summaryrefslogtreecommitdiffstats
path: root/usr.bin/tftp/tftpsubs.c
blob: 5f3549d7dcf89247fa25bdc51d6a9b9e7d475ab6 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
/*
 * Copyright (c) 1983, 1993
 *	The Regents of the University of California.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *	This product includes software developed by the University of
 *	California, Berkeley and its contributors.
 * 4. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#ifndef lint
#if 0
static char sccsid[] = "@(#)tftpsubs.c	8.1 (Berkeley) 6/6/93";
#endif
static const char rcsid[] =
  "$FreeBSD$";
#endif /* not lint */

/* Simple minded read-ahead/write-behind subroutines for tftp user and
   server.  Written originally with multiple buffers in mind, but current
   implementation has two buffer logic wired in.

   Todo:  add some sort of final error check so when the write-buffer
   is finally flushed, the caller can detect if the disk filled up
   (or had an i/o error) and return a nak to the other side.

			Jim Guyton 10/85
 */

#include <sys/types.h>
#include <sys/socket.h>
#include <sys/ioctl.h>
#include <netinet/in.h>
#include <arpa/tftp.h>

#include <stdio.h>
#include <unistd.h>

#include "tftpsubs.h"

#define PKTSIZE SEGSIZE+4       /* should be moved to tftp.h */

struct bf {
	int counter;            /* size of data in buffer, or flag */
	char buf[PKTSIZE];      /* room for data packet */
} bfs[2];

				/* Values for bf.counter  */
#define BF_ALLOC -3             /* alloc'd but not yet filled */
#define BF_FREE  -2             /* free */
/* [-1 .. SEGSIZE] = size of data in the data buffer */

static int nextone;		/* index of next buffer to use */
static int current;		/* index of buffer in use */

				/* control flags for crlf conversions */
int newline = 0;		/* fillbuf: in middle of newline expansion */
int prevchar = -1;		/* putbuf: previous char (cr check) */

static struct tftphdr *rw_init();

struct tftphdr *w_init() { return rw_init(0); }         /* write-behind */
struct tftphdr *r_init() { return rw_init(1); }         /* read-ahead */

static struct tftphdr *
rw_init(x)			/* init for either read-ahead or write-behind */
	int x;			/* zero for write-behind, one for read-head */
{
	newline = 0;		/* init crlf flag */
	prevchar = -1;
	bfs[0].counter =  BF_ALLOC;     /* pass out the first buffer */
	current = 0;
	bfs[1].counter = BF_FREE;
	nextone = x;                    /* ahead or behind? */
	return (struct tftphdr *)bfs[0].buf;
}


/* Have emptied current buffer by sending to net and getting ack.
   Free it and return next buffer filled with data.
 */
int
readit(file, dpp, convert)
	FILE *file;                     /* file opened for read */
	struct tftphdr **dpp;
	int convert;                    /* if true, convert to ascii */
{
	struct bf *b;

	bfs[current].counter = BF_FREE; /* free old one */
	current = !current;             /* "incr" current */

	b = &bfs[current];              /* look at new buffer */
	if (b->counter == BF_FREE)      /* if it's empty */
		read_ahead(file, convert);      /* fill it */
/*      assert(b->counter != BF_FREE);*//* check */
	*dpp = (struct tftphdr *)b->buf;        /* set caller's ptr */
	return b->counter;
}

/*
 * fill the input buffer, doing ascii conversions if requested
 * conversions are  lf -> cr,lf  and cr -> cr, nul
 */
void
read_ahead(file, convert)
	FILE *file;                     /* file opened for read */
	int convert;                    /* if true, convert to ascii */
{
	register int i;
	register char *p;
	register int c;
	struct bf *b;
	struct tftphdr *dp;

	b = &bfs[nextone];              /* look at "next" buffer */
	if (b->counter != BF_FREE)      /* nop if not free */
		return;
	nextone = !nextone;             /* "incr" next buffer ptr */

	dp = (struct tftphdr *)b->buf;

	if (convert == 0) {
		b->counter = read(fileno(file), dp->th_data, SEGSIZE);
		return;
	}

	p = dp->th_data;
	for (i = 0 ; i < SEGSIZE; i++) {
		if (newline) {
			if (prevchar == '\n')
				c = '\n';       /* lf to cr,lf */
			else    c = '\0';       /* cr to cr,nul */
			newline = 0;
		}
		else {
			c = getc(file);
			if (c == EOF) break;
			if (c == '\n' || c == '\r') {
				prevchar = c;
				c = '\r';
				newline = 1;
			}
		}
	       *p++ = c;
	}
	b->counter = (int)(p - dp->th_data);
}

/* Update count associated with the buffer, get new buffer
   from the queue.  Calls write_behind only if next buffer not
   available.
 */
int
writeit(file, dpp, ct, convert)
	FILE *file;
	struct tftphdr **dpp;
	int ct, convert;
{
	bfs[current].counter = ct;      /* set size of data to write */
	current = !current;             /* switch to other buffer */
	if (bfs[current].counter != BF_FREE)     /* if not free */
		(void)write_behind(file, convert); /* flush it */
	bfs[current].counter = BF_ALLOC;        /* mark as alloc'd */
	*dpp =  (struct tftphdr *)bfs[current].buf;
	return ct;                      /* this is a lie of course */
}

/*
 * Output a buffer to a file, converting from netascii if requested.
 * CR,NUL -> CR  and CR,LF => LF.
 * Note spec is undefined if we get CR as last byte of file or a
 * CR followed by anything else.  In this case we leave it alone.
 */
int
write_behind(file, convert)
	FILE *file;
	int convert;
{
	char *buf;
	int count;
	register int ct;
	register char *p;
	register int c;                 /* current character */
	struct bf *b;
	struct tftphdr *dp;

	b = &bfs[nextone];
	if (b->counter < -1)            /* anything to flush? */
		return 0;               /* just nop if nothing to do */

	count = b->counter;             /* remember byte count */
	b->counter = BF_FREE;           /* reset flag */
	dp = (struct tftphdr *)b->buf;
	nextone = !nextone;             /* incr for next time */
	buf = dp->th_data;

	if (count <= 0) return -1;      /* nak logic? */

	if (convert == 0)
		return write(fileno(file), buf, count);

	p = buf;
	ct = count;
	while (ct--) {                  /* loop over the buffer */
	    c = *p++;                   /* pick up a character */
	    if (prevchar == '\r') {     /* if prev char was cr */
		if (c == '\n')          /* if have cr,lf then just */
		   fseek(file, -1, 1);  /* smash lf on top of the cr */
		else
		   if (c == '\0')       /* if have cr,nul then */
			goto skipit;    /* just skip over the putc */
		/* else just fall through and allow it */
	    }
	    putc(c, file);
skipit:
	    prevchar = c;
	}
	return count;
}


/* When an error has occurred, it is possible that the two sides
 * are out of synch.  Ie: that what I think is the other side's
 * response to packet N is really their response to packet N-1.
 *
 * So, to try to prevent that, we flush all the input queued up
 * for us on the network connection on our host.
 *
 * We return the number of packets we flushed (mostly for reporting
 * when trace is active).
 */

int
synchnet(f)
	int	f;		/* socket to flush */
{
	int i, j = 0;
	char rbuf[PKTSIZE];
	struct sockaddr_in from;
	int fromlen;

	while (1) {
		(void) ioctl(f, FIONREAD, &i);
		if (i) {
			j++;
			fromlen = sizeof from;
			(void) recvfrom(f, rbuf, sizeof (rbuf), 0,
				(struct sockaddr *)&from, &fromlen);
		} else {
			return(j);
		}
	}
}
OpenPOWER on IntegriCloud