tftp.tproj/tftpsubs.c

   1 /*
   2  * Copyright (c) 1999 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_LICENSE_HEADER_START@
   5  *
   6  * "Portions Copyright (c) 1999 Apple Computer, Inc.  All Rights
   7  * Reserved.  This file contains Original Code and/or Modifications of
   8  * Original Code as defined in and that are subject to the Apple Public
   9  * Source License Version 1.0 (the 'License').  You may not use this file
  10  * except in compliance with the License.  Please obtain a copy of the
  11  * License at http://www.apple.com/publicsource and read it before using
  12  * this file.
  13  *
  14  * The Original Code and all software distributed under the License are
  15  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  16  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  17  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  18  * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT.  Please see the
  19  * License for the specific language governing rights and limitations
  20  * under the License."
  21  *
  22  * @APPLE_LICENSE_HEADER_END@
  23  */
  24 /*
  25  * Copyright (c) 1983, 1993
  26  *      The Regents of the University of California.  All rights reserved.
  27  *
  28  * Redistribution and use in source and binary forms, with or without
  29  * modification, are permitted provided that the following conditions
  30  * are met:
  31  * 1. Redistributions of source code must retain the above copyright
  32  *    notice, this list of conditions and the following disclaimer.
  33  * 2. Redistributions in binary form must reproduce the above copyright
  34  *    notice, this list of conditions and the following disclaimer in the
  35  *    documentation and/or other materials provided with the distribution.
  36  * 3. All advertising materials mentioning features or use of this software
  37  *    must display the following acknowledgement:
  38  *      This product includes software developed by the University of
  39  *      California, Berkeley and its contributors.
  40  * 4. Neither the name of the University nor the names of its contributors
  41  *    may be used to endorse or promote products derived from this software
  42  *    without specific prior written permission.
  43  *
  44  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  45  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  46  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  47  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  48  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  49  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  50  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  51  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  52  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  53  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  54  * SUCH DAMAGE.
  55  */
  56
  57
  58 /* Simple minded read-ahead/write-behind subroutines for tftp user and
  59    server.  Written originally with multiple buffers in mind, but current
  60    implementation has two buffer logic wired in.
  61
  62    Todo:  add some sort of final error check so when the write-buffer
  63    is finally flushed, the caller can detect if the disk filled up
  64    (or had an i/o error) and return a nak to the other side.
  65
  66                         Jim Guyton 10/85
  67  */
  68
  69 #include <sys/types.h>
  70 #include <sys/socket.h>
  71 #include <sys/ioctl.h>
  72 #include <netinet/in.h>
  73 #include <arpa/tftp.h>
  74
  75 #include <stdio.h>
  76 #include <unistd.h>
  77
  78 #include "tftpsubs.h"
  79
  80 #define PKTSIZE SEGSIZE+4       /* should be moved to tftp.h */
  81
  82 struct bf {
  83         int counter;            /* size of data in buffer, or flag */
  84         char buf[PKTSIZE];      /* room for data packet */
  85 } bfs[2];
  86
  87                                 /* Values for bf.counter  */
  88 #define BF_ALLOC -3             /* alloc'd but not yet filled */
  89 #define BF_FREE  -2             /* free */
  90 /* [-1 .. SEGSIZE] = size of data in the data buffer */
  91
  92 static int nextone;             /* index of next buffer to use */
  93 static int current;             /* index of buffer in use */
  94
  95                                 /* control flags for crlf conversions */
  96 int newline = 0;                /* fillbuf: in middle of newline expansion */
  97 int prevchar = -1;              /* putbuf: previous char (cr check) */
  98
  99 static struct tftphdr *rw_init();
 100
 101 struct tftphdr *w_init() { return rw_init(0); }         /* write-behind */
 102 struct tftphdr *r_init() { return rw_init(1); }         /* read-ahead */
 103
 104 static struct tftphdr *
 105 rw_init(x)                      /* init for either read-ahead or write-behind */
 106         int x;                  /* zero for write-behind, one for read-head */
 107 {
 108         newline = 0;            /* init crlf flag */
 109         prevchar = -1;
 110         bfs[0].counter =  BF_ALLOC;     /* pass out the first buffer */
 111         current = 0;
 112         bfs[1].counter = BF_FREE;
 113         nextone = x;                    /* ahead or behind? */
 114         return (struct tftphdr *)bfs[0].buf;
 115 }
 116
 117
 118 /* Have emptied current buffer by sending to net and getting ack.
 119    Free it and return next buffer filled with data.
 120  */
 121 int
 122 readit(file, dpp, convert)
 123         FILE *file;                     /* file opened for read */
 124         struct tftphdr **dpp;
 125         int convert;                    /* if true, convert to ascii */
 126 {
 127         struct bf *b;
 128
 129         bfs[current].counter = BF_FREE; /* free old one */
 130         current = !current;             /* "incr" current */
 131
 132         b = &bfs[current];              /* look at new buffer */
 133         if (b->counter == BF_FREE)      /* if it's empty */
 134                 read_ahead(file, convert);      /* fill it */
 135 /*      assert(b->counter != BF_FREE);*//* check */
 136         *dpp = (struct tftphdr *)b->buf;        /* set caller's ptr */
 137         return b->counter;
 138 }
 139
 140 /*
 141  * fill the input buffer, doing ascii conversions if requested
 142  * conversions are  lf -> cr,lf  and cr -> cr, nul
 143  */
 144 void
 145 read_ahead(file, convert)
 146         FILE *file;                     /* file opened for read */
 147         int convert;                    /* if true, convert to ascii */
 148 {
 149         register int i;
 150         register char *p;
 151         register int c;
 152         struct bf *b;
 153         struct tftphdr *dp;
 154
 155         b = &bfs[nextone];              /* look at "next" buffer */
 156         if (b->counter != BF_FREE)      /* nop if not free */
 157                 return;
 158         nextone = !nextone;             /* "incr" next buffer ptr */
 159
 160         dp = (struct tftphdr *)b->buf;
 161
 162         if (convert == 0) {
 163                 b->counter = read(fileno(file), dp->th_data, SEGSIZE);
 164                 return;
 165         }
 166
 167         p = dp->th_data;
 168         for (i = 0 ; i < SEGSIZE; i++) {
 169                 if (newline) {
 170                         if (prevchar == '\n')
 171                                 c = '\n';       /* lf to cr,lf */
 172                         else    c = '\0';       /* cr to cr,nul */
 173                         newline = 0;
 174                 }
 175                 else {
 176                         c = getc(file);
 177                         if (c == EOF) break;
 178                         if (c == '\n' || c == '\r') {
 179                                 prevchar = c;
 180                                 c = '\r';
 181                                 newline = 1;
 182                         }
 183                 }
 184                *p++ = c;
 185         }
 186         b->counter = (int)(p - dp->th_data);
 187 }
 188
 189 /* Update count associated with the buffer, get new buffer
 190    from the queue.  Calls write_behind only if next buffer not
 191    available.
 192  */
 193 int
 194 writeit(file, dpp, ct, convert)
 195         FILE *file;
 196         struct tftphdr **dpp;
 197         int ct, convert;
 198 {
 199         bfs[current].counter = ct;      /* set size of data to write */
 200         current = !current;             /* switch to other buffer */
 201         if (bfs[current].counter != BF_FREE)     /* if not free */
 202                 (void)write_behind(file, convert); /* flush it */
 203         bfs[current].counter = BF_ALLOC;        /* mark as alloc'd */
 204         *dpp =  (struct tftphdr *)bfs[current].buf;
 205         return ct;                      /* this is a lie of course */
 206 }
 207
 208 /*
 209  * Output a buffer to a file, converting from netascii if requested.
 210  * CR,NUL -> CR  and CR,LF => LF.
 211  * Note spec is undefined if we get CR as last byte of file or a
 212  * CR followed by anything else.  In this case we leave it alone.
 213  */
 214 int
 215 write_behind(file, convert)
 216         FILE *file;
 217         int convert;
 218 {
 219         char *buf;
 220         int count;
 221         register int ct;
 222         register char *p;
 223         register int c;                 /* current character */
 224         struct bf *b;
 225         struct tftphdr *dp;
 226
 227         b = &bfs[nextone];
 228         if (b->counter < -1)            /* anything to flush? */
 229                 return 0;               /* just nop if nothing to do */
 230
 231         count = b->counter;             /* remember byte count */
 232         b->counter = BF_FREE;           /* reset flag */
 233         dp = (struct tftphdr *)b->buf;
 234         nextone = !nextone;             /* incr for next time */
 235         buf = dp->th_data;
 236
 237         if (count <= 0) return -1;      /* nak logic? */
 238
 239         if (convert == 0)
 240                 return write(fileno(file), buf, count);
 241
 242         p = buf;
 243         ct = count;
 244         while (ct--) {                  /* loop over the buffer */
 245             c = *p++;                   /* pick up a character */
 246             if (prevchar == '\r') {     /* if prev char was cr */
 247                 if (c == '\n')          /* if have cr,lf then just */
 248                    fseek(file, -1, 1);  /* smash lf on top of the cr */
 249                 else
 250                    if (c == '\0')       /* if have cr,nul then */
 251                         goto skipit;    /* just skip over the putc */
 252                 /* else just fall through and allow it */
 253             }
 254             putc(c, file);
 255 skipit:
 256             prevchar = c;
 257         }
 258         return count;
 259 }
 260
 261
 262 /* When an error has occurred, it is possible that the two sides
 263  * are out of synch.  Ie: that what I think is the other side's
 264  * response to packet N is really their response to packet N-1.
 265  *
 266  * So, to try to prevent that, we flush all the input queued up
 267  * for us on the network connection on our host.
 268  *
 269  * We return the number of packets we flushed (mostly for reporting
 270  * when trace is active).
 271  */
 272
 273 int
 274 synchnet(f)
 275         int     f;              /* socket to flush */
 276 {
 277         int i, j = 0;
 278         char rbuf[PKTSIZE];
 279         struct sockaddr_in from;
 280         int fromlen;
 281
 282         while (1) {
 283                 (void) ioctl(f, FIONREAD, &i);
 284                 if (i) {
 285                         j++;
 286                         fromlen = sizeof from;
 287                         (void) recvfrom(f, rbuf, sizeof (rbuf), 0,
 288                                 (struct sockaddr *)&from, &fromlen);
 289                 } else {
 290                         return(j);
 291                 }
 292         }
 293 }