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git.proxmox.com Git - mirror_lxc.git/blob - src/lxc/sync.c
2 * lxc: linux Container library
4 * (C) Copyright IBM Corp. 2007, 2008
7 * Daniel Lezcano <daniel.lezcano at free.fr>
9 * This library is free software; you can redistribute it and/or
10 * modify it under the terms of the GNU Lesser General Public
11 * License as published by the Free Software Foundation; either
12 * version 2.1 of the License, or (at your option) any later version.
14 * This library is distributed in the hope that it will be useful,
15 * but WITHOUT ANY WARRANTY; without even the implied warranty of
16 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
17 * Lesser General Public License for more details.
19 * You should have received a copy of the GNU Lesser General Public
20 * License along with this library; if not, write to the Free Software
21 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
24 #include <sys/types.h>
25 #include <sys/socket.h>
33 lxc_log_define(lxc_sync
, lxc
);
35 static int __sync_wait(int fd
, int sequence
)
40 ret
= read(fd
, &sync
, sizeof(sync
));
42 ERROR("sync wait failure : %m");
49 if (sync
!= sequence
) {
50 ERROR("invalid sequence number %d. expected %d",
57 static int __sync_wake(int fd
, int sequence
)
61 if (write(fd
, &sync
, sizeof(sync
)) < 0) {
62 ERROR("sync wake failure : %m");
68 static int __sync_barrier(int fd
, int sequence
)
70 if (__sync_wake(fd
, sequence
))
72 return __sync_wait(fd
, sequence
+1);
75 int lxc_sync_barrier_parent(struct lxc_handler
*handler
, int sequence
)
77 return __sync_barrier(handler
->sv
[0], sequence
);
80 int lxc_sync_barrier_child(struct lxc_handler
*handler
, int sequence
)
82 return __sync_barrier(handler
->sv
[1], sequence
);
85 int lxc_sync_wake_parent(struct lxc_handler
*handler
, int sequence
)
87 return __sync_wake(handler
->sv
[0], sequence
);
90 int lxc_sync_wait_child(struct lxc_handler
*handler
, int sequence
)
92 return __sync_wait(handler
->sv
[1], sequence
);
95 int lxc_sync_wake_child(struct lxc_handler
*handler
, int sequence
)
97 return __sync_wake(handler
->sv
[1], sequence
);
100 int lxc_sync_init(struct lxc_handler
*handler
)
104 ret
= socketpair(AF_LOCAL
, SOCK_STREAM
, 0, handler
->sv
);
106 SYSERROR("failed to create synchronization socketpair");
110 /* Be sure we don't inherit this after the exec */
111 fcntl(handler
->sv
[0], F_SETFD
, FD_CLOEXEC
);
116 void lxc_sync_fini_child(struct lxc_handler
*handler
)
118 if (handler
->sv
[0] != -1) {
119 close(handler
->sv
[0]);
124 void lxc_sync_fini_parent(struct lxc_handler
*handler
)
126 if (handler
->sv
[1] != -1) {
127 close(handler
->sv
[1]);
132 void lxc_sync_fini(struct lxc_handler
*handler
)
134 lxc_sync_fini_child(handler
);
135 lxc_sync_fini_parent(handler
);