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-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 std::string
  39 obsd_nat_target::pid_to_str (ptid_t ptid)
  40 {
  41   if (ptid.lwp () != 0)
  42     return string_printf ("thread %ld", ptid.lwp ());
  43
  44   return normal_pid_to_str (ptid);
  45 }
  46
  47 void
  48 obsd_nat_target::update_thread_list ()
  49 {
  50   pid_t pid = inferior_ptid.pid ();
  51   struct ptrace_thread_state pts;
  52
  53   prune_threads ();
  54
  55   if (ptrace (PT_GET_THREAD_FIRST, pid, (caddr_t)&pts, sizeof pts) == -1)
  56     perror_with_name (("ptrace"));
  57
  58   while (pts.pts_tid != -1)
  59     {
  60       ptid_t ptid = ptid_t (pid, pts.pts_tid, 0);
  61
  62       if (!in_thread_list (this, ptid))
  63         {
  64           if (inferior_ptid.lwp () == 0)
  65             thread_change_ptid (this, inferior_ptid, ptid);
  66           else
  67             add_thread (this, ptid);
  68         }
  69
  70       if (ptrace (PT_GET_THREAD_NEXT, pid, (caddr_t)&pts, sizeof pts) == -1)
  71         perror_with_name (("ptrace"));
  72     }
  73 }
  74
  75 ptid_t
  76 obsd_nat_target::wait (ptid_t ptid, struct target_waitstatus *ourstatus,
  77                        target_wait_flags options)
  78 {
  79   pid_t pid;
  80   int status, save_errno;
  81
  82   do
  83     {
  84       set_sigint_trap ();
  85
  86       do
  87         {
  88           pid = waitpid (ptid.pid (), &status, 0);
  89           save_errno = errno;
  90         }
  91       while (pid == -1 && errno == EINTR);
  92
  93       clear_sigint_trap ();
  94
  95       if (pid == -1)
  96         {
  97           fprintf_unfiltered (gdb_stderr,
  98                               _("Child process unexpectedly missing: %s.\n"),
  99                               safe_strerror (save_errno));
 100
 101           /* Claim it exited with unknown signal.  */
 102           ourstatus->kind = TARGET_WAITKIND_SIGNALLED;
 103           ourstatus->value.sig = GDB_SIGNAL_UNKNOWN;
 104           return inferior_ptid;
 105         }
 106
 107       /* Ignore terminated detached child processes.  */
 108       if (!WIFSTOPPED (status) && pid != inferior_ptid.pid ())
 109         pid = -1;
 110     }
 111   while (pid == -1);
 112
 113   ptid = ptid_t (pid);
 114
 115   if (WIFSTOPPED (status))
 116     {
 117       ptrace_state_t pe;
 118       pid_t fpid;
 119
 120       if (ptrace (PT_GET_PROCESS_STATE, pid, (caddr_t)&pe, sizeof pe) == -1)
 121         perror_with_name (("ptrace"));
 122
 123       switch (pe.pe_report_event)
 124         {
 125         case PTRACE_FORK:
 126           ourstatus->kind = TARGET_WAITKIND_FORKED;
 127           ourstatus->value.related_pid = ptid_t (pe.pe_other_pid);
 128
 129           /* Make sure the other end of the fork is stopped too.  */
 130           fpid = waitpid (pe.pe_other_pid, &status, 0);
 131           if (fpid == -1)
 132             perror_with_name (("waitpid"));
 133
 134           if (ptrace (PT_GET_PROCESS_STATE, fpid,
 135                       (caddr_t)&pe, sizeof pe) == -1)
 136             perror_with_name (("ptrace"));
 137
 138           gdb_assert (pe.pe_report_event == PTRACE_FORK);
 139           gdb_assert (pe.pe_other_pid == pid);
 140           if (fpid == inferior_ptid.pid ())
 141             {
 142               ourstatus->value.related_pid = ptid_t (pe.pe_other_pid);
 143               return ptid_t (fpid);
 144             }
 145
 146           return ptid_t (pid);
 147         }
 148
 149       ptid = ptid_t (pid, pe.pe_tid, 0);
 150       if (!in_thread_list (this, ptid))
 151         {
 152           if (inferior_ptid.lwp () == 0)
 153             thread_change_ptid (this, inferior_ptid, ptid);
 154           else
 155             add_thread (this, ptid);
 156         }
 157     }
 158
 159   store_waitstatus (ourstatus, status);
 160   return ptid;
 161 }
 162
 163 #endif /* PT_GET_THREAD_FIRST */
 164
 165 #ifdef PT_GET_PROCESS_STATE
 166
 167 void
 168 obsd_nat_target::post_attach (int pid)
 169 {
 170   ptrace_event_t pe;
 171
 172   /* Set the initial event mask.  */
 173   memset (&pe, 0, sizeof pe);
 174   pe.pe_set_event |= PTRACE_FORK;
 175   if (ptrace (PT_SET_EVENT_MASK, pid,
 176               (PTRACE_TYPE_ARG3)&pe, sizeof pe) == -1)
 177     perror_with_name (("ptrace"));
 178 }
 179
 180 void
 181 obsd_nat_target::post_startup_inferior (ptid_t pid)
 182 {
 183   ptrace_event_t pe;
 184
 185   /* Set the initial event mask.  */
 186   memset (&pe, 0, sizeof pe);
 187   pe.pe_set_event |= PTRACE_FORK;
 188   if (ptrace (PT_SET_EVENT_MASK, pid.pid (),
 189               (PTRACE_TYPE_ARG3)&pe, sizeof pe) == -1)
 190     perror_with_name (("ptrace"));
 191 }
 192
 193 /* Target hook for follow_fork.  On entry and at return inferior_ptid is
 194    the ptid of the followed inferior.  */
 195
 196 void
 197 obsd_nat_target::follow_fork (bool follow_child, bool detach_fork)
 198 {
 199   if (!follow_child)
 200     {
 201       struct thread_info *tp = inferior_thread ();
 202       pid_t child_pid = tp->pending_follow.value.related_pid.pid ();
 203
 204       /* Breakpoints have already been detached from the child by
 205          infrun.c.  */
 206
 207       if (ptrace (PT_DETACH, child_pid, (PTRACE_TYPE_ARG3)1, 0) == -1)
 208         perror_with_name (("ptrace"));
 209     }
 210 }
 211
 212 int
 213 obsd_nat_target::insert_fork_catchpoint (int pid)
 214 {
 215   return 0;
 216 }
 217
 218 int
 219 obsd_nat_target::remove_fork_catchpoint (int pid)
 220 {
 221   return 0;
 222 }
 223
 224 #endif /* PT_GET_PROCESS_STATE */