[thirdparty/systemd.git] / src / shared / machine-pool.c

/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/

/***
  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 <sys/prctl.h>
#include <sys/vfs.h>
#include <sys/statvfs.h>
#include <sys/mount.h>

#include "util.h"
#include "mkdir.h"
#include "btrfs-util.h"
#include "path-util.h"
#include "machine-pool.h"

#define VAR_LIB_MACHINES_SIZE_START (1024UL*1024UL*500UL)
#define VAR_LIB_MACHINES_FREE_MIN (1024UL*1024UL*750UL)

static int check_btrfs(void) {
        struct statfs sfs;

        if (statfs("/var/lib/machines", &sfs) < 0) {
                if (errno != ENOENT)
                        return -errno;

                if (statfs("/var/lib", &sfs) < 0)
                        return -errno;
        }

        return F_TYPE_EQUAL(sfs.f_type, BTRFS_SUPER_MAGIC);
}

static int setup_machine_raw(sd_bus_error *error) {
        _cleanup_free_ char *tmp = NULL;
        _cleanup_close_ int fd = -1;
        struct statvfs ss;
        pid_t pid = 0;
        siginfo_t si;
        int r;

        /* We want to be able to make use of btrfs-specific file
         * system features, in particular subvolumes, reflinks and
         * quota. Hence, if we detect that /var/lib/machines.raw is
         * not located on btrfs, let's create a loopback file, place a
         * btrfs file system into it, and mount it to
         * /var/lib/machines. */

        fd = open("/var/lib/machines.raw", O_RDWR|O_CLOEXEC|O_NONBLOCK|O_NOCTTY);
        if (fd >= 0) {
                r = fd;
                fd = -1;
                return r;
        }

        if (errno != ENOENT)
                return sd_bus_error_set_errnof(error, errno, "Failed to open /var/lib/machines.raw: %m");

        r = tempfn_xxxxxx("/var/lib/machines.raw", &tmp);
        if (r < 0)
                return r;

        (void) mkdir_p_label("/var/lib", 0755);
        fd = open(tmp, O_RDWR|O_CREAT|O_EXCL|O_NOCTTY|O_CLOEXEC, 0600);
        if (fd < 0)
                return sd_bus_error_set_errnof(error, errno, "Failed to create /var/lib/machines.raw: %m");

        if (fstatvfs(fd, &ss) < 0) {
                r = sd_bus_error_set_errnof(error, errno, "Failed to determine free space on /var/lib/machines.raw: %m");
                goto fail;
        }

        if (ss.f_bsize * ss.f_bavail < VAR_LIB_MACHINES_FREE_MIN) {
                r = sd_bus_error_setf(error, SD_BUS_ERROR_FAILED, "Not enough free disk space to set up /var/lib/machines.");
                goto fail;
        }

        if (ftruncate(fd, VAR_LIB_MACHINES_SIZE_START) < 0) {
                r = sd_bus_error_set_errnof(error, errno, "Failed to enlarge /var/lib/machines.raw: %m");
                goto fail;
        }

        pid = fork();
        if (pid < 0) {
                r = sd_bus_error_set_errnof(error, errno, "Failed to fork mkfs.btrfs: %m");
                goto fail;
        }

        if (pid == 0) {

                /* Child */

                reset_all_signal_handlers();
                reset_signal_mask();
                assert_se(prctl(PR_SET_PDEATHSIG, SIGTERM) == 0);

                fd = safe_close(fd);

                execlp("mkfs.btrfs", "-Lvar-lib-machines", tmp, NULL);
                if (errno == ENOENT)
                        return 99;

                _exit(EXIT_FAILURE);
        }

        r = wait_for_terminate(pid, &si);
        if (r < 0) {
                sd_bus_error_set_errnof(error, r, "Failed to wait for mkfs.btrfs: %m");
                goto fail;
        }

        pid = 0;

        if (si.si_code != CLD_EXITED) {
                r = sd_bus_error_setf(error, SD_BUS_ERROR_FAILED, "mkfs.btrfs died abnormally.");
                goto fail;
        }
        if (si.si_status == 99) {
                r = sd_bus_error_set_errnof(error, ENOENT, "Cannot set up /var/lib/machines, mkfs.btrfs is missing");
                goto fail;
        }
        if (si.si_status != 0) {
                r = sd_bus_error_setf(error, SD_BUS_ERROR_FAILED, "mkfs.btrfs failed with error code %i", si.si_status);
                goto fail;
        }

        if (renameat2(AT_FDCWD, tmp, AT_FDCWD, "/var/lib/machines.raw", RENAME_NOREPLACE) < 0) {
                r = sd_bus_error_set_errnof(error, errno, "Failed to move /var/lib/machines.raw into place: %m");
                goto fail;
        }

        r = fd;
        fd = -1;

        return r;

fail:
        if (tmp)
                unlink_noerrno(tmp);

        if (pid > 1)
                kill_and_sigcont(pid, SIGKILL);

        return r;
}

int setup_machine_directory(sd_bus_error *error) {
        struct loop_info64 info = {
                .lo_flags = LO_FLAGS_AUTOCLEAR,
        };
        _cleanup_close_ int fd = -1, control = -1, loop = -1;
        _cleanup_free_ char* loopdev = NULL;
        char tmpdir[] = "/tmp/import-mount.XXXXXX", *mntdir = NULL;
        bool tmpdir_made = false, mntdir_made = false, mntdir_mounted = false;
        int r, nr = -1;

        r = check_btrfs();
        if (r < 0)
                return sd_bus_error_set_errnof(error, r, "Failed to determine whether /var/lib/machines is located on btrfs: %m");
        if (r > 0) {
                (void) btrfs_subvol_make_label("/var/lib/machines");

                r = btrfs_quota_enable("/var/lib/machines", true);
                if (r < 0)
                        log_warning_errno(r, "Failed to enable quota, ignoring: %m");

                return 0;
        }

        if (path_is_mount_point("/var/lib/machines", true) > 0 ||
            dir_is_empty("/var/lib/machines") == 0)
                return sd_bus_error_setf(error, SD_BUS_ERROR_INVALID_ARGS, "/var/lib/machines is not a btrfs file system. Operation is not supported on legacy file systems.");

        fd = setup_machine_raw(error);
        if (fd < 0)
                return fd;

        control = open("/dev/loop-control", O_RDWR|O_CLOEXEC|O_NOCTTY|O_NONBLOCK);
        if (control < 0)
                return sd_bus_error_set_errnof(error, errno, "Failed to open /dev/loop-control: %m");

        nr = ioctl(control, LOOP_CTL_GET_FREE);
        if (nr < 0)
                return sd_bus_error_set_errnof(error, errno, "Failed to allocate loop device: %m");

        if (asprintf(&loopdev, "/dev/loop%i", nr) < 0) {
                r = -ENOMEM;
                goto fail;
        }

        loop = open(loopdev, O_CLOEXEC|O_RDWR|O_NOCTTY|O_NONBLOCK);
        if (loop < 0) {
                r = sd_bus_error_set_errnof(error, errno, "Failed to open loopback device: %m");
                goto fail;
        }

        if (ioctl(loop, LOOP_SET_FD, fd) < 0) {
                r = sd_bus_error_set_errnof(error, errno, "Failed to bind loopback device: %m");
                goto fail;
        }

        if (ioctl(loop, LOOP_SET_STATUS64, &info) < 0) {
                r = sd_bus_error_set_errnof(error, errno, "Failed to enable auto-clear for loopback device: %m");
                goto fail;
        }

        /* We need to make sure the new /var/lib/machines directory
         * has an access mode of 0700 at the time it is first made
         * available. mkfs will create it with 0755 however. Hence,
         * let's mount the directory into an inaccessible directory
         * below /tmp first, fix the access mode, and move it to the
         * public place then. */

        if (!mkdtemp(tmpdir)) {
                r = sd_bus_error_set_errnof(error, errno, "Failed to create temporary mount parent directory: %m");
                goto fail;
        }
        tmpdir_made = true;

        mntdir = strjoina(tmpdir, "/mnt");
        if (mkdir(mntdir, 0700) < 0) {
                r = sd_bus_error_set_errnof(error, errno, "Failed to create temporary mount directory: %m");
                goto fail;
        }
        mntdir_made = true;

        if (mount(loopdev, mntdir, "btrfs", 0, NULL) < 0) {
                r = sd_bus_error_set_errnof(error, errno, "Failed to mount loopback device: %m");
                goto fail;
        }
        mntdir_mounted = true;

        r = btrfs_quota_enable(mntdir, true);
        if (r < 0)
                log_warning_errno(r, "Failed to enable quota, ignoring: %m");

        if (chmod(mntdir, 0700) < 0) {
                r = sd_bus_error_set_errnof(error, errno, "Failed to fix owner: %m");
                goto fail;
        }

        (void) mkdir_p_label("/var/lib/machines", 0700);

        if (mount(mntdir, "/var/lib/machines", NULL, MS_BIND, NULL) < 0) {
                r = sd_bus_error_set_errnof(error, errno, "Failed to mount directory into right place: %m");
                goto fail;
        }

        (void) umount2(mntdir, MNT_DETACH);
        (void) rmdir(mntdir);
        (void) rmdir(tmpdir);

        return 0;

fail:
        if (mntdir_mounted)
                (void) umount2(mntdir, MNT_DETACH);

        if (mntdir_made)
                (void) rmdir(mntdir);
        if (tmpdir_made)
                (void) rmdir(tmpdir);

        if (loop >= 0) {
                (void) ioctl(loop, LOOP_CLR_FD);
                loop = safe_close(loop);
        }

        if (control >= 0 && nr >= 0)
                (void) ioctl(control, LOOP_CTL_REMOVE, nr);

        return r;
}
Commit	Line	Data
432cea00 LP	1	/-- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil --/
	2
	3	/***
	4	This file is part of systemd.
	5
	6	Copyright 2015 Lennart Poettering
	7
	8	systemd is free software; you can redistribute it and/or modify it
	9	under the terms of the GNU Lesser General Public License as published by
	10	the Free Software Foundation; either version 2.1 of the License, or
	11	(at your option) any later version.
	12
	13	systemd is distributed in the hope that it will be useful, but
	14	WITHOUT ANY WARRANTY; without even the implied warranty of
	15	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
	16	Lesser General Public License for more details.
	17
	18	You should have received a copy of the GNU Lesser General Public License
	19	along with systemd; If not, see <http://www.gnu.org/licenses/>.
	20	***/
	21
	22	#include <sys/prctl.h>
	23	#include <sys/vfs.h>
	24	#include <sys/statvfs.h>
	25	#include <sys/mount.h>
	26
	27	#include "util.h"
	28	#include "mkdir.h"
	29	#include "btrfs-util.h"
	30	#include "path-util.h"
	31	#include "machine-pool.h"
	32
	33	#define VAR_LIB_MACHINES_SIZE_START (1024UL1024UL500UL)
	34	#define VAR_LIB_MACHINES_FREE_MIN (1024UL1024UL750UL)
	35
	36	static int check_btrfs(void) {
	37	struct statfs sfs;
	38
	39	if (statfs("/var/lib/machines", &sfs) < 0) {
	40	if (errno != ENOENT)
	41	return -errno;
	42
	43	if (statfs("/var/lib", &sfs) < 0)
	44	return -errno;
	45	}
	46
	47	return F_TYPE_EQUAL(sfs.f_type, BTRFS_SUPER_MAGIC);
	48	}
	49
	50	static int setup_machine_raw(sd_bus_error *error) {
	51	_cleanup_free_ char *tmp = NULL;
	52	_cleanup_close_ int fd = -1;
	53	struct statvfs ss;
	54	pid_t pid = 0;
	55	siginfo_t si;
	56	int r;
	57
	58	/* We want to be able to make use of btrfs-specific file
	59	* system features, in particular subvolumes, reflinks and
	60	* quota. Hence, if we detect that /var/lib/machines.raw is
	61	* not located on btrfs, let's create a loopback file, place a
	62	* btrfs file system into it, and mount it to
	63	* /var/lib/machines. */
	64
65	fd = open("/var/lib/machines.raw", O_RDWR\|O_CLOEXEC\|O_NONBLOCK\|O_NOCTTY);
66	if (fd >= 0) {
67	r = fd;
68	fd = -1;
69	return r;
70	}
71
72	if (errno != ENOENT)
73	return sd_bus_error_set_errnof(error, errno, "Failed to open /var/lib/machines.raw: %m");
74
75	r = tempfn_xxxxxx("/var/lib/machines.raw", &tmp);
76	if (r < 0)
77	return r;
78
79	(void) mkdir_p_label("/var/lib", 0755);
80	fd = open(tmp, O_RDWR\|O_CREAT\|O_EXCL\|O_NOCTTY\|O_CLOEXEC, 0600);
81	if (fd < 0)
82	return sd_bus_error_set_errnof(error, errno, "Failed to create /var/lib/machines.raw: %m");
83
84	if (fstatvfs(fd, &ss) < 0) {
85	r = sd_bus_error_set_errnof(error, errno, "Failed to determine free space on /var/lib/machines.raw: %m");
86	goto fail;
87	}
88
89	if (ss.f_bsize * ss.f_bavail < VAR_LIB_MACHINES_FREE_MIN) {
90	r = sd_bus_error_setf(error, SD_BUS_ERROR_FAILED, "Not enough free disk space to set up /var/lib/machines.");
91	goto fail;
92	}
93
94	if (ftruncate(fd, VAR_LIB_MACHINES_SIZE_START) < 0) {
95	r = sd_bus_error_set_errnof(error, errno, "Failed to enlarge /var/lib/machines.raw: %m");
96	goto fail;
97	}
98
99	pid = fork();
100	if (pid < 0) {
101	r = sd_bus_error_set_errnof(error, errno, "Failed to fork mkfs.btrfs: %m");
102	goto fail;
103	}
104
105	if (pid == 0) {
106
107	/* Child */
108
109	reset_all_signal_handlers();
110	reset_signal_mask();
111	assert_se(prctl(PR_SET_PDEATHSIG, SIGTERM) == 0);
112
113	fd = safe_close(fd);
114
115	execlp("mkfs.btrfs", "-Lvar-lib-machines", tmp, NULL);
116	if (errno == ENOENT)
117	return 99;
118
119	_exit(EXIT_FAILURE);
120	}
121
122	r = wait_for_terminate(pid, &si);
123	if (r < 0) {
124	sd_bus_error_set_errnof(error, r, "Failed to wait for mkfs.btrfs: %m");
125	goto fail;
126	}
127
128	pid = 0;
129
130	if (si.si_code != CLD_EXITED) {
131	r = sd_bus_error_setf(error, SD_BUS_ERROR_FAILED, "mkfs.btrfs died abnormally.");
132	goto fail;
133	}
134	if (si.si_status == 99) {
135	r = sd_bus_error_set_errnof(error, ENOENT, "Cannot set up /var/lib/machines, mkfs.btrfs is missing");
136	goto fail;
137	}
138	if (si.si_status != 0) {
139	r = sd_bus_error_setf(error, SD_BUS_ERROR_FAILED, "mkfs.btrfs failed with error code %i", si.si_status);
140	goto fail;
141	}
142
143	if (renameat2(AT_FDCWD, tmp, AT_FDCWD, "/var/lib/machines.raw", RENAME_NOREPLACE) < 0) {
144	r = sd_bus_error_set_errnof(error, errno, "Failed to move /var/lib/machines.raw into place: %m");
145	goto fail;
146	}
147
148	r = fd;
149	fd = -1;
150
151	return r;
152
153	fail:
154	if (tmp)
155	unlink_noerrno(tmp);
156
157	if (pid > 1)
158	kill_and_sigcont(pid, SIGKILL);
159
160	return r;
161	}
162
163	int setup_machine_directory(sd_bus_error *error) {
164	struct loop_info64 info = {
165	.lo_flags = LO_FLAGS_AUTOCLEAR,
166	};
167	_cleanup_close_ int fd = -1, control = -1, loop = -1;
168	_cleanup_free_ char* loopdev = NULL;
169	char tmpdir[] = "/tmp/import-mount.XXXXXX", *mntdir = NULL;
170	bool tmpdir_made = false, mntdir_made = false, mntdir_mounted = false;
171	int r, nr = -1;
172
173	r = check_btrfs();
174	if (r < 0)
175	return sd_bus_error_set_errnof(error, r, "Failed to determine whether /var/lib/machines is located on btrfs: %m");
176	if (r > 0) {
177	(void) btrfs_subvol_make_label("/var/lib/machines");
178
179	r = btrfs_quota_enable("/var/lib/machines", true);
180	if (r < 0)
181	log_warning_errno(r, "Failed to enable quota, ignoring: %m");
182
183	return 0;
184	}
185
186	if (path_is_mount_point("/var/lib/machines", true) > 0 \|\|
187	dir_is_empty("/var/lib/machines") == 0)
188	return sd_bus_error_setf(error, SD_BUS_ERROR_INVALID_ARGS, "/var/lib/machines is not a btrfs file system. Operation is not supported on legacy file systems.");
189
190	fd = setup_machine_raw(error);
191	if (fd < 0)
192	return fd;
193
194	control = open("/dev/loop-control", O_RDWR\|O_CLOEXEC\|O_NOCTTY\|O_NONBLOCK);
195	if (control < 0)
196	return sd_bus_error_set_errnof(error, errno, "Failed to open /dev/loop-control: %m");
197
198	nr = ioctl(control, LOOP_CTL_GET_FREE);
199	if (nr < 0)
200	return sd_bus_error_set_errnof(error, errno, "Failed to allocate loop device: %m");
201
202	if (asprintf(&loopdev, "/dev/loop%i", nr) < 0) {
203	r = -ENOMEM;
204	goto fail;
205	}
206
207	loop = open(loopdev, O_CLOEXEC\|O_RDWR\|O_NOCTTY\|O_NONBLOCK);
208	if (loop < 0) {
209	r = sd_bus_error_set_errnof(error, errno, "Failed to open loopback device: %m");
210	goto fail;
211	}
212
213	if (ioctl(loop, LOOP_SET_FD, fd) < 0) {
214	r = sd_bus_error_set_errnof(error, errno, "Failed to bind loopback device: %m");
215	goto fail;
216	}
217
218	if (ioctl(loop, LOOP_SET_STATUS64, &info) < 0) {
219	r = sd_bus_error_set_errnof(error, errno, "Failed to enable auto-clear for loopback device: %m");
220	goto fail;
221	}
222
223	/* We need to make sure the new /var/lib/machines directory
224	* has an access mode of 0700 at the time it is first made
225	* available. mkfs will create it with 0755 however. Hence,
226	* let's mount the directory into an inaccessible directory
227	* below /tmp first, fix the access mode, and move it to the
228	* public place then. */
229
230	if (!mkdtemp(tmpdir)) {
231	r = sd_bus_error_set_errnof(error, errno, "Failed to create temporary mount parent directory: %m");
232	goto fail;
233	}
234	tmpdir_made = true;
235
236	mntdir = strjoina(tmpdir, "/mnt");
237	if (mkdir(mntdir, 0700) < 0) {
238	r = sd_bus_error_set_errnof(error, errno, "Failed to create temporary mount directory: %m");
239	goto fail;
240	}
241	mntdir_made = true;
242
243	if (mount(loopdev, mntdir, "btrfs", 0, NULL) < 0) {
244	r = sd_bus_error_set_errnof(error, errno, "Failed to mount loopback device: %m");
245	goto fail;
246	}
247	mntdir_mounted = true;
248
249	r = btrfs_quota_enable(mntdir, true);
250	if (r < 0)
251	log_warning_errno(r, "Failed to enable quota, ignoring: %m");
252
253	if (chmod(mntdir, 0700) < 0) {
254	r = sd_bus_error_set_errnof(error, errno, "Failed to fix owner: %m");
255	goto fail;
256	}
257
258	(void) mkdir_p_label("/var/lib/machines", 0700);
259
260	if (mount(mntdir, "/var/lib/machines", NULL, MS_BIND, NULL) < 0) {
261	r = sd_bus_error_set_errnof(error, errno, "Failed to mount directory into right place: %m");
262	goto fail;
263	}
264
265	(void) umount2(mntdir, MNT_DETACH);
266	(void) rmdir(mntdir);
267	(void) rmdir(tmpdir);
268
269	return 0;
270
271	fail:
272	if (mntdir_mounted)
273	(void) umount2(mntdir, MNT_DETACH);
274
275	if (mntdir_made)
276	(void) rmdir(mntdir);
277	if (tmpdir_made)
278	(void) rmdir(tmpdir);
279
280	if (loop >= 0) {
281	(void) ioctl(loop, LOOP_CLR_FD);
282	loop = safe_close(loop);
283	}
284
285	if (control >= 0 && nr >= 0)
286	(void) ioctl(control, LOOP_CTL_REMOVE, nr);
287
288	return r;
289	}