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[] = "from: @(#)tftpsubs.c 5.6 (Berkeley) 2/28/91";*/ 36 static char rcsid[] = "$Id: tftpsubs.c,v 1.2 1993/08/01 18:07:04 mycroft Exp $"; 37 #endif /* not lint */ 38 39 /* Simple minded read-ahead/write-behind subroutines for tftp user and 40 server. Written originally with multiple buffers in mind, but current 41 implementation has two buffer logic wired in. 42 43 Todo: add some sort of final error check so when the write-buffer 44 is finally flushed, the caller can detect if the disk filled up 45 (or had an i/o error) and return a nak to the other side. 46 47 Jim Guyton 10/85 48 */ 49 50 #include <sys/types.h> 51 #include <sys/socket.h> 52 #include <sys/ioctl.h> 53 #include <netinet/in.h> 54 #include <arpa/tftp.h> 55 #include <stdio.h> 56 57 #define PKTSIZE SEGSIZE+4 /* should be moved to tftp.h */ 58 59 struct bf { 60 int counter; /* size of data in buffer, or flag */ 61 char buf[PKTSIZE]; /* room for data packet */ 62 } bfs[2]; 63 64 /* Values for bf.counter */ 65 #define BF_ALLOC -3 /* alloc'd but not yet filled */ 66 #define BF_FREE -2 /* free */ 67 /* [-1 .. SEGSIZE] = size of data in the data buffer */ 68 69 static int nextone; /* index of next buffer to use */ 70 static int current; /* index of buffer in use */ 71 72 /* control flags for crlf conversions */ 73 int newline = 0; /* fillbuf: in middle of newline expansion */ 74 int prevchar = -1; /* putbuf: previous char (cr check) */ 75 76 struct tftphdr *rw_init(); 77 78 struct tftphdr *w_init() { return rw_init(0); } /* write-behind */ 79 struct tftphdr *r_init() { return rw_init(1); } /* read-ahead */ 80 81 struct tftphdr * 82 rw_init(x) /* init for either read-ahead or write-behind */ 83 int x; /* zero for write-behind, one for read-head */ 84 { 85 newline = 0; /* init crlf flag */ 86 prevchar = -1; 87 bfs[0].counter = BF_ALLOC; /* pass out the first buffer */ 88 current = 0; 89 bfs[1].counter = BF_FREE; 90 nextone = x; /* ahead or behind? */ 91 return (struct tftphdr *)bfs[0].buf; 92 } 93 94 95 /* Have emptied current buffer by sending to net and getting ack. 96 Free it and return next buffer filled with data. 97 */ 98 readit(file, dpp, convert) 99 FILE *file; /* file opened for read */ 100 struct tftphdr **dpp; 101 int convert; /* if true, convert to ascii */ 102 { 103 struct bf *b; 104 105 bfs[current].counter = BF_FREE; /* free old one */ 106 current = !current; /* "incr" current */ 107 108 b = &bfs[current]; /* look at new buffer */ 109 if (b->counter == BF_FREE) /* if it's empty */ 110 read_ahead(file, convert); /* fill it */ 111 /* assert(b->counter != BF_FREE); /* check */ 112 *dpp = (struct tftphdr *)b->buf; /* set caller's ptr */ 113 return b->counter; 114 } 115 116 /* 117 * fill the input buffer, doing ascii conversions if requested 118 * conversions are lf -> cr,lf and cr -> cr, nul 119 */ 120 read_ahead(file, convert) 121 FILE *file; /* file opened for read */ 122 int convert; /* if true, convert to ascii */ 123 { 124 register int i; 125 register char *p; 126 register int c; 127 struct bf *b; 128 struct tftphdr *dp; 129 130 b = &bfs[nextone]; /* look at "next" buffer */ 131 if (b->counter != BF_FREE) /* nop if not free */ 132 return; 133 nextone = !nextone; /* "incr" next buffer ptr */ 134 135 dp = (struct tftphdr *)b->buf; 136 137 if (convert == 0) { 138 b->counter = read(fileno(file), dp->th_data, SEGSIZE); 139 return; 140 } 141 142 p = dp->th_data; 143 for (i = 0 ; i < SEGSIZE; i++) { 144 if (newline) { 145 if (prevchar == '\n') 146 c = '\n'; /* lf to cr,lf */ 147 else c = '\0'; /* cr to cr,nul */ 148 newline = 0; 149 } 150 else { 151 c = getc(file); 152 if (c == EOF) break; 153 if (c == '\n' || c == '\r') { 154 prevchar = c; 155 c = '\r'; 156 newline = 1; 157 } 158 } 159 *p++ = c; 160 } 161 b->counter = (int)(p - dp->th_data); 162 } 163 164 /* Update count associated with the buffer, get new buffer 165 from the queue. Calls write_behind only if next buffer not 166 available. 167 */ 168 writeit(file, dpp, ct, convert) 169 FILE *file; 170 struct tftphdr **dpp; 171 int convert; 172 { 173 bfs[current].counter = ct; /* set size of data to write */ 174 current = !current; /* switch to other buffer */ 175 if (bfs[current].counter != BF_FREE) /* if not free */ 176 write_behind(file, convert); /* flush it */ 177 bfs[current].counter = BF_ALLOC; /* mark as alloc'd */ 178 *dpp = (struct tftphdr *)bfs[current].buf; 179 return ct; /* this is a lie of course */ 180 } 181 182 /* 183 * Output a buffer to a file, converting from netascii if requested. 184 * CR,NUL -> CR and CR,LF => LF. 185 * Note spec is undefined if we get CR as last byte of file or a 186 * CR followed by anything else. In this case we leave it alone. 187 */ 188 write_behind(file, convert) 189 FILE *file; 190 int convert; 191 { 192 char *buf; 193 int count; 194 register int ct; 195 register char *p; 196 register int c; /* current character */ 197 struct bf *b; 198 struct tftphdr *dp; 199 200 b = &bfs[nextone]; 201 if (b->counter < -1) /* anything to flush? */ 202 return 0; /* just nop if nothing to do */ 203 204 count = b->counter; /* remember byte count */ 205 b->counter = BF_FREE; /* reset flag */ 206 dp = (struct tftphdr *)b->buf; 207 nextone = !nextone; /* incr for next time */ 208 buf = dp->th_data; 209 210 if (count <= 0) return -1; /* nak logic? */ 211 212 if (convert == 0) 213 return write(fileno(file), buf, count); 214 215 p = buf; 216 ct = count; 217 while (ct--) { /* loop over the buffer */ 218 c = *p++; /* pick up a character */ 219 if (prevchar == '\r') { /* if prev char was cr */ 220 if (c == '\n') /* if have cr,lf then just */ 221 fseek(file, -1, 1); /* smash lf on top of the cr */ 222 else 223 if (c == '\0') /* if have cr,nul then */ 224 goto skipit; /* just skip over the putc */ 225 /* else just fall through and allow it */ 226 } 227 putc(c, file); 228 skipit: 229 prevchar = c; 230 } 231 return count; 232 } 233 234 235 /* When an error has occurred, it is possible that the two sides 236 * are out of synch. Ie: that what I think is the other side's 237 * response to packet N is really their response to packet N-1. 238 * 239 * So, to try to prevent that, we flush all the input queued up 240 * for us on the network connection on our host. 241 * 242 * We return the number of packets we flushed (mostly for reporting 243 * when trace is active). 244 */ 245 246 int 247 synchnet(f) 248 int f; /* socket to flush */ 249 { 250 int i, j = 0; 251 char rbuf[PKTSIZE]; 252 struct sockaddr_in from; 253 int fromlen; 254 255 while (1) { 256 (void) ioctl(f, FIONREAD, &i); 257 if (i) { 258 j++; 259 fromlen = sizeof from; 260 (void) recvfrom(f, rbuf, sizeof (rbuf), 0, 261 (struct sockaddr *)&from, &fromlen); 262 } else { 263 return(j); 264 } 265 } 266 } 267