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96d7229d LM |
1 | /* Wrapper implementation for waitpid for GNU/Linux (LWP layer). |
2 | ||
32d0add0 | 3 | Copyright (C) 2001-2015 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 | ||
b006a80e GB |
20 | #include "common-defs.h" |
21 | ||
96d7229d | 22 | #ifdef GDBSERVER |
b006a80e GB |
23 | /* FIXME: server.h is required for the definition of debug_threads |
24 | which is used in the gdbserver-specific debug printing in | |
25 | linux_debug. This code should be made available to GDB also, | |
26 | but the lack of a suitable flag to enable it prevents this. */ | |
96d7229d | 27 | #include "server.h" |
96d7229d LM |
28 | #endif |
29 | ||
125f8a3d GB |
30 | #include "linux-nat.h" |
31 | #include "linux-waitpid.h" | |
96d7229d LM |
32 | #include "gdb_wait.h" |
33 | ||
34 | /* Print debugging output based on the format string FORMAT and | |
35 | its parameters. */ | |
36 | ||
37 | static inline void | |
38 | linux_debug (const char *format, ...) | |
39 | { | |
40 | #ifdef GDBSERVER | |
41 | if (debug_threads) | |
42 | { | |
43 | va_list args; | |
44 | va_start (args, format); | |
45 | vfprintf (stderr, format, args); | |
96d7229d LM |
46 | va_end (args); |
47 | } | |
96d7229d LM |
48 | #endif |
49 | } | |
50 | ||
d632a097 PA |
51 | /* Convert wait status STATUS to a string. Used for printing debug |
52 | messages only. */ | |
53 | ||
54 | char * | |
55 | status_to_str (int status) | |
56 | { | |
57 | static char buf[64]; | |
58 | ||
59 | if (WIFSTOPPED (status)) | |
60 | { | |
61 | if (WSTOPSIG (status) == SYSCALL_SIGTRAP) | |
62 | snprintf (buf, sizeof (buf), "%s (stopped at syscall)", | |
63 | strsignal (SIGTRAP)); | |
64 | else | |
65 | snprintf (buf, sizeof (buf), "%s (stopped)", | |
66 | strsignal (WSTOPSIG (status))); | |
67 | } | |
68 | else if (WIFSIGNALED (status)) | |
69 | snprintf (buf, sizeof (buf), "%s (terminated)", | |
70 | strsignal (WTERMSIG (status))); | |
71 | else | |
72 | snprintf (buf, sizeof (buf), "%d (exited)", WEXITSTATUS (status)); | |
73 | ||
74 | return buf; | |
75 | } | |
76 | ||
96d7229d LM |
77 | /* Wrapper function for waitpid which handles EINTR, and emulates |
78 | __WALL for systems where that is not available. */ | |
79 | ||
80 | int | |
81 | my_waitpid (int pid, int *status, int flags) | |
82 | { | |
83 | int ret, out_errno; | |
84 | ||
85 | linux_debug ("my_waitpid (%d, 0x%x)\n", pid, flags); | |
86 | ||
87 | if (flags & __WALL) | |
88 | { | |
89 | sigset_t block_mask, org_mask, wake_mask; | |
90 | int wnohang; | |
91 | ||
92 | wnohang = (flags & WNOHANG) != 0; | |
93 | flags &= ~(__WALL | __WCLONE); | |
96d7229d | 94 | |
2fa0369e PA |
95 | if (!wnohang) |
96 | { | |
97 | flags |= WNOHANG; | |
98 | ||
99 | /* Block all signals while here. This avoids knowing about | |
100 | LinuxThread's signals. */ | |
101 | sigfillset (&block_mask); | |
102 | sigprocmask (SIG_BLOCK, &block_mask, &org_mask); | |
96d7229d | 103 | |
2fa0369e PA |
104 | /* ... except during the sigsuspend below. */ |
105 | sigemptyset (&wake_mask); | |
106 | } | |
96d7229d LM |
107 | |
108 | while (1) | |
109 | { | |
110 | /* Since all signals are blocked, there's no need to check | |
111 | for EINTR here. */ | |
112 | ret = waitpid (pid, status, flags); | |
113 | out_errno = errno; | |
114 | ||
115 | if (ret == -1 && out_errno != ECHILD) | |
116 | break; | |
117 | else if (ret > 0) | |
118 | break; | |
119 | ||
120 | if (flags & __WCLONE) | |
121 | { | |
122 | /* We've tried both flavors now. If WNOHANG is set, | |
123 | there's nothing else to do, just bail out. */ | |
124 | if (wnohang) | |
125 | break; | |
126 | ||
127 | linux_debug ("blocking\n"); | |
128 | ||
129 | /* Block waiting for signals. */ | |
130 | sigsuspend (&wake_mask); | |
131 | } | |
132 | flags ^= __WCLONE; | |
133 | } | |
134 | ||
2fa0369e PA |
135 | if (!wnohang) |
136 | sigprocmask (SIG_SETMASK, &org_mask, NULL); | |
96d7229d LM |
137 | } |
138 | else | |
139 | { | |
140 | do | |
141 | ret = waitpid (pid, status, flags); | |
142 | while (ret == -1 && errno == EINTR); | |
143 | out_errno = errno; | |
144 | } | |
145 | ||
146 | linux_debug ("my_waitpid (%d, 0x%x): status(%x), %d\n", | |
bf47e248 | 147 | pid, flags, (ret > 0 && status != NULL) ? *status : -1, ret); |
96d7229d LM |
148 | |
149 | errno = out_errno; | |
150 | return ret; | |
151 | } |