Adding upstream version 3.4.23.upstream/3.4.23upstream

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

1 files changed, 198 insertions, 0 deletions

diff --git a/src/master/master_status.c b/src/master/master_status.c
new file mode 100644
index 0000000..fb3bb73
--- /dev/null
+++ b/src/master/master_status.c
@@ -0,0 +1,198 @@
+/*++
+/* NAME
+/*	master_status 3
+/* SUMMARY
+/*	Postfix master - process child status reports
+/* SYNOPSIS
+/*	#include "master.h"
+/*
+/*	void	master_status_init(serv)
+/*	MASTER_SERV *serv;
+/*
+/*	void	master_status_cleanup(serv)
+/*	MASTER_SERV *serv;
+/* DESCRIPTION
+/*	This module reads and processes status reports from child processes.
+/*
+/*	master_status_init() enables the processing of child status updates
+/*	for the specified service. Child process status updates (process
+/*	available, process taken) are passed on to the master_avail_XXX()
+/*	routines.
+/*
+/*	master_status_cleanup() disables child status update processing
+/*	for the specified service.
+/* DIAGNOSTICS
+/*	Panic: internal inconsistency. Warnings: a child process sends
+/*	incomplete or incorrect information.
+/* BUGS
+/* SEE ALSO
+/*	master_avail(3)
+/* 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
+/*--*/
+
+/* System libraries. */
+
+#include <sys_defs.h>
+#include <unistd.h>
+
+/* Utility library. */
+
+#include <msg.h>
+#include <events.h>
+#include <binhash.h>
+#include <iostuff.h>
+
+/* Application-specific. */
+
+#include "master_proto.h"
+#include "master.h"
+
+/* master_status_event - status read event handler */
+
+static void master_status_event(int event, void *context)
+{
+    const char *myname = "master_status_event";
+    MASTER_SERV *serv = (MASTER_SERV *) context;
+    MASTER_STATUS stat;
+    MASTER_PROC *proc;
+    MASTER_PID pid;
+    int     n;
+
+    if (event == 0)				/* XXX Can this happen?  */
+	return;
+
+    /*
+     * We always keep the child end of the status pipe open, so an EOF read
+     * condition means that we're seriously confused. We use non-blocking
+     * reads so that we don't get stuck when someone sends a partial message.
+     * Messages are short, so a partial read means someone wrote less than a
+     * whole status message. Hopefully the next read will be in sync again...
+     * We use a global child process status table because when a child dies
+     * only its pid is known - we do not know what service it came from.
+     */
+    switch (n = read(serv->status_fd[0], (void *) &stat, sizeof(stat))) {
+
+    case -1:
+	msg_warn("%s: read: %m", myname);
+	return;
+
+    case 0:
+	msg_panic("%s: read EOF status", myname);
+	/* NOTREACHED */
+
+    default:
+	msg_warn("service %s(%s): child (pid %d) sent partial status update (%d bytes)",
+		 serv->ext_name, serv->name, stat.pid, n);
+	return;
+
+    case sizeof(stat):
+	pid = stat.pid;
+	if (msg_verbose)
+	    msg_info("%s: pid %d gen %u avail %d",
+		     myname, stat.pid, stat.gen, stat.avail);
+    }
+
+    /*
+     * Sanity checks. Do not freak out when the child sends garbage because
+     * it is confused or for other reasons. However, be sure to freak out
+     * when our own data structures are inconsistent. A process not found
+     * condition can happen when we reap a process before receiving its
+     * status update, so this is not an error.
+     */
+    if ((proc = (MASTER_PROC *) binhash_find(master_child_table,
+					(void *) &pid, sizeof(pid))) == 0) {
+	if (msg_verbose)
+	    msg_info("%s: process id not found: %d", myname, stat.pid);
+	return;
+    }
+    if (proc->gen != stat.gen) {
+	msg_info("ignoring status update from child pid %d generation %u",
+		 pid, stat.gen);
+	return;
+    }
+    if (proc->serv != serv)
+	msg_panic("%s: pointer corruption: %p != %p",
+		  myname, (void *) proc->serv, (void *) serv);
+
+    /*
+     * Update our idea of the child process status. Allow redundant status
+     * updates, because different types of events may be processed out of
+     * order. Otherwise, warn about weird status updates but do not take
+     * action. It's all gossip after all.
+     */
+    if (proc->avail == stat.avail)
+	return;
+    switch (stat.avail) {
+    case MASTER_STAT_AVAIL:
+	proc->use_count++;
+	master_avail_more(serv, proc);
+	break;
+    case MASTER_STAT_TAKEN:
+	master_avail_less(serv, proc);
+	break;
+    default:
+	msg_warn("%s: ignoring unknown status: %d allegedly from pid: %d",
+		 myname, stat.pid, stat.avail);
+	break;
+    }
+}
+
+/* master_status_init - start status event processing for this service */
+
+void    master_status_init(MASTER_SERV *serv)
+{
+    const char *myname = "master_status_init";
+
+    /*
+     * Sanity checks.
+     */
+    if (serv->status_fd[0] >= 0 || serv->status_fd[1] >= 0)
+	msg_panic("%s: status events already enabled", myname);
+    if (msg_verbose)
+	msg_info("%s: %s", myname, serv->name);
+
+    /*
+     * Make the read end of this service's status pipe non-blocking so that
+     * we can detect partial writes on the child side. We use a duplex pipe
+     * so that the child side becomes readable when the master goes away.
+     */
+    if (duplex_pipe(serv->status_fd) < 0)
+	msg_fatal("pipe: %m");
+    non_blocking(serv->status_fd[0], BLOCKING);
+    close_on_exec(serv->status_fd[0], CLOSE_ON_EXEC);
+    close_on_exec(serv->status_fd[1], CLOSE_ON_EXEC);
+    event_enable_read(serv->status_fd[0], master_status_event, (void *) serv);
+}
+
+/* master_status_cleanup - stop status event processing for this service */
+
+void    master_status_cleanup(MASTER_SERV *serv)
+{
+    const char *myname = "master_status_cleanup";
+
+    /*
+     * Sanity checks.
+     */
+    if (serv->status_fd[0] < 0 || serv->status_fd[1] < 0)
+	msg_panic("%s: status events not enabled", myname);
+    if (msg_verbose)
+	msg_info("%s: %s", myname, serv->name);
+
+    /*
+     * Dispose of this service's status pipe after disabling read events.
+     */
+    event_disable_readwrite(serv->status_fd[0]);
+    if (close(serv->status_fd[0]) != 0)
+	msg_warn("%s: close status descriptor (read side): %m", myname);
+    if (close(serv->status_fd[1]) != 0)
+	msg_warn("%s: close status descriptor (write side): %m", myname);
+    serv->status_fd[0] = serv->status_fd[1] = -1;
+}