pass_accept.c

[詳解]

/*++
/* NAME
/*  pass_accept 3
/* SUMMARY
/*  start UNIX-domain file descriptor listener
/* SYNOPSIS
/*  #include <listen.h>
/*
/*  int pass_accept(listen_fd)
/*  int listen_fd;
/*
/*  int pass_accept_attr(listen_fd, attr)
/*  int listen_fd;
/*  HTABLE  **attr;
/* DESCRIPTION
/*  This module implements a listener that receives one attribute list
/*  and file descriptor over each a local connection that is made to it.
/*
/*  Arguments:
/* .IP attr
/*  Pointer to attribute list pointer.  In case of error, or
/*  no attributes, the attribute list pointer is set to null.
/* .IP listen_fd
/*  File descriptor returned by LOCAL_LISTEN().
/* DIAGNOSTICS
/*  Warnings: I/O errors, timeout.
/* 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 <errno.h>
#include <unistd.h>

/* Utility library. */

#include <msg.h>
#include <listen.h>
#include <attr.h>

#define PASS_ACCEPT_TMOUT   100

/* pass_accept - accept descriptor */

int     pass_accept(int listen_fd)
{
    const char *myname = "pass_accept";
    int     accept_fd;
    int     recv_fd = -1;

    accept_fd = LOCAL_ACCEPT(listen_fd);
    if (accept_fd < 0) {
    if (errno != EAGAIN)
        msg_warn("%s: cannot accept connection: %m", myname);
    return (-1);
    } else {
    if (read_wait(accept_fd, PASS_ACCEPT_TMOUT) < 0)
        msg_warn("%s: timeout receiving file descriptor: %m", myname);
    else if ((recv_fd = LOCAL_RECV_FD(accept_fd)) < 0)
        msg_warn("%s: cannot receive file descriptor: %m", myname);
    if (close(accept_fd) < 0)
        msg_warn("%s: close: %m", myname);
    return (recv_fd);
    }
}

/* pass_accept_attr - accept descriptor and attribute list */

int     pass_accept_attr(int listen_fd, HTABLE **attr)
{
    const char *myname = "pass_accept_attr";
    int     accept_fd;
    int     recv_fd = -1;

    *attr = 0;
    accept_fd = LOCAL_ACCEPT(listen_fd);
    if (accept_fd < 0) {
    if (errno != EAGAIN)
        msg_warn("%s: cannot accept connection: %m", myname);
    return (-1);
    } else {
    if (read_wait(accept_fd, PASS_ACCEPT_TMOUT) < 0)
        msg_warn("%s: timeout receiving file descriptor: %m", myname);
    else if ((recv_fd = LOCAL_RECV_FD(accept_fd)) < 0)
        msg_warn("%s: cannot receive file descriptor: %m", myname);
    else if (read_wait(accept_fd, PASS_ACCEPT_TMOUT) < 0
         || recv_pass_attr(accept_fd, attr, PASS_ACCEPT_TMOUT, 0) < 0) {
        msg_warn("%s: cannot receive connection attributes: %m", myname);
        if (close(recv_fd) < 0)
        msg_warn("%s: close: %m", myname);
        recv_fd = -1;
    }
    if (close(accept_fd) < 0)
        msg_warn("%s: close: %m", myname);
    return (recv_fd);
    }
}