[thirdparty/systemd.git] / src / basic / rm-rf.c

/***
  This file is part of systemd.

  Copyright 2015 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.h>
#include <errno.h>
#include <fcntl.h>
#include <stdbool.h>
#include <stddef.h>
#include <sys/stat.h>
#include <sys/statfs.h>
#include <unistd.h>

#include "btrfs-util.h"
#include "fd-util.h"
#include "log.h"
#include "macro.h"
#include "mount-util.h"
#include "path-util.h"
#include "rm-rf.h"
#include "stat-util.h"
#include "string-util.h"

int rm_rf_children(int fd, RemoveFlags flags, struct stat *root_dev) {
        _cleanup_closedir_ DIR *d = NULL;
        int ret = 0, r;

        assert(fd >= 0);

        /* This returns the first error we run into, but nevertheless
         * tries to go on. This closes the passed fd. */

        if (!(flags & REMOVE_PHYSICAL)) {

                r = fd_is_temporary_fs(fd);
                if (r < 0) {
                        safe_close(fd);
                        return r;
                }

                if (!r) {
                        /* We refuse to clean physical file systems
                         * with this call, unless explicitly
                         * requested. This is extra paranoia just to
                         * be sure we never ever remove non-state
                         * data */

                        log_error("Attempted to remove disk file system, and we can't allow that.");
                        safe_close(fd);
                        return -EPERM;
                }
        }

        d = fdopendir(fd);
        if (!d) {
                safe_close(fd);
                return errno == ENOENT ? 0 : -errno;
        }

        for (;;) {
                struct dirent *de;
                bool is_dir;
                struct stat st;

                errno = 0;
                de = readdir(d);
                if (!de) {
                        if (errno > 0 && ret == 0)
                                ret = -errno;
                        return ret;
                }

                if (streq(de->d_name, ".") || streq(de->d_name, ".."))
                        continue;

                if (de->d_type == DT_UNKNOWN ||
                    (de->d_type == DT_DIR && (root_dev || (flags & REMOVE_SUBVOLUME)))) {
                        if (fstatat(fd, de->d_name, &st, AT_SYMLINK_NOFOLLOW) < 0) {
                                if (ret == 0 && errno != ENOENT)
                                        ret = -errno;
                                continue;
                        }

                        is_dir = S_ISDIR(st.st_mode);
                } else
                        is_dir = de->d_type == DT_DIR;

                if (is_dir) {
                        int subdir_fd;

                        /* if root_dev is set, remove subdirectories only if device is same */
                        if (root_dev && st.st_dev != root_dev->st_dev)
                                continue;

                        subdir_fd = openat(fd, de->d_name, O_RDONLY|O_NONBLOCK|O_DIRECTORY|O_CLOEXEC|O_NOFOLLOW|O_NOATIME);
                        if (subdir_fd < 0) {
                                if (ret == 0 && errno != ENOENT)
                                        ret = -errno;
                                continue;
                        }

                        /* Stop at mount points */
                        r = fd_is_mount_point(fd, de->d_name, 0);
                        if (r < 0) {
                                if (ret == 0 && r != -ENOENT)
                                        ret = r;

                                safe_close(subdir_fd);
                                continue;
                        }
                        if (r) {
                                safe_close(subdir_fd);
                                continue;
                        }

                        if ((flags & REMOVE_SUBVOLUME) && st.st_ino == 256) {

                                /* This could be a subvolume, try to remove it */

                                r = btrfs_subvol_remove_fd(fd, de->d_name, BTRFS_REMOVE_RECURSIVE|BTRFS_REMOVE_QUOTA);
                                if (r < 0) {
                                        if (r != -ENOTTY && r != -EINVAL) {
                                                if (ret == 0)
                                                        ret = r;

                                                safe_close(subdir_fd);
                                                continue;
                                        }

                                        /* ENOTTY, then it wasn't a
                                         * btrfs subvolume, continue
                                         * below. */
                                } else {
                                        /* It was a subvolume, continue. */
                                        safe_close(subdir_fd);
                                        continue;
                                }
                        }

                        /* We pass REMOVE_PHYSICAL here, to avoid
                         * doing the fstatfs() to check the file
                         * system type again for each directory */
                        r = rm_rf_children(subdir_fd, flags | REMOVE_PHYSICAL, root_dev);
                        if (r < 0 && ret == 0)
                                ret = r;

                        if (unlinkat(fd, de->d_name, AT_REMOVEDIR) < 0) {
                                if (ret == 0 && errno != ENOENT)
                                        ret = -errno;
                        }

                } else if (!(flags & REMOVE_ONLY_DIRECTORIES)) {

                        if (unlinkat(fd, de->d_name, 0) < 0) {
                                if (ret == 0 && errno != ENOENT)
                                        ret = -errno;
                        }
                }
        }
}

int rm_rf(const char *path, RemoveFlags flags) {
        int fd, r;
        struct statfs s;

        assert(path);

        /* We refuse to clean the root file system with this
         * call. This is extra paranoia to never cause a really
         * seriously broken system. */
        if (path_equal(path, "/")) {
                log_error("Attempted to remove entire root file system, and we can't allow that.");
                return -EPERM;
        }

        if ((flags & (REMOVE_SUBVOLUME|REMOVE_ROOT|REMOVE_PHYSICAL)) == (REMOVE_SUBVOLUME|REMOVE_ROOT|REMOVE_PHYSICAL)) {
                /* Try to remove as subvolume first */
                r = btrfs_subvol_remove(path, BTRFS_REMOVE_RECURSIVE|BTRFS_REMOVE_QUOTA);
                if (r >= 0)
                        return r;

                if (r != -ENOTTY && r != -EINVAL && r != -ENOTDIR)
                        return r;

                /* Not btrfs or not a subvolume */
        }

        fd = open(path, O_RDONLY|O_NONBLOCK|O_DIRECTORY|O_CLOEXEC|O_NOFOLLOW|O_NOATIME);
        if (fd < 0) {

                if (errno != ENOTDIR && errno != ELOOP)
                        return -errno;

                if (!(flags & REMOVE_PHYSICAL)) {
                        if (statfs(path, &s) < 0)
                                return -errno;

                        if (!is_temporary_fs(&s)) {
                                log_error("Attempted to remove disk file system, and we can't allow that.");
                                return -EPERM;
                        }
                }

                if ((flags & REMOVE_ROOT) && !(flags & REMOVE_ONLY_DIRECTORIES))
                        if (unlink(path) < 0 && errno != ENOENT)
                                return -errno;

                return 0;
        }

        r = rm_rf_children(fd, flags, NULL);

        if (flags & REMOVE_ROOT) {
                if (rmdir(path) < 0) {
                        if (r == 0 && errno != ENOENT)
                                r = -errno;
                }
        }

        return r;
}
Commit	Line	Data
c6878637 LP	1	/***
	2	This file is part of systemd.
	3
	4	Copyright 2015 Lennart Poettering
	5
	6	systemd is free software; you can redistribute it and/or modify it
	7	under the terms of the GNU Lesser General Public License as published by
	8	the Free Software Foundation; either version 2.1 of the License, or
	9	(at your option) any later version.
	10
	11	systemd is distributed in the hope that it will be useful, but
	12	WITHOUT ANY WARRANTY; without even the implied warranty of
	13	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
	14	Lesser General Public License for more details.
	15
	16	You should have received a copy of the GNU Lesser General Public License
	17	along with systemd; If not, see <http://www.gnu.org/licenses/>.
	18	***/
	19
11c3a366 TA	20	#include <dirent.h>
	21	#include <errno.h>
	22	#include <fcntl.h>
	23	#include <stdbool.h>
	24	#include <stddef.h>
	25	#include <sys/stat.h>
	26	#include <sys/statfs.h>
	27	#include <unistd.h>
	28
d9e2daaf	29	#include "btrfs-util.h"
3ffd4af2	30	#include "fd-util.h"
93cc7779 TA	31	#include "log.h"
93cc7779 TA	32	#include "macro.h"
4349cd7c	33	#include "mount-util.h"
07630cea	34	#include "path-util.h"
3ffd4af2	35	#include "rm-rf.h"
8fcde012	36	#include "stat-util.h"
07630cea	37	#include "string-util.h"
c6878637 LP	38
	39	int rm_rf_children(int fd, RemoveFlags flags, struct stat *root_dev) {
	40	_cleanup_closedir_ DIR *d = NULL;
	41	int ret = 0, r;
	42
	43	assert(fd >= 0);
	44
	45	/* This returns the first error we run into, but nevertheless
	46	* tries to go on. This closes the passed fd. */
	47
	48	if (!(flags & REMOVE_PHYSICAL)) {
	49
	50	r = fd_is_temporary_fs(fd);
	51	if (r < 0) {
	52	safe_close(fd);
	53	return r;
	54	}
	55
	56	if (!r) {
	57	/* We refuse to clean physical file systems
	58	* with this call, unless explicitly
	59	* requested. This is extra paranoia just to
	60	* be sure we never ever remove non-state
	61	* data */
	62
	63	log_error("Attempted to remove disk file system, and we can't allow that.");
	64	safe_close(fd);
	65	return -EPERM;
	66	}
	67	}
	68
	69	d = fdopendir(fd);
	70	if (!d) {
	71	safe_close(fd);
	72	return errno == ENOENT ? 0 : -errno;
	73	}
	74
	75	for (;;) {
	76	struct dirent *de;
	77	bool is_dir;
	78	struct stat st;
	79
	80	errno = 0;
	81	de = readdir(d);
	82	if (!de) {
b3267152	83	if (errno > 0 && ret == 0)
c6878637 LP	84	ret = -errno;
	85	return ret;
	86	}
	87
	88	if (streq(de->d_name, ".") \|\| streq(de->d_name, ".."))
	89	continue;
	90
9e9b663a LP	91	if (de->d_type == DT_UNKNOWN \|\|
9e9b663a LP	92	(de->d_type == DT_DIR && (root_dev \|\| (flags & REMOVE_SUBVOLUME)))) {
c6878637 LP	93	if (fstatat(fd, de->d_name, &st, AT_SYMLINK_NOFOLLOW) < 0) {
	94	if (ret == 0 && errno != ENOENT)
	95	ret = -errno;
	96	continue;
	97	}
	98
	99	is_dir = S_ISDIR(st.st_mode);
	100	} else
	101	is_dir = de->d_type == DT_DIR;
	102
	103	if (is_dir) {
	104	int subdir_fd;
	105
f25afeb6	106	/* if root_dev is set, remove subdirectories only if device is same */
c6878637 LP	107	if (root_dev && st.st_dev != root_dev->st_dev)
	108	continue;
	109
	110	subdir_fd = openat(fd, de->d_name, O_RDONLY\|O_NONBLOCK\|O_DIRECTORY\|O_CLOEXEC\|O_NOFOLLOW\|O_NOATIME);
	111	if (subdir_fd < 0) {
	112	if (ret == 0 && errno != ENOENT)
	113	ret = -errno;
	114	continue;
	115	}
	116
f25afeb6	117	/* Stop at mount points */
5d409034	118	r = fd_is_mount_point(fd, de->d_name, 0);
f25afeb6 LP	119	if (r < 0) {
	120	if (ret == 0 && r != -ENOENT)
	121	ret = r;
	122
	123	safe_close(subdir_fd);
	124	continue;
	125	}
	126	if (r) {
	127	safe_close(subdir_fd);
	128	continue;
	129	}
	130
9e9b663a	131	if ((flags & REMOVE_SUBVOLUME) && st.st_ino == 256) {
9e9b663a LP	132
	133	/* This could be a subvolume, try to remove it */
	134
5bcd08db	135	r = btrfs_subvol_remove_fd(fd, de->d_name, BTRFS_REMOVE_RECURSIVE\|BTRFS_REMOVE_QUOTA);
d9e2daaf LP	136	if (r < 0) {
d9e2daaf LP	137	if (r != -ENOTTY && r != -EINVAL) {
9e9b663a	138	if (ret == 0)
d9e2daaf	139	ret = r;
9e9b663a LP	140
	141	safe_close(subdir_fd);
	142	continue;
	143	}
	144
d9e2daaf LP	145	/* ENOTTY, then it wasn't a
	146	* btrfs subvolume, continue
	147	* below. */
9e9b663a LP	148	} else {
	149	/* It was a subvolume, continue. */
	150	safe_close(subdir_fd);
	151	continue;
	152	}
	153	}
	154
c6878637 LP	155	/* We pass REMOVE_PHYSICAL here, to avoid
	156	* doing the fstatfs() to check the file
	157	* system type again for each directory */
	158	r = rm_rf_children(subdir_fd, flags \| REMOVE_PHYSICAL, root_dev);
	159	if (r < 0 && ret == 0)
	160	ret = r;
	161
	162	if (unlinkat(fd, de->d_name, AT_REMOVEDIR) < 0) {
	163	if (ret == 0 && errno != ENOENT)
	164	ret = -errno;
	165	}
	166
	167	} else if (!(flags & REMOVE_ONLY_DIRECTORIES)) {
	168
	169	if (unlinkat(fd, de->d_name, 0) < 0) {
	170	if (ret == 0 && errno != ENOENT)
	171	ret = -errno;
	172	}
	173	}
	174	}
	175	}
	176
	177	int rm_rf(const char *path, RemoveFlags flags) {
	178	int fd, r;
	179	struct statfs s;
	180
	181	assert(path);
	182
	183	/* We refuse to clean the root file system with this
	184	* call. This is extra paranoia to never cause a really
	185	* seriously broken system. */
	186	if (path_equal(path, "/")) {
	187	log_error("Attempted to remove entire root file system, and we can't allow that.");
	188	return -EPERM;
	189	}
	190
d9e2daaf LP	191	if ((flags & (REMOVE_SUBVOLUME\|REMOVE_ROOT\|REMOVE_PHYSICAL)) == (REMOVE_SUBVOLUME\|REMOVE_ROOT\|REMOVE_PHYSICAL)) {
d9e2daaf LP	192	/* Try to remove as subvolume first */
5bcd08db	193	r = btrfs_subvol_remove(path, BTRFS_REMOVE_RECURSIVE\|BTRFS_REMOVE_QUOTA);
d9e2daaf LP	194	if (r >= 0)
	195	return r;
	196
636aabc2	197	if (r != -ENOTTY && r != -EINVAL && r != -ENOTDIR)
d9e2daaf LP	198	return r;
	199
	200	/* Not btrfs or not a subvolume */
	201	}
	202
c6878637 LP	203	fd = open(path, O_RDONLY\|O_NONBLOCK\|O_DIRECTORY\|O_CLOEXEC\|O_NOFOLLOW\|O_NOATIME);
	204	if (fd < 0) {
	205
	206	if (errno != ENOTDIR && errno != ELOOP)
	207	return -errno;
	208
	209	if (!(flags & REMOVE_PHYSICAL)) {
	210	if (statfs(path, &s) < 0)
	211	return -errno;
	212
	213	if (!is_temporary_fs(&s)) {
	214	log_error("Attempted to remove disk file system, and we can't allow that.");
	215	return -EPERM;
	216	}
	217	}
	218
	219	if ((flags & REMOVE_ROOT) && !(flags & REMOVE_ONLY_DIRECTORIES))
	220	if (unlink(path) < 0 && errno != ENOENT)
	221	return -errno;
	222
	223	return 0;
	224	}
	225
	226	r = rm_rf_children(fd, flags, NULL);
	227
	228	if (flags & REMOVE_ROOT) {
d9e2daaf LP	229	if (rmdir(path) < 0) {
d9e2daaf LP	230	if (r == 0 && errno != ENOENT)
c6878637 LP	231	r = -errno;
	232	}
	233	}
	234
	235	return r;
	236	}