tftp.tproj/tftpsubs.c

   1 /*
   2  * Copyright (c) 1999 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_LICENSE_HEADER_START@
   5  *
   6  * Copyright (c) 1999-2003 Apple Computer, Inc.  All Rights Reserved.
   7  *
   8  * This file contains Original Code and/or Modifications of Original Code
   9  * as defined in and that are subject to the Apple Public Source License
  10  * Version 2.0 (the 'License'). You may not use this file except in
  11  * compliance with the License. Please obtain a copy of the License at
  12  * http://www.opensource.apple.com/apsl/ and read it before using this
  13  * file.
  14  *
  15  * The Original Code and all software distributed under the License are
  16  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  17  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  18  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  19  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  20  * Please see the License for the specific language governing rights and
  21  * limitations under the License.
  22  *
  23  * @APPLE_LICENSE_HEADER_END@
  24  */
  25 /*
  26  * Copyright (c) 1983, 1993
  27  *      The Regents of the University of California.  All rights reserved.
  28  *
  29  * Redistribution and use in source and binary forms, with or without
  30  * modification, are permitted provided that the following conditions
  31  * are met:
  32  * 1. Redistributions of source code must retain the above copyright
  33  *    notice, this list of conditions and the following disclaimer.
  34  * 2. Redistributions in binary form must reproduce the above copyright
  35  *    notice, this list of conditions and the following disclaimer in the
  36  *    documentation and/or other materials provided with the distribution.
  37  * 3. All advertising materials mentioning features or use of this software
  38  *    must display the following acknowledgement:
  39  *      This product includes software developed by the University of
  40  *      California, Berkeley and its contributors.
  41  * 4. Neither the name of the University nor the names of its contributors
  42  *    may be used to endorse or promote products derived from this software
  43  *    without specific prior written permission.
  44  *
  45  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  46  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  47  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  48  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  49  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  50  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  51  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  52  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  53  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  54  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  55  * SUCH DAMAGE.
  56  */
  57
  58
  59 /* Simple minded read-ahead/write-behind subroutines for tftp user and
  60    server.  Written originally with multiple buffers in mind, but current
  61    implementation has two buffer logic wired in.
  62
  63    Todo:  add some sort of final error check so when the write-buffer
  64    is finally flushed, the caller can detect if the disk filled up
  65    (or had an i/o error) and return a nak to the other side.
  66
  67                         Jim Guyton 10/85
  68  */
  69
  70 #include <sys/types.h>
  71 #include <sys/socket.h>
  72 #include <sys/ioctl.h>
  73 #include <netinet/in.h>
  74 #include <arpa/tftp.h>
  75
  76 #include <stdio.h>
  77 #include <unistd.h>
  78
  79 #include "tftpsubs.h"
  80
  81 #define PKTSIZE SEGSIZE+4       /* should be moved to tftp.h */
  82
  83 struct bf {
  84         int counter;            /* size of data in buffer, or flag */
  85         char buf[PKTSIZE];      /* room for data packet */
  86 } bfs[2];
  87
  88                                 /* Values for bf.counter  */
  89 #define BF_ALLOC -3             /* alloc'd but not yet filled */
  90 #define BF_FREE  -2             /* free */
  91 /* [-1 .. SEGSIZE] = size of data in the data buffer */
  92
  93 static int nextone;             /* index of next buffer to use */
  94 static int current;             /* index of buffer in use */
  95
  96                                 /* control flags for crlf conversions */
  97 int newline = 0;                /* fillbuf: in middle of newline expansion */
  98 int prevchar = -1;              /* putbuf: previous char (cr check) */
  99
 100 static struct tftphdr *rw_init();
 101
 102 struct tftphdr *w_init() { return rw_init(0); }         /* write-behind */
 103 struct tftphdr *r_init() { return rw_init(1); }         /* read-ahead */
 104
 105 static struct tftphdr *
 106 rw_init(x)                      /* init for either read-ahead or write-behind */
 107         int x;                  /* zero for write-behind, one for read-head */
 108 {
 109         newline = 0;            /* init crlf flag */
 110         prevchar = -1;
 111         bfs[0].counter =  BF_ALLOC;     /* pass out the first buffer */
 112         current = 0;
 113         bfs[1].counter = BF_FREE;
 114         nextone = x;                    /* ahead or behind? */
 115         return (struct tftphdr *)bfs[0].buf;
 116 }
 117
 118
 119 /* Have emptied current buffer by sending to net and getting ack.
 120    Free it and return next buffer filled with data.
 121  */
 122 int
 123 readit(file, dpp, convert)
 124         FILE *file;                     /* file opened for read */
 125         struct tftphdr **dpp;
 126         int convert;                    /* if true, convert to ascii */
 127 {
 128         struct bf *b;
 129
 130         bfs[current].counter = BF_FREE; /* free old one */
 131         current = !current;             /* "incr" current */
 132
 133         b = &bfs[current];              /* look at new buffer */
 134         if (b->counter == BF_FREE)      /* if it's empty */
 135                 read_ahead(file, convert);      /* fill it */
 136 /*      assert(b->counter != BF_FREE);*//* check */
 137         *dpp = (struct tftphdr *)b->buf;        /* set caller's ptr */
 138         return b->counter;
 139 }
 140
 141 /*
 142  * fill the input buffer, doing ascii conversions if requested
 143  * conversions are  lf -> cr,lf  and cr -> cr, nul
 144  */
 145 void
 146 read_ahead(file, convert)
 147         FILE *file;                     /* file opened for read */
 148         int convert;                    /* if true, convert to ascii */
 149 {
 150         register int i;
 151         register char *p;
 152         register int c;
 153         struct bf *b;
 154         struct tftphdr *dp;
 155
 156         b = &bfs[nextone];              /* look at "next" buffer */
 157         if (b->counter != BF_FREE)      /* nop if not free */
 158                 return;
 159         nextone = !nextone;             /* "incr" next buffer ptr */
 160
 161         dp = (struct tftphdr *)b->buf;
 162
 163         if (convert == 0) {
 164                 b->counter = read(fileno(file), dp->th_data, SEGSIZE);
 165                 return;
 166         }
 167
 168         p = dp->th_data;
 169         for (i = 0 ; i < SEGSIZE; i++) {
 170                 if (newline) {
 171                         if (prevchar == '\n')
 172                                 c = '\n';       /* lf to cr,lf */
 173                         else    c = '\0';       /* cr to cr,nul */
 174                         newline = 0;
 175                 }
 176                 else {
 177                         c = getc(file);
 178                         if (c == EOF) break;
 179                         if (c == '\n' || c == '\r') {
 180                                 prevchar = c;
 181                                 c = '\r';
 182                                 newline = 1;
 183                         }
 184                 }
 185                *p++ = c;
 186         }
 187         b->counter = (int)(p - dp->th_data);
 188 }
 189
 190 /* Update count associated with the buffer, get new buffer
 191    from the queue.  Calls write_behind only if next buffer not
 192    available.
 193  */
 194 int
 195 writeit(file, dpp, ct, convert)
 196         FILE *file;
 197         struct tftphdr **dpp;
 198         int ct, convert;
 199 {
 200         bfs[current].counter = ct;      /* set size of data to write */
 201         current = !current;             /* switch to other buffer */
 202         if (bfs[current].counter != BF_FREE)     /* if not free */
 203                 (void)write_behind(file, convert); /* flush it */
 204         bfs[current].counter = BF_ALLOC;        /* mark as alloc'd */
 205         *dpp =  (struct tftphdr *)bfs[current].buf;
 206         return ct;                      /* this is a lie of course */
 207 }
 208
 209 /*
 210  * Output a buffer to a file, converting from netascii if requested.
 211  * CR,NUL -> CR  and CR,LF => LF.
 212  * Note spec is undefined if we get CR as last byte of file or a
 213  * CR followed by anything else.  In this case we leave it alone.
 214  */
 215 int
 216 write_behind(file, convert)
 217         FILE *file;
 218         int convert;
 219 {
 220         char *buf;
 221         int count;
 222         register int ct;
 223         register char *p;
 224         register int c;                 /* current character */
 225         struct bf *b;
 226         struct tftphdr *dp;
 227
 228         b = &bfs[nextone];
 229         if (b->counter < -1)            /* anything to flush? */
 230                 return 0;               /* just nop if nothing to do */
 231
 232         count = b->counter;             /* remember byte count */
 233         b->counter = BF_FREE;           /* reset flag */
 234         dp = (struct tftphdr *)b->buf;
 235         nextone = !nextone;             /* incr for next time */
 236         buf = dp->th_data;
 237
 238         if (count <= 0) return -1;      /* nak logic? */
 239
 240         if (convert == 0)
 241                 return write(fileno(file), buf, count);
 242
 243         p = buf;
 244         ct = count;
 245         while (ct--) {                  /* loop over the buffer */
 246             c = *p++;                   /* pick up a character */
 247             if (prevchar == '\r') {     /* if prev char was cr */
 248                 if (c == '\n')          /* if have cr,lf then just */
 249                    fseek(file, -1, 1);  /* smash lf on top of the cr */
 250                 else
 251                    if (c == '\0')       /* if have cr,nul then */
 252                         goto skipit;    /* just skip over the putc */
 253                 /* else just fall through and allow it */
 254             }
 255             putc(c, file);
 256 skipit:
 257             prevchar = c;
 258         }
 259         return count;
 260 }
 261
 262
 263 /* When an error has occurred, it is possible that the two sides
 264  * are out of synch.  Ie: that what I think is the other side's
 265  * response to packet N is really their response to packet N-1.
 266  *
 267  * So, to try to prevent that, we flush all the input queued up
 268  * for us on the network connection on our host.
 269  *
 270  * We return the number of packets we flushed (mostly for reporting
 271  * when trace is active).
 272  */
 273
 274 int
 275 synchnet(f)
 276         int     f;              /* socket to flush */
 277 {
 278         int i, j = 0;
 279         char rbuf[PKTSIZE];
 280         struct sockaddr_in from;
 281         int fromlen;
 282
 283         while (1) {
 284                 (void) ioctl(f, FIONREAD, &i);
 285                 if (i) {
 286                         j++;
 287                         fromlen = sizeof from;
 288                         (void) recvfrom(f, rbuf, sizeof (rbuf), 0,
 289                                 (struct sockaddr *)&from, &fromlen);
 290                 } else {
 291                         return(j);
 292                 }
 293         }
 294 }