Lorenzo Colitti | 313379e | 2013-07-11 01:07:11 +0900 | [diff] [blame] | 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 <unistd.h> |
| 55 | #include <stdio.h> |
| 56 | |
| 57 | #include "tftp.h" |
| 58 | |
| 59 | #define PKTSIZE SEGSIZE+4 /* should be moved to tftp.h */ |
| 60 | |
| 61 | struct bf { |
| 62 | int counter; /* size of data in buffer, or flag */ |
| 63 | char buf[PKTSIZE]; /* room for data packet */ |
| 64 | } bfs[2]; |
| 65 | |
| 66 | /* Values for bf.counter */ |
| 67 | #define BF_ALLOC -3 /* alloc'd but not yet filled */ |
| 68 | #define BF_FREE -2 /* free */ |
| 69 | /* [-1 .. SEGSIZE] = size of data in the data buffer */ |
| 70 | |
| 71 | static int nextone; /* index of next buffer to use */ |
| 72 | static int current; /* index of buffer in use */ |
| 73 | |
| 74 | /* control flags for crlf conversions */ |
| 75 | int newline = 0; /* fillbuf: in middle of newline expansion */ |
| 76 | int prevchar = -1; /* putbuf: previous char (cr check) */ |
| 77 | |
| 78 | struct tftphdr *rw_init(int); |
| 79 | |
| 80 | struct tftphdr *w_init() { return rw_init(0); } /* write-behind */ |
| 81 | struct tftphdr *r_init() { return rw_init(1); } /* read-ahead */ |
| 82 | |
| 83 | /* init for either read-ahead or write-behind */ |
| 84 | /* x is zero for write-behind, one for read-head */ |
| 85 | struct tftphdr *rw_init(int x) |
| 86 | { |
| 87 | newline = 0; /* init crlf flag */ |
| 88 | prevchar = -1; |
| 89 | bfs[0].counter = BF_ALLOC; /* pass out the first buffer */ |
| 90 | current = 0; |
| 91 | bfs[1].counter = BF_FREE; |
| 92 | nextone = x; /* ahead or behind? */ |
| 93 | return (struct tftphdr *)bfs[0].buf; |
| 94 | } |
| 95 | |
| 96 | |
| 97 | /* Have emptied current buffer by sending to net and getting ack. |
| 98 | Free it and return next buffer filled with data. |
| 99 | */ |
| 100 | int readit(FILE * file, struct tftphdr **dpp, int convert) |
| 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 | #if 0 |
| 111 | assert(b->counter != BF_FREE); /* check */ |
| 112 | #endif |
| 113 | *dpp = (struct tftphdr *)b->buf; /* set caller's ptr */ |
| 114 | return b->counter; |
| 115 | } |
| 116 | |
| 117 | /* |
| 118 | * fill the input buffer, doing ascii conversions if requested |
| 119 | * conversions are lf -> cr,lf and cr -> cr, nul |
| 120 | */ |
| 121 | void read_ahead(FILE *file, int convert) |
| 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 | int writeit(FILE *file, struct tftphdr **dpp, int ct, int convert) |
| 168 | { |
| 169 | bfs[current].counter = ct; /* set size of data to write */ |
| 170 | current = !current; /* switch to other buffer */ |
| 171 | if (bfs[current].counter != BF_FREE) /* if not free */ |
| 172 | write_behind(file, convert); /* flush it */ |
| 173 | bfs[current].counter = BF_ALLOC; /* mark as alloc'd */ |
| 174 | *dpp = (struct tftphdr *)bfs[current].buf; |
| 175 | return ct; /* this is a lie of course */ |
| 176 | } |
| 177 | |
| 178 | /* |
| 179 | * Output a buffer to a file, converting from netascii if requested. |
| 180 | * CR,NUL -> CR and CR,LF => LF. |
| 181 | * Note spec is undefined if we get CR as last byte of file or a |
| 182 | * CR followed by anything else. In this case we leave it alone. |
| 183 | */ |
| 184 | int write_behind(FILE *file, int convert) |
| 185 | { |
| 186 | char *buf; |
| 187 | int count; |
| 188 | register int ct; |
| 189 | register char *p; |
| 190 | register int c; /* current character */ |
| 191 | struct bf *b; |
| 192 | struct tftphdr *dp; |
| 193 | |
| 194 | b = &bfs[nextone]; |
| 195 | if (b->counter < -1) /* anything to flush? */ |
| 196 | return 0; /* just nop if nothing to do */ |
| 197 | |
| 198 | count = b->counter; /* remember byte count */ |
| 199 | b->counter = BF_FREE; /* reset flag */ |
| 200 | dp = (struct tftphdr *)b->buf; |
| 201 | nextone = !nextone; /* incr for next time */ |
| 202 | buf = dp->th_data; |
| 203 | |
| 204 | if (count <= 0) return -1; /* nak logic? */ |
| 205 | |
| 206 | if (convert == 0) |
| 207 | return write(fileno(file), buf, count); |
| 208 | |
| 209 | p = buf; |
| 210 | ct = count; |
| 211 | while (ct--) { /* loop over the buffer */ |
| 212 | c = *p++; /* pick up a character */ |
| 213 | if (prevchar == '\r') { /* if prev char was cr */ |
| 214 | if (c == '\n') /* if have cr,lf then just */ |
| 215 | fseek(file, -1, 1); /* smash lf on top of the cr */ |
| 216 | else |
| 217 | if (c == '\0') /* if have cr,nul then */ |
| 218 | goto skipit; /* just skip over the putc */ |
| 219 | /* else just fall through and allow it */ |
| 220 | } |
| 221 | putc(c, file); |
| 222 | skipit: |
| 223 | prevchar = c; |
| 224 | } |
| 225 | return count; |
| 226 | } |
| 227 | |
| 228 | |
| 229 | /* When an error has occurred, it is possible that the two sides |
| 230 | * are out of synch. Ie: that what I think is the other side's |
| 231 | * response to packet N is really their response to packet N-1. |
| 232 | * |
| 233 | * So, to try to prevent that, we flush all the input queued up |
| 234 | * for us on the network connection on our host. |
| 235 | * |
| 236 | * We return the number of packets we flushed (mostly for reporting |
| 237 | * when trace is active). |
| 238 | */ |
| 239 | |
| 240 | int synchnet(int f) |
| 241 | { |
| 242 | int j = 0; |
| 243 | char dummy; |
| 244 | |
| 245 | while (1) { |
| 246 | if (recv(f, &dummy, 1, MSG_DONTWAIT) < 0) |
| 247 | break; |
| 248 | j++; |
| 249 | } |
| 250 | return j; |
| 251 | } |