1 /* $NetBSD: tftpsubs.c,v 1.3 1994/12/08 09:51:31 jtc 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. All advertising materials mentioning features or use of this software 16 * must display the following acknowledgement: 17 * This product includes software developed by the University of 18 * California, Berkeley and its contributors. 19 * 4. Neither the name of the University nor the names of its contributors 20 * may be used to endorse or promote products derived from this software 21 * without specific prior written permission. 22 * 23 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 24 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 25 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 26 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 27 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 28 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 29 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 30 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 31 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 32 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 33 * SUCH DAMAGE. 34 */ 35 36 #ifndef lint 37 #if 0 38 static char sccsid[] = "@(#)tftpsubs.c 8.1 (Berkeley) 6/6/93"; 39 #endif 40 static char rcsid[] = "$NetBSD: tftpsubs.c,v 1.3 1994/12/08 09:51:31 jtc Exp $"; 41 #endif /* not lint */ 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 #define PKTSIZE SEGSIZE+4 /* should be moved to tftp.h */ 66 67 struct bf { 68 int counter; /* size of data in buffer, or flag */ 69 char buf[PKTSIZE]; /* room for data packet */ 70 } bfs[2]; 71 72 /* Values for bf.counter */ 73 #define BF_ALLOC -3 /* alloc'd but not yet filled */ 74 #define BF_FREE -2 /* free */ 75 /* [-1 .. SEGSIZE] = size of data in the data buffer */ 76 77 static int nextone; /* index of next buffer to use */ 78 static int current; /* index of buffer in use */ 79 80 /* control flags for crlf conversions */ 81 int newline = 0; /* fillbuf: in middle of newline expansion */ 82 int prevchar = -1; /* putbuf: previous char (cr check) */ 83 84 static struct tftphdr *rw_init(); 85 86 struct tftphdr *w_init() { return rw_init(0); } /* write-behind */ 87 struct tftphdr *r_init() { return rw_init(1); } /* read-ahead */ 88 89 static struct tftphdr * 90 rw_init(x) /* init for either read-ahead or write-behind */ 91 int x; /* zero for write-behind, one for read-head */ 92 { 93 newline = 0; /* init crlf flag */ 94 prevchar = -1; 95 bfs[0].counter = BF_ALLOC; /* pass out the first buffer */ 96 current = 0; 97 bfs[1].counter = BF_FREE; 98 nextone = x; /* ahead or behind? */ 99 return (struct tftphdr *)bfs[0].buf; 100 } 101 102 103 /* Have emptied current buffer by sending to net and getting ack. 104 Free it and return next buffer filled with data. 105 */ 106 int 107 readit(file, dpp, convert) 108 FILE *file; /* file opened for read */ 109 struct tftphdr **dpp; 110 int convert; /* if true, convert to ascii */ 111 { 112 struct bf *b; 113 114 bfs[current].counter = BF_FREE; /* free old one */ 115 current = !current; /* "incr" current */ 116 117 b = &bfs[current]; /* look at new buffer */ 118 if (b->counter == BF_FREE) /* if it's empty */ 119 read_ahead(file, convert); /* fill it */ 120 /* assert(b->counter != BF_FREE);*//* check */ 121 *dpp = (struct tftphdr *)b->buf; /* set caller's ptr */ 122 return b->counter; 123 } 124 125 /* 126 * fill the input buffer, doing ascii conversions if requested 127 * conversions are lf -> cr,lf and cr -> cr, nul 128 */ 129 void 130 read_ahead(file, convert) 131 FILE *file; /* file opened for read */ 132 int convert; /* if true, convert to ascii */ 133 { 134 register int i; 135 register char *p; 136 register int c; 137 struct bf *b; 138 struct tftphdr *dp; 139 140 b = &bfs[nextone]; /* look at "next" buffer */ 141 if (b->counter != BF_FREE) /* nop if not free */ 142 return; 143 nextone = !nextone; /* "incr" next buffer ptr */ 144 145 dp = (struct tftphdr *)b->buf; 146 147 if (convert == 0) { 148 b->counter = read(fileno(file), dp->th_data, SEGSIZE); 149 return; 150 } 151 152 p = dp->th_data; 153 for (i = 0 ; i < SEGSIZE; i++) { 154 if (newline) { 155 if (prevchar == '\n') 156 c = '\n'; /* lf to cr,lf */ 157 else c = '\0'; /* cr to cr,nul */ 158 newline = 0; 159 } 160 else { 161 c = getc(file); 162 if (c == EOF) break; 163 if (c == '\n' || c == '\r') { 164 prevchar = c; 165 c = '\r'; 166 newline = 1; 167 } 168 } 169 *p++ = c; 170 } 171 b->counter = (int)(p - dp->th_data); 172 } 173 174 /* Update count associated with the buffer, get new buffer 175 from the queue. Calls write_behind only if next buffer not 176 available. 177 */ 178 int 179 writeit(file, dpp, ct, convert) 180 FILE *file; 181 struct tftphdr **dpp; 182 int ct, convert; 183 { 184 bfs[current].counter = ct; /* set size of data to write */ 185 current = !current; /* switch to other buffer */ 186 if (bfs[current].counter != BF_FREE) /* if not free */ 187 (void)write_behind(file, convert); /* flush it */ 188 bfs[current].counter = BF_ALLOC; /* mark as alloc'd */ 189 *dpp = (struct tftphdr *)bfs[current].buf; 190 return ct; /* this is a lie of course */ 191 } 192 193 /* 194 * Output a buffer to a file, converting from netascii if requested. 195 * CR,NUL -> CR and CR,LF => LF. 196 * Note spec is undefined if we get CR as last byte of file or a 197 * CR followed by anything else. In this case we leave it alone. 198 */ 199 int 200 write_behind(file, convert) 201 FILE *file; 202 int convert; 203 { 204 char *buf; 205 int count; 206 register int ct; 207 register char *p; 208 register int c; /* current character */ 209 struct bf *b; 210 struct tftphdr *dp; 211 212 b = &bfs[nextone]; 213 if (b->counter < -1) /* anything to flush? */ 214 return 0; /* just nop if nothing to do */ 215 216 count = b->counter; /* remember byte count */ 217 b->counter = BF_FREE; /* reset flag */ 218 dp = (struct tftphdr *)b->buf; 219 nextone = !nextone; /* incr for next time */ 220 buf = dp->th_data; 221 222 if (count <= 0) return -1; /* nak logic? */ 223 224 if (convert == 0) 225 return write(fileno(file), buf, count); 226 227 p = buf; 228 ct = count; 229 while (ct--) { /* loop over the buffer */ 230 c = *p++; /* pick up a character */ 231 if (prevchar == '\r') { /* if prev char was cr */ 232 if (c == '\n') /* if have cr,lf then just */ 233 fseek(file, -1, 1); /* smash lf on top of the cr */ 234 else 235 if (c == '\0') /* if have cr,nul then */ 236 goto skipit; /* just skip over the putc */ 237 /* else just fall through and allow it */ 238 } 239 putc(c, file); 240 skipit: 241 prevchar = c; 242 } 243 return count; 244 } 245 246 247 /* When an error has occurred, it is possible that the two sides 248 * are out of synch. Ie: that what I think is the other side's 249 * response to packet N is really their response to packet N-1. 250 * 251 * So, to try to prevent that, we flush all the input queued up 252 * for us on the network connection on our host. 253 * 254 * We return the number of packets we flushed (mostly for reporting 255 * when trace is active). 256 */ 257 258 int 259 synchnet(f) 260 int f; /* socket to flush */ 261 { 262 int i, j = 0; 263 char rbuf[PKTSIZE]; 264 struct sockaddr_in from; 265 int fromlen; 266 267 while (1) { 268 (void) ioctl(f, FIONREAD, &i); 269 if (i) { 270 j++; 271 fromlen = sizeof from; 272 (void) recvfrom(f, rbuf, sizeof (rbuf), 0, 273 (struct sockaddr *)&from, &fromlen); 274 } else { 275 return(j); 276 } 277 } 278 } 279