diff options
Diffstat (limited to 'libc/sysdeps/linux')
| -rw-r--r-- | libc/sysdeps/linux/x86_64/clone.S | 116 | ||||
| -rw-r--r-- | libc/sysdeps/linux/x86_64/vfork.S | 53 |
2 files changed, 169 insertions, 0 deletions
diff --git a/libc/sysdeps/linux/x86_64/clone.S b/libc/sysdeps/linux/x86_64/clone.S new file mode 100644 index 000000000..9d244d018 --- /dev/null +++ b/libc/sysdeps/linux/x86_64/clone.S @@ -0,0 +1,116 @@ +/* Copyright (C) 2001, 2002, 2003, 2004 Free Software Foundation, Inc. + This file is part of the GNU C Library. + + The GNU C Library is free software; you can redistribute it and/or + modify it under the terms of the GNU Lesser General Public + License as published by the Free Software Foundation; either + version 2.1 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 + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public + License along with the GNU C Library; 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. */ + +#define _ERRNO_H 1 +#include <bits/errno.h> + +#define CLONE_VM 0x00000100 +#define CLONE_THREAD 0x00010000 + +/* The userland implementation is: + int clone (int (*fn)(void *arg), void *child_stack, int flags, void *arg), + the kernel entry is: + int clone (long flags, void *child_stack). + + The parameters are passed in register and on the stack from userland: + rdi: fn + rsi: child_stack + rdx: flags + rcx: arg + r8d: TID field in parent + r9d: thread pointer +%esp+8: TID field in child + + The kernel expects: + rax: system call number + rdi: flags + rsi: child_stack + rdx: TID field in parent + r10: TID field in child + r8: thread pointer */ + + + .text +.globl __clone; +.type __clone,@function +.align 4; +__clone: + /* Sanity check arguments. */ + movq $-EINVAL,%rax + testq %rdi,%rdi /* no NULL function pointers */ + jz __syscall_error + testq %rsi,%rsi /* no NULL stack pointers */ + jz __syscall_error + + /* Insert the argument onto the new stack. */ + subq $16,%rsi + movq %rcx,8(%rsi) + + /* Save the function pointer. It will be popped off in the + child in the ebx frobbing below. */ + movq %rdi,0(%rsi) + + /* Do the system call. */ + movq %rdx, %rdi + movq %r8, %rdx + movq %r9, %r8 + movq 8(%rsp), %r10 + movq $__NR_clone,%rax + + syscall + + testq %rax,%rax + jl __syscall_error + jz L(thread_start) + +L(pseudo_end): + ret + +L(thread_start): + /* Clear the frame pointer. The ABI suggests this be done, to mark + the outermost frame obviously. */ + xorq %rbp, %rbp + +#ifdef RESET_PID + testq $CLONE_THREAD, %rdi + jne 1f + testq $CLONE_VM, %rdi + movl $-1, %eax + jne 2f + movq __NR_getpid, %rax + syscall +2: movl %eax, %fs:PID + movl %eax, %fs:TID +1: +#endif + + /* Set up arguments for the function call. */ + popq %rax /* Function to call. */ + popq %rdi /* Argument. */ + call *%rax + /* Call exit with return value from function call. */ + movq %rax, %rdi + call HIDDEN_JUMPTARGET (_exit) + + cfi_startproc; +PSEUDO_END (BP_SYM (__clone)) + +weak_alias (BP_SYM (__clone), BP_SYM (clone)) diff --git a/libc/sysdeps/linux/x86_64/vfork.S b/libc/sysdeps/linux/x86_64/vfork.S new file mode 100644 index 000000000..072a3a0a8 --- /dev/null +++ b/libc/sysdeps/linux/x86_64/vfork.S @@ -0,0 +1,53 @@ +/* Copyright (C) 2001, 2002, 2004 Free Software Foundation, Inc. + This file is part of the GNU C Library. + + The GNU C Library is free software; you can redistribute it and/or + modify it under the terms of the GNU Lesser General Public + License as published by the Free Software Foundation; either + version 2.1 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 + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public + License along with the GNU C Library; if not, write to the Free + Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA + 02111-1307 USA. */ + +#define _ERRNO_H 1 +#include <bits/errno.h> + +/* Clone the calling process, but without copying the whole address space. + The calling process is suspended until the new process exits or is + replaced by a call to `execve'. Return -1 for errors, 0 to the new process, + and the process ID of the new process to the old process. */ + +.globl __vfork; +.type __vfork,@function; +.align 16; +__vfork: + + /* Pop the return PC value into RDI. We need a register that + is preserved by the syscall and that we're allowed to destroy. */ + popq %rdi + + /* Stuff the syscall number in RAX and enter into the kernel. */ + movl $__NR_vfork, %eax + syscall + + /* Push back the return PC. */ + pushq %rdi + + cmpl $-4095, %eax + jae __syscall_error /* Branch forward if it failed. */ + + /* Normal return. */ + ret + +__syscall_error: + /* TODO: implement this ! :D */ + +.size __vfork,.Lsize-__vfork +.weak vfork ; vfork = __vfork |