Annotation of src/usr.bin/tftp/tftpsubs.c, Revision 1.15
1.15 ! gsoares 1: /* $OpenBSD: tftpsubs.c,v 1.14 2009/10/27 23:59:44 deraadt 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:
1.10 mglocker 33: /*
34: * Simple minded read-ahead/write-behind subroutines for tftp user and
35: * server. Written originally with multiple buffers in mind, but current
36: * implementation has two buffer logic wired in.
37: *
38: * Todo: add some sort of final error check so when the write-buffer
39: * is finally flushed, the caller can detect if the disk filled up
40: * (or had an i/o error) and return a nak to the other side.
41: *
42: * Jim Guyton 10/85
1.1 deraadt 43: */
44:
45: #include <sys/types.h>
46: #include <sys/socket.h>
47: #include <sys/ioctl.h>
1.10 mglocker 48:
1.1 deraadt 49: #include <netinet/in.h>
50: #include <arpa/tftp.h>
51:
52: #include <stdio.h>
53: #include <unistd.h>
54:
55: #include "tftpsubs.h"
56:
1.10 mglocker 57: /* values for bf.counter */
58: #define BF_ALLOC -3 /* alloc'd but not yet filled */
59: #define BF_FREE -2 /* free */
60: /* [-1 .. SEGSIZE] = size of data in the data buffer */
61:
62: static struct tftphdr *rw_init(int);
1.1 deraadt 63:
64: struct bf {
1.11 mglocker 65: int counter; /* size of data in buffer, or flag */
66: char buf[SEGSIZE_MAX + 4]; /* room for data packet */
1.1 deraadt 67: } bfs[2];
68:
1.10 mglocker 69: static int nextone; /* index of next buffer to use */
70: static int current; /* index of buffer in use */
1.1 deraadt 71: /* control flags for crlf conversions */
1.10 mglocker 72: int newline = 0; /* fillbuf: in middle of newline expansion */
73: int prevchar = -1; /* putbuf: previous char (cr check) */
1.1 deraadt 74:
1.7 deraadt 75: struct tftphdr *
76: w_init(void)
77: {
1.10 mglocker 78: return (rw_init(0)); /* write-behind */
1.7 deraadt 79: }
80:
81: struct tftphdr *
82: r_init(void)
83: {
1.10 mglocker 84: return (rw_init(1)); /* read-ahead */
1.7 deraadt 85: }
1.1 deraadt 86:
1.10 mglocker 87: /*
88: * Init for either read-ahead or write-behind.
89: * Zero for write-behind, one for read-head.
90: */
1.1 deraadt 91: static struct tftphdr *
1.7 deraadt 92: rw_init(int x)
1.1 deraadt 93: {
1.10 mglocker 94: newline = 0; /* init crlf flag */
1.1 deraadt 95: prevchar = -1;
1.12 mglocker 96: bfs[0].counter = BF_ALLOC; /* pass out the first buffer */
1.1 deraadt 97: current = 0;
98: bfs[1].counter = BF_FREE;
1.10 mglocker 99: nextone = x; /* ahead or behind? */
100:
101: return ((struct tftphdr *)bfs[0].buf);
1.1 deraadt 102: }
103:
1.10 mglocker 104: /*
105: * Have emptied current buffer by sending to net and getting ack.
106: * Free it and return next buffer filled with data.
1.1 deraadt 107: */
108: int
1.11 mglocker 109: readit(FILE *file, struct tftphdr **dpp, int convert, int segment_size)
1.1 deraadt 110: {
1.10 mglocker 111: struct bf *b;
112:
113: bfs[current].counter = BF_FREE; /* free old one */
114: current = !current; /* "incr" current */
1.1 deraadt 115:
1.10 mglocker 116: b = &bfs[current]; /* look at new buffer */
117: if (b->counter == BF_FREE) /* if it's empty */
1.11 mglocker 118: read_ahead(file, convert, segment_size); /* fill it */
1.10 mglocker 119: /* assert(b->counter != BF_FREE); */ /* check */
120: *dpp = (struct tftphdr *)b->buf; /* set caller's ptr */
1.1 deraadt 121:
1.10 mglocker 122: return (b->counter);
1.1 deraadt 123: }
124:
125: /*
1.10 mglocker 126: * Fill the input buffer, doing ascii conversions if requested.
127: * Conversions are lf -> cr, lf and cr -> cr, nul.
1.1 deraadt 128: */
129: void
1.11 mglocker 130: read_ahead(FILE *file, int convert, int segment_size)
1.1 deraadt 131: {
1.10 mglocker 132: int i;
133: char *p;
134: int c;
135: struct bf *b;
136: struct tftphdr *dp;
1.1 deraadt 137:
1.10 mglocker 138: b = &bfs[nextone]; /* look at "next" buffer */
139: if (b->counter != BF_FREE) /* nop if not free */
1.1 deraadt 140: return;
1.10 mglocker 141: nextone = !nextone; /* "incr" next buffer ptr */
1.1 deraadt 142:
143: dp = (struct tftphdr *)b->buf;
144:
145: if (convert == 0) {
1.11 mglocker 146: b->counter = read(fileno(file), dp->th_data, segment_size);
1.1 deraadt 147: return;
148: }
149:
150: p = dp->th_data;
1.11 mglocker 151: for (i = 0; i < segment_size; i++) {
1.1 deraadt 152: if (newline) {
153: if (prevchar == '\n')
1.10 mglocker 154: c = '\n'; /* lf to cr, lf */
1.9 deraadt 155: else
1.10 mglocker 156: c = '\0'; /* cr to cr, nul */
1.1 deraadt 157: newline = 0;
1.9 deraadt 158: } else {
1.1 deraadt 159: c = getc(file);
1.10 mglocker 160: if (c == EOF)
161: break;
1.1 deraadt 162: if (c == '\n' || c == '\r') {
163: prevchar = c;
164: c = '\r';
165: newline = 1;
166: }
167: }
168: *p++ = c;
169: }
170: b->counter = (int)(p - dp->th_data);
171: }
172:
1.10 mglocker 173: /*
174: * Update count associated with the buffer, get new buffer
175: * from the queue. Calls write_behind only if next buffer not
176: * available.
1.1 deraadt 177: */
178: int
1.7 deraadt 179: writeit(FILE *file, struct tftphdr **dpp, int ct, int convert)
1.1 deraadt 180: {
1.10 mglocker 181: bfs[current].counter = ct; /* set size of data to write */
182: current = !current; /* switch to other buffer */
183: if (bfs[current].counter != BF_FREE) /* if not free */
184: /* flush it */
185: (void)write_behind(file, convert);
186: bfs[current].counter = BF_ALLOC; /* mark as alloc'd */
1.1 deraadt 187: *dpp = (struct tftphdr *)bfs[current].buf;
1.10 mglocker 188:
189: return (ct); /* this is a lie of course */
1.1 deraadt 190: }
191:
192: /*
193: * Output a buffer to a file, converting from netascii if requested.
1.10 mglocker 194: * CR, NUL -> CR and CR, LF -> LF.
1.1 deraadt 195: * Note spec is undefined if we get CR as last byte of file or a
196: * CR followed by anything else. In this case we leave it alone.
1.10 mglocker 197: */
1.1 deraadt 198: int
1.7 deraadt 199: write_behind(FILE *file, int convert)
1.1 deraadt 200: {
1.10 mglocker 201: char *buf;
202: int count;
203: int ct;
204: char *p;
205: int c; /* current character */
206: struct bf *b;
207: struct tftphdr *dp;
1.1 deraadt 208:
209: b = &bfs[nextone];
1.10 mglocker 210: if (b->counter < -1) /* anything to flush? */
211: return (0); /* just nop if nothing to do */
1.1 deraadt 212:
1.10 mglocker 213: count = b->counter; /* remember byte count */
214: b->counter = BF_FREE; /* reset flag */
1.1 deraadt 215: dp = (struct tftphdr *)b->buf;
1.10 mglocker 216: nextone = !nextone; /* incr for next time */
1.1 deraadt 217: buf = dp->th_data;
218:
1.10 mglocker 219: if (count <= 0) /* nak logic? */
220: return (-1);
1.1 deraadt 221:
222: if (convert == 0)
1.10 mglocker 223: return (write(fileno(file), buf, count));
1.1 deraadt 224:
225: p = buf;
226: ct = count;
1.10 mglocker 227: while (ct--) { /* loop over the buffer */
228: c = *p++; /* pick up a character */
229: if (prevchar == '\r') { /* if prev char was cr */
230: if (c == '\n') /* if have cr,lf then just */
231: /* smash lf on top of the cr */
1.13 tobias 232: fseek(file, -1, SEEK_CUR);
1.10 mglocker 233: else if (c == '\0') /* if have cr,nul then */
234: goto skipit; /* just skip over the putc */
235: /* FALLTHROUGH */
1.9 deraadt 236: }
237: putc(c, file);
1.1 deraadt 238: skipit:
1.9 deraadt 239: prevchar = c;
1.1 deraadt 240: }
1.10 mglocker 241:
242: return (count);
1.1 deraadt 243: }
244:
1.10 mglocker 245: /*
246: * When an error has occurred, it is possible that the two sides
1.1 deraadt 247: * are out of synch. Ie: that what I think is the other side's
248: * response to packet N is really their response to packet N-1.
249: *
250: * So, to try to prevent that, we flush all the input queued up
251: * for us on the network connection on our host.
252: *
253: * We return the number of packets we flushed (mostly for reporting
254: * when trace is active).
255: */
256: int
1.7 deraadt 257: synchnet(int f)
1.1 deraadt 258: {
1.10 mglocker 259: int i, j = 0;
1.11 mglocker 260: char rbuf[SEGSIZE_MIN];
1.15 ! gsoares 261: struct sockaddr_storage from;
1.10 mglocker 262: socklen_t fromlen;
1.1 deraadt 263:
1.10 mglocker 264: for (;;) {
265: (void)ioctl(f, FIONREAD, &i);
1.1 deraadt 266: if (i) {
267: j++;
1.10 mglocker 268: fromlen = sizeof(from);
269: (void)recvfrom(f, rbuf, sizeof(rbuf), 0,
1.9 deraadt 270: (struct sockaddr *)&from, &fromlen);
1.10 mglocker 271: } else
272: return (j);
1.1 deraadt 273: }
274: }
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