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Diffstat (limited to 'src/pmap_prot2.c')
-rw-r--r-- | src/pmap_prot2.c | 131 |
1 files changed, 131 insertions, 0 deletions
diff --git a/src/pmap_prot2.c b/src/pmap_prot2.c new file mode 100644 index 0000000..5583ff0 --- /dev/null +++ b/src/pmap_prot2.c @@ -0,0 +1,131 @@ +/* + * Copyright (c) 2009, Sun Microsystems, Inc. + * All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions are met: + * - Redistributions of source code must retain the above copyright notice, + * this list of conditions and the following disclaimer. + * - Redistributions in binary form must reproduce the above copyright notice, + * this list of conditions and the following disclaimer in the documentation + * and/or other materials provided with the distribution. + * - Neither the name of Sun Microsystems, Inc. nor the names of its + * contributors may be used to endorse or promote products derived + * from this software without specific prior written permission. + * + * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" + * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE + * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE + * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE + * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR + * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF + * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS + * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN + * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) + * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE + * POSSIBILITY OF SUCH DAMAGE. + */ + +/* + * pmap_prot2.c + * Protocol for the local binder service, or pmap. + * + * Copyright (C) 1984, Sun Microsystems, Inc. + */ + +#include <assert.h> + +#include <rpc/types.h> +#include <rpc/xdr.h> +#include <rpc/pmap_prot.h> + + +/* + * What is going on with linked lists? (!) + * First recall the link list declaration from pmap_prot.h: + * + * struct pmaplist { + * struct pmap pml_map; + * struct pmaplist *pml_map; + * }; + * + * Compare that declaration with a corresponding xdr declaration that + * is (a) pointer-less, and (b) recursive: + * + * typedef union switch (bool_t) { + * + * case TRUE: struct { + * struct pmap; + * pmaplist_t foo; + * }; + * + * case FALSE: struct {}; + * } pmaplist_t; + * + * Notice that the xdr declaration has no nxt pointer while + * the C declaration has no bool_t variable. The bool_t can be + * interpreted as ``more data follows me''; if FALSE then nothing + * follows this bool_t; if TRUE then the bool_t is followed by + * an actual struct pmap, and then (recursively) by the + * xdr union, pamplist_t. + * + * This could be implemented via the xdr_union primitive, though this + * would cause a one recursive call per element in the list. Rather than do + * that we can ``unwind'' the recursion + * into a while loop and do the union arms in-place. + * + * The head of the list is what the C programmer wishes to past around + * the net, yet is the data that the pointer points to which is interesting; + * this sounds like a job for xdr_reference! + */ +bool_t +xdr_pmaplist(xdrs, rp) + XDR *xdrs; + struct pmaplist **rp; +{ + /* + * more_elements is pre-computed in case the direction is + * XDR_ENCODE or XDR_FREE. more_elements is overwritten by + * xdr_bool when the direction is XDR_DECODE. + */ + bool_t more_elements; + int freeing; + struct pmaplist **next = NULL; /* pacify gcc */ + + assert(xdrs != NULL); + assert(rp != NULL); + + freeing = (xdrs->x_op == XDR_FREE); + + for (;;) { + more_elements = (bool_t)(*rp != NULL); + if (! xdr_bool(xdrs, &more_elements)) + return (FALSE); + if (! more_elements) + return (TRUE); /* we are done */ + /* + * the unfortunate side effect of non-recursion is that in + * the case of freeing we must remember the next object + * before we free the current object ... + */ + if (freeing) + next = &((*rp)->pml_next); + if (! xdr_reference(xdrs, (caddr_t *)rp, + (u_int)sizeof(struct pmaplist), (xdrproc_t)xdr_pmap)) + return (FALSE); + rp = (freeing) ? next : &((*rp)->pml_next); + } +} + + +/* + * xdr_pmaplist_ptr() is specified to take a PMAPLIST *, but is identical in + * functionality to xdr_pmaplist(). + */ +bool_t +xdr_pmaplist_ptr(xdrs, rp) + XDR *xdrs; + struct pmaplist *rp; +{ + return xdr_pmaplist(xdrs, (struct pmaplist **)(void *)rp); +} |