1 /* $NetBSD: tftpsubs.c,v 1.6 1999/07/12 20:19:21 itojun 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 #include <sys/cdefs.h> 37 #ifndef lint 38 #if 0 39 static char sccsid[] = "@(#)tftpsubs.c 8.1 (Berkeley) 6/6/93"; 40 #else 41 __RCSID("$NetBSD: tftpsubs.c,v 1.6 1999/07/12 20:19:21 itojun Exp $"); 42 #endif 43 #endif /* not lint */ 44 45 /* Simple minded read-ahead/write-behind subroutines for tftp user and 46 server. Written originally with multiple buffers in mind, but current 47 implementation has two buffer logic wired in. 48 49 Todo: add some sort of final error check so when the write-buffer 50 is finally flushed, the caller can detect if the disk filled up 51 (or had an i/o error) and return a nak to the other side. 52 53 Jim Guyton 10/85 54 */ 55 56 #include <sys/types.h> 57 #include <sys/socket.h> 58 #include <sys/ioctl.h> 59 #include <netinet/in.h> 60 #include <arpa/tftp.h> 61 62 #include <stdio.h> 63 #include <unistd.h> 64 65 #include "tftpsubs.h" 66 67 #define PKTSIZE SEGSIZE+4 /* should be moved to tftp.h */ 68 69 struct bf { 70 int counter; /* size of data in buffer, or flag */ 71 char buf[PKTSIZE]; /* room for data packet */ 72 } bfs[2]; 73 74 /* Values for bf.counter */ 75 #define BF_ALLOC -3 /* alloc'd but not yet filled */ 76 #define BF_FREE -2 /* free */ 77 /* [-1 .. SEGSIZE] = size of data in the data buffer */ 78 79 static int nextone; /* index of next buffer to use */ 80 static int current; /* index of buffer in use */ 81 82 /* control flags for crlf conversions */ 83 int newline = 0; /* fillbuf: in middle of newline expansion */ 84 int prevchar = -1; /* putbuf: previous char (cr check) */ 85 86 static struct tftphdr *rw_init __P((int)); 87 88 struct tftphdr *w_init() { return rw_init(0); } /* write-behind */ 89 struct tftphdr *r_init() { return rw_init(1); } /* read-ahead */ 90 91 static struct tftphdr * 92 rw_init(x) /* init for either read-ahead or write-behind */ 93 int x; /* zero for write-behind, one for read-head */ 94 { 95 newline = 0; /* init crlf flag */ 96 prevchar = -1; 97 bfs[0].counter = BF_ALLOC; /* pass out the first buffer */ 98 current = 0; 99 bfs[1].counter = BF_FREE; 100 nextone = x; /* ahead or behind? */ 101 return (struct tftphdr *)bfs[0].buf; 102 } 103 104 /* Have emptied current buffer by sending to net and getting ack. 105 Free it and return next buffer filled with data. 106 */ 107 int 108 readit(file, dpp, convert) 109 FILE *file; /* file opened for read */ 110 struct tftphdr **dpp; 111 int convert; /* if true, convert to ascii */ 112 { 113 struct bf *b; 114 115 bfs[current].counter = BF_FREE; /* free old one */ 116 current = !current; /* "incr" current */ 117 118 b = &bfs[current]; /* look at new buffer */ 119 if (b->counter == BF_FREE) /* if it's empty */ 120 read_ahead(file, convert); /* fill it */ 121 /* assert(b->counter != BF_FREE);*//* check */ 122 *dpp = (struct tftphdr *)b->buf; /* set caller's ptr */ 123 return b->counter; 124 } 125 126 /* 127 * fill the input buffer, doing ascii conversions if requested 128 * conversions are lf -> cr,lf and cr -> cr, nul 129 */ 130 void 131 read_ahead(file, convert) 132 FILE *file; /* file opened for read */ 133 int convert; /* if true, convert to ascii */ 134 { 135 int i; 136 char *p; 137 int c; 138 struct bf *b; 139 struct tftphdr *dp; 140 141 b = &bfs[nextone]; /* look at "next" buffer */ 142 if (b->counter != BF_FREE) /* nop if not free */ 143 return; 144 nextone = !nextone; /* "incr" next buffer ptr */ 145 146 dp = (struct tftphdr *)b->buf; 147 148 if (convert == 0) { 149 b->counter = read(fileno(file), dp->th_data, SEGSIZE); 150 return; 151 } 152 153 p = dp->th_data; 154 for (i = 0 ; i < SEGSIZE; i++) { 155 if (newline) { 156 if (prevchar == '\n') 157 c = '\n'; /* lf to cr,lf */ 158 else c = '\0'; /* cr to cr,nul */ 159 newline = 0; 160 } 161 else { 162 c = getc(file); 163 if (c == EOF) break; 164 if (c == '\n' || c == '\r') { 165 prevchar = c; 166 c = '\r'; 167 newline = 1; 168 } 169 } 170 *p++ = c; 171 } 172 b->counter = (int)(p - dp->th_data); 173 } 174 175 /* Update count associated with the buffer, get new buffer 176 from the queue. Calls write_behind only if next buffer not 177 available. 178 */ 179 int 180 writeit(file, dpp, ct, convert) 181 FILE *file; 182 struct tftphdr **dpp; 183 int ct, convert; 184 { 185 bfs[current].counter = ct; /* set size of data to write */ 186 current = !current; /* switch to other buffer */ 187 if (bfs[current].counter != BF_FREE) /* if not free */ 188 (void)write_behind(file, convert); /* flush it */ 189 bfs[current].counter = BF_ALLOC; /* mark as alloc'd */ 190 *dpp = (struct tftphdr *)bfs[current].buf; 191 return ct; /* this is a lie of course */ 192 } 193 194 /* 195 * Output a buffer to a file, converting from netascii if requested. 196 * CR,NUL -> CR and CR,LF => LF. 197 * Note spec is undefined if we get CR as last byte of file or a 198 * CR followed by anything else. In this case we leave it alone. 199 */ 200 int 201 write_behind(file, convert) 202 FILE *file; 203 int convert; 204 { 205 char *buf; 206 int count; 207 int ct; 208 char *p; 209 int c; /* current character */ 210 struct bf *b; 211 struct tftphdr *dp; 212 213 b = &bfs[nextone]; 214 if (b->counter < -1) /* anything to flush? */ 215 return 0; /* just nop if nothing to do */ 216 217 count = b->counter; /* remember byte count */ 218 b->counter = BF_FREE; /* reset flag */ 219 dp = (struct tftphdr *)b->buf; 220 nextone = !nextone; /* incr for next time */ 221 buf = dp->th_data; 222 223 if (count <= 0) return -1; /* nak logic? */ 224 225 if (convert == 0) 226 return write(fileno(file), buf, count); 227 228 p = buf; 229 ct = count; 230 while (ct--) { /* loop over the buffer */ 231 c = *p++; /* pick up a character */ 232 if (prevchar == '\r') { /* if prev char was cr */ 233 if (c == '\n') /* if have cr,lf then just */ 234 fseek(file, -1, 1); /* smash lf on top of the cr */ 235 else 236 if (c == '\0') /* if have cr,nul then */ 237 goto skipit; /* just skip over the putc */ 238 /* else just fall through and allow it */ 239 } 240 putc(c, file); 241 skipit: 242 prevchar = c; 243 } 244 return count; 245 } 246 247 248 /* When an error has occurred, it is possible that the two sides 249 * are out of synch. Ie: that what I think is the other side's 250 * response to packet N is really their response to packet N-1. 251 * 252 * So, to try to prevent that, we flush all the input queued up 253 * for us on the network connection on our host. 254 * 255 * We return the number of packets we flushed (mostly for reporting 256 * when trace is active). 257 */ 258 259 int 260 synchnet(f) 261 int f; /* socket to flush */ 262 { 263 int i, j = 0; 264 char rbuf[PKTSIZE]; 265 struct sockaddr_storage from; 266 int fromlen; 267 268 while (1) { 269 (void) ioctl(f, FIONREAD, &i); 270 if (i) { 271 j++; 272 fromlen = sizeof from; 273 (void) recvfrom(f, rbuf, sizeof (rbuf), 0, 274 (struct sockaddr *)&from, &fromlen); 275 } else { 276 return(j); 277 } 278 } 279 } 280