Fix restoring of inferior terminal settings
Commit Message
I noticed that the child_terminal_save_inferior function was not used
since the commit f6ac5f3d63e0 ("Convert struct target_ops to C++"). I
was able to make a little test program to illustrate the problem (see
test case).
I think we're just missing the override of the terminal_save_inferior
method in inf_child_target (along with the other terminal-related
methods).
Instead of creating a new test, I thought that gdb.base/term.exp was a
good candidate for testing that gdb restores properly the inferior's
terminal settings.
gdb/ChangeLog:
* inf-child.h (inf_child_target) <terminal_save_inferior>: New.
* inf-child.c (inf_child_target::terminal_save_inferior): New.
gdb/testsuite/ChangeLog:
* gdb.base/term.exp: Compare terminal settings with values from
the inferior.
* gdb.base/term.c: Get and set terminal settings.
---
gdb/inf-child.c | 6 +++
gdb/inf-child.h | 1 +
gdb/testsuite/gdb.base/term.c | 22 +++++++++
gdb/testsuite/gdb.base/term.exp | 81 ++++++++++++++++++++++++++++-----
4 files changed, 99 insertions(+), 11 deletions(-)
Comments
>>>>> "Simon" == Simon Marchi <simon.marchi@polymtl.ca> writes:
Simon> I noticed that the child_terminal_save_inferior function was not used
Simon> since the commit f6ac5f3d63e0 ("Convert struct target_ops to C++"). I
Simon> was able to make a little test program to illustrate the problem (see
Simon> test case).
Simon> I think we're just missing the override of the terminal_save_inferior
Simon> method in inf_child_target (along with the other terminal-related
Simon> methods).
Simon> Instead of creating a new test, I thought that gdb.base/term.exp was a
Simon> good candidate for testing that gdb restores properly the inferior's
Simon> terminal settings.
Thanks, this patch looks good to me.
I wonder if this is related to the suspend bug that Tom de Vries referred to.
Tom
On 2018-07-25 16:16, Tom Tromey wrote:
>>>>>> "Simon" == Simon Marchi <simon.marchi@polymtl.ca> writes:
>
> Simon> I noticed that the child_terminal_save_inferior function was not
> used
> Simon> since the commit f6ac5f3d63e0 ("Convert struct target_ops to
> C++"). I
> Simon> was able to make a little test program to illustrate the problem
> (see
> Simon> test case).
>
> Simon> I think we're just missing the override of the
> terminal_save_inferior
> Simon> method in inf_child_target (along with the other
> terminal-related
> Simon> methods).
>
> Simon> Instead of creating a new test, I thought that gdb.base/term.exp
> was a
> Simon> good candidate for testing that gdb restores properly the
> inferior's
> Simon> terminal settings.
>
> Thanks, this patch looks good to me.
Thanks, I pushed it.
> I wonder if this is related to the suspend bug that Tom de Vries
> referred to.
I don't know, I have seen a few cases of GDB getting suspended like
that, especially in error cases. I think it's more that we miss calling
target_terminal::{ours,ours_for_output} in these situations.
Simon
@@ -113,6 +113,12 @@ inf_child_target::terminal_inferior ()
child_terminal_inferior (this);
}
+void
+inf_child_target::terminal_save_inferior ()
+{
+ child_terminal_save_inferior (this);
+}
+
void
inf_child_target::terminal_ours_for_output ()
{
@@ -46,6 +46,7 @@ public:
bool supports_terminal_ours () override;
void terminal_init () override;
void terminal_inferior () override;
+ void terminal_save_inferior () override;
void terminal_ours_for_output () override;
void terminal_ours () override;
void terminal_info (const char *, int) override;
@@ -15,7 +15,29 @@
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>. */
+#include <termios.h>
+#include <unistd.h>
+
+static struct termios t;
+
+static void
+break_here ()
+{
+}
+
int main ()
{
+ tcgetattr (0, &t);
+ break_here ();
+
+ /* Disable ECHO. */
+ t.c_lflag &= ~ECHO;
+ tcsetattr (0, TCSANOW, &t);
+ tcgetattr (0, &t);
+ break_here ();
+
+ tcgetattr (0, &t);
+ break_here ();
+
return 0;
}
@@ -13,6 +13,9 @@
# You should have received a copy of the GNU General Public License
# along with this program. If not, see <http://www.gnu.org/licenses/>.
+# Test that GDB saves and restores terminal settings correctly. Also check
+# the output of the "info terminal" command.
+
if { [prepare_for_testing "failed to prepare" term term.c] } {
return -1
}
@@ -20,28 +23,84 @@ if { [prepare_for_testing "failed to prepare" term term.c] } {
# Once before running the program.
gdb_test "info terminal" \
"No saved terminal information.*" \
- "test info terminal"
+ "test info terminal pre-execution"
-if ![runto_main] then {
- fail "can't run to main"
+if ![runto break_here] then {
+ fail "can't run to break_here"
return 0
}
-# Once while the program is running and stopped.
+# Read the inferior's terminal settings, saved in the T global variable.
+
+proc read_term_settings_from_inferior {} {
+ set termios(c_iflag) [get_hexadecimal_valueof "t.c_iflag" oops]
+ set termios(c_oflag) [get_hexadecimal_valueof "t.c_oflag" oops]
+ set termios(c_cflag) [get_hexadecimal_valueof "t.c_cflag" oops]
+ set termios(c_lflag) [get_hexadecimal_valueof "t.c_lflag" oops]
+
+ return [array get termios]
+}
+
+# Validate that gdb's notion of the inferior's terminal settings are consistent
+# with the values read from the inferior.
+
+proc compare_gdb_and_inferior_settings { t } {
+ global decimal
+ array set termios $t
+
+ gdb_test "info terminal" \
+ [multi_line "Inferior's terminal status .currently saved by GDB.:" \
+ "File descriptor flags = .*" \
+ "Process group = $decimal" \
+ "c_iflag = ${termios(c_iflag)}, c_oflag = ${termios(c_oflag)}," \
+ "c_cflag = ${termios(c_cflag)}, c_lflag = ${termios(c_lflag)}.*" ]
+}
-# While only native targets save terminal status, we still test
-# everywhere to make sure that the command doesn't misbehave.
if {[target_info gdb_protocol] == ""} {
- set term_re "Inferior's terminal status .currently saved by GDB.:.*"
+ # Record the initial terminal settings. Verify that GDB's version of the
+ # inferior's terminal settings is right.
+ with_test_prefix "initial" {
+ array set termios1 [read_term_settings_from_inferior]
+ compare_gdb_and_inferior_settings [array get termios1]
+ }
+
+ # Continue until after the inferior removes ECHO from its terminal settings.
+ gdb_continue_to_breakpoint "continue until after tcsetattr"
+
+ # After the inferior has changed its terminal settings, check that GDB's
+ # saved version reflects the new settings correctly.
+ with_test_prefix "post tcsetattr" {
+ array set termios2 [read_term_settings_from_inferior]
+ compare_gdb_and_inferior_settings [array get termios2]
+
+ # Make sure that the current settings are different than the initial
+ # settings... otherwise this test is meaningless.
+ gdb_assert {${termios1(c_lflag)} != ${termios2(c_lflag)}}
+ }
+
+ # Continue again...
+ gdb_continue_to_breakpoint "continue again"
+
+ # ... and verify again, to validate that when resuming, GDB restored the
+ # inferior's terminal settings correctly.
+ with_test_prefix "after last resume" {
+ array set termios3 [read_term_settings_from_inferior]
+ compare_gdb_and_inferior_settings [array get termios3]
+ gdb_assert {${termios2(c_iflag)} == ${termios3(c_iflag)}}
+ gdb_assert {${termios2(c_oflag)} == ${termios3(c_oflag)}}
+ gdb_assert {${termios2(c_cflag)} == ${termios3(c_cflag)}}
+ gdb_assert {${termios2(c_lflag)} == ${termios3(c_lflag)}}
+ }
} else {
- set term_re "No saved terminal information\\."
+ # While only native targets save terminal status, we still test
+ # that the command doesn't misbehave.
+ gdb_test "info terminal" "No saved terminal information\\." "info terminal at breakpoint"
}
-gdb_test "info terminal" $term_re "info terminal at breakpoint"
-
+delete_breakpoints
gdb_continue_to_end
# One last time after the program having exited.
gdb_test "info terminal" \
"No saved terminal information.*" \
- "test info terminal #2"
+ "test info terminal post-execution"