http://sourceware.org/ml/gdb-patches/2012-09/msg00568.html

gdb/ChangeLog

        * target.c (simple_search_memory): Include access length in
        warning message.

gdb/gdbserver/ChangeLog

        * server.c (handle_search_memory_1): Include access length in
        warning message.

gdb/testsuite/ChangeLog

        Test find command on unmapped memory.
        * gdb.base/find-unmapped.c: New file.
        * gdb.base/find-unmapped.exp: New file.

2 files changed, 152 insertions, 0 deletions

diff --git a/gdb/testsuite/gdb.base/find-unmapped.c b/gdb/testsuite/gdb.base/find-unmapped.c
new file mode 100644
index 00000000000..e63dc99a94d
--- /dev/null
+++ b/gdb/testsuite/gdb.base/find-unmapped.c
@@ -0,0 +1,106 @@
+/* This testcase is part of GDB, the GNU debugger.
+
+   Copyright 2012 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>
+#include <stdio.h>
+#include <sys/mman.h>
+#include <unistd.h>
+#include <string.h>
+
+#define CHUNK_SIZE 16000 /* same as findcmd.c's */
+
+void *global_var_0;
+void *global_var_1;
+void *global_var_2;
+
+void
+breakpt ()
+{
+  /* Nothing. */
+}
+
+int
+main (void)
+{
+  void *p;
+  size_t pg_size;
+  int pg_count;
+  void *unmapped_page, *last_mapped_page, *first_mapped_page;
+
+  /*
+    Map enough pages to cover at least CHUNK_SIZE, and one extra page.  We
+    then unmap the last page.
+
+    From gdb we can then perform find commands into unmapped region, gdb
+    should give an error.
+
+    .-- global_var_0  .-- global_var_1
+    |                 |   .-- global_var_2
+    |                 |   |
+    .----.----.----.----.----.
+    |    |    |    |    |    |
+    '----'----'----'----'----'
+    |<- CHUNK_SIZE ->|
+
+    If CHUNK_SIZE equals page size then we'll get 3 pages, and if
+    CHUNK_SIZE is less than page size we'll get 2 pages.  The test will
+    still work in these cases.
+
+    (1) We do a find from global_var_0 to global_var_2, this will fail when
+    loading the second chunk, as we know at least CHUNK_SIZE bytes are in
+    mapped space.
+
+    (2) We do a find from global_var_1 to global_var_2, this will fail when
+    loading the first chunk, assuming the CHUNK_SIZE is at least 16 bytes.
+
+    (3) We do a find from global_var_2 to (global_var_2 + 16), this too
+    will fail when loading the first chunk regardless of the chunk size.
+  */
+
+  pg_size = getpagesize ();
+  /* The +2 ensures the extra page.  */
+  pg_count = CHUNK_SIZE / pg_size + 2;
+
+  p = mmap (0, pg_count * pg_size, PROT_READ|PROT_WRITE,
+	    MAP_ANONYMOUS|MAP_PRIVATE, -1, 0);
+  if (p == MAP_FAILED)
+    {
+      perror ("mmap");
+      return EXIT_FAILURE;
+    }
+
+  memset (p, 0, pg_count * pg_size);
+
+  if (munmap (p + (pg_count - 1) * pg_size, pg_size) == -1)
+    {
+      perror ("munmap");
+      return EXIT_FAILURE;
+    }
+
+  first_mapped_page = p;
+  last_mapped_page = p + (pg_count - 2) * pg_size;
+  unmapped_page = last_mapped_page + pg_size;
+
+  /* Setup global variables we reference from gdb.  */
+  global_var_0 = first_mapped_page;
+  global_var_1 = unmapped_page - 16;
+  global_var_2 = unmapped_page + 16;
+
+  breakpt ();
+
+  return EXIT_SUCCESS;
+}
diff --git a/gdb/testsuite/gdb.base/find-unmapped.exp b/gdb/testsuite/gdb.base/find-unmapped.exp
new file mode 100644
index 00000000000..66907e2e064
--- /dev/null
+++ b/gdb/testsuite/gdb.base/find-unmapped.exp
@@ -0,0 +1,46 @@
+# Copyright 2012 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/>.
+
+if {[is_remote target]} {
+    # gdbserver prints the warning message but expect is parsing only the
+    # GDB output, not the gdbserver output.
+    return 0
+}
+
+standard_testfile
+
+if { [prepare_for_testing ${testfile}.exp ${testfile}] } {
+    return -1
+}
+
+if ![runto breakpt] {
+    return -1
+}
+
+# Basic attempt to read memory from globals.
+gdb_test "x/5w global_var_1" \
+    "$hex:\[ \t\]+0\[ \t\]+0\[ \t\]+0\[ \t\]+0\r\n$hex:\[ \t\]+Cannot access memory at address $hex"
+gdb_test "x/5w global_var_2" \
+    "$hex:\[ \t\]+Cannot access memory at address $hex"
+
+# Now try a find starting from each global.
+gdb_test "find global_var_0, global_var_2, 0xff" \
+    "warning: Unable to access $decimal bytes of target memory at $hex, halting search\.\r\nPattern not found."
+
+gdb_test "find global_var_1, global_var_2, 0xff" \
+    "warning: Unable to access $decimal bytes of target memory at $hex, halting search\.\r\nPattern not found."
+
+gdb_test "find global_var_2, (global_var_2 + 16), 0xff" \
+    "warning: Unable to access $decimal bytes of target memory at $hex, halting search\.\r\nPattern not found."