Annotation of src/usr.bin/tftp/tftpsubs.c, Revision 1.12
1.12 ! mglocker 1: /* $OpenBSD: tftpsubs.c,v 1.11 2006/07/20 09:42:44 mglocker Exp $ */
1.1 deraadt 2: /* $NetBSD: tftpsubs.c,v 1.3 1994/12/08 09:51:31 jtc Exp $ */
3:
4: /*
5: * Copyright (c) 1983, 1993
6: * The Regents of the University of California. All rights reserved.
7: *
8: * Redistribution and use in source and binary forms, with or without
9: * modification, are permitted provided that the following conditions
10: * are met:
11: * 1. Redistributions of source code must retain the above copyright
12: * notice, this list of conditions and the following disclaimer.
13: * 2. Redistributions in binary form must reproduce the above copyright
14: * notice, this list of conditions and the following disclaimer in the
15: * documentation and/or other materials provided with the distribution.
1.6 millert 16: * 3. Neither the name of the University nor the names of its contributors
1.1 deraadt 17: * may be used to endorse or promote products derived from this software
18: * without specific prior written permission.
19: *
20: * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
21: * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
22: * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
23: * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
24: * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
25: * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
26: * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
27: * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
28: * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
29: * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
30: * SUCH DAMAGE.
31: */
32:
33: #ifndef lint
34: #if 0
35: static char sccsid[] = "@(#)tftpsubs.c 8.1 (Berkeley) 6/6/93";
36: #endif
1.10 mglocker 37: static const char rcsid[] =
1.12 ! mglocker 38: "$OpenBSD: tftpsubs.c,v 1.11 2006/07/20 09:42:44 mglocker Exp $";
1.1 deraadt 39: #endif /* not lint */
40:
1.10 mglocker 41: /*
42: * Simple minded read-ahead/write-behind subroutines for tftp user and
43: * server. Written originally with multiple buffers in mind, but current
44: * implementation has two buffer logic wired in.
45: *
46: * Todo: add some sort of final error check so when the write-buffer
47: * is finally flushed, the caller can detect if the disk filled up
48: * (or had an i/o error) and return a nak to the other side.
49: *
50: * Jim Guyton 10/85
1.1 deraadt 51: */
52:
53: #include <sys/types.h>
54: #include <sys/socket.h>
55: #include <sys/ioctl.h>
1.10 mglocker 56:
1.1 deraadt 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:
1.10 mglocker 65: /* values for bf.counter */
66: #define BF_ALLOC -3 /* alloc'd but not yet filled */
67: #define BF_FREE -2 /* free */
68: /* [-1 .. SEGSIZE] = size of data in the data buffer */
69:
70: static struct tftphdr *rw_init(int);
1.1 deraadt 71:
72: struct bf {
1.11 mglocker 73: int counter; /* size of data in buffer, or flag */
74: char buf[SEGSIZE_MAX + 4]; /* room for data packet */
1.1 deraadt 75: } bfs[2];
76:
1.10 mglocker 77: static int nextone; /* index of next buffer to use */
78: static int current; /* index of buffer in use */
1.1 deraadt 79: /* control flags for crlf conversions */
1.10 mglocker 80: int newline = 0; /* fillbuf: in middle of newline expansion */
81: int prevchar = -1; /* putbuf: previous char (cr check) */
1.1 deraadt 82:
1.7 deraadt 83: struct tftphdr *
84: w_init(void)
85: {
1.10 mglocker 86: return (rw_init(0)); /* write-behind */
1.7 deraadt 87: }
88:
89: struct tftphdr *
90: r_init(void)
91: {
1.10 mglocker 92: return (rw_init(1)); /* read-ahead */
1.7 deraadt 93: }
1.1 deraadt 94:
1.10 mglocker 95: /*
96: * Init for either read-ahead or write-behind.
97: * Zero for write-behind, one for read-head.
98: */
1.1 deraadt 99: static struct tftphdr *
1.7 deraadt 100: rw_init(int x)
1.1 deraadt 101: {
1.10 mglocker 102: newline = 0; /* init crlf flag */
1.1 deraadt 103: prevchar = -1;
1.12 ! mglocker 104: bfs[0].counter = BF_ALLOC; /* pass out the first buffer */
1.1 deraadt 105: current = 0;
106: bfs[1].counter = BF_FREE;
1.10 mglocker 107: nextone = x; /* ahead or behind? */
108:
109: return ((struct tftphdr *)bfs[0].buf);
1.1 deraadt 110: }
111:
1.10 mglocker 112: /*
113: * Have emptied current buffer by sending to net and getting ack.
114: * Free it and return next buffer filled with data.
1.1 deraadt 115: */
116: int
1.11 mglocker 117: readit(FILE *file, struct tftphdr **dpp, int convert, int segment_size)
1.1 deraadt 118: {
1.10 mglocker 119: struct bf *b;
120:
121: bfs[current].counter = BF_FREE; /* free old one */
122: current = !current; /* "incr" current */
1.1 deraadt 123:
1.10 mglocker 124: b = &bfs[current]; /* look at new buffer */
125: if (b->counter == BF_FREE) /* if it's empty */
1.11 mglocker 126: read_ahead(file, convert, segment_size); /* fill it */
1.10 mglocker 127: /* assert(b->counter != BF_FREE); */ /* check */
128: *dpp = (struct tftphdr *)b->buf; /* set caller's ptr */
1.1 deraadt 129:
1.10 mglocker 130: return (b->counter);
1.1 deraadt 131: }
132:
133: /*
1.10 mglocker 134: * Fill the input buffer, doing ascii conversions if requested.
135: * Conversions are lf -> cr, lf and cr -> cr, nul.
1.1 deraadt 136: */
137: void
1.11 mglocker 138: read_ahead(FILE *file, int convert, int segment_size)
1.1 deraadt 139: {
1.10 mglocker 140: int i;
141: char *p;
142: int c;
143: struct bf *b;
144: struct tftphdr *dp;
1.1 deraadt 145:
1.10 mglocker 146: b = &bfs[nextone]; /* look at "next" buffer */
147: if (b->counter != BF_FREE) /* nop if not free */
1.1 deraadt 148: return;
1.10 mglocker 149: nextone = !nextone; /* "incr" next buffer ptr */
1.1 deraadt 150:
151: dp = (struct tftphdr *)b->buf;
152:
153: if (convert == 0) {
1.11 mglocker 154: b->counter = read(fileno(file), dp->th_data, segment_size);
1.1 deraadt 155: return;
156: }
157:
158: p = dp->th_data;
1.11 mglocker 159: for (i = 0; i < segment_size; i++) {
1.1 deraadt 160: if (newline) {
161: if (prevchar == '\n')
1.10 mglocker 162: c = '\n'; /* lf to cr, lf */
1.9 deraadt 163: else
1.10 mglocker 164: c = '\0'; /* cr to cr, nul */
1.1 deraadt 165: newline = 0;
1.9 deraadt 166: } else {
1.1 deraadt 167: c = getc(file);
1.10 mglocker 168: if (c == EOF)
169: break;
1.1 deraadt 170: if (c == '\n' || c == '\r') {
171: prevchar = c;
172: c = '\r';
173: newline = 1;
174: }
175: }
176: *p++ = c;
177: }
178: b->counter = (int)(p - dp->th_data);
179: }
180:
1.10 mglocker 181: /*
182: * Update count associated with the buffer, get new buffer
183: * from the queue. Calls write_behind only if next buffer not
184: * available.
1.1 deraadt 185: */
186: int
1.7 deraadt 187: writeit(FILE *file, struct tftphdr **dpp, int ct, int convert)
1.1 deraadt 188: {
1.10 mglocker 189: bfs[current].counter = ct; /* set size of data to write */
190: current = !current; /* switch to other buffer */
191: if (bfs[current].counter != BF_FREE) /* if not free */
192: /* flush it */
193: (void)write_behind(file, convert);
194: bfs[current].counter = BF_ALLOC; /* mark as alloc'd */
1.1 deraadt 195: *dpp = (struct tftphdr *)bfs[current].buf;
1.10 mglocker 196:
197: return (ct); /* this is a lie of course */
1.1 deraadt 198: }
199:
200: /*
201: * Output a buffer to a file, converting from netascii if requested.
1.10 mglocker 202: * CR, NUL -> CR and CR, LF -> LF.
1.1 deraadt 203: * Note spec is undefined if we get CR as last byte of file or a
204: * CR followed by anything else. In this case we leave it alone.
1.10 mglocker 205: */
1.1 deraadt 206: int
1.7 deraadt 207: write_behind(FILE *file, int convert)
1.1 deraadt 208: {
1.10 mglocker 209: char *buf;
210: int count;
211: int ct;
212: char *p;
213: int c; /* current character */
214: struct bf *b;
215: struct tftphdr *dp;
1.1 deraadt 216:
217: b = &bfs[nextone];
1.10 mglocker 218: if (b->counter < -1) /* anything to flush? */
219: return (0); /* just nop if nothing to do */
1.1 deraadt 220:
1.10 mglocker 221: count = b->counter; /* remember byte count */
222: b->counter = BF_FREE; /* reset flag */
1.1 deraadt 223: dp = (struct tftphdr *)b->buf;
1.10 mglocker 224: nextone = !nextone; /* incr for next time */
1.1 deraadt 225: buf = dp->th_data;
226:
1.10 mglocker 227: if (count <= 0) /* nak logic? */
228: return (-1);
1.1 deraadt 229:
230: if (convert == 0)
1.10 mglocker 231: return (write(fileno(file), buf, count));
1.1 deraadt 232:
233: p = buf;
234: ct = count;
1.10 mglocker 235: while (ct--) { /* loop over the buffer */
236: c = *p++; /* pick up a character */
237: if (prevchar == '\r') { /* if prev char was cr */
238: if (c == '\n') /* if have cr,lf then just */
239: /* smash lf on top of the cr */
240: fseek(file, -1, 1);
241: else if (c == '\0') /* if have cr,nul then */
242: goto skipit; /* just skip over the putc */
243: /* FALLTHROUGH */
1.9 deraadt 244: }
245: putc(c, file);
1.1 deraadt 246: skipit:
1.9 deraadt 247: prevchar = c;
1.1 deraadt 248: }
1.10 mglocker 249:
250: return (count);
1.1 deraadt 251: }
252:
1.10 mglocker 253: /*
254: * When an error has occurred, it is possible that the two sides
1.1 deraadt 255: * are out of synch. Ie: that what I think is the other side's
256: * response to packet N is really their response to packet N-1.
257: *
258: * So, to try to prevent that, we flush all the input queued up
259: * for us on the network connection on our host.
260: *
261: * We return the number of packets we flushed (mostly for reporting
262: * when trace is active).
263: */
264: int
1.7 deraadt 265: synchnet(int f)
1.1 deraadt 266: {
1.10 mglocker 267: int i, j = 0;
1.11 mglocker 268: char rbuf[SEGSIZE_MIN];
1.10 mglocker 269: struct sockaddr_in from;
270: socklen_t fromlen;
1.1 deraadt 271:
1.10 mglocker 272: for (;;) {
273: (void)ioctl(f, FIONREAD, &i);
1.1 deraadt 274: if (i) {
275: j++;
1.10 mglocker 276: fromlen = sizeof(from);
277: (void)recvfrom(f, rbuf, sizeof(rbuf), 0,
1.9 deraadt 278: (struct sockaddr *)&from, &fromlen);
1.10 mglocker 279: } else
280: return (j);
1.1 deraadt 281: }
282: }
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