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Systemd/src/shared/machine-pool.c
Lennart Poettering 8e766630f0 tree-wide: drop redundant _cleanup_ macros (#8810) 
This drops a good number of type-specific _cleanup_ macros, and patches
all users to just use the generic ones.

In most recent code we abstained from defining type-specific macros, and
this basically removes all those added already, with the exception of
the really low-level ones.

Having explicit macros for this is not too useful, as the expression
without the extra macro is generally just 2ch wider. We should generally
emphesize generic code, unless there are really good reasons for
specific code, hence let's follow this in this case too.

Note that _cleanup_free_ and similar really low-level, libc'ish, Linux
API'ish macros continue to be defined, only the really high-level OO
ones are dropped. From now on this should really be the rule: for really
low-level stuff, such as memory allocation, fd handling and so one, go
ahead and define explicit per-type macros, but for high-level, specific
program code, just use the generic _cleanup_() macro directly, in order
to keep things simple and as readable as possible for the uninitiated.

Note that before this patch some of the APIs (notable libudev ones) were
already used with the high-level macros at some places and with the
generic _cleanup_ macro at others. With this patch we hence unify on the
latter.
2018-04-25 12:31:45 +02:00

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/* SPDX-License-Identifier: LGPL-2.1+ */
/***
This file is part of systemd.
Copyright 2015 Lennart Poettering
***/
#include <errno.h>
#include <fcntl.h>
#include <linux/loop.h>
#include <signal.h>
#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include <sys/file.h>
#include <sys/ioctl.h>
#include <sys/mount.h>
#include <sys/prctl.h>
#include <sys/stat.h>
#include <sys/statfs.h>
#include <sys/statvfs.h>
#include <unistd.h>
#include "sd-bus-protocol.h"
#include "sd-bus.h"
#include "alloc-util.h"
#include "btrfs-util.h"
#include "fd-util.h"
#include "fileio.h"
#include "fs-util.h"
#include "label.h"
#include "lockfile-util.h"
#include "log.h"
#include "machine-pool.h"
#include "macro.h"
#include "missing.h"
#include "mkdir.h"
#include "mount-util.h"
#include "parse-util.h"
#include "path-util.h"
#include "process-util.h"
#include "signal-util.h"
#include "stat-util.h"
#include "string-util.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(uint64_t size, sd_bus_error *error) {
_cleanup_free_ char *tmp = NULL;
_cleanup_close_ int fd = -1;
struct statvfs ss;
pid_t pid = 0;
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)
return TAKE_FD(fd);
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", NULL, &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, size) < 0) {
r = sd_bus_error_set_errnof(error, errno, "Failed to enlarge /var/lib/machines.raw: %m");
goto fail;
}
r = safe_fork("(mkfs)", FORK_RESET_SIGNALS|FORK_DEATHSIG, &pid);
if (r < 0) {
sd_bus_error_set_errnof(error, r, "Failed to fork mkfs.btrfs: %m");
goto fail;
}
if (r == 0) {
/* Child */
fd = safe_close(fd);
execlp("mkfs.btrfs", "-Lvar-lib-machines", tmp, NULL);
if (errno == ENOENT)
_exit(99);
_exit(EXIT_FAILURE);
}
r = wait_for_terminate_and_check("mkfs", pid, 0);
pid = 0;
if (r < 0) {
sd_bus_error_set_errnof(error, r, "Failed to wait for mkfs.btrfs: %m");
goto fail;
}
if (r == 99) {
r = sd_bus_error_set_errnof(error, ENOENT, "Cannot set up /var/lib/machines, mkfs.btrfs is missing");
goto fail;
}
if (r != EXIT_SUCCESS) {
r = sd_bus_error_setf(error, SD_BUS_ERROR_FAILED, "mkfs.btrfs failed with error code %i", r);
goto fail;
}
r = rename_noreplace(AT_FDCWD, tmp, AT_FDCWD, "/var/lib/machines.raw");
if (r < 0) {
sd_bus_error_set_errnof(error, r, "Failed to move /var/lib/machines.raw into place: %m");
goto fail;
}
return TAKE_FD(fd);
fail:
unlink_noerrno(tmp);
if (pid > 1)
kill_and_sigcont(pid, SIGKILL);
return r;
}
int setup_machine_directory(uint64_t size, sd_bus_error *error) {
_cleanup_(release_lock_file) LockFile lock_file = LOCK_FILE_INIT;
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/machine-pool.XXXXXX", *mntdir = NULL;
bool tmpdir_made = false, mntdir_made = false, mntdir_mounted = false;
char buf[FORMAT_BYTES_MAX];
int r, nr = -1;
/* btrfs cannot handle file systems < 16M, hence use this as minimum */
if (size == (uint64_t) -1)
size = VAR_LIB_MACHINES_SIZE_START;
else if (size < 16*1024*1024)
size = 16*1024*1024;
/* Make sure we only set the directory up once at a time */
r = make_lock_file("/run/systemd/machines.lock", LOCK_EX, &lock_file);
if (r < 0)
return r;
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 for /var/lib/machines, ignoring: %m");
r = btrfs_subvol_auto_qgroup("/var/lib/machines", 0, true);
if (r < 0)
log_warning_errno(r, "Failed to set up default quota hierarchy for /var/lib/machines, ignoring: %m");
return 1;
}
if (path_is_mount_point("/var/lib/machines", NULL, AT_SYMLINK_FOLLOW) > 0) {
log_debug("/var/lib/machines is already a mount point, not creating loopback file for it.");
return 0;
}
r = dir_is_populated("/var/lib/machines");
if (r < 0 && r != -ENOENT)
return r;
if (r > 0) {
log_debug("/var/log/machines is already populated, not creating loopback file for it.");
return 0;
}
r = mkfs_exists("btrfs");
if (r == 0)
return sd_bus_error_set_errnof(error, ENOENT, "Cannot set up /var/lib/machines, mkfs.btrfs is missing");
if (r < 0)
return r;
fd = setup_machine_raw(size, 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");
r = btrfs_subvol_auto_qgroup(mntdir, 0, true);
if (r < 0)
log_warning_errno(r, "Failed to set up default quota hierarchy, 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) syncfs(fd);
log_info("Set up /var/lib/machines as btrfs loopback file system of size %s mounted on /var/lib/machines.raw.", format_bytes(buf, sizeof(buf), size));
(void) umount2(mntdir, MNT_DETACH);
(void) rmdir(mntdir);
(void) rmdir(tmpdir);
return 1;
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;
}
static int sync_path(const char *p) {
_cleanup_close_ int fd = -1;
fd = open(p, O_RDONLY|O_CLOEXEC|O_NOCTTY);
if (fd < 0)
return -errno;
if (syncfs(fd) < 0)
return -errno;
return 0;
}
int grow_machine_directory(void) {
char buf[FORMAT_BYTES_MAX];
struct statvfs a, b;
uint64_t old_size, new_size, max_add;
int r;
/* Ensure the disk space data is accurate */
sync_path("/var/lib/machines");
sync_path("/var/lib/machines.raw");
if (statvfs("/var/lib/machines.raw", &a) < 0)
return -errno;
if (statvfs("/var/lib/machines", &b) < 0)
return -errno;
/* Don't grow if not enough disk space is available on the host */
if (((uint64_t) a.f_bavail * (uint64_t) a.f_bsize) <= VAR_LIB_MACHINES_FREE_MIN)
return 0;
/* Don't grow if at least 1/3th of the fs is still free */
if (b.f_bavail > b.f_blocks / 3)
return 0;
/* Calculate how much we are willing to add at most */
max_add = ((uint64_t) a.f_bavail * (uint64_t) a.f_bsize) - VAR_LIB_MACHINES_FREE_MIN;
/* Calculate the old size */
old_size = (uint64_t) b.f_blocks * (uint64_t) b.f_bsize;
/* Calculate the new size as three times the size of what is used right now */
new_size = ((uint64_t) b.f_blocks - (uint64_t) b.f_bavail) * (uint64_t) b.f_bsize * 3;
/* Always, grow at least to the start size */
if (new_size < VAR_LIB_MACHINES_SIZE_START)
new_size = VAR_LIB_MACHINES_SIZE_START;
/* If the new size is smaller than the old size, don't grow */
if (new_size < old_size)
return 0;
/* Ensure we never add more than the maximum */
if (new_size > old_size + max_add)
new_size = old_size + max_add;
r = btrfs_resize_loopback("/var/lib/machines", new_size, true);
if (r <= 0)
return r;
/* Also bump the quota, of both the subvolume leaf qgroup, as
* well as of any subtree quota group by the same id but a
* higher level, if it exists. */
(void) btrfs_qgroup_set_limit("/var/lib/machines", 0, new_size);
(void) btrfs_subvol_set_subtree_quota_limit("/var/lib/machines", 0, new_size);
log_info("Grew /var/lib/machines btrfs loopback file system to %s.", format_bytes(buf, sizeof(buf), new_size));
return 1;
}
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