xref: /netbsd-src/external/gpl3/gdb.old/dist/gdb/obsd-nat.c (revision bdc22b2e01993381dcefeff2bc9b56ca75a4235c)
1 /* Native-dependent code for OpenBSD.
2 
3    Copyright (C) 2012-2016 Free Software Foundation, Inc.
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 #include "defs.h"
21 #include "gdbthread.h"
22 #include "inferior.h"
23 #include "target.h"
24 
25 #include <sys/types.h>
26 #include <sys/ptrace.h>
27 #include "gdb_wait.h"
28 
29 #include "inf-child.h"
30 #include "obsd-nat.h"
31 
32 /* OpenBSD 5.2 and later include rthreads which uses a thread model
33    that maps userland threads directly onto kernel threads in a 1:1
34    fashion.  */
35 
36 #ifdef PT_GET_THREAD_FIRST
37 
38 static char *
39 obsd_pid_to_str (struct target_ops *ops, ptid_t ptid)
40 {
41   if (ptid_get_lwp (ptid) != 0)
42     {
43       static char buf[64];
44 
45       xsnprintf (buf, sizeof buf, "thread %ld", ptid_get_lwp (ptid));
46       return buf;
47     }
48 
49   return normal_pid_to_str (ptid);
50 }
51 
52 static void
53 obsd_update_thread_list (struct target_ops *ops)
54 {
55   pid_t pid = ptid_get_pid (inferior_ptid);
56   struct ptrace_thread_state pts;
57 
58   prune_threads ();
59 
60   if (ptrace (PT_GET_THREAD_FIRST, pid, (caddr_t)&pts, sizeof pts) == -1)
61     perror_with_name (("ptrace"));
62 
63   while (pts.pts_tid != -1)
64     {
65       ptid_t ptid = ptid_build (pid, pts.pts_tid, 0);
66 
67       if (!in_thread_list (ptid))
68 	{
69 	  if (ptid_get_lwp (inferior_ptid) == 0)
70 	    thread_change_ptid (inferior_ptid, ptid);
71 	  else
72 	    add_thread (ptid);
73 	}
74 
75       if (ptrace (PT_GET_THREAD_NEXT, pid, (caddr_t)&pts, sizeof pts) == -1)
76 	perror_with_name (("ptrace"));
77     }
78 }
79 
80 static ptid_t
81 obsd_wait (struct target_ops *ops,
82 	   ptid_t ptid, struct target_waitstatus *ourstatus, int options)
83 {
84   pid_t pid;
85   int status, save_errno;
86 
87   do
88     {
89       set_sigint_trap ();
90 
91       do
92 	{
93 	  pid = waitpid (ptid_get_pid (ptid), &status, 0);
94 	  save_errno = errno;
95 	}
96       while (pid == -1 && errno == EINTR);
97 
98       clear_sigint_trap ();
99 
100       if (pid == -1)
101 	{
102 	  fprintf_unfiltered (gdb_stderr,
103 			      _("Child process unexpectedly missing: %s.\n"),
104 			      safe_strerror (save_errno));
105 
106 	  /* Claim it exited with unknown signal.  */
107 	  ourstatus->kind = TARGET_WAITKIND_SIGNALLED;
108 	  ourstatus->value.sig = GDB_SIGNAL_UNKNOWN;
109 	  return inferior_ptid;
110 	}
111 
112       /* Ignore terminated detached child processes.  */
113       if (!WIFSTOPPED (status) && pid != ptid_get_pid (inferior_ptid))
114 	pid = -1;
115     }
116   while (pid == -1);
117 
118   ptid = pid_to_ptid (pid);
119 
120   if (WIFSTOPPED (status))
121     {
122       ptrace_state_t pe;
123       pid_t fpid;
124 
125       if (ptrace (PT_GET_PROCESS_STATE, pid, (caddr_t)&pe, sizeof pe) == -1)
126 	perror_with_name (("ptrace"));
127 
128       switch (pe.pe_report_event)
129 	{
130 	case PTRACE_FORK:
131 	  ourstatus->kind = TARGET_WAITKIND_FORKED;
132 	  ourstatus->value.related_pid = pid_to_ptid (pe.pe_other_pid);
133 
134 	  /* Make sure the other end of the fork is stopped too.  */
135 	  fpid = waitpid (pe.pe_other_pid, &status, 0);
136 	  if (fpid == -1)
137 	    perror_with_name (("waitpid"));
138 
139 	  if (ptrace (PT_GET_PROCESS_STATE, fpid,
140 		      (caddr_t)&pe, sizeof pe) == -1)
141 	    perror_with_name (("ptrace"));
142 
143 	  gdb_assert (pe.pe_report_event == PTRACE_FORK);
144 	  gdb_assert (pe.pe_other_pid == pid);
145 	  if (fpid == ptid_get_pid (inferior_ptid))
146 	    {
147 	      ourstatus->value.related_pid = pid_to_ptid (pe.pe_other_pid);
148 	      return pid_to_ptid (fpid);
149 	    }
150 
151 	  return pid_to_ptid (pid);
152 	}
153 
154       ptid = ptid_build (pid, pe.pe_tid, 0);
155       if (!in_thread_list (ptid))
156 	{
157 	  if (ptid_get_lwp (inferior_ptid) == 0)
158 	    thread_change_ptid (inferior_ptid, ptid);
159 	  else
160 	    add_thread (ptid);
161 	}
162     }
163 
164   store_waitstatus (ourstatus, status);
165   return ptid;
166 }
167 
168 void
169 obsd_add_target (struct target_ops *t)
170 {
171   /* Override some methods to support threads.  */
172   t->to_pid_to_str = obsd_pid_to_str;
173   t->to_update_thread_list = obsd_update_thread_list;
174   t->to_wait = obsd_wait;
175   add_target (t);
176 }
177 
178 #else
179 
180 void
181 obsd_add_target (struct target_ops *t)
182 {
183   add_target (t);
184 }
185 
186 #endif /* PT_GET_THREAD_FIRST */
187