From f7e5394d614db4456fc0d9598bbfa936cc7941af Mon Sep 17 00:00:00 2001 From: Simon Marchi Date: Fri, 23 Jan 2015 12:59:24 -0500 Subject: [PATCH] Catch exception in value_rtti_indirect_type In the situation described in bug 17416 [1]: * "set print object" is on; * The variable object is a pointer to a struct, and it contains an invalid value (e.g. NULL, or random uninitialized value); * The variable object (struct) has a child which is also a pointer to a struct; * We try to use "-var-list-children". ... an exception thrown in value_ind can propagate too far and leave an half-built variable object, leading to a wrong state. This patch adds a TRY_CATCH to catch it and makes value_rtti_indirect_type return NULL in that case, meaning that the type of the pointed object could not be found. A test for the fix is also added. New in v2: * Added test. * Restructured "catch" code. * Added details about the bug in commit log. gdb/Changelog: * valops.c (value_rtti_indirect_type): Catch exception thrown by value_ind. gdb/testsuite/ChangeLog * gdb.mi/mi-var-list-children-invalid-grandchild.c: New file. * gdb.mi/mi-var-list-children-invalid-grandchild.exp: New file. [1] https://sourceware.org/bugzilla/show_bug.cgi?id=17416 --- gdb/ChangeLog | 6 +++ gdb/testsuite/ChangeLog | 5 ++ .../mi-var-list-children-invalid-grandchild.c | 46 ++++++++++++++++ .../mi-var-list-children-invalid-grandchild.exp | 63 ++++++++++++++++++++++ gdb/valops.c | 22 +++++++- 5 files changed, 140 insertions(+), 2 deletions(-) create mode 100644 gdb/testsuite/gdb.mi/mi-var-list-children-invalid-grandchild.c create mode 100644 gdb/testsuite/gdb.mi/mi-var-list-children-invalid-grandchild.exp diff --git a/gdb/ChangeLog b/gdb/ChangeLog index c195f5d..10c3855 100644 --- a/gdb/ChangeLog +++ b/gdb/ChangeLog @@ -1,3 +1,9 @@ +2015-01-23 Simon Marchi + + PR gdb/17416 + * valops.c (value_rtti_indirect_type): Catch exception thrown by + value_ind. + 2015-01-15 Mark Wielaard * dwarf2read.c (read_subroutine_type): Set TYPE_NO_RETURN from diff --git a/gdb/testsuite/ChangeLog b/gdb/testsuite/ChangeLog index 5b53cdd..ba387ef 100644 --- a/gdb/testsuite/ChangeLog +++ b/gdb/testsuite/ChangeLog @@ -1,3 +1,8 @@ +2015-01-23 Simon Marchi + + * gdb.mi/mi-var-list-children-invalid-grandchild.c: New file. + * gdb.mi/mi-var-list-children-invalid-grandchild.exp: New file. + 2015-01-15 Mark Wielaard * gdb.base/noreturn-return.c: New file. diff --git a/gdb/testsuite/gdb.mi/mi-var-list-children-invalid-grandchild.c b/gdb/testsuite/gdb.mi/mi-var-list-children-invalid-grandchild.c new file mode 100644 index 0000000..ee5dd6e --- /dev/null +++ b/gdb/testsuite/gdb.mi/mi-var-list-children-invalid-grandchild.c @@ -0,0 +1,46 @@ +/* This testcase is part of GDB, the GNU debugger. + + Copyright 2015 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 . */ + +struct inner +{ + int a; +}; + +struct outer +{ + struct inner *inner; +}; + +int main (void) +{ + struct inner inner; + struct outer outer; + struct outer *p_outer; + + inner.a = 42; + outer.inner = &inner; + + /* We force p_outer to an invalid value, but this also happens naturally + * when a variable has not been initialized. */ + + p_outer = 0; + /* p_outer set to invalid value */ + p_outer = &outer; + /* p_outer set to valid value */ + + return 0; +} diff --git a/gdb/testsuite/gdb.mi/mi-var-list-children-invalid-grandchild.exp b/gdb/testsuite/gdb.mi/mi-var-list-children-invalid-grandchild.exp new file mode 100644 index 0000000..cd5db8b --- /dev/null +++ b/gdb/testsuite/gdb.mi/mi-var-list-children-invalid-grandchild.exp @@ -0,0 +1,63 @@ +# Copyright 2015 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 . + +# This is a regression test for bug 17416 +# https://sourceware.org/bugzilla/show_bug.cgi?id=17416 + +load_lib mi-support.exp +set MIFLAGS "-i=mi" + +gdb_exit +if [mi_gdb_start] { + continue +} + +standard_testfile + +if { [gdb_compile "${srcdir}/${subdir}/${srcfile}" "${binfile}" executable {debug}] != "" } { + untested mi-var-list-children-invalid-grandchild.exp + return -1 +} + +mi_delete_breakpoints +mi_gdb_reinitialize_dir $srcdir/$subdir +mi_gdb_load ${binfile} + +set line_invalid_pointer_value [gdb_get_line_number "p_outer set to invalid value"] +set line_valid_pointer_value [gdb_get_line_number "p_outer set to valid value"] + +# set print object on +mi_gdb_test "-interpreter-exec console \"set print object on\"" \ + "(.*=cmd-param-changed,param=\"print object\",value=\"on\".*|)\\^done" \ + "set print object on" + +mi_runto main + +mi_continue_to_line $line_invalid_pointer_value "continue to invalid pointer value" + +# Create variable object +mi_gdb_test "-var-create var1 * p_outer" "\\^done,name=\"var1\",numchild=\"1\",value=\"0x0\",type=\"struct outer \\*\",thread-id=\"1\",has_more=\"0\"" "create variable object" + +# List children while the pointer is uninitialized. +# Note: if you remove this -var-list-children, the second one will work. +mi_gdb_test "-var-list-children var1" "\\^done,numchild=\"1\",children=\\\[child={name=\"var1.inner\",exp=\"inner\",numchild=\"1\",type=\"struct inner \\*\",thread-id=\"1\"}\\\],has_more=\"0\"" "list children #1" + +mi_continue_to_line $line_valid_pointer_value "continue to valid pointer value" + +# Update and list children again +mi_gdb_test "-var-update var1" "\\^done,changelist=\\\[{name=\"var1\",in_scope=\"true\",type_changed=\"false\",has_more=\"0\"},{name=\"var1.inner\",in_scope=\"true\",type_changed=\"false\",has_more=\"0\"}\\\]" "update variable object" + +mi_gdb_test "-var-list-children var1" "\\^done,numchild=\"1\",children=\\\[child={name=\"var1.inner\",exp=\"inner\",numchild=\"1\",type=\"struct inner \\*\",thread-id=\"1\"}\\\],has_more=\"0\"" "list children #2" + diff --git a/gdb/valops.c b/gdb/valops.c index 27eda9f..8cbac85 100644 --- a/gdb/valops.c +++ b/gdb/valops.c @@ -3592,7 +3592,7 @@ struct type * value_rtti_indirect_type (struct value *v, int *full, int *top, int *using_enc) { - struct value *target; + struct value *target = NULL; struct type *type, *real_type, *target_type; type = value_type (v); @@ -3600,7 +3600,25 @@ value_rtti_indirect_type (struct value *v, int *full, if (TYPE_CODE (type) == TYPE_CODE_REF) target = coerce_ref (v); else if (TYPE_CODE (type) == TYPE_CODE_PTR) - target = value_ind (v); + { + volatile struct gdb_exception except; + + TRY_CATCH (except, RETURN_MASK_ERROR) + { + target = value_ind (v); + } + if (except.reason < 0) + { + if (except.error == MEMORY_ERROR) + { + /* value_ind threw a memory error. The pointer is NULL or + contains an uninitialized value: we can't determine any + type. */ + return NULL; + } + throw_exception (except); + } + } else return NULL; -- 2.7.4