16420be1fd
Be more careful with initialized of the 'relinquished' boolean field, and let's return the fd, like we do for the regular codepath, too.
147 lines
4.1 KiB
C
147 lines
4.1 KiB
C
/* SPDX-License-Identifier: LGPL-2.1+ */
|
|
|
|
#include <errno.h>
|
|
#include <fcntl.h>
|
|
#include <linux/loop.h>
|
|
#include <sys/ioctl.h>
|
|
#include <sys/stat.h>
|
|
|
|
#include "alloc-util.h"
|
|
#include "fd-util.h"
|
|
#include "loop-util.h"
|
|
#include "stat-util.h"
|
|
|
|
int loop_device_make(int fd, int open_flags, LoopDevice **ret) {
|
|
const struct loop_info64 info = {
|
|
.lo_flags = LO_FLAGS_AUTOCLEAR|LO_FLAGS_PARTSCAN|(open_flags == O_RDONLY ? LO_FLAGS_READ_ONLY : 0),
|
|
};
|
|
|
|
_cleanup_close_ int control = -1, loop = -1;
|
|
_cleanup_free_ char *loopdev = NULL;
|
|
struct stat st;
|
|
LoopDevice *d;
|
|
int nr, r;
|
|
|
|
assert(fd >= 0);
|
|
assert(ret);
|
|
assert(IN_SET(open_flags, O_RDWR, O_RDONLY));
|
|
|
|
if (fstat(fd, &st) < 0)
|
|
return -errno;
|
|
|
|
if (S_ISBLK(st.st_mode)) {
|
|
int copy;
|
|
|
|
/* If this is already a block device, store a copy of the fd as it is */
|
|
|
|
copy = fcntl(fd, F_DUPFD_CLOEXEC, 3);
|
|
if (copy < 0)
|
|
return -errno;
|
|
|
|
d = new0(LoopDevice, 1);
|
|
if (!d)
|
|
return -ENOMEM;
|
|
|
|
*d = (LoopDevice) {
|
|
.fd = copy,
|
|
.nr = -1,
|
|
.relinquished = true, /* It's not allocated by us, don't destroy it when this object is freed */
|
|
};
|
|
|
|
*ret = d;
|
|
return d->fd;
|
|
}
|
|
|
|
r = stat_verify_regular(&st);
|
|
if (r < 0)
|
|
return r;
|
|
|
|
control = open("/dev/loop-control", O_RDWR|O_CLOEXEC|O_NOCTTY|O_NONBLOCK);
|
|
if (control < 0)
|
|
return -errno;
|
|
|
|
nr = ioctl(control, LOOP_CTL_GET_FREE);
|
|
if (nr < 0)
|
|
return -errno;
|
|
|
|
if (asprintf(&loopdev, "/dev/loop%i", nr) < 0)
|
|
return -ENOMEM;
|
|
|
|
loop = open(loopdev, O_CLOEXEC|O_NONBLOCK|O_NOCTTY|open_flags);
|
|
if (loop < 0)
|
|
return -errno;
|
|
|
|
if (ioctl(loop, LOOP_SET_FD, fd) < 0)
|
|
return -errno;
|
|
|
|
if (ioctl(loop, LOOP_SET_STATUS64, &info) < 0)
|
|
return -errno;
|
|
|
|
d = new(LoopDevice, 1);
|
|
if (!d)
|
|
return -ENOMEM;
|
|
|
|
*d = (LoopDevice) {
|
|
.fd = TAKE_FD(loop),
|
|
.node = TAKE_PTR(loopdev),
|
|
.nr = nr,
|
|
};
|
|
|
|
*ret = d;
|
|
return d->fd;
|
|
}
|
|
|
|
int loop_device_make_by_path(const char *path, int open_flags, LoopDevice **ret) {
|
|
_cleanup_close_ int fd = -1;
|
|
|
|
assert(path);
|
|
assert(ret);
|
|
assert(IN_SET(open_flags, O_RDWR, O_RDONLY));
|
|
|
|
fd = open(path, O_CLOEXEC|O_NONBLOCK|O_NOCTTY|open_flags);
|
|
if (fd < 0)
|
|
return -errno;
|
|
|
|
return loop_device_make(fd, open_flags, ret);
|
|
}
|
|
|
|
LoopDevice* loop_device_unref(LoopDevice *d) {
|
|
if (!d)
|
|
return NULL;
|
|
|
|
if (d->fd >= 0) {
|
|
|
|
if (d->nr >= 0 && !d->relinquished) {
|
|
if (ioctl(d->fd, LOOP_CLR_FD) < 0)
|
|
log_debug_errno(errno, "Failed to clear loop device: %m");
|
|
|
|
}
|
|
|
|
safe_close(d->fd);
|
|
}
|
|
|
|
if (d->nr >= 0 && !d->relinquished) {
|
|
_cleanup_close_ int control = -1;
|
|
|
|
control = open("/dev/loop-control", O_RDWR|O_CLOEXEC|O_NOCTTY|O_NONBLOCK);
|
|
if (control < 0)
|
|
log_debug_errno(errno, "Failed to open loop control device: %m");
|
|
else {
|
|
if (ioctl(control, LOOP_CTL_REMOVE, d->nr) < 0)
|
|
log_debug_errno(errno, "Failed to remove loop device: %m");
|
|
}
|
|
}
|
|
|
|
free(d->node);
|
|
return mfree(d);
|
|
}
|
|
|
|
void loop_device_relinquish(LoopDevice *d) {
|
|
assert(d);
|
|
|
|
/* Don't attempt to clean up the loop device anymore from this point on. Leave the clean-ing up to the kernel
|
|
* itself, using the loop device "auto-clear" logic we already turned on when creating the device. */
|
|
|
|
d->relinquished = true;
|
|
}
|