1/* Copyright (C) 1996, 1997, 1998, 1999, 2000 Free Software Foundation, Inc. 2 This file is part of the GNU C Library. 3 Contributed by Richard Henderson (rth@tamu.edu) 4 5 The GNU C Library is free software; you can redistribute it and/or 6 modify it under the terms of the GNU Lesser General Public 7 License as published by the Free Software Foundation; either 8 version 2.1 of the License, or (at your option) any later version. 9 10 The GNU C Library is distributed in the hope that it will be useful, 11 but WITHOUT ANY WARRANTY; without even the implied warranty of 12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 13 Lesser General Public License for more details. 14 15 You should have received a copy of the GNU Lesser General Public 16 License along with the GNU C Library; if not, write to the Free 17 Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 18 02111-1307 USA. */ 19 20/* clone() is even more special than fork() as it mucks with stacks 21 and invokes a function in the right context after its all over. */ 22 23#include <sysdep.h> 24#define _ERRNO_H 1 25#include <bits/errno.h> 26#include <asm/unistd.h> 27#include <bp-sym.h> 28#include <bp-asm.h> 29 30/* int clone(int (*fn)(void *arg), void *child_stack, int flags, void *arg); */ 31 32#define PARMS LINKAGE /* no space for saved regs */ 33#define FUNC PARMS 34#define STACK FUNC+4 35#define FLAGS STACK+PTR_SIZE 36#define ARG FLAGS+4 37 38 .text 39ENTRY (BP_SYM (__clone)) 40 /* Sanity check arguments. */ 41 movl $-EINVAL,%eax 42 movl FUNC(%esp),%ecx /* no NULL function pointers */ 43#ifdef PIC 44 jecxz SYSCALL_ERROR_LABEL 45#else 46 testl %ecx,%ecx 47 jz SYSCALL_ERROR_LABEL 48#endif 49 movl STACK(%esp),%ecx /* no NULL stack pointers */ 50#ifdef PIC 51 jecxz SYSCALL_ERROR_LABEL 52#else 53 testl %ecx,%ecx 54 jz SYSCALL_ERROR_LABEL 55#endif 56 57 /* Insert the argument onto the new stack. */ 58 subl $8,%ecx 59 movl ARG(%esp),%eax /* no negative argument counts */ 60 movl %eax,4(%ecx) 61 62 /* Save the function pointer as the zeroth argument. 63 It will be popped off in the child in the ebx frobbing below. */ 64 movl FUNC(%esp),%eax 65 movl %eax,0(%ecx) 66 67 /* Do the system call */ 68 pushl %ebx 69 movl FLAGS+4(%esp),%ebx 70 movl $SYS_ify(clone),%eax 71 int $0x80 72 popl %ebx 73 74 test %eax,%eax 75 jl SYSCALL_ERROR_LABEL 76 jz thread_start 77 78L(pseudo_end): 79 ret 80 81thread_start: 82 subl %ebp,%ebp /* terminate the stack frame */ 83 call *%ebx 84#ifdef PIC 85 call L(here) 86L(here): 87 popl %ebx 88 addl $_GLOBAL_OFFSET_TABLE_+[.-L(here)], %ebx 89#endif 90 pushl %eax 91 call JUMPTARGET (_exit) 92 93PSEUDO_END (BP_SYM (__clone)) 94 95weak_alias (BP_SYM (__clone), BP_SYM (clone)) 96