gdb/obsd-nat.c

   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 */