gdb/obsd-nat.c

   1 /* Native-dependent code for OpenBSD.
   2
   3    Copyright (C) 2012-2024 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 "gdbthread.h"
  21 #include "inferior.h"
  22 #include "target.h"
  23
  24 #include <sys/types.h>
  25 #include <sys/ptrace.h>
  26 #include "gdbsupport/gdb_wait.h"
  27
  28 #include "inf-ptrace.h"
  29 #include "obsd-nat.h"
  30
  31 /* OpenBSD 5.2 and later include rthreads which uses a thread model
  32    that maps userland threads directly onto kernel threads in a 1:1
  33    fashion.  */
  34
  35 std::string
  36 obsd_nat_target::pid_to_str (ptid_t ptid)
  37 {
  38   if (ptid.lwp () != 0)
  39     return string_printf ("thread %ld of process %d", ptid.lwp (), ptid.pid ());
  40
  41   return normal_pid_to_str (ptid);
  42 }
  43
  44 void
  45 obsd_nat_target::update_thread_list ()
  46 {
  47   pid_t pid = inferior_ptid.pid ();
  48   struct ptrace_thread_state pts;
  49
  50   prune_threads ();
  51
  52   if (ptrace (PT_GET_THREAD_FIRST, pid, (caddr_t)&pts, sizeof pts) == -1)
  53     perror_with_name (("ptrace"));
  54
  55   while (pts.pts_tid != -1)
  56     {
  57       ptid_t ptid = ptid_t (pid, pts.pts_tid, 0);
  58
  59       if (!in_thread_list (this, ptid))
  60         {
  61           if (inferior_ptid.lwp () == 0)
  62             thread_change_ptid (this, inferior_ptid, ptid);
  63           else
  64             add_thread (this, ptid);
  65         }
  66
  67       if (ptrace (PT_GET_THREAD_NEXT, pid, (caddr_t)&pts, sizeof pts) == -1)
  68         perror_with_name (("ptrace"));
  69     }
  70 }
  71
  72 /* Enable additional event reporting on a new or existing process.  */
  73
  74 static void
  75 obsd_enable_proc_events (pid_t pid)
  76 {
  77   ptrace_event_t pe;
  78
  79   /* Set the initial event mask.  */
  80   memset (&pe, 0, sizeof pe);
  81   pe.pe_set_event |= PTRACE_FORK;
  82   if (ptrace (PT_SET_EVENT_MASK, pid,
  83               (PTRACE_TYPE_ARG3)&pe, sizeof pe) == -1)
  84     perror_with_name (("ptrace"));
  85 }
  86
  87 ptid_t
  88 obsd_nat_target::wait (ptid_t ptid, struct target_waitstatus *ourstatus,
  89                        target_wait_flags options)
  90 {
  91   ptid_t wptid = inf_ptrace_target::wait (ptid, ourstatus, options);
  92   if (ourstatus->kind () == TARGET_WAITKIND_STOPPED)
  93     {
  94       ptrace_state_t pe;
  95
  96       pid_t pid = wptid.pid ();
  97       if (ptrace (PT_GET_PROCESS_STATE, pid, (caddr_t)&pe, sizeof pe) == -1)
  98         perror_with_name (("ptrace"));
  99
 100       wptid = ptid_t (pid, pe.pe_tid, 0);
 101
 102       switch (pe.pe_report_event)
 103         {
 104         case PTRACE_FORK:
 105           ourstatus->set_forked (ptid_t (pe.pe_other_pid));
 106
 107           /* Make sure the other end of the fork is stopped too.  */
 108           pid_t fpid = waitpid (pe.pe_other_pid, nullptr, 0);
 109           if (fpid == -1)
 110             perror_with_name (("waitpid"));
 111
 112           if (ptrace (PT_GET_PROCESS_STATE, fpid,
 113                       (caddr_t)&pe, sizeof pe) == -1)
 114             perror_with_name (("ptrace"));
 115
 116           gdb_assert (pe.pe_report_event == PTRACE_FORK);
 117           gdb_assert (pe.pe_other_pid == pid);
 118           if (find_inferior_pid (this, fpid) != nullptr)
 119             {
 120               ourstatus->set_forked (ptid_t (pe.pe_other_pid));
 121               wptid = ptid_t (fpid, pe.pe_tid, 0);
 122             }
 123
 124           obsd_enable_proc_events (ourstatus->child_ptid ().pid ());
 125           break;
 126         }
 127
 128       /* Ensure the ptid is updated with an LWP id on the first stop
 129          of a process.  */
 130       if (!in_thread_list (this, wptid))
 131         {
 132           if (in_thread_list (this, ptid_t (pid)))
 133             thread_change_ptid (this, ptid_t (pid), wptid);
 134           else
 135             add_thread (this, wptid);
 136         }
 137     }
 138   return wptid;
 139 }
 140
 141 void
 142 obsd_nat_target::post_attach (int pid)
 143 {
 144   obsd_enable_proc_events (pid);
 145 }
 146
 147 /* Implement the virtual inf_ptrace_target::post_startup_inferior method.  */
 148
 149 void
 150 obsd_nat_target::post_startup_inferior (ptid_t pid)
 151 {
 152   obsd_enable_proc_events (pid.pid ());
 153 }
 154
 155 /* Target hook for follow_fork.  */
 156
 157 void
 158 obsd_nat_target::follow_fork (inferior *child_inf, ptid_t child_ptid,
 159                               target_waitkind fork_kind,
 160                               bool follow_child, bool detach_fork)
 161 {
 162   inf_ptrace_target::follow_fork (child_inf, child_ptid, fork_kind,
 163                                   follow_child, detach_fork);
 164
 165   if (!follow_child && detach_fork)
 166     {
 167       /* Breakpoints have already been detached from the child by
 168          infrun.c.  */
 169
 170       if (ptrace (PT_DETACH, child_ptid.pid (), (PTRACE_TYPE_ARG3)1, 0) == -1)
 171         perror_with_name (("ptrace"));
 172     }
 173 }
 174
 175 int
 176 obsd_nat_target::insert_fork_catchpoint (int pid)
 177 {
 178   return 0;
 179 }
 180
 181 int
 182 obsd_nat_target::remove_fork_catchpoint (int pid)
 183 {
 184   return 0;
 185 }