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Filename : sysc_clone.stp
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# clone ______________________________________________________
#
# The sys_clone() call was in arch-specific code (sometimes assembly
# code), especially in older kernels. Its args varied dramatically,
# from full args to getting nothing but registers. To get around this,
# we'll just probe do_fork(). The fork()/vfork()/clone() syscalls are
# just wrappers around do_fork().  We'll reject all probe hits that
# aren't really clone syscalls (such as calls to sys_fork(),
# sys_vfork(), and the kernel's internal use of do_fork()). Kernel
# commit 3033f14ab78c32 renamed 'do_fork' to '_do_fork'.
#
# For ia64, this is complicated by the fact that it has a clone2
# syscall.
#

probe syscall.clone = dw_syscall.clone !, nd_syscall.clone {}
probe syscall.clone.return = dw_syscall.clone.return !, nd_syscall.clone.return {}

# dw_clone _____________________________________________________

probe dw_syscall.clone = kernel.function("_do_fork").call !,
	kernel.function("do_fork").call
{
%( arch != "ia64" %?
	@__syscall_compat_gate(@const("__NR_clone"), @const("__NR_compat_clone"))
	name = "clone"
%:
	@__syscall_gate2(@const("__NR_clone"), @const("__NR_clone2"))
	// This is a bit gross. We're depending on @__syscall_gate2()
	// to set '__nr' for us. If its implementation changes, this will
	// need to change.
	if (__nr == @const("__NR_clone"))
		name = "clone"
	else {
		name = "clone2"
		stack_size = $stack_size
	}	
%)
	clone_flags = $clone_flags
	stack_start = $stack_start
	parent_tid_uaddr = $parent_tidptr
	child_tid_uaddr = $child_tidptr

%( arch != "ia64" %?
	argstr = sprintf("%s, %p, %p, %p", __fork_flags($clone_flags),
	                 $stack_start, $parent_tidptr, $child_tidptr)
%:
	if (__nr == @const("__NR_clone"))
		argstr = sprintf("%s, %p, %p, %p", __fork_flags($clone_flags),
		                 $stack_start, $parent_tidptr, $child_tidptr)
	else
		argstr = sprintf("%s, %p, %p, %p, %p",
		                 __fork_flags($clone_flags), $stack_start,
				 $stack_size, $parent_tidptr, $child_tidptr)
%)
}
probe dw_syscall.clone.return = kernel.function("_do_fork").return !,
	kernel.function("do_fork").return
{
%( arch != "ia64" %?
	@__syscall_compat_gate(@const("__NR_clone"), @const("__NR_compat_clone"))
	name = "clone"
%:
	@__syscall_gate2(@const("__NR_clone"), @const("__NR_clone2"))
	// This is a bit gross. We're depending on @__syscall_gate2()
	// to set '__nr' for us. If its implementation changes, this will
	// need to change.
	if (__nr == @const("__NR_clone"))
		name = "clone"
	else
		name = "clone2"
%)
	@SYSC_RETVALSTR($return)
}

# nd_clone _____________________________________________________

probe nd_syscall.clone = nd1_syscall.clone!, tp_syscall.clone
  { }

probe nd1_syscall.clone = kprobe.function("_do_fork").call !,
	kprobe.function("do_fork").call
{
%( arch != "ia64" %?
	@__syscall_compat_gate(@const("__NR_clone"), @const("__NR_compat_clone"))
	name = "clone"
%:
	@__syscall_gate2(@const("__NR_clone"), @const("__NR_clone2"))
	// This is a bit gross. We're depending on @__syscall_gate2()
	// to set '__nr' for us. If its implementation changes, this will
	// need to change.
	if (__nr == @const("__NR_clone"))
		name = "clone"
	else {
		name = "clone2"
%(kernel_v >= "3.8.0" %?
		stack_size = ulong_arg(3)
%:
		stack_size = ulong_arg(4)
%)
	}	
%)

	clone_flags = long_arg(1)
	stack_start = pointer_arg(2)
%(kernel_v >= "3.8.0" %?
	parent_tid_uaddr = pointer_arg(4)
	child_tid_uaddr = pointer_arg(5)
%:
	parent_tid_uaddr = pointer_arg(5)
	child_tid_uaddr = pointer_arg(6)
%)

%( arch != "ia64" %?
	argstr = sprintf("%s, %p, %p, %p", __fork_flags(clone_flags),
	                 stack_start, parent_tid_uaddr, child_tid_uaddr)
%:
	if (__nr == @const("__NR_clone"))
		argstr = sprintf("%s, %p, %p, %p", __fork_flags(clone_flags),
		                 stack_start, parent_tid_uaddr, child_tid_uaddr)
	else			
		argstr = sprintf("%s, %p, %p, %p, %p",
		                 __fork_flags(clone_flags), stack_start,
				 stack_size, parent_tid_uaddr, child_tid_uaddr)
%)
}

probe tp_syscall.clone = kernel.trace("sys_enter")
{
	__set_syscall_pt_regs($regs)
%( arch != "ia64" %?
	@__syscall_compat_gate(@const("__NR_clone"), @const("__NR_compat_clone"))
	name = "clone"
%:
	@__syscall_gate2(@const("__NR_clone"), @const("__NR_clone2"))
	// This is a bit gross. We're depending on @__syscall_gate2()
	// to set '__nr' for us. If its implementation changes, this will
	// need to change.
	if (__nr == @const("__NR_clone"))
		name = "clone"
	else {
		name = "clone2"
		stack_size = ulong_arg(3)
	}
%)

	clone_flags = long_arg(@SYSC_CLONE_CLONE_FLAGS_ARGNO)
	stack_start = pointer_arg(@SYSC_CLONE_STACK_START_ARGNO)
	parent_tid_uaddr = pointer_arg(@SYSC_CLONE_PARENT_TID_UADDR_ARGNO)
	child_tid_uaddr = pointer_arg(@SYSC_CLONE_CHILD_TID_UADDR_ARGNO)

%( arch != "ia64" %?
	argstr = sprintf("%s, %p, %p, %p", __fork_flags(clone_flags),
	                 stack_start, parent_tid_uaddr, child_tid_uaddr)
%:
	if (__nr == @const("__NR_clone"))
		argstr = sprintf("%s, %p, %p, %p", __fork_flags(clone_flags),
		                 stack_start, parent_tid_uaddr, child_tid_uaddr)
	else
		argstr = sprintf("%s, %p, %p, %p, %p",
		                 __fork_flags(clone_flags), stack_start,
				 stack_size, parent_tid_uaddr, child_tid_uaddr)
%)
}

probe nd1_syscall.clone.return = kprobe.function("_do_fork").return !,
	kprobe.function("do_fork").return
{
%( arch != "ia64" %?
	@__syscall_compat_gate(@const("__NR_clone"), @const("__NR_compat_clone"))
	name = "clone"
%:
	@__syscall_gate2(@const("__NR_clone"), @const("__NR_clone2"))
	// This is a bit gross. We're depending on @__syscall_gate2()
	// to set '__nr' for us. If its implementation changes, this will
	// need to change.
	if (__nr == @const("__NR_clone"))
		name = "clone"
	else
		name = "clone2"
%)
	@SYSC_RETVALSTR(returnval())
}

probe tp_syscall.clone.return = kernel.trace("sys_exit")
{
	__set_syscall_pt_regs($regs)
%( arch != "ia64" %?
	@__syscall_compat_gate(@const("__NR_clone"), @const("__NR_compat_clone"))
	name = "clone"
%:
	@__syscall_gate2(@const("__NR_clone"), @const("__NR_clone2"))
	// This is a bit gross. We're depending on @__syscall_gate2()
	// to set '__nr' for us. If its implementation changes, this will
	// need to change.
	if (__nr == @const("__NR_clone"))
		name = "clone"
	else
		name = "clone2"
%)
	@SYSC_RETVALSTR($ret)
}