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authorPedro Alves <palves@redhat.com>2016-06-01 16:34:49 +0100
committerPedro Alves <palves@redhat.com>2016-06-01 16:34:49 +0100
commitbb7c96deb1a14ef7e8b51d5339a65a8064515c78 (patch)
treeed1a03c853ab2d2ec25cf228ec5bf8f705bcfa37
parent315f180f2f0a59af561180e4ed9387f4c7bada78 (diff)
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gdb/remote-fileio.c: Eliminate custom SIGINT signal handler
... and fix Ctrl-C races. The current remote-fileio.c SIGINT/EINTR code can lose Ctrl-C -- there's a period where SIG_IGN is installed as signal handler, for example. Since: - remote.c no longer installs a custom SIGINT handler; - The current remote-fileio.c SIGINT handler is basically the same as the default SIGINT handler (event-top.c:handle_sigint), in principle, except that instead of setting the quit flag, it sets a separate flag. I think we should be able to completely remove the remote-fileio.c SIGINT handler, and centralize on the quit flag, thus fixing the Ctrl-C race. gdb/ChangeLog: yyyy-mm-dd Pedro Alves <palves@redhat.com> * remote-fileio.c (remote_fio_ctrl_c_flag, remote_fio_sa) (remote_fio_osa) (remote_fio_ofunc, remote_fileio_sig_init, remote_fileio_sig_set) (remote_fileio_sig_exit, remote_fileio_ctrl_c_signal_handler): Delete. (remote_fileio_o_quit_handler): New global. (remote_fileio_quit_handler): New function. (remote_fileio_reply): Check the quit flag instead of the custom 'remote_fio_ctrl_c_flag' flag. Restore the quit handler instead of changing the SIGINT handler. (do_remote_fileio_request): Override the quit handler instead of changing the SIGINT handler.
-rw-r--r--gdb/ChangeLog15
-rw-r--r--gdb/remote-fileio.c80
2 files changed, 35 insertions, 60 deletions
diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index 9d08c67..18261a7 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,3 +1,18 @@
+2016-06-01 Pedro Alves <palves@redhat.com>
+
+ * remote-fileio.c (remote_fio_ctrl_c_flag, remote_fio_sa)
+ (remote_fio_osa)
+ (remote_fio_ofunc, remote_fileio_sig_init, remote_fileio_sig_set)
+ (remote_fileio_sig_exit, remote_fileio_ctrl_c_signal_handler):
+ Delete.
+ (remote_fileio_o_quit_handler): New global.
+ (remote_fileio_quit_handler): New function.
+ (remote_fileio_reply): Check the quit flag instead of the custom
+ 'remote_fio_ctrl_c_flag' flag. Restore the quit handler instead
+ of changing the SIGINT handler.
+ (do_remote_fileio_request): Override the quit handler instead of
+ changing the SIGINT handler.
+
2016-06-01 Nick Clifton <nickc@redhat.com>
* common/common-utils.c (xmalloc_failed): New function. Provided
diff --git a/gdb/remote-fileio.c b/gdb/remote-fileio.c
index 29c5ca3..93121aa 100644
--- a/gdb/remote-fileio.c
+++ b/gdb/remote-fileio.c
@@ -298,66 +298,25 @@ remote_fileio_to_fio_timeval (struct timeval *tv, struct fio_timeval *ftv)
remote_fileio_to_fio_long (tv->tv_usec, ftv->ftv_usec);
}
-static int remote_fio_ctrl_c_flag = 0;
+/* The quit handler originally installed. */
+static quit_handler_ftype *remote_fileio_o_quit_handler;
-#if defined (HAVE_SIGACTION) && defined (SA_RESTART)
-static struct sigaction remote_fio_sa;
-static struct sigaction remote_fio_osa;
-#else
-static void (*remote_fio_ofunc)(int);
-#endif
+/* What to do on a QUIT call while handling a file I/O request. We
+ throw a quit exception, which is caught by remote_fileio_request
+ and translated to an EINTR reply back to the target. */
static void
-remote_fileio_sig_init (void)
+remote_fileio_quit_handler (void)
{
-#if defined (HAVE_SIGACTION) && defined (SA_RESTART)
- remote_fio_sa.sa_handler = SIG_IGN;
- sigemptyset (&remote_fio_sa.sa_mask);
- remote_fio_sa.sa_flags = 0;
- sigaction (SIGINT, &remote_fio_sa, &remote_fio_osa);
-#else
- remote_fio_ofunc = signal (SIGINT, SIG_IGN);
-#endif
-}
-
-static void
-remote_fileio_sig_set (void (*sigint_func)(int))
-{
-#if defined (HAVE_SIGACTION) && defined (SA_RESTART)
- remote_fio_sa.sa_handler = sigint_func;
- sigemptyset (&remote_fio_sa.sa_mask);
- remote_fio_sa.sa_flags = 0;
- sigaction (SIGINT, &remote_fio_sa, NULL);
-#else
- signal (SIGINT, sigint_func);
-#endif
-}
-
-static void
-remote_fileio_sig_exit (void)
-{
-#if defined (HAVE_SIGACTION) && defined (SA_RESTART)
- sigaction (SIGINT, &remote_fio_osa, NULL);
-#else
- signal (SIGINT, remote_fio_ofunc);
-#endif
-}
-
-static void
-remote_fileio_ctrl_c_signal_handler (int signo)
-{
- remote_fileio_sig_set (remote_fileio_ctrl_c_signal_handler);
- remote_fio_ctrl_c_flag = 1;
- /* Wake up interruptible_select. */
- quit_serial_event_set ();
+ quit ();
}
static void
remote_fileio_reply (int retcode, int error)
{
char buf[32];
+ int ctrl_c = check_quit_flag ();
- remote_fileio_sig_set (SIG_IGN);
strcpy (buf, "F");
if (retcode < 0)
{
@@ -365,9 +324,9 @@ remote_fileio_reply (int retcode, int error)
retcode = -retcode;
}
sprintf (buf + strlen (buf), "%x", retcode);
- if (error || remote_fio_ctrl_c_flag)
+ if (error || ctrl_c)
{
- if (error && remote_fio_ctrl_c_flag)
+ if (error && ctrl_c)
error = FILEIO_EINTR;
if (error < 0)
{
@@ -375,11 +334,10 @@ remote_fileio_reply (int retcode, int error)
error = -error;
}
sprintf (buf + strlen (buf), ",%x", error);
- if (remote_fio_ctrl_c_flag)
+ if (ctrl_c)
strcat (buf, ",C");
}
- remote_fio_ctrl_c_flag = 0;
- remote_fileio_sig_set (remote_fileio_ctrl_c_signal_handler);
+ quit_handler = remote_fileio_o_quit_handler;
putpkt (buf);
}
@@ -1166,7 +1124,7 @@ do_remote_fileio_request (struct ui_out *uiout, void *buf_arg)
char *c;
int idx;
- remote_fileio_sig_set (remote_fileio_ctrl_c_signal_handler);
+ quit_handler = remote_fileio_quit_handler;
c = strchr (++buf, ',');
if (c)
@@ -1213,20 +1171,22 @@ remote_fileio_request (char *buf, int ctrlc_pending_p)
{
int ex;
- remote_fileio_sig_init ();
+ /* Save the previous quit handler, so we can restore it. No need
+ for a cleanup since we catch all exceptions below. Note that the
+ quit handler is also restored by remote_fileio_reply just before
+ pushing a packet. */
+ remote_fileio_o_quit_handler = quit_handler;
if (ctrlc_pending_p)
{
/* If the target hasn't responded to the Ctrl-C sent
asynchronously earlier, take this opportunity to send the
Ctrl-C synchronously. */
- remote_fio_ctrl_c_flag = 1;
+ set_quit_flag ();
remote_fileio_reply (-1, FILEIO_EINTR);
}
else
{
- remote_fio_ctrl_c_flag = 0;
-
ex = catch_exceptions (current_uiout,
do_remote_fileio_request, (void *)buf,
RETURN_MASK_ALL);
@@ -1243,7 +1203,7 @@ remote_fileio_request (char *buf, int ctrlc_pending_p)
}
}
- remote_fileio_sig_exit ();
+ quit_handler = remote_fileio_o_quit_handler;
}