fix signal handling (#1073698)
This commit is contained in:
Nils Philippsen
parent
e92b2b861f
commit
59a0b0a864
220
xsane-0.999-signal-handling.patch
Normal file
220
xsane-0.999-signal-handling.patch
Normal file
@ -0,0 +1,220 @@
|
||||
From 54a700c45c81f1ffff5f3dfcecb3929143e31d48 Mon Sep 17 00:00:00 2001
|
||||
From: Nils Philippsen <nils@redhat.com>
|
||||
Date: Wed, 19 Mar 2014 13:23:16 +0100
|
||||
Subject: [PATCH] patch: signal-handling
|
||||
|
||||
Squashed commit of the following:
|
||||
|
||||
commit 2b629e1d9c60dcf26defe6d05b515611874db270
|
||||
Author: Nils Philippsen <nils@redhat.com>
|
||||
Date: Thu Mar 13 13:38:12 2014 +0100
|
||||
|
||||
separate signal handlers in top and bottom half
|
||||
|
||||
This is to avoid race-conditions occurring when a signal is received
|
||||
while the signal handler is not yet finished. It also avoids calling
|
||||
non-reentrant functions from a signal handler. The top half (the real
|
||||
signal handler) just writes a character into a pipe which gets picked up
|
||||
and serviced by the bottom half from the normal event loop, this
|
||||
serializes things and makes use of non-reentrant functions safe.
|
||||
---
|
||||
src/xsane.c | 146 +++++++++++++++++++++++++++++++++++++++++++++++++++++-------
|
||||
1 file changed, 131 insertions(+), 15 deletions(-)
|
||||
|
||||
diff --git a/src/xsane.c b/src/xsane.c
|
||||
index eee76ff..02b4da4 100644
|
||||
--- a/src/xsane.c
|
||||
+++ b/src/xsane.c
|
||||
@@ -47,6 +47,7 @@
|
||||
#endif
|
||||
|
||||
#include <sys/wait.h>
|
||||
+#include <glib-unix.h>
|
||||
|
||||
#include <stdarg.h>
|
||||
|
||||
@@ -121,6 +122,7 @@ static const Preferences_medium_t pref_default_medium[]=
|
||||
|
||||
int DBG_LEVEL = 0;
|
||||
static guint xsane_resolution_timer = 0;
|
||||
+static int xsane_signal_pipe[2];
|
||||
|
||||
/* ---------------------------------------------------------------------------------------------------------------------- */
|
||||
|
||||
@@ -161,8 +163,11 @@ void xsane_pref_save(void);
|
||||
static int xsane_pref_restore(void);
|
||||
static void xsane_pref_save_media(void);
|
||||
static void xsane_pref_restore_media(void);
|
||||
-static RETSIGTYPE xsane_quit_handler(int signal);
|
||||
-static RETSIGTYPE xsane_sigchld_handler(int signal);
|
||||
+static RETSIGTYPE xsane_signal_handler_top_half(int signal);
|
||||
+static gboolean xsane_signal_handler_bottom_half(gint fd,
|
||||
+ GIOCondition condition,
|
||||
+ gpointer user_data);
|
||||
+static void xsane_sigchld_handler(void);
|
||||
static void xsane_quit(void);
|
||||
static void xsane_exit(void);
|
||||
static gint xsane_standard_option_win_delete(GtkWidget *widget, gpointer data);
|
||||
@@ -2296,16 +2301,119 @@ static void xsane_pref_restore_media(void)
|
||||
|
||||
/* ---------------------------------------------------------------------------------------------------------------------- */
|
||||
|
||||
-static RETSIGTYPE xsane_quit_handler(int signal)
|
||||
+static RETSIGTYPE xsane_signal_handler_top_half(int signal)
|
||||
{
|
||||
- DBG(DBG_proc, "xsane_quit_handler\n");
|
||||
+ const char *msg_func = "xsane_signal_handler_top_half(): ";
|
||||
+ const char *msg_short_write = "Short write() while processing signal.\n";
|
||||
+ const char *msg_err = "Error during write().\n";
|
||||
+ char sig_char;
|
||||
+ ssize_t written;
|
||||
+ int errno_saved = errno;
|
||||
|
||||
- xsane_quit();
|
||||
+ switch (signal)
|
||||
+ {
|
||||
+ case SIGTERM:
|
||||
+ sig_char = 't';
|
||||
+ break;
|
||||
+ case SIGINT:
|
||||
+ sig_char = 'i';
|
||||
+ break;
|
||||
+ case SIGHUP:
|
||||
+ sig_char = 'h';
|
||||
+ break;
|
||||
+ case SIGCHLD:
|
||||
+ sig_char = 'c';
|
||||
+ break;
|
||||
+ default:
|
||||
+ sig_char = '?';
|
||||
+ break;
|
||||
+ }
|
||||
+
|
||||
+ if ((written = write(xsane_signal_pipe[1], &sig_char, 1)) <= 0)
|
||||
+ {
|
||||
+ /* At this point, all bets are off. Salvage what we can. */
|
||||
+
|
||||
+ const char *msg = (written == 0) ? msg_short_write : msg_err;
|
||||
+
|
||||
+ if ((write(STDERR_FILENO, msg_func, strlen(msg_func)) < 0) ||
|
||||
+ (write(STDERR_FILENO, msg, strlen(msg)) < 0))
|
||||
+ {
|
||||
+ /* This is really a no-op, but at this point it doesn't really matter
|
||||
+ * anymore if the writes succeeded or not. */
|
||||
+ goto bail_out;
|
||||
+ }
|
||||
+
|
||||
+bail_out:
|
||||
+ /* Ignore SIGCHLD errors, zombie processes don't hurt that much. */
|
||||
+ if (signal != SIGCHLD)
|
||||
+ {
|
||||
+ struct SIGACTION act;
|
||||
+ memset(&act, 0, sizeof(act));
|
||||
+ act.sa_handler = SIG_DFL;
|
||||
+ sigaction(signal, &act, NULL);
|
||||
+ raise(signal);
|
||||
+ }
|
||||
+ }
|
||||
+
|
||||
+ errno = errno_saved;
|
||||
+}
|
||||
+
|
||||
+static gboolean xsane_signal_handler_bottom_half(gint fd,
|
||||
+ GIOCondition condition,
|
||||
+ gpointer user_data)
|
||||
+{
|
||||
+ char sig_char;
|
||||
+ ssize_t readlen;
|
||||
+
|
||||
+ DBG(DBG_proc, "xsane_signal_handler_bottom_half\n");
|
||||
+
|
||||
+ while ((readlen = read(xsane_signal_pipe[0], &sig_char, 1)) != 0)
|
||||
+ {
|
||||
+ if (readlen < 0)
|
||||
+ {
|
||||
+ if (errno == EINTR)
|
||||
+ {
|
||||
+ /* if interrupted by signal, just repeat reading */
|
||||
+ continue;
|
||||
+ }
|
||||
+ else
|
||||
+ {
|
||||
+ break;
|
||||
+ }
|
||||
+ }
|
||||
+
|
||||
+ switch (sig_char)
|
||||
+ {
|
||||
+ case 't':
|
||||
+ case 'i':
|
||||
+ case 'h':
|
||||
+ xsane_quit();
|
||||
+ break;
|
||||
+ case 'c':
|
||||
+ xsane_sigchld_handler();
|
||||
+ break;
|
||||
+ default:
|
||||
+ DBG(DBG_error,
|
||||
+ "Don't know how to cope with character-encoded signal: '%c'\n",
|
||||
+ sig_char);
|
||||
+ break;
|
||||
+ }
|
||||
+ }
|
||||
+
|
||||
+ /* previous invocation might have read more than it should, so ignore
|
||||
+ * EGAIN/EWOULDBLOCK */
|
||||
+ if (readlen < 0 && errno != EAGAIN && errno != EWOULDBLOCK)
|
||||
+ {
|
||||
+ DBG(DBG_error, "Error while reading from pipe: %d '%s'\n", errno,
|
||||
+ strerror(errno));
|
||||
+ }
|
||||
+
|
||||
+ return TRUE;
|
||||
}
|
||||
|
||||
/* ---------------------------------------------------------------------------------------------------------------------- */
|
||||
|
||||
-static RETSIGTYPE xsane_sigchld_handler(int signal)
|
||||
+static void xsane_sigchld_handler(void)
|
||||
{
|
||||
int status;
|
||||
XsaneChildprocess **childprocess_listptr = &xsane.childprocess_list;
|
||||
@@ -6062,18 +6170,26 @@ void xsane_interface(int argc, char **argv)
|
||||
}
|
||||
}
|
||||
|
||||
+ if (!g_unix_open_pipe(xsane_signal_pipe, FD_CLOEXEC, NULL) ||
|
||||
+ fcntl(xsane_signal_pipe[0], F_SETFL, O_NONBLOCK, 1) ||
|
||||
+ fcntl(xsane_signal_pipe[1], F_SETFL, O_NONBLOCK, 1) ||
|
||||
+ !g_unix_fd_add(xsane_signal_pipe[0], G_IO_IN | G_IO_PRI,
|
||||
+ xsane_signal_handler_bottom_half, NULL))
|
||||
+ {
|
||||
+ DBG(DBG_error,
|
||||
+ "Couldn't create signal handling pipe, set flags on it or install\n"
|
||||
+ "bottom half of handler.\n");
|
||||
+ exit(1);
|
||||
+ }
|
||||
+
|
||||
/* define SIGTERM, SIGINT, SIGHUP-handler to make sure that e.g. all temporary files are deleted */
|
||||
/* when xsane gets such a signal */
|
||||
memset(&act, 0, sizeof(act));
|
||||
- act.sa_handler = xsane_quit_handler;
|
||||
- sigaction(SIGTERM, &act, 0);
|
||||
- sigaction(SIGINT, &act, 0);
|
||||
- sigaction(SIGHUP, &act, 0);
|
||||
-
|
||||
- /* add a signal handler that cleans up zombie child processes */
|
||||
- memset(&act, 0, sizeof(act));
|
||||
- act.sa_handler = xsane_sigchld_handler;
|
||||
- sigaction(SIGCHLD, &act, 0);
|
||||
+ act.sa_handler = xsane_signal_handler_top_half;
|
||||
+ sigaction(SIGTERM, &act, NULL);
|
||||
+ sigaction(SIGINT, &act, NULL);
|
||||
+ sigaction(SIGHUP, &act, NULL);
|
||||
+ sigaction(SIGCHLD, &act, NULL);
|
||||
|
||||
gtk_main();
|
||||
sane_exit();
|
||||
--
|
||||
1.8.5.3
|
||||
|
||||
@ -61,6 +61,9 @@ Patch11: xsane-0.999-pdf-no-high-bpp.patch
|
||||
# build against lcms 2.x
|
||||
# submitted to upstream (Oliver Rauch) via email, 2013-09-23
|
||||
Patch12: xsane-0.999-lcms2.patch
|
||||
# fix signal handling (#1073698)
|
||||
# submitted to upstream (Oliver Rauch) via email, 2014-03-19
|
||||
Patch13: xsane-0.999-signal-handling.patch
|
||||
# autoconf-generated files
|
||||
Patch100: xsane-0.999-7-autoconf.patch.bz2
|
||||
License: GPLv2+
|
||||
@ -126,6 +129,7 @@ done
|
||||
%patch10 -p1 -b .man-page
|
||||
%patch11 -p1 -b .pdf-no-high-bpp
|
||||
%patch12 -p1 -b .lcms2
|
||||
%patch13 -p1 -b .signal-handling
|
||||
|
||||
%patch100 -p1 -b .autoconf
|
||||
|
||||
@ -230,6 +234,9 @@ fi
|
||||
%{_datadir}/sane/xsane
|
||||
|
||||
%changelog
|
||||
* Wed Mar 19 2014 Nils Philippsen <nils@redhat.com>
|
||||
- fix signal handling (#1073698)
|
||||
|
||||
* Mon Sep 23 2013 Nils Philippsen <nils@redhat.com> - 0.999-7
|
||||
- get rid of ancient compat cruft
|
||||
- build against lcms2
|
||||
|
||||
Loading…
Reference in New Issue
Block a user