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-rw-r--r--libc/sysdeps/linux/i386/clone.S87
1 files changed, 87 insertions, 0 deletions
diff --git a/libc/sysdeps/linux/i386/clone.S b/libc/sysdeps/linux/i386/clone.S
new file mode 100644
index 000000000..7a2025b53
--- /dev/null
+++ b/libc/sysdeps/linux/i386/clone.S
@@ -0,0 +1,87 @@
+/* Copyright (C) 1996, 1997, 1998, 1999 Free Software Foundation, Inc.
+ This file is part of the GNU C Library.
+ 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., 59 Temple Place - Suite 330,
+ Boston, MA 02111-1307, 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>
+#define _ERRNO_H 1
+#include <bits/errno.h>
+#include <asm-syntax.h>
+
+/* int clone(int (*fn)(void *arg), void *child_stack, int flags, void *arg); */
+
+ .text
+ENTRY(__clone)
+ /* Sanity check arguments. */
+ movl $-EINVAL,%eax
+ movl 4(%esp),%ecx /* no NULL function pointers */
+#ifdef PIC
+ jecxz SYSCALL_ERROR_LABEL
+#else
+ testl %ecx,%ecx
+ jz SYSCALL_ERROR_LABEL
+#endif
+ movl 8(%esp),%ecx /* no NULL stack pointers */
+#ifdef PIC
+ jecxz SYSCALL_ERROR_LABEL
+#else
+ testl %ecx,%ecx
+ jz SYSCALL_ERROR_LABEL
+#endif
+
+ /* Insert the argument onto the new stack. */
+ subl $8,%ecx
+ movl 16(%esp),%eax /* no negative argument counts */
+ movl %eax,4(%ecx)
+
+ /* 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_LABEL
+ jz thread_start
+
+L(pseudo_end):
+ ret
+
+thread_start:
+ subl %ebp,%ebp /* terminate the stack frame */
+ call *%ebx
+#ifdef PIC
+ call L(here)
+L(here):
+ popl %ebx
+ addl $_GLOBAL_OFFSET_TABLE_+[.-L(here)], %ebx
+#endif
+ pushl %eax
+ call JUMPTARGET (_exit)
+
+PSEUDO_END (__clone)
+
+weak_alias (__clone, clone)