From 2df4d1d5c4393fd06c2bffe75499e70a8d8ac8a8 Mon Sep 17 00:00:00 2001 From: Joel Brobecker Date: Wed, 30 Oct 2013 11:18:24 +0100 Subject: [PATCH] Dandling memory pointers in Ada catchpoints with GDB/MI. When using the GDB/MI commands to insert a catchpoint on a specific Ada exception, any re-evaluation of that catchpoint (for instance a re-evaluation performed after a shared library got mapped by the inferior) fails. For instance, with any Ada program: (gdb) -catch-exception -e program_error ^done,bkptno="1",bkpt={[...]} (gdb) -exec-run =thread-group-started,id="i1",pid="28315" =thread-created,id="1",group-id="i1" ^running *running,thread-id="all" (gdb) =library-loaded,[...] &"warning: failed to reevaluate internal exception condition for catchpoint 1: No definition of \"exec\" in current context.\n" &"warning: failed to reevaluate internal exception condition for catchpoint 1: No definition of \"exec\" in current context.\n" [...] The same is true if using an Ada exception catchpoint. The problem comes from the fact that that we deallocate the strings given as arguments to create_ada_exception_catchpoint, while the latter just makes shallow copies of those strings, thus creating dandling pointers. This patch fixes the issue by passing freshly allocated strings to create_ada_exception_catchpoint, while at the same time updating create_ada_exception_catchpoint's documentation to make it clear that deallocating the strings is no longer the responsibility of the caller. gdb/ChangeLog: * ada-lang.c (create_ada_exception_catchpoint): Enhance the documentation of fields "except_string" and "condition". * mi/mi-cmd-catch.c (mi_cmd_catch_assert): Reallocate CONDITION on the heap before passing it to create_ada_exception_catchpoint. (mi_cmd_catch_exception): Likewise for EXCEPTION_NAME and CONDITION. gdb/testsuite/ChangeLog: * gdb.ada/mi_ex_cond: New testcase. Tested on x86_64-linux. The "-break-list" test FAILs without this patch. --- gdb/ChangeLog | 10 +++ gdb/ada-lang.c | 14 ++-- gdb/mi/mi-cmd-catch.c | 10 +++ gdb/testsuite/ChangeLog | 4 + gdb/testsuite/gdb.ada/mi_ex_cond.exp | 94 ++++++++++++++++++++++++ gdb/testsuite/gdb.ada/mi_ex_cond/foo.adb | 29 ++++++++ gdb/testsuite/gdb.ada/mi_ex_cond/pck.ads | 18 +++++ 7 files changed, 174 insertions(+), 5 deletions(-) create mode 100644 gdb/testsuite/gdb.ada/mi_ex_cond.exp create mode 100644 gdb/testsuite/gdb.ada/mi_ex_cond/foo.adb create mode 100644 gdb/testsuite/gdb.ada/mi_ex_cond/pck.ads diff --git a/gdb/ChangeLog b/gdb/ChangeLog index c35ed65a834..3445b04c2af 100644 --- a/gdb/ChangeLog +++ b/gdb/ChangeLog @@ -1,3 +1,13 @@ +2013-11-11 Joel Brobecker + + * ada-lang.c (create_ada_exception_catchpoint): Enhance + the documentation of fields "except_string" and "condition". + * mi/mi-cmd-catch.c (mi_cmd_catch_assert): Reallocate + CONDITION on the heap before passing it to + create_ada_exception_catchpoint. + (mi_cmd_catch_exception): Likewise for EXCEPTION_NAME and + CONDITION. + 2013-11-11 Tom Tromey * config.in, configure: Rebuild. diff --git a/gdb/ada-lang.c b/gdb/ada-lang.c index 4b554608d8d..781713266ed 100644 --- a/gdb/ada-lang.c +++ b/gdb/ada-lang.c @@ -12170,11 +12170,15 @@ ada_exception_sal (enum ada_exception_catchpoint_kind ex, char *excep_string, EX_KIND is the kind of exception catchpoint to be created. - EXCEPT_STRING, if not NULL, indicates the name of the exception - to which this catchpoint applies. If NULL, this catchpoint is - expected to trigger for all exceptions. - - COND_STRING, if not NULL, is the catchpoint condition. + If EXCEPT_STRING is NULL, this catchpoint is expected to trigger + for all exceptions. Otherwise, EXCEPT_STRING indicates the name + of the exception to which this catchpoint applies. When not NULL, + the string must be allocated on the heap, and its deallocation + is no longer the responsibility of the caller. + + COND_STRING, if not NULL, is the catchpoint condition. This string + must be allocated on the heap, and its deallocation is no longer + the responsibility of the caller. TEMPFLAG, if nonzero, means that the underlying breakpoint should be temporary. diff --git a/gdb/mi/mi-cmd-catch.c b/gdb/mi/mi-cmd-catch.c index 23e30d086e0..bcfc1bad204 100644 --- a/gdb/mi/mi-cmd-catch.c +++ b/gdb/mi/mi-cmd-catch.c @@ -81,6 +81,10 @@ mi_cmd_catch_assert (char *cmd, char *argv[], int argc) error (_("Invalid argument: %s"), argv[oind]); setup_breakpoint_reporting (); + /* create_ada_exception_catchpoint needs CONDITION to be xstrdup'ed, + and will assume control of its lifetime. */ + if (condition != NULL) + condition = xstrdup (condition); create_ada_exception_catchpoint (gdbarch, ada_catch_assert, NULL, condition, temp, enabled, 0); } @@ -154,6 +158,12 @@ mi_cmd_catch_exception (char *cmd, char *argv[], int argc) error (_("\"-e\" and \"-u\" are mutually exclusive")); setup_breakpoint_reporting (); + /* create_ada_exception_catchpoint needs EXCEPTION_NAME and CONDITION + to be xstrdup'ed, and will assume control of their lifetime. */ + if (exception_name != NULL) + exception_name = xstrdup (exception_name); + if (condition != NULL) + condition = xstrdup (condition); create_ada_exception_catchpoint (gdbarch, ex_kind, exception_name, condition, temp, enabled, 0); diff --git a/gdb/testsuite/ChangeLog b/gdb/testsuite/ChangeLog index 6a88d6c6588..fb1dc5745ff 100644 --- a/gdb/testsuite/ChangeLog +++ b/gdb/testsuite/ChangeLog @@ -1,3 +1,7 @@ +2013-11-11 Joel Brobecker + + * gdb.ada/mi_ex_cond: New testcase. + 2013-11-07 Doug Evans PR 11786 diff --git a/gdb/testsuite/gdb.ada/mi_ex_cond.exp b/gdb/testsuite/gdb.ada/mi_ex_cond.exp new file mode 100644 index 00000000000..9144102bbff --- /dev/null +++ b/gdb/testsuite/gdb.ada/mi_ex_cond.exp @@ -0,0 +1,94 @@ +# Copyright 2013 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 . + +load_lib "ada.exp" + +standard_ada_testfile foo + +if {[gdb_compile_ada "${srcfile}" "${binfile}" executable [list debug additional_flags=-bargs additional_flags=-static additional_flags=-margs ]] != "" } { + return -1 +} + +# # Some global variables used to simplify the maintenance of some of +# # the regular expressions below. +set any_nb "\[0-9\]+" +set eol "\[\r\n\]+" + +# Before going any further, verify that we can insert exception +# catchpoints... That way, we won't have to do this while doing +# the actual GDB/MI testing. + +clean_restart ${testfile} + +if ![runto_main] then { + fail "Cannot run to main, testcase aborted" + return 0 +} + +set msg "insert catchpoint on all Ada exceptions" +gdb_test_multiple "catch exception" $msg { + -re "Catchpoint $any_nb: all Ada exceptions$eol$gdb_prompt $" { + pass $msg + } + -re "Your Ada runtime appears to be missing some debugging information.*\[\r\n\]+$gdb_prompt $" { + # If the runtime was not built with enough debug information, + # or if it was stripped, we can not test exception + # catchpoints. + unsupported $msg + return -1 + } +} + +# Now, we can start the GDB/MI testing itself... + +load_lib mi-support.exp +set MIFLAGS "-i=mi" + +gdb_exit +if [mi_gdb_start] { + continue +} + +mi_delete_breakpoints +mi_gdb_reinitialize_dir $srcdir/$subdir +mi_gdb_load ${binfile} + +# And finally, the meat of the testcase... Insert an Ada exception +# catchpoint that uses both conditions and exception name. + +mi_gdb_test "-catch-exception -c \"i = 2\" -e constraint_error" \ + "\\^done,bkptno=\"$decimal\",bkpt={.*disp=\"keep\",enabled=\"y\",addr=\"$hex\",what=\"`constraint_error' Ada exception\",.*,cond=\"i = 2\",.*}" \ + "catch C_E if i = 2" + +# It is important that we start the program's execution after having +# inserted the exception catchpoint above. We want to verify that +# we are able to re-evaluate the exception catchpoint exception +# address and stop condition without problems when new shared libraries +# get mapped (during program startup). + +mi_run_cmd + +mi_expect_stop \ + "breakpoint-hit\",disp=\"keep\",bkptno=\"$any_nb\",exception-name=\"CONSTRAINT_ERROR" \ + "foo" "" ".*" ".*" \ + ".*" \ + "run to exception catchpoint hit" + +# Make sure that any of the catchpoint re-evaluations didn't cause +# a clobbering of some of the exeption's info. + +mi_gdb_test "-break-list" \ + "\\^done,.*,what=\"`constraint_error' Ada exception\",.*,cond=\"i = 2\",.*" \ + "-break-list" diff --git a/gdb/testsuite/gdb.ada/mi_ex_cond/foo.adb b/gdb/testsuite/gdb.ada/mi_ex_cond/foo.adb new file mode 100644 index 00000000000..9db123329a4 --- /dev/null +++ b/gdb/testsuite/gdb.ada/mi_ex_cond/foo.adb @@ -0,0 +1,29 @@ +-- Copyright 2013 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 . + +with Pck; use Pck; + +procedure Foo is +begin + while I <= 3 loop + begin + raise Constraint_Error; + exception + when others => + null; + end; + I := I + 1; + end loop; +end Foo; diff --git a/gdb/testsuite/gdb.ada/mi_ex_cond/pck.ads b/gdb/testsuite/gdb.ada/mi_ex_cond/pck.ads new file mode 100644 index 00000000000..0ac131cd008 --- /dev/null +++ b/gdb/testsuite/gdb.ada/mi_ex_cond/pck.ads @@ -0,0 +1,18 @@ +-- Copyright 2013 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 . + +package Pck is + I : Integer := 1; +end Pck; -- 2.30.2