1616 lines
55 KiB
C
1616 lines
55 KiB
C
/* SPDX-License-Identifier: LGPL-2.1-or-later */
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#include <errno.h>
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#include <stddef.h>
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#include <stdlib.h>
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#include <linux/falloc.h>
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#include <linux/magic.h>
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#include <unistd.h>
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#include "alloc-util.h"
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#include "blockdev-util.h"
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#include "dirent-util.h"
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#include "fd-util.h"
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#include "fileio.h"
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#include "fs-util.h"
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#include "locale-util.h"
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#include "log.h"
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#include "macro.h"
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#include "missing_fcntl.h"
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#include "missing_fs.h"
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#include "missing_syscall.h"
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#include "mkdir.h"
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#include "parse-util.h"
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#include "path-util.h"
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#include "process-util.h"
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#include "random-util.h"
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#include "stat-util.h"
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#include "stdio-util.h"
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#include "string-util.h"
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#include "strv.h"
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#include "time-util.h"
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#include "tmpfile-util.h"
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#include "user-util.h"
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#include "util.h"
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int unlink_noerrno(const char *path) {
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PROTECT_ERRNO;
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int r;
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r = unlink(path);
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if (r < 0)
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return -errno;
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return 0;
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}
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int rmdir_parents(const char *path, const char *stop) {
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size_t l;
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int r = 0;
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assert(path);
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assert(stop);
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l = strlen(path);
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/* Skip trailing slashes */
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while (l > 0 && path[l-1] == '/')
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l--;
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while (l > 0) {
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char *t;
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/* Skip last component */
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while (l > 0 && path[l-1] != '/')
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l--;
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/* Skip trailing slashes */
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while (l > 0 && path[l-1] == '/')
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l--;
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if (l <= 0)
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break;
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t = strndup(path, l);
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if (!t)
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return -ENOMEM;
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if (path_startswith(stop, t)) {
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free(t);
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return 0;
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}
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r = rmdir(t);
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free(t);
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if (r < 0)
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if (errno != ENOENT)
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return -errno;
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}
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return 0;
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}
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int rename_noreplace(int olddirfd, const char *oldpath, int newdirfd, const char *newpath) {
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int r;
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/* Try the ideal approach first */
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if (renameat2(olddirfd, oldpath, newdirfd, newpath, RENAME_NOREPLACE) >= 0)
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return 0;
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/* renameat2() exists since Linux 3.15, btrfs and FAT added support for it later. If it is not implemented,
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* fall back to a different method. */
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if (!IN_SET(errno, EINVAL, ENOSYS, ENOTTY))
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return -errno;
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/* Let's try to use linkat()+unlinkat() as fallback. This doesn't work on directories and on some file systems
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* that do not support hard links (such as FAT, most prominently), but for files it's pretty close to what we
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* want — though not atomic (i.e. for a short period both the new and the old filename will exist). */
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if (linkat(olddirfd, oldpath, newdirfd, newpath, 0) >= 0) {
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if (unlinkat(olddirfd, oldpath, 0) < 0) {
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r = -errno; /* Backup errno before the following unlinkat() alters it */
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(void) unlinkat(newdirfd, newpath, 0);
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return r;
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}
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return 0;
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}
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if (!IN_SET(errno, EINVAL, ENOSYS, ENOTTY, EPERM)) /* FAT returns EPERM on link()… */
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return -errno;
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/* OK, neither RENAME_NOREPLACE nor linkat()+unlinkat() worked. Let's then fall back to the racy TOCTOU
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* vulnerable accessat(F_OK) check followed by classic, replacing renameat(), we have nothing better. */
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if (faccessat(newdirfd, newpath, F_OK, AT_SYMLINK_NOFOLLOW) >= 0)
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return -EEXIST;
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if (errno != ENOENT)
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return -errno;
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if (renameat(olddirfd, oldpath, newdirfd, newpath) < 0)
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return -errno;
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return 0;
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}
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int readlinkat_malloc(int fd, const char *p, char **ret) {
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size_t l = FILENAME_MAX+1;
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int r;
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assert(p);
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assert(ret);
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for (;;) {
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char *c;
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ssize_t n;
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c = new(char, l);
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if (!c)
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return -ENOMEM;
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n = readlinkat(fd, p, c, l-1);
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if (n < 0) {
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r = -errno;
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free(c);
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return r;
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}
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if ((size_t) n < l-1) {
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c[n] = 0;
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*ret = c;
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return 0;
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}
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free(c);
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l *= 2;
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}
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}
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int readlink_malloc(const char *p, char **ret) {
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return readlinkat_malloc(AT_FDCWD, p, ret);
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}
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int readlink_value(const char *p, char **ret) {
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_cleanup_free_ char *link = NULL;
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char *value;
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int r;
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r = readlink_malloc(p, &link);
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if (r < 0)
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return r;
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value = basename(link);
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if (!value)
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return -ENOENT;
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value = strdup(value);
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if (!value)
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return -ENOMEM;
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*ret = value;
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return 0;
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}
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int readlink_and_make_absolute(const char *p, char **r) {
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_cleanup_free_ char *target = NULL;
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char *k;
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int j;
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assert(p);
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assert(r);
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j = readlink_malloc(p, &target);
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if (j < 0)
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return j;
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k = file_in_same_dir(p, target);
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if (!k)
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return -ENOMEM;
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*r = k;
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return 0;
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}
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int chmod_and_chown(const char *path, mode_t mode, uid_t uid, gid_t gid) {
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_cleanup_close_ int fd = -1;
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assert(path);
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fd = open(path, O_PATH|O_CLOEXEC|O_NOFOLLOW); /* Let's acquire an O_PATH fd, as precaution to change
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* mode/owner on the same file */
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if (fd < 0)
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return -errno;
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return fchmod_and_chown(fd, mode, uid, gid);
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}
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int fchmod_and_chown(int fd, mode_t mode, uid_t uid, gid_t gid) {
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bool do_chown, do_chmod;
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struct stat st;
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int r;
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/* Change ownership and access mode of the specified fd. Tries to do so safely, ensuring that at no
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* point in time the access mode is above the old access mode under the old ownership or the new
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* access mode under the new ownership. Note: this call tries hard to leave the access mode
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* unaffected if the uid/gid is changed, i.e. it undoes implicit suid/sgid dropping the kernel does
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* on chown().
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*
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* This call is happy with O_PATH fds. */
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if (fstat(fd, &st) < 0)
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return -errno;
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do_chown =
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(uid != UID_INVALID && st.st_uid != uid) ||
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(gid != GID_INVALID && st.st_gid != gid);
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do_chmod =
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!S_ISLNK(st.st_mode) && /* chmod is not defined on symlinks */
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((mode != MODE_INVALID && ((st.st_mode ^ mode) & 07777) != 0) ||
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do_chown); /* If we change ownership, make sure we reset the mode afterwards, since chown()
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* modifies the access mode too */
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if (mode == MODE_INVALID)
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mode = st.st_mode; /* If we only shall do a chown(), save original mode, since chown() might break it. */
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else if ((mode & S_IFMT) != 0 && ((mode ^ st.st_mode) & S_IFMT) != 0)
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return -EINVAL; /* insist on the right file type if it was specified */
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if (do_chown && do_chmod) {
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mode_t minimal = st.st_mode & mode; /* the subset of the old and the new mask */
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if (((minimal ^ st.st_mode) & 07777) != 0) {
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r = fchmod_opath(fd, minimal & 07777);
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if (r < 0)
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return r;
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}
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}
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if (do_chown)
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if (fchownat(fd, "", uid, gid, AT_EMPTY_PATH) < 0)
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return -errno;
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if (do_chmod) {
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r = fchmod_opath(fd, mode & 07777);
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if (r < 0)
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return r;
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}
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return do_chown || do_chmod;
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}
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int fchmod_umask(int fd, mode_t m) {
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mode_t u;
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int r;
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u = umask(0777);
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r = fchmod(fd, m & (~u)) < 0 ? -errno : 0;
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umask(u);
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return r;
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}
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int fchmod_opath(int fd, mode_t m) {
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char procfs_path[STRLEN("/proc/self/fd/") + DECIMAL_STR_MAX(int)];
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/* This function operates also on fd that might have been opened with
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* O_PATH. Indeed fchmodat() doesn't have the AT_EMPTY_PATH flag like
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* fchownat() does. */
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xsprintf(procfs_path, "/proc/self/fd/%i", fd);
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if (chmod(procfs_path, m) < 0) {
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if (errno != ENOENT)
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return -errno;
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if (proc_mounted() == 0)
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return -ENOSYS; /* if we have no /proc/, the concept is not implementable */
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return -ENOENT;
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}
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return 0;
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}
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int futimens_opath(int fd, const struct timespec ts[2]) {
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char procfs_path[STRLEN("/proc/self/fd/") + DECIMAL_STR_MAX(int)];
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/* Similar to fchmod_path() but for futimens() */
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xsprintf(procfs_path, "/proc/self/fd/%i", fd);
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if (utimensat(AT_FDCWD, procfs_path, ts, 0) < 0) {
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if (errno != ENOENT)
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return -errno;
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if (proc_mounted() == 0)
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return -ENOSYS; /* if we have no /proc/, the concept is not implementable */
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return -ENOENT;
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}
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return 0;
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}
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int stat_warn_permissions(const char *path, const struct stat *st) {
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assert(path);
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assert(st);
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/* Don't complain if we are reading something that is not a file, for example /dev/null */
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if (!S_ISREG(st->st_mode))
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return 0;
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if (st->st_mode & 0111)
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log_warning("Configuration file %s is marked executable. Please remove executable permission bits. Proceeding anyway.", path);
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if (st->st_mode & 0002)
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log_warning("Configuration file %s is marked world-writable. Please remove world writability permission bits. Proceeding anyway.", path);
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if (getpid_cached() == 1 && (st->st_mode & 0044) != 0044)
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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);
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return 0;
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}
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int fd_warn_permissions(const char *path, int fd) {
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struct stat st;
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assert(path);
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assert(fd >= 0);
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if (fstat(fd, &st) < 0)
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return -errno;
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return stat_warn_permissions(path, &st);
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}
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int touch_file(const char *path, bool parents, usec_t stamp, uid_t uid, gid_t gid, mode_t mode) {
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char fdpath[STRLEN("/proc/self/fd/") + DECIMAL_STR_MAX(int)];
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_cleanup_close_ int fd = -1;
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int r, ret = 0;
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assert(path);
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/* Note that touch_file() does not follow symlinks: if invoked on an existing symlink, then it is the symlink
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* itself which is updated, not its target
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*
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* Returns the first error we encounter, but tries to apply as much as possible. */
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if (parents)
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(void) mkdir_parents(path, 0755);
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/* Initially, we try to open the node with O_PATH, so that we get a reference to the node. This is useful in
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* case the path refers to an existing device or socket node, as we can open it successfully in all cases, and
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* won't trigger any driver magic or so. */
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fd = open(path, O_PATH|O_CLOEXEC|O_NOFOLLOW);
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if (fd < 0) {
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if (errno != ENOENT)
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return -errno;
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/* if the node doesn't exist yet, we create it, but with O_EXCL, so that we only create a regular file
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* here, and nothing else */
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fd = open(path, O_WRONLY|O_CREAT|O_EXCL|O_CLOEXEC, IN_SET(mode, 0, MODE_INVALID) ? 0644 : mode);
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if (fd < 0)
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return -errno;
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}
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/* Let's make a path from the fd, and operate on that. With this logic, we can adjust the access mode,
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* ownership and time of the file node in all cases, even if the fd refers to an O_PATH object — which is
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* something fchown(), fchmod(), futimensat() don't allow. */
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xsprintf(fdpath, "/proc/self/fd/%i", fd);
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ret = fchmod_and_chown(fd, mode, uid, gid);
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if (stamp != USEC_INFINITY) {
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struct timespec ts[2];
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timespec_store(&ts[0], stamp);
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ts[1] = ts[0];
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r = utimensat(AT_FDCWD, fdpath, ts, 0);
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} else
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r = utimensat(AT_FDCWD, fdpath, NULL, 0);
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if (r < 0 && ret >= 0)
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return -errno;
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return ret;
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}
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int touch(const char *path) {
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return touch_file(path, false, USEC_INFINITY, UID_INVALID, GID_INVALID, MODE_INVALID);
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}
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int symlink_idempotent(const char *from, const char *to, bool make_relative) {
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_cleanup_free_ char *relpath = NULL;
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int r;
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assert(from);
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assert(to);
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if (make_relative) {
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_cleanup_free_ char *parent = NULL;
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parent = dirname_malloc(to);
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if (!parent)
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return -ENOMEM;
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r = path_make_relative(parent, from, &relpath);
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if (r < 0)
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return r;
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from = relpath;
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}
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if (symlink(from, to) < 0) {
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_cleanup_free_ char *p = NULL;
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|
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if (errno != EEXIST)
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return -errno;
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r = readlink_malloc(to, &p);
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if (r == -EINVAL) /* Not a symlink? In that case return the original error we encountered: -EEXIST */
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return -EEXIST;
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if (r < 0) /* Any other error? In that case propagate it as is */
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return r;
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if (!streq(p, from)) /* Not the symlink we want it to be? In that case, propagate the original -EEXIST */
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return -EEXIST;
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}
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return 0;
|
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}
|
||
|
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int symlink_atomic(const char *from, const char *to) {
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_cleanup_free_ char *t = NULL;
|
||
int r;
|
||
|
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assert(from);
|
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assert(to);
|
||
|
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r = tempfn_random(to, NULL, &t);
|
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if (r < 0)
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return r;
|
||
|
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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) {
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_cleanup_free_ char *t = NULL;
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||
int r;
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||
|
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assert(path);
|
||
|
||
r = tempfn_random(path, NULL, &t);
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if (r < 0)
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||
return r;
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||
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if (mknod(t, mode, dev) < 0)
|
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return -errno;
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||
|
||
if (rename(t, path) < 0) {
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unlink_noerrno(t);
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return -errno;
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}
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return 0;
|
||
}
|
||
|
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int mkfifo_atomic(const char *path, mode_t mode) {
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_cleanup_free_ char *t = NULL;
|
||
int r;
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||
|
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assert(path);
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||
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r = tempfn_random(path, NULL, &t);
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if (r < 0)
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return r;
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||
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if (mkfifo(t, mode) < 0)
|
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return -errno;
|
||
|
||
if (rename(t, path) < 0) {
|
||
unlink_noerrno(t);
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||
return -errno;
|
||
}
|
||
|
||
return 0;
|
||
}
|
||
|
||
int mkfifoat_atomic(int dirfd, const char *path, mode_t mode) {
|
||
_cleanup_free_ char *t = NULL;
|
||
int r;
|
||
|
||
assert(path);
|
||
|
||
if (path_is_absolute(path))
|
||
return mkfifo_atomic(path, mode);
|
||
|
||
/* We're only interested in the (random) filename. */
|
||
r = tempfn_random_child("", NULL, &t);
|
||
if (r < 0)
|
||
return r;
|
||
|
||
if (mkfifoat(dirfd, t, mode) < 0)
|
||
return -errno;
|
||
|
||
if (renameat(dirfd, t, dirfd, path) < 0) {
|
||
unlink_noerrno(t);
|
||
return -errno;
|
||
}
|
||
|
||
return 0;
|
||
}
|
||
|
||
int get_files_in_directory(const char *path, char ***list) {
|
||
_cleanup_closedir_ DIR *d = NULL;
|
||
struct dirent *de;
|
||
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;
|
||
|
||
FOREACH_DIRENT_ALL(de, d, return -errno) {
|
||
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 = TAKE_PTR(l);
|
||
|
||
return n;
|
||
}
|
||
|
||
static int getenv_tmp_dir(const char **ret_path) {
|
||
const char *n;
|
||
int r, ret = 0;
|
||
|
||
assert(ret_path);
|
||
|
||
/* We use the same order of environment variables python uses in tempfile.gettempdir():
|
||
* https://docs.python.org/3/library/tempfile.html#tempfile.gettempdir */
|
||
FOREACH_STRING(n, "TMPDIR", "TEMP", "TMP") {
|
||
const char *e;
|
||
|
||
e = secure_getenv(n);
|
||
if (!e)
|
||
continue;
|
||
if (!path_is_absolute(e)) {
|
||
r = -ENOTDIR;
|
||
goto next;
|
||
}
|
||
if (!path_is_normalized(e)) {
|
||
r = -EPERM;
|
||
goto next;
|
||
}
|
||
|
||
r = is_dir(e, true);
|
||
if (r < 0)
|
||
goto next;
|
||
if (r == 0) {
|
||
r = -ENOTDIR;
|
||
goto next;
|
||
}
|
||
|
||
*ret_path = e;
|
||
return 1;
|
||
|
||
next:
|
||
/* Remember first error, to make this more debuggable */
|
||
if (ret >= 0)
|
||
ret = r;
|
||
}
|
||
|
||
if (ret < 0)
|
||
return ret;
|
||
|
||
*ret_path = NULL;
|
||
return ret;
|
||
}
|
||
|
||
static int tmp_dir_internal(const char *def, const char **ret) {
|
||
const char *e;
|
||
int r, k;
|
||
|
||
assert(def);
|
||
assert(ret);
|
||
|
||
r = getenv_tmp_dir(&e);
|
||
if (r > 0) {
|
||
*ret = e;
|
||
return 0;
|
||
}
|
||
|
||
k = is_dir(def, true);
|
||
if (k == 0)
|
||
k = -ENOTDIR;
|
||
if (k < 0)
|
||
return r < 0 ? r : k;
|
||
|
||
*ret = def;
|
||
return 0;
|
||
}
|
||
|
||
int var_tmp_dir(const char **ret) {
|
||
|
||
/* Returns the location for "larger" temporary files, that is backed by physical storage if available, and thus
|
||
* even might survive a boot: /var/tmp. If $TMPDIR (or related environment variables) are set, its value is
|
||
* returned preferably however. Note that both this function and tmp_dir() below are affected by $TMPDIR,
|
||
* making it a variable that overrides all temporary file storage locations. */
|
||
|
||
return tmp_dir_internal("/var/tmp", ret);
|
||
}
|
||
|
||
int tmp_dir(const char **ret) {
|
||
|
||
/* Similar to var_tmp_dir() above, but returns the location for "smaller" temporary files, which is usually
|
||
* backed by an in-memory file system: /tmp. */
|
||
|
||
return tmp_dir_internal("/tmp", ret);
|
||
}
|
||
|
||
int unlink_or_warn(const char *filename) {
|
||
if (unlink(filename) < 0 && errno != ENOENT)
|
||
/* If the file doesn't exist and the fs simply was read-only (in which
|
||
* case unlink() returns EROFS even if the file doesn't exist), don't
|
||
* complain */
|
||
if (errno != EROFS || access(filename, F_OK) >= 0)
|
||
return log_error_errno(errno, "Failed to remove \"%s\": %m", filename);
|
||
|
||
return 0;
|
||
}
|
||
|
||
int inotify_add_watch_fd(int fd, int what, uint32_t mask) {
|
||
char path[STRLEN("/proc/self/fd/") + DECIMAL_STR_MAX(int) + 1];
|
||
int wd;
|
||
|
||
/* This is like inotify_add_watch(), except that the file to watch is not referenced by a path, but by an fd */
|
||
xsprintf(path, "/proc/self/fd/%i", what);
|
||
|
||
wd = inotify_add_watch(fd, path, mask);
|
||
if (wd < 0)
|
||
return -errno;
|
||
|
||
return wd;
|
||
}
|
||
|
||
int inotify_add_watch_and_warn(int fd, const char *pathname, uint32_t mask) {
|
||
int wd;
|
||
|
||
wd = inotify_add_watch(fd, pathname, mask);
|
||
if (wd < 0) {
|
||
if (errno == ENOSPC)
|
||
return log_error_errno(errno, "Failed to add a watch for %s: inotify watch limit reached", pathname);
|
||
|
||
return log_error_errno(errno, "Failed to add a watch for %s: %m", pathname);
|
||
}
|
||
|
||
return wd;
|
||
}
|
||
|
||
static bool unsafe_transition(const struct stat *a, const struct stat *b) {
|
||
/* Returns true if the transition from a to b is safe, i.e. that we never transition from unprivileged to
|
||
* privileged files or directories. Why bother? So that unprivileged code can't symlink to privileged files
|
||
* making us believe we read something safe even though it isn't safe in the specific context we open it in. */
|
||
|
||
if (a->st_uid == 0) /* Transitioning from privileged to unprivileged is always fine */
|
||
return false;
|
||
|
||
return a->st_uid != b->st_uid; /* Otherwise we need to stay within the same UID */
|
||
}
|
||
|
||
static int log_unsafe_transition(int a, int b, const char *path, unsigned flags) {
|
||
_cleanup_free_ char *n1 = NULL, *n2 = NULL;
|
||
|
||
if (!FLAGS_SET(flags, CHASE_WARN))
|
||
return -ENOLINK;
|
||
|
||
(void) fd_get_path(a, &n1);
|
||
(void) fd_get_path(b, &n2);
|
||
|
||
return log_warning_errno(SYNTHETIC_ERRNO(ENOLINK),
|
||
"Detected unsafe path transition %s %s %s during canonicalization of %s.",
|
||
strna(n1), special_glyph(SPECIAL_GLYPH_ARROW), strna(n2), path);
|
||
}
|
||
|
||
static int log_autofs_mount_point(int fd, const char *path, unsigned flags) {
|
||
_cleanup_free_ char *n1 = NULL;
|
||
|
||
if (!FLAGS_SET(flags, CHASE_WARN))
|
||
return -EREMOTE;
|
||
|
||
(void) fd_get_path(fd, &n1);
|
||
|
||
return log_warning_errno(SYNTHETIC_ERRNO(EREMOTE),
|
||
"Detected autofs mount point %s during canonicalization of %s.",
|
||
strna(n1), path);
|
||
}
|
||
|
||
int chase_symlinks(const char *path, const char *original_root, unsigned flags, char **ret_path, int *ret_fd) {
|
||
_cleanup_free_ char *buffer = NULL, *done = NULL, *root = NULL;
|
||
_cleanup_close_ int fd = -1;
|
||
unsigned max_follow = CHASE_SYMLINKS_MAX; /* how many symlinks to follow before giving up and returning ELOOP */
|
||
struct stat previous_stat;
|
||
bool exists = true;
|
||
char *todo;
|
||
int r;
|
||
|
||
assert(path);
|
||
|
||
/* Either the file may be missing, or we return an fd to the final object, but both make no sense */
|
||
if ((flags & CHASE_NONEXISTENT) && ret_fd)
|
||
return -EINVAL;
|
||
|
||
if ((flags & CHASE_STEP) && ret_fd)
|
||
return -EINVAL;
|
||
|
||
if (isempty(path))
|
||
return -EINVAL;
|
||
|
||
/* This is a lot like canonicalize_file_name(), but takes an additional "root" parameter, that allows following
|
||
* symlinks relative to a root directory, instead of the root of the host.
|
||
*
|
||
* Note that "root" primarily matters if we encounter an absolute symlink. It is also used when following
|
||
* relative symlinks to ensure they cannot be used to "escape" the root directory. The path parameter passed is
|
||
* assumed to be already prefixed by it, except if the CHASE_PREFIX_ROOT flag is set, in which case it is first
|
||
* prefixed accordingly.
|
||
*
|
||
* Algorithmically this operates on two path buffers: "done" are the components of the path we already
|
||
* processed and resolved symlinks, "." and ".." of. "todo" are the components of the path we still need to
|
||
* process. On each iteration, we move one component from "todo" to "done", processing it's special meaning
|
||
* each time. The "todo" path always starts with at least one slash, the "done" path always ends in no
|
||
* slash. We always keep an O_PATH fd to the component we are currently processing, thus keeping lookup races
|
||
* to a minimum.
|
||
*
|
||
* Suggested usage: whenever you want to canonicalize a path, use this function. Pass the absolute path you got
|
||
* as-is: fully qualified and relative to your host's root. Optionally, specify the root parameter to tell this
|
||
* function what to do when encountering a symlink with an absolute path as directory: prefix it by the
|
||
* specified path.
|
||
*
|
||
* There are five ways to invoke this function:
|
||
*
|
||
* 1. Without CHASE_STEP or ret_fd: in this case the path is resolved and the normalized path is
|
||
* returned in `ret_path`. The return value is < 0 on error. If CHASE_NONEXISTENT is also set, 0
|
||
* is returned if the file doesn't exist, > 0 otherwise. If CHASE_NONEXISTENT is not set, >= 0 is
|
||
* returned if the destination was found, -ENOENT if it wasn't.
|
||
*
|
||
* 2. With ret_fd: in this case the destination is opened after chasing it as O_PATH and this file
|
||
* descriptor is returned as return value. This is useful to open files relative to some root
|
||
* directory. Note that the returned O_PATH file descriptors must be converted into a regular one (using
|
||
* fd_reopen() or such) before it can be used for reading/writing. ret_fd may not be combined with
|
||
* CHASE_NONEXISTENT.
|
||
*
|
||
* 3. With CHASE_STEP: in this case only a single step of the normalization is executed, i.e. only the first
|
||
* symlink or ".." component of the path is resolved, and the resulting path is returned. This is useful if
|
||
* a caller wants to trace the path through the file system verbosely. Returns < 0 on error, > 0 if the
|
||
* path is fully normalized, and == 0 for each normalization step. This may be combined with
|
||
* CHASE_NONEXISTENT, in which case 1 is returned when a component is not found.
|
||
*
|
||
* 4. With CHASE_SAFE: in this case the path must not contain unsafe transitions, i.e. transitions from
|
||
* unprivileged to privileged files or directories. In such cases the return value is -ENOLINK. If
|
||
* CHASE_WARN is also set, a warning describing the unsafe transition is emitted.
|
||
*
|
||
* 5. With CHASE_NO_AUTOFS: in this case if an autofs mount point is encountered, path normalization
|
||
* is aborted and -EREMOTE is returned. If CHASE_WARN is also set, a warning showing the path of
|
||
* the mount point is emitted.
|
||
*/
|
||
|
||
/* A root directory of "/" or "" is identical to none */
|
||
if (empty_or_root(original_root))
|
||
original_root = NULL;
|
||
|
||
if (!original_root && !ret_path && !(flags & (CHASE_NONEXISTENT|CHASE_NO_AUTOFS|CHASE_SAFE|CHASE_STEP)) && ret_fd) {
|
||
/* Shortcut the ret_fd case if the caller isn't interested in the actual path and has no root set
|
||
* and doesn't care about any of the other special features we provide either. */
|
||
r = open(path, O_PATH|O_CLOEXEC|((flags & CHASE_NOFOLLOW) ? O_NOFOLLOW : 0));
|
||
if (r < 0)
|
||
return -errno;
|
||
|
||
*ret_fd = r;
|
||
return 0;
|
||
}
|
||
|
||
if (original_root) {
|
||
r = path_make_absolute_cwd(original_root, &root);
|
||
if (r < 0)
|
||
return r;
|
||
|
||
/* Simplify the root directory, so that it has no duplicate slashes and nothing at the
|
||
* end. While we won't resolve the root path we still simplify it. Note that dropping the
|
||
* trailing slash should not change behaviour, since when opening it we specify O_DIRECTORY
|
||
* anyway. Moreover at the end of this function after processing everything we'll always turn
|
||
* the empty string back to "/". */
|
||
delete_trailing_chars(root, "/");
|
||
path_simplify(root, true);
|
||
|
||
if (flags & CHASE_PREFIX_ROOT) {
|
||
/* We don't support relative paths in combination with a root directory */
|
||
if (!path_is_absolute(path))
|
||
return -EINVAL;
|
||
|
||
path = prefix_roota(root, path);
|
||
}
|
||
}
|
||
|
||
r = path_make_absolute_cwd(path, &buffer);
|
||
if (r < 0)
|
||
return r;
|
||
|
||
fd = open(root ?: "/", O_CLOEXEC|O_DIRECTORY|O_PATH);
|
||
if (fd < 0)
|
||
return -errno;
|
||
|
||
if (flags & CHASE_SAFE) {
|
||
if (fstat(fd, &previous_stat) < 0)
|
||
return -errno;
|
||
}
|
||
|
||
if (root) {
|
||
_cleanup_free_ char *absolute = NULL;
|
||
const char *e;
|
||
|
||
/* If we are operating on a root directory, let's take the root directory as it is. */
|
||
|
||
e = path_startswith(buffer, root);
|
||
if (!e)
|
||
return log_full_errno(flags & CHASE_WARN ? LOG_WARNING : LOG_DEBUG,
|
||
SYNTHETIC_ERRNO(ECHRNG),
|
||
"Specified path '%s' is outside of specified root directory '%s', refusing to resolve.",
|
||
path, root);
|
||
|
||
done = strdup(root);
|
||
if (!done)
|
||
return -ENOMEM;
|
||
|
||
/* Make sure "todo" starts with a slash */
|
||
absolute = strjoin("/", e);
|
||
if (!absolute)
|
||
return -ENOMEM;
|
||
|
||
free_and_replace(buffer, absolute);
|
||
}
|
||
|
||
todo = buffer;
|
||
for (;;) {
|
||
_cleanup_free_ char *first = NULL;
|
||
_cleanup_close_ int child = -1;
|
||
struct stat st;
|
||
size_t n, m;
|
||
|
||
/* Determine length of first component in the path */
|
||
n = strspn(todo, "/"); /* The slashes */
|
||
|
||
if (n > 1) {
|
||
/* If we are looking at more than a single slash then skip all but one, so that when
|
||
* we are done with everything we have a normalized path with only single slashes
|
||
* separating the path components. */
|
||
todo += n - 1;
|
||
n = 1;
|
||
}
|
||
|
||
m = n + strcspn(todo + n, "/"); /* The entire length of the component */
|
||
|
||
/* Extract the first component. */
|
||
first = strndup(todo, m);
|
||
if (!first)
|
||
return -ENOMEM;
|
||
|
||
todo += m;
|
||
|
||
/* Empty? Then we reached the end. */
|
||
if (isempty(first))
|
||
break;
|
||
|
||
/* Just a single slash? Then we reached the end. */
|
||
if (path_equal(first, "/")) {
|
||
/* Preserve the trailing slash */
|
||
|
||
if (flags & CHASE_TRAIL_SLASH)
|
||
if (!strextend(&done, "/", NULL))
|
||
return -ENOMEM;
|
||
|
||
break;
|
||
}
|
||
|
||
/* Just a dot? Then let's eat this up. */
|
||
if (path_equal(first, "/."))
|
||
continue;
|
||
|
||
/* Two dots? Then chop off the last bit of what we already found out. */
|
||
if (path_equal(first, "/..")) {
|
||
_cleanup_free_ char *parent = NULL;
|
||
_cleanup_close_ int fd_parent = -1;
|
||
|
||
/* If we already are at the top, then going up will not change anything. This is in-line with
|
||
* how the kernel handles this. */
|
||
if (empty_or_root(done))
|
||
continue;
|
||
|
||
parent = dirname_malloc(done);
|
||
if (!parent)
|
||
return -ENOMEM;
|
||
|
||
/* Don't allow this to leave the root dir. */
|
||
if (root &&
|
||
path_startswith(done, root) &&
|
||
!path_startswith(parent, root))
|
||
continue;
|
||
|
||
free_and_replace(done, parent);
|
||
|
||
if (flags & CHASE_STEP)
|
||
goto chased_one;
|
||
|
||
fd_parent = openat(fd, "..", O_CLOEXEC|O_NOFOLLOW|O_PATH);
|
||
if (fd_parent < 0)
|
||
return -errno;
|
||
|
||
if (flags & CHASE_SAFE) {
|
||
if (fstat(fd_parent, &st) < 0)
|
||
return -errno;
|
||
|
||
if (unsafe_transition(&previous_stat, &st))
|
||
return log_unsafe_transition(fd, fd_parent, path, flags);
|
||
|
||
previous_stat = st;
|
||
}
|
||
|
||
safe_close(fd);
|
||
fd = TAKE_FD(fd_parent);
|
||
|
||
continue;
|
||
}
|
||
|
||
/* Otherwise let's see what this is. */
|
||
child = openat(fd, first + n, O_CLOEXEC|O_NOFOLLOW|O_PATH);
|
||
if (child < 0) {
|
||
|
||
if (errno == ENOENT &&
|
||
(flags & CHASE_NONEXISTENT) &&
|
||
(isempty(todo) || path_is_normalized(todo))) {
|
||
|
||
/* If CHASE_NONEXISTENT is set, and the path does not exist, then that's OK, return
|
||
* what we got so far. But don't allow this if the remaining path contains "../ or "./"
|
||
* or something else weird. */
|
||
|
||
/* If done is "/", as first also contains slash at the head, then remove this redundant slash. */
|
||
if (streq_ptr(done, "/"))
|
||
*done = '\0';
|
||
|
||
if (!strextend(&done, first, todo, NULL))
|
||
return -ENOMEM;
|
||
|
||
exists = false;
|
||
break;
|
||
}
|
||
|
||
return -errno;
|
||
}
|
||
|
||
if (fstat(child, &st) < 0)
|
||
return -errno;
|
||
if ((flags & CHASE_SAFE) &&
|
||
unsafe_transition(&previous_stat, &st))
|
||
return log_unsafe_transition(fd, child, path, flags);
|
||
|
||
previous_stat = st;
|
||
|
||
if ((flags & CHASE_NO_AUTOFS) &&
|
||
fd_is_fs_type(child, AUTOFS_SUPER_MAGIC) > 0)
|
||
return log_autofs_mount_point(child, path, flags);
|
||
|
||
if (S_ISLNK(st.st_mode) && !((flags & CHASE_NOFOLLOW) && isempty(todo))) {
|
||
char *joined;
|
||
_cleanup_free_ char *destination = NULL;
|
||
|
||
/* This is a symlink, in this case read the destination. But let's make sure we don't follow
|
||
* symlinks without bounds. */
|
||
if (--max_follow <= 0)
|
||
return -ELOOP;
|
||
|
||
r = readlinkat_malloc(fd, first + n, &destination);
|
||
if (r < 0)
|
||
return r;
|
||
if (isempty(destination))
|
||
return -EINVAL;
|
||
|
||
if (path_is_absolute(destination)) {
|
||
|
||
/* An absolute destination. Start the loop from the beginning, but use the root
|
||
* directory as base. */
|
||
|
||
safe_close(fd);
|
||
fd = open(root ?: "/", O_CLOEXEC|O_DIRECTORY|O_PATH);
|
||
if (fd < 0)
|
||
return -errno;
|
||
|
||
if (flags & CHASE_SAFE) {
|
||
if (fstat(fd, &st) < 0)
|
||
return -errno;
|
||
|
||
if (unsafe_transition(&previous_stat, &st))
|
||
return log_unsafe_transition(child, fd, path, flags);
|
||
|
||
previous_stat = st;
|
||
}
|
||
|
||
free(done);
|
||
|
||
/* Note that we do not revalidate the root, we take it as is. */
|
||
if (isempty(root))
|
||
done = NULL;
|
||
else {
|
||
done = strdup(root);
|
||
if (!done)
|
||
return -ENOMEM;
|
||
}
|
||
|
||
/* Prefix what's left to do with what we just read, and start the loop again, but
|
||
* remain in the current directory. */
|
||
joined = path_join(destination, todo);
|
||
} else
|
||
joined = path_join("/", destination, todo);
|
||
if (!joined)
|
||
return -ENOMEM;
|
||
|
||
free(buffer);
|
||
todo = buffer = joined;
|
||
|
||
if (flags & CHASE_STEP)
|
||
goto chased_one;
|
||
|
||
continue;
|
||
}
|
||
|
||
/* If this is not a symlink, then let's just add the name we read to what we already verified. */
|
||
if (!done)
|
||
done = TAKE_PTR(first);
|
||
else {
|
||
/* If done is "/", as first also contains slash at the head, then remove this redundant slash. */
|
||
if (streq(done, "/"))
|
||
*done = '\0';
|
||
|
||
if (!strextend(&done, first, NULL))
|
||
return -ENOMEM;
|
||
}
|
||
|
||
/* And iterate again, but go one directory further down. */
|
||
safe_close(fd);
|
||
fd = TAKE_FD(child);
|
||
}
|
||
|
||
if (!done) {
|
||
/* Special case, turn the empty string into "/", to indicate the root directory. */
|
||
done = strdup("/");
|
||
if (!done)
|
||
return -ENOMEM;
|
||
}
|
||
|
||
if (ret_path)
|
||
*ret_path = TAKE_PTR(done);
|
||
|
||
if (ret_fd) {
|
||
/* Return the O_PATH fd we currently are looking to the caller. It can translate it to a
|
||
* proper fd by opening /proc/self/fd/xyz. */
|
||
|
||
assert(fd >= 0);
|
||
*ret_fd = TAKE_FD(fd);
|
||
}
|
||
|
||
if (flags & CHASE_STEP)
|
||
return 1;
|
||
|
||
return exists;
|
||
|
||
chased_one:
|
||
if (ret_path) {
|
||
char *c;
|
||
|
||
c = strjoin(strempty(done), todo);
|
||
if (!c)
|
||
return -ENOMEM;
|
||
|
||
*ret_path = c;
|
||
}
|
||
|
||
return 0;
|
||
}
|
||
|
||
int chase_symlinks_and_open(
|
||
const char *path,
|
||
const char *root,
|
||
unsigned chase_flags,
|
||
int open_flags,
|
||
char **ret_path) {
|
||
|
||
_cleanup_close_ int path_fd = -1;
|
||
_cleanup_free_ char *p = NULL;
|
||
int r;
|
||
|
||
if (chase_flags & CHASE_NONEXISTENT)
|
||
return -EINVAL;
|
||
|
||
if (empty_or_root(root) && !ret_path && (chase_flags & (CHASE_NO_AUTOFS|CHASE_SAFE)) == 0) {
|
||
/* Shortcut this call if none of the special features of this call are requested */
|
||
r = open(path, open_flags);
|
||
if (r < 0)
|
||
return -errno;
|
||
|
||
return r;
|
||
}
|
||
|
||
r = chase_symlinks(path, root, chase_flags, ret_path ? &p : NULL, &path_fd);
|
||
if (r < 0)
|
||
return r;
|
||
assert(path_fd >= 0);
|
||
|
||
r = fd_reopen(path_fd, open_flags);
|
||
if (r < 0)
|
||
return r;
|
||
|
||
if (ret_path)
|
||
*ret_path = TAKE_PTR(p);
|
||
|
||
return r;
|
||
}
|
||
|
||
int chase_symlinks_and_opendir(
|
||
const char *path,
|
||
const char *root,
|
||
unsigned chase_flags,
|
||
char **ret_path,
|
||
DIR **ret_dir) {
|
||
|
||
char procfs_path[STRLEN("/proc/self/fd/") + DECIMAL_STR_MAX(int)];
|
||
_cleanup_close_ int path_fd = -1;
|
||
_cleanup_free_ char *p = NULL;
|
||
DIR *d;
|
||
int r;
|
||
|
||
if (!ret_dir)
|
||
return -EINVAL;
|
||
if (chase_flags & CHASE_NONEXISTENT)
|
||
return -EINVAL;
|
||
|
||
if (empty_or_root(root) && !ret_path && (chase_flags & (CHASE_NO_AUTOFS|CHASE_SAFE)) == 0) {
|
||
/* Shortcut this call if none of the special features of this call are requested */
|
||
d = opendir(path);
|
||
if (!d)
|
||
return -errno;
|
||
|
||
*ret_dir = d;
|
||
return 0;
|
||
}
|
||
|
||
r = chase_symlinks(path, root, chase_flags, ret_path ? &p : NULL, &path_fd);
|
||
if (r < 0)
|
||
return r;
|
||
assert(path_fd >= 0);
|
||
|
||
xsprintf(procfs_path, "/proc/self/fd/%i", path_fd);
|
||
d = opendir(procfs_path);
|
||
if (!d)
|
||
return -errno;
|
||
|
||
if (ret_path)
|
||
*ret_path = TAKE_PTR(p);
|
||
|
||
*ret_dir = d;
|
||
return 0;
|
||
}
|
||
|
||
int chase_symlinks_and_stat(
|
||
const char *path,
|
||
const char *root,
|
||
unsigned chase_flags,
|
||
char **ret_path,
|
||
struct stat *ret_stat,
|
||
int *ret_fd) {
|
||
|
||
_cleanup_close_ int path_fd = -1;
|
||
_cleanup_free_ char *p = NULL;
|
||
int r;
|
||
|
||
assert(path);
|
||
assert(ret_stat);
|
||
|
||
if (chase_flags & CHASE_NONEXISTENT)
|
||
return -EINVAL;
|
||
|
||
if (empty_or_root(root) && !ret_path && (chase_flags & (CHASE_NO_AUTOFS|CHASE_SAFE)) == 0) {
|
||
/* Shortcut this call if none of the special features of this call are requested */
|
||
if (stat(path, ret_stat) < 0)
|
||
return -errno;
|
||
|
||
return 1;
|
||
}
|
||
|
||
r = chase_symlinks(path, root, chase_flags, ret_path ? &p : NULL, &path_fd);
|
||
if (r < 0)
|
||
return r;
|
||
assert(path_fd >= 0);
|
||
|
||
if (fstat(path_fd, ret_stat) < 0)
|
||
return -errno;
|
||
|
||
if (ret_path)
|
||
*ret_path = TAKE_PTR(p);
|
||
if (ret_fd)
|
||
*ret_fd = TAKE_FD(path_fd);
|
||
|
||
return 1;
|
||
}
|
||
|
||
int access_fd(int fd, int mode) {
|
||
char p[STRLEN("/proc/self/fd/") + DECIMAL_STR_MAX(fd) + 1];
|
||
|
||
/* Like access() but operates on an already open fd */
|
||
|
||
xsprintf(p, "/proc/self/fd/%i", fd);
|
||
if (access(p, mode) < 0) {
|
||
if (errno != ENOENT)
|
||
return -errno;
|
||
|
||
/* ENOENT can mean two things: that the fd does not exist or that /proc is not mounted. Let's
|
||
* make things debuggable and distinguish the two. */
|
||
|
||
if (proc_mounted() == 0)
|
||
return -ENOSYS; /* /proc is not available or not set up properly, we're most likely in some chroot
|
||
* environment. */
|
||
|
||
return -EBADF; /* The directory exists, hence it's the fd that doesn't. */
|
||
}
|
||
|
||
return 0;
|
||
}
|
||
|
||
void unlink_tempfilep(char (*p)[]) {
|
||
/* If the file is created with mkstemp(), it will (almost always)
|
||
* change the suffix. Treat this as a sign that the file was
|
||
* successfully created. We ignore both the rare case where the
|
||
* original suffix is used and unlink failures. */
|
||
if (!endswith(*p, ".XXXXXX"))
|
||
(void) unlink_noerrno(*p);
|
||
}
|
||
|
||
int unlinkat_deallocate(int fd, const char *name, UnlinkDeallocateFlags flags) {
|
||
_cleanup_close_ int truncate_fd = -1;
|
||
struct stat st;
|
||
off_t l, bs;
|
||
|
||
assert((flags & ~(UNLINK_REMOVEDIR|UNLINK_ERASE)) == 0);
|
||
|
||
/* Operates like unlinkat() but also deallocates the file contents if it is a regular file and there's no other
|
||
* link to it. This is useful to ensure that other processes that might have the file open for reading won't be
|
||
* able to keep the data pinned on disk forever. This call is particular useful whenever we execute clean-up
|
||
* jobs ("vacuuming"), where we want to make sure the data is really gone and the disk space released and
|
||
* returned to the free pool.
|
||
*
|
||
* Deallocation is preferably done by FALLOC_FL_PUNCH_HOLE|FALLOC_FL_KEEP_SIZE (👊) if supported, which means
|
||
* the file won't change size. That's a good thing since we shouldn't needlessly trigger SIGBUS in other
|
||
* programs that have mmap()ed the file. (The assumption here is that changing file contents to all zeroes
|
||
* underneath those programs is the better choice than simply triggering SIGBUS in them which truncation does.)
|
||
* However if hole punching is not implemented in the kernel or file system we'll fall back to normal file
|
||
* truncation (🔪), as our goal of deallocating the data space trumps our goal of being nice to readers (💐).
|
||
*
|
||
* Note that we attempt deallocation, but failure to succeed with that is not considered fatal, as long as the
|
||
* primary job – to delete the file – is accomplished. */
|
||
|
||
if (!FLAGS_SET(flags, UNLINK_REMOVEDIR)) {
|
||
truncate_fd = openat(fd, name, O_WRONLY|O_CLOEXEC|O_NOCTTY|O_NOFOLLOW|O_NONBLOCK);
|
||
if (truncate_fd < 0) {
|
||
|
||
/* If this failed because the file doesn't exist propagate the error right-away. Also,
|
||
* AT_REMOVEDIR wasn't set, and we tried to open the file for writing, which means EISDIR is
|
||
* returned when this is a directory but we are not supposed to delete those, hence propagate
|
||
* the error right-away too. */
|
||
if (IN_SET(errno, ENOENT, EISDIR))
|
||
return -errno;
|
||
|
||
if (errno != ELOOP) /* don't complain if this is a symlink */
|
||
log_debug_errno(errno, "Failed to open file '%s' for deallocation, ignoring: %m", name);
|
||
}
|
||
}
|
||
|
||
if (unlinkat(fd, name, FLAGS_SET(flags, UNLINK_REMOVEDIR) ? AT_REMOVEDIR : 0) < 0)
|
||
return -errno;
|
||
|
||
if (truncate_fd < 0) /* Don't have a file handle, can't do more ☹️ */
|
||
return 0;
|
||
|
||
if (fstat(truncate_fd, &st) < 0) {
|
||
log_debug_errno(errno, "Failed to stat file '%s' for deallocation, ignoring: %m", name);
|
||
return 0;
|
||
}
|
||
|
||
if (!S_ISREG(st.st_mode))
|
||
return 0;
|
||
|
||
if (FLAGS_SET(flags, UNLINK_ERASE) && st.st_size > 0 && st.st_nlink == 0) {
|
||
uint64_t left = st.st_size;
|
||
char buffer[64 * 1024];
|
||
|
||
/* If erasing is requested, let's overwrite the file with random data once before deleting
|
||
* it. This isn't going to give you shred(1) semantics, but hopefully should be good enough
|
||
* for stuff backed by tmpfs at least.
|
||
*
|
||
* Note that we only erase like this if the link count of the file is zero. If it is higher it
|
||
* is still linked by someone else and we'll leave it to them to remove it securely
|
||
* eventually! */
|
||
|
||
random_bytes(buffer, sizeof(buffer));
|
||
|
||
while (left > 0) {
|
||
ssize_t n;
|
||
|
||
n = write(truncate_fd, buffer, MIN(sizeof(buffer), left));
|
||
if (n < 0) {
|
||
log_debug_errno(errno, "Failed to erase data in file '%s', ignoring.", name);
|
||
break;
|
||
}
|
||
|
||
assert(left >= (size_t) n);
|
||
left -= n;
|
||
}
|
||
|
||
/* Let's refresh metadata */
|
||
if (fstat(truncate_fd, &st) < 0) {
|
||
log_debug_errno(errno, "Failed to stat file '%s' for deallocation, ignoring: %m", name);
|
||
return 0;
|
||
}
|
||
}
|
||
|
||
/* Don't dallocate if there's nothing to deallocate or if the file is linked elsewhere */
|
||
if (st.st_blocks == 0 || st.st_nlink > 0)
|
||
return 0;
|
||
|
||
/* If this is a regular file, it actually took up space on disk and there are no other links it's time to
|
||
* punch-hole/truncate this to release the disk space. */
|
||
|
||
bs = MAX(st.st_blksize, 512);
|
||
l = DIV_ROUND_UP(st.st_size, bs) * bs; /* Round up to next block size */
|
||
|
||
if (fallocate(truncate_fd, FALLOC_FL_PUNCH_HOLE|FALLOC_FL_KEEP_SIZE, 0, l) >= 0)
|
||
return 0; /* Successfully punched a hole! 😊 */
|
||
|
||
/* Fall back to truncation */
|
||
if (ftruncate(truncate_fd, 0) < 0) {
|
||
log_debug_errno(errno, "Failed to truncate file to 0, ignoring: %m");
|
||
return 0;
|
||
}
|
||
|
||
return 0;
|
||
}
|
||
|
||
int fsync_directory_of_file(int fd) {
|
||
_cleanup_free_ char *path = NULL;
|
||
_cleanup_close_ int dfd = -1;
|
||
int r;
|
||
|
||
r = fd_verify_regular(fd);
|
||
if (r < 0)
|
||
return r;
|
||
|
||
r = fd_get_path(fd, &path);
|
||
if (r < 0) {
|
||
log_debug_errno(r, "Failed to query /proc/self/fd/%d%s: %m",
|
||
fd,
|
||
r == -ENOSYS ? ", ignoring" : "");
|
||
|
||
if (r == -ENOSYS)
|
||
/* If /proc is not available, we're most likely running in some
|
||
* chroot environment, and syncing the directory is not very
|
||
* important in that case. Let's just silently do nothing. */
|
||
return 0;
|
||
|
||
return r;
|
||
}
|
||
|
||
if (!path_is_absolute(path))
|
||
return -EINVAL;
|
||
|
||
dfd = open_parent(path, O_CLOEXEC, 0);
|
||
if (dfd < 0)
|
||
return dfd;
|
||
|
||
if (fsync(dfd) < 0)
|
||
return -errno;
|
||
|
||
return 0;
|
||
}
|
||
|
||
int fsync_full(int fd) {
|
||
int r, q;
|
||
|
||
/* Sync both the file and the directory */
|
||
|
||
r = fsync(fd) < 0 ? -errno : 0;
|
||
q = fsync_directory_of_file(fd);
|
||
|
||
return r < 0 ? r : q;
|
||
}
|
||
|
||
int fsync_path_at(int at_fd, const char *path) {
|
||
_cleanup_close_ int opened_fd = -1;
|
||
int fd;
|
||
|
||
if (isempty(path)) {
|
||
if (at_fd == AT_FDCWD) {
|
||
opened_fd = open(".", O_RDONLY|O_DIRECTORY|O_CLOEXEC);
|
||
if (opened_fd < 0)
|
||
return -errno;
|
||
|
||
fd = opened_fd;
|
||
} else
|
||
fd = at_fd;
|
||
} else {
|
||
|
||
opened_fd = openat(at_fd, path, O_RDONLY|O_CLOEXEC);
|
||
if (opened_fd < 0)
|
||
return -errno;
|
||
|
||
fd = opened_fd;
|
||
}
|
||
|
||
if (fsync(fd) < 0)
|
||
return -errno;
|
||
|
||
return 0;
|
||
}
|
||
|
||
int syncfs_path(int atfd, const char *path) {
|
||
_cleanup_close_ int fd = -1;
|
||
|
||
assert(path);
|
||
|
||
fd = openat(atfd, path, O_CLOEXEC|O_RDONLY|O_NONBLOCK);
|
||
if (fd < 0)
|
||
return -errno;
|
||
|
||
if (syncfs(fd) < 0)
|
||
return -errno;
|
||
|
||
return 0;
|
||
}
|
||
|
||
int open_parent(const char *path, int flags, mode_t mode) {
|
||
_cleanup_free_ char *parent = NULL;
|
||
int fd;
|
||
|
||
if (isempty(path))
|
||
return -EINVAL;
|
||
if (path_equal(path, "/")) /* requesting the parent of the root dir is fishy, let's prohibit that */
|
||
return -EINVAL;
|
||
|
||
parent = dirname_malloc(path);
|
||
if (!parent)
|
||
return -ENOMEM;
|
||
|
||
/* Let's insist on O_DIRECTORY since the parent of a file or directory is a directory. Except if we open an
|
||
* O_TMPFILE file, because in that case we are actually create a regular file below the parent directory. */
|
||
|
||
if (FLAGS_SET(flags, O_PATH))
|
||
flags |= O_DIRECTORY;
|
||
else if (!FLAGS_SET(flags, O_TMPFILE))
|
||
flags |= O_DIRECTORY|O_RDONLY;
|
||
|
||
fd = open(parent, flags, mode);
|
||
if (fd < 0)
|
||
return -errno;
|
||
|
||
return fd;
|
||
}
|
||
|
||
static int blockdev_is_encrypted(const char *sysfs_path, unsigned depth_left) {
|
||
_cleanup_free_ char *p = NULL, *uuids = NULL;
|
||
_cleanup_closedir_ DIR *d = NULL;
|
||
int r, found_encrypted = false;
|
||
|
||
assert(sysfs_path);
|
||
|
||
if (depth_left == 0)
|
||
return -EINVAL;
|
||
|
||
p = path_join(sysfs_path, "dm/uuid");
|
||
if (!p)
|
||
return -ENOMEM;
|
||
|
||
r = read_one_line_file(p, &uuids);
|
||
if (r != -ENOENT) {
|
||
if (r < 0)
|
||
return r;
|
||
|
||
/* The DM device's uuid attribute is prefixed with "CRYPT-" if this is a dm-crypt device. */
|
||
if (startswith(uuids, "CRYPT-"))
|
||
return true;
|
||
}
|
||
|
||
/* Not a dm-crypt device itself. But maybe it is on top of one? Follow the links in the "slaves/"
|
||
* subdir. */
|
||
|
||
p = mfree(p);
|
||
p = path_join(sysfs_path, "slaves");
|
||
if (!p)
|
||
return -ENOMEM;
|
||
|
||
d = opendir(p);
|
||
if (!d) {
|
||
if (errno == ENOENT) /* Doesn't have underlying devices */
|
||
return false;
|
||
|
||
return -errno;
|
||
}
|
||
|
||
for (;;) {
|
||
_cleanup_free_ char *q = NULL;
|
||
struct dirent *de;
|
||
|
||
errno = 0;
|
||
de = readdir_no_dot(d);
|
||
if (!de) {
|
||
if (errno != 0)
|
||
return -errno;
|
||
|
||
break; /* No more underlying devices */
|
||
}
|
||
|
||
q = path_join(p, de->d_name);
|
||
if (!q)
|
||
return -ENOMEM;
|
||
|
||
r = blockdev_is_encrypted(q, depth_left - 1);
|
||
if (r < 0)
|
||
return r;
|
||
if (r == 0) /* we found one that is not encrypted? then propagate that immediately */
|
||
return false;
|
||
|
||
found_encrypted = true;
|
||
}
|
||
|
||
return found_encrypted;
|
||
}
|
||
|
||
int path_is_encrypted(const char *path) {
|
||
char p[SYS_BLOCK_PATH_MAX(NULL)];
|
||
dev_t devt;
|
||
int r;
|
||
|
||
r = get_block_device(path, &devt);
|
||
if (r < 0)
|
||
return r;
|
||
if (r == 0) /* doesn't have a block device */
|
||
return false;
|
||
|
||
xsprintf_sys_block_path(p, NULL, devt);
|
||
|
||
return blockdev_is_encrypted(p, 10 /* safety net: maximum recursion depth */);
|
||
}
|