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 39__attribute__((__used__)) 40static const char sccsid[] = "@(#)tftpsubs.c 8.1 (Berkeley) 6/6/93"; 41#endif 42 43/* Simple minded read-ahead/write-behind subroutines for tftp user and 44 server. Written originally with multiple buffers in mind, but current 45 implementation has two buffer logic wired in. 46 47 Todo: add some sort of final error check so when the write-buffer 48 is finally flushed, the caller can detect if the disk filled up 49 (or had an i/o error) and return a nak to the other side. 50 51 Jim Guyton 10/85 52 */ 53 54#include <sys/types.h> 55#include <sys/socket.h> 56#include <sys/ioctl.h> 57#include <netinet/in.h> 58#include <arpa/tftp.h> 59 60#include <stdio.h> 61#include <unistd.h> 62 63#include "tftpsubs.h" 64 65#ifdef __APPLE__ 66struct bf { 67 int counter; /* size of data in buffer, or flag */ 68 char buf[MAXPKTSIZE]; /* room for data packet */ 69} bfs[2]; 70#else 71#define PKTSIZE SEGSIZE+4 /* should be moved to tftp.h */ 72 73struct bf { 74 int counter; /* size of data in buffer, or flag */ 75 char buf[PKTSIZE]; /* room for data packet */ 76} bfs[2]; 77#endif 78 79 /* Values for bf.counter */ 80#define BF_ALLOC -3 /* alloc'd but not yet filled */ 81#define BF_FREE -2 /* free */ 82/* [-1 .. SEGSIZE] = size of data in the data buffer */ 83 84static int nextone; /* index of next buffer to use */ 85static int current; /* index of buffer in use */ 86 87 /* control flags for crlf conversions */ 88int newline = 0; /* fillbuf: in middle of newline expansion */ 89int prevchar = -1; /* putbuf: previous char (cr check) */ 90 91static struct tftphdr *rw_init(int); 92 93struct tftphdr *w_init(void) { return rw_init(0); } /* write-behind */ 94struct tftphdr *r_init(void) { return rw_init(1); } /* read-ahead */ 95 96static struct tftphdr * 97rw_init(x) /* init for either read-ahead or write-behind */ 98 int x; /* zero for write-behind, one for read-head */ 99{ 100 newline = 0; /* init crlf flag */ 101 prevchar = -1; 102 bfs[0].counter = BF_ALLOC; /* pass out the first buffer */ 103 current = 0; 104 bfs[1].counter = BF_FREE; 105 nextone = x; /* ahead or behind? */ 106 return (struct tftphdr *)bfs[0].buf; 107} 108 109 110/* Have emptied current buffer by sending to net and getting ack. 111 Free it and return next buffer filled with data. 112 */ 113int 114readit(file, dpp, amt, convert) 115 FILE *file; /* file opened for read */ 116 struct tftphdr **dpp; 117 int amt; 118 int convert; /* if true, convert to ascii */ 119{ 120 struct bf *b; 121 122 bfs[current].counter = BF_FREE; /* free old one */ 123 current = !current; /* "incr" current */ 124 125 b = &bfs[current]; /* look at new buffer */ 126 if (b->counter == BF_FREE) /* if it's empty */ 127 read_ahead(file, amt, convert); /* fill it */ 128/* assert(b->counter != BF_FREE);*//* check */ 129 *dpp = (struct tftphdr *)b->buf; /* set caller's ptr */ 130 return b->counter; 131} 132 133/* 134 * fill the input buffer, doing ascii conversions if requested 135 * conversions are lf -> cr,lf and cr -> cr, nul 136 */ 137void 138read_ahead(file, amt, convert) 139 FILE *file; /* file opened for read */ 140 int amt; /* number of bytes to read */ 141 int convert; /* if true, convert to ascii */ 142{ 143 int i; 144 char *p; 145 int c; 146 struct bf *b; 147 struct tftphdr *dp; 148 149 b = &bfs[nextone]; /* look at "next" buffer */ 150 if (b->counter != BF_FREE) /* nop if not free */ 151 return; 152 nextone = !nextone; /* "incr" next buffer ptr */ 153 154 dp = (struct tftphdr *)b->buf; 155 156 if (convert == 0) { 157 b->counter = read(fileno(file), dp->th_data, amt); 158 return; 159 } 160 161 p = dp->th_data; 162 for (i = 0 ; i < amt; i++) { 163 if (newline) { 164 if (prevchar == '\n') 165 c = '\n'; /* lf to cr,lf */ 166 else c = '\0'; /* cr to cr,nul */ 167 newline = 0; 168 } 169 else { 170 c = getc(file); 171 if (c == EOF) break; 172 if (c == '\n' || c == '\r') { 173 prevchar = c; 174 c = '\r'; 175 newline = 1; 176 } 177 } 178 *p++ = c; 179 } 180 b->counter = (int)(p - dp->th_data); 181} 182 183/* Update count associated with the buffer, get new buffer 184 from the queue. Calls write_behind only if next buffer not 185 available. 186 */ 187int 188writeit(file, dpp, ct, convert) 189 FILE *file; 190 struct tftphdr **dpp; 191 int ct, convert; 192{ 193 bfs[current].counter = ct; /* set size of data to write */ 194 current = !current; /* switch to other buffer */ 195 if (bfs[current].counter != BF_FREE) /* if not free */ 196 (void)write_behind(file, convert); /* flush it */ 197 bfs[current].counter = BF_ALLOC; /* mark as alloc'd */ 198 *dpp = (struct tftphdr *)bfs[current].buf; 199 return ct; /* this is a lie of course */ 200} 201 202/* 203 * Output a buffer to a file, converting from netascii if requested. 204 * CR,NUL -> CR and CR,LF => LF. 205 * Note spec is undefined if we get CR as last byte of file or a 206 * CR followed by anything else. In this case we leave it alone. 207 */ 208int 209write_behind(file, convert) 210 FILE *file; 211 int convert; 212{ 213 char *buf; 214 int count; 215 int ct; 216 char *p; 217 int c; /* current character */ 218 struct bf *b; 219 struct tftphdr *dp; 220 221 b = &bfs[nextone]; 222 if (b->counter < -1) /* anything to flush? */ 223 return 0; /* just nop if nothing to do */ 224 225 count = b->counter; /* remember byte count */ 226 b->counter = BF_FREE; /* reset flag */ 227 dp = (struct tftphdr *)b->buf; 228 nextone = !nextone; /* incr for next time */ 229 buf = dp->th_data; 230 231 if (count <= 0) return -1; /* nak logic? */ 232 233 if (convert == 0) 234 return write(fileno(file), buf, count); 235 236 p = buf; 237 ct = count; 238 while (ct--) { /* loop over the buffer */ 239 c = *p++; /* pick up a character */ 240 if (prevchar == '\r') { /* if prev char was cr */ 241 if (c == '\n') /* if have cr,lf then just */ 242 fseek(file, -1, 1); /* smash lf on top of the cr */ 243 else 244 if (c == '\0') /* if have cr,nul then */ 245 goto skipit; /* just skip over the putc */ 246 /* else just fall through and allow it */ 247 } 248 putc(c, file); 249skipit: 250 prevchar = c; 251 } 252 return count; 253} 254 255 256/* When an error has occurred, it is possible that the two sides 257 * are out of synch. Ie: that what I think is the other side's 258 * response to packet N is really their response to packet N-1. 259 * 260 * So, to try to prevent that, we flush all the input queued up 261 * for us on the network connection on our host. 262 * 263 * We return the number of packets we flushed (mostly for reporting 264 * when trace is active). 265 */ 266 267int 268synchnet(f) 269 int f; /* socket to flush */ 270{ 271 int i, j = 0; 272 char rbuf[PKTSIZE]; 273 struct sockaddr_storage from; 274 socklen_t fromlen; 275 276 while (1) { 277 (void) ioctl(f, FIONREAD, &i); 278 if (i) { 279 j++; 280 fromlen = sizeof from; 281 (void) recvfrom(f, rbuf, sizeof (rbuf), 0, 282 (struct sockaddr *)&from, &fromlen); 283 } else { 284 return(j); 285 } 286 } 287} 288