mirror of
https://github.com/xen-project/xen.git
synced 2026-10-29 10:40:03 +01:00
Ian Campbell
3e446a35ee
This makes the interface consistent with the changes made to the main interface in 21483:779c0ef9682c. Also fix some references to "struct xc_interface" which should have been simply "xc_interface" in tools/xenpaging, and update QEMU_TAG to pull in the corresponding qemu change. Signed-off-by: Ian Campbell <ian.campbell@citrix.com> Signed-off-by: Ian Jackson <ian.jackson@eu.citrix.com>
135 lines
3.5 KiB
C
135 lines
3.5 KiB
C
/*
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation;
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* version 2.1 of the License.
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*
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with this library; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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*/
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#include "xc_private.h"
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#include "xenguest.h"
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#define SUSPEND_LOCK_FILE "/var/lib/xen/suspend_evtchn"
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static int lock_suspend_event(xc_interface *xch, int domid)
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{
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int fd, rc;
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mode_t mask;
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char buf[128];
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char suspend_file[256];
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snprintf(suspend_file, sizeof(suspend_file), "%s_%d_lock.d",
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SUSPEND_LOCK_FILE, domid);
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mask = umask(022);
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fd = open(suspend_file, O_CREAT | O_EXCL | O_RDWR, 0666);
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if (fd < 0)
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{
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ERROR("Can't create lock file for suspend event channel %s\n",
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suspend_file);
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return -EINVAL;
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}
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umask(mask);
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snprintf(buf, sizeof(buf), "%10ld", (long)getpid());
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rc = write_exact(fd, buf, strlen(buf));
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close(fd);
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return rc;
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}
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static int unlock_suspend_event(xc_interface *xch, int domid)
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{
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int fd, pid, n;
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char buf[128];
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char suspend_file[256];
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snprintf(suspend_file, sizeof(suspend_file), "%s_%d_lock.d",
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SUSPEND_LOCK_FILE, domid);
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fd = open(suspend_file, O_RDWR);
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if (fd < 0)
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return -EINVAL;
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n = read(fd, buf, 127);
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close(fd);
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if (n > 0)
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{
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sscanf(buf, "%d", &pid);
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/* We are the owner, so we can simply delete the file */
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if (pid == getpid())
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{
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unlink(suspend_file);
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return 0;
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}
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}
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return -EPERM;
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}
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int xc_await_suspend(xc_interface *xch, xc_evtchn *xce, int suspend_evtchn)
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{
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int rc;
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do {
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rc = xc_evtchn_pending(xce);
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if (rc < 0) {
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ERROR("error polling suspend notification channel: %d", rc);
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return -1;
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}
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} while (rc != suspend_evtchn);
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/* harmless for one-off suspend */
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if (xc_evtchn_unmask(xce, suspend_evtchn) < 0)
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ERROR("failed to unmask suspend notification channel: %d", rc);
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return 0;
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}
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int xc_suspend_evtchn_release(xc_interface *xch, xc_evtchn *xce, int domid, int suspend_evtchn)
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{
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if (suspend_evtchn >= 0)
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xc_evtchn_unbind(xce, suspend_evtchn);
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return unlock_suspend_event(xch, domid);
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}
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int xc_suspend_evtchn_init(xc_interface *xch, xc_evtchn *xce, int domid, int port)
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{
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int rc, suspend_evtchn = -1;
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if (lock_suspend_event(xch, domid))
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return -EINVAL;
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suspend_evtchn = xc_evtchn_bind_interdomain(xce, domid, port);
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if (suspend_evtchn < 0) {
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ERROR("failed to bind suspend event channel: %d", suspend_evtchn);
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goto cleanup;
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}
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rc = xc_domain_subscribe_for_suspend(xch, domid, port);
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if (rc < 0) {
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ERROR("failed to subscribe to domain: %d", rc);
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goto cleanup;
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}
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/* event channel is pending immediately after binding */
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xc_await_suspend(xch, xce, suspend_evtchn);
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return suspend_evtchn;
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cleanup:
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if (suspend_evtchn != -1)
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xc_suspend_evtchn_release(xch, xce, domid, suspend_evtchn);
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return -1;
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}
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