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

/* SPDX-License-Identifier: LGPL-2.1+ */

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

#include "alloc-util.h"
#include "btrfs-util.h"
#include "cgroup-util.h"
#include "dirent-util.h"
#include "fd-util.h"
#include "log.h"
#include "macro.h"
#include "mountpoint-util.h"
#include "path-util.h"
#include "rm-rf.h"
#include "stat-util.h"
#include "string-util.h"

static bool is_physical_fs(const struct statfs *sfs) {
        return !is_temporary_fs(sfs) && !is_cgroup_fs(sfs);
}

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

        assert(fd >= 0);

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

        if (!(flags & REMOVE_PHYSICAL)) {

                r = fstatfs(fd, &sfs);
                if (r < 0) {
                        safe_close(fd);
                        return -errno;
                }

                if (is_physical_fs(&sfs)) {
                        /* 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. */
                        _cleanup_free_ char *path = NULL;

                        (void) fd_get_path(fd, &path);
                        log_error("Attempted to remove disk file system under \"%s\", and we can't allow that.",
                                  strna(path));

                        safe_close(fd);
                        return -EPERM;
                }
        }

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

        FOREACH_DIRENT_ALL(de, d, return -errno) {
                bool is_dir;
                struct stat st;

                if (dot_or_dot_dot(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 (!IN_SET(r, -ENOTTY, -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;
                        }
                }
        }
        return ret;
}

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

        assert(path);

        /* For now, don't support dropping subvols when also only dropping directories, since we can't do
         * this race-freely. */
        if (FLAGS_SET(flags, REMOVE_ONLY_DIRECTORIES|REMOVE_SUBVOLUME))
                return -EINVAL;

        /* 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_or_files_same(path, "/", AT_SYMLINK_NOFOLLOW))
                return log_error_errno(SYNTHETIC_ERRNO(EPERM),
                                       "Attempted to remove entire root file system (\"%s\"), and we can't allow that.",
                                       path);

        if (FLAGS_SET(flags, 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 (!IN_SET(r, -ENOTTY, -EINVAL, -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 (!IN_SET(errno, ENOTDIR, ELOOP))
                        return -errno;

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

                        if (is_physical_fs(&s))
                                return log_error_errno(SYNTHETIC_ERRNO(EPERM),
                                                       "Attempted to remove files from a disk file system under \"%s\", refusing.",
                                                       path);
                }

                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
53e1b683	1	/* SPDX-License-Identifier: LGPL-2.1+ */
c6878637	2
11c3a366 TA	3	#include <errno.h>
	4	#include <fcntl.h>
	5	#include <stdbool.h>
	6	#include <stddef.h>
	7	#include <sys/stat.h>
	8	#include <sys/statfs.h>
	9	#include <unistd.h>
	10
265e9be7	11	#include "alloc-util.h"
d9e2daaf	12	#include "btrfs-util.h"
f0bef277	13	#include "cgroup-util.h"
8fb3f009	14	#include "dirent-util.h"
3ffd4af2	15	#include "fd-util.h"
93cc7779 TA	16	#include "log.h"
93cc7779 TA	17	#include "macro.h"
049af8ad	18	#include "mountpoint-util.h"
07630cea	19	#include "path-util.h"
3ffd4af2	20	#include "rm-rf.h"
8fcde012	21	#include "stat-util.h"
07630cea	22	#include "string-util.h"
c6878637	23
f0bef277 EV	24	static bool is_physical_fs(const struct statfs *sfs) {
	25	return !is_temporary_fs(sfs) && !is_cgroup_fs(sfs);
	26	}
	27
c6878637 LP	28	int rm_rf_children(int fd, RemoveFlags flags, struct stat *root_dev) {
c6878637 LP	29	_cleanup_closedir_ DIR *d = NULL;
8fb3f009	30	struct dirent *de;
c6878637	31	int ret = 0, r;
f0bef277	32	struct statfs sfs;
c6878637 LP	33
	34	assert(fd >= 0);
	35
c0ba6b92 LP	36	/* This returns the first error we run into, but nevertheless tries to go on. This closes the passed
c0ba6b92 LP	37	* fd, in all cases, including on failure.. */
c6878637 LP	38
	39	if (!(flags & REMOVE_PHYSICAL)) {
	40
f0bef277	41	r = fstatfs(fd, &sfs);
c6878637 LP	42	if (r < 0) {
c6878637 LP	43	safe_close(fd);
f0bef277	44	return -errno;
c6878637 LP	45	}
c6878637 LP	46
f0bef277	47	if (is_physical_fs(&sfs)) {
265e9be7 ZJS	48	/* We refuse to clean physical file systems with this call,
	49	* unless explicitly requested. This is extra paranoia just
	50	* to be sure we never ever remove non-state data. */
	51	_cleanup_free_ char *path = NULL;
	52
	53	(void) fd_get_path(fd, &path);
	54	log_error("Attempted to remove disk file system under \"%s\", and we can't allow that.",
	55	strna(path));
c6878637	56
c6878637 LP	57	safe_close(fd);
	58	return -EPERM;
	59	}
	60	}
	61
	62	d = fdopendir(fd);
	63	if (!d) {
	64	safe_close(fd);
	65	return errno == ENOENT ? 0 : -errno;
	66	}
	67
8fb3f009	68	FOREACH_DIRENT_ALL(de, d, return -errno) {
c6878637 LP	69	bool is_dir;
	70	struct stat st;
	71
49bfc877	72	if (dot_or_dot_dot(de->d_name))
c6878637 LP	73	continue;
c6878637 LP	74
9e9b663a LP	75	if (de->d_type == DT_UNKNOWN \|\|
9e9b663a LP	76	(de->d_type == DT_DIR && (root_dev \|\| (flags & REMOVE_SUBVOLUME)))) {
c6878637 LP	77	if (fstatat(fd, de->d_name, &st, AT_SYMLINK_NOFOLLOW) < 0) {
	78	if (ret == 0 && errno != ENOENT)
	79	ret = -errno;
	80	continue;
	81	}
	82
	83	is_dir = S_ISDIR(st.st_mode);
	84	} else
	85	is_dir = de->d_type == DT_DIR;
	86
	87	if (is_dir) {
	88	int subdir_fd;
	89
f25afeb6	90	/* if root_dev is set, remove subdirectories only if device is same */
c6878637 LP	91	if (root_dev && st.st_dev != root_dev->st_dev)
	92	continue;
	93
	94	subdir_fd = openat(fd, de->d_name, O_RDONLY\|O_NONBLOCK\|O_DIRECTORY\|O_CLOEXEC\|O_NOFOLLOW\|O_NOATIME);
	95	if (subdir_fd < 0) {
	96	if (ret == 0 && errno != ENOENT)
	97	ret = -errno;
	98	continue;
	99	}
	100
f25afeb6	101	/* Stop at mount points */
5d409034	102	r = fd_is_mount_point(fd, de->d_name, 0);
f25afeb6 LP	103	if (r < 0) {
	104	if (ret == 0 && r != -ENOENT)
	105	ret = r;
	106
	107	safe_close(subdir_fd);
	108	continue;
	109	}
	110	if (r) {
	111	safe_close(subdir_fd);
	112	continue;
	113	}
	114
9e9b663a	115	if ((flags & REMOVE_SUBVOLUME) && st.st_ino == 256) {
9e9b663a LP	116
	117	/* This could be a subvolume, try to remove it */
	118
5bcd08db	119	r = btrfs_subvol_remove_fd(fd, de->d_name, BTRFS_REMOVE_RECURSIVE\|BTRFS_REMOVE_QUOTA);
d9e2daaf	120	if (r < 0) {
4c701096	121	if (!IN_SET(r, -ENOTTY, -EINVAL)) {
9e9b663a	122	if (ret == 0)
d9e2daaf	123	ret = r;
9e9b663a LP	124
	125	safe_close(subdir_fd);
	126	continue;
	127	}
	128
d9e2daaf LP	129	/* ENOTTY, then it wasn't a
	130	* btrfs subvolume, continue
	131	* below. */
9e9b663a LP	132	} else {
	133	/* It was a subvolume, continue. */
	134	safe_close(subdir_fd);
	135	continue;
	136	}
	137	}
	138
c6878637 LP	139	/* We pass REMOVE_PHYSICAL here, to avoid
	140	* doing the fstatfs() to check the file
	141	* system type again for each directory */
	142	r = rm_rf_children(subdir_fd, flags \| REMOVE_PHYSICAL, root_dev);
	143	if (r < 0 && ret == 0)
	144	ret = r;
	145
	146	if (unlinkat(fd, de->d_name, AT_REMOVEDIR) < 0) {
	147	if (ret == 0 && errno != ENOENT)
	148	ret = -errno;
	149	}
	150
	151	} else if (!(flags & REMOVE_ONLY_DIRECTORIES)) {
	152
	153	if (unlinkat(fd, de->d_name, 0) < 0) {
	154	if (ret == 0 && errno != ENOENT)
	155	ret = -errno;
	156	}
	157	}
	158	}
8fb3f009	159	return ret;
c6878637 LP	160	}
	161
	162	int rm_rf(const char *path, RemoveFlags flags) {
	163	int fd, r;
	164	struct statfs s;
	165
	166	assert(path);
	167
c2f64c07 LP	168	/* For now, don't support dropping subvols when also only dropping directories, since we can't do
	169	* this race-freely. */
	170	if (FLAGS_SET(flags, REMOVE_ONLY_DIRECTORIES\|REMOVE_SUBVOLUME))
	171	return -EINVAL;
	172
c6878637 LP	173	/* We refuse to clean the root file system with this
	174	* call. This is extra paranoia to never cause a really
	175	* seriously broken system. */
baaa35ad ZJS	176	if (path_equal_or_files_same(path, "/", AT_SYMLINK_NOFOLLOW))
	177	return log_error_errno(SYNTHETIC_ERRNO(EPERM),
	178	"Attempted to remove entire root file system (\"%s\"), and we can't allow that.",
	179	path);
c6878637	180
d94a24ca	181	if (FLAGS_SET(flags, REMOVE_SUBVOLUME \| REMOVE_ROOT \| REMOVE_PHYSICAL)) {
d9e2daaf	182	/* Try to remove as subvolume first */
5bcd08db	183	r = btrfs_subvol_remove(path, BTRFS_REMOVE_RECURSIVE\|BTRFS_REMOVE_QUOTA);
d9e2daaf LP	184	if (r >= 0)
	185	return r;
	186
4c701096	187	if (!IN_SET(r, -ENOTTY, -EINVAL, -ENOTDIR))
d9e2daaf LP	188	return r;
	189
	190	/* Not btrfs or not a subvolume */
	191	}
	192
c6878637 LP	193	fd = open(path, O_RDONLY\|O_NONBLOCK\|O_DIRECTORY\|O_CLOEXEC\|O_NOFOLLOW\|O_NOATIME);
c6878637 LP	194	if (fd < 0) {
ec2ce0c5	195	if (!IN_SET(errno, ENOTDIR, ELOOP))
c6878637 LP	196	return -errno;
	197
	198	if (!(flags & REMOVE_PHYSICAL)) {
	199	if (statfs(path, &s) < 0)
	200	return -errno;
	201
baaa35ad ZJS	202	if (is_physical_fs(&s))
	203	return log_error_errno(SYNTHETIC_ERRNO(EPERM),
	204	"Attempted to remove files from a disk file system under \"%s\", refusing.",
	205	path);
c6878637 LP	206	}
	207
	208	if ((flags & REMOVE_ROOT) && !(flags & REMOVE_ONLY_DIRECTORIES))
	209	if (unlink(path) < 0 && errno != ENOENT)
	210	return -errno;
	211
	212	return 0;
	213	}
	214
	215	r = rm_rf_children(fd, flags, NULL);
	216
	217	if (flags & REMOVE_ROOT) {
d9e2daaf LP	218	if (rmdir(path) < 0) {
d9e2daaf LP	219	if (r == 0 && errno != ENOENT)
c6878637 LP	220	r = -errno;
	221	}
	222	}
	223
	224	return r;
	225	}