^^&&^^

Edit File: sysc_linkat.stp

# linkat _____________________________________________________
# new function with 2.6.16
# long sys_linkat(int olddfd, const char __user *oldname,
#	int newdfd, const char __user *newname, int flags)

@define _SYSCALL_LINKAT_NAME
%(
	name = "linkat"
%)

@define _SYSCALL_LINKAT_ARGSTR
%(
	argstr = sprintf("%s, %s, %s, %s, %s", olddirfd_str, oldpath,
	                 newdirfd_str, newpath, flags_str)
%)

@define _SYSCALL_LINKAT_REGARGS
%(
	olddirfd = int_arg(1)
	olddirfd_str = _dfd_str(olddirfd)
	oldpath = user_string_quoted(pointer_arg(2))
	newdirfd = int_arg(3)
	newdirfd_str = _dfd_str(newdirfd)
	newpath = user_string_quoted(pointer_arg(4))
	flags = int_arg(5)
	flags_str = _at_flag_str(flags)
%)

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

# dw_linkat _____________________________________________________

probe dw_syscall.linkat = kernel.function("sys_linkat").call ?
{
	@__syscall_compat_gate(@const("__NR_linkat"), @const("__NR_compat_linkat"))
	@_SYSCALL_LINKAT_NAME
	olddirfd = __int32($olddfd)
	olddirfd_str = _dfd_str(__int32($olddfd))
	oldpath = user_string_quoted($oldname)
	newdirfd = __int32($newdfd)
	newdirfd_str = _dfd_str(__int32($newdfd))
	newpath = user_string_quoted($newname)
	flags = __int32($flags)
	flags_str = _at_flag_str(__int32($flags))
	@_SYSCALL_LINKAT_ARGSTR
}
probe dw_syscall.linkat.return = kernel.function("sys_linkat").return ?
{
	@__syscall_compat_gate(@const("__NR_linkat"), @const("__NR_compat_linkat"))
	@_SYSCALL_LINKAT_NAME
	@SYSC_RETVALSTR($return)
}

# nd_linkat _____________________________________________________

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

probe nd1_syscall.linkat = kprobe.function("sys_linkat") ?
{
	@__syscall_compat_gate(@const("__NR_linkat"), @const("__NR_compat_linkat"))
	@_SYSCALL_LINKAT_NAME
	asmlinkage()
	@_SYSCALL_LINKAT_REGARGS
	@_SYSCALL_LINKAT_ARGSTR
}

/* kernel 4.17+ */
probe nd2_syscall.linkat = kprobe.function(@arch_syscall_prefix "sys_linkat") ?
{
	__set_syscall_pt_regs(pointer_arg(1))
	@_SYSCALL_LINKAT_NAME
	@_SYSCALL_LINKAT_REGARGS
	@_SYSCALL_LINKAT_ARGSTR
}

/* kernel 3.5+, but undesirable because it affects all syscalls */
probe tp_syscall.linkat = kernel.trace("sys_enter")
{
	__set_syscall_pt_regs($regs)
	@__syscall_compat_gate(@const("__NR_linkat"), @const("__NR_compat_linkat"))
	@_SYSCALL_LINKAT_NAME
	@_SYSCALL_LINKAT_REGARGS
	@_SYSCALL_LINKAT_ARGSTR
}

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

probe nd1_syscall.linkat.return = kprobe.function("sys_linkat").return ?
{
	@__syscall_compat_gate(@const("__NR_linkat"), @const("__NR_compat_linkat"))
	@_SYSCALL_LINKAT_NAME
	@SYSC_RETVALSTR(returnval())
}

/* kernel 4.17+ */
probe nd2_syscall.linkat.return = kprobe.function(@arch_syscall_prefix "sys_linkat").return ?
{
	@_SYSCALL_LINKAT_NAME
	@SYSC_RETVALSTR(returnval())
}
 
/* kernel 3.5+, but undesirable because it affects all syscalls */
probe tp_syscall.linkat.return = kernel.trace("sys_exit")
{
	__set_syscall_pt_regs($regs)
	@__syscall_compat_gate(@const("__NR_linkat"), @const("__NR_compat_linkat"))
	@_SYSCALL_LINKAT_NAME
	@SYSC_RETVALSTR($ret)
}