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 * @(#)tftpsubs.c 8.1 (Berkeley) 6/6/93 34 * $FreeBSD: src/usr.bin/tftp/tftpsubs.c,v 1.3.2.1 2002/04/26 17:22:43 ume Exp $ 35 * $DragonFly: src/usr.bin/tftp/tftpsubs.c,v 1.3 2003/10/04 20:36:52 hmp Exp $ 36 */ 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 55 #include <stdio.h> 56 #include <unistd.h> 57 58 #include "tftpsubs.h" 59 60 #define PKTSIZE SEGSIZE+4 /* should be moved to tftp.h */ 61 62 struct bf { 63 int counter; /* size of data in buffer, or flag */ 64 char buf[PKTSIZE]; /* room for data packet */ 65 } bfs[2]; 66 67 /* Values for bf.counter */ 68 #define BF_ALLOC -3 /* alloc'd but not yet filled */ 69 #define BF_FREE -2 /* free */ 70 /* [-1 .. SEGSIZE] = size of data in the data buffer */ 71 72 static int nextone; /* index of next buffer to use */ 73 static int current; /* index of buffer in use */ 74 75 /* control flags for crlf conversions */ 76 int newline = 0; /* fillbuf: in middle of newline expansion */ 77 int prevchar = -1; /* putbuf: previous char (cr check) */ 78 79 static struct tftphdr *rw_init(); 80 81 struct tftphdr *w_init() { return rw_init(0); } /* write-behind */ 82 struct tftphdr *r_init() { return rw_init(1); } /* read-ahead */ 83 84 static struct tftphdr * 85 rw_init(int x /* zero for write-behind, one for read-head */ 86 ) /* init for either read-ahead or write-behind */ 87 { 88 newline = 0; /* init crlf flag */ 89 prevchar = -1; 90 bfs[0].counter = BF_ALLOC; /* pass out the first buffer */ 91 current = 0; 92 bfs[1].counter = BF_FREE; 93 nextone = x; /* ahead or behind? */ 94 return (struct tftphdr *)bfs[0].buf; 95 } 96 97 98 /* Have emptied current buffer by sending to net and getting ack. 99 Free it and return next buffer filled with data. 100 */ 101 int 102 readit(FILE *file, /* file opened for read */ 103 struct tftphdr **dpp, 104 int convert /* if true, convert to ascii */ 105 ) 106 { 107 struct bf *b; 108 109 bfs[current].counter = BF_FREE; /* free old one */ 110 current = !current; /* "incr" current */ 111 112 b = &bfs[current]; /* look at new buffer */ 113 if (b->counter == BF_FREE) /* if it's empty */ 114 read_ahead(file, convert); /* fill it */ 115 /* assert(b->counter != BF_FREE);*//* check */ 116 *dpp = (struct tftphdr *)b->buf; /* set caller's ptr */ 117 return b->counter; 118 } 119 120 /* 121 * fill the input buffer, doing ascii conversions if requested 122 * conversions are lf -> cr,lf and cr -> cr, nul 123 */ 124 void 125 read_ahead(FILE *file, int convert) 126 { 127 register int i; 128 register char *p; 129 register int c; 130 struct bf *b; 131 struct tftphdr *dp; 132 133 b = &bfs[nextone]; /* look at "next" buffer */ 134 if (b->counter != BF_FREE) /* nop if not free */ 135 return; 136 nextone = !nextone; /* "incr" next buffer ptr */ 137 138 dp = (struct tftphdr *)b->buf; 139 140 if (convert == 0) { 141 b->counter = read(fileno(file), dp->th_data, SEGSIZE); 142 return; 143 } 144 145 p = dp->th_data; 146 for (i = 0 ; i < SEGSIZE; i++) { 147 if (newline) { 148 if (prevchar == '\n') 149 c = '\n'; /* lf to cr,lf */ 150 else c = '\0'; /* cr to cr,nul */ 151 newline = 0; 152 } 153 else { 154 c = getc(file); 155 if (c == EOF) break; 156 if (c == '\n' || c == '\r') { 157 prevchar = c; 158 c = '\r'; 159 newline = 1; 160 } 161 } 162 *p++ = c; 163 } 164 b->counter = (int)(p - dp->th_data); 165 } 166 167 /* Update count associated with the buffer, get new buffer 168 from the queue. Calls write_behind only if next buffer not 169 available. 170 */ 171 int 172 writeit(FILE *file, struct tftphdr **dpp, int ct, int convert) 173 { 174 bfs[current].counter = ct; /* set size of data to write */ 175 current = !current; /* switch to other buffer */ 176 if (bfs[current].counter != BF_FREE) /* if not free */ 177 (void)write_behind(file, convert); /* flush it */ 178 bfs[current].counter = BF_ALLOC; /* mark as alloc'd */ 179 *dpp = (struct tftphdr *)bfs[current].buf; 180 return ct; /* this is a lie of course */ 181 } 182 183 /* 184 * Output a buffer to a file, converting from netascii if requested. 185 * CR,NUL -> CR and CR,LF => LF. 186 * Note spec is undefined if we get CR as last byte of file or a 187 * CR followed by anything else. In this case we leave it alone. 188 */ 189 int 190 write_behind(FILE *file, 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(int f) 248 { 249 int i, j = 0; 250 char rbuf[PKTSIZE]; 251 struct sockaddr_storage 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