diff options
Diffstat (limited to 'sysdeps/unix/sysv/linux/i386')
| -rw-r--r-- | sysdeps/unix/sysv/linux/i386/clone.S | 80 |
1 files changed, 80 insertions, 0 deletions
diff --git a/sysdeps/unix/sysv/linux/i386/clone.S b/sysdeps/unix/sysv/linux/i386/clone.S new file mode 100644 index 0000000000..02f561927e --- /dev/null +++ b/sysdeps/unix/sysv/linux/i386/clone.S @@ -0,0 +1,80 @@ +/* Copyright (C) 1996 Free Software Foundation, Inc. + Contributed by Richard Henderson (rth@tamu.edu) + +The GNU C Library is free software; you can redistribute it and/or +modify it under the terms of the GNU Library General Public License as +published by the Free Software Foundation; either version 2 of the +License, or (at your option) any later version. + +The GNU C Library is distributed in the hope that it will be useful, +but WITHOUT ANY WARRANTY; without even the implied warranty of +MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU +Library General Public License for more details. + +You should have received a copy of the GNU Library General Public +License along with the GNU C Library; see the file COPYING.LIB. If +not, write to the Free Software Foundation, Inc., 675 Mass Ave, +Cambridge, MA 02139, USA. */ + +/* clone() is even more special than fork() as it mucks with stacks + and invokes a function in the right context after its all over. */ + +#include <sysdep.h> +#include <errnos.h> + +/* int clone(int (*fn)(), void *child_stack, int flags, int nargs, ...) */ + + .text +ENTRY(__clone) + /* Sanity check arguments. */ + movl $-EINVAL,%eax + movl 4(%esp),%ecx /* no NULL function pointers */ + testl %ecx,%ecx + jz syscall_error + movl 8(%esp),%ecx /* no NULL stack pointers */ + testl %ecx,%ecx + jz syscall_error + movl 16(%esp),%edx /* no negative argument counts */ + testl %edx,%edx + js syscall_error + + /* Allocate space on the new stack and copy args over */ + movl %edx,%eax + negl %eax + lea -4(%ecx,%eax,4),%ecx + jz 2f +1: movl 16(%esp,%edx,4),%eax + movl %eax,0(%ecx,%edx,4) + dec %edx + jnz 1b +2: + /* Save the function pointer as the zeroth argument. + It will be popped off in the child in the ebx frobbing below. */ + movl 4(%esp),%eax + movl %eax,0(%ecx) + + /* Do the system call */ + pushl %ebx + movl 16(%esp),%ebx + movl $SYS_ify(clone),%eax + int $0x80 + popl %ebx + + test %eax,%eax + jl syscall_error + jz thread_start + + ret + + SYSCALL_ERROR_HANDLER + +thread_start: + subl %ebp,%ebp /* terminate the stack frame */ + call *%ebx +#ifdef PIC + call _exit@PLT +#else + call _exit +#endif + +weak_alias(__clone, clone) |