gdb/obsd-nat.c

   1 /* Native-dependent code for OpenBSD.
   2
   3    Copyright (C) 2012-2014 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 "gdb_assert.h"
  26 #include <sys/types.h>
  27 #include <sys/ptrace.h>
  28 #include <sys/wait.h>
  29
  30 #include "inf-child.h"
  31 #include "obsd-nat.h"
  32
  33 /* OpenBSD 5.2 and later include rthreads which uses a thread model
  34    that maps userland threads directly onto kernel threads in a 1:1
  35    fashion.  */
  36
  37 #ifdef PT_GET_THREAD_FIRST
  38
  39 static char *
  40 obsd_pid_to_str (struct target_ops *ops, ptid_t ptid)
  41 {
  42   if (ptid_get_lwp (ptid) != 0)
  43     {
  44       static char buf[64];
  45
  46       xsnprintf (buf, sizeof buf, "thread %ld", ptid_get_lwp (ptid));
  47       return buf;
  48     }
  49
  50   return normal_pid_to_str (ptid);
  51 }
  52
  53 static void
  54 obsd_find_new_threads (struct target_ops *ops)
  55 {
  56   pid_t pid = ptid_get_pid (inferior_ptid);
  57   struct ptrace_thread_state pts;
  58
  59   if (ptrace (PT_GET_THREAD_FIRST, pid, (caddr_t)&pts, sizeof pts) == -1)
  60     perror_with_name (("ptrace"));
  61
  62   while (pts.pts_tid != -1)
  63     {
  64       ptid_t ptid = ptid_build (pid, pts.pts_tid, 0);
  65
  66       if (!in_thread_list (ptid))
  67         {
  68           if (ptid_get_lwp (inferior_ptid) == 0)
  69             thread_change_ptid (inferior_ptid, ptid);
  70           else
  71             add_thread (ptid);
  72         }
  73
  74       if (ptrace (PT_GET_THREAD_NEXT, pid, (caddr_t)&pts, sizeof pts) == -1)
  75         perror_with_name (("ptrace"));
  76     }
  77 }
  78
  79 static ptid_t
  80 obsd_wait (struct target_ops *ops,
  81            ptid_t ptid, struct target_waitstatus *ourstatus, int options)
  82 {
  83   pid_t pid;
  84   int status, save_errno;
  85
  86   do
  87     {
  88       set_sigint_trap ();
  89
  90       do
  91         {
  92           pid = waitpid (ptid_get_pid (ptid), &status, 0);
  93           save_errno = errno;
  94         }
  95       while (pid == -1 && errno == EINTR);
  96
  97       clear_sigint_trap ();
  98
  99       if (pid == -1)
 100         {
 101           fprintf_unfiltered (gdb_stderr,
 102                               _("Child process unexpectedly missing: %s.\n"),
 103                               safe_strerror (save_errno));
 104
 105           /* Claim it exited with unknown signal.  */
 106           ourstatus->kind = TARGET_WAITKIND_SIGNALLED;
 107           ourstatus->value.sig = GDB_SIGNAL_UNKNOWN;
 108           return inferior_ptid;
 109         }
 110
 111       /* Ignore terminated detached child processes.  */
 112       if (!WIFSTOPPED (status) && pid != ptid_get_pid (inferior_ptid))
 113         pid = -1;
 114     }
 115   while (pid == -1);
 116
 117   ptid = pid_to_ptid (pid);
 118
 119   if (WIFSTOPPED (status))
 120     {
 121       ptrace_state_t pe;
 122       pid_t fpid;
 123
 124       if (ptrace (PT_GET_PROCESS_STATE, pid, (caddr_t)&pe, sizeof pe) == -1)
 125         perror_with_name (("ptrace"));
 126
 127       switch (pe.pe_report_event)
 128         {
 129         case PTRACE_FORK:
 130           ourstatus->kind = TARGET_WAITKIND_FORKED;
 131           ourstatus->value.related_pid = pid_to_ptid (pe.pe_other_pid);
 132
 133           /* Make sure the other end of the fork is stopped too.  */
 134           fpid = waitpid (pe.pe_other_pid, &status, 0);
 135           if (fpid == -1)
 136             perror_with_name (("waitpid"));
 137
 138           if (ptrace (PT_GET_PROCESS_STATE, fpid,
 139                       (caddr_t)&pe, sizeof pe) == -1)
 140             perror_with_name (("ptrace"));
 141
 142           gdb_assert (pe.pe_report_event == PTRACE_FORK);
 143           gdb_assert (pe.pe_other_pid == pid);
 144           if (fpid == ptid_get_pid (inferior_ptid))
 145             {
 146               ourstatus->value.related_pid = pid_to_ptid (pe.pe_other_pid);
 147               return pid_to_ptid (fpid);
 148             }
 149
 150           return pid_to_ptid (pid);
 151         }
 152
 153       ptid = ptid_build (pid, pe.pe_tid, 0);
 154       if (!in_thread_list (ptid))
 155         {
 156           if (ptid_get_lwp (inferior_ptid) == 0)
 157             thread_change_ptid (inferior_ptid, ptid);
 158           else
 159             add_thread (ptid);
 160         }
 161     }
 162
 163   store_waitstatus (ourstatus, status);
 164   return ptid;
 165 }
 166
 167 void
 168 obsd_add_target (struct target_ops *t)
 169 {
 170   /* Override some methods to support threads.  */
 171   t->to_pid_to_str = obsd_pid_to_str;
 172   t->to_find_new_threads = obsd_find_new_threads;
 173   t->to_wait = obsd_wait;
 174   add_target (t);
 175 }
 176
 177 #else
 178
 179 void
 180 obsd_add_target (struct target_ops *t)
 181 {
 182   add_target (t);
 183 }
 184
 185 #endif /* PT_GET_THREAD_FIRST */