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1 /*
2  * Copyright (C) 2008 The Android Open Source Project
3  * All rights reserved.
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted provided that the following conditions
7  * are met:
8  *  * Redistributions of source code must retain the above copyright
9  *    notice, this list of conditions and the following disclaimer.
10  *  * Redistributions in binary form must reproduce the above copyright
11  *    notice, this list of conditions and the following disclaimer in
12  *    the documentation and/or other materials provided with the
13  *    distribution.
14  *
15  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
16  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
17  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
18  * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
19  * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
20  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
21  * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
22  * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
23  * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
24  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
25  * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26  * SUCH DAMAGE.
27  */
28 #include <errno.h>
29 #include <signal.h>
30 #include <string.h>
31 #include <time.h>
32 
33 int __rt_sigtimedwait(const sigset_t *uthese, siginfo_t *uinfo, const struct timespec *uts, size_t sigsetsize);
34 
35 /* ok, this is really subtle: <asm/signal.h> defines sigset_t differently
36  * when you're in the kernel or in the C library.
37  *
38  * in the kernel, this is an array of 2 32-bit unsigned longs
39  * in the C library, this is a single 32-bit unsigned long
40  *
41  * moreover, the kernel implementation of rt_sigtimedwait doesn't
42  * accept anything except kernel-sized signal sets (probably a bug !)
43  *
44  * we thus need to create a fake kernel sigset !!
45  */
46 
sigwait(const sigset_t * set,int * sig)47 int sigwait(const sigset_t *set, int *sig)
48 {
49     int  ret;
50     /* use a union to get rid of aliasing warnings */
51     union {
52       unsigned long  kernel_sigset[2];
53       sigset_t       dummy_sigset;
54     } u;
55 
56     u.kernel_sigset[0] = *set;
57     u.kernel_sigset[1] = 0;  /* no real-time signals supported ? */
58     for (;;)
59     {
60      /* __rt_sigtimedwait can return EAGAIN or EINTR, we need to loop
61       * around them since sigwait is only allowed to return EINVAL
62       */
63       ret = __rt_sigtimedwait ( &u.dummy_sigset, NULL, NULL, sizeof(u.kernel_sigset));
64       if (ret >= 0)
65         break;
66 
67       if (errno != EAGAIN && errno != EINTR)
68         return errno;
69     }
70 
71     *sig = ret;
72     return 0;
73 }
74 
75