Initial revision

contrib/tftp/tftpsubs.c

@@ -0,0 +1,260 @@
+/*
+ * Copyright (c) 1983 Regents of the University of California.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms are permitted
+ * provided that the above copyright notice and this paragraph are
+ * duplicated in all such forms and that any documentation,
+ * advertising materials, and other materials related to such
+ * distribution and use acknowledge that the software was developed
+ * by the University of California, Berkeley.  The name of the
+ * University may not be used to endorse or promote products derived
+ * from this software without specific prior written permission.
+ * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
+ * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
+ * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
+ */
+
+#ifndef lint
+static char sccsid[] = "@(#)tftpsubs.c	5.4 (Berkeley) 6/29/88";
+#endif /* not lint */
+
+/* Simple minded read-ahead/write-behind subroutines for tftp user and
+   server.  Written originally with multiple buffers in mind, but current
+   implementation has two buffer logic wired in.
+
+   Todo:  add some sort of final error check so when the write-buffer
+   is finally flushed, the caller can detect if the disk filled up
+   (or had an i/o error) and return a nak to the other side.
+
+			Jim Guyton 10/85
+ */
+
+#include <errno.h>
+#include <sys/types.h>
+#include <sys/socket.h>
+#include <sys/ioctl.h>
+#include <netinet/in.h>
+#include <arpa/tftp.h>
+#include <stdio.h>
+
+#define PKTSIZE (1432+4) /* SEGSIZE+4 */      /* should be moved to tftp.h */
+
+struct bf {
+	int counter;            /* size of data in buffer, or flag */
+	char buf[PKTSIZE];      /* room for data packet */
+} bfs[2];
+
+				/* Values for bf.counter  */
+#define BF_ALLOC -3             /* alloc'd but not yet filled */
+#define BF_FREE  -2             /* free */
+/* [-1 .. SEGSIZE] = size of data in the data buffer */
+
+extern int segsize;
+
+static int nextone;     /* index of next buffer to use */
+static int current;     /* index of buffer in use */
+
+			/* control flags for crlf conversions */
+int newline = 0;        /* fillbuf: in middle of newline expansion */
+int prevchar = -1;      /* putbuf: previous char (cr check) */
+
+struct tftphdr *rw_init();
+
+struct tftphdr *w_init() { return rw_init(0); }         /* write-behind */
+struct tftphdr *r_init() { return rw_init(1); }         /* read-ahead */
+
+struct tftphdr *
+rw_init(x)              /* init for either read-ahead or write-behind */
+int x;                  /* zero for write-behind, one for read-head */
+{
+	newline = 0;            /* init crlf flag */
+	prevchar = -1;
+	bfs[0].counter =  BF_ALLOC;     /* pass out the first buffer */
+	current = 0;
+	bfs[1].counter = BF_FREE;
+	nextone = x;                    /* ahead or behind? */
+	return (struct tftphdr *)bfs[0].buf;
+}
+
+
+/* Have emptied current buffer by sending to net and getting ack.
+   Free it and return next buffer filled with data.
+ */
+readit(file, dpp, convert)
+	FILE *file;                     /* file opened for read */
+	struct tftphdr **dpp;
+	int convert;                    /* if true, convert to ascii */
+{
+	struct bf *b;
+
+	bfs[current].counter = BF_FREE; /* free old one */
+	current = !current;             /* "incr" current */
+
+	b = &bfs[current];              /* look at new buffer */
+	if (b->counter == BF_FREE)      /* if it's empty */
+		read_ahead(file, convert);      /* fill it */
+/*      assert(b->counter != BF_FREE);  /* check */
+	*dpp = (struct tftphdr *)b->buf;        /* set caller's ptr */
+	return b->counter;
+}
+
+/*
+ * fill the input buffer, doing ascii conversions if requested
+ * conversions are  lf -> cr,lf  and cr -> cr, nul
+ */
+read_ahead(file, convert)
+	FILE *file;                     /* file opened for read */
+	int convert;                    /* if true, convert to ascii */
+{
+	register int i;
+	register char *p;
+	register int c;
+	struct bf *b;
+	struct tftphdr *dp;
+
+	b = &bfs[nextone];              /* look at "next" buffer */
+	if (b->counter != BF_FREE)      /* nop if not free */
+		return;
+	nextone = !nextone;             /* "incr" next buffer ptr */
+
+	dp = (struct tftphdr *)b->buf;
+
+	if (convert == 0) {
+		int i;
+	  	b->counter = 0;
+		do {
+			i = read(fileno(file), dp->th_data + b->counter,
+				 segsize - b->counter);
+			if (i > 0)
+				b->counter += i;
+		} while (i != 0 && !(i < 0 && errno != EINTR) &&
+			 b->counter < segsize);
+		return;
+	}
+
+	p = dp->th_data;
+	for (i = 0 ; i < segsize; i++) {
+		if (newline) {
+			if (prevchar == '\n')
+				c = '\n';       /* lf to cr,lf */
+			else    c = '\0';       /* cr to cr,nul */
+			newline = 0;
+		}
+		else {
+			c = getc(file);
+			if (c == EOF) break;
+			if (c == '\n' || c == '\r') {
+				prevchar = c;
+				c = '\r';
+				newline = 1;
+			}
+		}
+	       *p++ = c;
+	}
+	b->counter = (int)(p - dp->th_data);
+}
+
+/* Update count associated with the buffer, get new buffer
+   from the queue.  Calls write_behind only if next buffer not
+   available.
+ */
+writeit(file, dpp, ct, convert)
+	FILE *file;
+	struct tftphdr **dpp;
+	int convert;
+{
+	bfs[current].counter = ct;      /* set size of data to write */
+	current = !current;             /* switch to other buffer */
+	if (bfs[current].counter != BF_FREE)     /* if not free */
+		write_behind(file, convert);     /* flush it */
+	bfs[current].counter = BF_ALLOC;        /* mark as alloc'd */
+	*dpp =  (struct tftphdr *)bfs[current].buf;
+	return ct;                      /* this is a lie of course */
+}
+
+/*
+ * Output a buffer to a file, converting from netascii if requested.
+ * CR,NUL -> CR  and CR,LF => LF.
+ * Note spec is undefined if we get CR as last byte of file or a
+ * CR followed by anything else.  In this case we leave it alone.
+ */
+write_behind(file, convert)
+	FILE *file;
+	int convert;
+{
+	char *buf;
+	int count;
+	register int ct;
+	register char *p;
+	register int c;                 /* current character */
+	struct bf *b;
+	struct tftphdr *dp;
+
+	b = &bfs[nextone];
+	if (b->counter < -1)            /* anything to flush? */
+		return 0;               /* just nop if nothing to do */
+
+	count = b->counter;             /* remember byte count */
+	b->counter = BF_FREE;           /* reset flag */
+	dp = (struct tftphdr *)b->buf;
+	nextone = !nextone;             /* incr for next time */
+	buf = dp->th_data;
+
+	if (count <= 0) return -1;      /* nak logic? */
+
+	if (convert == 0)
+		return write(fileno(file), buf, count);
+
+	p = buf;
+	ct = count;
+	while (ct--) {                  /* loop over the buffer */
+	    c = *p++;                   /* pick up a character */
+	    if (prevchar == '\r') {     /* if prev char was cr */
+		if (c == '\n')          /* if have cr,lf then just */
+		   fseek(file, -1, 1);  /* smash lf on top of the cr */
+		else
+		   if (c == '\0')       /* if have cr,nul then */
+			goto skipit;    /* just skip over the putc */
+		/* else just fall through and allow it */
+	    }
+	    putc(c, file);
+skipit:
+	    prevchar = c;
+	}
+	return count;
+}
+
+
+/* When an error has occurred, it is possible that the two sides
+ * are out of synch.  Ie: that what I think is the other side's
+ * response to packet N is really their response to packet N-1.
+ *
+ * So, to try to prevent that, we flush all the input queued up
+ * for us on the network connection on our host.
+ *
+ * We return the number of packets we flushed (mostly for reporting
+ * when trace is active).
+ */
+
+int
+synchnet(f)
+int	f;		/* socket to flush */
+{
+	int i, j = 0;
+	char rbuf[PKTSIZE];
+	struct sockaddr_in from;
+	int fromlen;
+
+	while (1) {
+		(void) ioctl(f, FIONREAD, &i);
+		if (i) {
+			j++;
+			fromlen = sizeof from;
+			(void) recvfrom(f, rbuf, sizeof (rbuf), 0,
+				(struct sockaddr *)&from, &fromlen);
+		} else {
+			return(j);
+		}
+	}
+}