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https://github.com/xen-project/xen.git
synced 2026-10-28 18:21:39 +01:00
Juergen Gross
29a6082f21
Today the file descriptor for the access of the event channel driver is being closed in case of exec(2). For the support of live update of a daemon using libxenevtchn this can be problematic, so add a way to keep that file descriptor open. Add support of a flag XENEVTCHN_NO_CLOEXEC for xenevtchn_open() which will result in _not_ setting O_CLOEXEC when opening the event channel driver node. The caller can then obtain the file descriptor via xenevtchn_fd(). Add an alternative open function xenevtchn_fdopen() which takes that file descriptor as an additional parameter. This allows to allocate a xenevtchn_handle and to associate it with that file descriptor. Signed-off-by: Juergen Gross <jgross@suse.com> Reviewed-by: Wei Liu <wl@xen.org> Reviewed-by: Julien Grall <jgrall@amazon.com>
137 lines
2.8 KiB
C
137 lines
2.8 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, see <http://www.gnu.org/licenses/>.
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*/
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#include <errno.h>
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#include <unistd.h>
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#include <stdlib.h>
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#include "private.h"
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static int all_restrict_cb(Xentoolcore__Active_Handle *ah, domid_t domid)
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{
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xenevtchn_handle *xce = CONTAINER_OF(ah, *xce, tc_ah);
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if ( xce->fd < 0 )
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/* just in case */
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return 0;
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return xenevtchn_restrict(xce, domid);
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}
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static xenevtchn_handle *xenevtchn_alloc_handle(xentoollog_logger *logger)
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{
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xenevtchn_handle *xce = malloc(sizeof(*xce));
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if ( !xce )
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return NULL;
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xce->fd = -1;
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xce->logger = logger;
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xce->logger_tofree = NULL;
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xce->tc_ah.restrict_callback = all_restrict_cb;
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xentoolcore__register_active_handle(&xce->tc_ah);
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if ( !xce->logger )
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{
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xce->logger = xce->logger_tofree = (xentoollog_logger *)
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xtl_createlogger_stdiostream(stderr, XTL_PROGRESS, 0);
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if ( !xce->logger )
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goto err;
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}
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return xce;
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err:
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xenevtchn_close(xce);
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return NULL;
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}
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xenevtchn_handle *xenevtchn_open(xentoollog_logger *logger, unsigned int flags)
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{
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xenevtchn_handle *xce;
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int rc;
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if ( flags & ~XENEVTCHN_NO_CLOEXEC )
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{
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errno = EINVAL;
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return NULL;
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}
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xce = xenevtchn_alloc_handle(logger);
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if ( !xce )
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return NULL;
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rc = osdep_evtchn_open(xce, flags);
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if ( rc < 0 )
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goto err;
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return xce;
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err:
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xenevtchn_close(xce);
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return NULL;
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}
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xenevtchn_handle *xenevtchn_fdopen(struct xentoollog_logger *logger,
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int fd, unsigned int flags)
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{
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xenevtchn_handle *xce;
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if ( flags )
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{
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errno = EINVAL;
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return NULL;
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}
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xce = xenevtchn_alloc_handle(logger);
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if ( !xce )
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return NULL;
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xce->fd = fd;
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return xce;
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}
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int xenevtchn_close(xenevtchn_handle *xce)
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{
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int rc;
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if ( !xce )
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return 0;
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xentoolcore__deregister_active_handle(&xce->tc_ah);
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rc = osdep_evtchn_close(xce);
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xtl_logger_destroy(xce->logger_tofree);
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free(xce);
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return rc;
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}
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int xenevtchn_restrict(xenevtchn_handle *xce, domid_t domid)
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{
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return osdep_evtchn_restrict(xce, domid);
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}
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/*
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* Local variables:
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* mode: C
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* c-file-style: "BSD"
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* c-basic-offset: 4
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* tab-width: 4
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* indent-tabs-mode: nil
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* End:
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*/
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