1 /* @(#)xdr_rec.c 2.2 88/08/01 4.0 RPCSRC */
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30 #if !defined(lint) && defined(SCCSIDS)
31 static char sccsid
[] = "@(#)xdr_rec.c 1.21 87/08/11 Copyr 1984 Sun Micro";
35 * xdr_rec.c, Implements TCP/IP based XDR streams with a "record marking"
36 * layer above tcp (for rpc's use).
38 * Copyright (C) 1984, Sun Microsystems, Inc.
40 * These routines interface XDRSTREAMS to a tcp/ip connection.
41 * There is a record marking layer between the xdr stream
42 * and the tcp transport level. A record is composed on one or more
43 * record fragments. A record fragment is a thirty-two bit header followed
44 * by n bytes of data, where n is contained in the header. The header
45 * is represented as a htonl(u_long). The high order bit encodes
46 * whether or not the fragment is the last fragment of the record
47 * (1 => fragment is last, 0 => more fragments to follow.
48 * The other 31 bits encode the byte length of the fragment.
56 static bool_t
xdrrec_getlong (XDR
*, long *);
57 static bool_t
xdrrec_putlong (XDR
*, const long *);
58 static bool_t
xdrrec_getbytes (XDR
*, caddr_t
, u_int
);
59 static bool_t
xdrrec_putbytes (XDR
*, const char *, u_int
);
60 static u_int
xdrrec_getpos (const XDR
*);
61 static bool_t
xdrrec_setpos (XDR
*, u_int
);
62 static long *xdrrec_inline (XDR
*, int);
63 static void xdrrec_destroy (XDR
*);
65 static const struct xdr_ops xdrrec_ops
=
78 * A record is composed of one or more record fragments.
79 * A record fragment is a two-byte header followed by zero to
80 * 2**32-1 bytes. The header is treated as a long unsigned and is
81 * encode/decoded to the network via htonl/ntohl. The low order 31 bits
82 * are a byte count of the fragment. The highest order bit is a boolean:
83 * 1 => this fragment is the last fragment of the record,
84 * 0 => this fragment is followed by more fragment(s).
86 * The fragment/record machinery is not general; it is constructed to
87 * meet the needs of xdr and rpc based on tcp.
90 #define LAST_FRAG (1UL << 31)
92 typedef struct rec_strm
99 int (*writeit
) (char *, char *, int);
100 caddr_t out_base
; /* output buffer (points to frag header) */
101 caddr_t out_finger
; /* next output position */
102 caddr_t out_boundry
; /* data cannot up to this address */
103 u_int32_t
*frag_header
; /* beginning of curren fragment */
104 bool_t frag_sent
; /* true if buffer sent in middle of record */
108 int (*readit
) (char *, char *, int);
109 u_long in_size
; /* fixed size of the input buffer */
111 caddr_t in_finger
; /* location of next byte to be had */
112 caddr_t in_boundry
; /* can read up to this location */
113 long fbtbc
; /* fragment bytes to be consumed */
120 static u_int
fix_buf_size (u_int
) internal_function
;
121 static bool_t
skip_input_bytes (RECSTREAM
*, long) internal_function
;
122 static bool_t
flush_out (RECSTREAM
*, bool_t
) internal_function
;
123 static bool_t
set_input_fragment (RECSTREAM
*) internal_function
;
124 static bool_t
get_input_bytes (RECSTREAM
*, caddr_t
, int) internal_function
;
127 * Create an xdr handle for xdrrec
128 * xdrrec_create fills in xdrs. Sendsize and recvsize are
129 * send and recv buffer sizes (0 => use default).
130 * tcp_handle is an opaque handle that is passed as the first parameter to
131 * the procedures readit and writeit. Readit and writeit are read and
132 * write respectively. They are like the system
133 * calls expect that they take an opaque handle rather than an fd.
136 xdrrec_create (XDR
*xdrs
, u_int sendsize
,
137 u_int recvsize
, caddr_t tcp_handle
,
138 int (*readit
) (char *, char *, int),
139 int (*writeit
) (char *, char *, int))
141 RECSTREAM
*rstrm
= (RECSTREAM
*) mem_alloc (sizeof (RECSTREAM
));
146 (void) fputs (_("xdrrec_create: out of memory\n"), stderr
);
148 * This is bad. Should rework xdrrec_create to
149 * return a handle, and in this case return NULL
154 * adjust sizes and allocate buffer quad byte aligned
156 rstrm
->sendsize
= sendsize
= fix_buf_size (sendsize
);
157 rstrm
->recvsize
= recvsize
= fix_buf_size (recvsize
);
158 rstrm
->the_buffer
= mem_alloc (sendsize
+ recvsize
+ BYTES_PER_XDR_UNIT
);
159 if (rstrm
->the_buffer
== NULL
)
161 (void) fputs (_("xdrrec_create: out of memory\n"), stderr
);
164 tmp
= rstrm
->the_buffer
;
165 if ((size_t)tmp
% BYTES_PER_XDR_UNIT
)
166 tmp
+= BYTES_PER_XDR_UNIT
- (size_t)tmp
% BYTES_PER_XDR_UNIT
;
167 rstrm
->out_base
= tmp
;
168 rstrm
->in_base
= tmp
+ sendsize
;
172 /* We have to add the const since the `struct xdr_ops' in `struct XDR'
174 xdrs
->x_ops
= (struct xdr_ops
*) &xdrrec_ops
;
175 xdrs
->x_private
= (caddr_t
) rstrm
;
176 rstrm
->tcp_handle
= tcp_handle
;
177 rstrm
->readit
= readit
;
178 rstrm
->writeit
= writeit
;
179 rstrm
->out_finger
= rstrm
->out_boundry
= rstrm
->out_base
;
180 rstrm
->frag_header
= (u_int32_t
*) rstrm
->out_base
;
181 rstrm
->out_finger
+= 4;
182 rstrm
->out_boundry
+= sendsize
;
183 rstrm
->frag_sent
= FALSE
;
184 rstrm
->in_size
= recvsize
;
185 rstrm
->in_boundry
= rstrm
->in_base
;
186 rstrm
->in_finger
= (rstrm
->in_boundry
+= recvsize
);
188 rstrm
->last_frag
= TRUE
;
193 * The routines defined below are the xdr ops which will go into the
194 * xdr handle filled in by xdrrec_create.
198 xdrrec_getlong (xdrs
, lp
)
202 RECSTREAM
*rstrm
= (RECSTREAM
*) xdrs
->x_private
;
203 int32_t *buflp
= (int32_t *) rstrm
->in_finger
;
206 /* first try the inline, fast case */
207 if (rstrm
->fbtbc
>= BYTES_PER_XDR_UNIT
&&
208 rstrm
->in_boundry
- (char *) buflp
>= BYTES_PER_XDR_UNIT
)
210 *lp
= (int32_t) ntohl (*buflp
);
211 rstrm
->fbtbc
-= BYTES_PER_XDR_UNIT
;
212 rstrm
->in_finger
+= BYTES_PER_XDR_UNIT
;
216 if (!xdrrec_getbytes (xdrs
, (caddr_t
) & mylong
,
219 *lp
= (int32_t) ntohl (mylong
);
225 xdrrec_putlong (xdrs
, lp
)
229 RECSTREAM
*rstrm
= (RECSTREAM
*) xdrs
->x_private
;
230 int32_t *dest_lp
= (int32_t *) rstrm
->out_finger
;
232 if ((rstrm
->out_finger
+= BYTES_PER_XDR_UNIT
) > rstrm
->out_boundry
)
235 * this case should almost never happen so the code is
238 rstrm
->out_finger
-= BYTES_PER_XDR_UNIT
;
239 rstrm
->frag_sent
= TRUE
;
240 if (!flush_out (rstrm
, FALSE
))
242 dest_lp
= (int32_t *) rstrm
->out_finger
;
243 rstrm
->out_finger
+= BYTES_PER_XDR_UNIT
;
245 *dest_lp
= htonl (*lp
);
249 static bool_t
/* must manage buffers, fragments, and records */
250 xdrrec_getbytes (xdrs
, addr
, len
)
255 RECSTREAM
*rstrm
= (RECSTREAM
*) xdrs
->x_private
;
260 current
= rstrm
->fbtbc
;
263 if (rstrm
->last_frag
)
265 if (!set_input_fragment (rstrm
))
269 current
= (len
< current
) ? len
: current
;
270 if (!get_input_bytes (rstrm
, addr
, current
))
273 rstrm
->fbtbc
-= current
;
280 xdrrec_putbytes (xdrs
, addr
, len
)
285 RECSTREAM
*rstrm
= (RECSTREAM
*) xdrs
->x_private
;
290 current
= rstrm
->out_boundry
- rstrm
->out_finger
;
291 current
= (len
< current
) ? len
: current
;
292 bcopy (addr
, rstrm
->out_finger
, current
);
293 rstrm
->out_finger
+= current
;
296 if (rstrm
->out_finger
== rstrm
->out_boundry
)
298 rstrm
->frag_sent
= TRUE
;
299 if (!flush_out (rstrm
, FALSE
))
307 xdrrec_getpos (const XDR
*xdrs
)
309 RECSTREAM
*rstrm
= (RECSTREAM
*) xdrs
->x_private
;
312 pos
= lseek ((int) rstrm
->tcp_handle
, (long) 0, 1);
318 pos
+= rstrm
->out_finger
- rstrm
->out_base
;
322 pos
-= rstrm
->in_boundry
- rstrm
->in_finger
;
333 xdrrec_setpos (xdrs
, pos
)
337 RECSTREAM
*rstrm
= (RECSTREAM
*) xdrs
->x_private
;
338 u_int currpos
= xdrrec_getpos (xdrs
);
339 int delta
= currpos
- pos
;
342 if ((int) currpos
!= -1)
347 newpos
= rstrm
->out_finger
- delta
;
348 if (newpos
> (caddr_t
) rstrm
->frag_header
&&
349 newpos
< rstrm
->out_boundry
)
351 rstrm
->out_finger
= newpos
;
357 newpos
= rstrm
->in_finger
- delta
;
358 if ((delta
< (int) (rstrm
->fbtbc
)) &&
359 (newpos
<= rstrm
->in_boundry
) &&
360 (newpos
>= rstrm
->in_base
))
362 rstrm
->in_finger
= newpos
;
363 rstrm
->fbtbc
-= delta
;
375 xdrrec_inline (XDR
*xdrs
, int len
)
377 RECSTREAM
*rstrm
= (RECSTREAM
*) xdrs
->x_private
;
384 if ((rstrm
->out_finger
+ len
) <= rstrm
->out_boundry
)
386 buf
= (long *) rstrm
->out_finger
;
387 rstrm
->out_finger
+= len
;
392 if ((len
<= rstrm
->fbtbc
) &&
393 ((rstrm
->in_finger
+ len
) <= rstrm
->in_boundry
))
395 buf
= (long *) rstrm
->in_finger
;
397 rstrm
->in_finger
+= len
;
408 xdrrec_destroy (xdrs
)
411 RECSTREAM
*rstrm
= (RECSTREAM
*) xdrs
->x_private
;
413 mem_free (rstrm
->the_buffer
,
414 rstrm
->sendsize
+ rstrm
->recvsize
+ BYTES_PER_XDR_UNIT
);
415 mem_free ((caddr_t
) rstrm
, sizeof (RECSTREAM
));
420 * Exported routines to manage xdr records
424 * Before reading (deserializing from the stream, one should always call
425 * this procedure to guarantee proper record alignment.
428 xdrrec_skiprecord (xdrs
)
431 RECSTREAM
*rstrm
= (RECSTREAM
*) xdrs
->x_private
;
433 while (rstrm
->fbtbc
> 0 || (!rstrm
->last_frag
))
435 if (!skip_input_bytes (rstrm
, rstrm
->fbtbc
))
438 if ((!rstrm
->last_frag
) && (!set_input_fragment (rstrm
)))
441 rstrm
->last_frag
= FALSE
;
446 * Lookahead function.
447 * Returns TRUE iff there is no more input in the buffer
448 * after consuming the rest of the current record.
454 RECSTREAM
*rstrm
= (RECSTREAM
*) xdrs
->x_private
;
456 while (rstrm
->fbtbc
> 0 || (!rstrm
->last_frag
))
458 if (!skip_input_bytes (rstrm
, rstrm
->fbtbc
))
461 if ((!rstrm
->last_frag
) && (!set_input_fragment (rstrm
)))
464 if (rstrm
->in_finger
== rstrm
->in_boundry
)
470 * The client must tell the package when an end-of-record has occurred.
471 * The second parameter tells whether the record should be flushed to the
472 * (output) tcp stream. (This lets the package support batched or
473 * pipelined procedure calls.) TRUE => immediate flush to tcp connection.
476 xdrrec_endofrecord (xdrs
, sendnow
)
480 RECSTREAM
*rstrm
= (RECSTREAM
*) xdrs
->x_private
;
481 u_long len
; /* fragment length */
483 if (sendnow
|| rstrm
->frag_sent
484 || rstrm
->out_finger
+ BYTES_PER_XDR_UNIT
>= rstrm
->out_boundry
)
486 rstrm
->frag_sent
= FALSE
;
487 return flush_out (rstrm
, TRUE
);
489 len
= (rstrm
->out_finger
- (char *) rstrm
->frag_header
490 - BYTES_PER_XDR_UNIT
);
491 *rstrm
->frag_header
= htonl ((u_long
) len
| LAST_FRAG
);
492 rstrm
->frag_header
= (u_int32_t
*) rstrm
->out_finger
;
493 rstrm
->out_finger
+= BYTES_PER_XDR_UNIT
;
499 * Internal useful routines
503 flush_out (RECSTREAM
*rstrm
, bool_t eor
)
505 u_long eormask
= (eor
== TRUE
) ? LAST_FRAG
: 0;
506 u_long len
= (rstrm
->out_finger
- (char *) rstrm
->frag_header
507 - BYTES_PER_XDR_UNIT
);
509 *rstrm
->frag_header
= htonl (len
| eormask
);
510 len
= rstrm
->out_finger
- rstrm
->out_base
;
511 if ((*(rstrm
->writeit
)) (rstrm
->tcp_handle
, rstrm
->out_base
, (int) len
)
514 rstrm
->frag_header
= (u_int32_t
*) rstrm
->out_base
;
515 rstrm
->out_finger
= (caddr_t
) rstrm
->out_base
+ BYTES_PER_XDR_UNIT
;
519 static bool_t
/* knows nothing about records! Only about input buffers */
520 fill_input_buf (RECSTREAM
*rstrm
)
526 where
= rstrm
->in_base
;
527 i
= (size_t) rstrm
->in_boundry
% BYTES_PER_XDR_UNIT
;
529 len
= rstrm
->in_size
- i
;
530 if ((len
= (*(rstrm
->readit
)) (rstrm
->tcp_handle
, where
, len
)) == -1)
532 rstrm
->in_finger
= where
;
534 rstrm
->in_boundry
= where
;
538 static bool_t
/* knows nothing about records! Only about input buffers */
540 get_input_bytes (RECSTREAM
*rstrm
, caddr_t addr
, int len
)
546 current
= rstrm
->in_boundry
- rstrm
->in_finger
;
549 if (!fill_input_buf (rstrm
))
553 current
= (len
< current
) ? len
: current
;
554 bcopy (rstrm
->in_finger
, addr
, current
);
555 rstrm
->in_finger
+= current
;
562 static bool_t
/* next two bytes of the input stream are treated as a header */
564 set_input_fragment (RECSTREAM
*rstrm
)
568 if (! get_input_bytes (rstrm
, (caddr_t
)&header
, BYTES_PER_XDR_UNIT
))
570 header
= ntohl (header
);
571 rstrm
->last_frag
= ((header
& LAST_FRAG
) == 0) ? FALSE
: TRUE
;
573 * Sanity check. Try not to accept wildly incorrect
574 * record sizes. Unfortunately, the only record size
575 * we can positively identify as being 'wildly incorrect'
576 * is zero. Ridiculously large record sizes may look wrong,
577 * but we don't have any way to be certain that they aren't
578 * what the client actually intended to send us.
580 if ((header
& (~LAST_FRAG
)) == 0)
582 rstrm
->fbtbc
= header
& ~LAST_FRAG
;
586 static bool_t
/* consumes input bytes; knows nothing about records! */
588 skip_input_bytes (RECSTREAM
*rstrm
, long cnt
)
594 current
= rstrm
->in_boundry
- rstrm
->in_finger
;
597 if (!fill_input_buf (rstrm
))
601 current
= (cnt
< current
) ? cnt
: current
;
602 rstrm
->in_finger
+= current
;
610 fix_buf_size (u_int s
)