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Ian Jackson
9976f3874d
Closing the fd before unhooking it from the list runs the risk that a
concurrent thread calls xentoolcore_restrict_all will operate on the
old fd value, which might refer to a new fd by then. So we need to do
it in the other order.
Sadly this weakens the guarantee provided by xentoolcore_restrict_all
slightly, but not (I think) in a problematic way. It would be
possible to implement the previous guarantee, but it would involve
replacing all of the close() calls in all of the individual osdep
parts of all of the individual libraries with calls to a new function
which does
dup2("/dev/null", thing->fd);
pthread_mutex_lock(&handles_lock);
thing->fd = -1;
pthread_mutex_unlock(&handles_lock);
close(fd);
which would be terribly tedious.
Signed-off-by: Ian Jackson <Ian.Jackson@eu.citrix.com>
Acked-by: Wei Liu <wei.liu2@citrix.com>
Reviewed-by: Ross Lagerwall <ross.lagerwall@citrix.com>
Release-acked-by: Julien Grall <julien.grall@linaro.org>
141 lines
4.1 KiB
C
141 lines
4.1 KiB
C
/******************************************************************************
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*
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* Copyright (c) 2007-2008, D G Murray <Derek.Murray@cl.cam.ac.uk>
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*
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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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* Split out from xc_gnttab.c
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*/
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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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xengnttab_handle *xgt = CONTAINER_OF(ah, *xgt, tc_ah);
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return xentoolcore__restrict_by_dup2_null(xgt->fd);
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}
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xengnttab_handle *xengnttab_open(xentoollog_logger *logger, unsigned open_flags)
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{
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xengnttab_handle *xgt = malloc(sizeof(*xgt));
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int rc;
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if (!xgt) return NULL;
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xgt->fd = -1;
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xgt->logger = logger;
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xgt->logger_tofree = NULL;
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xgt->tc_ah.restrict_callback = all_restrict_cb;
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xentoolcore__register_active_handle(&xgt->tc_ah);
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if (!xgt->logger) {
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xgt->logger = xgt->logger_tofree =
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(xentoollog_logger*)
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xtl_createlogger_stdiostream(stderr, XTL_PROGRESS, 0);
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if (!xgt->logger) goto err;
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}
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rc = osdep_gnttab_open(xgt);
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if ( rc < 0 ) goto err;
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return xgt;
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err:
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xentoolcore__deregister_active_handle(&xgt->tc_ah);
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osdep_gnttab_close(xgt);
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xtl_logger_destroy(xgt->logger_tofree);
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free(xgt);
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return NULL;
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}
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int xengnttab_close(xengnttab_handle *xgt)
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{
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int rc;
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if ( !xgt )
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return 0;
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xentoolcore__deregister_active_handle(&xgt->tc_ah);
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rc = osdep_gnttab_close(xgt);
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xtl_logger_destroy(xgt->logger_tofree);
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free(xgt);
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return rc;
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}
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int xengnttab_set_max_grants(xengnttab_handle *xgt, uint32_t count)
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{
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return osdep_gnttab_set_max_grants(xgt, count);
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}
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void *xengnttab_map_grant_ref(xengnttab_handle *xgt,
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uint32_t domid,
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uint32_t ref,
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int prot)
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{
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return osdep_gnttab_grant_map(xgt, 1, 0, prot, &domid, &ref, -1, -1);
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}
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void *xengnttab_map_grant_refs(xengnttab_handle *xgt,
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uint32_t count,
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uint32_t *domids,
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uint32_t *refs,
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int prot)
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{
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return osdep_gnttab_grant_map(xgt, count, 0, prot, domids, refs, -1, -1);
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}
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void *xengnttab_map_domain_grant_refs(xengnttab_handle *xgt,
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uint32_t count,
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uint32_t domid,
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uint32_t *refs,
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int prot)
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{
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return osdep_gnttab_grant_map(xgt, count, XENGNTTAB_GRANT_MAP_SINGLE_DOMAIN,
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prot, &domid, refs, -1, -1);
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}
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void *xengnttab_map_grant_ref_notify(xengnttab_handle *xgt,
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uint32_t domid,
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uint32_t ref,
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int prot,
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uint32_t notify_offset,
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evtchn_port_t notify_port)
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{
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return osdep_gnttab_grant_map(xgt, 1, 0, prot, &domid, &ref,
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notify_offset, notify_port);
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}
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int xengnttab_unmap(xengnttab_handle *xgt, void *start_address, uint32_t count)
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{
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return osdep_gnttab_unmap(xgt, start_address, count);
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}
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int xengnttab_grant_copy(xengnttab_handle *xgt,
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uint32_t count,
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xengnttab_grant_copy_segment_t *segs)
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{
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return osdep_gnttab_grant_copy(xgt, count, segs);
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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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