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 #ifndef lint 35 #if 0 36 static char sccsid[] = "@(#)tftpsubs.c 8.1 (Berkeley) 6/6/93"; 37 #endif 38 static const char rcsid[] = 39 "$FreeBSD: src/usr.bin/tftp/tftpsubs.c,v 1.3.2.1 2002/04/26 17:22:43 ume Exp $"; 40 #endif /* not lint */ 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 #define PKTSIZE SEGSIZE+4 /* should be moved to tftp.h */ 65 66 struct bf { 67 int counter; /* size of data in buffer, or flag */ 68 char buf[PKTSIZE]; /* room for data packet */ 69 } bfs[2]; 70 71 /* Values for bf.counter */ 72 #define BF_ALLOC -3 /* alloc'd but not yet filled */ 73 #define BF_FREE -2 /* free */ 74 /* [-1 .. SEGSIZE] = size of data in the data buffer */ 75 76 static int nextone; /* index of next buffer to use */ 77 static int current; /* index of buffer in use */ 78 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 static struct tftphdr *rw_init(); 84 85 struct tftphdr *w_init() { return rw_init(0); } /* write-behind */ 86 struct tftphdr *r_init() { return rw_init(1); } /* read-ahead */ 87 88 static struct tftphdr * 89 rw_init(x) /* init for either read-ahead or write-behind */ 90 int x; /* zero for write-behind, one for read-head */ 91 { 92 newline = 0; /* init crlf flag */ 93 prevchar = -1; 94 bfs[0].counter = BF_ALLOC; /* pass out the first buffer */ 95 current = 0; 96 bfs[1].counter = BF_FREE; 97 nextone = x; /* ahead or behind? */ 98 return (struct tftphdr *)bfs[0].buf; 99 } 100 101 102 /* Have emptied current buffer by sending to net and getting ack. 103 Free it and return next buffer filled with data. 104 */ 105 int 106 readit(file, dpp, convert) 107 FILE *file; /* file opened for read */ 108 struct tftphdr **dpp; 109 int convert; /* if true, convert to ascii */ 110 { 111 struct bf *b; 112 113 bfs[current].counter = BF_FREE; /* free old one */ 114 current = !current; /* "incr" current */ 115 116 b = &bfs[current]; /* look at new buffer */ 117 if (b->counter == BF_FREE) /* if it's empty */ 118 read_ahead(file, convert); /* fill it */ 119 /* assert(b->counter != BF_FREE);*//* check */ 120 *dpp = (struct tftphdr *)b->buf; /* set caller's ptr */ 121 return b->counter; 122 } 123 124 /* 125 * fill the input buffer, doing ascii conversions if requested 126 * conversions are lf -> cr,lf and cr -> cr, nul 127 */ 128 void 129 read_ahead(file, convert) 130 FILE *file; /* file opened for read */ 131 int convert; /* if true, convert to ascii */ 132 { 133 register int i; 134 register char *p; 135 register int c; 136 struct bf *b; 137 struct tftphdr *dp; 138 139 b = &bfs[nextone]; /* look at "next" buffer */ 140 if (b->counter != BF_FREE) /* nop if not free */ 141 return; 142 nextone = !nextone; /* "incr" next buffer ptr */ 143 144 dp = (struct tftphdr *)b->buf; 145 146 if (convert == 0) { 147 b->counter = read(fileno(file), dp->th_data, SEGSIZE); 148 return; 149 } 150 151 p = dp->th_data; 152 for (i = 0 ; i < SEGSIZE; i++) { 153 if (newline) { 154 if (prevchar == '\n') 155 c = '\n'; /* lf to cr,lf */ 156 else c = '\0'; /* cr to cr,nul */ 157 newline = 0; 158 } 159 else { 160 c = getc(file); 161 if (c == EOF) break; 162 if (c == '\n' || c == '\r') { 163 prevchar = c; 164 c = '\r'; 165 newline = 1; 166 } 167 } 168 *p++ = c; 169 } 170 b->counter = (int)(p - dp->th_data); 171 } 172 173 /* Update count associated with the buffer, get new buffer 174 from the queue. Calls write_behind only if next buffer not 175 available. 176 */ 177 int 178 writeit(file, dpp, ct, convert) 179 FILE *file; 180 struct tftphdr **dpp; 181 int ct, convert; 182 { 183 bfs[current].counter = ct; /* set size of data to write */ 184 current = !current; /* switch to other buffer */ 185 if (bfs[current].counter != BF_FREE) /* if not free */ 186 (void)write_behind(file, convert); /* flush it */ 187 bfs[current].counter = BF_ALLOC; /* mark as alloc'd */ 188 *dpp = (struct tftphdr *)bfs[current].buf; 189 return ct; /* this is a lie of course */ 190 } 191 192 /* 193 * Output a buffer to a file, converting from netascii if requested. 194 * CR,NUL -> CR and CR,LF => LF. 195 * Note spec is undefined if we get CR as last byte of file or a 196 * CR followed by anything else. In this case we leave it alone. 197 */ 198 int 199 write_behind(file, convert) 200 FILE *file; 201 int convert; 202 { 203 char *buf; 204 int count; 205 register int ct; 206 register char *p; 207 register int c; /* current character */ 208 struct bf *b; 209 struct tftphdr *dp; 210 211 b = &bfs[nextone]; 212 if (b->counter < -1) /* anything to flush? */ 213 return 0; /* just nop if nothing to do */ 214 215 count = b->counter; /* remember byte count */ 216 b->counter = BF_FREE; /* reset flag */ 217 dp = (struct tftphdr *)b->buf; 218 nextone = !nextone; /* incr for next time */ 219 buf = dp->th_data; 220 221 if (count <= 0) return -1; /* nak logic? */ 222 223 if (convert == 0) 224 return write(fileno(file), buf, count); 225 226 p = buf; 227 ct = count; 228 while (ct--) { /* loop over the buffer */ 229 c = *p++; /* pick up a character */ 230 if (prevchar == '\r') { /* if prev char was cr */ 231 if (c == '\n') /* if have cr,lf then just */ 232 fseek(file, -1, 1); /* smash lf on top of the cr */ 233 else 234 if (c == '\0') /* if have cr,nul then */ 235 goto skipit; /* just skip over the putc */ 236 /* else just fall through and allow it */ 237 } 238 putc(c, file); 239 skipit: 240 prevchar = c; 241 } 242 return count; 243 } 244 245 246 /* When an error has occurred, it is possible that the two sides 247 * are out of synch. Ie: that what I think is the other side's 248 * response to packet N is really their response to packet N-1. 249 * 250 * So, to try to prevent that, we flush all the input queued up 251 * for us on the network connection on our host. 252 * 253 * We return the number of packets we flushed (mostly for reporting 254 * when trace is active). 255 */ 256 257 int 258 synchnet(f) 259 int f; /* socket to flush */ 260 { 261 int i, j = 0; 262 char rbuf[PKTSIZE]; 263 struct sockaddr_storage from; 264 int fromlen; 265 266 while (1) { 267 (void) ioctl(f, FIONREAD, &i); 268 if (i) { 269 j++; 270 fromlen = sizeof from; 271 (void) recvfrom(f, rbuf, sizeof (rbuf), 0, 272 (struct sockaddr *)&from, &fromlen); 273 } else { 274 return(j); 275 } 276 } 277 } 278