util-lib: move a number of fs operations into fs-util.[ch]
This commit is contained in:
Lennart Poettering
@@ -0,0 +1,477 @@
|
||||
/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
|
||||
|
||||
/***
|
||||
This file is part of systemd.
|
||||
|
||||
Copyright 2010 Lennart Poettering
|
||||
|
||||
systemd is free software; you can redistribute it and/or modify it
|
||||
under the terms of the GNU Lesser General Public License as published by
|
||||
the Free Software Foundation; either version 2.1 of the License, or
|
||||
(at your option) any later version.
|
||||
|
||||
systemd is distributed in the hope that it will be useful, but
|
||||
WITHOUT ANY WARRANTY; without even the implied warranty of
|
||||
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
|
||||
Lesser General Public License for more details.
|
||||
|
||||
You should have received a copy of the GNU Lesser General Public License
|
||||
along with systemd; If not, see <http://www.gnu.org/licenses/>.
|
||||
***/
|
||||
|
||||
#include "dirent-util.h"
|
||||
#include "fd-util.h"
|
||||
#include "fileio.h"
|
||||
#include "fs-util.h"
|
||||
#include "mkdir.h"
|
||||
#include "path-util.h"
|
||||
#include "string-util.h"
|
||||
#include "strv.h"
|
||||
#include "util.h"
|
||||
|
||||
int unlink_noerrno(const char *path) {
|
||||
PROTECT_ERRNO;
|
||||
int r;
|
||||
|
||||
r = unlink(path);
|
||||
if (r < 0)
|
||||
return -errno;
|
||||
|
||||
return 0;
|
||||
}
|
||||
|
||||
int rmdir_parents(const char *path, const char *stop) {
|
||||
size_t l;
|
||||
int r = 0;
|
||||
|
||||
assert(path);
|
||||
assert(stop);
|
||||
|
||||
l = strlen(path);
|
||||
|
||||
/* Skip trailing slashes */
|
||||
while (l > 0 && path[l-1] == '/')
|
||||
l--;
|
||||
|
||||
while (l > 0) {
|
||||
char *t;
|
||||
|
||||
/* Skip last component */
|
||||
while (l > 0 && path[l-1] != '/')
|
||||
l--;
|
||||
|
||||
/* Skip trailing slashes */
|
||||
while (l > 0 && path[l-1] == '/')
|
||||
l--;
|
||||
|
||||
if (l <= 0)
|
||||
break;
|
||||
|
||||
t = strndup(path, l);
|
||||
if (!t)
|
||||
return -ENOMEM;
|
||||
|
||||
if (path_startswith(stop, t)) {
|
||||
free(t);
|
||||
return 0;
|
||||
}
|
||||
|
||||
r = rmdir(t);
|
||||
free(t);
|
||||
|
||||
if (r < 0)
|
||||
if (errno != ENOENT)
|
||||
return -errno;
|
||||
}
|
||||
|
||||
return 0;
|
||||
}
|
||||
|
||||
|
||||
int rename_noreplace(int olddirfd, const char *oldpath, int newdirfd, const char *newpath) {
|
||||
struct stat buf;
|
||||
int ret;
|
||||
|
||||
ret = renameat2(olddirfd, oldpath, newdirfd, newpath, RENAME_NOREPLACE);
|
||||
if (ret >= 0)
|
||||
return 0;
|
||||
|
||||
/* renameat2() exists since Linux 3.15, btrfs added support for it later.
|
||||
* If it is not implemented, fallback to another method. */
|
||||
if (!IN_SET(errno, EINVAL, ENOSYS))
|
||||
return -errno;
|
||||
|
||||
/* The link()/unlink() fallback does not work on directories. But
|
||||
* renameat() without RENAME_NOREPLACE gives the same semantics on
|
||||
* directories, except when newpath is an *empty* directory. This is
|
||||
* good enough. */
|
||||
ret = fstatat(olddirfd, oldpath, &buf, AT_SYMLINK_NOFOLLOW);
|
||||
if (ret >= 0 && S_ISDIR(buf.st_mode)) {
|
||||
ret = renameat(olddirfd, oldpath, newdirfd, newpath);
|
||||
return ret >= 0 ? 0 : -errno;
|
||||
}
|
||||
|
||||
/* If it is not a directory, use the link()/unlink() fallback. */
|
||||
ret = linkat(olddirfd, oldpath, newdirfd, newpath, 0);
|
||||
if (ret < 0)
|
||||
return -errno;
|
||||
|
||||
ret = unlinkat(olddirfd, oldpath, 0);
|
||||
if (ret < 0) {
|
||||
/* backup errno before the following unlinkat() alters it */
|
||||
ret = errno;
|
||||
(void) unlinkat(newdirfd, newpath, 0);
|
||||
errno = ret;
|
||||
return -errno;
|
||||
}
|
||||
|
||||
return 0;
|
||||
}
|
||||
|
||||
int readlinkat_malloc(int fd, const char *p, char **ret) {
|
||||
size_t l = 100;
|
||||
int r;
|
||||
|
||||
assert(p);
|
||||
assert(ret);
|
||||
|
||||
for (;;) {
|
||||
char *c;
|
||||
ssize_t n;
|
||||
|
||||
c = new(char, l);
|
||||
if (!c)
|
||||
return -ENOMEM;
|
||||
|
||||
n = readlinkat(fd, p, c, l-1);
|
||||
if (n < 0) {
|
||||
r = -errno;
|
||||
free(c);
|
||||
return r;
|
||||
}
|
||||
|
||||
if ((size_t) n < l-1) {
|
||||
c[n] = 0;
|
||||
*ret = c;
|
||||
return 0;
|
||||
}
|
||||
|
||||
free(c);
|
||||
l *= 2;
|
||||
}
|
||||
}
|
||||
|
||||
int readlink_malloc(const char *p, char **ret) {
|
||||
return readlinkat_malloc(AT_FDCWD, p, ret);
|
||||
}
|
||||
|
||||
int readlink_value(const char *p, char **ret) {
|
||||
_cleanup_free_ char *link = NULL;
|
||||
char *value;
|
||||
int r;
|
||||
|
||||
r = readlink_malloc(p, &link);
|
||||
if (r < 0)
|
||||
return r;
|
||||
|
||||
value = basename(link);
|
||||
if (!value)
|
||||
return -ENOENT;
|
||||
|
||||
value = strdup(value);
|
||||
if (!value)
|
||||
return -ENOMEM;
|
||||
|
||||
*ret = value;
|
||||
|
||||
return 0;
|
||||
}
|
||||
|
||||
int readlink_and_make_absolute(const char *p, char **r) {
|
||||
_cleanup_free_ char *target = NULL;
|
||||
char *k;
|
||||
int j;
|
||||
|
||||
assert(p);
|
||||
assert(r);
|
||||
|
||||
j = readlink_malloc(p, &target);
|
||||
if (j < 0)
|
||||
return j;
|
||||
|
||||
k = file_in_same_dir(p, target);
|
||||
if (!k)
|
||||
return -ENOMEM;
|
||||
|
||||
*r = k;
|
||||
return 0;
|
||||
}
|
||||
|
||||
int readlink_and_canonicalize(const char *p, char **r) {
|
||||
char *t, *s;
|
||||
int j;
|
||||
|
||||
assert(p);
|
||||
assert(r);
|
||||
|
||||
j = readlink_and_make_absolute(p, &t);
|
||||
if (j < 0)
|
||||
return j;
|
||||
|
||||
s = canonicalize_file_name(t);
|
||||
if (s) {
|
||||
free(t);
|
||||
*r = s;
|
||||
} else
|
||||
*r = t;
|
||||
|
||||
path_kill_slashes(*r);
|
||||
|
||||
return 0;
|
||||
}
|
||||
|
||||
int chmod_and_chown(const char *path, mode_t mode, uid_t uid, gid_t gid) {
|
||||
assert(path);
|
||||
|
||||
/* Under the assumption that we are running privileged we
|
||||
* first change the access mode and only then hand out
|
||||
* ownership to avoid a window where access is too open. */
|
||||
|
||||
if (mode != MODE_INVALID)
|
||||
if (chmod(path, mode) < 0)
|
||||
return -errno;
|
||||
|
||||
if (uid != UID_INVALID || gid != GID_INVALID)
|
||||
if (chown(path, uid, gid) < 0)
|
||||
return -errno;
|
||||
|
||||
return 0;
|
||||
}
|
||||
|
||||
int fchmod_and_fchown(int fd, mode_t mode, uid_t uid, gid_t gid) {
|
||||
assert(fd >= 0);
|
||||
|
||||
/* Under the assumption that we are running privileged we
|
||||
* first change the access mode and only then hand out
|
||||
* ownership to avoid a window where access is too open. */
|
||||
|
||||
if (mode != MODE_INVALID)
|
||||
if (fchmod(fd, mode) < 0)
|
||||
return -errno;
|
||||
|
||||
if (uid != UID_INVALID || gid != GID_INVALID)
|
||||
if (fchown(fd, uid, gid) < 0)
|
||||
return -errno;
|
||||
|
||||
return 0;
|
||||
}
|
||||
|
||||
int fchmod_umask(int fd, mode_t m) {
|
||||
mode_t u;
|
||||
int r;
|
||||
|
||||
u = umask(0777);
|
||||
r = fchmod(fd, m & (~u)) < 0 ? -errno : 0;
|
||||
umask(u);
|
||||
|
||||
return r;
|
||||
}
|
||||
|
||||
int fd_warn_permissions(const char *path, int fd) {
|
||||
struct stat st;
|
||||
|
||||
if (fstat(fd, &st) < 0)
|
||||
return -errno;
|
||||
|
||||
if (st.st_mode & 0111)
|
||||
log_warning("Configuration file %s is marked executable. Please remove executable permission bits. Proceeding anyway.", path);
|
||||
|
||||
if (st.st_mode & 0002)
|
||||
log_warning("Configuration file %s is marked world-writable. Please remove world writability permission bits. Proceeding anyway.", path);
|
||||
|
||||
if (getpid() == 1 && (st.st_mode & 0044) != 0044)
|
||||
log_warning("Configuration file %s is marked world-inaccessible. This has no effect as configuration data is accessible via APIs without restrictions. Proceeding anyway.", path);
|
||||
|
||||
return 0;
|
||||
}
|
||||
|
||||
int touch_file(const char *path, bool parents, usec_t stamp, uid_t uid, gid_t gid, mode_t mode) {
|
||||
_cleanup_close_ int fd;
|
||||
int r;
|
||||
|
||||
assert(path);
|
||||
|
||||
if (parents)
|
||||
mkdir_parents(path, 0755);
|
||||
|
||||
fd = open(path, O_WRONLY|O_CREAT|O_CLOEXEC|O_NOCTTY, mode > 0 ? mode : 0644);
|
||||
if (fd < 0)
|
||||
return -errno;
|
||||
|
||||
if (mode > 0) {
|
||||
r = fchmod(fd, mode);
|
||||
if (r < 0)
|
||||
return -errno;
|
||||
}
|
||||
|
||||
if (uid != UID_INVALID || gid != GID_INVALID) {
|
||||
r = fchown(fd, uid, gid);
|
||||
if (r < 0)
|
||||
return -errno;
|
||||
}
|
||||
|
||||
if (stamp != USEC_INFINITY) {
|
||||
struct timespec ts[2];
|
||||
|
||||
timespec_store(&ts[0], stamp);
|
||||
ts[1] = ts[0];
|
||||
r = futimens(fd, ts);
|
||||
} else
|
||||
r = futimens(fd, NULL);
|
||||
if (r < 0)
|
||||
return -errno;
|
||||
|
||||
return 0;
|
||||
}
|
||||
|
||||
int touch(const char *path) {
|
||||
return touch_file(path, false, USEC_INFINITY, UID_INVALID, GID_INVALID, 0);
|
||||
}
|
||||
|
||||
int symlink_idempotent(const char *from, const char *to) {
|
||||
_cleanup_free_ char *p = NULL;
|
||||
int r;
|
||||
|
||||
assert(from);
|
||||
assert(to);
|
||||
|
||||
if (symlink(from, to) < 0) {
|
||||
if (errno != EEXIST)
|
||||
return -errno;
|
||||
|
||||
r = readlink_malloc(to, &p);
|
||||
if (r < 0)
|
||||
return r;
|
||||
|
||||
if (!streq(p, from))
|
||||
return -EINVAL;
|
||||
}
|
||||
|
||||
return 0;
|
||||
}
|
||||
|
||||
int symlink_atomic(const char *from, const char *to) {
|
||||
_cleanup_free_ char *t = NULL;
|
||||
int r;
|
||||
|
||||
assert(from);
|
||||
assert(to);
|
||||
|
||||
r = tempfn_random(to, NULL, &t);
|
||||
if (r < 0)
|
||||
return r;
|
||||
|
||||
if (symlink(from, t) < 0)
|
||||
return -errno;
|
||||
|
||||
if (rename(t, to) < 0) {
|
||||
unlink_noerrno(t);
|
||||
return -errno;
|
||||
}
|
||||
|
||||
return 0;
|
||||
}
|
||||
|
||||
int mknod_atomic(const char *path, mode_t mode, dev_t dev) {
|
||||
_cleanup_free_ char *t = NULL;
|
||||
int r;
|
||||
|
||||
assert(path);
|
||||
|
||||
r = tempfn_random(path, NULL, &t);
|
||||
if (r < 0)
|
||||
return r;
|
||||
|
||||
if (mknod(t, mode, dev) < 0)
|
||||
return -errno;
|
||||
|
||||
if (rename(t, path) < 0) {
|
||||
unlink_noerrno(t);
|
||||
return -errno;
|
||||
}
|
||||
|
||||
return 0;
|
||||
}
|
||||
|
||||
int mkfifo_atomic(const char *path, mode_t mode) {
|
||||
_cleanup_free_ char *t = NULL;
|
||||
int r;
|
||||
|
||||
assert(path);
|
||||
|
||||
r = tempfn_random(path, NULL, &t);
|
||||
if (r < 0)
|
||||
return r;
|
||||
|
||||
if (mkfifo(t, mode) < 0)
|
||||
return -errno;
|
||||
|
||||
if (rename(t, path) < 0) {
|
||||
unlink_noerrno(t);
|
||||
return -errno;
|
||||
}
|
||||
|
||||
return 0;
|
||||
}
|
||||
|
||||
int get_files_in_directory(const char *path, char ***list) {
|
||||
_cleanup_closedir_ DIR *d = NULL;
|
||||
size_t bufsize = 0, n = 0;
|
||||
_cleanup_strv_free_ char **l = NULL;
|
||||
|
||||
assert(path);
|
||||
|
||||
/* Returns all files in a directory in *list, and the number
|
||||
* of files as return value. If list is NULL returns only the
|
||||
* number. */
|
||||
|
||||
d = opendir(path);
|
||||
if (!d)
|
||||
return -errno;
|
||||
|
||||
for (;;) {
|
||||
struct dirent *de;
|
||||
|
||||
errno = 0;
|
||||
de = readdir(d);
|
||||
if (!de && errno != 0)
|
||||
return -errno;
|
||||
if (!de)
|
||||
break;
|
||||
|
||||
dirent_ensure_type(d, de);
|
||||
|
||||
if (!dirent_is_file(de))
|
||||
continue;
|
||||
|
||||
if (list) {
|
||||
/* one extra slot is needed for the terminating NULL */
|
||||
if (!GREEDY_REALLOC(l, bufsize, n + 2))
|
||||
return -ENOMEM;
|
||||
|
||||
l[n] = strdup(de->d_name);
|
||||
if (!l[n])
|
||||
return -ENOMEM;
|
||||
|
||||
l[++n] = NULL;
|
||||
} else
|
||||
n++;
|
||||
}
|
||||
|
||||
if (list) {
|
||||
*list = l;
|
||||
l = NULL; /* avoid freeing */
|
||||
}
|
||||
|
||||
return n;
|
||||
}
|
||||
Reference in New Issue
Block a user