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31 * xdr_rec.c, Implements TCP/IP based XDR streams with a "record marking"
32 * layer above tcp (for rpc's use).
34 * Copyright (C) 1984, Sun Microsystems, Inc.
36 * These routines interface XDRSTREAMS to a tcp/ip connection.
37 * There is a record marking layer between the xdr stream
38 * and the tcp transport level. A record is composed on one or more
39 * record fragments. A record fragment is a thirty-two bit header followed
40 * by n bytes of data, where n is contained in the header. The header
41 * is represented as a htonl(u_long). The high order bit encodes
42 * whether or not the fragment is the last fragment of the record
43 * (1 => fragment is last, 0 => more fragments to follow.
44 * The other 31 bits encode the byte length of the fragment.
54 # include <libio/iolibio.h>
55 # define fputs(s, f) _IO_fputs (s, f)
58 static bool_t xdrrec_getlong (XDR *, long *);
59 static bool_t xdrrec_putlong (XDR *, const long *);
60 static bool_t xdrrec_getbytes (XDR *, caddr_t, u_int);
61 static bool_t xdrrec_putbytes (XDR *, const char *, u_int);
62 static u_int xdrrec_getpos (const XDR *);
63 static bool_t xdrrec_setpos (XDR *, u_int);
64 static int32_t *xdrrec_inline (XDR *, int);
65 static void xdrrec_destroy (XDR *);
66 static bool_t xdrrec_getint32 (XDR *, int32_t *);
67 static bool_t xdrrec_putint32 (XDR *, const int32_t *);
69 static const struct xdr_ops xdrrec_ops = {
83 * A record is composed of one or more record fragments.
84 * A record fragment is a two-byte header followed by zero to
85 * 2**32-1 bytes. The header is treated as a long unsigned and is
86 * encode/decoded to the network via htonl/ntohl. The low order 31 bits
87 * are a byte count of the fragment. The highest order bit is a boolean:
88 * 1 => this fragment is the last fragment of the record,
89 * 0 => this fragment is followed by more fragment(s).
91 * The fragment/record machinery is not general; it is constructed to
92 * meet the needs of xdr and rpc based on tcp.
95 #define LAST_FRAG (1UL << 31)
97 typedef struct rec_strm
104 int (*writeit) (char *, char *, int);
105 caddr_t out_base; /* output buffer (points to frag header) */
106 caddr_t out_finger; /* next output position */
107 caddr_t out_boundry; /* data cannot up to this address */
108 u_int32_t *frag_header; /* beginning of curren fragment */
109 bool_t frag_sent; /* true if buffer sent in middle of record */
113 int (*readit) (char *, char *, int);
114 u_long in_size; /* fixed size of the input buffer */
116 caddr_t in_finger; /* location of next byte to be had */
117 caddr_t in_boundry; /* can read up to this location */
118 long fbtbc; /* fragment bytes to be consumed */
125 static u_int fix_buf_size (u_int) internal_function;
126 static bool_t skip_input_bytes (RECSTREAM *, long) internal_function;
127 static bool_t flush_out (RECSTREAM *, bool_t) internal_function;
128 static bool_t set_input_fragment (RECSTREAM *) internal_function;
129 static bool_t get_input_bytes (RECSTREAM *, caddr_t, int) internal_function;
132 * Create an xdr handle for xdrrec
133 * xdrrec_create fills in xdrs. Sendsize and recvsize are
134 * send and recv buffer sizes (0 => use default).
135 * tcp_handle is an opaque handle that is passed as the first parameter to
136 * the procedures readit and writeit. Readit and writeit are read and
137 * write respectively. They are like the system
138 * calls expect that they take an opaque handle rather than an fd.
141 xdrrec_create (XDR *xdrs, u_int sendsize,
142 u_int recvsize, caddr_t tcp_handle,
143 int (*readit) (char *, char *, int),
144 int (*writeit) (char *, char *, int))
146 RECSTREAM *rstrm = (RECSTREAM *) mem_alloc (sizeof (RECSTREAM));
151 (void) fputs (_("xdrrec_create: out of memory\n"), stderr);
153 * This is bad. Should rework xdrrec_create to
154 * return a handle, and in this case return NULL
159 * adjust sizes and allocate buffer quad byte aligned
161 rstrm->sendsize = sendsize = fix_buf_size (sendsize);
162 rstrm->recvsize = recvsize = fix_buf_size (recvsize);
163 rstrm->the_buffer = mem_alloc (sendsize + recvsize + BYTES_PER_XDR_UNIT);
164 if (rstrm->the_buffer == NULL)
166 (void) fputs (_("xdrrec_create: out of memory\n"), stderr);
169 tmp = rstrm->the_buffer;
170 if ((size_t)tmp % BYTES_PER_XDR_UNIT)
171 tmp += BYTES_PER_XDR_UNIT - (size_t)tmp % BYTES_PER_XDR_UNIT;
172 rstrm->out_base = tmp;
173 rstrm->in_base = tmp + sendsize;
177 /* We have to add the const since the `struct xdr_ops' in `struct XDR'
179 xdrs->x_ops = (struct xdr_ops *) &xdrrec_ops;
180 xdrs->x_private = (caddr_t) rstrm;
181 rstrm->tcp_handle = tcp_handle;
182 rstrm->readit = readit;
183 rstrm->writeit = writeit;
184 rstrm->out_finger = rstrm->out_boundry = rstrm->out_base;
185 rstrm->frag_header = (u_int32_t *) rstrm->out_base;
186 rstrm->out_finger += 4;
187 rstrm->out_boundry += sendsize;
188 rstrm->frag_sent = FALSE;
189 rstrm->in_size = recvsize;
190 rstrm->in_boundry = rstrm->in_base;
191 rstrm->in_finger = (rstrm->in_boundry += recvsize);
193 rstrm->last_frag = TRUE;
198 * The routines defined below are the xdr ops which will go into the
199 * xdr handle filled in by xdrrec_create.
203 xdrrec_getlong (XDR *xdrs, long *lp)
205 RECSTREAM *rstrm = (RECSTREAM *) xdrs->x_private;
206 int32_t *buflp = (int32_t *) rstrm->in_finger;
209 /* first try the inline, fast case */
210 if (rstrm->fbtbc >= BYTES_PER_XDR_UNIT &&
211 rstrm->in_boundry - (char *) buflp >= BYTES_PER_XDR_UNIT)
213 *lp = (int32_t) ntohl (*buflp);
214 rstrm->fbtbc -= BYTES_PER_XDR_UNIT;
215 rstrm->in_finger += BYTES_PER_XDR_UNIT;
219 if (!xdrrec_getbytes (xdrs, (caddr_t) & mylong,
222 *lp = (int32_t) ntohl (mylong);
228 xdrrec_putlong (XDR *xdrs, const long *lp)
230 RECSTREAM *rstrm = (RECSTREAM *) xdrs->x_private;
231 int32_t *dest_lp = (int32_t *) rstrm->out_finger;
233 if ((rstrm->out_finger += BYTES_PER_XDR_UNIT) > rstrm->out_boundry)
236 * this case should almost never happen so the code is
239 rstrm->out_finger -= BYTES_PER_XDR_UNIT;
240 rstrm->frag_sent = TRUE;
241 if (!flush_out (rstrm, FALSE))
243 dest_lp = (int32_t *) rstrm->out_finger;
244 rstrm->out_finger += BYTES_PER_XDR_UNIT;
246 *dest_lp = htonl (*lp);
250 static bool_t /* must manage buffers, fragments, and records */
251 xdrrec_getbytes (XDR *xdrs, caddr_t addr, u_int len)
253 RECSTREAM *rstrm = (RECSTREAM *) xdrs->x_private;
258 current = rstrm->fbtbc;
261 if (rstrm->last_frag)
263 if (!set_input_fragment (rstrm))
267 current = (len < current) ? len : current;
268 if (!get_input_bytes (rstrm, addr, current))
271 rstrm->fbtbc -= current;
278 xdrrec_putbytes (XDR *xdrs, const char *addr, u_int len)
280 RECSTREAM *rstrm = (RECSTREAM *) xdrs->x_private;
285 current = rstrm->out_boundry - rstrm->out_finger;
286 current = (len < current) ? len : current;
287 bcopy (addr, rstrm->out_finger, current);
288 rstrm->out_finger += current;
291 if (rstrm->out_finger == rstrm->out_boundry && len > 0)
293 rstrm->frag_sent = TRUE;
294 if (!flush_out (rstrm, FALSE))
302 xdrrec_getpos (const XDR *xdrs)
304 RECSTREAM *rstrm = (RECSTREAM *) xdrs->x_private;
307 pos = __lseek ((int) (long) rstrm->tcp_handle, (long) 0, 1);
313 pos += rstrm->out_finger - rstrm->out_base;
317 pos -= rstrm->in_boundry - rstrm->in_finger;
328 xdrrec_setpos (XDR *xdrs, u_int pos)
330 RECSTREAM *rstrm = (RECSTREAM *) xdrs->x_private;
331 u_int currpos = xdrrec_getpos (xdrs);
332 int delta = currpos - pos;
335 if ((int) currpos != -1)
340 newpos = rstrm->out_finger - delta;
341 if (newpos > (caddr_t) rstrm->frag_header &&
342 newpos < rstrm->out_boundry)
344 rstrm->out_finger = newpos;
350 newpos = rstrm->in_finger - delta;
351 if ((delta < (int) (rstrm->fbtbc)) &&
352 (newpos <= rstrm->in_boundry) &&
353 (newpos >= rstrm->in_base))
355 rstrm->in_finger = newpos;
356 rstrm->fbtbc -= delta;
368 xdrrec_inline (XDR *xdrs, int len)
370 RECSTREAM *rstrm = (RECSTREAM *) xdrs->x_private;
377 if ((rstrm->out_finger + len) <= rstrm->out_boundry)
379 buf = (int32_t *) rstrm->out_finger;
380 rstrm->out_finger += len;
385 if ((len <= rstrm->fbtbc) &&
386 ((rstrm->in_finger + len) <= rstrm->in_boundry))
388 buf = (int32_t *) rstrm->in_finger;
390 rstrm->in_finger += len;
401 xdrrec_destroy (XDR *xdrs)
403 RECSTREAM *rstrm = (RECSTREAM *) xdrs->x_private;
405 mem_free (rstrm->the_buffer,
406 rstrm->sendsize + rstrm->recvsize + BYTES_PER_XDR_UNIT);
407 mem_free ((caddr_t) rstrm, sizeof (RECSTREAM));
411 xdrrec_getint32 (XDR *xdrs, int32_t *ip)
413 RECSTREAM *rstrm = (RECSTREAM *) xdrs->x_private;
414 int32_t *bufip = (int32_t *) rstrm->in_finger;
417 /* first try the inline, fast case */
418 if (rstrm->fbtbc >= BYTES_PER_XDR_UNIT &&
419 rstrm->in_boundry - (char *) bufip >= BYTES_PER_XDR_UNIT)
421 *ip = ntohl (*bufip);
422 rstrm->fbtbc -= BYTES_PER_XDR_UNIT;
423 rstrm->in_finger += BYTES_PER_XDR_UNIT;
427 if (!xdrrec_getbytes (xdrs, (caddr_t) &mylong,
430 *ip = ntohl (mylong);
436 xdrrec_putint32 (XDR *xdrs, const int32_t *ip)
438 RECSTREAM *rstrm = (RECSTREAM *) xdrs->x_private;
439 int32_t *dest_ip = (int32_t *) rstrm->out_finger;
441 if ((rstrm->out_finger += BYTES_PER_XDR_UNIT) > rstrm->out_boundry)
444 * this case should almost never happen so the code is
447 rstrm->out_finger -= BYTES_PER_XDR_UNIT;
448 rstrm->frag_sent = TRUE;
449 if (!flush_out (rstrm, FALSE))
451 dest_ip = (int32_t *) rstrm->out_finger;
452 rstrm->out_finger += BYTES_PER_XDR_UNIT;
454 *dest_ip = htonl (*ip);
459 * Exported routines to manage xdr records
463 * Before reading (deserializing from the stream, one should always call
464 * this procedure to guarantee proper record alignment.
467 xdrrec_skiprecord (XDR *xdrs)
469 RECSTREAM *rstrm = (RECSTREAM *) xdrs->x_private;
471 while (rstrm->fbtbc > 0 || (!rstrm->last_frag))
473 if (!skip_input_bytes (rstrm, rstrm->fbtbc))
476 if ((!rstrm->last_frag) && (!set_input_fragment (rstrm)))
479 rstrm->last_frag = FALSE;
484 * Lookahead function.
485 * Returns TRUE iff there is no more input in the buffer
486 * after consuming the rest of the current record.
489 xdrrec_eof (XDR *xdrs)
491 RECSTREAM *rstrm = (RECSTREAM *) xdrs->x_private;
493 while (rstrm->fbtbc > 0 || (!rstrm->last_frag))
495 if (!skip_input_bytes (rstrm, rstrm->fbtbc))
498 if ((!rstrm->last_frag) && (!set_input_fragment (rstrm)))
501 if (rstrm->in_finger == rstrm->in_boundry)
507 * The client must tell the package when an end-of-record has occurred.
508 * The second parameter tells whether the record should be flushed to the
509 * (output) tcp stream. (This lets the package support batched or
510 * pipelined procedure calls.) TRUE => immediate flush to tcp connection.
513 xdrrec_endofrecord (XDR *xdrs, bool_t sendnow)
515 RECSTREAM *rstrm = (RECSTREAM *) xdrs->x_private;
516 u_long len; /* fragment length */
518 if (sendnow || rstrm->frag_sent
519 || rstrm->out_finger + BYTES_PER_XDR_UNIT >= rstrm->out_boundry)
521 rstrm->frag_sent = FALSE;
522 return flush_out (rstrm, TRUE);
524 len = (rstrm->out_finger - (char *) rstrm->frag_header
525 - BYTES_PER_XDR_UNIT);
526 *rstrm->frag_header = htonl ((u_long) len | LAST_FRAG);
527 rstrm->frag_header = (u_int32_t *) rstrm->out_finger;
528 rstrm->out_finger += BYTES_PER_XDR_UNIT;
534 * Internal useful routines
538 flush_out (RECSTREAM *rstrm, bool_t eor)
540 u_long eormask = (eor == TRUE) ? LAST_FRAG : 0;
541 u_long len = (rstrm->out_finger - (char *) rstrm->frag_header
542 - BYTES_PER_XDR_UNIT);
544 *rstrm->frag_header = htonl (len | eormask);
545 len = rstrm->out_finger - rstrm->out_base;
546 if ((*(rstrm->writeit)) (rstrm->tcp_handle, rstrm->out_base, (int) len)
549 rstrm->frag_header = (u_int32_t *) rstrm->out_base;
550 rstrm->out_finger = (caddr_t) rstrm->out_base + BYTES_PER_XDR_UNIT;
554 static bool_t /* knows nothing about records! Only about input buffers */
555 fill_input_buf (RECSTREAM *rstrm)
561 where = rstrm->in_base;
562 i = (size_t) rstrm->in_boundry % BYTES_PER_XDR_UNIT;
564 len = rstrm->in_size - i;
565 if ((len = (*(rstrm->readit)) (rstrm->tcp_handle, where, len)) == -1)
567 rstrm->in_finger = where;
569 rstrm->in_boundry = where;
573 static bool_t /* knows nothing about records! Only about input buffers */
575 get_input_bytes (RECSTREAM *rstrm, caddr_t addr, int len)
581 current = rstrm->in_boundry - rstrm->in_finger;
584 if (!fill_input_buf (rstrm))
588 current = (len < current) ? len : current;
589 bcopy (rstrm->in_finger, addr, current);
590 rstrm->in_finger += current;
597 static bool_t /* next two bytes of the input stream are treated as a header */
599 set_input_fragment (RECSTREAM *rstrm)
603 if (! get_input_bytes (rstrm, (caddr_t)&header, BYTES_PER_XDR_UNIT))
605 header = ntohl (header);
606 rstrm->last_frag = ((header & LAST_FRAG) == 0) ? FALSE : TRUE;
608 * Sanity check. Try not to accept wildly incorrect fragment
609 * sizes. Unfortunately, only a size of zero can be identified as
610 * 'wildely incorrect', and this only, if it is not the last
611 * fragment of a message. Ridiculously large fragment sizes may look
612 * wrong, but we don't have any way to be certain that they aren't
613 * what the client actually intended to send us. Many existing RPC
614 * implementations may sent a fragment of size zero as the last
615 * fragment of a message.
619 rstrm->fbtbc = header & ~LAST_FRAG;
623 static bool_t /* consumes input bytes; knows nothing about records! */
625 skip_input_bytes (RECSTREAM *rstrm, long cnt)
631 current = rstrm->in_boundry - rstrm->in_finger;
634 if (!fill_input_buf (rstrm))
638 current = (cnt < current) ? cnt : current;
639 rstrm->in_finger += current;
647 fix_buf_size (u_int s)