New module 'sigpipe-die'.

[gnulib.git] / lib / sigpipe-die.c

diff --git a/lib/sigpipe-die.c b/lib/sigpipe-die.c
new file mode 100644 (file)
index 0000000..bb3c8b0
--- /dev/null
+++ b/lib/sigpipe-die.c
@@ -0,0 +1,82 @@
+/* Report a SIGPIPE signal and exit.
+   Copyright (C) 2008 Free Software Foundation, Inc.
+
+   This program is free software: you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
+
+/* Written by Bruno Haible <bruno@clisp.org>, 2008.  */
+
+#include <config.h>
+
+/* Specification.  */
+#include "sigpipe-die.h"
+
+#include <signal.h>
+#include <stdlib.h>
+
+#include "error.h"
+#include "exitfail.h"
+
+#include "gettext.h"
+#define _(msgid) gettext (msgid)
+
+void
+sigpipe_die (void)
+{
+  error (exit_failure, 0, "%s",
+        _("error writing to a closed pipe or socket"));
+
+  /* Ensure that this function really does not return.  */
+  abort ();
+}
+
+static void (*prepare_die_hook) (void);
+
+/* This is the signal handler for SIGPIPE.  It is invoked synchronously,
+   therefore it can make library calls to malloc(), gettext(), exit() etc. -
+   although in general it is undefined behaviour to do such calls from
+   within signal handlers.  */
+static void
+sigpipe_die_handler (int sig)
+{
+  if (prepare_die_hook != NULL)
+    (*prepare_die_hook) ();
+  sigpipe_die ();
+}
+
+void
+install_sigpipe_die_handler (void (*prepare_die) (void))
+{
+  prepare_die_hook = prepare_die;
+
+  /* Install the handler.  */
+  {
+    struct sigaction action;
+
+    action.sa_handler = sigpipe_die_handler;
+    action.sa_flags = 0;
+    sigemptyset (&action.sa_mask);
+    if (sigaction (SIGPIPE, &action, NULL) >= 0)
+      {
+       /* Unblock the signal (just in case).  This is needed because if the
+          signal was blocked in the parent process, it is also blocked in
+          this process: the mask of blocked signals is inherited across
+          fork/exec (except for SIGCHLD).  */
+       sigset_t sigpipe_set;
+
+       sigemptyset (&sigpipe_set);
+       sigaddset (&sigpipe_set, SIGPIPE);
+       sigprocmask (SIG_UNBLOCK, &sigpipe_set, NULL);
+      }
+  }
+}