1 /* $NetBSD: tftpsubs.c,v 1.12 2011/09/17 15:15:46 christos Exp $ */
2
3 /*
4 * Copyright (c) 1983, 1993
5 * The Regents of the University of California. All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution.
15 * 3. Neither the name of the University nor the names of its contributors
16 * may be used to endorse or promote products derived from this software
17 * without specific prior written permission.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29 * SUCH DAMAGE.
30 */
31
32 #include <sys/cdefs.h>
33 #ifndef lint
34 #if 0
35 static char sccsid[] = "@(#)tftpsubs.c 8.1 (Berkeley) 6/6/93";
36 #else
37 __RCSID("$NetBSD: tftpsubs.c,v 1.12 2011/09/17 15:15:46 christos Exp $");
38 #endif
39 #endif /* not lint */
40
41 /* Simple minded read-ahead/write-behind subroutines for tftp user and
42 server. Written originally with multiple buffers in mind, but current
43 implementation has two buffer logic wired in.
44
45 Todo: add some sort of final error check so when the write-buffer
46 is finally flushed, the caller can detect if the disk filled up
47 (or had an i/o error) and return a nak to the other side.
48
49 Jim Guyton 10/85
50 */
51
52 #include <sys/types.h>
53 #include <sys/socket.h>
54 #include <sys/ioctl.h>
55 #include <netinet/in.h>
56 #include <arpa/tftp.h>
57
58 #include <stdio.h>
59 #include <unistd.h>
60
61 #include "tftpsubs.h"
62
63 static struct bf {
64 int counter; /* size of data in buffer, or flag */
65 char buf[MAXPKTSIZE]; /* room for data packet */
66 } bfs[2];
67
68 /* Values for bf.counter */
69 #define BF_ALLOC -3 /* alloc'd but not yet filled */
70 #define BF_FREE -2 /* free */
71 /* [-1 .. SEGSIZE] = size of data in the data buffer */
72
73 static int nextone; /* index of next buffer to use */
74 static int current; /* index of buffer in use */
75
76 /* control flags for crlf conversions */
77 static int newline = 0; /* fillbuf: in middle of newline expansion */
78 static int prevchar = -1; /* putbuf: previous char (cr check) */
79
80 static struct tftphdr *rw_init(int);
81
82 struct tftphdr *
w_init(void)83 w_init(void) /* write-behind */
84 {
85 return rw_init(0);
86 }
87
88 struct tftphdr *
r_init(void)89 r_init(void) /* read-ahead */
90 {
91 return rw_init(1);
92 }
93
94 static struct tftphdr *
rw_init(int x)95 rw_init(int x) /* init for either read-ahead or write-behind */
96 /* zero for write-behind, one for read-head */
97 {
98 newline = 0; /* init crlf flag */
99 prevchar = -1;
100 bfs[0].counter = BF_ALLOC; /* pass out the first buffer */
101 current = 0;
102 bfs[1].counter = BF_FREE;
103 nextone = x; /* ahead or behind? */
104 return (struct tftphdr *)(void *)bfs[0].buf;
105 }
106
107 /* Have emptied current buffer by sending to net and getting ack.
108 Free it and return next buffer filled with data.
109 */
110 int
readit(FILE * file,struct tftphdr ** dpp,size_t amt,int convert)111 readit(
112 FILE *file, /* file opened for read */
113 struct tftphdr **dpp,
114 size_t amt,
115 int convert) /* if true, convert to ascii */
116 {
117 struct bf *b;
118
119 bfs[current].counter = BF_FREE; /* free old one */
120 current = !current; /* "incr" current */
121
122 b = &bfs[current]; /* look at new buffer */
123 if (b->counter == BF_FREE) /* if it's empty */
124 read_ahead(file, amt, convert); /* fill it */
125 /* assert(b->counter != BF_FREE);*//* check */
126 *dpp = (struct tftphdr *)(void *)b->buf; /* set caller's ptr */
127 return b->counter;
128 }
129
130 /*
131 * fill the input buffer, doing ascii conversions if requested
132 * conversions are lf -> cr,lf and cr -> cr, nul
133 */
134 void
read_ahead(FILE * file,size_t amt,int convert)135 read_ahead(
136 FILE *file, /* file opened for read */
137 size_t amt, /* number of bytes to read */
138 int convert) /* if true, convert to ascii */
139 {
140 size_t i;
141 char *p;
142 int c;
143 struct bf *b;
144 struct tftphdr *dp;
145
146 b = &bfs[nextone]; /* look at "next" buffer */
147 if (b->counter != BF_FREE) /* nop if not free */
148 return;
149 nextone = !nextone; /* "incr" next buffer ptr */
150
151 dp = (struct tftphdr *)(void *)b->buf;
152
153 if (convert == 0) {
154 b->counter = read(fileno(file), dp->th_data, amt);
155 return;
156 }
157
158 p = dp->th_data;
159 for (i = 0 ; i < amt; i++) {
160 if (newline) {
161 if (prevchar == '\n')
162 c = '\n'; /* lf to cr,lf */
163 else c = '\0'; /* cr to cr,nul */
164 newline = 0;
165 }
166 else {
167 c = getc(file);
168 if (c == EOF) break;
169 if (c == '\n' || c == '\r') {
170 prevchar = c;
171 c = '\r';
172 newline = 1;
173 }
174 }
175 *p++ = c;
176 }
177 b->counter = (int)(p - dp->th_data);
178 }
179
180 /* Update count associated with the buffer, get new buffer
181 from the queue. Calls write_behind only if next buffer not
182 available.
183 */
184 int
writeit(FILE * file,struct tftphdr ** dpp,int ct,int convert)185 writeit(FILE *file, struct tftphdr **dpp, int ct, int convert)
186 {
187 bfs[current].counter = ct; /* set size of data to write */
188 current = !current; /* switch to other buffer */
189 if (bfs[current].counter != BF_FREE) /* if not free */
190 if (write_behind(file, convert) == -1) /* flush it */
191 return -1;
192 bfs[current].counter = BF_ALLOC; /* mark as alloc'd */
193 *dpp = (struct tftphdr *)(void *)bfs[current].buf;
194 return ct; /* this is a lie of course */
195 }
196
197 /*
198 * Output a buffer to a file, converting from netascii if requested.
199 * CR,NUL -> CR and CR,LF => LF.
200 * Note spec is undefined if we get CR as last byte of file or a
201 * CR followed by anything else. In this case we leave it alone.
202 */
203 int
write_behind(FILE * file,int convert)204 write_behind(FILE *file, int convert)
205 {
206 char *buf;
207 int count;
208 int ct;
209 char *p;
210 int c; /* current character */
211 struct bf *b;
212 struct tftphdr *dp;
213
214 b = &bfs[nextone];
215 if (b->counter < -1) /* anything to flush? */
216 return 0; /* just nop if nothing to do */
217
218 count = b->counter; /* remember byte count */
219 b->counter = BF_FREE; /* reset flag */
220 dp = (struct tftphdr *)(void *)b->buf;
221 nextone = !nextone; /* incr for next time */
222 buf = dp->th_data;
223
224 if (count <= 0) return -1; /* nak logic? */
225
226 if (convert == 0)
227 return write(fileno(file), buf, (size_t)count);
228
229 p = buf;
230 ct = count;
231 while (ct--) { /* loop over the buffer */
232 c = *p++; /* pick up a character */
233 if (prevchar == '\r') { /* if prev char was cr */
234 if (c == '\n') /* if have cr,lf then just */
235 (void)fseeko(file, (off_t)-1, 1); /* smash lf on top of the cr */
236 else
237 if (c == '\0') /* if have cr,nul then */
238 goto skipit; /* just skip over the putc */
239 /* else just fall through and allow it */
240 }
241 if (putc(c, file) == EOF)
242 return -1;
243 skipit:
244 prevchar = c;
245 }
246 return count;
247 }
248
249
250 /* When an error has occurred, it is possible that the two sides
251 * are out of synch. Ie: that what I think is the other side's
252 * response to packet N is really their response to packet N-1.
253 *
254 * So, to try to prevent that, we flush all the input queued up
255 * for us on the network connection on our host.
256 *
257 * We return the number of packets we flushed (mostly for reporting
258 * when trace is active).
259 */
260
261 int
262 /*ARGSUSED*/
synchnet(int f,size_t bsize)263 synchnet(
264 int f, /* socket to flush */
265 size_t bsize) /* size of buffer to sync */
266 {
267 int i, j = 0;
268 char rbuf[PKTSIZE];
269 struct sockaddr_storage from;
270 socklen_t fromlen;
271
272 for (;;) {
273 (void) ioctl(f, FIONREAD, &i);
274 if (i) {
275 j++;
276 fromlen = sizeof from;
277 (void)recvfrom(f, rbuf, sizeof (rbuf), 0,
278 (struct sockaddr *)(void *)&from, &fromlen);
279 } else {
280 return j;
281 }
282 }
283 }
284