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96d7229d LM |
1 | /* Wrapper implementation for waitpid for GNU/Linux (LWP layer). |
2 | ||
ecd75fc8 | 3 | Copyright (C) 2001-2014 Free Software Foundation, Inc. |
96d7229d LM |
4 | |
5 | This file is part of GDB. | |
6 | ||
7 | This program is free software; you can redistribute it and/or modify | |
8 | it under the terms of the GNU General Public License as published by | |
9 | the Free Software Foundation; either version 3 of the License, or | |
10 | (at your option) any later version. | |
11 | ||
12 | This program is distributed in the hope that it will be useful, | |
13 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
14 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
15 | GNU General Public License for more details. | |
16 | ||
17 | You should have received a copy of the GNU General Public License | |
18 | along with this program. If not, see <http://www.gnu.org/licenses/>. */ | |
19 | ||
20 | #ifdef GDBSERVER | |
21 | #include "server.h" | |
22 | #else | |
23 | #include "defs.h" | |
24 | #include "signal.h" | |
25 | #endif | |
26 | ||
27 | #include "nat/linux-nat.h" | |
28 | #include "nat/linux-waitpid.h" | |
29 | #include "gdb_wait.h" | |
30 | ||
31 | /* Print debugging output based on the format string FORMAT and | |
32 | its parameters. */ | |
33 | ||
34 | static inline void | |
35 | linux_debug (const char *format, ...) | |
36 | { | |
37 | #ifdef GDBSERVER | |
38 | if (debug_threads) | |
39 | { | |
40 | va_list args; | |
41 | va_start (args, format); | |
42 | vfprintf (stderr, format, args); | |
96d7229d LM |
43 | va_end (args); |
44 | } | |
45 | #else | |
46 | /* GDB-specific debugging output. */ | |
47 | #endif | |
48 | } | |
49 | ||
50 | /* Wrapper function for waitpid which handles EINTR, and emulates | |
51 | __WALL for systems where that is not available. */ | |
52 | ||
53 | int | |
54 | my_waitpid (int pid, int *status, int flags) | |
55 | { | |
56 | int ret, out_errno; | |
57 | ||
58 | linux_debug ("my_waitpid (%d, 0x%x)\n", pid, flags); | |
59 | ||
60 | if (flags & __WALL) | |
61 | { | |
62 | sigset_t block_mask, org_mask, wake_mask; | |
63 | int wnohang; | |
64 | ||
65 | wnohang = (flags & WNOHANG) != 0; | |
66 | flags &= ~(__WALL | __WCLONE); | |
67 | flags |= WNOHANG; | |
68 | ||
69 | /* Block all signals while here. This avoids knowing about | |
70 | LinuxThread's signals. */ | |
71 | sigfillset (&block_mask); | |
72 | sigprocmask (SIG_BLOCK, &block_mask, &org_mask); | |
73 | ||
74 | /* ... except during the sigsuspend below. */ | |
75 | sigemptyset (&wake_mask); | |
76 | ||
77 | while (1) | |
78 | { | |
79 | /* Since all signals are blocked, there's no need to check | |
80 | for EINTR here. */ | |
81 | ret = waitpid (pid, status, flags); | |
82 | out_errno = errno; | |
83 | ||
84 | if (ret == -1 && out_errno != ECHILD) | |
85 | break; | |
86 | else if (ret > 0) | |
87 | break; | |
88 | ||
89 | if (flags & __WCLONE) | |
90 | { | |
91 | /* We've tried both flavors now. If WNOHANG is set, | |
92 | there's nothing else to do, just bail out. */ | |
93 | if (wnohang) | |
94 | break; | |
95 | ||
96 | linux_debug ("blocking\n"); | |
97 | ||
98 | /* Block waiting for signals. */ | |
99 | sigsuspend (&wake_mask); | |
100 | } | |
101 | flags ^= __WCLONE; | |
102 | } | |
103 | ||
104 | sigprocmask (SIG_SETMASK, &org_mask, NULL); | |
105 | } | |
106 | else | |
107 | { | |
108 | do | |
109 | ret = waitpid (pid, status, flags); | |
110 | while (ret == -1 && errno == EINTR); | |
111 | out_errno = errno; | |
112 | } | |
113 | ||
114 | linux_debug ("my_waitpid (%d, 0x%x): status(%x), %d\n", | |
115 | pid, flags, status ? *status : -1, ret); | |
116 | ||
117 | errno = out_errno; | |
118 | return ret; | |
119 | } |