post_mail.c

[詳解]

/*++
/* NAME
/*  post_mail 3
/* SUMMARY
/*  convenient mail posting interface
/* SYNOPSIS
/*  #include <post_mail.h>
/*
/*  VSTREAM *post_mail_fopen(sender, recipient, source_class, trace_flags,
/*      utf8_flags, queue_id)
/*  const char *sender;
/*  const char *recipient;
/*  int source_class;
/*  int trace_flags;
/*  int utf8_flags;
/*  VSTRING *queue_id;
/*
/*  VSTREAM *post_mail_fopen_nowait(sender, recipient, source_class,
/*                  trace_flags, utf8_flags, queue_id)
/*  const char *sender;
/*  const char *recipient;
/*  int source_class;
/*  int trace_flags;
/*  int utf8_flags;
/*  VSTRING *queue_id;
/*
/*  void    post_mail_fopen_async(sender, recipient, source_class,
/*                  trace_flags, utf8_flags,
/*                  queue_id, notify, context)
/*  const char *sender;
/*  const char *recipient;
/*  int source_class;
/*  int trace_flags;
/*  int utf8_flags;
/*  VSTRING *queue_id;
/*  void    (*notify)(VSTREAM *stream, void *context);
/*  void    *context;
/*
/*  int post_mail_fprintf(stream, format, ...)
/*  VSTREAM *stream;
/*  const char *format;
/*
/*  int post_mail_fputs(stream, str)
/*  VSTREAM *stream;
/*  const char *str;
/*
/*  int post_mail_buffer(stream, buf, len)
/*  VSTREAM *stream;
/*  const char *buffer;
/*
/*  int POST_MAIL_BUFFER(stream, buf)
/*  VSTREAM *stream;
/*  VSTRING *buffer;
/*
/*  int post_mail_fclose(stream)
/*  VSTREAM *STREAM;
/*
/*  void    post_mail_fclose_async(stream, notify, context)
/*  VSTREAM *stream;
/*  void    (*notify)(int status, void *context);
/*  void    *context;
/* DESCRIPTION
/*  This module provides a convenient interface for the most
/*  common case of sending one message to one recipient. It
/*  allows the application to concentrate on message content,
/*  without having to worry about queue file structure details.
/*
/*  post_mail_fopen() opens a connection to the cleanup service
/*  and waits until the service is available, does some option
/*  negotiation, generates message envelope records, and generates
/*  Received: and Date: message headers.  The result is a stream
/*  handle that can be used for sending message records.
/*
/*  post_mail_fopen_nowait() tries to contact the cleanup service
/*  only once, and does not wait until the cleanup service is
/*  available.  Otherwise it is identical to post_mail_fopen().
/*
/*  post_mail_fopen_async() contacts the cleanup service and
/*  invokes the caller-specified notify routine, with the
/*  open stream and the caller-specified context when the
/*  service responds, or with a null stream and the caller-specified
/*  context when the request could not be completed. It is the
/*  responsibility of the application to close an open stream.
/*
/*  post_mail_fprintf() formats message content (header or body)
/*  and sends it to the cleanup service.
/*
/*  post_mail_fputs() sends pre-formatted content (header or body)
/*  to the cleanup service.
/*
/*  post_mail_buffer() sends a pre-formatted buffer to the
/*  cleanup service.
/*
/*  POST_MAIL_BUFFER() is a wrapper for post_mail_buffer() that
/*  evaluates its buffer argument more than once.
/*
/*  post_mail_fclose() completes the posting of a message.
/*
/*  post_mail_fclose_async() completes the posting of a message
/*  and upon completion invokes the caller-specified notify
/*  routine, with the cleanup status and caller-specified context
/*  as arguments.
/*
/*  Arguments:
/* .IP sender
/*  The sender envelope address. It is up to the application
/*  to produce From: headers.
/* .IP recipient
/*  The recipient envelope address. It is up to the application
/*  to produce To: headers.
/* .IP source_class
/*  The message source class, as defined in \fB<mail_proto.h>\fR.
/*  Depending on the setting of the internal_mail_source_classes
/*  and smtputf8_autodetect_classes parameters, the message
/*  will or won't be subject to content inspection or SMTPUTF8
/*  autodetection.
/* .IP trace_flags
/*  Message tracing flags as specified in \fB<deliver_request.h>\fR.
/* .IP utf8_flags
/*  Flags defined in <smtputf8.h>. Flags other than
/*  SMTPUTF8_FLAG_REQUESTED are ignored.
/* .IP queue_id
/*  Null pointer, or pointer to buffer that receives the queue
/*  ID of the new message.
/* .IP stream
/*  A stream opened by mail_post_fopen().
/* .IP notify
/*  Application call-back routine.
/* .IP context
/*  Application call-back context.
/* DIAGNOSTICS
/*  post_mail_fopen_nowait() returns a null pointer when the
/*  cleanup service is not available immediately.
/*
/*  post_mail_fopen_async() returns a null pointer when the
/*  attempt to contact the cleanup service fails immediately.
/*
/*  post_mail_fprintf(), post_mail_fputs() post_mail_fclose(),
/*  and post_mail_buffer() return the binary OR of the error
/*  status codes defined in \fI<cleanup_user.h>\fR.
/*
/*  Fatal errors: cleanup initial handshake errors. This means
/*  the client and server speak incompatible protocols.
/* SEE ALSO
/*  cleanup_user(3h) cleanup options and results
/*  cleanup_strerror(3) translate results to text
/*  cleanup(8) cleanup service
/* 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/time.h>
#include <stdlib.h>         /* 44BSD stdarg.h uses abort() */
#include <stdarg.h>
#include <string.h>

/* Utility library. */

#include <msg.h>
#include <vstream.h>
#include <vstring.h>
#include <mymalloc.h>
#include <events.h>

/* Global library. */

#include <mail_params.h>
#include <record.h>
#include <rec_type.h>
#include <mail_proto.h>
#include <cleanup_user.h>
#include <post_mail.h>
#include <mail_date.h>

 /*
  * Call-back state for asynchronous connection requests.
  */
typedef struct {
    char   *sender;
    char   *recipient;
    int     source_class;
    int     trace_flags;
    int     utf8_flags;
    POST_MAIL_NOTIFY notify;
    void   *context;
    VSTREAM *stream;
    VSTRING *queue_id;
} POST_MAIL_STATE;

 /*
  * Call-back state for asynchronous close requests.
  */
typedef struct {
    int     status;
    VSTREAM *stream;
    POST_MAIL_FCLOSE_NOTIFY notify;
    void   *context;
} POST_MAIL_FCLOSE_STATE;

/* post_mail_init - initial negotiations */

static void post_mail_init(VSTREAM *stream, const char *sender,
                       const char *recipient,
                       int source_class, int trace_flags,
                       int utf8_flags, VSTRING *queue_id)
{
    VSTRING *id = queue_id ? queue_id : vstring_alloc(100);
    struct timeval now;
    const char *date;
    int     cleanup_flags =
    int_filt_flags(source_class) | CLEANUP_FLAG_MASK_INTERNAL
    | smtputf8_autodetect(source_class)
    | ((utf8_flags & SMTPUTF8_FLAG_REQUESTED) ? CLEANUP_FLAG_SMTPUTF8 : 0);

    GETTIMEOFDAY(&now);
    date = mail_date(now.tv_sec);

    /*
     * XXX Don't flush buffers while sending the initial message records.
     * That would cause deadlock between verify(8) and cleanup(8) servers.
     */
    vstream_control(stream, VSTREAM_CTL_BUFSIZE, 2 * VSTREAM_BUFSIZE,
            VSTREAM_CTL_END);

    /*
     * Negotiate with the cleanup service. Give up if we can't agree.
     */
    if (attr_scan(stream, ATTR_FLAG_STRICT,
          RECV_ATTR_STR(MAIL_ATTR_QUEUEID, id),
          ATTR_TYPE_END) != 1
    || attr_print(stream, ATTR_FLAG_NONE,
              SEND_ATTR_INT(MAIL_ATTR_FLAGS, cleanup_flags),
              ATTR_TYPE_END) != 0)
    msg_fatal("unable to contact the %s service", var_cleanup_service);

    /*
     * Generate a minimal envelope section. The cleanup service will add a
     * size record.
     */
    rec_fprintf(stream, REC_TYPE_TIME, REC_TYPE_TIME_FORMAT,
        REC_TYPE_TIME_ARG(now));
    rec_fprintf(stream, REC_TYPE_ATTR, "%s=%s",
        MAIL_ATTR_LOG_ORIGIN, MAIL_ATTR_ORG_LOCAL);
    rec_fprintf(stream, REC_TYPE_ATTR, "%s=%d",
        MAIL_ATTR_TRACE_FLAGS, trace_flags);
    rec_fputs(stream, REC_TYPE_FROM, sender);
    rec_fputs(stream, REC_TYPE_RCPT, recipient);
    rec_fputs(stream, REC_TYPE_MESG, "");

    /*
     * Do the Received: and Date: header lines. This allows us to shave a few
     * cycles by using the expensive date conversion result for both.
     */
    post_mail_fprintf(stream, "Received: by %s (%s)",
              var_myhostname, var_mail_name);
    post_mail_fprintf(stream, "\tid %s; %s", vstring_str(id), date);
    post_mail_fprintf(stream, "Date: %s", date);
    if (queue_id == 0)
    vstring_free(id);
}

/* post_mail_fopen - prepare for posting a message */

VSTREAM *post_mail_fopen(const char *sender, const char *recipient,
                     int source_class, int trace_flags,
                     int utf8_flags, VSTRING *queue_id)
{
    VSTREAM *stream;

    stream = mail_connect_wait(MAIL_CLASS_PUBLIC, var_cleanup_service);
    post_mail_init(stream, sender, recipient, source_class, trace_flags,
           utf8_flags, queue_id);
    return (stream);
}

/* post_mail_fopen_nowait - prepare for posting a message */

VSTREAM *post_mail_fopen_nowait(const char *sender, const char *recipient,
                        int source_class, int trace_flags,
                        int utf8_flags, VSTRING *queue_id)
{
    VSTREAM *stream;

    if ((stream = mail_connect(MAIL_CLASS_PUBLIC, var_cleanup_service,
                   BLOCKING)) != 0)
    post_mail_init(stream, sender, recipient, source_class, trace_flags,
               utf8_flags, queue_id);
    else
    msg_warn("connect to %s/%s: %m",
         MAIL_CLASS_PUBLIC, var_cleanup_service);
    return (stream);
}

/* post_mail_open_event - handle asynchronous connection events */

static void post_mail_open_event(int event, void *context)
{
    POST_MAIL_STATE *state = (POST_MAIL_STATE *) context;
    const char *myname = "post_mail_open_event";

    switch (event) {

    /*
     * Initial server reply. Stop the watchdog timer, disable further
     * read events that end up calling this function, and notify the
     * requestor.
     */
    case EVENT_READ:
    if (msg_verbose)
        msg_info("%s: read event", myname);
    event_cancel_timer(post_mail_open_event, context);
    event_disable_readwrite(vstream_fileno(state->stream));
    non_blocking(vstream_fileno(state->stream), BLOCKING);
    post_mail_init(state->stream, state->sender,
               state->recipient, state->source_class,
               state->trace_flags, state->utf8_flags,
               state->queue_id);
    myfree(state->sender);
    myfree(state->recipient);
    state->notify(state->stream, state->context);
    myfree((void *) state);
    return;

    /*
     * No connection or no initial reply within a conservative time
     * limit. The system is broken and we give up.
     */
    case EVENT_TIME:
    if (state->stream) {
        msg_warn("timeout connecting to service: %s", var_cleanup_service);
        event_disable_readwrite(vstream_fileno(state->stream));
        vstream_fclose(state->stream);
    } else {
        msg_warn("connect to service: %s: %m", var_cleanup_service);
    }
    myfree(state->sender);
    myfree(state->recipient);
    state->notify((VSTREAM *) 0, state->context);
    myfree((void *) state);
    return;

    /*
     * Some exception.
     */
    case EVENT_XCPT:
    msg_warn("error connecting to service: %s", var_cleanup_service);
    event_cancel_timer(post_mail_open_event, context);
    event_disable_readwrite(vstream_fileno(state->stream));
    vstream_fclose(state->stream);
    myfree(state->sender);
    myfree(state->recipient);
    state->notify((VSTREAM *) 0, state->context);
    myfree((void *) state);
    return;

    /*
     * Broken software or hardware.
     */
    default:
    msg_panic("%s: unknown event type %d", myname, event);
    }
}

/* post_mail_fopen_async - prepare for posting a message */

void    post_mail_fopen_async(const char *sender, const char *recipient,
                          int source_class, int trace_flags,
                          int utf8_flags, VSTRING *queue_id,
                          void (*notify) (VSTREAM *, void *),
                          void *context)
{
    VSTREAM *stream;
    POST_MAIL_STATE *state;

    stream = mail_connect(MAIL_CLASS_PUBLIC, var_cleanup_service, NON_BLOCKING);
    state = (POST_MAIL_STATE *) mymalloc(sizeof(*state));
    state->sender = mystrdup(sender);
    state->recipient = mystrdup(recipient);
    state->source_class = source_class;
    state->trace_flags = trace_flags;
    state->utf8_flags = utf8_flags;
    state->notify = notify;
    state->context = context;
    state->stream = stream;
    state->queue_id = queue_id;

    /*
     * To keep interfaces as simple as possible we report all errors via the
     * same interface as all successes.
     */
    if (stream != 0) {
    event_enable_read(vstream_fileno(stream), post_mail_open_event,
              (void *) state);
    event_request_timer(post_mail_open_event, (void *) state,
                var_daemon_timeout);
    } else {
    event_request_timer(post_mail_open_event, (void *) state, 0);
    }
}

/* post_mail_fprintf - format and send message content */

int     post_mail_fprintf(VSTREAM *cleanup, const char *format,...)
{
    int     status;
    va_list ap;

    va_start(ap, format);
    status = rec_vfprintf(cleanup, REC_TYPE_NORM, format, ap);
    va_end(ap);
    return (status != REC_TYPE_NORM ? CLEANUP_STAT_WRITE : 0);
}

/* post_mail_buffer - send pre-formatted buffer */

int     post_mail_buffer(VSTREAM *cleanup, const char *buf, int len)
{
    return (rec_put(cleanup, REC_TYPE_NORM, buf, len) != REC_TYPE_NORM ?
        CLEANUP_STAT_WRITE : 0);
}

/* post_mail_fputs - send pre-formatted message content */

int     post_mail_fputs(VSTREAM *cleanup, const char *str)
{
    ssize_t len = str ? strlen(str) : 0;

    return (rec_put(cleanup, REC_TYPE_NORM, str, len) != REC_TYPE_NORM ?
        CLEANUP_STAT_WRITE : 0);
}

/* post_mail_fclose - finish posting of message */

int     post_mail_fclose(VSTREAM *cleanup)
{
    int     status = 0;

    /*
     * Send the message end marker only when there were no errors.
     */
    if (vstream_ferror(cleanup) != 0) {
    status = CLEANUP_STAT_WRITE;
    } else {
    rec_fputs(cleanup, REC_TYPE_XTRA, "");
    rec_fputs(cleanup, REC_TYPE_END, "");
    if (vstream_fflush(cleanup)
        || attr_scan(cleanup, ATTR_FLAG_MISSING,
             RECV_ATTR_INT(MAIL_ATTR_STATUS, &status),
             ATTR_TYPE_END) != 1)
        status = CLEANUP_STAT_WRITE;
    }
    (void) vstream_fclose(cleanup);
    return (status);
}

/* post_mail_fclose_event - event handler */

static void post_mail_fclose_event(int event, void *context)
{
    POST_MAIL_FCLOSE_STATE *state = (POST_MAIL_FCLOSE_STATE *) context;
    int     status = state->status;

    switch (event) {

    /*
     * Final server reply. Pick up the completion status.
     */
    case EVENT_READ:
    if (status == 0) {
        if (vstream_ferror(state->stream) != 0
        || attr_scan(state->stream, ATTR_FLAG_MISSING,
                 ATTR_TYPE_INT, MAIL_ATTR_STATUS, &status,
                 ATTR_TYPE_END) != 1)
        status = CLEANUP_STAT_WRITE;
    }
    break;

    /*
     * No response or error.
     */
    default:
    msg_warn("error talking to service: %s", var_cleanup_service);
    status = CLEANUP_STAT_WRITE;
    break;
    }

    /*
     * Stop the watchdog timer, and disable further read events that end up
     * calling this function.
     */
    event_cancel_timer(post_mail_fclose_event, context);
    event_disable_readwrite(vstream_fileno(state->stream));

    /*
     * Notify the requestor and clean up.
     */
    state->notify(status, state->context);
    (void) vstream_fclose(state->stream);
    myfree((void *) state);
}

/* post_mail_fclose_async - finish posting of message */

void    post_mail_fclose_async(VSTREAM *stream,
                     void (*notify) (int status, void *context),
                           void *context)
{
    POST_MAIL_FCLOSE_STATE *state;
    int     status = 0;


    /*
     * Send the message end marker only when there were no errors.
     */
    if (vstream_ferror(stream) != 0) {
    status = CLEANUP_STAT_WRITE;
    } else {
    rec_fputs(stream, REC_TYPE_XTRA, "");
    rec_fputs(stream, REC_TYPE_END, "");
    if (vstream_fflush(stream))
        status = CLEANUP_STAT_WRITE;
    }

    /*
     * Bundle up the suspended state.
     */
    state = (POST_MAIL_FCLOSE_STATE *) mymalloc(sizeof(*state));
    state->status = status;
    state->stream = stream;
    state->notify = notify;
    state->context = context;

    /*
     * To keep interfaces as simple as possible we report all errors via the
     * same interface as all successes.
     */
    if (status == 0) {
    event_enable_read(vstream_fileno(stream), post_mail_fclose_event,
              (void *) state);
    event_request_timer(post_mail_fclose_event, (void *) state,
                var_daemon_timeout);
    } else {
    event_request_timer(post_mail_fclose_event, (void *) state, 0);
    }
}