FreeChainXenon/binutils-gdb
1
0
Fork 0
Code Issues Pull requests Projects Releases Packages Wiki Activity Actions

Fix another crash with gdb parameters in Python

Browse source 
While looking into the language-capturing issue, I found another way
to crash gdb using parameters from Python:

(gdb) python print(gdb.parameter('endian'))

(This is related to PR python/12188, though this patch isn't going to
fix what that bug is really about.)

The problem here is that the global variable that underlies the
"endian" parameter is initialized to NULL.  However, that's not a
valid value for an "enum" set/show parameter.

My understanding is that, in gdb, an "enum" parameter's underlying
variable must have a value that is "==" (not just strcmp-equal) to one
of the values coming from the enum array.  This invariant is relied on
in various places.

I started this patch by fixing the problem with "endian".  Then I
added some assertions to add_setshow_enum_cmd to try to catch other
problems of the same type.

This patch fixes all the problems that I found.  I also looked at all
the calls to add_setshow_enum_cmd to ensure that they were all
included in the gdb I tested.  I think they are: there are no calls in
nat-* files, or in remote-sim.c; and I was trying a build with all
targets, Python, and Guile enabled.

Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=12188
This commit is contained in:
Tom Tromey 2022-01-04 08:52:40 -07:00
parent 1da5d0e664
commit dedb7102b3
9 changed files with 41 additions and 12 deletions
Download patch file Download diff file Expand all files Collapse all files

5
gdb/arch-utils.c
View file

@ -359,7 +359,7 @@ static const char *const endian_enum[] =
endian_auto,
NULL,
};
static const char *set_endian_string;
static const char *set_endian_string = endian_auto;
enum bfd_endian
selected_byte_order (void)
@ -757,7 +757,8 @@ initialize_current_architecture (void)
list of architectures. */
{
/* Append ``auto''. */
arches.push_back ("auto");
set_architecture_string = "auto";
arches.push_back (set_architecture_string);
arches.push_back (nullptr);
set_show_commands architecture_cmds
= add_setshow_enum_cmd ("architecture", class_support,

2
gdb/arm-tdep.c
View file

@ -9802,6 +9802,8 @@ _initialize_arm_tdep ()
size_t offset = strlen ("reg-names-");
const char *style = disasm_options->name[i];
valid_disassembly_styles[j++] = &style[offset];
if (strcmp (&style[offset], "std") == 0)
disassembly_style = &style[offset];
length = snprintf (rdptr, rest, "%s - %s\n", &style[offset],
disasm_options->description[i]);
rdptr += length;

9
gdb/charset.c
View file

@ -1029,6 +1029,9 @@ _initialize_charset ()
#endif
#endif
/* Recall that the first element is always "auto". */
host_charset_name = charset_enum[0];
gdb_assert (strcmp (host_charset_name, "auto") == 0);
add_setshow_enum_cmd ("charset", class_support,
charset_enum, &host_charset_name, _("\
Set the host and target character sets."), _("\
@ -1057,6 +1060,9 @@ To see a list of the character sets GDB supports, type `set host-charset <TAB>'.
show_host_charset_name,
&setlist, &showlist);
/* Recall that the first element is always "auto". */
target_charset_name = charset_enum[0];
gdb_assert (strcmp (target_charset_name, "auto") == 0);
add_setshow_enum_cmd ("target-charset", class_support,
charset_enum, &target_charset_name, _("\
Set the target character set."), _("\
@ -1069,6 +1075,9 @@ To see a list of the character sets GDB supports, type `set target-charset'<TAB>
show_target_charset_name,
&setlist, &showlist);
/* Recall that the first element is always "auto". */
target_wide_charset_name = charset_enum[0];
gdb_assert (strcmp (target_wide_charset_name, "auto") == 0);
add_setshow_enum_cmd ("target-wide-charset", class_support,
charset_enum, &target_wide_charset_name,
_("\

10
gdb/cli/cli-decode.c
View file

@ -613,6 +613,16 @@ add_setshow_enum_cmd (const char *name,
struct cmd_list_element **set_list,
struct cmd_list_element **show_list)
{
/* We require *VAR to be initialized before this call, and
furthermore it must be == to one of the values in ENUMLIST. */
gdb_assert (var != nullptr && *var != nullptr);
for (int i = 0; ; ++i)
{
gdb_assert (enumlist[i] != nullptr);
if (*var == enumlist[i])
break;
}
set_show_commands commands
= add_setshow_cmd_full<const char *> (name, theclass, var_enum, var,
set_doc, show_doc, help_doc,

4
gdb/guile/scm-param.c
View file

@ -458,12 +458,12 @@ add_setshow_generic (enum var_types param_type, enum command_class cmd_class,
break;
case var_enum:
/* Initialize the value, just in case. */
make_setting (self).set<const char *> (self->enumeration[0]);
commands = add_setshow_enum_cmd (cmd_name, cmd_class, self->enumeration,
&self->value.cstringval, set_doc,
show_doc, help_doc, set_func, show_func,
set_list, show_list);
/* Initialize the value, just in case. */
make_setting (self).set<const char *> (self->enumeration[0]);
break;
default:

11
gdb/language.c
View file

@ -476,7 +476,8 @@ add_set_language_command ()
/* Display "auto", "local" and "unknown" first, and then the rest,
alpha sorted. */
const char **language_names_p = language_names;
*language_names_p++ = language_def (language_auto)->name ();
language = language_def (language_auto)->name ();
*language_names_p++ = language;
*language_names_p++ = "local";
*language_names_p++ = language_def (language_unknown)->name ();
const char **sort_begin = language_names_p;
@ -1150,6 +1151,8 @@ _initialize_language ()
add_alias_cmd ("c", setshow_check_cmds.show, no_class, 1, &showlist);
add_alias_cmd ("ch", setshow_check_cmds.show, no_class, 1, &showlist);
range = type_or_range_names[3];
gdb_assert (strcmp (range, "auto") == 0);
add_setshow_enum_cmd ("range", class_support, type_or_range_names,
&range,
_("Set range checking (on/warn/off/auto)."),
@ -1158,6 +1161,8 @@ _initialize_language ()
show_range_command,
&setchecklist, &showchecklist);
case_sensitive = case_sensitive_names[2];
gdb_assert (strcmp (case_sensitive, "auto") == 0);
add_setshow_enum_cmd ("case-sensitive", class_support, case_sensitive_names,
&case_sensitive, _("\
Set case sensitivity in name search (on/off/auto)."), _("\
@ -1174,10 +1179,6 @@ For Fortran the default is off; for other languages the default is on."),
add_set_language_command ();
language = "auto";
range = "auto";
case_sensitive = "auto";
/* Have the above take effect. */
set_language (language_auto);
}

4
gdb/osabi.c
View file

@ -666,11 +666,13 @@ _initialize_gdb_osabi ()
generic_elf_osabi_sniffer);
/* Register the "set osabi" command. */
user_osabi_state = osabi_auto;
set_osabi_string = gdb_osabi_available_names[0];
gdb_assert (strcmp (set_osabi_string, "auto") == 0);
add_setshow_enum_cmd ("osabi", class_support, gdb_osabi_available_names,
&set_osabi_string,
_("Set OS ABI of target."),
_("Show OS ABI of target."),
NULL, set_osabi, show_osabi,
&setlist, &showlist);
user_osabi_state = osabi_auto;
}

4
gdb/python/py-param.c
View file

@ -572,13 +572,13 @@ add_setshow_generic (int parmclass, enum command_class cmdclass,
break;
case var_enum:
/* Initialize the value, just in case. */
self->value.cstringval = self->enumeration[0];
commands = add_setshow_enum_cmd (cmd_name.get (), cmdclass,
self->enumeration,
&self->value.cstringval, set_doc,
show_doc, help_doc, get_set_value,
get_show_value, set_list, show_list);
/* Initialize the value, just in case. */
self->value.cstringval = self->enumeration[0];
break;
default:

4
gdb/testsuite/gdb.python/py-parameter.exp
View file

@ -364,3 +364,7 @@ test_really_undocumented_parameter
test_deprecated_api_parameter
test_integer_parameter
test_throwing_parameter
# This caused a gdb crash.
gdb_test "python print(gdb.parameter('endian'))" "auto" \
"print endian parameter"