1/* 2 * Copyright (c) 1983 Regents of the University of California. 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 3. All advertising materials mentioning features or use of this software 14 * must display the following acknowledgement: 15 * This product includes software developed by the University of 16 * California, Berkeley and its contributors. 17 * 4. Neither the name of the University nor the names of its contributors 18 * may be used to endorse or promote products derived from this software 19 * without specific prior written permission. 20 * 21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 24 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 31 * SUCH DAMAGE. 32 */ 33 34#ifndef lint 35/*static char sccsid[] = "from: @(#)tftpsubs.c 5.6 (Berkeley) 2/28/91";*/ 36/* static char rcsid[] = "$Id: tftpsubs.c,v 1.2 1993/08/01 18:07:04 mycroft Exp $"; */ 37#endif /* not lint */ 38 39/* Simple minded read-ahead/write-behind subroutines for tftp user and 40 server. Written originally with multiple buffers in mind, but current 41 implementation has two buffer logic wired in. 42 43 Todo: add some sort of final error check so when the write-buffer 44 is finally flushed, the caller can detect if the disk filled up 45 (or had an i/o error) and return a nak to the other side. 46 47 Jim Guyton 10/85 48 */ 49 50#include <sys/types.h> 51#include <sys/socket.h> 52#include <sys/ioctl.h> 53#include <netinet/in.h> 54#include <unistd.h> 55#include <stdio.h> 56 57#include "tftp.h" 58 59#define PKTSIZE SEGSIZE+4 /* should be moved to tftp.h */ 60 61struct bf { 62 int counter; /* size of data in buffer, or flag */ 63 char buf[PKTSIZE]; /* room for data packet */ 64} bfs[2]; 65 66 /* Values for bf.counter */ 67#define BF_ALLOC -3 /* alloc'd but not yet filled */ 68#define BF_FREE -2 /* free */ 69/* [-1 .. SEGSIZE] = size of data in the data buffer */ 70 71static int nextone; /* index of next buffer to use */ 72static int current; /* index of buffer in use */ 73 74 /* control flags for crlf conversions */ 75int newline = 0; /* fillbuf: in middle of newline expansion */ 76int prevchar = -1; /* putbuf: previous char (cr check) */ 77 78struct tftphdr *rw_init(int); 79 80struct tftphdr *w_init() { return rw_init(0); } /* write-behind */ 81struct tftphdr *r_init() { return rw_init(1); } /* read-ahead */ 82 83/* init for either read-ahead or write-behind */ 84/* x is zero for write-behind, one for read-head */ 85struct tftphdr *rw_init(int x) 86{ 87 newline = 0; /* init crlf flag */ 88 prevchar = -1; 89 bfs[0].counter = BF_ALLOC; /* pass out the first buffer */ 90 current = 0; 91 bfs[1].counter = BF_FREE; 92 nextone = x; /* ahead or behind? */ 93 return (struct tftphdr *)bfs[0].buf; 94} 95 96 97/* Have emptied current buffer by sending to net and getting ack. 98 Free it and return next buffer filled with data. 99 */ 100int readit(FILE * file, struct tftphdr **dpp, int convert) 101{ 102 struct bf *b; 103 104 bfs[current].counter = BF_FREE; /* free old one */ 105 current = !current; /* "incr" current */ 106 107 b = &bfs[current]; /* look at new buffer */ 108 if (b->counter == BF_FREE) /* if it's empty */ 109 read_ahead(file, convert); /* fill it */ 110#if 0 111 assert(b->counter != BF_FREE); /* check */ 112#endif 113 *dpp = (struct tftphdr *)b->buf; /* set caller's ptr */ 114 return b->counter; 115} 116 117/* 118 * fill the input buffer, doing ascii conversions if requested 119 * conversions are lf -> cr,lf and cr -> cr, nul 120 */ 121void read_ahead(FILE *file, int convert) 122{ 123 register int i; 124 register char *p; 125 register int c; 126 struct bf *b; 127 struct tftphdr *dp; 128 129 b = &bfs[nextone]; /* look at "next" buffer */ 130 if (b->counter != BF_FREE) /* nop if not free */ 131 return; 132 nextone = !nextone; /* "incr" next buffer ptr */ 133 134 dp = (struct tftphdr *)b->buf; 135 136 if (convert == 0) { 137 b->counter = read(fileno(file), dp->th_data, SEGSIZE); 138 return; 139 } 140 141 p = dp->th_data; 142 for (i = 0 ; i < SEGSIZE; i++) { 143 if (newline) { 144 if (prevchar == '\n') 145 c = '\n'; /* lf to cr,lf */ 146 else c = '\0'; /* cr to cr,nul */ 147 newline = 0; 148 } 149 else { 150 c = getc(file); 151 if (c == EOF) break; 152 if (c == '\n' || c == '\r') { 153 prevchar = c; 154 c = '\r'; 155 newline = 1; 156 } 157 } 158 *p++ = c; 159 } 160 b->counter = (int)(p - dp->th_data); 161} 162 163/* Update count associated with the buffer, get new buffer 164 from the queue. Calls write_behind only if next buffer not 165 available. 166 */ 167int writeit(FILE *file, struct tftphdr **dpp, int ct, int convert) 168{ 169 bfs[current].counter = ct; /* set size of data to write */ 170 current = !current; /* switch to other buffer */ 171 if (bfs[current].counter != BF_FREE) /* if not free */ 172 write_behind(file, convert); /* flush it */ 173 bfs[current].counter = BF_ALLOC; /* mark as alloc'd */ 174 *dpp = (struct tftphdr *)bfs[current].buf; 175 return ct; /* this is a lie of course */ 176} 177 178/* 179 * Output a buffer to a file, converting from netascii if requested. 180 * CR,NUL -> CR and CR,LF => LF. 181 * Note spec is undefined if we get CR as last byte of file or a 182 * CR followed by anything else. In this case we leave it alone. 183 */ 184int write_behind(FILE *file, int convert) 185{ 186 char *buf; 187 int count; 188 register int ct; 189 register char *p; 190 register int c; /* current character */ 191 struct bf *b; 192 struct tftphdr *dp; 193 194 b = &bfs[nextone]; 195 if (b->counter < -1) /* anything to flush? */ 196 return 0; /* just nop if nothing to do */ 197 198 count = b->counter; /* remember byte count */ 199 b->counter = BF_FREE; /* reset flag */ 200 dp = (struct tftphdr *)b->buf; 201 nextone = !nextone; /* incr for next time */ 202 buf = dp->th_data; 203 204 if (count <= 0) return -1; /* nak logic? */ 205 206 if (convert == 0) 207 return write(fileno(file), buf, count); 208 209 p = buf; 210 ct = count; 211 while (ct--) { /* loop over the buffer */ 212 c = *p++; /* pick up a character */ 213 if (prevchar == '\r') { /* if prev char was cr */ 214 if (c == '\n') /* if have cr,lf then just */ 215 fseek(file, -1, 1); /* smash lf on top of the cr */ 216 else 217 if (c == '\0') /* if have cr,nul then */ 218 goto skipit; /* just skip over the putc */ 219 /* else just fall through and allow it */ 220 } 221 putc(c, file); 222skipit: 223 prevchar = c; 224 } 225 return count; 226} 227 228 229/* When an error has occurred, it is possible that the two sides 230 * are out of synch. Ie: that what I think is the other side's 231 * response to packet N is really their response to packet N-1. 232 * 233 * So, to try to prevent that, we flush all the input queued up 234 * for us on the network connection on our host. 235 * 236 * We return the number of packets we flushed (mostly for reporting 237 * when trace is active). 238 */ 239 240int synchnet(int f) 241{ 242 int j = 0; 243 char dummy; 244 245 while (1) { 246 if (recv(f, &dummy, 1, MSG_DONTWAIT) < 0) 247 break; 248 j++; 249 } 250 return j; 251} 252