# truncate _______________________________________________________
#
# asmlinkage long sys32_truncate64(const char __user *filename,
#				   unsigned long offset_low,
#				   unsigned long offset_high)
# COMPAT_SYSCALL_DEFINE3(x86_truncate64, const char __user *, filename,
#			 unsigned long, offset_low, unsigned long, offset_high)
#

@define _SYSCALL_COMPAT_TRUNCATE64_NAME
%(
	name = "truncate"
%)

@define _SYSCALL_COMPAT_TRUNCATE64_ARGSTR
%(
	argstr = sprintf("%s, %d", path, length)
%)

@define _SYSCALL_COMPAT_TRUNCATE64_REGARGS
%(
	path_uaddr = pointer_arg(1)
	path = user_string_quoted(path_uaddr)
        length = ((uint_arg(3) << 32) | uint_arg(2))
%)

probe syscall.compat_truncate64 = dw_syscall.compat_truncate64 !,
                                  nd_syscall.compat_truncate64 ? {}
probe syscall.compat_truncate64.return = dw_syscall.compat_truncate64.return !,
                                         nd_syscall.compat_truncate64.return ? {}

# dw_compat_truncate64 _____________________________________________________

probe dw_syscall.compat_truncate64 =
	kernel.function("sys32_truncate64").call ?,
	kernel.function("compat_sys_x86_truncate64").call ?
{
        @_SYSCALL_COMPAT_TRUNCATE64_NAME
	path_uaddr = $filename
	path = user_string_quoted(path_uaddr)
        length = (($offset_high << 32) | $offset_low)
	@_SYSCALL_COMPAT_TRUNCATE64_ARGSTR
}
probe dw_syscall.compat_truncate64.return =
	kernel.function("sys32_truncate64").return ?,
	kernel.function("compat_sys_x86_truncate64").return ?
{
	@_SYSCALL_COMPAT_TRUNCATE64_NAME
	@SYSC_RETVALSTR($return)
}

# nd_compat_truncate64 _____________________________________________________

probe nd_syscall.compat_truncate64 = nd1_syscall.compat_truncate64!, nd2_syscall.compat_truncate64!, tp_syscall.compat_truncate64
  { }

probe nd1_syscall.compat_truncate64 =
	kprobe.function("sys32_truncate64") ?,
	kprobe.function("compat_sys_x86_truncate64") ?
{
	asmlinkage()
        @_SYSCALL_COMPAT_TRUNCATE64_NAME
	@_SYSCALL_COMPAT_TRUNCATE64_REGARGS
	@_SYSCALL_COMPAT_TRUNCATE64_ARGSTR
}

/* kernel 4.17+ */
probe nd2_syscall.compat_truncate64 =
	kprobe.function(@arch_syscall_prefix "compat_sys_x86_truncate64") ?
{
	__set_syscall_pt_regs(pointer_arg(1))
	@_SYSCALL_COMPAT_TRUNCATE64_NAME
	@_SYSCALL_COMPAT_TRUNCATE64_REGARGS
	@_SYSCALL_COMPAT_TRUNCATE64_ARGSTR
}

/* kernel 3.5+, but undesirable because it affects all syscalls */
probe tp_syscall.compat_truncate64 = kernel.trace("sys_enter")
{
	__set_syscall_pt_regs($regs)
	@__compat_syscall_gate(@const("__NR_ia32_truncate64"))
	@_SYSCALL_COMPAT_TRUNCATE64_NAME
	@_SYSCALL_COMPAT_TRUNCATE64_REGARGS
	@_SYSCALL_COMPAT_TRUNCATE64_ARGSTR
}

probe nd_syscall.compat_truncate64.return = nd1_syscall.compat_truncate64.return!, nd2_syscall.compat_truncate64.return!, tp_syscall.compat_truncate64.return
  { }

probe nd1_syscall.compat_truncate64.return =
	kprobe.function("sys32_truncate64").return ?,
	kprobe.function("compat_sys_x86_truncate64").return ?
{
	@_SYSCALL_COMPAT_TRUNCATE64_NAME
	@SYSC_RETVALSTR(returnval())
}

/* kernel 4.17+ */
probe nd2_syscall.compat_truncate64.return =
	kprobe.function(@arch_syscall_prefix "compat_sys_x86_truncate64").return ?
{
	@_SYSCALL_COMPAT_TRUNCATE64_NAME
	@SYSC_RETVALSTR(returnval())
}

/* kernel 3.5+, but undesirable because it affects all syscalls */
probe tp_syscall.compat_truncate64.return = kernel.trace("sys_exit")
{
	__set_syscall_pt_regs($regs)
	@__compat_syscall_gate(@const("__NR_ia32_truncate64"))
	@_SYSCALL_COMPAT_TRUNCATE64_NAME
	@SYSC_RETVALSTR($ret)
}