2 * Copyright (c) 1983, 1993
3 * The Regents of the University of California. All rights reserved.
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15 * This product includes software developed by the University of
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33 * @(#)tftpsubs.c 8.1 (Berkeley) 6/6/93
34 * $FreeBSD: src/usr.bin/tftp/tftpsubs.c,v 1.3.2.1 2002/04/26 17:22:43 ume Exp $
35 * $DragonFly: src/usr.bin/tftp/tftpsubs.c,v 1.2 2003/06/17 04:29:32 dillon Exp $
38 /* Simple minded read-ahead/write-behind subroutines for tftp user and
39 server. Written originally with multiple buffers in mind, but current
40 implementation has two buffer logic wired in.
42 Todo: add some sort of final error check so when the write-buffer
43 is finally flushed, the caller can detect if the disk filled up
44 (or had an i/o error) and return a nak to the other side.
49 #include <sys/types.h>
50 #include <sys/socket.h>
51 #include <sys/ioctl.h>
52 #include <netinet/in.h>
53 #include <arpa/tftp.h>
60 #define PKTSIZE SEGSIZE+4 /* should be moved to tftp.h */
63 int counter; /* size of data in buffer, or flag */
64 char buf[PKTSIZE]; /* room for data packet */
67 /* Values for bf.counter */
68 #define BF_ALLOC -3 /* alloc'd but not yet filled */
69 #define BF_FREE -2 /* free */
70 /* [-1 .. SEGSIZE] = size of data in the data buffer */
72 static int nextone; /* index of next buffer to use */
73 static int current; /* index of buffer in use */
75 /* control flags for crlf conversions */
76 int newline = 0; /* fillbuf: in middle of newline expansion */
77 int prevchar = -1; /* putbuf: previous char (cr check) */
79 static struct tftphdr *rw_init();
81 struct tftphdr *w_init() { return rw_init(0); } /* write-behind */
82 struct tftphdr *r_init() { return rw_init(1); } /* read-ahead */
84 static struct tftphdr *
85 rw_init(x) /* init for either read-ahead or write-behind */
86 int x; /* zero for write-behind, one for read-head */
88 newline = 0; /* init crlf flag */
90 bfs[0].counter = BF_ALLOC; /* pass out the first buffer */
92 bfs[1].counter = BF_FREE;
93 nextone = x; /* ahead or behind? */
94 return (struct tftphdr *)bfs[0].buf;
98 /* Have emptied current buffer by sending to net and getting ack.
99 Free it and return next buffer filled with data.
102 readit(file, dpp, convert)
103 FILE *file; /* file opened for read */
104 struct tftphdr **dpp;
105 int convert; /* if true, convert to ascii */
109 bfs[current].counter = BF_FREE; /* free old one */
110 current = !current; /* "incr" current */
112 b = &bfs[current]; /* look at new buffer */
113 if (b->counter == BF_FREE) /* if it's empty */
114 read_ahead(file, convert); /* fill it */
115 /* assert(b->counter != BF_FREE);*//* check */
116 *dpp = (struct tftphdr *)b->buf; /* set caller's ptr */
121 * fill the input buffer, doing ascii conversions if requested
122 * conversions are lf -> cr,lf and cr -> cr, nul
125 read_ahead(file, convert)
126 FILE *file; /* file opened for read */
127 int convert; /* if true, convert to ascii */
135 b = &bfs[nextone]; /* look at "next" buffer */
136 if (b->counter != BF_FREE) /* nop if not free */
138 nextone = !nextone; /* "incr" next buffer ptr */
140 dp = (struct tftphdr *)b->buf;
143 b->counter = read(fileno(file), dp->th_data, SEGSIZE);
148 for (i = 0 ; i < SEGSIZE; i++) {
150 if (prevchar == '\n')
151 c = '\n'; /* lf to cr,lf */
152 else c = '\0'; /* cr to cr,nul */
158 if (c == '\n' || c == '\r') {
166 b->counter = (int)(p - dp->th_data);
169 /* Update count associated with the buffer, get new buffer
170 from the queue. Calls write_behind only if next buffer not
174 writeit(file, dpp, ct, convert)
176 struct tftphdr **dpp;
179 bfs[current].counter = ct; /* set size of data to write */
180 current = !current; /* switch to other buffer */
181 if (bfs[current].counter != BF_FREE) /* if not free */
182 (void)write_behind(file, convert); /* flush it */
183 bfs[current].counter = BF_ALLOC; /* mark as alloc'd */
184 *dpp = (struct tftphdr *)bfs[current].buf;
185 return ct; /* this is a lie of course */
189 * Output a buffer to a file, converting from netascii if requested.
190 * CR,NUL -> CR and CR,LF => LF.
191 * Note spec is undefined if we get CR as last byte of file or a
192 * CR followed by anything else. In this case we leave it alone.
195 write_behind(file, convert)
203 register int c; /* current character */
208 if (b->counter < -1) /* anything to flush? */
209 return 0; /* just nop if nothing to do */
211 count = b->counter; /* remember byte count */
212 b->counter = BF_FREE; /* reset flag */
213 dp = (struct tftphdr *)b->buf;
214 nextone = !nextone; /* incr for next time */
217 if (count <= 0) return -1; /* nak logic? */
220 return write(fileno(file), buf, count);
224 while (ct--) { /* loop over the buffer */
225 c = *p++; /* pick up a character */
226 if (prevchar == '\r') { /* if prev char was cr */
227 if (c == '\n') /* if have cr,lf then just */
228 fseek(file, -1, 1); /* smash lf on top of the cr */
230 if (c == '\0') /* if have cr,nul then */
231 goto skipit; /* just skip over the putc */
232 /* else just fall through and allow it */
242 /* When an error has occurred, it is possible that the two sides
243 * are out of synch. Ie: that what I think is the other side's
244 * response to packet N is really their response to packet N-1.
246 * So, to try to prevent that, we flush all the input queued up
247 * for us on the network connection on our host.
249 * We return the number of packets we flushed (mostly for reporting
250 * when trace is active).
255 int f; /* socket to flush */
259 struct sockaddr_storage from;
263 (void) ioctl(f, FIONREAD, &i);
266 fromlen = sizeof from;
267 (void) recvfrom(f, rbuf, sizeof (rbuf), 0,
268 (struct sockaddr *)&from, &fromlen);