diff options
author | peter <peter@FreeBSD.org> | 2000-07-29 07:14:04 +0000 |
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committer | peter <peter@FreeBSD.org> | 2000-07-29 07:14:04 +0000 |
commit | 6a75b120d26bc19be2c1603edb4fbfdc4b30f2a8 (patch) | |
tree | 2527ee7d4d460805ebd914733e4057ebb5567705 | |
parent | 7588cd1d2a1eaa6ec1813de0ea097c7de9759ae4 (diff) | |
download | FreeBSD-src-6a75b120d26bc19be2c1603edb4fbfdc4b30f2a8.zip FreeBSD-src-6a75b120d26bc19be2c1603edb4fbfdc4b30f2a8.tar.gz |
rfork(2) wrapper for simple rfork-style threads. I have lost count of
the number of times I have given this to people and got asked: why isn't
it in libc? It is impossible to do this without assembler glue to reset
the stack for the new child process.
int rfork_thread(flags, stack_addr, start_fnc, start_arg)
int flags; Flags to rfork system call. See rfork(2).
void *stack_addr; Top of stack for thread.
int (*start_fnc)(void *); Address of thread function to call in child.
void *start_arg; Argument to pass to the thread function in child.
This is deliberately not documented or prototyped in includes until the
corresponding alpha version is written.
-rw-r--r-- | lib/libc/amd64/gen/Makefile.inc | 2 | ||||
-rw-r--r-- | lib/libc/i386/gen/Makefile.inc | 2 | ||||
-rw-r--r-- | lib/libc/i386/gen/rfork_thread.S | 112 |
3 files changed, 114 insertions, 2 deletions
diff --git a/lib/libc/amd64/gen/Makefile.inc b/lib/libc/amd64/gen/Makefile.inc index f2506fd..66b0759 100644 --- a/lib/libc/amd64/gen/Makefile.inc +++ b/lib/libc/amd64/gen/Makefile.inc @@ -2,4 +2,4 @@ # $FreeBSD$ SRCS+= _setjmp.S alloca.S fabs.S frexp.c infinity.c isinf.c ldexp.c modf.S \ - setjmp.S sigsetjmp.S + rfork_thread.S setjmp.S sigsetjmp.S diff --git a/lib/libc/i386/gen/Makefile.inc b/lib/libc/i386/gen/Makefile.inc index f2506fd..66b0759 100644 --- a/lib/libc/i386/gen/Makefile.inc +++ b/lib/libc/i386/gen/Makefile.inc @@ -2,4 +2,4 @@ # $FreeBSD$ SRCS+= _setjmp.S alloca.S fabs.S frexp.c infinity.c isinf.c ldexp.c modf.S \ - setjmp.S sigsetjmp.S + rfork_thread.S setjmp.S sigsetjmp.S diff --git a/lib/libc/i386/gen/rfork_thread.S b/lib/libc/i386/gen/rfork_thread.S new file mode 100644 index 0000000..674f86e --- /dev/null +++ b/lib/libc/i386/gen/rfork_thread.S @@ -0,0 +1,112 @@ +/*- + * Copyright (c) 2000 Peter Wemm <peter@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. 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. + * + * 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. + * + * $FreeBSD$ + */ + +/* + * With thanks to John Dyson for the original version of this. + */ + +#include <SYS.h> + +/* + * 8 12 16 20 + * rfork_thread(flags, stack_addr, start_fnc, start_arg); + * + * flags: Flags to rfork system call. See rfork(2). + * stack_addr: Top of stack for thread. + * start_fnc: Address of thread function to call in child. + * start_arg: Argument to pass to the thread function in child. + */ + +ENTRY(rfork_thread) + pushl %ebp + movl %esp, %ebp + pushl %esi + + /* + * Push thread info onto the new thread's stack + */ + movl 12(%ebp), %esi # get stack addr + + subl $4, %esi + movl 20(%ebp), %eax # get start argument + movl %eax, (%esi) + + subl $4, %esi + movl 16(%ebp), %eax # get start thread address + movl %eax, (%esi) + + /* + * Prepare and execute the thread creation syscall + */ + pushl 12(%ebp) + pushl 8(%ebp) + pushl %esi + leal SYS_rfork, %eax + KERNCALL + jb 2f + + /* + * Check to see if we are in the parent or child + */ + cmpl $0, %edx + jnz 1f + addl $8, %esp + popl %esi + movl %ebp, %esp + popl %ebp + ret + .p2align 2 + + /* + * If we are in the child (new thread), then + * set-up the call to the internal subroutine. If it + * returns, then call __exit. + */ +1: + movl %esi,%esp + popl %eax + call *%eax + addl $12, %esp + + /* + * Exit system call + */ + pushl %eax +#ifdef SYS_exit + pushl $SYS_exit +#else + pushl $SYS_sys_exit +#endif + KERNCALL + + /* + * Branch here if the thread creation fails: + */ +2: + PIC_PROLOGUE + jmp PIC_PLT(HIDENAME(cerror)) |