diff options
Diffstat (limited to 'lib/libc/i386/gen/makecontext.c')
-rw-r--r-- | lib/libc/i386/gen/makecontext.c | 163 |
1 files changed, 0 insertions, 163 deletions
diff --git a/lib/libc/i386/gen/makecontext.c b/lib/libc/i386/gen/makecontext.c deleted file mode 100644 index 167cb12..0000000 --- a/lib/libc/i386/gen/makecontext.c +++ /dev/null @@ -1,163 +0,0 @@ -/* - * 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. - */ - -#include <sys/cdefs.h> -__FBSDID("$FreeBSD$"); - -#include <sys/param.h> -#include <sys/signal.h> -#include <sys/ucontext.h> - -#include <errno.h> -#include <stdarg.h> -#include <stdlib.h> -#include <unistd.h> - -/* Prototypes */ -extern void _ctx_start(ucontext_t *, int argc, ...); - - -__weak_reference(__makecontext, makecontext); - -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_mcontext.mc_len = 0; - - /* Set context to next one in link */ - /* XXX - what to do for error, abort? */ - setcontext((const ucontext_t *)ucp->uc_link); - abort(); /* should never get here */ - } -} - -void -__makecontext(ucontext_t *ucp, void (*start)(void), 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_mcontext.mc_len = 0; - } - /* XXX - Do we want to sanity check argc? */ - else if ((argc < 0) || (argc > NCARGS)) { - ucp->uc_mcontext.mc_len = 0; - } - /* Make sure the context is valid. */ - else if (ucp->uc_mcontext.mc_len == sizeof(mcontext_t)) { - /* - * 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). - */ - 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. - */ - ucp->uc_mcontext.mc_esi = (int)argp; - ucp->uc_mcontext.mc_ebp = 0; - ucp->uc_mcontext.mc_esp = (int)stack_top + sizeof(caddr_t); - ucp->uc_mcontext.mc_eip = (int)_ctx_start; - } -} |