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List: gdb-cvs
Subject: [binutils-gdb] Implement show | set may-call-functions [on|off]
From: Philippe Waroquiers <philippe () sourceware ! org>
Date: 2019-04-27 11:24:44
Message-ID: 20190427112444.93031.qmail () sourceware ! org
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https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;h=136afab8c7d8a8a91dbf38e79be4f9dc4125d552
commit 136afab8c7d8a8a91dbf38e79be4f9dc4125d552
Author: Philippe Waroquiers <philippe.waroquiers@skynet.be>
Date: Tue Apr 23 23:43:24 2019 +0200
Implement show | set may-call-functions [on|off]
Inferior function calls are powerful but might lead to undesired
results such as crashes when calling nested functions (frequently
used in particular in Ada).
This implements a GDB setting to disable calling inferior functions.
Note: the idea is that if/when the 'slash command' patch is pushed,
that this setting can be changed e.g. by using the shortcut /c.
This is version 2 of the patch. It handles all the received comments,
mostly replace 'can-call' by 'may-call', and avoid using
'inferior function call' in factor of 'calling function in the program'.
2019-04-26 Philippe Waroquiers <philippe.waroquiers@skynet.be>
gdb/ChangeLog
* NEWS: Mention the new set|show may-call-functions.
* infcall.c (may_call_functions_p): New variable.
(show_may_call_functions_p): New function.
(call_function_by_hand_dummy): Throws an error if not
may-call-functions.
(_initialize_infcall): Call add_setshow_boolean_cmd for
may-call-functions.
gdb/testsuite/ChangeLog
* gdb.base/callexit.exp: Test may-call-functions off.
gdb/doc/ChangeLog
* gdb.texinfo (Calling): Document the new
set|show may-call-functions.
Diff:
---
gdb/ChangeLog | 10 ++++++++++
gdb/NEWS | 12 ++++++++++++
gdb/doc/ChangeLog | 5 +++++
gdb/doc/gdb.texinfo | 22 ++++++++++++++++++++++
gdb/infcall.c | 26 ++++++++++++++++++++++++++
gdb/testsuite/ChangeLog | 4 ++++
gdb/testsuite/gdb.base/callexit.exp | 7 +++++++
7 files changed, 86 insertions(+)
diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index e0120e7..58aa736 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,3 +1,13 @@
+2019-04-27 Philippe Waroquiers <philippe.waroquiers@skynet.be>
+
+ * NEWS: Mention the new set|show may-call-functions.
+ * infcall.c (may_call_functions_p): New variable.
+ (show_may_call_functions_p): New function.
+ (call_function_by_hand_dummy): Throws an error if not
+ may-call-functions.
+ (_initialize_infcall): Call add_setshow_boolean_cmd for
+ may-call-functions.
+
2019-04-25 Keith Seitz <keiths@redhat.com>
PR c++/24367
diff --git a/gdb/NEWS b/gdb/NEWS
index 5309a8f..42b04e9 100644
--- a/gdb/NEWS
+++ b/gdb/NEWS
@@ -27,6 +27,18 @@
'array_indexes', 'symbols', 'unions', 'deref_refs', 'actual_objects',
'static_members', 'max_elements', 'repeat_threshold', and 'format'.
+* New commands
+
+set may-call-functions [on|off]
+show may-call-functions
+ This controls whether GDB will attempt to call functions in
+ the program, such as with expressions in the print command. It
+ defaults to on. Calling functions in the program being debugged
+ can have undesired side effects. It is now possible to forbid
+ such function calls. If function calls are forbidden, GDB will throw
+ an error when a command (such as print expression) calls a function
+ in the program.
+
*** Changes in GDB 8.3
* GDB and GDBserver now support access to additional registers on
diff --git a/gdb/doc/ChangeLog b/gdb/doc/ChangeLog
index ba15232..3efed67 100644
--- a/gdb/doc/ChangeLog
+++ b/gdb/doc/ChangeLog
@@ -1,3 +1,8 @@
+2019-04-27 Philippe Waroquiers <philippe.waroquiers@skynet.be>
+
+ * gdb.texinfo (Calling): Document the new
+ set|show may-call-functions.
+
2019-04-22 Pedro Alves <palves@redhat.com>
* gdb.texinfo (Reverse Execution): Mention and xref process record
diff --git a/gdb/doc/gdb.texinfo b/gdb/doc/gdb.texinfo
index 0733e1a..cf8333d 100644
--- a/gdb/doc/gdb.texinfo
+++ b/gdb/doc/gdb.texinfo
@@ -18693,6 +18693,28 @@ the default C@t{++} exception handler and the inferior terminated.
Show the current setting of stack unwinding in the functions called by
@value{GDBN}.
+@item set may-call-functions
+@kindex set may-call-functions
+@cindex disabling calling functions in the program
+@cindex calling functions in the program, disabling
+Set permission to call functions in the program.
+This controls whether @value{GDBN} will attempt to call functions in
+the program, such as with expressions in the @code{print} command. It
+defaults to @code{on}.
+
+To call a function in the program, @value{GDBN} has to temporarily
+modify the state of the inferior. This has potentially undesired side
+effects. Also, having @value{GDBN} call nested functions is likely to
+be erroneous and may even crash the program being debugged. You can
+avoid such hazards by forbidding @value{GDBN} from calling functions
+in the program being debugged. If calling functions in the program
+is forbidden, GDB will throw an error when a command (such as printing
+an expression) starts a function call in the program.
+
+@item show may-call-functions
+@kindex show may-call-functions
+Show permission to call functions in the program.
+
@end table
@subsection Calling functions with no debug info
diff --git a/gdb/infcall.c b/gdb/infcall.c
index af60fdc..f99206c 100644
--- a/gdb/infcall.c
+++ b/gdb/infcall.c
@@ -55,6 +55,17 @@
asynchronous inferior function call implementation, and that in
turn means restructuring the code so that it is event driven. */
+static int may_call_functions_p = 1;
+static void
+show_may_call_functions_p (struct ui_file *file, int from_tty,
+ struct cmd_list_element *c,
+ const char *value)
+{
+ fprintf_filtered (file,
+ _("Permission to call functions in the program is %s.\n"),
+ value);
+}
+
/* How you should pass arguments to a function depends on whether it
was defined in K&R style or prototype style. If you define a
function using the K&R syntax that takes a `float' argument, then
@@ -708,6 +719,10 @@ call_function_by_hand_dummy (struct value *function,
struct gdb_exception e;
char name_buf[RAW_FUNCTION_ADDRESS_SIZE];
+ if (!may_call_functions_p)
+ error (_("Cannot call functions in the program: "
+ "may-call-functions is off."));
+
if (!target_has_execution)
noprocess ();
@@ -1359,6 +1374,17 @@ When the function is done executing, GDB will silently stop."),
void
_initialize_infcall (void)
{
+ add_setshow_boolean_cmd ("may-call-functions", no_class,
+ &may_call_functions_p, _("\
+Set permission to call functions in the program."), _("\
+Show permission to call functions in the program."), _("\
+When this permission is on, GDB may call functions in the program.\n\
+Otherwise, any sort of attempt to call a function in the program\n\
+will result in an error."),
+ NULL,
+ show_may_call_functions_p,
+ &setlist, &showlist);
+
add_setshow_boolean_cmd ("coerce-float-to-double", class_obscure,
&coerce_float_to_double_p, _("\
Set coercion of floats to doubles when calling functions."), _("\
diff --git a/gdb/testsuite/ChangeLog b/gdb/testsuite/ChangeLog
index 9b0725a..e814093 100644
--- a/gdb/testsuite/ChangeLog
+++ b/gdb/testsuite/ChangeLog
@@ -1,3 +1,7 @@
+2019-04-27 Philippe Waroquiers <philippe.waroquiers@skynet.be>
+
+ * gdb.base/callexit.exp: Test may-call-functions off.
+
2019-04-25 Keith Seitz <keiths@redhat.com>
PR c++/24367
diff --git a/gdb/testsuite/gdb.base/callexit.exp b/gdb/testsuite/gdb.base/callexit.exp
index b6d9ae3..9a32d3d 100644
--- a/gdb/testsuite/gdb.base/callexit.exp
+++ b/gdb/testsuite/gdb.base/callexit.exp
@@ -37,6 +37,13 @@ if { ![runto_main] } {
return 0
}
+# Verify set may-call-functions behaviour.
+gdb_test_no_output "set may-call-functions off"
+gdb_test "call callexit()" \
+ "Cannot call functions in the program: may-call-functions is off." \
+ "inferior function call refused in off state"
+gdb_test_no_output "set may-call-functions on"
+
# Call function (causing the program to exit), and see if gdb handles
# it properly.
gdb_test "call callexit()" \
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