mail_command_client.c

[詳解]

/*++
/* NAME
/*  mail_command_client 3
/* SUMMARY
/*  single-command client
/* SYNOPSIS
/*  #include <mail_proto.h>
/*
/*  int mail_command_client(class, name, type, attr, ...)
/*  const char *class;
/*  const char *name;
/*  int type;
/*  const char *attr;
/* DESCRIPTION
/*  This module implements a client interface for single-command
/*  clients: a client that sends a single command and expects
/*  a single completion status code.
/*
/*  Arguments:
/* .IP class
/*  Service type: MAIL_CLASS_PUBLIC or MAIL_CLASS_PRIVATE
/* .IP name
/*  Service name (master.cf).
/* .IP "type, attr, ..."
/*  Attribute information as defined in attr_print(3).
/* DIAGNOSTICS
/*  The result is -1 if the request could not be sent, otherwise
/*  the result is the status reported by the server.
/*  Warnings: problems connecting to the requested service.
/*  Fatal: out of memory.
/* SEE ALSO
/*  attr_print(3), send attributes over byte stream
/*  mail_command_server(3), server interface
/*  mail_proto(3h), client-server protocol
/* 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 <stdlib.h>         /* 44BSD stdarg.h uses abort() */
#include <stdarg.h>

/* Utility library. */

#include <vstream.h>
#include <msg.h>

/* Global library. */

#include <mail_proto.h>

/* mail_command_client - single-command transaction with completion status */

int     mail_command_client(const char *class, const char *name,...)
{
    va_list ap;
    VSTREAM *stream;
    int     status;

    /*
     * Talk a little protocol with the specified service.
     * 
     * This function is used for non-critical services where it is OK to back
     * off after the first error. Log what communication stage failed, to
     * facilitate trouble analysis.
     */
    if ((stream = mail_connect(class, name, BLOCKING)) == 0) {
    msg_warn("connect to %s/%s: %m", class, name);
    return (-1);
    }
    va_start(ap, name);
    status = attr_vprint(stream, ATTR_FLAG_NONE, ap);
    va_end(ap);
    if (status != 0) {
    msg_warn("write %s: %m", VSTREAM_PATH(stream));
    status = -1;
    } else if (attr_scan(stream, ATTR_FLAG_STRICT,
             RECV_ATTR_INT(MAIL_ATTR_STATUS, &status), 0) != 1) {
    msg_warn("write/read %s: %m", VSTREAM_PATH(stream));
    status = -1;
    }
    (void) vstream_fclose(stream);
    return (status);
}