Adding upstream version 3.4.23.upstream/3.4.23upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 275 insertions, 0 deletions

diff --git a/src/master/master_sig.c b/src/master/master_sig.c
new file mode 100644
index 0000000..db5e39d
--- /dev/null
+++ b/src/master/master_sig.c
@@ -0,0 +1,275 @@
+/*++
+/* NAME
+/*	master_sig 3
+/* SUMMARY
+/*	Postfix master - signal processing
+/* SYNOPSIS
+/*	#include "master.h"
+/*
+/*	int	master_gotsighup;
+/*	int	master_gotsigchld;
+/*
+/*	int	master_sigsetup()
+/* DESCRIPTION
+/*	This module implements the master process signal handling interface.
+/*
+/*	master_gotsighup (master_gotsigchld) is set to SIGHUP (SIGCHLD)
+/*	when the process receives a hangup (child death) signal.
+/*
+/*	master_sigsetup() enables processing of hangup and child death signals.
+/*	Receipt of SIGINT, SIGQUIT, SIGSEGV, SIGILL, or SIGTERM
+/*	is interpreted as a request for termination.  Child processes are
+/*	notified of the master\'s demise by sending them a SIGTERM signal.
+/* DIAGNOSTICS
+/* BUGS
+/*	Need a way to register cleanup actions.
+/* SEE ALSO
+/* LICENSE
+/* .ad
+/* .fi
+/*	The Secure Mailer license must be distributed with this software.
+/* AUTHOR(S)
+/*	Wietse Venema
+/*	IBM T.J. Watson Research
+/*	P.O. Box 704
+/*	Yorktown Heights, NY 10598, USA
+/*
+/*	Wietse Venema
+/*	Google, Inc.
+/*	111 8th Avenue
+/*	New York, NY 10011, USA
+/*--*/
+
+/* System libraries. */
+
+#include <sys_defs.h>
+#include <signal.h>
+#include <unistd.h>
+
+/* Utility library. */
+
+#include <msg.h>
+#include <posix_signals.h>
+#include <killme_after.h>
+
+/* Application-specific. */
+
+#include "master.h"
+
+#ifdef USE_SIG_RETURN
+#include <sys/syscall.h>
+#undef USE_SIG_PIPE
+#else
+#define USE_SIG_PIPE
+#endif
+
+/* Local stuff. */
+
+#ifdef USE_SIG_PIPE
+#include <errno.h>
+#include <fcntl.h>
+#include <iostuff.h>
+#include <events.h>
+
+int     master_sig_pipe[2];
+
+#define SIG_PIPE_WRITE_FD master_sig_pipe[1]
+#define SIG_PIPE_READ_FD master_sig_pipe[0]
+#endif
+
+int     master_gotsigchld;
+int     master_gotsighup;
+
+#ifdef USE_SIG_RETURN
+
+/* master_sighup - register arrival of hangup signal */
+
+static void master_sighup(int sig)
+{
+
+    /*
+     * WARNING WARNING WARNING.
+     * 
+     * This code runs at unpredictable moments, as a signal handler. Don't put
+     * any code here other than for setting a global flag.
+     */
+    master_gotsighup = sig;
+}
+
+/* master_sigchld - register arrival of child death signal */
+
+static void master_sigchld(int sig, int code, struct sigcontext * scp)
+{
+
+    /*
+     * WARNING WARNING WARNING.
+     * 
+     * This code runs at unpredictable moments, as a signal handler. Don't put
+     * any code here other than for setting a global flag, or code that is
+     * intended to be run within a signal handler.
+     */
+    master_gotsigchld = sig;
+    if (scp != NULL && scp->sc_syscall == SYS_select) {
+	scp->sc_syscall_action = SIG_RETURN;
+#ifndef SA_RESTART
+    } else if (scp != NULL) {
+	scp->sc_syscall_action = SIG_RESTART;
+#endif
+    }
+}
+
+#else
+
+/* master_sighup - register arrival of hangup signal */
+
+static void master_sighup(int sig)
+{
+    int     saved_errno = errno;
+
+    /*
+     * WARNING WARNING WARNING.
+     * 
+     * This code runs at unpredictable moments, as a signal handler. Don't put
+     * any code here other than for setting a global flag, or code that is
+     * intended to be run within a signal handler. Restore errno in case we
+     * are interrupting the epilog of a failed system call.
+     */
+    master_gotsighup = sig;
+    if (write(SIG_PIPE_WRITE_FD, "", 1) != 1)
+	msg_warn("write to SIG_PIPE_WRITE_FD failed: %m");
+    errno = saved_errno;
+}
+
+/* master_sigchld - force wakeup from select() */
+
+static void master_sigchld(int unused_sig)
+{
+    int     saved_errno = errno;
+
+    /*
+     * WARNING WARNING WARNING.
+     * 
+     * This code runs at unpredictable moments, as a signal handler. Don't put
+     * any code here other than for setting a global flag, or code that is
+     * intended to be run within a signal handler. Restore errno in case we
+     * are interrupting the epilog of a failed system call.
+     */
+    master_gotsigchld = 1;
+    if (write(SIG_PIPE_WRITE_FD, "", 1) != 1)
+	msg_warn("write to SIG_PIPE_WRITE_FD failed: %m");
+    errno = saved_errno;
+}
+
+/* master_sig_event - called upon return from select() */
+
+static void master_sig_event(int unused_event, void *unused_context)
+{
+    char    c[1];
+
+    while (read(SIG_PIPE_READ_FD, c, 1) > 0)
+	 /* void */ ;
+}
+
+#endif
+
+/* master_sigdeath - die, women and children first */
+
+static void master_sigdeath(int sig)
+{
+    const char *myname = "master_sigdeath";
+    struct sigaction action;
+    pid_t   pid = getpid();
+
+    /*
+     * Set alarm clock here for suicide after 5s.
+     */
+    killme_after(5);
+
+    /*
+     * Terminate all processes in our process group, except ourselves.
+     */
+    sigemptyset(&action.sa_mask);
+    action.sa_flags = 0;
+    action.sa_handler = SIG_IGN;
+    if (sigaction(SIGTERM, &action, (struct sigaction *) 0) < 0)
+	msg_fatal("%s: sigaction: %m", myname);
+    if (kill(-pid, SIGTERM) < 0)
+	msg_fatal("%s: kill process group: %m", myname);
+
+    /*
+     * XXX We're running from a signal handler, and should not call complex
+     * routines at all, but it would be even worse to silently terminate
+     * without informing the sysadmin. For this reason, msg(3) was made safe
+     * for usage by signal handlers that terminate the process.
+     */
+    msg_info("terminating on signal %d", sig);
+
+    /*
+     * Undocumented: when a process runs with PID 1, Linux won't deliver a
+     * signal unless the process specifies a handler (i.e. SIG_DFL is treated
+     * as SIG_IGN).
+     */
+    if (init_mode)
+	/* Don't call exit() from a signal handler. */
+	_exit(0);
+
+    /*
+     * Deliver the signal to ourselves and clean up. XXX We're running as a
+     * signal handler and really should not be doing complicated things...
+     */
+    sigemptyset(&action.sa_mask);
+    action.sa_flags = 0;
+    action.sa_handler = SIG_DFL;
+    if (sigaction(sig, &action, (struct sigaction *) 0) < 0)
+	msg_fatal("%s: sigaction: %m", myname);
+    if (kill(pid, sig) < 0)
+	msg_fatal("%s: kill myself: %m", myname);
+}
+
+/* master_sigsetup - set up signal handlers */
+
+void    master_sigsetup(void)
+{
+    const char *myname = "master_sigsetup";
+    struct sigaction action;
+    static int sigs[] = {
+	SIGINT, SIGQUIT, SIGILL, SIGBUS, SIGSEGV, SIGTERM,
+    };
+    unsigned i;
+
+    sigemptyset(&action.sa_mask);
+    action.sa_flags = 0;
+
+    /*
+     * Prepare to kill our children when we receive any of the above signals.
+     */
+    action.sa_handler = master_sigdeath;
+    for (i = 0; i < sizeof(sigs) / sizeof(sigs[0]); i++)
+	if (sigaction(sigs[i], &action, (struct sigaction *) 0) < 0)
+	    msg_fatal("%s: sigaction(%d): %m", myname, sigs[i]);
+
+#ifdef USE_SIG_PIPE
+    if (pipe(master_sig_pipe))
+	msg_fatal("pipe: %m");
+    non_blocking(SIG_PIPE_WRITE_FD, NON_BLOCKING);
+    non_blocking(SIG_PIPE_READ_FD, NON_BLOCKING);
+    close_on_exec(SIG_PIPE_WRITE_FD, CLOSE_ON_EXEC);
+    close_on_exec(SIG_PIPE_READ_FD, CLOSE_ON_EXEC);
+    event_enable_read(SIG_PIPE_READ_FD, master_sig_event, (void *) 0);
+#endif
+
+    /*
+     * Intercept SIGHUP (re-read config file) and SIGCHLD (child exit).
+     */
+#ifdef SA_RESTART
+    action.sa_flags |= SA_RESTART;
+#endif
+    action.sa_handler = master_sighup;
+    if (sigaction(SIGHUP, &action, (struct sigaction *) 0) < 0)
+	msg_fatal("%s: sigaction(%d): %m", myname, SIGHUP);
+
+    action.sa_flags |= SA_NOCLDSTOP;
+    action.sa_handler = master_sigchld;
+    if (sigaction(SIGCHLD, &action, (struct sigaction *) 0) < 0)
+	msg_fatal("%s: sigaction(%d): %m", myname, SIGCHLD);
+}