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+/*++
+/* NAME
+/* postlogd 8
+/* SUMMARY
+/* Postfix internal log server
+/* SYNOPSIS
+/* \fBpostlogd\fR [generic Postfix daemon options]
+/* DESCRIPTION
+/* This program logs events on behalf of Postfix programs
+/* when the maillog configuration parameter specifies a non-empty
+/* value.
+/* BUGS
+/* Non-daemon Postfix programs don't know that they should log
+/* to the internal logging service before they have processed
+/* command-line options and main.cf parameters. These programs
+/* still log earlier events to the syslog service.
+/*
+/* If Postfix is down, the non-daemon programs \fBpostfix\fR(1),
+/* \fBpostsuper\fR(1), \fBpostmulti\fR(1), and \fBpostlog\fR(1),
+/* will log directly to \fB$maillog_file\fR. These programs
+/* expect to run with root privileges, for example during
+/* Postfix start-up, reload, or shutdown.
+/*
+/* Other non-daemon Postfix programs will never write directly to
+/* \fB$maillog_file\fR (also, logging to stdout would interfere
+/* with the operation of some of these programs). These programs
+/* can log to \fBpostlogd\fR(8) if they are run by the super-user,
+/* or if their executable file has set-gid permission. Do not
+/* set this permission on programs other than \fBpostdrop\fR(1)
+/* and \fBpostqueue\fR(1).
+/* CONFIGURATION PARAMETERS
+/* .ad
+/* .fi
+/* Changes to \fBmain.cf\fR are picked up automatically, as
+/* \fBpostlogd\fR(8) processes run for only a limited amount
+/* of time. Use the command "\fBpostfix reload\fR" to speed
+/* up a change.
+/*
+/* The text below provides only a parameter summary. See
+/* \fBpostconf\fR(5) for more details including examples.
+/* .IP "\fBconfig_directory (see 'postconf -d' output)\fR"
+/* The default location of the Postfix main.cf and master.cf
+/* configuration files.
+/* .IP "\fBmaillog_file (empty)\fR"
+/* The name of an optional logfile that is written by the Postfix
+/* \fBpostlogd\fR(8) service.
+/* .IP "\fBprocess_id (read-only)\fR"
+/* The process ID of a Postfix command or daemon process.
+/* .IP "\fBprocess_name (read-only)\fR"
+/* The process name of a Postfix command or daemon process.
+/* .IP "\fBsyslog_name (see 'postconf -d' output)\fR"
+/* A prefix that is prepended to the process name in syslog
+/* records, so that, for example, "smtpd" becomes "prefix/smtpd".
+/* .IP "\fBservice_name (read-only)\fR"
+/* The master.cf service name of a Postfix daemon process.
+/* .IP "\fBpostlogd_watchdog_timeout (10s)\fR"
+/* How much time a \fBpostlogd\fR(8) process may take to process a request
+/* before it is terminated by a built-in watchdog timer.
+/* SEE ALSO
+/* postconf(5), configuration parameters
+/* syslogd(8), system logging
+/* README_FILES
+/* .ad
+/* .fi
+/* Use "\fBpostconf readme_directory\fR" or
+/* "\fBpostconf html_directory\fR" to locate this information.
+/* .na
+/* .nf
+/* MAILLOG_README, Postfix logging to file or stdout
+/* LICENSE
+/* .ad
+/* .fi
+/* The Secure Mailer license must be distributed with this software.
+/* HISTORY
+/* .ad
+/* .fi
+/* This service was introduced with Postfix version 3.4.
+/* AUTHOR(S)
+/* Wietse Venema
+/* Google, Inc.
+/* 111 8th Avenue
+/* New York, NY 10011, USA
+/*--*/
+
+ /*
+ * System library.
+ */
+#include <sys_defs.h>
+
+ /*
+ * Utility library.
+ */
+#include <logwriter.h>
+#include <msg.h>
+#include <msg_logger.h>
+#include <stringops.h>
+#include <vstream.h>
+
+ /*
+ * Global library.
+ */
+#include <mail_params.h>
+#include <mail_task.h>
+#include <mail_version.h>
+#include <maillog_client.h>
+
+ /*
+ * Server skeleton.
+ */
+#include <mail_server.h>
+
+ /*
+ * Tunable parameters.
+ */
+int var_postlogd_watchdog;
+
+ /*
+ * Silly little macros.
+ */
+#define STR(x) vstring_str(x)
+#define LEN(x) VSTRING_LEN(x)
+
+ /*
+ * Logfile stream.
+ */
+static VSTREAM *postlogd_stream = 0;
+
+/* postlogd_fallback - log messages from postlogd(8) itself */
+
+static void postlogd_fallback(const char *buf)
+{
+ (void) logwriter_write(postlogd_stream, buf, strlen(buf));
+}
+
+/* postlogd_service - perform service for client */
+
+static void postlogd_service(char *buf, ssize_t len, char *unused_service,
+ char **unused_argv)
+{
+
+ if (postlogd_stream) {
+ (void) logwriter_write(postlogd_stream, buf, len);
+ }
+
+ /*
+ * After a configuration change that removes the maillog_file pathname,
+ * this service may still receive messages (after "postfix reload" or
+ * after process refresh) from programs that use the old maillog_file
+ * setting. Redirect those messages to the current logging mechanism.
+ */
+ else {
+ char *bp = buf;
+ char *progname_pid;
+
+ /*
+ * Avoid surprises: strip off the date, time, host, and program[pid]:
+ * prefix that were prepended by msg_logger(3). Then, hope that the
+ * current logging driver suppresses its own PID, when it sees that
+ * there is a PID embedded in the 'program name'.
+ */
+ (void) mystrtok(&bp, CHARS_SPACE); /* month */
+ (void) mystrtok(&bp, CHARS_SPACE); /* day */
+ (void) mystrtok(&bp, CHARS_SPACE); /* time */
+ (void) mystrtok(&bp, CHARS_SPACE); /* host */
+ progname_pid = mystrtok(&bp, ":" CHARS_SPACE); /* name[pid] sans ':' */
+ bp += strspn(bp, CHARS_SPACE);
+ if (progname_pid)
+ maillog_client_init(progname_pid, MAILLOG_CLIENT_FLAG_NONE);
+ msg_info("%.*s", (int) (len - (bp - buf)), bp);
+
+ /*
+ * Restore the program name, in case postlogd(8) needs to log
+ * something about itself. We have to call maillog_client_init() in
+ * any case, because neither msg_syslog_init() nor openlog() make a
+ * copy of the name argument. We can't leave that pointing into the
+ * middle of the above message buffer.
+ */
+ maillog_client_init(mail_task((char *) 0), MAILLOG_CLIENT_FLAG_NONE);
+ }
+}
+
+/* pre_jail_init - pre-jail handling */
+
+static void pre_jail_init(char *unused_service_name, char **argv)
+{
+
+ /*
+ * During process initialization, the postlogd daemon will log events to
+ * the postlog socket, so that they can be logged to file later. Once the
+ * postlogd daemon is handling requests, it will stop logging to the
+ * postlog socket and will instead write to the logfile, to avoid
+ * infinite recursion.
+ */
+
+ /*
+ * Sanity check. This service takes no command-line arguments.
+ */
+ if (argv[0])
+ msg_fatal("unexpected command-line argument: %s", argv[0]);
+
+ /*
+ * After a configuration change that removes the maillog_file pathname,
+ * this service may still receive messages from processes that still use
+ * the old configuration. Those messages will have to be redirected to
+ * the current logging subsystem.
+ */
+ if (*var_maillog_file != 0) {
+
+ /*
+ * Instantiate the logwriter or bust.
+ */
+ postlogd_stream = logwriter_open_or_die(var_maillog_file);
+
+ /*
+ * Inform the msg_logger client to stop using the postlog socket, and
+ * to call our logwriter.
+ */
+ msg_logger_control(CA_MSG_LOGGER_CTL_FALLBACK_ONLY,
+ CA_MSG_LOGGER_CTL_FALLBACK_FN(postlogd_fallback),
+ CA_MSG_LOGGER_CTL_END);
+ }
+}
+
+/* post_jail_init - post-jail initialization */
+
+static void post_jail_init(char *unused_name, char **unused_argv)
+{
+
+ /*
+ * Prevent automatic process suicide after a limited number of client
+ * requests. It is OK to terminate after a limited amount of idle time.
+ */
+ var_use_limit = 0;
+}
+
+MAIL_VERSION_STAMP_DECLARE;
+
+/* main - pass control to the multi-threaded skeleton */
+
+int main(int argc, char **argv)
+{
+ static const CONFIG_TIME_TABLE time_table[] = {
+ VAR_POSTLOGD_WATCHDOG, DEF_POSTLOGD_WATCHDOG, &var_postlogd_watchdog, 10, 0,
+ 0,
+ };
+
+ /*
+ * Fingerprint executables and core dumps.
+ */
+ MAIL_VERSION_STAMP_ALLOCATE;
+
+ /*
+ * This is a datagram service, not a stream service, so that postlogd can
+ * restart immediately after "postfix reload" without requiring clients
+ * to resend messages. Those messages remain queued in the kernel until a
+ * new postlogd process retrieves them. It would be unreasonable to
+ * require that clients retransmit logs, especially in the case of a
+ * fatal or panic error.
+ */
+ dgram_server_main(argc, argv, postlogd_service,
+ CA_MAIL_SERVER_TIME_TABLE(time_table),
+ CA_MAIL_SERVER_PRE_INIT(pre_jail_init),
+ CA_MAIL_SERVER_POST_INIT(post_jail_init),
+ CA_MAIL_SERVER_SOLITARY,
+ CA_MAIL_SERVER_WATCHDOG(&var_postlogd_watchdog),
+ 0);
+}