timed_connect.c

[詳解]

/*++
/* NAME
/*  timed_connect 3
/* SUMMARY
/*  connect operation with timeout
/* SYNOPSIS
/*  #include <sys/socket.h>
/*  #include <timed_connect.h>
/*
/*  int timed_connect(fd, buf, buf_len, timeout)
/*  int fd;
/*  struct sockaddr *buf;
/*  int buf_len;
/*  int timeout;
/* DESCRIPTION
/*  timed_connect() implement a BSD socket connect() operation that is
/*  bounded in time.
/*
/*  Arguments:
/* .IP fd
/*  File descriptor in the range 0..FD_SETSIZE. This descriptor
/*  must be set to non-blocking mode prior to calling timed_connect().
/* .IP buf
/*  Socket address buffer pointer.
/* .IP buf_len
/*  Size of socket address buffer.
/* .IP timeout
/*  The deadline in seconds. This must be a number > 0.
/* DIAGNOSTICS
/*  Panic: interface violations.
/*  When the operation does not complete within the deadline, the
/*  result value is -1, and errno is set to ETIMEDOUT.
/*  All other returns are identical to those of a blocking connect(2)
/*  operation.
/* WARNINGS
/* .ad
/* .fi
/*  A common error is to call timed_connect() without enabling
/*  non-blocking I/O on the socket. In that case, the \fItimeout\fR
/*  parameter takes no effect.
/* 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/socket.h>
#include <errno.h>

/* Utility library. */

#include "msg.h"
#include "iostuff.h"
#include "sane_connect.h"
#include "timed_connect.h"

/* timed_connect - connect with deadline */

int     timed_connect(int sock, struct sockaddr *sa, int len, int timeout)
{
    int     error;
    SOCKOPT_SIZE error_len;

    /*
     * Sanity check. Just like with timed_wait(), the timeout must be a
     * positive number.
     */
    if (timeout <= 0)
    msg_panic("timed_connect: bad timeout: %d", timeout);

    /*
     * Start the connection, and handle all possible results.
     */
    if (sane_connect(sock, sa, len) == 0)
    return (0);
    if (errno != EINPROGRESS)
    return (-1);

    /*
     * A connection is in progress. Wait for a limited amount of time for
     * something to happen. If nothing happens, report an error.
     */
    if (write_wait(sock, timeout) < 0)
    return (-1);

    /*
     * Something happened. Some Solaris 2 versions have getsockopt() itself
     * return the error, instead of returning it via the parameter list.
     */
    error = 0;
    error_len = sizeof(error);
    if (getsockopt(sock, SOL_SOCKET, SO_ERROR, (void *) &error, &error_len) < 0)
    return (-1);
    if (error) {
    errno = error;
    return (-1);
    }

    /*
     * No problems.
     */
    return (0);
}