1 /* $NetBSD: tftpsubs.c,v 1.11 2009/01/18 07:11:45 lukem Exp $ */ 2 3 /* 4 * Copyright (c) 1983, 1993 5 * The Regents of the University of California. All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 3. Neither the name of the University nor the names of its contributors 16 * may be used to endorse or promote products derived from this software 17 * without specific prior written permission. 18 * 19 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 22 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 29 * SUCH DAMAGE. 30 */ 31 32 #include <sys/cdefs.h> 33 #ifndef lint 34 #if 0 35 static char sccsid[] = "@(#)tftpsubs.c 8.1 (Berkeley) 6/6/93"; 36 #else 37 __RCSID("$NetBSD: tftpsubs.c,v 1.11 2009/01/18 07:11:45 lukem Exp $"); 38 #endif 39 #endif /* not lint */ 40 41 /* Simple minded read-ahead/write-behind subroutines for tftp user and 42 server. Written originally with multiple buffers in mind, but current 43 implementation has two buffer logic wired in. 44 45 Todo: add some sort of final error check so when the write-buffer 46 is finally flushed, the caller can detect if the disk filled up 47 (or had an i/o error) and return a nak to the other side. 48 49 Jim Guyton 10/85 50 */ 51 52 #include <sys/types.h> 53 #include <sys/socket.h> 54 #include <sys/ioctl.h> 55 #include <netinet/in.h> 56 #include <arpa/tftp.h> 57 58 #include <stdio.h> 59 #include <unistd.h> 60 61 #include "tftpsubs.h" 62 63 struct bf { 64 int counter; /* size of data in buffer, or flag */ 65 char buf[MAXPKTSIZE]; /* room for data packet */ 66 } bfs[2]; 67 68 /* Values for bf.counter */ 69 #define BF_ALLOC -3 /* alloc'd but not yet filled */ 70 #define BF_FREE -2 /* free */ 71 /* [-1 .. SEGSIZE] = size of data in the data buffer */ 72 73 static int nextone; /* index of next buffer to use */ 74 static int current; /* index of buffer in use */ 75 76 /* control flags for crlf conversions */ 77 int newline = 0; /* fillbuf: in middle of newline expansion */ 78 int prevchar = -1; /* putbuf: previous char (cr check) */ 79 80 static struct tftphdr *rw_init __P((int)); 81 82 struct tftphdr * 83 w_init() /* write-behind */ 84 { 85 return rw_init(0); 86 } 87 88 struct tftphdr * 89 r_init() /* read-ahead */ 90 { 91 return rw_init(1); 92 } 93 94 static struct tftphdr * 95 rw_init(x) /* init for either read-ahead or write-behind */ 96 int x; /* zero for write-behind, one for read-head */ 97 { 98 newline = 0; /* init crlf flag */ 99 prevchar = -1; 100 bfs[0].counter = BF_ALLOC; /* pass out the first buffer */ 101 current = 0; 102 bfs[1].counter = BF_FREE; 103 nextone = x; /* ahead or behind? */ 104 return (struct tftphdr *)(void *)bfs[0].buf; 105 } 106 107 /* Have emptied current buffer by sending to net and getting ack. 108 Free it and return next buffer filled with data. 109 */ 110 int 111 readit(file, dpp, amt, convert) 112 FILE *file; /* file opened for read */ 113 struct tftphdr **dpp; 114 size_t amt; 115 int convert; /* if true, convert to ascii */ 116 { 117 struct bf *b; 118 119 bfs[current].counter = BF_FREE; /* free old one */ 120 current = !current; /* "incr" current */ 121 122 b = &bfs[current]; /* look at new buffer */ 123 if (b->counter == BF_FREE) /* if it's empty */ 124 read_ahead(file, amt, convert); /* fill it */ 125 /* assert(b->counter != BF_FREE);*//* check */ 126 *dpp = (struct tftphdr *)(void *)b->buf; /* set caller's ptr */ 127 return b->counter; 128 } 129 130 /* 131 * fill the input buffer, doing ascii conversions if requested 132 * conversions are lf -> cr,lf and cr -> cr, nul 133 */ 134 void 135 read_ahead(file, amt, convert) 136 FILE *file; /* file opened for read */ 137 size_t amt; /* number of bytes to read */ 138 int convert; /* if true, convert to ascii */ 139 { 140 size_t 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 *)(void *)b->buf; 152 153 if (convert == 0) { 154 b->counter = read(fileno(file), dp->th_data, amt); 155 return; 156 } 157 158 p = dp->th_data; 159 for (i = 0 ; i < amt; i++) { 160 if (newline) { 161 if (prevchar == '\n') 162 c = '\n'; /* lf to cr,lf */ 163 else c = '\0'; /* cr to cr,nul */ 164 newline = 0; 165 } 166 else { 167 c = getc(file); 168 if (c == EOF) break; 169 if (c == '\n' || c == '\r') { 170 prevchar = c; 171 c = '\r'; 172 newline = 1; 173 } 174 } 175 *p++ = c; 176 } 177 b->counter = (int)(p - dp->th_data); 178 } 179 180 /* Update count associated with the buffer, get new buffer 181 from the queue. Calls write_behind only if next buffer not 182 available. 183 */ 184 int 185 writeit(file, dpp, ct, convert) 186 FILE *file; 187 struct tftphdr **dpp; 188 int ct, convert; 189 { 190 bfs[current].counter = ct; /* set size of data to write */ 191 current = !current; /* switch to other buffer */ 192 if (bfs[current].counter != BF_FREE) /* if not free */ 193 if (write_behind(file, convert) == -1) /* flush it */ 194 return -1; 195 bfs[current].counter = BF_ALLOC; /* mark as alloc'd */ 196 *dpp = (struct tftphdr *)(void *)bfs[current].buf; 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, convert) 208 FILE *file; 209 int convert; 210 { 211 char *buf; 212 int count; 213 int ct; 214 char *p; 215 int c; /* current character */ 216 struct bf *b; 217 struct tftphdr *dp; 218 219 b = &bfs[nextone]; 220 if (b->counter < -1) /* anything to flush? */ 221 return 0; /* just nop if nothing to do */ 222 223 count = b->counter; /* remember byte count */ 224 b->counter = BF_FREE; /* reset flag */ 225 dp = (struct tftphdr *)(void *)b->buf; 226 nextone = !nextone; /* incr for next time */ 227 buf = dp->th_data; 228 229 if (count <= 0) return -1; /* nak logic? */ 230 231 if (convert == 0) 232 return write(fileno(file), buf, (size_t)count); 233 234 p = buf; 235 ct = count; 236 while (ct--) { /* loop over the buffer */ 237 c = *p++; /* pick up a character */ 238 if (prevchar == '\r') { /* if prev char was cr */ 239 if (c == '\n') /* if have cr,lf then just */ 240 (void)fseeko(file, (off_t)-1, 1); /* smash lf on top of the cr */ 241 else 242 if (c == '\0') /* if have cr,nul then */ 243 goto skipit; /* just skip over the putc */ 244 /* else just fall through and allow it */ 245 } 246 if (putc(c, file) == EOF) 247 return -1; 248 skipit: 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 */ 265 266 int 267 /*ARGSUSED*/ 268 synchnet(f, bsize) 269 int f; /* socket to flush */ 270 size_t bsize; /* size of buffer to sync */ 271 { 272 int i, j = 0; 273 char rbuf[PKTSIZE]; 274 struct sockaddr_storage from; 275 socklen_t fromlen; 276 277 for (;;) { 278 (void) ioctl(f, FIONREAD, &i); 279 if (i) { 280 j++; 281 fromlen = sizeof from; 282 (void) recvfrom(f, rbuf, sizeof (rbuf), 0, 283 (struct sockaddr *)(void *)&from, &fromlen); 284 } else { 285 return(j); 286 } 287 } 288 } 289