src/basic/fs-util.h

/* SPDX-License-Identifier: LGPL-2.1-or-later */
#pragma once

#include <dirent.h>
#include <fcntl.h>
#include <limits.h>
#include <stdbool.h>
#include <stdint.h>
#include <sys/inotify.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <unistd.h>

#include "alloc-util.h"
#include "errno-util.h"
#include "time-util.h"

#define MODE_INVALID ((mode_t) -1)

/* The following macros add 1 when converting things, since 0 is a valid mode, while the pointer
 * NULL is special */
#define PTR_TO_MODE(p) ((mode_t) ((uintptr_t) (p)-1))
#define MODE_TO_PTR(u) ((void *) ((uintptr_t) (u)+1))

int unlink_noerrno(const char *path);

int rmdir_parents(const char *path, const char *stop);

int rename_noreplace(int olddirfd, const char *oldpath, int newdirfd, const char *newpath);

int readlinkat_malloc(int fd, const char *p, char **ret);
int readlink_malloc(const char *p, char **r);
int readlink_value(const char *p, char **ret);
int readlink_and_make_absolute(const char *p, char **r);

int chmod_and_chown(const char *path, mode_t mode, uid_t uid, gid_t gid);
int fchmod_and_chown_with_fallback(int fd, const char *path, mode_t mode, uid_t uid, gid_t gid);
static inline int fchmod_and_chown(int fd, mode_t mode, uid_t uid, gid_t gid) {
        return fchmod_and_chown_with_fallback(fd, NULL, mode, uid, gid); /* no fallback */
}

int fchmod_umask(int fd, mode_t mode);
int fchmod_opath(int fd, mode_t m);

int futimens_opath(int fd, const struct timespec ts[2]);

int fd_warn_permissions(const char *path, int fd);
int stat_warn_permissions(const char *path, const struct stat *st);

#define laccess(path, mode)                                             \
        (faccessat(AT_FDCWD, (path), (mode), AT_SYMLINK_NOFOLLOW) < 0 ? -errno : 0)

int touch_file(const char *path, bool parents, usec_t stamp, uid_t uid, gid_t gid, mode_t mode);
int touch(const char *path);

int symlink_idempotent(const char *from, const char *to, bool make_relative);

int symlink_atomic(const char *from, const char *to);
int mknod_atomic(const char *path, mode_t mode, dev_t dev);
int mkfifo_atomic(const char *path, mode_t mode);
int mkfifoat_atomic(int dir_fd, const char *path, mode_t mode);

int get_files_in_directory(const char *path, char ***list);

int tmp_dir(const char **ret);
int var_tmp_dir(const char **ret);

int unlink_or_warn(const char *filename);

#define INOTIFY_EVENT_MAX (sizeof(struct inotify_event) + NAME_MAX + 1)

#define FOREACH_INOTIFY_EVENT(e, buffer, sz) \
        for ((e) = &buffer.ev;                                \
             (uint8_t*) (e) < (uint8_t*) (buffer.raw) + (sz); \
             (e) = (struct inotify_event*) ((uint8_t*) (e) + sizeof(struct inotify_event) + (e)->len))

union inotify_event_buffer {
        struct inotify_event ev;
        uint8_t raw[INOTIFY_EVENT_MAX];
};

int inotify_add_watch_fd(int fd, int what, uint32_t mask);
int inotify_add_watch_and_warn(int fd, const char *pathname, uint32_t mask);

enum {
        CHASE_PREFIX_ROOT = 1 << 0, /* The specified path will be prefixed by the specified root before beginning the iteration */
        CHASE_NONEXISTENT = 1 << 1, /* It's OK if the path doesn't actually exist. */
        CHASE_NO_AUTOFS   = 1 << 2, /* Return -EREMOTE if autofs mount point found */
        CHASE_SAFE        = 1 << 3, /* Return -EPERM if we ever traverse from unprivileged to privileged files or directories */
        CHASE_TRAIL_SLASH = 1 << 4, /* Any trailing slash will be preserved */
        CHASE_STEP        = 1 << 5, /* Just execute a single step of the normalization */
        CHASE_NOFOLLOW    = 1 << 6, /* Do not follow the path's right-most component. With ret_fd, when the path's
                                     * right-most component refers to symlink, return O_PATH fd of the symlink. */
        CHASE_WARN        = 1 << 7, /* Emit an appropriate warning when an error is encountered */
};

bool unsafe_transition(const struct stat *a, const struct stat *b);

/* How many iterations to execute before returning -ELOOP */
#define CHASE_SYMLINKS_MAX 32

int chase_symlinks(const char *path_with_prefix, const char *root, unsigned flags, char **ret_path, int *ret_fd);

int chase_symlinks_and_open(const char *path, const char *root, unsigned chase_flags, int open_flags, char **ret_path);
int chase_symlinks_and_opendir(const char *path, const char *root, unsigned chase_flags, char **ret_path, DIR **ret_dir);
int chase_symlinks_and_stat(const char *path, const char *root, unsigned chase_flags, char **ret_path, struct stat *ret_stat, int *ret_fd);

/* Useful for usage with _cleanup_(), removes a directory and frees the pointer */
static inline char *rmdir_and_free(char *p) {
        PROTECT_ERRNO;

        if (!p)
                return NULL;

        (void) rmdir(p);
        return mfree(p);
}
DEFINE_TRIVIAL_CLEANUP_FUNC(char*, rmdir_and_free);

static inline char* unlink_and_free(char *p) {
        if (!p)
                return NULL;

        (void) unlink_noerrno(p);
        return mfree(p);
}
DEFINE_TRIVIAL_CLEANUP_FUNC(char*, unlink_and_free);

int access_fd(int fd, int mode);

void unlink_tempfilep(char (*p)[]);

typedef enum UnlinkDeallocateFlags {
        UNLINK_REMOVEDIR = 1 << 0,
        UNLINK_ERASE     = 1 << 1,
} UnlinkDeallocateFlags;

int unlinkat_deallocate(int fd, const char *name, UnlinkDeallocateFlags flags);

int fsync_directory_of_file(int fd);
int fsync_full(int fd);
int fsync_path_at(int at_fd, const char *path);

int syncfs_path(int atfd, const char *path);

int open_parent(const char *path, int flags, mode_t mode);

int conservative_renameat(int olddirfd, const char *oldpath, int newdirfd, const char *newpath);
static inline int conservative_rename(const char *oldpath, const char *newpath) {
        return conservative_renameat(AT_FDCWD, oldpath, AT_FDCWD, newpath);
}

int posix_fallocate_loop(int fd, uint64_t offset, uint64_t size);