1 /* 2 * Copyright (c) 1983 Regents of the University of California. 3 * 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 static char sccsid[] = "@(#)tftpsubs.c 5.6 (Berkeley) 2/28/91"; 36 #endif /* not lint */ 37 38 /* Simple minded read-ahead/write-behind subroutines for tftp user and 39 server. Written originally with multiple buffers in mind, but current 40 implementation has two buffer logic wired in. 41 42 Todo: add some sort of final error check so when the write-buffer 43 is finally flushed, the caller can detect if the disk filled up 44 (or had an i/o error) and return a nak to the other side. 45 46 Jim Guyton 10/85 47 */ 48 49 #include <sys/types.h> 50 #include <sys/socket.h> 51 #include <sys/ioctl.h> 52 #include <netinet/in.h> 53 #include <arpa/tftp.h> 54 #include <stdio.h> 55 56 #define PKTSIZE SEGSIZE+4 /* should be moved to tftp.h */ 57 58 struct bf { 59 int counter; /* size of data in buffer, or flag */ 60 char buf[PKTSIZE]; /* room for data packet */ 61 } bfs[2]; 62 63 /* Values for bf.counter */ 64 #define BF_ALLOC -3 /* alloc'd but not yet filled */ 65 #define BF_FREE -2 /* free */ 66 /* [-1 .. SEGSIZE] = size of data in the data buffer */ 67 68 static int nextone; /* index of next buffer to use */ 69 static int current; /* index of buffer in use */ 70 71 /* control flags for crlf conversions */ 72 int newline = 0; /* fillbuf: in middle of newline expansion */ 73 int prevchar = -1; /* putbuf: previous char (cr check) */ 74 75 struct tftphdr *rw_init(); 76 77 struct tftphdr *w_init() { return rw_init(0); } /* write-behind */ 78 struct tftphdr *r_init() { return rw_init(1); } /* read-ahead */ 79 80 struct tftphdr * 81 rw_init(x) /* init for either read-ahead or write-behind */ 82 int x; /* zero for write-behind, one for read-head */ 83 { 84 newline = 0; /* init crlf flag */ 85 prevchar = -1; 86 bfs[0].counter = BF_ALLOC; /* pass out the first buffer */ 87 current = 0; 88 bfs[1].counter = BF_FREE; 89 nextone = x; /* ahead or behind? */ 90 return (struct tftphdr *)bfs[0].buf; 91 } 92 93 94 /* Have emptied current buffer by sending to net and getting ack. 95 Free it and return next buffer filled with data. 96 */ 97 readit(file, dpp, convert) 98 FILE *file; /* file opened for read */ 99 struct tftphdr **dpp; 100 int convert; /* if true, convert to ascii */ 101 { 102 struct bf *b; 103 104 bfs[current].counter = BF_FREE; /* free old one */ 105 current = !current; /* "incr" current */ 106 107 b = &bfs[current]; /* look at new buffer */ 108 if (b->counter == BF_FREE) /* if it's empty */ 109 read_ahead(file, convert); /* fill it */ 110 /* assert(b->counter != BF_FREE); /* check */ 111 *dpp = (struct tftphdr *)b->buf; /* set caller's ptr */ 112 return b->counter; 113 } 114 115 /* 116 * fill the input buffer, doing ascii conversions if requested 117 * conversions are lf -> cr,lf and cr -> cr, nul 118 */ 119 read_ahead(file, convert) 120 FILE *file; /* file opened for read */ 121 int convert; /* if true, convert to ascii */ 122 { 123 register int i; 124 register char *p; 125 register int c; 126 struct bf *b; 127 struct tftphdr *dp; 128 129 b = &bfs[nextone]; /* look at "next" buffer */ 130 if (b->counter != BF_FREE) /* nop if not free */ 131 return; 132 nextone = !nextone; /* "incr" next buffer ptr */ 133 134 dp = (struct tftphdr *)b->buf; 135 136 if (convert == 0) { 137 b->counter = read(fileno(file), dp->th_data, SEGSIZE); 138 return; 139 } 140 141 p = dp->th_data; 142 for (i = 0 ; i < SEGSIZE; i++) { 143 if (newline) { 144 if (prevchar == '\n') 145 c = '\n'; /* lf to cr,lf */ 146 else c = '\0'; /* cr to cr,nul */ 147 newline = 0; 148 } 149 else { 150 c = getc(file); 151 if (c == EOF) break; 152 if (c == '\n' || c == '\r') { 153 prevchar = c; 154 c = '\r'; 155 newline = 1; 156 } 157 } 158 *p++ = c; 159 } 160 b->counter = (int)(p - dp->th_data); 161 } 162 163 /* Update count associated with the buffer, get new buffer 164 from the queue. Calls write_behind only if next buffer not 165 available. 166 */ 167 writeit(file, dpp, ct, convert) 168 FILE *file; 169 struct tftphdr **dpp; 170 int convert; 171 { 172 bfs[current].counter = ct; /* set size of data to write */ 173 current = !current; /* switch to other buffer */ 174 if (bfs[current].counter != BF_FREE) /* if not free */ 175 write_behind(file, convert); /* flush it */ 176 bfs[current].counter = BF_ALLOC; /* mark as alloc'd */ 177 *dpp = (struct tftphdr *)bfs[current].buf; 178 return ct; /* this is a lie of course */ 179 } 180 181 /* 182 * Output a buffer to a file, converting from netascii if requested. 183 * CR,NUL -> CR and CR,LF => LF. 184 * Note spec is undefined if we get CR as last byte of file or a 185 * CR followed by anything else. In this case we leave it alone. 186 */ 187 write_behind(file, convert) 188 FILE *file; 189 int convert; 190 { 191 char *buf; 192 int count; 193 register int ct; 194 register char *p; 195 register int c; /* current character */ 196 struct bf *b; 197 struct tftphdr *dp; 198 199 b = &bfs[nextone]; 200 if (b->counter < -1) /* anything to flush? */ 201 return 0; /* just nop if nothing to do */ 202 203 count = b->counter; /* remember byte count */ 204 b->counter = BF_FREE; /* reset flag */ 205 dp = (struct tftphdr *)b->buf; 206 nextone = !nextone; /* incr for next time */ 207 buf = dp->th_data; 208 209 if (count <= 0) return -1; /* nak logic? */ 210 211 if (convert == 0) 212 return write(fileno(file), buf, count); 213 214 p = buf; 215 ct = count; 216 while (ct--) { /* loop over the buffer */ 217 c = *p++; /* pick up a character */ 218 if (prevchar == '\r') { /* if prev char was cr */ 219 if (c == '\n') /* if have cr,lf then just */ 220 fseek(file, -1, 1); /* smash lf on top of the cr */ 221 else 222 if (c == '\0') /* if have cr,nul then */ 223 goto skipit; /* just skip over the putc */ 224 /* else just fall through and allow it */ 225 } 226 putc(c, file); 227 skipit: 228 prevchar = c; 229 } 230 return count; 231 } 232 233 234 /* When an error has occurred, it is possible that the two sides 235 * are out of synch. Ie: that what I think is the other side's 236 * response to packet N is really their response to packet N-1. 237 * 238 * So, to try to prevent that, we flush all the input queued up 239 * for us on the network connection on our host. 240 * 241 * We return the number of packets we flushed (mostly for reporting 242 * when trace is active). 243 */ 244 245 int 246 synchnet(f) 247 int f; /* socket to flush */ 248 { 249 int i, j = 0; 250 char rbuf[PKTSIZE]; 251 struct sockaddr_in from; 252 int fromlen; 253 254 while (1) { 255 (void) ioctl(f, FIONREAD, &i); 256 if (i) { 257 j++; 258 fromlen = sizeof from; 259 (void) recvfrom(f, rbuf, sizeof (rbuf), 0, 260 (struct sockaddr *)&from, &fromlen); 261 } else { 262 return(j); 263 } 264 } 265 } 266