gdb/obsd-nat.c

   1 /* Native-dependent code for OpenBSD.
   2
   3    Copyright (C) 2012-2021 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->kind = TARGET_WAITKIND_FORKED;
 107           ourstatus->value.related_pid = ptid_t (pe.pe_other_pid);
 108
 109           /* Make sure the other end of the fork is stopped too.  */
 110           pid_t fpid = waitpid (pe.pe_other_pid, nullptr, 0);
 111           if (fpid == -1)
 112             perror_with_name (("waitpid"));
 113
 114           if (ptrace (PT_GET_PROCESS_STATE, fpid,
 115                       (caddr_t)&pe, sizeof pe) == -1)
 116             perror_with_name (("ptrace"));
 117
 118           gdb_assert (pe.pe_report_event == PTRACE_FORK);
 119           gdb_assert (pe.pe_other_pid == pid);
 120           if (find_inferior_pid (this, fpid) != nullptr)
 121             {
 122               ourstatus->value.related_pid = ptid_t (pe.pe_other_pid);
 123               wptid = ptid_t (fpid, pe.pe_tid, 0);
 124             }
 125
 126           obsd_enable_proc_events (ourstatus->value.related_pid.pid ());
 127           break;
 128         }
 129
 130       /* Ensure the ptid is updated with an LWP id on the first stop
 131          of a process.  */
 132       if (!in_thread_list (this, wptid))
 133         {
 134           if (in_thread_list (this, ptid_t (pid)))
 135             thread_change_ptid (this, ptid_t (pid), wptid);
 136           else
 137             add_thread (this, wptid);
 138         }
 139     }
 140   return wptid;
 141 }
 142
 143 void
 144 obsd_nat_target::post_attach (int pid)
 145 {
 146   obsd_enable_proc_events (pid);
 147 }
 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 }