FreeChainXenon/binutils-gdb
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Suppress SIGTTOU when handling errors

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Calls to error () can cause SIGTTOU to send gdb to the background.

For example, on an Arm build:
  (gdb) b main
  Breakpoint 1 at 0x10774: file /build/gdb/testsuite/../../../src/binutils-gdb/gdb/testsuite/gdb.base/watchpoint.c, line 174.
  (gdb) r
  Starting program: /build/gdb/testsuite/outputs/gdb.base/watchpoint/watchpoint

  [1]+  Stopped                 ../gdb ./outputs/gdb.base/watchpoint/watchpoint
  localhost$ fg
  ../gdb ./outputs/gdb.base/watchpoint/watchpoint
  Cannot parse expression `.L1199 4@r4'.
  warning: Probes-based dynamic linker interface failed.
  Reverting to original interface.

The SIGTTOU is raised whilst inside a syscall during the call to tcdrain.
Fix is to use scoped_ignore_sigttou to ensure SIGTTOU is blocked.

In addition fix include comments - job_control is not included via terminal.h

gdb/ChangeLog:

	* event-top.c: Remove include comment.
	* inflow.c (class scoped_ignore_sigttou): Move from here...
	* inflow.h (class scoped_ignore_sigttou): ...to here.
	* ser-unix.c (hardwire_drain_output): Block SIGTTOU during drain.
	* top.c:  Remove include comment.
This commit is contained in:
Alan Hayward 2019-05-28 10:07:54 +01:00
parent 0f4a61b420
commit 766f883622
6 changed files with 45 additions and 31 deletions
Download patch file Download diff file Expand all files Collapse all files

8
gdb/ChangeLog
View file

@ -1,3 +1,11 @@
2019-05-28 Alan Hayward <alan.hayward@arm.com>
* event-top.c: Remove include comment.
* inflow.c (class scoped_ignore_sigttou): Move from here...
* inflow.h (class scoped_ignore_sigttou): ...to here.
* ser-unix.c (hardwire_drain_output): Block SIGTTOU during drain.
* top.c: Remove include comment.
2019-05-27 Tom Tromey <tom@tromey.com>
* NEWS: Fix typo.

2
gdb/event-top.c
View file

@ -24,7 +24,7 @@
#include "inferior.h"
#include "infrun.h"
#include "target.h"
#include "terminal.h" /* for job_control */
#include "terminal.h"
#include "event-loop.h"
#include "event-top.h"
#include "interps.h"

29
gdb/inflow.c
View file

@ -106,35 +106,6 @@ static serial_ttystate initial_gdb_ttystate;
static struct terminal_info *get_inflow_inferior_data (struct inferior *);
/* RAII class used to ignore SIGTTOU in a scope. */
class scoped_ignore_sigttou
{
public:
scoped_ignore_sigttou ()
{
#ifdef SIGTTOU
if (job_control)
m_osigttou = signal (SIGTTOU, SIG_IGN);
#endif
}
~scoped_ignore_sigttou ()
{
#ifdef SIGTTOU
if (job_control)
signal (SIGTTOU, m_osigttou);
#endif
}
DISABLE_COPY_AND_ASSIGN (scoped_ignore_sigttou);
private:
#ifdef SIGTTOU
sighandler_t m_osigttou = NULL;
#endif
};
/* While the inferior is running, we want SIGINT and SIGQUIT to go to the
inferior only. If we have job control, that takes care of it. If not,
we save our handlers in these two variables and set SIGINT and SIGQUIT

31
gdb/inflow.h
View file

@ -21,5 +21,36 @@
#define INFLOW_H
#include <unistd.h>
#include <signal.h>
#include "common/job-control.h"
/* RAII class used to ignore SIGTTOU in a scope. */
class scoped_ignore_sigttou
{
public:
scoped_ignore_sigttou ()
{
#ifdef SIGTTOU
if (job_control)
m_osigttou = signal (SIGTTOU, SIG_IGN);
#endif
}
~scoped_ignore_sigttou ()
{
#ifdef SIGTTOU
if (job_control)
signal (SIGTTOU, m_osigttou);
#endif
}
DISABLE_COPY_AND_ASSIGN (scoped_ignore_sigttou);
private:
#ifdef SIGTTOU
sighandler_t m_osigttou = NULL;
#endif
};
#endif /* inflow.h */

4
gdb/ser-unix.c
View file

@ -32,6 +32,7 @@
#include "gdbcmd.h"
#include "common/filestuff.h"
#include <termios.h>
#include "inflow.h"
struct hardwire_ttystate
{
@ -164,6 +165,9 @@ hardwire_print_tty_state (struct serial *scb,
static int
hardwire_drain_output (struct serial *scb)
{
/* Ignore SIGTTOU which may occur during the drain. */
scoped_ignore_sigttou ignore_sigttou;
return tcdrain (scb->fd);
}

2
gdb/top.c
View file

@ -34,7 +34,7 @@
#include "expression.h"
#include "value.h"
#include "language.h"
#include "terminal.h" /* For job_control. */
#include "terminal.h"
#include "common/job-control.h"
#include "annotate.h"
#include "completer.h"