GDB 6.1 (excluding .info files)

1 files changed, 520 insertions, 0 deletions

diff --git a/gnu/usr.bin/binutils/gdb/linux-nat.c b/gnu/usr.bin/binutils/gdb/linux-nat.c
new file mode 100644
index 00000000000..2680422cd50
--- /dev/null
+++ b/gnu/usr.bin/binutils/gdb/linux-nat.c
@@ -0,0 +1,520 @@
+/* GNU/Linux native-dependent code common to multiple platforms.
+   Copyright (C) 2003 Free Software Foundation, Inc.
+
+   This file is part of GDB.
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 2 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program; if not, write to the Free Software
+   Foundation, Inc., 59 Temple Place - Suite 330,
+   Boston, MA 02111-1307, USA.  */
+
+#include "defs.h"
+#include "inferior.h"
+#include "target.h"
+
+#include "gdb_wait.h"
+#include <sys/ptrace.h>
+
+#include "linux-nat.h"
+
+/* If the system headers did not provide the constants, hard-code the normal
+   values.  */
+#ifndef PTRACE_EVENT_FORK
+
+#define PTRACE_SETOPTIONS	0x4200
+#define PTRACE_GETEVENTMSG	0x4201
+
+/* options set using PTRACE_SETOPTIONS */
+#define PTRACE_O_TRACESYSGOOD	0x00000001
+#define PTRACE_O_TRACEFORK	0x00000002
+#define PTRACE_O_TRACEVFORK	0x00000004
+#define PTRACE_O_TRACECLONE	0x00000008
+#define PTRACE_O_TRACEEXEC	0x00000010
+#define PTRACE_O_TRACEVFORKDONE	0x00000020
+#define PTRACE_O_TRACEEXIT	0x00000040
+
+/* Wait extended result codes for the above trace options.  */
+#define PTRACE_EVENT_FORK	1
+#define PTRACE_EVENT_VFORK	2
+#define PTRACE_EVENT_CLONE	3
+#define PTRACE_EVENT_EXEC	4
+#define PTRACE_EVENT_VFORKDONE	5
+#define PTRACE_EVENT_EXIT	6
+
+#endif /* PTRACE_EVENT_FORK */
+
+/* We can't always assume that this flag is available, but all systems
+   with the ptrace event handlers also have __WALL, so it's safe to use
+   here.  */
+#ifndef __WALL
+#define __WALL          0x40000000 /* Wait for any child.  */
+#endif
+
+extern struct target_ops child_ops;
+
+static int linux_parent_pid;
+
+struct simple_pid_list
+{
+  int pid;
+  struct simple_pid_list *next;
+};
+struct simple_pid_list *stopped_pids;
+
+/* This variable is a tri-state flag: -1 for unknown, 0 if PTRACE_O_TRACEFORK
+   can not be used, 1 if it can.  */
+
+static int linux_supports_tracefork_flag = -1;
+
+/* If we have PTRACE_O_TRACEFORK, this flag indicates whether we also have
+   PTRACE_O_TRACEVFORKDONE.  */
+
+static int linux_supports_tracevforkdone_flag = -1;
+
+
+/* Trivial list manipulation functions to keep track of a list of
+   new stopped processes.  */
+static void
+add_to_pid_list (struct simple_pid_list **listp, int pid)
+{
+  struct simple_pid_list *new_pid = xmalloc (sizeof (struct simple_pid_list));
+  new_pid->pid = pid;
+  new_pid->next = *listp;
+  *listp = new_pid;
+}
+
+static int
+pull_pid_from_list (struct simple_pid_list **listp, int pid)
+{
+  struct simple_pid_list **p;
+
+  for (p = listp; *p != NULL; p = &(*p)->next)
+    if ((*p)->pid == pid)
+      {
+	struct simple_pid_list *next = (*p)->next;
+	xfree (*p);
+	*p = next;
+	return 1;
+      }
+  return 0;
+}
+
+void
+linux_record_stopped_pid (int pid)
+{
+  add_to_pid_list (&stopped_pids, pid);
+}
+
+
+/* A helper function for linux_test_for_tracefork, called after fork ().  */
+
+static void
+linux_tracefork_child (void)
+{
+  int ret;
+
+  ptrace (PTRACE_TRACEME, 0, 0, 0);
+  kill (getpid (), SIGSTOP);
+  fork ();
+  exit (0);
+}
+
+/* Determine if PTRACE_O_TRACEFORK can be used to follow fork events.  We
+   create a child process, attach to it, use PTRACE_SETOPTIONS to enable
+   fork tracing, and let it fork.  If the process exits, we assume that
+   we can't use TRACEFORK; if we get the fork notification, and we can
+   extract the new child's PID, then we assume that we can.  */
+
+static void
+linux_test_for_tracefork (void)
+{
+  int child_pid, ret, status;
+  long second_pid;
+
+  child_pid = fork ();
+  if (child_pid == -1)
+    perror_with_name ("linux_test_for_tracefork: fork");
+
+  if (child_pid == 0)
+    linux_tracefork_child ();
+
+  ret = waitpid (child_pid, &status, 0);
+  if (ret == -1)
+    perror_with_name ("linux_test_for_tracefork: waitpid");
+  else if (ret != child_pid)
+    error ("linux_test_for_tracefork: waitpid: unexpected result %d.", ret);
+  if (! WIFSTOPPED (status))
+    error ("linux_test_for_tracefork: waitpid: unexpected status %d.", status);
+
+  linux_supports_tracefork_flag = 0;
+
+  ret = ptrace (PTRACE_SETOPTIONS, child_pid, 0, PTRACE_O_TRACEFORK);
+  if (ret != 0)
+    {
+      ptrace (PTRACE_KILL, child_pid, 0, 0);
+      waitpid (child_pid, &status, 0);
+      return;
+    }
+
+  /* Check whether PTRACE_O_TRACEVFORKDONE is available.  */
+  ret = ptrace (PTRACE_SETOPTIONS, child_pid, 0,
+		PTRACE_O_TRACEFORK | PTRACE_O_TRACEVFORKDONE);
+  linux_supports_tracevforkdone_flag = (ret == 0);
+
+  ptrace (PTRACE_CONT, child_pid, 0, 0);
+  ret = waitpid (child_pid, &status, 0);
+  if (ret == child_pid && WIFSTOPPED (status)
+      && status >> 16 == PTRACE_EVENT_FORK)
+    {
+      second_pid = 0;
+      ret = ptrace (PTRACE_GETEVENTMSG, child_pid, 0, &second_pid);
+      if (ret == 0 && second_pid != 0)
+	{
+	  int second_status;
+
+	  linux_supports_tracefork_flag = 1;
+	  waitpid (second_pid, &second_status, 0);
+	  ptrace (PTRACE_DETACH, second_pid, 0, 0);
+	}
+    }
+
+  if (WIFSTOPPED (status))
+    {
+      ptrace (PTRACE_DETACH, child_pid, 0, 0);
+      waitpid (child_pid, &status, 0);
+    }
+}
+
+/* Return non-zero iff we have tracefork functionality available.
+   This function also sets linux_supports_tracefork_flag.  */
+
+static int
+linux_supports_tracefork (void)
+{
+  if (linux_supports_tracefork_flag == -1)
+    linux_test_for_tracefork ();
+  return linux_supports_tracefork_flag;
+}
+
+static int
+linux_supports_tracevforkdone (void)
+{
+  if (linux_supports_tracefork_flag == -1)
+    linux_test_for_tracefork ();
+  return linux_supports_tracevforkdone_flag;
+}
+
+
+void
+linux_enable_event_reporting (ptid_t ptid)
+{
+  int pid = ptid_get_pid (ptid);
+  int options;
+
+  if (! linux_supports_tracefork ())
+    return;
+
+  options = PTRACE_O_TRACEFORK | PTRACE_O_TRACEVFORK | PTRACE_O_TRACEEXEC;
+  if (linux_supports_tracevforkdone ())
+    options |= PTRACE_O_TRACEVFORKDONE;
+
+  /* Do not enable PTRACE_O_TRACEEXIT until GDB is more prepared to support
+     read-only process state.  */
+
+  ptrace (PTRACE_SETOPTIONS, pid, 0, options);
+}
+
+void
+child_post_attach (int pid)
+{
+  linux_enable_event_reporting (pid_to_ptid (pid));
+}
+
+void
+linux_child_post_startup_inferior (ptid_t ptid)
+{
+  linux_enable_event_reporting (ptid);
+}
+
+#ifndef LINUX_CHILD_POST_STARTUP_INFERIOR
+void
+child_post_startup_inferior (ptid_t ptid)
+{
+  linux_child_post_startup_inferior (ptid);
+}
+#endif
+
+int
+child_follow_fork (int follow_child)
+{
+  ptid_t last_ptid;
+  struct target_waitstatus last_status;
+  int has_vforked;
+  int parent_pid, child_pid;
+
+  get_last_target_status (&last_ptid, &last_status);
+  has_vforked = (last_status.kind == TARGET_WAITKIND_VFORKED);
+  parent_pid = ptid_get_pid (last_ptid);
+  child_pid = last_status.value.related_pid;
+
+  if (! follow_child)
+    {
+      /* We're already attached to the parent, by default. */
+
+      /* Before detaching from the child, remove all breakpoints from
+         it.  (This won't actually modify the breakpoint list, but will
+         physically remove the breakpoints from the child.) */
+      /* If we vforked this will remove the breakpoints from the parent
+	 also, but they'll be reinserted below.  */
+      detach_breakpoints (child_pid);
+
+      fprintf_filtered (gdb_stdout,
+			"Detaching after fork from child process %d.\n",
+			child_pid);
+
+      ptrace (PTRACE_DETACH, child_pid, 0, 0);
+
+      if (has_vforked)
+	{
+	  if (linux_supports_tracevforkdone ())
+	    {
+	      int status;
+
+	      ptrace (PTRACE_CONT, parent_pid, 0, 0);
+	      waitpid (parent_pid, &status, __WALL);
+	      if ((status >> 16) != PTRACE_EVENT_VFORKDONE)
+		warning ("Unexpected waitpid result %06x when waiting for "
+			 "vfork-done", status);
+	    }
+	  else
+	    {
+	      /* We can't insert breakpoints until the child has
+		 finished with the shared memory region.  We need to
+		 wait until that happens.  Ideal would be to just
+		 call:
+		 - ptrace (PTRACE_SYSCALL, parent_pid, 0, 0);
+		 - waitpid (parent_pid, &status, __WALL);
+		 However, most architectures can't handle a syscall
+		 being traced on the way out if it wasn't traced on
+		 the way in.
+
+		 We might also think to loop, continuing the child
+		 until it exits or gets a SIGTRAP.  One problem is
+		 that the child might call ptrace with PTRACE_TRACEME.
+
+		 There's no simple and reliable way to figure out when
+		 the vforked child will be done with its copy of the
+		 shared memory.  We could step it out of the syscall,
+		 two instructions, let it go, and then single-step the
+		 parent once.  When we have hardware single-step, this
+		 would work; with software single-step it could still
+		 be made to work but we'd have to be able to insert
+		 single-step breakpoints in the child, and we'd have
+		 to insert -just- the single-step breakpoint in the
+		 parent.  Very awkward.
+
+		 In the end, the best we can do is to make sure it
+		 runs for a little while.  Hopefully it will be out of
+		 range of any breakpoints we reinsert.  Usually this
+		 is only the single-step breakpoint at vfork's return
+		 point.  */
+
+	      usleep (10000);
+	    }
+
+	  /* Since we vforked, breakpoints were removed in the parent
+	     too.  Put them back.  */
+	  reattach_breakpoints (parent_pid);
+	}
+    }
+  else
+    {
+      char child_pid_spelling[40];
+
+      /* Needed to keep the breakpoint lists in sync.  */
+      if (! has_vforked)
+	detach_breakpoints (child_pid);
+
+      /* Before detaching from the parent, remove all breakpoints from it. */
+      remove_breakpoints ();
+
+      fprintf_filtered (gdb_stdout,
+			"Attaching after fork to child process %d.\n",
+			child_pid);
+
+      /* If we're vforking, we may want to hold on to the parent until
+	 the child exits or execs.  At exec time we can remove the old
+	 breakpoints from the parent and detach it; at exit time we
+	 could do the same (or even, sneakily, resume debugging it - the
+	 child's exec has failed, or something similar).
+
+	 This doesn't clean up "properly", because we can't call
+	 target_detach, but that's OK; if the current target is "child",
+	 then it doesn't need any further cleanups, and lin_lwp will
+	 generally not encounter vfork (vfork is defined to fork
+	 in libpthread.so).
+
+	 The holding part is very easy if we have VFORKDONE events;
+	 but keeping track of both processes is beyond GDB at the
+	 moment.  So we don't expose the parent to the rest of GDB.
+	 Instead we quietly hold onto it until such time as we can
+	 safely resume it.  */
+
+      if (has_vforked)
+	linux_parent_pid = parent_pid;
+      else
+	target_detach (NULL, 0);
+
+      inferior_ptid = pid_to_ptid (child_pid);
+      push_target (&child_ops);
+
+      /* Reset breakpoints in the child as appropriate.  */
+      follow_inferior_reset_breakpoints ();
+    }
+
+  return 0;
+}
+
+ptid_t
+linux_handle_extended_wait (int pid, int status,
+			    struct target_waitstatus *ourstatus)
+{
+  int event = status >> 16;
+
+  if (event == PTRACE_EVENT_CLONE)
+    internal_error (__FILE__, __LINE__,
+		    "unexpected clone event");
+
+  if (event == PTRACE_EVENT_FORK || event == PTRACE_EVENT_VFORK)
+    {
+      unsigned long new_pid;
+      int ret;
+
+      ptrace (PTRACE_GETEVENTMSG, pid, 0, &new_pid);
+
+      /* If we haven't already seen the new PID stop, wait for it now.  */
+      if (! pull_pid_from_list (&stopped_pids, new_pid))
+	{
+	  /* The new child has a pending SIGSTOP.  We can't affect it until it
+	     hits the SIGSTOP, but we're already attached.
+
+	     It won't be a clone (we didn't ask for clones in the event mask)
+	     so we can just call waitpid and wait for the SIGSTOP.  */
+	  do {
+	    ret = waitpid (new_pid, &status, 0);
+	  } while (ret == -1 && errno == EINTR);
+	  if (ret == -1)
+	    perror_with_name ("waiting for new child");
+	  else if (ret != new_pid)
+	    internal_error (__FILE__, __LINE__,
+			    "wait returned unexpected PID %d", ret);
+	  else if (!WIFSTOPPED (status) || WSTOPSIG (status) != SIGSTOP)
+	    internal_error (__FILE__, __LINE__,
+			    "wait returned unexpected status 0x%x", status);
+	}
+
+      ourstatus->kind = (event == PTRACE_EVENT_FORK)
+	? TARGET_WAITKIND_FORKED : TARGET_WAITKIND_VFORKED;
+      ourstatus->value.related_pid = new_pid;
+      return inferior_ptid;
+    }
+
+  if (event == PTRACE_EVENT_EXEC)
+    {
+      ourstatus->kind = TARGET_WAITKIND_EXECD;
+      ourstatus->value.execd_pathname
+	= xstrdup (child_pid_to_exec_file (pid));
+
+      if (linux_parent_pid)
+	{
+	  detach_breakpoints (linux_parent_pid);
+	  ptrace (PTRACE_DETACH, linux_parent_pid, 0, 0);
+
+	  linux_parent_pid = 0;
+	}
+
+      return inferior_ptid;
+    }
+
+  internal_error (__FILE__, __LINE__,
+		  "unknown ptrace event %d", event);
+}
+
+
+int
+child_insert_fork_catchpoint (int pid)
+{
+  if (! linux_supports_tracefork ())
+    error ("Your system does not support fork catchpoints.");
+
+  return 0;
+}
+
+int
+child_insert_vfork_catchpoint (int pid)
+{
+  if (!linux_supports_tracefork ())
+    error ("Your system does not support vfork catchpoints.");
+
+  return 0;
+}
+
+int
+child_insert_exec_catchpoint (int pid)
+{
+  if (!linux_supports_tracefork ())
+    error ("Your system does not support exec catchpoints.");
+
+  return 0;
+}
+
+void
+kill_inferior (void)
+{
+  int status;
+  int pid =  PIDGET (inferior_ptid);
+  struct target_waitstatus last;
+  ptid_t last_ptid;
+  int ret;
+
+  if (pid == 0)
+    return;
+
+  /* If we're stopped while forking and we haven't followed yet, kill the
+     other task.  We need to do this first because the parent will be
+     sleeping if this is a vfork.  */
+
+  get_last_target_status (&last_ptid, &last);
+
+  if (last.kind == TARGET_WAITKIND_FORKED
+      || last.kind == TARGET_WAITKIND_VFORKED)
+    {
+      ptrace (PT_KILL, last.value.related_pid);
+      ptrace_wait (null_ptid, &status);
+    }
+
+  /* Kill the current process.  */
+  ptrace (PT_KILL, pid, (PTRACE_ARG3_TYPE) 0, 0);
+  ret = ptrace_wait (null_ptid, &status);
+
+  /* We might get a SIGCHLD instead of an exit status.  This is
+     aggravated by the first kill above - a child has just died.  */
+
+  while (ret == pid && WIFSTOPPED (status))
+    {
+      ptrace (PT_KILL, pid, (PTRACE_ARG3_TYPE) 0, 0);
+      ret = ptrace_wait (null_ptid, &status);
+    }
+
+  target_mourn_inferior ();
+}