Move shared native target specific code to gdb/nat

https://sourceware.org/gdb/wiki/Common describes the following
directory structure:

 gdb/nat/
   Native target backend files. Code that interfaces with the
   host debug API. E.g., ptrace code, Windows debug API code,
   procfs code should go here.

 gdb/target/
   Host-independent, target vector specific code (target_ops).

 gdb/common/
   All other shared code.

This commit moves all native target backend files currently in
gdb/common to gdb/nat.

gdb/
2014-06-20  Gary Benson  <gbenson@redhat.com>

	* common/gdb_thread_db.h: Moved to nat.  All includes updated.
	* common/glibc_thread_db.h: Likewise.
	* common/i386-cpuid.h: Likewise.
	* common/i386-gcc-cpuid.h: Likewise.
	* common/linux-btrace.h: Likewise.
	* common/linux-osdata.h: Likewise.
	* common/linux-procfs.h: Likewise.
	* common/linux-ptrace.h: Likewise.
	* common/mips-linux-watch.h: Likewise.
	* common/linux-btrace.c: Moved to nat.
	* common/linux-osdata.c: Likewise.
	* common/linux-procfs.c: Likewise.
	* common/linux-ptrace.c: Likewise.
	* common/mips-linux-watch.c: Likewise.
	* nat/gdb_thread_db.h: Moved from common.
	* nat/glibc_thread_db.h: Likewise.
	* nat/i386-cpuid.h: Likewise.
	* nat/i386-gcc-cpuid.h: Likewise.
	* nat/linux-btrace.c: Likewise.
	* nat/linux-btrace.h: Likewise.
	* nat/linux-osdata.c: Likewise.
	* nat/linux-osdata.h: Likewise.
	* nat/linux-procfs.c: Likewise.
	* nat/linux-procfs.h: Likewise.
	* nat/linux-ptrace.c: Likewise.
	* nat/linux-ptrace.h: Likewise.
	* nat/mips-linux-watch.c: Likewise.
	* nat/mips-linux-watch.h: Likewise.
	* Makefile.in (HFILES_NO_SRCDIR): Reflect new locations.
	(object file files): Reordered.
	* gdb/copyright.py (EXCLUDE_LIST): Reflect new location
	of glibc_thread_db.h.

gdb/gdbserver/
2014-06-20  Gary Benson  <gbenson@redhat.com>

	* Makefile.in (SFILES): Update locations for files moved
	from common to nat.
	(object file files): Reordered.

gdb/testsuite/
2014-06-20  Gary Benson  <gbenson@redhat.com>

	* gdb.arch/i386-avx.exp: Fix include file location.
	* gdb.arch/i386-sse.exp: Likewise.

1 files changed, 553 insertions, 0 deletions

diff --git a/gdb/nat/linux-ptrace.c b/gdb/nat/linux-ptrace.c
new file mode 100644
index 0000000..3ad2113
--- /dev/null
+++ b/gdb/nat/linux-ptrace.c
@@ -0,0 +1,553 @@
+/* Linux-specific ptrace manipulation routines.
+   Copyright (C) 2012-2014 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 3 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, see <http://www.gnu.org/licenses/>.  */
+
+#ifdef GDBSERVER
+#include "server.h"
+#else
+#include "defs.h"
+#include <string.h>
+#endif
+
+#include "linux-ptrace.h"
+#include "linux-procfs.h"
+#include "linux-waitpid.h"
+#include "buffer.h"
+#include "gdb_assert.h"
+#include "gdb_wait.h"
+
+#include <stdint.h>
+
+/* Stores the currently supported ptrace options.  A value of
+   -1 means we did not check for features yet.  A value of 0 means
+   there are no supported features.  */
+static int current_ptrace_options = -1;
+
+/* Find all possible reasons we could fail to attach PID and append
+   these as strings to the already initialized BUFFER.  '\0'
+   termination of BUFFER must be done by the caller.  */
+
+void
+linux_ptrace_attach_fail_reason (pid_t pid, struct buffer *buffer)
+{
+  pid_t tracerpid;
+
+  tracerpid = linux_proc_get_tracerpid (pid);
+  if (tracerpid > 0)
+    buffer_xml_printf (buffer, _("process %d is already traced "
+				 "by process %d"),
+		       (int) pid, (int) tracerpid);
+
+  if (linux_proc_pid_is_zombie (pid))
+    buffer_xml_printf (buffer, _("process %d is a zombie "
+				 "- the process has already terminated"),
+		       (int) pid);
+}
+
+#if defined __i386__ || defined __x86_64__
+
+/* Address of the 'ret' instruction in asm code block below.  */
+extern void (linux_ptrace_test_ret_to_nx_instr) (void);
+
+#include <sys/reg.h>
+#include <sys/mman.h>
+#include <signal.h>
+
+#endif /* defined __i386__ || defined __x86_64__ */
+
+/* Test broken off-trunk Linux kernel patchset for NX support on i386.  It was
+   removed in Fedora kernel 88fa1f0332d188795ed73d7ac2b1564e11a0b4cd.
+
+   Test also x86_64 arch for PaX support.  */
+
+static void
+linux_ptrace_test_ret_to_nx (void)
+{
+#if defined __i386__ || defined __x86_64__
+  pid_t child, got_pid;
+  gdb_byte *return_address, *pc;
+  long l;
+  int status, kill_status;
+
+  return_address = mmap (NULL, 2, PROT_READ | PROT_WRITE,
+			 MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
+  if (return_address == MAP_FAILED)
+    {
+      warning (_("linux_ptrace_test_ret_to_nx: Cannot mmap: %s"),
+	       strerror (errno));
+      return;
+    }
+
+  /* Put there 'int3'.  */
+  *return_address = 0xcc;
+
+  child = fork ();
+  switch (child)
+    {
+    case -1:
+      warning (_("linux_ptrace_test_ret_to_nx: Cannot fork: %s"),
+	       strerror (errno));
+      return;
+
+    case 0:
+      l = ptrace (PTRACE_TRACEME, 0, (PTRACE_TYPE_ARG3) NULL,
+		  (PTRACE_TYPE_ARG4) NULL);
+      if (l != 0)
+	warning (_("linux_ptrace_test_ret_to_nx: Cannot PTRACE_TRACEME: %s"),
+		 strerror (errno));
+      else
+	{
+#if defined __i386__
+	  asm volatile ("pushl %0;"
+			".globl linux_ptrace_test_ret_to_nx_instr;"
+			"linux_ptrace_test_ret_to_nx_instr:"
+			"ret"
+			: : "r" (return_address) : "%esp", "memory");
+#elif defined __x86_64__
+	  asm volatile ("pushq %0;"
+			".globl linux_ptrace_test_ret_to_nx_instr;"
+			"linux_ptrace_test_ret_to_nx_instr:"
+			"ret"
+			: : "r" ((uint64_t) (uintptr_t) return_address)
+			: "%rsp", "memory");
+#else
+# error "!__i386__ && !__x86_64__"
+#endif
+	  gdb_assert_not_reached ("asm block did not terminate");
+	}
+
+      _exit (1);
+    }
+
+  errno = 0;
+  got_pid = waitpid (child, &status, 0);
+  if (got_pid != child)
+    {
+      warning (_("linux_ptrace_test_ret_to_nx: waitpid returned %ld: %s"),
+	       (long) got_pid, strerror (errno));
+      return;
+    }
+
+  if (WIFSIGNALED (status))
+    {
+      if (WTERMSIG (status) != SIGKILL)
+	warning (_("linux_ptrace_test_ret_to_nx: WTERMSIG %d is not SIGKILL!"),
+		 (int) WTERMSIG (status));
+      else
+	warning (_("Cannot call inferior functions, Linux kernel PaX "
+		   "protection forbids return to non-executable pages!"));
+      return;
+    }
+
+  if (!WIFSTOPPED (status))
+    {
+      warning (_("linux_ptrace_test_ret_to_nx: status %d is not WIFSTOPPED!"),
+	       status);
+      return;
+    }
+
+  /* We may get SIGSEGV due to missing PROT_EXEC of the return_address.  */
+  if (WSTOPSIG (status) != SIGTRAP && WSTOPSIG (status) != SIGSEGV)
+    {
+      warning (_("linux_ptrace_test_ret_to_nx: "
+		 "WSTOPSIG %d is neither SIGTRAP nor SIGSEGV!"),
+	       (int) WSTOPSIG (status));
+      return;
+    }
+
+  errno = 0;
+#if defined __i386__
+  l = ptrace (PTRACE_PEEKUSER, child, (PTRACE_TYPE_ARG3) (uintptr_t) (EIP * 4),
+	      (PTRACE_TYPE_ARG4) NULL);
+#elif defined __x86_64__
+  l = ptrace (PTRACE_PEEKUSER, child, (PTRACE_TYPE_ARG3) (uintptr_t) (RIP * 8),
+	      (PTRACE_TYPE_ARG4) NULL);
+#else
+# error "!__i386__ && !__x86_64__"
+#endif
+  if (errno != 0)
+    {
+      warning (_("linux_ptrace_test_ret_to_nx: Cannot PTRACE_PEEKUSER: %s"),
+	       strerror (errno));
+      return;
+    }
+  pc = (void *) (uintptr_t) l;
+
+  kill (child, SIGKILL);
+  ptrace (PTRACE_KILL, child, (PTRACE_TYPE_ARG3) NULL,
+	  (PTRACE_TYPE_ARG4) NULL);
+
+  errno = 0;
+  got_pid = waitpid (child, &kill_status, 0);
+  if (got_pid != child)
+    {
+      warning (_("linux_ptrace_test_ret_to_nx: "
+		 "PTRACE_KILL waitpid returned %ld: %s"),
+	       (long) got_pid, strerror (errno));
+      return;
+    }
+  if (!WIFSIGNALED (kill_status))
+    {
+      warning (_("linux_ptrace_test_ret_to_nx: "
+		 "PTRACE_KILL status %d is not WIFSIGNALED!"),
+	       status);
+      return;
+    }
+
+  /* + 1 is there as x86* stops after the 'int3' instruction.  */
+  if (WSTOPSIG (status) == SIGTRAP && pc == return_address + 1)
+    {
+      /* PASS */
+      return;
+    }
+
+  /* We may get SIGSEGV due to missing PROT_EXEC of the RETURN_ADDRESS page.  */
+  if (WSTOPSIG (status) == SIGSEGV && pc == return_address)
+    {
+      /* PASS */
+      return;
+    }
+
+  if ((void (*) (void)) pc != &linux_ptrace_test_ret_to_nx_instr)
+    warning (_("linux_ptrace_test_ret_to_nx: PC %p is neither near return "
+	       "address %p nor is the return instruction %p!"),
+	     pc, return_address, &linux_ptrace_test_ret_to_nx_instr);
+  else
+    warning (_("Cannot call inferior functions on this system - "
+	       "Linux kernel with broken i386 NX (non-executable pages) "
+	       "support detected!"));
+#endif /* defined __i386__ || defined __x86_64__ */
+}
+
+/* Helper function to fork a process and make the child process call
+   the function FUNCTION, passing CHILD_STACK as parameter.
+
+   For MMU-less targets, clone is used instead of fork, and
+   CHILD_STACK is used as stack space for the cloned child.  If NULL,
+   stack space is allocated via malloc (and subsequently passed to
+   FUNCTION).  For MMU targets, CHILD_STACK is ignored.  */
+
+static int
+linux_fork_to_function (gdb_byte *child_stack, void (*function) (gdb_byte *))
+{
+  int child_pid;
+
+  /* Sanity check the function pointer.  */
+  gdb_assert (function != NULL);
+
+#if defined(__UCLIBC__) && defined(HAS_NOMMU)
+#define STACK_SIZE 4096
+
+    if (child_stack == NULL)
+      child_stack = xmalloc (STACK_SIZE * 4);
+
+    /* Use CLONE_VM instead of fork, to support uClinux (no MMU).  */
+#ifdef __ia64__
+      child_pid = __clone2 (function, child_stack, STACK_SIZE,
+			    CLONE_VM | SIGCHLD, child_stack + STACK_SIZE * 2);
+#else /* !__ia64__ */
+      child_pid = clone (function, child_stack + STACK_SIZE,
+			 CLONE_VM | SIGCHLD, child_stack + STACK_SIZE * 2);
+#endif /* !__ia64__ */
+#else /* !defined(__UCLIBC) && defined(HAS_NOMMU) */
+  child_pid = fork ();
+
+  if (child_pid == 0)
+    function (NULL);
+#endif /* defined(__UCLIBC) && defined(HAS_NOMMU) */
+
+  if (child_pid == -1)
+    perror_with_name (("fork"));
+
+  return child_pid;
+}
+
+/* A helper function for linux_check_ptrace_features, called after
+   the child forks a grandchild.  */
+
+static void
+linux_grandchild_function (gdb_byte *child_stack)
+{
+  /* Free any allocated stack.  */
+  xfree (child_stack);
+
+  /* This code is only reacheable by the grandchild (child's child)
+     process.  */
+  _exit (0);
+}
+
+/* A helper function for linux_check_ptrace_features, called after
+   the parent process forks a child.  The child allows itself to
+   be traced by its parent.  */
+
+static void
+linux_child_function (gdb_byte *child_stack)
+{
+  ptrace (PTRACE_TRACEME, 0, (PTRACE_TYPE_ARG3) 0, (PTRACE_TYPE_ARG4) 0);
+  kill (getpid (), SIGSTOP);
+
+  /* Fork a grandchild.  */
+  linux_fork_to_function (child_stack, linux_grandchild_function);
+
+  /* This code is only reacheable by the child (grandchild's parent)
+     process.  */
+  _exit (0);
+}
+
+static void linux_test_for_tracesysgood (int child_pid);
+static void linux_test_for_tracefork (int child_pid);
+
+/* Determine ptrace features available on this target.  */
+
+static void
+linux_check_ptrace_features (void)
+{
+  int child_pid, ret, status;
+
+  /* Initialize the options.  */
+  current_ptrace_options = 0;
+
+  /* Fork a child so we can do some testing.  The child will call
+     linux_child_function and will get traced.  The child will
+     eventually fork a grandchild so we can test fork event
+     reporting.  */
+  child_pid = linux_fork_to_function (NULL, linux_child_function);
+
+  ret = my_waitpid (child_pid, &status, 0);
+  if (ret == -1)
+    perror_with_name (("waitpid"));
+  else if (ret != child_pid)
+    error (_("linux_check_ptrace_features: waitpid: unexpected result %d."),
+	   ret);
+  if (! WIFSTOPPED (status))
+    error (_("linux_check_ptrace_features: waitpid: unexpected status %d."),
+	   status);
+
+  linux_test_for_tracesysgood (child_pid);
+
+  linux_test_for_tracefork (child_pid);
+
+  /* Clean things up and kill any pending children.  */
+  do
+    {
+      ret = ptrace (PTRACE_KILL, child_pid, (PTRACE_TYPE_ARG3) 0,
+		    (PTRACE_TYPE_ARG4) 0);
+      if (ret != 0)
+	warning (_("linux_check_ptrace_features: failed to kill child"));
+      my_waitpid (child_pid, &status, 0);
+    }
+  while (WIFSTOPPED (status));
+}
+
+/* Determine if PTRACE_O_TRACESYSGOOD can be used to catch
+   syscalls.  */
+
+static void
+linux_test_for_tracesysgood (int child_pid)
+{
+#ifdef GDBSERVER
+  /* gdbserver does not support PTRACE_O_TRACESYSGOOD.  */
+#else
+  int ret;
+
+  ret = ptrace (PTRACE_SETOPTIONS, child_pid, (PTRACE_TYPE_ARG3) 0,
+		(PTRACE_TYPE_ARG4) PTRACE_O_TRACESYSGOOD);
+  if (ret == 0)
+    current_ptrace_options |= PTRACE_O_TRACESYSGOOD;
+#endif
+}
+
+/* Determine if PTRACE_O_TRACEFORK can be used to follow fork
+   events.  */
+
+static void
+linux_test_for_tracefork (int child_pid)
+{
+  int ret, status;
+  long second_pid;
+
+  /* First, set the PTRACE_O_TRACEFORK option.  If this fails, we
+     know for sure that it is not supported.  */
+  ret = ptrace (PTRACE_SETOPTIONS, child_pid, (PTRACE_TYPE_ARG3) 0,
+		(PTRACE_TYPE_ARG4) PTRACE_O_TRACEFORK);
+
+  if (ret != 0)
+    return;
+
+#ifdef GDBSERVER
+  /* gdbserver does not support PTRACE_O_TRACEVFORKDONE yet.  */
+#else
+  /* Check if the target supports PTRACE_O_TRACEVFORKDONE.  */
+  ret = ptrace (PTRACE_SETOPTIONS, child_pid, (PTRACE_TYPE_ARG3) 0,
+		(PTRACE_TYPE_ARG4) (PTRACE_O_TRACEFORK
+				    | PTRACE_O_TRACEVFORKDONE));
+  if (ret == 0)
+    current_ptrace_options |= PTRACE_O_TRACEVFORKDONE;
+#endif
+
+  /* Setting PTRACE_O_TRACEFORK did not cause an error, however we
+     don't know for sure that the feature is available; old
+     versions of PTRACE_SETOPTIONS ignored unknown options.
+     Therefore, we attach to the child process, use PTRACE_SETOPTIONS
+     to enable fork tracing, and let it fork.  If the process exits,
+     we assume that we can't use PTRACE_O_TRACEFORK; if we get the
+     fork notification, and we can extract the new child's PID, then
+     we assume that we can.
+
+     We do not explicitly check for vfork tracing here.  It is
+     assumed that vfork tracing is available whenever fork tracing
+     is available.  */
+  ret = ptrace (PTRACE_CONT, child_pid, (PTRACE_TYPE_ARG3) 0,
+		(PTRACE_TYPE_ARG4) 0);
+  if (ret != 0)
+    warning (_("linux_test_for_tracefork: failed to resume child"));
+
+  ret = my_waitpid (child_pid, &status, 0);
+
+  /* Check if we received a fork event notification.  */
+  if (ret == child_pid && WIFSTOPPED (status)
+      && status >> 16 == PTRACE_EVENT_FORK)
+    {
+      /* We did receive a fork event notification.  Make sure its PID
+	 is reported.  */
+      second_pid = 0;
+      ret = ptrace (PTRACE_GETEVENTMSG, child_pid, (PTRACE_TYPE_ARG3) 0,
+		    (PTRACE_TYPE_ARG4) &second_pid);
+      if (ret == 0 && second_pid != 0)
+	{
+	  int second_status;
+
+	  /* We got the PID from the grandchild, which means fork
+	     tracing is supported.  */
+#ifdef GDBSERVER
+	  /* Do not enable all the options for now since gdbserver does not
+	     properly support them.  This restriction will be lifted when
+	     gdbserver is augmented to support them.  */
+	  current_ptrace_options |= PTRACE_O_TRACECLONE;
+#else
+	  current_ptrace_options |= PTRACE_O_TRACEFORK | PTRACE_O_TRACEVFORK
+	    | PTRACE_O_TRACECLONE | PTRACE_O_TRACEEXEC;
+
+	  /* Do not enable PTRACE_O_TRACEEXIT until GDB is more prepared to
+	     support read-only process state.  */
+#endif
+
+	  /* Do some cleanup and kill the grandchild.  */
+	  my_waitpid (second_pid, &second_status, 0);
+	  ret = ptrace (PTRACE_KILL, second_pid, (PTRACE_TYPE_ARG3) 0,
+			(PTRACE_TYPE_ARG4) 0);
+	  if (ret != 0)
+	    warning (_("linux_test_for_tracefork: "
+		       "failed to kill second child"));
+	  my_waitpid (second_pid, &status, 0);
+	}
+    }
+  else
+    warning (_("linux_test_for_tracefork: unexpected result from waitpid "
+	     "(%d, status 0x%x)"), ret, status);
+}
+
+/* Enable reporting of all currently supported ptrace events.  */
+
+void
+linux_enable_event_reporting (pid_t pid)
+{
+  /* Check if we have initialized the ptrace features for this
+     target.  If not, do it now.  */
+  if (current_ptrace_options == -1)
+    linux_check_ptrace_features ();
+
+  /* Set the options.  */
+  ptrace (PTRACE_SETOPTIONS, pid, (PTRACE_TYPE_ARG3) 0,
+	  (PTRACE_TYPE_ARG4) (uintptr_t) current_ptrace_options);
+}
+
+/* Disable reporting of all currently supported ptrace events.  */
+
+void
+linux_disable_event_reporting (pid_t pid)
+{
+  /* Set the options.  */
+  ptrace (PTRACE_SETOPTIONS, pid, (PTRACE_TYPE_ARG3) 0, 0);
+}
+
+/* Returns non-zero if PTRACE_OPTIONS is contained within
+   CURRENT_PTRACE_OPTIONS, therefore supported.  Returns 0
+   otherwise.  */
+
+static int
+ptrace_supports_feature (int ptrace_options)
+{
+  gdb_assert (current_ptrace_options >= 0);
+
+  return ((current_ptrace_options & ptrace_options) == ptrace_options);
+}
+
+/* Returns non-zero if PTRACE_EVENT_FORK is supported by ptrace,
+   0 otherwise.  Note that if PTRACE_EVENT_FORK is supported so is
+   PTRACE_EVENT_CLONE, PTRACE_EVENT_EXEC and PTRACE_EVENT_VFORK,
+   since they were all added to the kernel at the same time.  */
+
+int
+linux_supports_tracefork (void)
+{
+  return ptrace_supports_feature (PTRACE_O_TRACEFORK);
+}
+
+/* Returns non-zero if PTRACE_EVENT_CLONE is supported by ptrace,
+   0 otherwise.  Note that if PTRACE_EVENT_CLONE is supported so is
+   PTRACE_EVENT_FORK, PTRACE_EVENT_EXEC and PTRACE_EVENT_VFORK,
+   since they were all added to the kernel at the same time.  */
+
+int
+linux_supports_traceclone (void)
+{
+  return ptrace_supports_feature (PTRACE_O_TRACECLONE);
+}
+
+/* Returns non-zero if PTRACE_O_TRACEVFORKDONE is supported by
+   ptrace, 0 otherwise.  */
+
+int
+linux_supports_tracevforkdone (void)
+{
+  return ptrace_supports_feature (PTRACE_O_TRACEVFORKDONE);
+}
+
+/* Returns non-zero if PTRACE_O_TRACESYSGOOD is supported by ptrace,
+   0 otherwise.  */
+
+int
+linux_supports_tracesysgood (void)
+{
+  return ptrace_supports_feature (PTRACE_O_TRACESYSGOOD);
+}
+
+/* Display possible problems on this system.  Display them only once per GDB
+   execution.  */
+
+void
+linux_ptrace_init_warnings (void)
+{
+  static int warned = 0;
+
+  if (warned)
+    return;
+  warned = 1;
+
+  linux_ptrace_test_ret_to_nx ();
+}