278 lines
8.3 KiB
C
278 lines
8.3 KiB
C
/*
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* Copyright (c) 1983, 1993
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* The Regents of the University of California. All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. All advertising materials mentioning features or use of this software
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* must display the following acknowledgement:
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* This product includes software developed by the University of
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* California, Berkeley and its contributors.
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* 4. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#ifndef lint
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#if 0
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static char sccsid[] = "@(#)tftpsubs.c 8.1 (Berkeley) 6/6/93";
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#endif
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static const char rcsid[] =
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"$Id$";
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#endif /* not lint */
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/* Simple minded read-ahead/write-behind subroutines for tftp user and
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server. Written originally with multiple buffers in mind, but current
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implementation has two buffer logic wired in.
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Todo: add some sort of final error check so when the write-buffer
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is finally flushed, the caller can detect if the disk filled up
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(or had an i/o error) and return a nak to the other side.
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Jim Guyton 10/85
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*/
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#include <sys/types.h>
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#include <sys/socket.h>
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#include <sys/ioctl.h>
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#include <netinet/in.h>
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#include <arpa/tftp.h>
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#include <stdio.h>
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#include <unistd.h>
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#include "tftpsubs.h"
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#define PKTSIZE SEGSIZE+4 /* should be moved to tftp.h */
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struct bf {
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int counter; /* size of data in buffer, or flag */
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char buf[PKTSIZE]; /* room for data packet */
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} bfs[2];
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/* Values for bf.counter */
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#define BF_ALLOC -3 /* alloc'd but not yet filled */
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#define BF_FREE -2 /* free */
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/* [-1 .. SEGSIZE] = size of data in the data buffer */
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static int nextone; /* index of next buffer to use */
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static int current; /* index of buffer in use */
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/* control flags for crlf conversions */
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int newline = 0; /* fillbuf: in middle of newline expansion */
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int prevchar = -1; /* putbuf: previous char (cr check) */
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static struct tftphdr *rw_init();
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struct tftphdr *w_init() { return rw_init(0); } /* write-behind */
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struct tftphdr *r_init() { return rw_init(1); } /* read-ahead */
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static struct tftphdr *
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rw_init(x) /* init for either read-ahead or write-behind */
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int x; /* zero for write-behind, one for read-head */
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{
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newline = 0; /* init crlf flag */
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prevchar = -1;
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bfs[0].counter = BF_ALLOC; /* pass out the first buffer */
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current = 0;
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bfs[1].counter = BF_FREE;
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nextone = x; /* ahead or behind? */
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return (struct tftphdr *)bfs[0].buf;
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}
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/* Have emptied current buffer by sending to net and getting ack.
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Free it and return next buffer filled with data.
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*/
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int
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readit(file, dpp, convert)
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FILE *file; /* file opened for read */
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struct tftphdr **dpp;
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int convert; /* if true, convert to ascii */
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{
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struct bf *b;
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bfs[current].counter = BF_FREE; /* free old one */
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current = !current; /* "incr" current */
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b = &bfs[current]; /* look at new buffer */
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if (b->counter == BF_FREE) /* if it's empty */
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read_ahead(file, convert); /* fill it */
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/* assert(b->counter != BF_FREE);*//* check */
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*dpp = (struct tftphdr *)b->buf; /* set caller's ptr */
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return b->counter;
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}
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/*
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* fill the input buffer, doing ascii conversions if requested
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* conversions are lf -> cr,lf and cr -> cr, nul
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*/
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void
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read_ahead(file, convert)
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FILE *file; /* file opened for read */
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int convert; /* if true, convert to ascii */
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{
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register int i;
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register char *p;
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register int c;
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struct bf *b;
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struct tftphdr *dp;
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b = &bfs[nextone]; /* look at "next" buffer */
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if (b->counter != BF_FREE) /* nop if not free */
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return;
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nextone = !nextone; /* "incr" next buffer ptr */
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dp = (struct tftphdr *)b->buf;
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if (convert == 0) {
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b->counter = read(fileno(file), dp->th_data, SEGSIZE);
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return;
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}
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p = dp->th_data;
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for (i = 0 ; i < SEGSIZE; i++) {
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if (newline) {
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if (prevchar == '\n')
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c = '\n'; /* lf to cr,lf */
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else c = '\0'; /* cr to cr,nul */
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newline = 0;
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}
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else {
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c = getc(file);
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if (c == EOF) break;
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if (c == '\n' || c == '\r') {
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prevchar = c;
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c = '\r';
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newline = 1;
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}
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}
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*p++ = c;
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}
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b->counter = (int)(p - dp->th_data);
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}
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/* Update count associated with the buffer, get new buffer
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from the queue. Calls write_behind only if next buffer not
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available.
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*/
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int
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writeit(file, dpp, ct, convert)
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FILE *file;
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struct tftphdr **dpp;
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int ct, convert;
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{
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bfs[current].counter = ct; /* set size of data to write */
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current = !current; /* switch to other buffer */
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if (bfs[current].counter != BF_FREE) /* if not free */
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(void)write_behind(file, convert); /* flush it */
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bfs[current].counter = BF_ALLOC; /* mark as alloc'd */
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*dpp = (struct tftphdr *)bfs[current].buf;
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return ct; /* this is a lie of course */
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}
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/*
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* Output a buffer to a file, converting from netascii if requested.
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* CR,NUL -> CR and CR,LF => LF.
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* Note spec is undefined if we get CR as last byte of file or a
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* CR followed by anything else. In this case we leave it alone.
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*/
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int
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write_behind(file, convert)
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FILE *file;
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int convert;
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{
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char *buf;
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int count;
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register int ct;
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register char *p;
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register int c; /* current character */
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struct bf *b;
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struct tftphdr *dp;
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b = &bfs[nextone];
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if (b->counter < -1) /* anything to flush? */
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return 0; /* just nop if nothing to do */
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count = b->counter; /* remember byte count */
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b->counter = BF_FREE; /* reset flag */
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dp = (struct tftphdr *)b->buf;
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nextone = !nextone; /* incr for next time */
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buf = dp->th_data;
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if (count <= 0) return -1; /* nak logic? */
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if (convert == 0)
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return write(fileno(file), buf, count);
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p = buf;
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ct = count;
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while (ct--) { /* loop over the buffer */
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c = *p++; /* pick up a character */
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if (prevchar == '\r') { /* if prev char was cr */
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if (c == '\n') /* if have cr,lf then just */
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fseek(file, -1, 1); /* smash lf on top of the cr */
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else
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if (c == '\0') /* if have cr,nul then */
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goto skipit; /* just skip over the putc */
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/* else just fall through and allow it */
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}
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putc(c, file);
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skipit:
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prevchar = c;
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}
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return count;
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}
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/* When an error has occurred, it is possible that the two sides
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* are out of synch. Ie: that what I think is the other side's
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* response to packet N is really their response to packet N-1.
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*
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* So, to try to prevent that, we flush all the input queued up
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* for us on the network connection on our host.
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*
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* We return the number of packets we flushed (mostly for reporting
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* when trace is active).
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*/
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int
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synchnet(f)
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int f; /* socket to flush */
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{
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int i, j = 0;
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char rbuf[PKTSIZE];
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struct sockaddr_in from;
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int fromlen;
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while (1) {
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(void) ioctl(f, FIONREAD, &i);
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if (i) {
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j++;
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fromlen = sizeof from;
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(void) recvfrom(f, rbuf, sizeof (rbuf), 0,
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(struct sockaddr *)&from, &fromlen);
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} else {
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return(j);
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}
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}
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}
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