+++ /dev/null
-/*
- * Copyright (c) 2007, 2009 Apple Inc. All rights reserved.
- *
- * @APPLE_LICENSE_HEADER_START@
- *
- * This file contains Original Code and/or Modifications of Original Code
- * as defined in and that are subject to the Apple Public Source License
- * Version 2.0 (the 'License'). You may not use this file except in
- * compliance with the License. Please obtain a copy of the License at
- * http://www.opensource.apple.com/apsl/ and read it before using this
- * file.
- *
- * The Original Code and all software distributed under the License are
- * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
- * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
- * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
- * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
- * Please see the License for the specific language governing rights and
- * limitations under the License.
- *
- * @APPLE_LICENSE_HEADER_END@
- */
-
-/*
- * Copyright (c) 2001 Daniel M. Eischen <deischen@freebsd.org>
- * All rights reserved.
- *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions
- * are met:
- * 1. Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- * 2. Neither the name of the author 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 AUTHOR 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 AUTHOR 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.
- */
-
-#if defined(__i386__)
-
-#include <sys/cdefs.h>
-
-#include <sys/param.h>
-#include <sys/signal.h>
-#include <sys/ucontext.h>
-
-#include <errno.h>
-#include <stdarg.h>
-#include <stdlib.h>
-#include <ucontext.h>
-#include <unistd.h>
-
-/* Prototypes */
-extern void _ctx_start(ucontext_t *, int argc, ...);
-
-void
-_ctx_done (ucontext_t *ucp)
-{
- if (ucp->uc_link == NULL)
- exit(0);
- else {
- /*
- * Since this context has finished, don't allow it
- * to be restarted without being reinitialized (via
- * setcontext or swapcontext).
- */
- ucp->uc_mcsize = 0;
-
- /* Set context to next one in link */
- /* XXX - what to do for error, abort? */
- setcontext((const ucontext_t *)ucp->uc_link);
- LIBC_ABORT("setcontext failed"); /* should never get here */
- }
-}
-
-void
-makecontext(ucontext_t *ucp, void (*start)(), int argc, ...)
-{
- va_list ap;
- char *stack_top;
- intptr_t *argp;
- int i;
-
- if (ucp == NULL)
- return;
- else if ((ucp->uc_stack.ss_sp == NULL) ||
- (ucp->uc_stack.ss_size < MINSIGSTKSZ)) {
- /*
- * This should really return -1 with errno set to ENOMEM
- * or something, but the spec says that makecontext is
- * a void function. At least make sure that the context
- * isn't valid so it can't be used without an error.
- */
- ucp->uc_mcsize = 0;
- }
- /* XXX - Do we want to sanity check argc? */
- else if ((argc < 0) || (argc > NCARGS)) {
- ucp->uc_mcsize = 0;
- }
- /* Make sure the context is valid. */
- else {
- /*
- * Arrange the stack as follows:
- *
- * _ctx_start() - context start wrapper
- * start() - user start routine
- * arg1 - first argument, aligned(16)
- * ...
- * argn
- * ucp - this context, %ebp points here
- *
- * When the context is started, control will return to
- * the context start wrapper which will pop the user
- * start routine from the top of the stack. After that,
- * the top of the stack will be setup with all arguments
- * necessary for calling the start routine. When the
- * start routine returns, the context wrapper then sets
- * the stack pointer to %ebp which was setup to point to
- * the base of the stack (and where ucp is stored). It
- * will then call _ctx_done() to swap in the next context
- * (uc_link != 0) or exit the program (uc_link == 0).
- */
- mcontext_t mc;
-
- stack_top = (char *)(ucp->uc_stack.ss_sp +
- ucp->uc_stack.ss_size - sizeof(intptr_t));
-
- /*
- * Adjust top of stack to allow for 3 pointers (return
- * address, _ctx_start, and ucp) and argc arguments.
- * We allow the arguments to be pointers also. The first
- * argument to the user function must be properly aligned.
- */
- stack_top = stack_top - (sizeof(intptr_t) * (1 + argc));
- stack_top = (char *)((unsigned)stack_top & ~15);
- stack_top = stack_top - (2 * sizeof(intptr_t));
- argp = (intptr_t *)stack_top;
-
- /*
- * Setup the top of the stack with the user start routine
- * followed by all of its aguments and the pointer to the
- * ucontext. We need to leave a spare spot at the top of
- * the stack because setcontext will move eip to the top
- * of the stack before returning.
- */
- *argp = (intptr_t)_ctx_start; /* overwritten with same value */
- argp++;
- *argp = (intptr_t)start;
- argp++;
-
- /* Add all the arguments: */
- va_start(ap, argc);
- for (i = 0; i < argc; i++) {
- *argp = va_arg(ap, intptr_t);
- argp++;
- }
- va_end(ap);
-
- /* The ucontext is placed at the bottom of the stack. */
- *argp = (intptr_t)ucp;
-
- /*
- * Set the machine context to point to the top of the
- * stack and the program counter to the context start
- * wrapper. Note that setcontext() pushes the return
- * address onto the top of the stack, so allow for this
- * by adjusting the stack downward 1 slot. Also set
- * %esi to point to the base of the stack where ucp
- * is stored.
- */
- mc = ucp->uc_mcontext;
-
- mc->__ss.__esi = (int)argp;
- mc->__ss.__ebp = 0;
- mc->__ss.__esp = (int)stack_top + sizeof(caddr_t);
- mc->__ss.__eip = (int)_ctx_start;
- }
-}
-
-#endif /* __i386__ */
projects / apple / libc.git / blobdiff