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 * 4. Neither the name of the University nor the names of its contributors 14 * may be used to endorse or promote products derived from this software 15 * without specific prior written permission. 16 * 17 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 20 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 27 * SUCH DAMAGE. 28 * 29 * @(#)tftpsubs.c 8.1 (Berkeley) 6/6/93 30 * $FreeBSD: src/usr.bin/tftp/tftpsubs.c,v 1.3.2.1 2002/04/26 17:22:43 ume Exp $ 31 * $DragonFly: src/usr.bin/tftp/tftpsubs.c,v 1.4 2008/10/16 01:52:33 swildner Exp $ 32 */ 33 34 /* Simple minded read-ahead/write-behind subroutines for tftp user and 35 server. Written originally with multiple buffers in mind, but current 36 implementation has two buffer logic wired in. 37 38 Todo: add some sort of final error check so when the write-buffer 39 is finally flushed, the caller can detect if the disk filled up 40 (or had an i/o error) and return a nak to the other side. 41 42 Jim Guyton 10/85 43 */ 44 45 #include <sys/types.h> 46 #include <sys/socket.h> 47 #include <sys/ioctl.h> 48 #include <netinet/in.h> 49 #include <arpa/tftp.h> 50 51 #include <stdio.h> 52 #include <unistd.h> 53 54 #include "tftpsubs.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 static struct tftphdr *rw_init(int); 76 77 struct tftphdr *w_init(void) { return rw_init(0); } /* write-behind */ 78 struct tftphdr *r_init(void) { return rw_init(1); } /* read-ahead */ 79 80 static struct tftphdr * 81 rw_init(int x /* zero for write-behind, one for read-head */ 82 ) /* init for either read-ahead or write-behind */ 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 int 98 readit(FILE *file, /* file opened for read */ 99 struct tftphdr **dpp, 100 int convert /* if true, convert to ascii */ 101 ) 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 void 121 read_ahead(FILE *file, int convert) 122 { 123 int i; 124 char *p; 125 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 int 168 writeit(FILE *file, struct tftphdr **dpp, int ct, int convert) 169 { 170 bfs[current].counter = ct; /* set size of data to write */ 171 current = !current; /* switch to other buffer */ 172 if (bfs[current].counter != BF_FREE) /* if not free */ 173 (void)write_behind(file, convert); /* flush it */ 174 bfs[current].counter = BF_ALLOC; /* mark as alloc'd */ 175 *dpp = (struct tftphdr *)bfs[current].buf; 176 return ct; /* this is a lie of course */ 177 } 178 179 /* 180 * Output a buffer to a file, converting from netascii if requested. 181 * CR,NUL -> CR and CR,LF => LF. 182 * Note spec is undefined if we get CR as last byte of file or a 183 * CR followed by anything else. In this case we leave it alone. 184 */ 185 int 186 write_behind(FILE *file, int convert) 187 { 188 char *buf; 189 int count; 190 int ct; 191 char *p; 192 int c; /* current character */ 193 struct bf *b; 194 struct tftphdr *dp; 195 196 b = &bfs[nextone]; 197 if (b->counter < -1) /* anything to flush? */ 198 return 0; /* just nop if nothing to do */ 199 200 count = b->counter; /* remember byte count */ 201 b->counter = BF_FREE; /* reset flag */ 202 dp = (struct tftphdr *)b->buf; 203 nextone = !nextone; /* incr for next time */ 204 buf = dp->th_data; 205 206 if (count <= 0) return -1; /* nak logic? */ 207 208 if (convert == 0) 209 return write(fileno(file), buf, count); 210 211 p = buf; 212 ct = count; 213 while (ct--) { /* loop over the buffer */ 214 c = *p++; /* pick up a character */ 215 if (prevchar == '\r') { /* if prev char was cr */ 216 if (c == '\n') /* if have cr,lf then just */ 217 fseek(file, -1, 1); /* smash lf on top of the cr */ 218 else 219 if (c == '\0') /* if have cr,nul then */ 220 goto skipit; /* just skip over the putc */ 221 /* else just fall through and allow it */ 222 } 223 putc(c, file); 224 skipit: 225 prevchar = c; 226 } 227 return count; 228 } 229 230 231 /* When an error has occurred, it is possible that the two sides 232 * are out of synch. Ie: that what I think is the other side's 233 * response to packet N is really their response to packet N-1. 234 * 235 * So, to try to prevent that, we flush all the input queued up 236 * for us on the network connection on our host. 237 * 238 * We return the number of packets we flushed (mostly for reporting 239 * when trace is active). 240 */ 241 242 int 243 synchnet(int f) 244 { 245 int i, j = 0; 246 char rbuf[PKTSIZE]; 247 struct sockaddr_storage from; 248 int fromlen; 249 250 while (1) { 251 (void) ioctl(f, FIONREAD, &i); 252 if (i) { 253 j++; 254 fromlen = sizeof from; 255 (void) recvfrom(f, rbuf, sizeof (rbuf), 0, 256 (struct sockaddr *)&from, &fromlen); 257 } else { 258 return(j); 259 } 260 } 261 } 262