gdb/

Support Valgrind attachments broken by the PIE support.
	* auxv.c: Include gdbcore.h.
	(procfs_xfer_auxv): Make static.  Reduce its comment.  Drop its
	parameters ops, object and annex.  Remove their assertions.
	(ld_so_xfer_auxv, memory_xfer_auxv): New function.
	* auxv.h (procfs_xfer_auxv): Remove comment.  Rename to ...
	(memory_xfer_auxv): ... here.
	* linux-nat.c (linux_xfer_partial): Rename procfs_xfer_auxv to
	memory_xfer_auxv.
	* procfs.c (procfs_xfer_partial): Likewise.
	* solib-svr4.c (svr4_relocate_main_executable): New prototype.
	(svr4_special_symbol_handling): Call svr4_relocate_main_executable.
	(svr4_solib_create_inferior_hook): Conditionalize the
	svr4_relocate_main_executable call.

gdb/testsuite/
	* gdb.base/valgrind-db-attach.exp, gdb.base/valgrind-db-attach.c: New.

gdb/ChangeLog

@@ -1,3 +1,20 @@
+2010-01-14  Jan Kratochvil  <jan.kratochvil@redhat.com>
+
+	Support Valgrind attachments broken by the PIE support.
+	* auxv.c: Include gdbcore.h.
+	(procfs_xfer_auxv): Make static.  Reduce its comment.  Drop its
+	parameters ops, object and annex.  Remove their assertions.
+	(ld_so_xfer_auxv, memory_xfer_auxv): New function.
+	* auxv.h (procfs_xfer_auxv): Remove comment.  Rename to ...
+	(memory_xfer_auxv): ... here.
+	* linux-nat.c (linux_xfer_partial): Rename procfs_xfer_auxv to
+	memory_xfer_auxv.
+	* procfs.c (procfs_xfer_partial): Likewise.
+	* solib-svr4.c (svr4_relocate_main_executable): New prototype.
+	(svr4_special_symbol_handling): Call svr4_relocate_main_executable.
+	(svr4_solib_create_inferior_hook): Conditionalize the
+	svr4_relocate_main_executable call.
+
 2010-01-14  Jan Kratochvil  <jan.kratochvil@redhat.com>
 
 	* solib-svr4.c (scan_dyntag): Remove variable dyn_addr.  New variable

gdb/auxv.c

@@ -25,6 +25,7 @@
 #include "inferior.h"
 #include "valprint.h"
 #include "gdb_assert.h"
+#include "gdbcore.h"
 
 #include "auxv.h"
 #include "elf/common.h"
@@ -33,15 +34,11 @@
 #include <fcntl.h>
 
 
-/* This function is called like a to_xfer_partial hook, but must be
+/* This function handles access via /proc/PID/auxv, which is a common method
-   called with TARGET_OBJECT_AUXV.  It handles access via
+   for native targets.  */
-   /proc/PID/auxv, which is a common method for native targets.  */
 
-LONGEST
+static LONGEST
-procfs_xfer_auxv (struct target_ops *ops,
+procfs_xfer_auxv (gdb_byte *readbuf,
-		  enum target_object object,
-		  const char *annex,
-		  gdb_byte *readbuf,
 		  const gdb_byte *writebuf,
 		  ULONGEST offset,
 		  LONGEST len)
@@ -50,9 +47,6 @@ procfs_xfer_auxv (struct target_ops *ops,
   int fd;
   LONGEST n;
 
-  gdb_assert (object == TARGET_OBJECT_AUXV);
-  gdb_assert (readbuf || writebuf);
-
   pathname = xstrprintf ("/proc/%d/auxv", PIDGET (inferior_ptid));
   fd = open (pathname, writebuf != NULL ? O_WRONLY : O_RDONLY);
   xfree (pathname);
@@ -72,6 +66,143 @@ procfs_xfer_auxv (struct target_ops *ops,
   return n;
 }
 
+/* This function handles access via ld.so's symbol `_dl_auxv'.  */
+
+static LONGEST
+ld_so_xfer_auxv (gdb_byte *readbuf,
+		 const gdb_byte *writebuf,
+		 ULONGEST offset,
+		 LONGEST len)
+{
+  struct minimal_symbol *msym;
+  CORE_ADDR data_address, pointer_address;
+  struct type *ptr_type = builtin_type (target_gdbarch)->builtin_data_ptr;
+  size_t ptr_size = TYPE_LENGTH (ptr_type);
+  size_t auxv_pair_size = 2 * ptr_size;
+  gdb_byte *ptr_buf = alloca (ptr_size);
+  LONGEST retval;
+  size_t block;
+
+  msym = lookup_minimal_symbol ("_dl_auxv", NULL, NULL);
+  if (msym == NULL)
+    return -1;
+
+  if (MSYMBOL_SIZE (msym) != ptr_size)
+    return -1;
+
+  /* POINTER_ADDRESS is a location where the `_dl_auxv' variable resides.
+     DATA_ADDRESS is the inferior value present in `_dl_auxv', therefore the
+     real inferior AUXV address.  */
+
+  pointer_address = SYMBOL_VALUE_ADDRESS (msym);
+
+  data_address = read_memory_typed_address (pointer_address, ptr_type);
+
+  /* Possibly still not initialized such as during an inferior startup.  */
+  if (data_address == 0)
+    return -1;
+
+  data_address += offset;
+
+  if (writebuf != NULL)
+    {
+      if (target_write_memory (data_address, writebuf, len) == 0)
+	return len;
+      else
+	return -1;
+    }
+
+  /* Stop if trying to read past the existing AUXV block.  The final AT_NULL
+     was already returned before.  */
+
+  if (offset >= auxv_pair_size)
+    {
+      if (target_read_memory (data_address - auxv_pair_size, ptr_buf,
+			      ptr_size) != 0)
+	return -1;
+
+      if (extract_typed_address (ptr_buf, ptr_type) == AT_NULL)
+	return 0;
+    }
+
+  retval = 0;
+  block = 0x400;
+  gdb_assert (block % auxv_pair_size == 0);
+
+  while (len > 0)
+    {
+      if (block > len)
+	block = len;
+
+      /* Reading sizes smaller than AUXV_PAIR_SIZE is not supported.  Tails
+	 unaligned to AUXV_PAIR_SIZE will not be read during a call (they
+	 should be completed during next read with new/extended buffer).  */
+
+      block &= -auxv_pair_size;
+      if (block == 0)
+	return retval;
+
+      if (target_read_memory (data_address, readbuf, block) != 0)
+	{
+	  if (block <= auxv_pair_size)
+	    return retval;
+
+	  block = auxv_pair_size;
+	  continue;
+	}
+
+      data_address += block;
+      len -= block;
+
+      /* Check terminal AT_NULL.  This function is being called indefinitely
+         being extended its READBUF until it returns EOF (0).  */
+
+      while (block >= auxv_pair_size)
+	{
+	  retval += auxv_pair_size;
+
+	  if (extract_typed_address (readbuf, ptr_type) == AT_NULL)
+	    return retval;
+
+	  readbuf += auxv_pair_size;
+	  block -= auxv_pair_size;
+	}
+    }
+
+  return retval;
+}
+
+/* This function is called like a to_xfer_partial hook, but must be
+   called with TARGET_OBJECT_AUXV.  It handles access to AUXV.  */
+
+LONGEST
+memory_xfer_auxv (struct target_ops *ops,
+		  enum target_object object,
+		  const char *annex,
+		  gdb_byte *readbuf,
+		  const gdb_byte *writebuf,
+		  ULONGEST offset,
+		  LONGEST len)
+{
+  gdb_assert (object == TARGET_OBJECT_AUXV);
+  gdb_assert (readbuf || writebuf);
+
+   /* ld_so_xfer_auxv is the only function safe for virtual executables being
+      executed by valgrind's memcheck.  As using ld_so_xfer_auxv is problematic
+      during inferior startup GDB does call it only for attached processes.  */
+
+  if (current_inferior ()->attach_flag != 0)
+    {
+      LONGEST retval;
+
+      retval = ld_so_xfer_auxv (readbuf, writebuf, offset, len);
+      if (retval != -1)
+	return retval;
+    }
+
+  return procfs_xfer_auxv (readbuf, writebuf, offset, len);
+}
+
 /* Read one auxv entry from *READPTR, not reading locations >= ENDPTR.
    Return 0 if *READPTR is already at the end of the buffer.
    Return -1 if there is insufficient buffer for a whole entry.

gdb/auxv.h

@@ -43,11 +43,7 @@ extern int target_auxv_search (struct target_ops *ops,
 /* Print the contents of the target's AUXV on the specified file. */
 extern int fprint_target_auxv (struct ui_file *file, struct target_ops *ops);
 
-/* This function is called like a to_xfer_partial hook, but must be
+extern LONGEST memory_xfer_auxv (struct target_ops *ops,
-   called with TARGET_OBJECT_AUXV.  It handles access via
-   /proc/PID/auxv, which is a common method for native targets.  */
-
-extern LONGEST procfs_xfer_auxv (struct target_ops *ops,
 				 enum target_object object,
 				 const char *annex,
 				 gdb_byte *readbuf,

gdb/linux-nat.c

@@ -5009,7 +5009,7 @@ linux_xfer_partial (struct target_ops *ops, enum target_object object,
   LONGEST xfer;
 
   if (object == TARGET_OBJECT_AUXV)
-    return procfs_xfer_auxv (ops, object, annex, readbuf, writebuf,
+    return memory_xfer_auxv (ops, object, annex, readbuf, writebuf,
 			     offset, len);
 
   if (object == TARGET_OBJECT_OSDATA)

gdb/procfs.c

@@ -4387,7 +4387,7 @@ procfs_xfer_partial (struct target_ops *ops, enum target_object object,
 
 #ifdef NEW_PROC_API
     case TARGET_OBJECT_AUXV:
-      return procfs_xfer_auxv (ops, object, annex, readbuf, writebuf,
+      return memory_xfer_auxv (ops, object, annex, readbuf, writebuf,
 			       offset, len);
 #endif
 

gdb/solib-svr4.c

@@ -50,6 +50,7 @@
 
 static struct link_map_offsets *svr4_fetch_link_map_offsets (void);
 static int svr4_have_link_map_offsets (void);
+static void svr4_relocate_main_executable (void);
 
 /* Link map info to include in an allocated so_list entry */
 
@@ -1540,6 +1541,7 @@ enable_break (struct svr4_info *info, int from_tty)
 static void
 svr4_special_symbol_handling (void)
 {
+  svr4_relocate_main_executable ();
 }
 
 /* Decide if the objfile needs to be relocated.  As indicated above,
@@ -1729,7 +1731,8 @@ svr4_solib_create_inferior_hook (int from_tty)
   info = get_svr4_info ();
 
   /* Relocate the main executable if necessary.  */
-  svr4_relocate_main_executable ();
+  if (current_inferior ()->attach_flag == 0)
+    svr4_relocate_main_executable ();
 
   if (!svr4_have_link_map_offsets ())
     return;

gdb/testsuite/ChangeLog

@@ -1,3 +1,7 @@
+2010-01-14  Jan Kratochvil  <jan.kratochvil@redhat.com>
+
+	* gdb.base/valgrind-db-attach.exp, gdb.base/valgrind-db-attach.c: New.
+
 2010-01-14  Jan Kratochvil  <jan.kratochvil@redhat.com>
 
 	* gdb.base/break-interp-lib.c: Include unistd.h, assert.h and stdio.h.

gdb/testsuite/gdb.base/valgrind-db-attach.c

@@ -0,0 +1,30 @@
+/* This testcase is part of GDB, the GNU debugger.
+
+   Copyright 2009 Free Software Foundation, Inc.
+
+   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/>.  */
+
+#include <stdlib.h>
+
+int main()
+{
+  void *p;
+
+  p = malloc (1);
+  if (p == NULL)
+    return 1;
+  free (p);
+  free (p);	/* double-free */
+  return 0;
+}

gdb/testsuite/gdb.base/valgrind-db-attach.exp

@@ -0,0 +1,76 @@
+# Copyright 2009 Free Software Foundation, Inc.
+
+# 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/>.
+
+set test valgrind-db-attach
+set srcfile $test.c
+set executable $test
+set binfile ${objdir}/${subdir}/${executable}
+if {[build_executable $test.exp $executable $srcfile {debug}] == -1} {
+    return -1
+}
+
+gdb_exit
+
+# remote_spawn breaks the command on each whitespace despite possible quoting.
+# Use backslash-escaped whitespace there instead:
+
+set db_command "--db-command=$GDB $INTERNAL_GDBFLAGS $GDBFLAGS [host_info gdb_opts] %f %p"
+regsub -all " " $db_command "\\ " db_command
+
+set test "spawn valgrind"
+set cmd "valgrind --db-attach=yes $db_command $binfile"
+set res [remote_spawn host $cmd];
+if { $res < 0 || $res == "" } {
+    verbose -log "Spawning $cmd failed."
+    setup_xfail *-*-*
+    fail $test
+    return -1
+}
+pass $test
+# Declare GDB now as running.
+set gdb_spawn_id -1
+
+set test "valgrind started"
+# The trailing '.' differs for different memcheck versions.
+gdb_test_multiple "" $test {
+    -re "Memcheck, a memory error detector\\.?\r\n" {
+	pass $test
+    }
+    -re "valgrind: failed to start tool 'memcheck' for platform '.*': No such file or directory" {
+	setup_xfail *-*-*
+	fail $test
+	return -1
+    }
+}
+
+set double_free [gdb_get_line_number "double-free"]
+
+gdb_test_multiple "" $test {
+    -re "Invalid free\\(\\) / delete / delete\\\[\\\]\r\n.*: main \\(${srcfile}:$double_free\\)\r\n.*---- Attach to debugger \\? --- \[^\r\n\]* ---- " {
+	send_gdb "y\r"
+    }
+    -re "---- Attach to debugger \\? --- \[^\r\n\]* ---- " {
+	send_gdb "n\r"
+	exp_continue
+    }
+}
+
+gdb_test "" "" "eat first prompt"
+
+# Initialization from default_gdb_start.
+gdb_test "set height 0"
+gdb_test "set width 0"
+
+gdb_test "bt" "in main \\(.*\\) at .*${srcfile}:$double_free"