dir);
if (it->ent == NULL) {
if (errno != 0) {
perror("readdir");
it->state = SQFS_ERROR_INTERNAL;
} else {
it->state = 1;
}
return it->state;
}
if (fstatat(dirfd(it->dir), it->ent->d_name, &it->sb, AT_SYMLINK_NOFOLLOW)) {
perror(it->ent->d_name);
it->state = SQFS_ERROR_INTERNAL;
return it->state;
}
len = strlen(it->ent->d_name);
decoded = alloc_flex(sizeof(*decoded), 1, len + 1);
if (decoded == NULL) {
perror(it->ent->d_name);
it->state = SQFS_ERROR_ALLOC;
return it->state;
}
memcpy(decoded->name, it->ent->d_name, len);
decoded->mtime = it->sb.st_mtime;
decoded->dev = it->sb.st_dev;
decoded->rdev = it->sb.st_rdev;
decoded->uid = it->sb.st_uid;
decoded->gid = it->sb.st_gid;
decoded->mode = it->sb.st_mode;
*out = decoded;
return it->state;
}
static int dir_open_subdir(dir_iterator_t *base, dir_iterator_t **out)
{
const unix_dir_iterator_t *it = (const unix_dir_iterator_t *)base;
unix_dir_iterator_t *sub = NULL;
int fd;
*out = NULL;
if (it->state < 0)
return it->state;
if (it->state > 0 || it->ent == NULL)
return SQFS_ERROR_NO_ENTRY;
fd = openat(dirfd(it->dir), it->ent->d_name, O_RDONLY | O_DIRECTORY);
if (fd < 0) {
if (errno == ENOTDIR)
return SQFS_ERROR_NOT_DIR;
return SQFS_ERROR_IO;
}
sub = calloc(1, sizeof(*sub));
if (sub == NULL)
goto fail_alloc;
sub->dir = fdopendir(fd);
if (sub->dir == NULL)
goto fail_alloc;
if (fstat(dirfd(sub->dir), &sub->sb)) {
free(sub);
return SQFS_ERROR_IO;
}
sqfs_object_init(sub, dir_destroy, NULL);
((dir_iterator_t *)sub)->dev = sub->sb.st_dev;
((dir_iterator_t *)sub)->next = dir_next;
((dir_iterator_t *)sub)->read_link = dir_read_link;
((dir_iterator_t *)sub)->open_subdir = dir_open_subdir;
*out = (dir_iterator_t *)sub;
return 0;
fail_alloc:
free(sub);
close(fd);
return SQFS_ERROR_ALLOC;
}
dir_iterator_t *dir_iterator_create(const char *path)
{
unix_dir_iterator_t *it = calloc(1, sizeof(*it));
if (it == NULL) {
perror(path);
return NULL;
}
it->state = 0;
it->dir = opendir(path);
if (it->dir == NULL) {
perror(path);
free(it);
return NULL;
}
if (fstat(dirfd(it->dir), &it->sb)) {
perror(path);
closedir(it->dir);
free(it);
return NULL;
}
sqfs_object_init(it, dir_destroy, NULL);
((dir_iterator_t *)it)->dev = it->sb.st_dev;
((dir_iterator_t *)it)->next = dir_next;
((dir_iterator_t *)it)->read_link = dir_read_link;
((dir_iterator_t *)it)->open_subdir = dir_open_subdir;
return (dir_iterator_t *)it;
}
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