remote_cmds/tftp.tproj/tftpsubs.c

   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
  34 #include <sys/cdefs.h>
  35
  36 __FBSDID("$FreeBSD: src/usr.bin/tftp/tftpsubs.c,v 1.6 2005/02/14 17:42:58 stefanf Exp $");
  37
  38 #ifndef lint
  39 __attribute__((__used__))
  40 static const char sccsid[] = "@(#)tftpsubs.c    8.1 (Berkeley) 6/6/93";
  41 #endif
  42
  43 /* Simple minded read-ahead/write-behind subroutines for tftp user and
  44    server.  Written originally with multiple buffers in mind, but current
  45    implementation has two buffer logic wired in.
  46
  47    Todo:  add some sort of final error check so when the write-buffer
  48    is finally flushed, the caller can detect if the disk filled up
  49    (or had an i/o error) and return a nak to the other side.
  50
  51                         Jim Guyton 10/85
  52  */
  53
  54 #include <sys/types.h>
  55 #include <sys/socket.h>
  56 #include <sys/ioctl.h>
  57 #include <netinet/in.h>
  58 #include <arpa/tftp.h>
  59
  60 #include <stdio.h>
  61 #include <unistd.h>
  62
  63 #include "tftpsubs.h"
  64
  65 #ifdef __APPLE__
  66 struct bf {
  67         int counter;            /* size of data in buffer, or flag */
  68         char buf[MAXPKTSIZE];   /* room for data packet */
  69 } bfs[2];
  70 #else
  71 #define PKTSIZE SEGSIZE+4       /* should be moved to tftp.h */
  72
  73 struct bf {
  74         int counter;            /* size of data in buffer, or flag */
  75         char buf[PKTSIZE];      /* room for data packet */
  76 } bfs[2];
  77 #endif
  78
  79                                 /* Values for bf.counter  */
  80 #define BF_ALLOC -3             /* alloc'd but not yet filled */
  81 #define BF_FREE  -2             /* free */
  82 /* [-1 .. SEGSIZE] = size of data in the data buffer */
  83
  84 static int nextone;             /* index of next buffer to use */
  85 static int current;             /* index of buffer in use */
  86
  87                                 /* control flags for crlf conversions */
  88 int newline = 0;                /* fillbuf: in middle of newline expansion */
  89 int prevchar = -1;              /* putbuf: previous char (cr check) */
  90
  91 static struct tftphdr *rw_init(int);
  92
  93 struct tftphdr *w_init(void) { return rw_init(0); }         /* write-behind */
  94 struct tftphdr *r_init(void) { return rw_init(1); }         /* read-ahead */
  95
  96 static struct tftphdr *
  97 rw_init(x)                      /* init for either read-ahead or write-behind */
  98         int x;                  /* zero for write-behind, one for read-head */
  99 {
 100         newline = 0;            /* init crlf flag */
 101         prevchar = -1;
 102         bfs[0].counter =  BF_ALLOC;     /* pass out the first buffer */
 103         current = 0;
 104         bfs[1].counter = BF_FREE;
 105         nextone = x;                    /* ahead or behind? */
 106         return (struct tftphdr *)bfs[0].buf;
 107 }
 108
 109
 110 /* Have emptied current buffer by sending to net and getting ack.
 111    Free it and return next buffer filled with data.
 112  */
 113 int
 114 readit(file, dpp, amt, convert)
 115         FILE *file;                     /* file opened for read */
 116         struct tftphdr **dpp;
 117         int amt;
 118         int convert;                    /* if true, convert to ascii */
 119 {
 120         struct bf *b;
 121
 122         bfs[current].counter = BF_FREE; /* free old one */
 123         current = !current;             /* "incr" current */
 124
 125         b = &bfs[current];              /* look at new buffer */
 126         if (b->counter == BF_FREE)      /* if it's empty */
 127                 read_ahead(file, amt, convert);      /* fill it */
 128 /*      assert(b->counter != BF_FREE);*//* check */
 129         *dpp = (struct tftphdr *)b->buf;        /* set caller's ptr */
 130         return b->counter;
 131 }
 132
 133 /*
 134  * fill the input buffer, doing ascii conversions if requested
 135  * conversions are  lf -> cr,lf  and cr -> cr, nul
 136  */
 137 void
 138 read_ahead(file, amt, convert)
 139         FILE *file;                     /* file opened for read */
 140         int amt;                        /* number of bytes to read */
 141         int convert;                    /* if true, convert to ascii */
 142 {
 143         int i;
 144         char *p;
 145         int c;
 146         struct bf *b;
 147         struct tftphdr *dp;
 148
 149         b = &bfs[nextone];              /* look at "next" buffer */
 150         if (b->counter != BF_FREE)      /* nop if not free */
 151                 return;
 152         nextone = !nextone;             /* "incr" next buffer ptr */
 153
 154         dp = (struct tftphdr *)b->buf;
 155
 156         if (convert == 0) {
 157                 b->counter = read(fileno(file), dp->th_data, amt);
 158                 return;
 159         }
 160
 161         p = dp->th_data;
 162         for (i = 0 ; i < amt; i++) {
 163                 if (newline) {
 164                         if (prevchar == '\n')
 165                                 c = '\n';       /* lf to cr,lf */
 166                         else    c = '\0';       /* cr to cr,nul */
 167                         newline = 0;
 168                 }
 169                 else {
 170                         c = getc(file);
 171                         if (c == EOF) break;
 172                         if (c == '\n' || c == '\r') {
 173                                 prevchar = c;
 174                                 c = '\r';
 175                                 newline = 1;
 176                         }
 177                 }
 178                *p++ = c;
 179         }
 180         b->counter = (int)(p - dp->th_data);
 181 }
 182
 183 /* Update count associated with the buffer, get new buffer
 184    from the queue.  Calls write_behind only if next buffer not
 185    available.
 186  */
 187 int
 188 writeit(file, dpp, ct, convert)
 189         FILE *file;
 190         struct tftphdr **dpp;
 191         int ct, convert;
 192 {
 193         bfs[current].counter = ct;      /* set size of data to write */
 194         current = !current;             /* switch to other buffer */
 195         if (bfs[current].counter != BF_FREE)     /* if not free */
 196                 (void)write_behind(file, convert); /* flush it */
 197         bfs[current].counter = BF_ALLOC;        /* mark as alloc'd */
 198         *dpp =  (struct tftphdr *)bfs[current].buf;
 199         return ct;                      /* this is a lie of course */
 200 }
 201
 202 /*
 203  * Output a buffer to a file, converting from netascii if requested.
 204  * CR,NUL -> CR  and CR,LF => LF.
 205  * Note spec is undefined if we get CR as last byte of file or a
 206  * CR followed by anything else.  In this case we leave it alone.
 207  */
 208 int
 209 write_behind(file, convert)
 210         FILE *file;
 211         int convert;
 212 {
 213         char *buf;
 214         int count;
 215         int ct;
 216         char *p;
 217         int c;                 /* current character */
 218         struct bf *b;
 219         struct tftphdr *dp;
 220
 221         b = &bfs[nextone];
 222         if (b->counter < -1)            /* anything to flush? */
 223                 return 0;               /* just nop if nothing to do */
 224
 225         count = b->counter;             /* remember byte count */
 226         b->counter = BF_FREE;           /* reset flag */
 227         dp = (struct tftphdr *)b->buf;
 228         nextone = !nextone;             /* incr for next time */
 229         buf = dp->th_data;
 230
 231         if (count <= 0) return -1;      /* nak logic? */
 232
 233         if (convert == 0)
 234                 return write(fileno(file), buf, count);
 235
 236         p = buf;
 237         ct = count;
 238         while (ct--) {                  /* loop over the buffer */
 239             c = *p++;                   /* pick up a character */
 240             if (prevchar == '\r') {     /* if prev char was cr */
 241                 if (c == '\n')          /* if have cr,lf then just */
 242                    fseek(file, -1, 1);  /* smash lf on top of the cr */
 243                 else
 244                    if (c == '\0')       /* if have cr,nul then */
 245                         goto skipit;    /* just skip over the putc */
 246                 /* else just fall through and allow it */
 247             }
 248             putc(c, file);
 249 skipit:
 250             prevchar = c;
 251         }
 252         return count;
 253 }
 254
 255
 256 /* When an error has occurred, it is possible that the two sides
 257  * are out of synch.  Ie: that what I think is the other side's
 258  * response to packet N is really their response to packet N-1.
 259  *
 260  * So, to try to prevent that, we flush all the input queued up
 261  * for us on the network connection on our host.
 262  *
 263  * We return the number of packets we flushed (mostly for reporting
 264  * when trace is active).
 265  */
 266
 267 int
 268 synchnet(f)
 269         int     f;              /* socket to flush */
 270 {
 271         int i, j = 0;
 272         char rbuf[PKTSIZE];
 273         struct sockaddr_storage from;
 274         socklen_t fromlen;
 275
 276         while (1) {
 277                 (void) ioctl(f, FIONREAD, &i);
 278                 if (i) {
 279                         j++;
 280                         fromlen = sizeof from;
 281                         (void) recvfrom(f, rbuf, sizeof (rbuf), 0,
 282                                 (struct sockaddr *)&from, &fromlen);
 283                 } else {
 284                         return(j);
 285                 }
 286         }
 287 }