/*-*- 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; }