diff options
Diffstat (limited to 'src/shared')
| -rw-r--r-- | src/shared/machine-pool.c | 289 | ||||
| -rw-r--r-- | src/shared/machine-pool.h | 26 |
2 files changed, 315 insertions, 0 deletions
diff --git a/src/shared/machine-pool.c b/src/shared/machine-pool.c new file mode 100644 index 0000000000..add19bb5a1 --- /dev/null +++ b/src/shared/machine-pool.c @@ -0,0 +1,289 @@ +/*-*- 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; +} diff --git a/src/shared/machine-pool.h b/src/shared/machine-pool.h new file mode 100644 index 0000000000..5f7bc281eb --- /dev/null +++ b/src/shared/machine-pool.h @@ -0,0 +1,26 @@ +/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/ + +#pragma once + +/*** + 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 "sd-bus.h" + +int setup_machine_directory(sd_bus_error *error); |