1/* 2 * Copyright (c) 1983, 1993 3 * The Regents of the University of California. 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#include <sys/cdefs.h> 35 36__FBSDID("$FreeBSD: src/usr.bin/tftp/tftpsubs.c,v 1.6 2005/02/14 17:42:58 stefanf Exp $"); 37 38#ifndef lint 39static const char sccsid[] = "@(#)tftpsubs.c 8.1 (Berkeley) 6/6/93"; 40#endif 41 42/* Simple minded read-ahead/write-behind subroutines for tftp user and 43 server. Written originally with multiple buffers in mind, but current 44 implementation has two buffer logic wired in. 45 46 Todo: add some sort of final error check so when the write-buffer 47 is finally flushed, the caller can detect if the disk filled up 48 (or had an i/o error) and return a nak to the other side. 49 50 Jim Guyton 10/85 51 */ 52 53#include <sys/types.h> 54#include <sys/socket.h> 55#include <sys/ioctl.h> 56#include <netinet/in.h> 57#include <arpa/tftp.h> 58 59#include <stdio.h> 60#include <unistd.h> 61 62#include "tftpsubs.h" 63 64#ifdef __APPLE__ 65struct bf { 66 int counter; /* size of data in buffer, or flag */ 67 char buf[MAXPKTSIZE]; /* room for data packet */ 68} bfs[2]; 69#else 70#define PKTSIZE SEGSIZE+4 /* should be moved to tftp.h */ 71 72struct bf { 73 int counter; /* size of data in buffer, or flag */ 74 char buf[PKTSIZE]; /* room for data packet */ 75} bfs[2]; 76#endif 77 78 /* Values for bf.counter */ 79#define BF_ALLOC -3 /* alloc'd but not yet filled */ 80#define BF_FREE -2 /* free */ 81/* [-1 .. SEGSIZE] = size of data in the data buffer */ 82 83static int nextone; /* index of next buffer to use */ 84static int current; /* index of buffer in use */ 85 86 /* control flags for crlf conversions */ 87int newline = 0; /* fillbuf: in middle of newline expansion */ 88int prevchar = -1; /* putbuf: previous char (cr check) */ 89 90static struct tftphdr *rw_init(int); 91 92struct tftphdr *w_init(void) { return rw_init(0); } /* write-behind */ 93struct tftphdr *r_init(void) { return rw_init(1); } /* read-ahead */ 94 95static struct tftphdr * 96rw_init(x) /* init for either read-ahead or write-behind */ 97 int x; /* zero for write-behind, one for read-head */ 98{ 99 newline = 0; /* init crlf flag */ 100 prevchar = -1; 101 bfs[0].counter = BF_ALLOC; /* pass out the first buffer */ 102 current = 0; 103 bfs[1].counter = BF_FREE; 104 nextone = x; /* ahead or behind? */ 105 return (struct tftphdr *)bfs[0].buf; 106} 107 108 109/* Have emptied current buffer by sending to net and getting ack. 110 Free it and return next buffer filled with data. 111 */ 112int 113readit(file, dpp, amt, convert) 114 FILE *file; /* file opened for read */ 115 struct tftphdr **dpp; 116 int amt; 117 int convert; /* if true, convert to ascii */ 118{ 119 struct bf *b; 120 121 bfs[current].counter = BF_FREE; /* free old one */ 122 current = !current; /* "incr" current */ 123 124 b = &bfs[current]; /* look at new buffer */ 125 if (b->counter == BF_FREE) /* if it's empty */ 126 read_ahead(file, amt, convert); /* fill it */ 127/* assert(b->counter != BF_FREE);*//* check */ 128 *dpp = (struct tftphdr *)b->buf; /* set caller's ptr */ 129 return b->counter; 130} 131 132/* 133 * fill the input buffer, doing ascii conversions if requested 134 * conversions are lf -> cr,lf and cr -> cr, nul 135 */ 136void 137read_ahead(file, amt, convert) 138 FILE *file; /* file opened for read */ 139 int amt; /* number of bytes to read */ 140 int convert; /* if true, convert to ascii */ 141{ 142 int i; 143 char *p; 144 int c; 145 struct bf *b; 146 struct tftphdr *dp; 147 148 b = &bfs[nextone]; /* look at "next" buffer */ 149 if (b->counter != BF_FREE) /* nop if not free */ 150 return; 151 nextone = !nextone; /* "incr" next buffer ptr */ 152 153 dp = (struct tftphdr *)b->buf; 154 155 if (convert == 0) { 156 b->counter = read(fileno(file), dp->th_data, amt); 157 return; 158 } 159 160 p = dp->th_data; 161 for (i = 0 ; i < amt; i++) { 162 if (newline) { 163 if (prevchar == '\n') 164 c = '\n'; /* lf to cr,lf */ 165 else c = '\0'; /* cr to cr,nul */ 166 newline = 0; 167 } 168 else { 169 c = getc(file); 170 if (c == EOF) break; 171 if (c == '\n' || c == '\r') { 172 prevchar = c; 173 c = '\r'; 174 newline = 1; 175 } 176 } 177 *p++ = c; 178 } 179 b->counter = (int)(p - dp->th_data); 180} 181 182/* Update count associated with the buffer, get new buffer 183 from the queue. Calls write_behind only if next buffer not 184 available. 185 */ 186int 187writeit(file, dpp, ct, convert) 188 FILE *file; 189 struct tftphdr **dpp; 190 int ct, convert; 191{ 192 bfs[current].counter = ct; /* set size of data to write */ 193 current = !current; /* switch to other buffer */ 194 if (bfs[current].counter != BF_FREE) /* if not free */ 195 (void)write_behind(file, convert); /* flush it */ 196 bfs[current].counter = BF_ALLOC; /* mark as alloc'd */ 197 *dpp = (struct tftphdr *)bfs[current].buf; 198 return ct; /* this is a lie of course */ 199} 200 201/* 202 * Output a buffer to a file, converting from netascii if requested. 203 * CR,NUL -> CR and CR,LF => LF. 204 * Note spec is undefined if we get CR as last byte of file or a 205 * CR followed by anything else. In this case we leave it alone. 206 */ 207int 208write_behind(file, convert) 209 FILE *file; 210 int convert; 211{ 212 char *buf; 213 int count; 214 int ct; 215 char *p; 216 int c; /* current character */ 217 struct bf *b; 218 struct tftphdr *dp; 219 220 b = &bfs[nextone]; 221 if (b->counter < -1) /* anything to flush? */ 222 return 0; /* just nop if nothing to do */ 223 224 count = b->counter; /* remember byte count */ 225 b->counter = BF_FREE; /* reset flag */ 226 dp = (struct tftphdr *)b->buf; 227 nextone = !nextone; /* incr for next time */ 228 buf = dp->th_data; 229 230 if (count <= 0) return -1; /* nak logic? */ 231 232 if (convert == 0) 233 return write(fileno(file), buf, count); 234 235 p = buf; 236 ct = count; 237 while (ct--) { /* loop over the buffer */ 238 c = *p++; /* pick up a character */ 239 if (prevchar == '\r') { /* if prev char was cr */ 240 if (c == '\n') /* if have cr,lf then just */ 241 fseek(file, -1, 1); /* smash lf on top of the cr */ 242 else 243 if (c == '\0') /* if have cr,nul then */ 244 goto skipit; /* just skip over the putc */ 245 /* else just fall through and allow it */ 246 } 247 putc(c, file); 248skipit: 249 prevchar = c; 250 } 251 return count; 252} 253 254 255/* When an error has occurred, it is possible that the two sides 256 * are out of synch. Ie: that what I think is the other side's 257 * response to packet N is really their response to packet N-1. 258 * 259 * So, to try to prevent that, we flush all the input queued up 260 * for us on the network connection on our host. 261 * 262 * We return the number of packets we flushed (mostly for reporting 263 * when trace is active). 264 */ 265 266int 267synchnet(f) 268 int f; /* socket to flush */ 269{ 270 int i, j = 0; 271 char rbuf[PKTSIZE]; 272 struct sockaddr_storage from; 273 socklen_t fromlen; 274 275 while (1) { 276 (void) ioctl(f, FIONREAD, &i); 277 if (i) { 278 j++; 279 fromlen = sizeof from; 280 (void) recvfrom(f, rbuf, sizeof (rbuf), 0, 281 (struct sockaddr *)&from, &fromlen); 282 } else { 283 return(j); 284 } 285 } 286} 287