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/* $OpenBSD: tftpsubs.c,v 1.15 2012/05/01 04:23:21 gsoares Exp $ */ |
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/* $NetBSD: tftpsubs.c,v 1.3 1994/12/08 09:51:31 jtc Exp $ */ |
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/* |
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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. 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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/* |
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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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* |
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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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* |
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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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/* 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 struct tftphdr *rw_init(int); |
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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[SEGSIZE_MAX + 4]; /* room for data packet */ |
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} bfs[2]; |
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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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struct tftphdr * |
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w_init(void) |
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{ |
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return (rw_init(0)); /* write-behind */ |
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} |
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struct tftphdr * |
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r_init(void) |
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{ |
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return (rw_init(1)); /* read-ahead */ |
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} |
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/* |
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* Init for either read-ahead or write-behind. |
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* Zero for write-behind, one for read-head. |
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*/ |
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static struct tftphdr * |
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rw_init(int x) |
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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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/* |
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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 *file, struct tftphdr **dpp, int convert, int segment_size) |
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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, segment_size); /* 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 *file, int convert, int segment_size) |
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{ |
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int i; |
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char *p; |
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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, segment_size); |
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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 < segment_size; 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 |
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c = '\0'; /* cr to cr, nul */ |
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newline = 0; |
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} else { |
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c = getc(file); |
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if (c == EOF) |
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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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/* |
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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 *file, struct tftphdr **dpp, int ct, int 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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/* flush it */ |
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(void)write_behind(file, convert); |
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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 *file, int convert) |
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{ |
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char *buf; |
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int count; |
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int ct; |
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char *p; |
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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) /* nak logic? */ |
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return (-1); |
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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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/* smash lf on top of the cr */ |
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fseek(file, -1, SEEK_CUR); |
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else if (c == '\0') /* if have cr,nul then */ |
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goto skipit; /* just skip over the putc */ |
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/* FALLTHROUGH */ |
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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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/* |
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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(int f) |
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{ |
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int i, j = 0; |
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char rbuf[SEGSIZE_MIN]; |
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struct sockaddr_storage from; |
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socklen_t fromlen; |
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for (;;) { |
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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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} |