/* -*- mode: c; c-basic-offset: 4; indent-tabs-mode: nil -*- */
/* lib/krb5/os/net_write.c */
/*
 * Copyright 1987, 1988, 1990, 2009 by the Massachusetts Institute of
 * Technology.  All Rights Reserved.
 *
 * Export of this software from the United States of America may
 *   require a specific license from the United States Government.
 *   It is the responsibility of any person or organization contemplating
 *   export to obtain such a license before exporting.
 *
 * WITHIN THAT CONSTRAINT, permission to use, copy, modify, and
 * distribute this software and its documentation for any purpose and
 * without fee is hereby granted, provided that the above copyright
 * notice appear in all copies and that both that copyright notice and
 * this permission notice appear in supporting documentation, and that
 * the name of M.I.T. not be used in advertising or publicity pertaining
 * to distribution of the software without specific, written prior
 * permission.  Furthermore if you modify this software you must label
 * your software as modified software and not distribute it in such a
 * fashion that it might be confused with the original M.I.T. software.
 * M.I.T. makes no representations about the suitability of
 * this software for any purpose.  It is provided "as is" without express
 * or implied warranty.
 */

#include "k5-int.h"
#include "os-proto.h"

/*
 * krb5_net_write() writes "len" bytes from "buf" to the file
 * descriptor "fd".  It returns the number of bytes written or
 * a write() error.  (The calling interface is identical to
 * write(2).)
 *
 * XXX must not use non-blocking I/O
 */

int
krb5_net_write(krb5_context context, int fd, const char *buf, int len)
{
    sg_buf sg;
    SG_SET(&sg, buf, len);
    return krb5int_net_writev(context, fd, &sg, 1);
}

int
krb5int_net_writev(krb5_context context, int fd, sg_buf *sgp, int nsg)
{
    ssize_t cc, len = 0;
    SOCKET_WRITEV_TEMP tmp;

    while (nsg > 0) {
        /* Skip any empty data blocks.  */
        if (SG_LEN(sgp) == 0) {
            sgp++, nsg--;
            continue;
        }
        cc = SOCKET_WRITEV((SOCKET)fd, sgp, nsg, tmp);
        if (cc < 0) {
            if (SOCKET_ERRNO == SOCKET_EINTR)
                continue;

            /* XXX this interface sucks! */
            errno = SOCKET_ERRNO;
            return -1;
        }
        len += cc;
        while (cc > 0) {
            if ((unsigned)cc < SG_LEN(sgp)) {
                SG_ADVANCE(sgp, (unsigned)cc);
                cc = 0;
            } else {
                cc -= SG_LEN(sgp);
                sgp++, nsg--;
                assert(nsg > 0 || cc == 0);
            }
        }
    }
    return len;
}