showq.c

[詳解]

/*++
/* NAME
/*  showq 8
/* SUMMARY
/*  list the Postfix mail queue
/* SYNOPSIS
/*  \fBshowq\fR [generic Postfix daemon options]
/* DESCRIPTION
/*  The \fBshowq\fR(8) daemon reports the Postfix mail queue status.
/*  The output is meant to be formatted by the postqueue(1) command,
/*  as it emulates the Sendmail `mailq' command.
/*
/*  The \fBshowq\fR(8) daemon can also be run in stand-alone mode
/*  by the superuser. This mode of operation is used to emulate
/*  the `mailq' command while the Postfix mail system is down.
/* SECURITY
/* .ad
/* .fi
/*  The \fBshowq\fR(8) daemon can run in a chroot jail at fixed low
/*  privilege, and takes no input from the client. Its service port
/*  is accessible to local untrusted users, so the service can be
/*  susceptible to denial of service attacks.
/* STANDARDS
/* .ad
/* .fi
/*  None. The \fBshowq\fR(8) daemon does not interact with the
/*  outside world.
/* DIAGNOSTICS
/*  Problems and transactions are logged to \fBsyslogd\fR(8).
/* CONFIGURATION PARAMETERS
/* .ad
/* .fi
/*  Changes to \fBmain.cf\fR are picked up automatically as \fBshowq\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 "\fBdaemon_timeout (18000s)\fR"
/*  How much time a Postfix daemon process may take to handle a
/*  request before it is terminated by a built-in watchdog timer.
/* .IP "\fBduplicate_filter_limit (1000)\fR"
/*  The maximal number of addresses remembered by the address
/*  duplicate filter for \fBaliases\fR(5) or \fBvirtual\fR(5) alias expansion, or
/*  for \fBshowq\fR(8) queue displays.
/* .IP "\fBempty_address_recipient (MAILER-DAEMON)\fR"
/*  The recipient of mail addressed to the null address.
/* .IP "\fBipc_timeout (3600s)\fR"
/*  The time limit for sending or receiving information over an internal
/*  communication channel.
/* .IP "\fBmax_idle (100s)\fR"
/*  The maximum amount of time that an idle Postfix daemon process waits
/*  for an incoming connection before terminating voluntarily.
/* .IP "\fBmax_use (100)\fR"
/*  The maximal number of incoming connections that a Postfix daemon
/*  process will service before terminating voluntarily.
/* .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 "\fBqueue_directory (see 'postconf -d' output)\fR"
/*  The location of the Postfix top-level queue directory.
/* .IP "\fBsyslog_facility (mail)\fR"
/*  The syslog facility of Postfix logging.
/* .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".
/* .PP
/*  Available in Postfix version 2.9 and later:
/* .IP "\fBenable_long_queue_ids (no)\fR"
/*  Enable long, non-repeating, queue IDs (queue file names).
/* .PP
/*  Available in Postfix 3.3 and later:
/* .IP "\fBservice_name (read-only)\fR"
/*  The master.cf service name of a Postfix daemon process.
/* FILES
/*  /var/spool/postfix, queue directories
/* SEE ALSO
/*  pickup(8), local mail pickup service
/*  cleanup(8), canonicalize and enqueue mail
/*  qmgr(8), queue manager
/*  postconf(5), configuration parameters
/*  master(8), process manager
/*  syslogd(8), system logging
/* 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 library. */

#include <sys_defs.h>
#include <sys/stat.h>
#include <dirent.h>
#include <stdlib.h>
#include <unistd.h>
#include <errno.h>
#include <fcntl.h>
#include <time.h>
#include <string.h>
#include <ctype.h>

/* Utility library. */

#include <msg.h>
#include <scan_dir.h>
#include <vstring.h>
#include <vstream.h>
#include <vstring_vstream.h>
#include <stringops.h>
#include <mymalloc.h>
#include <htable.h>

/* Global library. */

#include <mail_queue.h>
#include <mail_open_ok.h>
#include <mail_proto.h>
#include <mail_date.h>
#include <mail_params.h>
#include <mail_version.h>
#include <mail_scan_dir.h>
#include <mail_conf.h>
#include <record.h>
#include <rec_type.h>
#include <quote_822_local.h>
#include <mail_addr.h>
#include <bounce_log.h>

/* Single-threaded server skeleton. */

#include <mail_server.h>

/* Application-specific. */

int     var_dup_filter_limit;
char   *var_empty_addr;

static void showq_reasons(VSTREAM *, BOUNCE_LOG *, RCPT_BUF *, DSN_BUF *,
                      HTABLE *);

#define STR(x)  vstring_str(x)

/* showq_report - report status of sender and recipients */

static void showq_report(VSTREAM *client, char *queue, char *id,
                     VSTREAM *qfile, long size, time_t mtime)
{
    VSTRING *buf = vstring_alloc(100);
    VSTRING *printable_quoted_addr = vstring_alloc(100);
    int     rec_type;
    time_t  arrival_time = 0;
    char   *start;
    long    msg_size = size;
    BOUNCE_LOG *logfile;
    HTABLE *dup_filter = 0;
    RCPT_BUF *rcpt_buf = 0;
    DSN_BUF *dsn_buf = 0;
    int     sender_seen = 0;
    int     msg_size_ok = 0;

    /*
     * Let the optimizer worry about eliminating duplicate code.
     */
#define SHOWQ_CLEANUP_AND_RETURN { \
    if (sender_seen > 0) \
        attr_print(client, ATTR_FLAG_NONE, ATTR_TYPE_END); \
    vstring_free(buf); \
    vstring_free(printable_quoted_addr); \
    if (rcpt_buf) \
        rcpb_free(rcpt_buf); \
    if (dsn_buf) \
        dsb_free(dsn_buf); \
    if (dup_filter) \
        htable_free(dup_filter, (void (*) (void *)) 0); \
    }

    /*
     * XXX addresses in defer logfiles are in printable quoted form, while
     * addresses in message envelope records are in raw unquoted form. This
     * may change once we replace the present ad-hoc bounce/defer logfile
     * format by one that is transparent for control etc. characters. See
     * also: bounce/bounce_append_service.c.
     * 
     * XXX With Postfix <= 2.0, "postsuper -r" results in obsolete size records
     * from previous cleanup runs. Skip the obsolete size records.
     */
    while (!vstream_ferror(client) && (rec_type = rec_get(qfile, buf, 0)) > 0) {
    start = vstring_str(buf);
    if (msg_verbose)
        msg_info("record %c %s", rec_type, printable(start, '?'));
    switch (rec_type) {
    case REC_TYPE_TIME:
        /* TODO: parse seconds and microseconds. */
        if (arrival_time == 0)
        arrival_time = atol(start);
        break;
    case REC_TYPE_SIZE:
        if (msg_size_ok == 0) {
        msg_size_ok = (start[strspn(start, "0123456789 ")] == 0
                   && (msg_size = atol(start)) >= 0);
        if (msg_size_ok == 0) {
            msg_warn("%s: malformed size record: %.100s "
                 "-- using file size instead",
                 id, printable(start, '?'));
            msg_size = size;
        }
        }
        break;
    case REC_TYPE_FROM:
        if (*start == 0)
        start = var_empty_addr;
        quote_822_local(printable_quoted_addr, start);
        printable(STR(printable_quoted_addr), '?');
        if (sender_seen++ > 0) {
        msg_warn("%s: duplicate sender address: %s "
             "-- skipping remainder of this file",
             id, STR(printable_quoted_addr));
        SHOWQ_CLEANUP_AND_RETURN;
        }
        attr_print(client, ATTR_FLAG_MORE,
               SEND_ATTR_STR(MAIL_ATTR_QUEUE, queue),
               SEND_ATTR_STR(MAIL_ATTR_QUEUEID, id),
               SEND_ATTR_LONG(MAIL_ATTR_TIME, arrival_time > 0 ?
                      arrival_time : mtime),
               SEND_ATTR_LONG(MAIL_ATTR_SIZE, msg_size),
               SEND_ATTR_STR(MAIL_ATTR_SENDER,
                     STR(printable_quoted_addr)),
               ATTR_TYPE_END);
        break;
    case REC_TYPE_RCPT:
        if (sender_seen == 0) {
        msg_warn("%s: missing sender address: %s "
             "-- skipping remainder of this file",
             id, STR(printable_quoted_addr));
        SHOWQ_CLEANUP_AND_RETURN;
        }
        if (*start == 0)            /* can't happen? */
        start = var_empty_addr;
        quote_822_local(printable_quoted_addr, start);
        printable(STR(printable_quoted_addr), '?');
        if (dup_filter == 0
          || htable_locate(dup_filter, STR(printable_quoted_addr)) == 0)
        attr_print(client, ATTR_FLAG_MORE,
               SEND_ATTR_STR(MAIL_ATTR_RECIP,
                     STR(printable_quoted_addr)),
               SEND_ATTR_STR(MAIL_ATTR_WHY, ""),
               ATTR_TYPE_END);
        break;
    case REC_TYPE_MESG:
        if (msg_size_ok && vstream_fseek(qfile, msg_size, SEEK_CUR) < 0)
        msg_fatal("seek file %s: %m", VSTREAM_PATH(qfile));
        break;
    case REC_TYPE_END:
        break;
    }

    /*
     * Before listing any recipients from the queue file, try to list
     * recipients from the corresponding defer logfile with per-recipient
     * descriptions why delivery was deferred.
     * 
     * The defer logfile is not necessarily complete: delivery may be
     * interrupted (postfix stop or reload) before all recipients have
     * been tried.
     * 
     * Therefore we keep a record of recipients found in the defer logfile,
     * and try to avoid listing those recipients again when processing
     * recipients from the queue file.
     */
    if (rec_type == REC_TYPE_FROM
        && (logfile = bounce_log_open(MAIL_QUEUE_DEFER, id, O_RDONLY, 0)) != 0) {
        if (dup_filter != 0)
        msg_panic("showq_report: attempt to reuse duplicate filter");
        dup_filter = htable_create(var_dup_filter_limit);
        if (rcpt_buf == 0)
        rcpt_buf = rcpb_create();
        if (dsn_buf == 0)
        dsn_buf = dsb_create();
        showq_reasons(client, logfile, rcpt_buf, dsn_buf, dup_filter);
        if (bounce_log_close(logfile))
        msg_warn("close %s %s: %m", MAIL_QUEUE_DEFER, id);
    }
    }
    SHOWQ_CLEANUP_AND_RETURN;
}

/* showq_reasons - show deferral reasons */

static void showq_reasons(VSTREAM *client, BOUNCE_LOG *bp, RCPT_BUF *rcpt_buf,
                      DSN_BUF *dsn_buf, HTABLE *dup_filter)
{
    RECIPIENT *rcpt = &rcpt_buf->rcpt;
    DSN    *dsn = &dsn_buf->dsn;

    while (bounce_log_read(bp, rcpt_buf, dsn_buf) != 0) {

    /*
     * Update the duplicate filter.
     */
    if (var_dup_filter_limit == 0
        || dup_filter->used < var_dup_filter_limit)
        if (htable_locate(dup_filter, rcpt->address) == 0)
        htable_enter(dup_filter, rcpt->address, (void *) 0);

    attr_print(client, ATTR_FLAG_MORE,
           SEND_ATTR_STR(MAIL_ATTR_RECIP, rcpt->address),
           SEND_ATTR_STR(MAIL_ATTR_WHY, dsn->reason),
           ATTR_TYPE_END);
    }
}


/* showq_service - service client */

static void showq_service(VSTREAM *client, char *unused_service, char **argv)
{
    VSTREAM *qfile;
    const char *path;
    int     status;
    char   *id;
    struct stat st;
    struct queue_info {
    char   *name;           /* queue name */
    char   *(*scan_next) (SCAN_DIR *);  /* flat or recursive */
    };
    struct queue_info *qp;

    static struct queue_info queue_info[] = {
    MAIL_QUEUE_MAILDROP, scan_dir_next,
    MAIL_QUEUE_ACTIVE, mail_scan_dir_next,
    MAIL_QUEUE_INCOMING, mail_scan_dir_next,
    MAIL_QUEUE_DEFERRED, mail_scan_dir_next,
    MAIL_QUEUE_HOLD, mail_scan_dir_next,
    0,
    };

    /*
     * Sanity check. This service takes no command-line arguments.
     */
    if (argv[0])
    msg_fatal("unexpected command-line argument: %s", argv[0]);

    /*
     * Skip any files that have the wrong permissions. If we can't open an
     * existing file, assume the system is out of resources or that it is
     * mis-configured, and force backoff by raising a fatal error.
     */
    for (qp = queue_info; qp->name != 0; qp++) {
    SCAN_DIR *scan = scan_dir_open(qp->name);
    char   *saved_id = 0;

    while ((id = qp->scan_next(scan)) != 0) {

        /*
         * XXX I have seen showq loop on the same queue id. That would be
         * an operating system bug, but who cares whose fault it is. Make
         * sure this will never happen again.
         */
        if (saved_id) {
        if (strcmp(saved_id, id) == 0) {
            msg_warn("readdir loop on queue %s id %s", qp->name, id);
            break;
        }
        myfree(saved_id);
        }
        saved_id = mystrdup(id);
        status = mail_open_ok(qp->name, id, &st, &path);
        if (status == MAIL_OPEN_YES) {
        if ((qfile = mail_queue_open(qp->name, id, O_RDONLY, 0)) != 0) {
            showq_report(client, qp->name, id, qfile, (long) st.st_size,
                 st.st_mtime);
            if (vstream_fclose(qfile))
            msg_warn("close file %s %s: %m", qp->name, id);
        } else if (errno != ENOENT) {
            msg_warn("open %s %s: %m", qp->name, id);
        }
        }
        vstream_fflush(client);
    }
    if (saved_id)
        myfree(saved_id);
    scan_dir_close(scan);
    }
    attr_print(client, ATTR_FLAG_NONE, ATTR_TYPE_END);
}

MAIL_VERSION_STAMP_DECLARE;

/* main - pass control to the single-threaded server skeleton */

int     main(int argc, char **argv)
{
    static const CONFIG_INT_TABLE int_table[] = {
    VAR_DUP_FILTER_LIMIT, DEF_DUP_FILTER_LIMIT, &var_dup_filter_limit, 0, 0,
    0,
    };
    CONFIG_STR_TABLE str_table[] = {
    VAR_EMPTY_ADDR, DEF_EMPTY_ADDR, &var_empty_addr, 1, 0,
    0,
    };

    /*
     * Fingerprint executables and core dumps.
     */
    MAIL_VERSION_STAMP_ALLOCATE;

    single_server_main(argc, argv, showq_service,
               CA_MAIL_SERVER_INT_TABLE(int_table),
               CA_MAIL_SERVER_STR_TABLE(str_table),
               0);
}