xref: /netbsd-src/external/gpl3/gdb.old/dist/gdb/obsd-nat.c (revision 8e33eff89e26cf71871ead62f0d5063e1313c33a)
1 /* Native-dependent code for OpenBSD.
2 
3    Copyright (C) 2012-2023 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 "gdbsupport/gdb_wait.h"
28 
29 #include "inf-ptrace.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 std::string
37 obsd_nat_target::pid_to_str (ptid_t ptid)
38 {
39   if (ptid.lwp () != 0)
40     return string_printf ("thread %ld of process %d", ptid.lwp (), ptid.pid ());
41 
42   return normal_pid_to_str (ptid);
43 }
44 
45 void
46 obsd_nat_target::update_thread_list ()
47 {
48   pid_t pid = inferior_ptid.pid ();
49   struct ptrace_thread_state pts;
50 
51   prune_threads ();
52 
53   if (ptrace (PT_GET_THREAD_FIRST, pid, (caddr_t)&pts, sizeof pts) == -1)
54     perror_with_name (("ptrace"));
55 
56   while (pts.pts_tid != -1)
57     {
58       ptid_t ptid = ptid_t (pid, pts.pts_tid, 0);
59 
60       if (!in_thread_list (this, ptid))
61 	{
62 	  if (inferior_ptid.lwp () == 0)
63 	    thread_change_ptid (this, inferior_ptid, ptid);
64 	  else
65 	    add_thread (this, ptid);
66 	}
67 
68       if (ptrace (PT_GET_THREAD_NEXT, pid, (caddr_t)&pts, sizeof pts) == -1)
69 	perror_with_name (("ptrace"));
70     }
71 }
72 
73 /* Enable additional event reporting on a new or existing process.  */
74 
75 static void
76 obsd_enable_proc_events (pid_t pid)
77 {
78   ptrace_event_t pe;
79 
80   /* Set the initial event mask.  */
81   memset (&pe, 0, sizeof pe);
82   pe.pe_set_event |= PTRACE_FORK;
83   if (ptrace (PT_SET_EVENT_MASK, pid,
84 	      (PTRACE_TYPE_ARG3)&pe, sizeof pe) == -1)
85     perror_with_name (("ptrace"));
86 }
87 
88 ptid_t
89 obsd_nat_target::wait (ptid_t ptid, struct target_waitstatus *ourstatus,
90 		       target_wait_flags options)
91 {
92   ptid_t wptid = inf_ptrace_target::wait (ptid, ourstatus, options);
93   if (ourstatus->kind () == TARGET_WAITKIND_STOPPED)
94     {
95       ptrace_state_t pe;
96 
97       pid_t pid = wptid.pid ();
98       if (ptrace (PT_GET_PROCESS_STATE, pid, (caddr_t)&pe, sizeof pe) == -1)
99 	perror_with_name (("ptrace"));
100 
101       wptid = ptid_t (pid, pe.pe_tid, 0);
102 
103       switch (pe.pe_report_event)
104 	{
105 	case PTRACE_FORK:
106 	  ourstatus->set_forked (ptid_t (pe.pe_other_pid));
107 
108 	  /* Make sure the other end of the fork is stopped too.  */
109 	  pid_t fpid = waitpid (pe.pe_other_pid, nullptr, 0);
110 	  if (fpid == -1)
111 	    perror_with_name (("waitpid"));
112 
113 	  if (ptrace (PT_GET_PROCESS_STATE, fpid,
114 		      (caddr_t)&pe, sizeof pe) == -1)
115 	    perror_with_name (("ptrace"));
116 
117 	  gdb_assert (pe.pe_report_event == PTRACE_FORK);
118 	  gdb_assert (pe.pe_other_pid == pid);
119 	  if (find_inferior_pid (this, fpid) != nullptr)
120 	    {
121 	      ourstatus->set_forked (ptid_t (pe.pe_other_pid));
122 	      wptid = ptid_t (fpid, pe.pe_tid, 0);
123 	    }
124 
125 	  obsd_enable_proc_events (ourstatus->child_ptid ().pid ());
126 	  break;
127 	}
128 
129       /* Ensure the ptid is updated with an LWP id on the first stop
130          of a process.  */
131       if (!in_thread_list (this, wptid))
132 	{
133 	  if (in_thread_list (this, ptid_t (pid)))
134 	    thread_change_ptid (this, ptid_t (pid), wptid);
135 	  else
136 	    add_thread (this, wptid);
137 	}
138     }
139   return wptid;
140 }
141 
142 void
143 obsd_nat_target::post_attach (int pid)
144 {
145   obsd_enable_proc_events (pid);
146 }
147 
148 /* Implement the virtual inf_ptrace_target::post_startup_inferior method.  */
149 
150 void
151 obsd_nat_target::post_startup_inferior (ptid_t pid)
152 {
153   obsd_enable_proc_events (pid.pid ());
154 }
155 
156 /* Target hook for follow_fork.  */
157 
158 void
159 obsd_nat_target::follow_fork (inferior *child_inf, ptid_t child_ptid,
160 			      target_waitkind fork_kind,
161 			      bool follow_child, bool detach_fork)
162 {
163   inf_ptrace_target::follow_fork (child_inf, child_ptid, fork_kind,
164 				  follow_child, detach_fork);
165 
166   if (!follow_child && detach_fork)
167     {
168       /* Breakpoints have already been detached from the child by
169 	 infrun.c.  */
170 
171       if (ptrace (PT_DETACH, child_ptid.pid (), (PTRACE_TYPE_ARG3)1, 0) == -1)
172 	perror_with_name (("ptrace"));
173     }
174 }
175 
176 int
177 obsd_nat_target::insert_fork_catchpoint (int pid)
178 {
179   return 0;
180 }
181 
182 int
183 obsd_nat_target::remove_fork_catchpoint (int pid)
184 {
185   return 0;
186 }
187