33c91738e5
interacts with the userspace file server:
* since the kernel-user communication is not purely request-response
anymore (hasn't been since 2006), try to rename some "request" to
"message". more similar mangling will take place in the future.
* completely rework how messages are allocated. previously most of
them were borrowed from the stack (originally *all* of them),
but now always allocate dynamically. this makes the structure
of the code much cleaner. also makes it possible to fix a
locking order violation. it enables plenty of future enhancements.
* start generalizing the transport interface to be independent of puffs
* move transport interface to read/write instead of ioctl. the
old one had legacy design problems, and besides, ioctl's suck.
implement a very generic version for now; this will be
worked on later hopefully some day reaching "highly optimized".
* implement libpuffs support behind existing library request
interfaces. this will change eventually (I hate those interfaces)
158 lines
4.0 KiB
C
158 lines
4.0 KiB
C
/* $NetBSD: callcontext.c,v 1.8 2007/10/11 19:41:14 pooka Exp $ */
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/*
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* Copyright (c) 2006 Antti Kantee. All Rights Reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS
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* OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
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* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
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* DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
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* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#include <sys/cdefs.h>
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#if !defined(lint)
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__RCSID("$NetBSD: callcontext.c,v 1.8 2007/10/11 19:41:14 pooka Exp $");
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#endif /* !lint */
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#include <sys/types.h>
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#include <assert.h>
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#include <puffs.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <ucontext.h>
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#include "puffs_priv.h"
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/*
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* user stuff
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*/
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void
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puffs_cc_yield(struct puffs_cc *pcc)
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{
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assert(pcc->pcc_flags & PCC_REALCC);
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pcc->pcc_flags &= ~PCC_BORROWED;
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/* romanes eunt domus */
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swapcontext(&pcc->pcc_uc, &pcc->pcc_uc_ret);
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}
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void
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puffs_cc_continue(struct puffs_cc *pcc)
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{
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assert(pcc->pcc_flags & PCC_REALCC);
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/* ramble on */
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swapcontext(&pcc->pcc_uc_ret, &pcc->pcc_uc);
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}
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/*
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* "Borrows" pcc, *NOT* called from pcc owner. Acts like continue.
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* So the idea is to use this, give something the context back to
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* run to completion and then jump back to where ever this was called
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* from after the op dispatching is complete (or if the pcc decides to
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* yield again).
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*/
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void
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puffs_goto(struct puffs_cc *loanpcc)
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{
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assert(loanpcc->pcc_flags & PCC_REALCC);
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loanpcc->pcc_flags |= PCC_BORROWED;
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swapcontext(&loanpcc->pcc_uc_ret, &loanpcc->pcc_uc);
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}
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struct puffs_usermount *
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puffs_cc_getusermount(struct puffs_cc *pcc)
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{
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return pcc->pcc_pu;
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}
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void *
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puffs_cc_getspecific(struct puffs_cc *pcc)
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{
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return puffs_getspecific(pcc->pcc_pu);
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}
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struct puffs_cc *
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puffs_cc_create(struct puffs_usermount *pu)
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{
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struct puffs_cc *volatile pcc;
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stack_t *st;
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pcc = malloc(sizeof(struct puffs_cc));
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if (!pcc)
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return NULL;
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memset(pcc, 0, sizeof(struct puffs_cc));
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pcc->pcc_pu = pu;
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pcc->pcc_flags = PCC_REALCC;
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/* initialize both ucontext's */
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if (getcontext(&pcc->pcc_uc) == -1) {
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free(pcc);
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return NULL;
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}
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if (getcontext(&pcc->pcc_uc_ret) == -1) {
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free(pcc);
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return NULL;
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}
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/* return here. it won't actually be "here" due to swapcontext() */
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pcc->pcc_uc.uc_link = &pcc->pcc_uc_ret;
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/* allocate stack for execution */
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st = &pcc->pcc_uc.uc_stack;
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st->ss_sp = pcc->pcc_stack = malloc(pu->pu_cc_stacksize);
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if (st->ss_sp == NULL) {
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free(pcc);
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return NULL;
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}
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st->ss_size = pu->pu_cc_stacksize;
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st->ss_flags = 0;
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/*
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* Give us an initial context to jump to.
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*
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* XXX: Our manual page says that portable code shouldn't rely on
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* being able to pass pointers through makecontext(). kjk says
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* that NetBSD code doesn't need to worry about this. uwe says
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* it would be like putting a "keep away from children" sign on a
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* box of toys. I didn't ask what simon says; he's probably busy
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* "fixing" typos in comments.
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*/
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makecontext(&pcc->pcc_uc, (void *)puffs_calldispatcher,
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1, (uintptr_t)pcc);
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return pcc;
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}
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void
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puffs_cc_destroy(struct puffs_cc *pcc)
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{
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free(pcc->pcc_stack);
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free(pcc);
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}
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