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1.1 root 1: /*
2: * Copyright (c) 1983 Regents of the University of California.
3: * All rights reserved.
4: *
5: * Redistribution and use in source and binary forms are permitted
6: * provided that the above copyright notice and this paragraph are
7: * duplicated in all such forms and that any documentation,
8: * advertising materials, and other materials related to such
9: * distribution and use acknowledge that the software was developed
10: * by the University of California, Berkeley. The name of the
11: * University may not be used to endorse or promote products derived
12: * from this software without specific prior written permission.
13: * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
14: * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
15: * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
16: */
17:
18: #ifndef lint
19: static char sccsid[] = "@(#)tftpsubs.c 5.4 (Berkeley) 6/29/88";
20: #endif /* not lint */
21:
22: /* Simple minded read-ahead/write-behind subroutines for tftp user and
23: server. Written originally with multiple buffers in mind, but current
24: implementation has two buffer logic wired in.
25:
26: Todo: add some sort of final error check so when the write-buffer
27: is finally flushed, the caller can detect if the disk filled up
28: (or had an i/o error) and return a nak to the other side.
29:
30: Jim Guyton 10/85
31: */
32:
33: #include <sys/types.h>
34: #include <sys/socket.h>
35: #include <sys/ioctl.h>
36: #include <netinet/in.h>
37: #include <arpa/tftp.h>
38: #include <stdio.h>
39:
40: #define PKTSIZE SEGSIZE+4 /* should be moved to tftp.h */
41:
42: struct bf {
43: int counter; /* size of data in buffer, or flag */
44: char buf[PKTSIZE]; /* room for data packet */
45: } bfs[2];
46:
47: /* Values for bf.counter */
48: #define BF_ALLOC -3 /* alloc'd but not yet filled */
49: #define BF_FREE -2 /* free */
50: /* [-1 .. SEGSIZE] = size of data in the data buffer */
51:
52: static int nextone; /* index of next buffer to use */
53: static int current; /* index of buffer in use */
54:
55: /* control flags for crlf conversions */
56: int newline = 0; /* fillbuf: in middle of newline expansion */
57: int prevchar = -1; /* putbuf: previous char (cr check) */
58:
59: struct tftphdr *rw_init();
60:
61: struct tftphdr *w_init() { return rw_init(0); } /* write-behind */
62: struct tftphdr *r_init() { return rw_init(1); } /* read-ahead */
63:
64: struct tftphdr *
65: rw_init(x) /* init for either read-ahead or write-behind */
66: int x; /* zero for write-behind, one for read-head */
67: {
68: newline = 0; /* init crlf flag */
69: prevchar = -1;
70: bfs[0].counter = BF_ALLOC; /* pass out the first buffer */
71: current = 0;
72: bfs[1].counter = BF_FREE;
73: nextone = x; /* ahead or behind? */
74: return (struct tftphdr *)bfs[0].buf;
75: }
76:
77:
78: /* Have emptied current buffer by sending to net and getting ack.
79: Free it and return next buffer filled with data.
80: */
81: readit(file, dpp, convert)
82: FILE *file; /* file opened for read */
83: struct tftphdr **dpp;
84: int convert; /* if true, convert to ascii */
85: {
86: struct bf *b;
87:
88: bfs[current].counter = BF_FREE; /* free old one */
89: current = !current; /* "incr" current */
90:
91: b = &bfs[current]; /* look at new buffer */
92: if (b->counter == BF_FREE) /* if it's empty */
93: read_ahead(file, convert); /* fill it */
94: /* assert(b->counter != BF_FREE); /* check */
95: *dpp = (struct tftphdr *)b->buf; /* set caller's ptr */
96: return b->counter;
97: }
98:
99: /*
100: * fill the input buffer, doing ascii conversions if requested
101: * conversions are lf -> cr,lf and cr -> cr, nul
102: */
103: read_ahead(file, convert)
104: FILE *file; /* file opened for read */
105: int convert; /* if true, convert to ascii */
106: {
107: register int i;
108: register char *p;
109: register int c;
110: struct bf *b;
111: struct tftphdr *dp;
112:
113: b = &bfs[nextone]; /* look at "next" buffer */
114: if (b->counter != BF_FREE) /* nop if not free */
115: return;
116: nextone = !nextone; /* "incr" next buffer ptr */
117:
118: dp = (struct tftphdr *)b->buf;
119:
120: if (convert == 0) {
121: b->counter = read(fileno(file), dp->th_data, SEGSIZE);
122: return;
123: }
124:
125: p = dp->th_data;
126: for (i = 0 ; i < SEGSIZE; i++) {
127: if (newline) {
128: if (prevchar == '\n')
129: c = '\n'; /* lf to cr,lf */
130: else c = '\0'; /* cr to cr,nul */
131: newline = 0;
132: }
133: else {
134: c = getc(file);
135: if (c == EOF) break;
136: if (c == '\n' || c == '\r') {
137: prevchar = c;
138: c = '\r';
139: newline = 1;
140: }
141: }
142: *p++ = c;
143: }
144: b->counter = (int)(p - dp->th_data);
145: }
146:
147: /* Update count associated with the buffer, get new buffer
148: from the queue. Calls write_behind only if next buffer not
149: available.
150: */
151: writeit(file, dpp, ct, convert)
152: FILE *file;
153: struct tftphdr **dpp;
154: int convert;
155: {
156: bfs[current].counter = ct; /* set size of data to write */
157: current = !current; /* switch to other buffer */
158: if (bfs[current].counter != BF_FREE) /* if not free */
159: write_behind(file, convert); /* flush it */
160: bfs[current].counter = BF_ALLOC; /* mark as alloc'd */
161: *dpp = (struct tftphdr *)bfs[current].buf;
162: return ct; /* this is a lie of course */
163: }
164:
165: /*
166: * Output a buffer to a file, converting from netascii if requested.
167: * CR,NUL -> CR and CR,LF => LF.
168: * Note spec is undefined if we get CR as last byte of file or a
169: * CR followed by anything else. In this case we leave it alone.
170: */
171: write_behind(file, convert)
172: FILE *file;
173: int convert;
174: {
175: char *buf;
176: int count;
177: register int ct;
178: register char *p;
179: register int c; /* current character */
180: struct bf *b;
181: struct tftphdr *dp;
182:
183: b = &bfs[nextone];
184: if (b->counter < -1) /* anything to flush? */
185: return 0; /* just nop if nothing to do */
186:
187: count = b->counter; /* remember byte count */
188: b->counter = BF_FREE; /* reset flag */
189: dp = (struct tftphdr *)b->buf;
190: nextone = !nextone; /* incr for next time */
191: buf = dp->th_data;
192:
193: if (count <= 0) return -1; /* nak logic? */
194:
195: if (convert == 0)
196: return write(fileno(file), buf, count);
197:
198: p = buf;
199: ct = count;
200: while (ct--) { /* loop over the buffer */
201: c = *p++; /* pick up a character */
202: if (prevchar == '\r') { /* if prev char was cr */
203: if (c == '\n') /* if have cr,lf then just */
204: fseek(file, -1, 1); /* smash lf on top of the cr */
205: else
206: if (c == '\0') /* if have cr,nul then */
207: goto skipit; /* just skip over the putc */
208: /* else just fall through and allow it */
209: }
210: putc(c, file);
211: skipit:
212: prevchar = c;
213: }
214: return count;
215: }
216:
217:
218: /* When an error has occurred, it is possible that the two sides
219: * are out of synch. Ie: that what I think is the other side's
220: * response to packet N is really their response to packet N-1.
221: *
222: * So, to try to prevent that, we flush all the input queued up
223: * for us on the network connection on our host.
224: *
225: * We return the number of packets we flushed (mostly for reporting
226: * when trace is active).
227: */
228:
229: int
230: synchnet(f)
231: int f; /* socket to flush */
232: {
233: int i, j = 0;
234: char rbuf[PKTSIZE];
235: struct sockaddr_in from;
236: int fromlen;
237:
238: while (1) {
239: (void) ioctl(f, FIONREAD, &i);
240: if (i) {
241: j++;
242: fromlen = sizeof from;
243: (void) recvfrom(f, rbuf, sizeof (rbuf), 0,
244: (caddr_t)&from, &fromlen);
245: } else {
246: return(j);
247: }
248: }
249: }
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