PR 18303, Tolerate malformed input for lookup_symbol-called functions

lookup_symbol is often called with user input.  Consequently, any
function called from lookup_symbol{,_in_language} should attempt to
deal with malformed input gracefully.  After all, malformed user
input is not a programming/API error.

This patch does not attempt to find/correct all instances of this.  It
only fixes locations in the code that trigger test suite failures.

This patch fixes PR breakpoints/18303, "Assertion: -breakpoint-insert
with windows paths of file in non-current directory".

The patch includes three new tests related to this.  One is just
gdb.linespec/ls-errs.exp copied and converted to use C++ instead of C, and
to add a case using a file name containing a Windows-style logical drive
specifier.  The others include an MI test to provide a regression test for
the specific case reported in PR 18303, and a C++ test for proper error
handling of access to a program variable when using a file scope specifier
that refers to a non-existent file.

Tested on x86_64 native Linux.

gdb/ChangeLog
2016-01-28  Keith Seitz  <keiths@redhat.com>

	PR breakpoints/18303
	* cp-namespace.c (cp_lookup_bare_symbol): Change assertion to
	look for "::" instead of simply ":".
	(cp_search_static_and_baseclasses): Return null_block_symbol for
	malformed input.
	Remove assertions.
	* cp-support.c (cp_find_first_component_aux): Do not return
	a prefix length for ':' unless the next character is also ':'.

gdb/testsuite/ChangeLog
2016-01-28  Don Breazeal  <donb@codesourcery.com>

	* gdb.cp/scope-err.cc: New test program.
	* gdb.cp/scope-err.exp: New test script.
	* gdb.linespec/ls-errs.c (myfunction): Expanded to have multiple
	lines and "set breakpoint here" comment.
	* gdb.linespec/ls-errs.exp: Added C++ testing and new test case.
	Fixed some whitespace and format issues.
	* gdb.mi/mi-linespec-err-cp.cc: New test program.
	* gdb.mi/mi-linespec-err-cp.exp: New test script.

gdb/ChangeLog

@@ -1,3 +1,14 @@
+2016-03-15  Keith Seitz  <keiths@redhat.com>
+
+	PR breakpoints/18303
+	* cp-namespace.c (cp_lookup_bare_symbol): Change assertion to
+	look for "::" instead of simply ":".
+	(cp_search_static_and_baseclasses): Return null_block_symbol for
+	malformed input.
+	Remove assertions.
+	* cp-support.c (cp_find_first_component_aux): Do not return
+	a prefix length for ':' unless the next character is also ':'.
+
 2016-03-15  Doug Evans  <dje@google.com>
 
 	* features/aarch64-core.xml (cpsr_flags): New flags type.

gdb/cp-namespace.c

@@ -170,7 +170,7 @@ cp_lookup_bare_symbol (const struct language_defn *langdef,
      ':' may be in the args of a template spec.  This isn't intended to be
      a complete test, just cheap and documentary.  */
   if (strchr (name, '<') == NULL && strchr (name, '(') == NULL)
-    gdb_assert (strchr (name, ':') == NULL);
+    gdb_assert (strstr (name, "::") == NULL);
 
   sym = lookup_symbol_in_static_block (name, block, domain);
   if (sym.symbol != NULL)
@@ -246,10 +246,9 @@ cp_search_static_and_baseclasses (const char *name,
   struct block_symbol klass_sym;
   struct type *klass_type;
 
-  /* The test here uses <= instead of < because Fortran also uses this,
+  /* Check for malformed input.  */
-     and the module.exp testcase will pass "modmany::" for NAME here.  */
+  if (prefix_len + 2 > strlen (name) || name[prefix_len + 1] != ':')
-  gdb_assert (prefix_len + 2 <= strlen (name));
+    return null_block_symbol;
-  gdb_assert (name[prefix_len + 1] == ':');
 
   /* Find the name of the class and the name of the method, variable, etc.  */
 

gdb/cp-support.c

@@ -1037,8 +1037,13 @@ cp_find_first_component_aux (const char *name, int permissive)
 	      return strlen (name);
 	    }
 	case '\0':
-	case ':':
 	  return index;
+	case ':':
+	  /* ':' marks a component iff the next character is also a ':'.
+	     Otherwise it is probably malformed input.  */
+	  if (name[index + 1] == ':')
+	    return index;
+	  break;
 	case 'o':
 	  /* Operator names can screw up the recursion.  */
 	  if (operator_possible

gdb/testsuite/ChangeLog

@@ -1,3 +1,14 @@
+2016-03-15  Don Breazeal  <donb@codesourcery.com>
+
+	* gdb.cp/scope-err.cc: New test program.
+	* gdb.cp/scope-err.exp: New test script.
+	* gdb.linespec/ls-errs.c (myfunction): Expanded to have multiple
+	lines and "set breakpoint here" comment.
+	* gdb.linespec/ls-errs.exp: Added C++ testing and new test case.
+	Fixed some whitespace and format issues.
+	* gdb.mi/mi-linespec-err-cp.cc: New test program.
+	* gdb.mi/mi-linespec-err-cp.exp: New test script.
+
 2016-03-15  Doug Evans  <dje@google.com>
 
 	* gdb.xml/extra-regs.xml: Add enum, mixed_flags values.

gdb/testsuite/gdb.cp/scope-err.cc

@@ -0,0 +1,35 @@
+/* This testcase is part of GDB, the GNU debugger.
+
+   Copyright 2016 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/>.  */
+
+int
+myfunction (int aa)
+{
+  int i;
+
+  i = aa + 42;
+  return i;    /* set breakpoint here */
+}
+
+int
+main (void)
+{
+  int a;
+
+  a = myfunction (a);
+
+  return a;
+}

gdb/testsuite/gdb.cp/scope-err.exp

@@ -0,0 +1,49 @@
+# Copyright 2012-2016 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/>.
+
+# Tests for linespec errors with C++.
+# Derived from gdb.linespec/ls-errs.exp.
+
+if {[skip_cplus_tests]} {
+    continue
+}
+
+standard_testfile .cc
+set exefile $testfile
+
+if {[prepare_for_testing $testfile $exefile $srcfile {debug c++}]} {
+    return -1
+}
+
+if {![runto_main]} {
+    fail "Can't run to main"
+    return 0
+}
+
+# Run to a location in the file.
+set bp_location [gdb_get_line_number "set breakpoint here"]
+
+gdb_test "break $srcfile:$bp_location" \
+    "Breakpoint.*at.* file .*$srcfile, line $bp_location\\." \
+    "breakpoint line number in file"
+
+gdb_continue_to_breakpoint "$bp_location"
+
+# Try to access a variable using scope that is a non-existent filename
+# with a Windows-style logical drive in the name.
+set nonexistent_file C:/does/not/exist.cc
+gdb_test "print '$nonexistent_file'::var" \
+	 ".*No symbol \"$nonexistent_file\" in current context.*" \
+	 "print var from \"$nonexistent_file\""

gdb/testsuite/gdb.linespec/ls-errs.c

@@ -15,14 +15,21 @@
    You should have received a copy of the GNU General Public License
    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
 
-int myfunction (void) { return 0; }
+int
+myfunction (int aa)
+{
+  int i;
+
+  i = aa + 42;
+  return i;    /* set breakpoint here */
+}
 
 int
 main (void)
 {
   int a;
 
-  a = myfunction ();
+  a = myfunction (a);
 
  here:
   return a;

gdb/testsuite/gdb.linespec/ls-errs.exp

@@ -13,13 +13,31 @@
 # You should have received a copy of the GNU General Public License
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
-# Tests for linespec error conditions
+# Tests for linespec errors with C and C++.
+
+# The test proper.  LANG is either C or C++.
+
+proc do_test {lang} {
+    global testfile srcfile error_messages compiler_info
 
     standard_testfile
     set exefile $testfile
+    if [info exists compiler_info] {
+	# Unsetting compiler_info allows us to switch compilers
+	# used by prepare_for_testing.
+        unset compiler_info
+    }
+    set options {debug}
 
-if {[prepare_for_testing $testfile $exefile $srcfile \
+    if {$lang == "C++"} {
-	 {debug nowarnings}]} {
+	if {[skip_cplus_tests]} {
+	    return 0
+	}
+	# Build ".c" source file with g++.
+	lappend options "c++"
+    }
+
+    if {[prepare_for_testing $testfile $exefile $srcfile $options]} {
 	return -1
     }
 
@@ -29,22 +47,26 @@ gdb_test_no_output "set breakpoint pending off"
     # Turn off completion limiting
     gdb_test_no_output "set max-completions unlimited"
 
-# We intentionally do not use gdb_breakpoint for these tests.
+    if {![runto_main]} {
-
+	fail "Can't run to main"
-# Break at 'linespec' and expect the message in ::error_messages indexed by
+	return 0
-# msg_id with the associated args.
-proc test_break {linespec msg_id args} {
-    global error_messages
-
-    gdb_test "break $linespec" [string_to_regexp \
-				[eval format \$error_messages($msg_id) $args]]
     }
 
+    # Run to a location in the file.
+    set bp_location [gdb_get_line_number "set breakpoint here"]
+
+    gdb_test "break $srcfile:$bp_location" \
+    "Breakpoint.*at.* file .*$srcfile, line $bp_location\\." \
+    "breakpoint line number in file"
+
+    gdb_continue_to_breakpoint "$bp_location"
+
     # Common error message format strings.
     array set error_messages {
 	invalid_file "No source file named %s."
 	invalid_function "Function \"%s\" not defined."
-    invalid_var_or_func "Undefined convenience variable or function \"%s\" not defined."
+	invalid_var_or_func
+	    "Undefined convenience variable or function \"%s\" not defined."
 	invalid_function_f "Function \"%s\" not defined in \"%s\"."
 	invalid_var_or_func_f \
 	    "Undefined convenience variable or function \"%s\" not defined in \"%s\"."
@@ -61,9 +83,21 @@ array set error_messages {
 	garbage "Garbage '%s' at end of command"
     }
 
+    # We intentionally do not use gdb_breakpoint for these tests.
+
+    # Break at 'linespec' and expect the message in ::error_messages
+    # indexed by msg_id with the associated args.
+    proc test_break {linespec msg_id args} {
+	global error_messages
+
+	gdb_test "break $linespec" [string_to_regexp \
+				    [eval format \$error_messages($msg_id) \
+				     $args]]
+    }
+
     # Some commonly used whitespace tests around ':'.
-set spaces [list ":" ": " " :" " : " "\t:  " "  :\t" "\t:\t" " \t:\t " \
+    set spaces [list ":" ": " " :" " : " "\t:  " "  :\t" "\t:\t" \
-		"\t  \t:\t  \t  \t"]
+		     " \t:\t " "\t  \t:\t  \t  \t"]
 
     # A list of invalid offsets.
     set invalid_offsets [list -100 +500 1000]
@@ -80,9 +114,8 @@ foreach x $invalid_offsets {
 
 	# Relative offsets are relative to line 16.  Adjust
 	# expected offset from error message accordingly.
-    if {[string index $x 0] == "+" ||
+	if {[string index $x 0] == "+" || [string index $x 0] == "-"} {
-	[string index $x 0] == "-"} {
+	    incr offset 24
-	incr offset 16
 	}
 	test_break $x invalid_offset $offset
 	test_break "-line $x" invalid_offset $offset
@@ -110,7 +143,9 @@ foreach x {3 +10 -10} {
     }
 
     # Test invalid linespecs starting with filename.
-foreach x [list "this_file_doesn't_exist.c" \
+    # It's OK to use the ".c" extension for the C++ test
+    # since the extension doesn't affect GDB's lookup.
+    set invalid_files [list "this_file_doesn't_exist.c" \
 			    "this file has spaces.c" \
 			    "\"file::colons.c\"" \
 			    "'file::colons.c'" \
@@ -119,24 +154,22 @@ foreach x [list "this_file_doesn't_exist.c" \
 			    "'this 'file' has quotes.c'" \
 			    "\"this 'file' has quotes.c\"" \
 			    "\"spaces: and :colons.c\"" \
-	       "'more: :spaces: :and  colons::.c'"] {
+			    "'more: :spaces: :and  colons::.c'" \
+			    "C:/nonexist-with-windrive.c"]
+
+    foreach x $invalid_files {
 	# Remove any quoting from FILENAME for the error message.
 	test_break "$x:3" invalid_file [string trim $x \"']
     }
     foreach x [list "this_file_doesn't_exist.c" \
 		    "file::colons.c" \
 		    "'file::colons.c'"] {
-    test_break "-source $x -line 3" \
+	test_break "-source $x -line 3" invalid_file [string trim $x \"']
-	invalid_file [string trim $x \"']
     }
 
     # Test that option lexing stops at whitespace boundaries
-test_break "-source this file has spaces.c -line 3" \
+    test_break "-source this file has spaces.c -line 3" invalid_file "this"
-    invalid_file "this"
+    test_break "-function function whitespace" invalid_function "function"
-
-test_break "-function function whitespace" \
-    invalid_function "function"
-
     test_break "-source $srcfile -function function whitespace" \
 	       invalid_function_f "function" $srcfile
 
@@ -190,7 +223,9 @@ foreach x {"foobar" "foo::bar" "foo.bar" "foo ." "foo bar" "foo 1" \
 
     foreach x $spaces {
 	test_break "main${x}there" invalid_label "there" "main"
-    if {[test_compiler_info {clang-*-*}]} {  setup_xfail clang/14500 *-*-* }
+	if {[test_compiler_info {clang-*-*}]} {
+	    setup_xfail clang/14500 *-*-*
+	}
 	test_break "main:here${x}" unexpected "end of input"
     }
 
@@ -219,3 +254,8 @@ test_break "$srcfile:$x" invalid_var_or_func_f $x $srcfile
 
     # Explicit linespec-specific tests
     test_break "-source $srcfile" source_incomplete
+}
+
+foreach_with_prefix lang {"C" "C++"} {
+    do_test ${lang}
+}

gdb/testsuite/gdb.mi/mi-linespec-err-cp.cc

@@ -0,0 +1,35 @@
+/* This testcase is part of GDB, the GNU debugger.
+
+   Copyright 2016 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/>.  */
+
+int
+myfunction (int aa)
+{
+  int i;
+
+  i = aa + 42;
+  return i;    /* set breakpoint here */
+}
+
+int
+main (void)
+{
+  int a;
+
+  a = myfunction (a);
+
+  return a;
+}

gdb/testsuite/gdb.mi/mi-linespec-err-cp.exp

@@ -0,0 +1,59 @@
+# Copyright 2016 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/>.
+
+# Regression test for PR breakpoints/18303.  Tests that the correct
+# errors is generated when setting a breakpoint in a non-existent
+# file with a Windows-style logical drive names and C++.
+
+if {[skip_cplus_tests]} {
+    continue
+}
+
+load_lib mi-support.exp
+set MIFLAGS "-i=mi"
+
+standard_testfile .cc
+set exefile $testfile
+
+if {[prepare_for_testing $testfile $exefile $srcfile {debug c++}]} {
+    return -1
+}
+
+gdb_exit
+if {[mi_gdb_start]} {
+    continue
+}
+
+# Turn off the pending breakpoint queries.
+mi_gdb_test "-interpreter-exec console \"set breakpoint pending off\"" \
+  {=cmd-param-changed,param=\"breakpoint pending\",.*\^done} \
+  "-interpreter-exec console \"set breakpoint pending off\""
+
+mi_run_to_main
+
+# Run to a location in the file.
+set bp_location [gdb_get_line_number "set breakpoint here"]
+
+mi_gdb_test "-break-insert ${srcfile}:${bp_location}" \
+    {\^done,bkpt=.number="2",type="breakpoint".*\}} "set breakpoint"
+
+mi_execute_to "exec-continue" "breakpoint-hit" "myfunction" ".*" ".*" "24" \
+    { "" "disp=\"keep\"" } "breakpoint hit"
+
+# Set a breakpoint in a C++ source file whose name contains a
+# Windows-style logical drive.
+mi_gdb_test \
+    "-break-insert -f \"c:/uu.cpp:13\"" \
+    ".*No source file named c:/uu.cpp.*"