1 /* $OpenBSD: tftpsubs.c,v 1.13 2007/09/10 14:29:53 tobias Exp $ */ 2 /* $NetBSD: tftpsubs.c,v 1.3 1994/12/08 09:51:31 jtc Exp $ */ 3 4 /* 5 * Copyright (c) 1983, 1993 6 * The Regents of the University of California. All rights reserved. 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions 10 * are met: 11 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in the 15 * documentation and/or other materials provided with the distribution. 16 * 3. Neither the name of the University nor the names of its contributors 17 * may be used to endorse or promote products derived from this software 18 * without specific prior written permission. 19 * 20 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 23 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 30 * SUCH DAMAGE. 31 */ 32 33 #ifndef lint 34 #if 0 35 static char sccsid[] = "@(#)tftpsubs.c 8.1 (Berkeley) 6/6/93"; 36 #endif 37 static const char rcsid[] = 38 "$OpenBSD: tftpsubs.c,v 1.13 2007/09/10 14:29:53 tobias Exp $"; 39 #endif /* not lint */ 40 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 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 /* values for bf.counter */ 66 #define BF_ALLOC -3 /* alloc'd but not yet filled */ 67 #define BF_FREE -2 /* free */ 68 /* [-1 .. SEGSIZE] = size of data in the data buffer */ 69 70 static struct tftphdr *rw_init(int); 71 72 struct bf { 73 int counter; /* size of data in buffer, or flag */ 74 char buf[SEGSIZE_MAX + 4]; /* room for data packet */ 75 } bfs[2]; 76 77 static int nextone; /* index of next buffer to use */ 78 static int current; /* index of buffer in use */ 79 /* control flags for crlf conversions */ 80 int newline = 0; /* fillbuf: in middle of newline expansion */ 81 int prevchar = -1; /* putbuf: previous char (cr check) */ 82 83 struct tftphdr * 84 w_init(void) 85 { 86 return (rw_init(0)); /* write-behind */ 87 } 88 89 struct tftphdr * 90 r_init(void) 91 { 92 return (rw_init(1)); /* read-ahead */ 93 } 94 95 /* 96 * Init for either read-ahead or write-behind. 97 * Zero for write-behind, one for read-head. 98 */ 99 static struct tftphdr * 100 rw_init(int x) 101 { 102 newline = 0; /* init crlf flag */ 103 prevchar = -1; 104 bfs[0].counter = BF_ALLOC; /* pass out the first buffer */ 105 current = 0; 106 bfs[1].counter = BF_FREE; 107 nextone = x; /* ahead or behind? */ 108 109 return ((struct tftphdr *)bfs[0].buf); 110 } 111 112 /* 113 * Have emptied current buffer by sending to net and getting ack. 114 * Free it and return next buffer filled with data. 115 */ 116 int 117 readit(FILE *file, struct tftphdr **dpp, int convert, int segment_size) 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, convert, segment_size); /* fill it */ 127 /* assert(b->counter != BF_FREE); */ /* check */ 128 *dpp = (struct tftphdr *)b->buf; /* set caller's ptr */ 129 130 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 */ 137 void 138 read_ahead(FILE *file, int convert, int segment_size) 139 { 140 int i; 141 char *p; 142 int c; 143 struct bf *b; 144 struct tftphdr *dp; 145 146 b = &bfs[nextone]; /* look at "next" buffer */ 147 if (b->counter != BF_FREE) /* nop if not free */ 148 return; 149 nextone = !nextone; /* "incr" next buffer ptr */ 150 151 dp = (struct tftphdr *)b->buf; 152 153 if (convert == 0) { 154 b->counter = read(fileno(file), dp->th_data, segment_size); 155 return; 156 } 157 158 p = dp->th_data; 159 for (i = 0; i < segment_size; i++) { 160 if (newline) { 161 if (prevchar == '\n') 162 c = '\n'; /* lf to cr, lf */ 163 else 164 c = '\0'; /* cr to cr, nul */ 165 newline = 0; 166 } else { 167 c = getc(file); 168 if (c == EOF) 169 break; 170 if (c == '\n' || c == '\r') { 171 prevchar = c; 172 c = '\r'; 173 newline = 1; 174 } 175 } 176 *p++ = c; 177 } 178 b->counter = (int)(p - dp->th_data); 179 } 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 */ 186 int 187 writeit(FILE *file, struct tftphdr **dpp, int ct, int convert) 188 { 189 bfs[current].counter = ct; /* set size of data to write */ 190 current = !current; /* switch to other buffer */ 191 if (bfs[current].counter != BF_FREE) /* if not free */ 192 /* flush it */ 193 (void)write_behind(file, convert); 194 bfs[current].counter = BF_ALLOC; /* mark as alloc'd */ 195 *dpp = (struct tftphdr *)bfs[current].buf; 196 197 return (ct); /* this is a lie of course */ 198 } 199 200 /* 201 * Output a buffer to a file, converting from netascii if requested. 202 * CR, NUL -> CR and CR, LF -> LF. 203 * Note spec is undefined if we get CR as last byte of file or a 204 * CR followed by anything else. In this case we leave it alone. 205 */ 206 int 207 write_behind(FILE *file, int convert) 208 { 209 char *buf; 210 int count; 211 int ct; 212 char *p; 213 int c; /* current character */ 214 struct bf *b; 215 struct tftphdr *dp; 216 217 b = &bfs[nextone]; 218 if (b->counter < -1) /* anything to flush? */ 219 return (0); /* just nop if nothing to do */ 220 221 count = b->counter; /* remember byte count */ 222 b->counter = BF_FREE; /* reset flag */ 223 dp = (struct tftphdr *)b->buf; 224 nextone = !nextone; /* incr for next time */ 225 buf = dp->th_data; 226 227 if (count <= 0) /* nak logic? */ 228 return (-1); 229 230 if (convert == 0) 231 return (write(fileno(file), buf, count)); 232 233 p = buf; 234 ct = count; 235 while (ct--) { /* loop over the buffer */ 236 c = *p++; /* pick up a character */ 237 if (prevchar == '\r') { /* if prev char was cr */ 238 if (c == '\n') /* if have cr,lf then just */ 239 /* smash lf on top of the cr */ 240 fseek(file, -1, SEEK_CUR); 241 else if (c == '\0') /* if have cr,nul then */ 242 goto skipit; /* just skip over the putc */ 243 /* FALLTHROUGH */ 244 } 245 putc(c, file); 246 skipit: 247 prevchar = c; 248 } 249 250 return (count); 251 } 252 253 /* 254 * When an error has occurred, it is possible that the two sides 255 * are out of synch. Ie: that what I think is the other side's 256 * response to packet N is really their response to packet N-1. 257 * 258 * So, to try to prevent that, we flush all the input queued up 259 * for us on the network connection on our host. 260 * 261 * We return the number of packets we flushed (mostly for reporting 262 * when trace is active). 263 */ 264 int 265 synchnet(int f) 266 { 267 int i, j = 0; 268 char rbuf[SEGSIZE_MIN]; 269 struct sockaddr_in from; 270 socklen_t fromlen; 271 272 for (;;) { 273 (void)ioctl(f, FIONREAD, &i); 274 if (i) { 275 j++; 276 fromlen = sizeof(from); 277 (void)recvfrom(f, rbuf, sizeof(rbuf), 0, 278 (struct sockaddr *)&from, &fromlen); 279 } else 280 return (j); 281 } 282 } 283