[binutils-gdb/gdb-8.3-branch] Suppress SIGTTOU when handling errors

[Tom de Vries <vries at sourceware dot org>]

https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;h=8ac39635f6f0b7019f4a474f995e94d447fe8d38

commit 8ac39635f6f0b7019f4a474f995e94d447fe8d38
Author: Alan Hayward <alan.hayward@arm.com>
Date:   Wed Aug 7 18:23:49 2019 +0200

    Suppress SIGTTOU when handling errors
    
    [ Backport of commit 766f883622. ]
    
    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.

Diff:
---
 gdb/ChangeLog   |  8 ++++++++
 gdb/event-top.c |  2 +-
 gdb/inflow.c    | 29 -----------------------------
 gdb/inflow.h    | 31 +++++++++++++++++++++++++++++++
 gdb/ser-unix.c  |  4 ++++
 gdb/top.c       |  2 +-
 6 files changed, 45 insertions(+), 31 deletions(-)

diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index f101a27..c8ddcf6 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -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.
+
 2019-08-04  Alan Hayward  <alan.hayward@arm.com>
 
 	* symfile.c (symbol_file_command): Call solib_create_inferior_hook.
diff --git a/gdb/event-top.c b/gdb/event-top.c
index fb5d51c..e077e29 100644
--- a/gdb/event-top.c
+++ b/gdb/event-top.c
@@ -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"
diff --git a/gdb/inflow.c b/gdb/inflow.c
index b715113..c1f2693 100644
--- a/gdb/inflow.c
+++ b/gdb/inflow.c
@@ -103,35 +103,6 @@ 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
diff --git a/gdb/inflow.h b/gdb/inflow.h
index c32aa14..5dd5c37 100644
--- a/gdb/inflow.h
+++ b/gdb/inflow.h
@@ -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 */
diff --git a/gdb/ser-unix.c b/gdb/ser-unix.c
index 5a9965b..3492619 100644
--- a/gdb/ser-unix.c
+++ b/gdb/ser-unix.c
@@ -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);
 }
 
diff --git a/gdb/top.c b/gdb/top.c
index acc6720..00e0791 100644
--- a/gdb/top.c
+++ b/gdb/top.c
@@ -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"