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Filename : sysc_waitpid.stp
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# waitpid ____________________________________________________
#
# (waitpid is usually implemented via wait4 but not always)
# SYSCALL_DEFINE3(waitpid, pid_t, pid, int __user *, stat_addr, int, options)
#

@define _SYSCALL_WAITPID_NAME
%(
	name = "waitpid"
%)

@define _SYSCALL_WAITPID_ARGSTR
%(
	argstr = sprintf("%d, %p, %s", pid, status_uaddr, options_str)
%)

@define _SYSCALL_WAITPID_REGARGS
%(
	pid = int_arg(1)
	status_uaddr = pointer_arg(2)
	options = int_arg(3)
	options_str = _wait4_opt_str(options)
%)

probe syscall.waitpid = dw_syscall.waitpid !, nd_syscall.waitpid ? {}
probe syscall.waitpid.return = dw_syscall.waitpid.return !,
                               nd_syscall.waitpid.return ? {}

# dw_waitpid _____________________________________________________

probe dw_syscall.waitpid = kernel.function("sys_waitpid").call ?,
	kernel.function("sys32_waitpid").call ?,
	kernel.function("compat_sys_x86_waitpid").call ?
{
	@_SYSCALL_WAITPID_NAME
	pid = __int32($pid)
	status_uaddr = $stat_addr
	options = __int32($options)
	options_str = _wait4_opt_str(options)
	@_SYSCALL_WAITPID_ARGSTR
}
probe dw_syscall.waitpid.return = kernel.function("sys_waitpid").return ?,
	kernel.function("sys32_waitpid").return ?,
	kernel.function("compat_sys_x86_waitpid").return ?
{
	@_SYSCALL_WAITPID_NAME
	@SYSC_RETVALSTR($return)
}

# nd_waitpid _____________________________________________________

probe nd_syscall.waitpid = nd1_syscall.waitpid!, nd2_syscall.waitpid!, tp_syscall.waitpid
  { }

probe nd1_syscall.waitpid = kprobe.function("sys_waitpid") ?,
	kprobe.function("sys32_waitpid").call ?,
	kprobe.function("compat_sys_x86_waitpid") ?
{
	@_SYSCALL_WAITPID_NAME
	asmlinkage()
	@_SYSCALL_WAITPID_REGARGS
	@_SYSCALL_WAITPID_ARGSTR
}

/* kernel 4.17+ */
probe nd2_syscall.waitpid = kprobe.function(@arch_syscall_prefix "sys_waitpid") ?
{
	__set_syscall_pt_regs(pointer_arg(1))
	@_SYSCALL_WAITPID_NAME
	@_SYSCALL_WAITPID_REGARGS
	@_SYSCALL_WAITPID_ARGSTR
}

/* kernel 3.5+, but undesirable because it affects all syscalls */
probe tp_syscall.waitpid = kernel.trace("sys_enter")
{
	__set_syscall_pt_regs($regs)
	@__syscall_compat_gate(@const("__NR_waitpid"), @const("__NR_compat_waitpid"))
	@_SYSCALL_WAITPID_NAME
	@_SYSCALL_WAITPID_REGARGS
	@_SYSCALL_WAITPID_ARGSTR
}

probe nd_syscall.waitpid.return = nd1_syscall.waitpid.return!, nd2_syscall.waitpid.return!, tp_syscall.waitpid.return
  { }

probe nd1_syscall.waitpid.return = kprobe.function("sys_waitpid").return ?,
	kprobe.function("sys32_waitpid").return ?,
	kprobe.function("compat_sys_x86_waitpid").return ?
{
	@_SYSCALL_WAITPID_NAME
	@SYSC_RETVALSTR(returnval())
}

/* kernel 4.17+ */
probe nd2_syscall.waitpid.return = kprobe.function(@arch_syscall_prefix "sys_waitpid").return ?
{
	@_SYSCALL_WAITPID_NAME
	@SYSC_RETVALSTR(returnval())
}

/* kernel 3.5+, but undesirable because it affects all syscalls */
probe tp_syscall.waitpid.return = kernel.trace("sys_exit")
{
	__set_syscall_pt_regs($regs)
	@__syscall_compat_gate(@const("__NR_waitpid"), @const("__NR_compat_waitpid"))
	@_SYSCALL_WAITPID_NAME
	@SYSC_RETVALSTR($ret)
}