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3993f6b1 DJ |
1 | /* GNU/Linux native-dependent code common to multiple platforms. |
2 | Copyright (C) 2003 Free Software Foundation, Inc. | |
3 | ||
4 | This file is part of GDB. | |
5 | ||
6 | This program is free software; you can redistribute it and/or modify | |
7 | it under the terms of the GNU General Public License as published by | |
8 | the Free Software Foundation; either version 2 of the License, or | |
9 | (at your option) any later version. | |
10 | ||
11 | This program is distributed in the hope that it will be useful, | |
12 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
13 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
14 | GNU General Public License for more details. | |
15 | ||
16 | You should have received a copy of the GNU General Public License | |
17 | along with this program; if not, write to the Free Software | |
18 | Foundation, Inc., 59 Temple Place - Suite 330, | |
19 | Boston, MA 02111-1307, USA. */ | |
20 | ||
21 | #include "defs.h" | |
22 | #include "inferior.h" | |
23 | #include "target.h" | |
24 | ||
25 | #include "gdb_wait.h" | |
26 | #include <sys/ptrace.h> | |
27 | ||
0274a8ce MS |
28 | #include "linux-nat.h" |
29 | ||
3993f6b1 DJ |
30 | /* If the system headers did not provide the constants, hard-code the normal |
31 | values. */ | |
32 | #ifndef PTRACE_EVENT_FORK | |
33 | ||
34 | #define PTRACE_SETOPTIONS 0x4200 | |
35 | #define PTRACE_GETEVENTMSG 0x4201 | |
36 | ||
37 | /* options set using PTRACE_SETOPTIONS */ | |
38 | #define PTRACE_O_TRACESYSGOOD 0x00000001 | |
39 | #define PTRACE_O_TRACEFORK 0x00000002 | |
40 | #define PTRACE_O_TRACEVFORK 0x00000004 | |
41 | #define PTRACE_O_TRACECLONE 0x00000008 | |
42 | #define PTRACE_O_TRACEEXEC 0x00000010 | |
43 | ||
44 | /* Wait extended result codes for the above trace options. */ | |
45 | #define PTRACE_EVENT_FORK 1 | |
46 | #define PTRACE_EVENT_VFORK 2 | |
47 | #define PTRACE_EVENT_CLONE 3 | |
48 | #define PTRACE_EVENT_EXEC 4 | |
49 | ||
50 | #endif /* PTRACE_EVENT_FORK */ | |
51 | ||
52 | /* We can't always assume that this flag is available, but all systems | |
53 | with the ptrace event handlers also have __WALL, so it's safe to use | |
54 | here. */ | |
55 | #ifndef __WALL | |
56 | #define __WALL 0x40000000 /* Wait for any child. */ | |
57 | #endif | |
58 | ||
ae087d01 DJ |
59 | struct simple_pid_list |
60 | { | |
61 | int pid; | |
62 | struct simple_pid_list *next; | |
63 | }; | |
64 | struct simple_pid_list *stopped_pids; | |
65 | ||
3993f6b1 DJ |
66 | /* This variable is a tri-state flag: -1 for unknown, 0 if PTRACE_O_TRACEFORK |
67 | can not be used, 1 if it can. */ | |
68 | ||
69 | static int linux_supports_tracefork_flag = -1; | |
70 | ||
ae087d01 DJ |
71 | \f |
72 | /* Trivial list manipulation functions to keep track of a list of | |
73 | new stopped processes. */ | |
74 | static void | |
75 | add_to_pid_list (struct simple_pid_list **listp, int pid) | |
76 | { | |
77 | struct simple_pid_list *new_pid = xmalloc (sizeof (struct simple_pid_list)); | |
78 | new_pid->pid = pid; | |
79 | new_pid->next = *listp; | |
80 | *listp = new_pid; | |
81 | } | |
82 | ||
83 | static int | |
84 | pull_pid_from_list (struct simple_pid_list **listp, int pid) | |
85 | { | |
86 | struct simple_pid_list **p; | |
87 | ||
88 | for (p = listp; *p != NULL; p = &(*p)->next) | |
89 | if ((*p)->pid == pid) | |
90 | { | |
91 | struct simple_pid_list *next = (*p)->next; | |
92 | xfree (*p); | |
93 | *p = next; | |
94 | return 1; | |
95 | } | |
96 | return 0; | |
97 | } | |
98 | ||
99 | void | |
100 | linux_record_stopped_pid (int pid) | |
101 | { | |
102 | add_to_pid_list (&stopped_pids, pid); | |
103 | } | |
104 | ||
3993f6b1 DJ |
105 | \f |
106 | /* A helper function for linux_test_for_tracefork, called after fork (). */ | |
107 | ||
108 | static void | |
109 | linux_tracefork_child (void) | |
110 | { | |
111 | int ret; | |
112 | ||
113 | ptrace (PTRACE_TRACEME, 0, 0, 0); | |
114 | kill (getpid (), SIGSTOP); | |
115 | fork (); | |
116 | exit (0); | |
117 | } | |
118 | ||
119 | /* Determine if PTRACE_O_TRACEFORK can be used to follow fork events. We | |
120 | create a child process, attach to it, use PTRACE_SETOPTIONS to enable | |
121 | fork tracing, and let it fork. If the process exits, we assume that | |
122 | we can't use TRACEFORK; if we get the fork notification, and we can | |
123 | extract the new child's PID, then we assume that we can. */ | |
124 | ||
125 | static void | |
126 | linux_test_for_tracefork (void) | |
127 | { | |
128 | int child_pid, ret, status; | |
129 | long second_pid; | |
130 | ||
131 | child_pid = fork (); | |
132 | if (child_pid == -1) | |
133 | perror_with_name ("linux_test_for_tracefork: fork"); | |
134 | ||
135 | if (child_pid == 0) | |
136 | linux_tracefork_child (); | |
137 | ||
138 | ret = waitpid (child_pid, &status, 0); | |
139 | if (ret == -1) | |
140 | perror_with_name ("linux_test_for_tracefork: waitpid"); | |
141 | else if (ret != child_pid) | |
142 | error ("linux_test_for_tracefork: waitpid: unexpected result %d.", ret); | |
143 | if (! WIFSTOPPED (status)) | |
144 | error ("linux_test_for_tracefork: waitpid: unexpected status %d.", status); | |
145 | ||
146 | linux_supports_tracefork_flag = 0; | |
147 | ||
148 | ret = ptrace (PTRACE_SETOPTIONS, child_pid, 0, PTRACE_O_TRACEFORK); | |
149 | if (ret != 0) | |
150 | { | |
151 | ptrace (PTRACE_KILL, child_pid, 0, 0); | |
152 | waitpid (child_pid, &status, 0); | |
153 | return; | |
154 | } | |
155 | ||
156 | ptrace (PTRACE_CONT, child_pid, 0, 0); | |
157 | ret = waitpid (child_pid, &status, 0); | |
158 | if (ret == child_pid && WIFSTOPPED (status) | |
159 | && status >> 16 == PTRACE_EVENT_FORK) | |
160 | { | |
161 | second_pid = 0; | |
162 | ret = ptrace (PTRACE_GETEVENTMSG, child_pid, 0, &second_pid); | |
163 | if (ret == 0 && second_pid != 0) | |
164 | { | |
165 | int second_status; | |
166 | ||
167 | linux_supports_tracefork_flag = 1; | |
168 | waitpid (second_pid, &second_status, 0); | |
169 | ptrace (PTRACE_DETACH, second_pid, 0, 0); | |
170 | } | |
171 | } | |
172 | ||
173 | if (WIFSTOPPED (status)) | |
174 | { | |
175 | ptrace (PTRACE_DETACH, child_pid, 0, 0); | |
176 | waitpid (child_pid, &status, 0); | |
177 | } | |
178 | } | |
179 | ||
180 | /* Return non-zero iff we have tracefork functionality available. | |
181 | This function also sets linux_supports_tracefork_flag. */ | |
182 | ||
183 | static int | |
184 | linux_supports_tracefork (void) | |
185 | { | |
186 | if (linux_supports_tracefork_flag == -1) | |
187 | linux_test_for_tracefork (); | |
188 | return linux_supports_tracefork_flag; | |
189 | } | |
190 | ||
191 | \f | |
192 | int | |
193 | child_insert_fork_catchpoint (int pid) | |
194 | { | |
195 | if (linux_supports_tracefork ()) | |
196 | error ("Fork catchpoints have not been implemented yet."); | |
197 | else | |
198 | error ("Your system does not support fork catchpoints."); | |
199 | } | |
200 | ||
201 | int | |
202 | child_insert_vfork_catchpoint (int pid) | |
203 | { | |
204 | if (linux_supports_tracefork ()) | |
205 | error ("Vfork catchpoints have not been implemented yet."); | |
206 | else | |
207 | error ("Your system does not support vfork catchpoints."); | |
208 | } | |
209 | ||
210 | int | |
211 | child_insert_exec_catchpoint (int pid) | |
212 | { | |
213 | if (linux_supports_tracefork ()) | |
214 | error ("Exec catchpoints have not been implemented yet."); | |
215 | else | |
216 | error ("Your system does not support exec catchpoints."); | |
217 | } | |
218 | ||
219 |