mail_trigger.c

[詳解]

/*++
/* NAME
/*  mail_trigger 3
/* SUMMARY
/*  trigger a mail service
/* SYNOPSIS
/*  #include <mail_proto.h>
/*
/*  int mail_trigger(class, service, request, length)
/*  const char *class;
/*  const char *service;
/*  const char *request;
/*  ssize_t length;
/* DESCRIPTION
/*  mail_trigger() wakes up the specified mail subsystem, by
/*  sending it the specified request. In the case of non-FIFO
/*  server endpoints, a short-running program should invoke
/*  event_drain() to ensure proper request delivery.
/*
/*  Arguments:
/* .IP class
/*  Name of a class of local transport channel endpoints,
/*  either \fIpublic\fR (accessible by any local user) or
/*  \fIprivate\fR (administrative access only).
/* .IP service
/*  The name of a local transport endpoint within the named class.
/* .IP request
/*  A string. The list of valid requests is service specific.
/* .IP length
/*  The length of the request string.
/* DIAGNOSTICS
/*  The result is -1 in case of problems, 0 otherwise.
/*  Warnings are logged.
/* BUGS
/*  Works with FIFO or UNIX-domain services only.
/*
/*  Should use master.cf to find out what transport to use.
/* SEE ALSO
/*  fifo_trigger(3) trigger a FIFO-based service
/*  unix_trigger(3) trigger a UNIX_domain 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
/*--*/

/* System library. */

#include <sys_defs.h>
#include <sys/stat.h>

/* Utility library. */

#include <msg.h>
#include <mymalloc.h>
#include <iostuff.h>
#include <trigger.h>
#include <warn_stat.h>

/* Global library. */

#include "mail_params.h"
#include "mail_proto.h"

/* mail_trigger - trigger a service */

int     mail_trigger(const char *class, const char *service,
                     const char *req_buf, ssize_t req_len)
{
    struct stat st;
    char   *path;
    int     status;

    /*
     * XXX Some systems cannot tell the difference between a named pipe
     * (fifo) or a UNIX-domain socket. So we may have to try both.
     */
    path = mail_pathname(class, service);
    if ((status = stat(path, &st)) < 0) {
     msg_warn("unable to look up %s: %m", path);
    } else if (S_ISFIFO(st.st_mode)) {
    status = fifo_trigger(path, req_buf, req_len, var_trigger_timeout);
    if (status < 0 && S_ISSOCK(st.st_mode))
        status = LOCAL_TRIGGER(path, req_buf, req_len, var_trigger_timeout);
    } else if (S_ISSOCK(st.st_mode)) {
    status = LOCAL_TRIGGER(path, req_buf, req_len, var_trigger_timeout);
    } else {
    msg_warn("%s is not a socket or a fifo", path);
    status = -1;
    }
    myfree(path);
    return (status);
}