1 /*
2 * Copyright (c) 2019 The DragonFly Project. All rights reserved.
3 *
4 * This code is derived from software contributed to The DragonFly Project
5 * by Matthew Dillon <dillon@backplane.com>
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 *
11 * 1. Redistributions of source code must retain the above copyright
12 * notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 * notice, this list of conditions and the following disclaimer in
15 * the documentation and/or other materials provided with the
16 * distribution.
17 * 3. Neither the name of The DragonFly Project nor the names of its
18 * contributors may be used to endorse or promote products derived
19 * from this software without specific, prior written permission.
20 *
21 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
22 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
23 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
24 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
25 * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
26 * INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING,
27 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
28 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
29 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
30 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
31 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32 * SUCH DAMAGE.
33 */
34
35 #include "namespace.h"
36 #include <sys/cdefs.h>
37 #include <sys/types.h>
38 #include <sys/syscall.h>
39 #include <sys/time.h>
40 #include <machine/cpufunc.h>
41 #include <machine/atomic.h>
42 #include <errno.h>
43 #include <time.h>
44 #include <stdio.h>
45 #include <unistd.h>
46 #include "un-namespace.h"
47 #include "libc_private.h"
48 #include "upmap.h"
49
50 int _sigblockall(void);
51 int _sigunblockall(void);
52 int __getpid(void);
53 pid_t __sys_getpid(void);
54
55 /*
56 * Block all maskable signals to this thread. Does not prevent signal
57 * delivery to the thread's pending signal mask, but does prevent signal
58 * dispatch.
59 *
60 * Reentrant, returns the reentrancy count. First call will thus return
61 * 1. -1 is returned if the feature is not supported.
62 *
63 * The pointer is set-up on program startup and will remain valid on fork()
64 * (the kernel will re-fault the proper page). On vfork(), however, the
65 * pointer points to the parent thread's mapping.
66 */
67 int
_sigblockall(void)68 _sigblockall(void)
69 {
70 if (__lpmap_blockallsigs)
71 return atomic_fetchadd_int(__lpmap_blockallsigs, 1) + 1;
72 return -1;
73 }
74
75 /*
76 * Reverse the effects of sigblockall(). Returns the reentrancy count
77 * after decrement. -1 is returned if not supported.
78 *
79 * Bit 31 is set on return if signals were received while blocked. Upon
80 * last unblock this bit also indicates that pending service routines ran.
81 * The bit is cumulative until the last unblock occurs.
82 */
83 int
_sigunblockall(void)84 _sigunblockall(void)
85 {
86 uint32_t bas;
87
88 if (__lpmap_blockallsigs) {
89 bas = atomic_fetchadd_int(__lpmap_blockallsigs, -1) - 1;
90 if (bas == 0x80000000U) {
91 (void)__sys_getpid(); /* force signal processing */
92 atomic_clear_int(__lpmap_blockallsigs, 0x80000000U);
93 }
94 return (int)bas;
95 }
96 return -1;
97 }
98
99 __weak_reference(_sigblockall, sigblockall);
100 __weak_reference(_sigunblockall, sigunblockall);
101