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Filename : sysc_umask.stp
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# umask ______________________________________________________
# long sys_umask(int mask)
#

@define _SYSCALL_UMASK_NAME
%(
	name = "umask"
%)

@define _SYSCALL_UMASK_ARGSTR
%(
	argstr = sprintf("%#o", mask)
%)

@define _SYSCALL_UMASK_REGARGS
%(
	mask = uint_arg(1)
%)

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

# dw_umask _____________________________________________________

probe dw_syscall.umask = kernel.function("sys_umask").call
{
	@_SYSCALL_UMASK_NAME
	mask = __uint32($mask)
	@_SYSCALL_UMASK_ARGSTR
}
probe dw_syscall.umask.return = kernel.function("sys_umask").return
{
	@_SYSCALL_UMASK_NAME
	@SYSC_RETVALSTR3($return)
}

# nd_umask _____________________________________________________

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

probe nd1_syscall.umask = kprobe.function("sys_umask") ?
{
	@_SYSCALL_UMASK_NAME
	asmlinkage()
	@_SYSCALL_UMASK_REGARGS
	@_SYSCALL_UMASK_ARGSTR
}

/* kernel 4.17+ */
probe nd2_syscall.umask = kprobe.function(@arch_syscall_prefix "sys_umask") ?
{
	__set_syscall_pt_regs(pointer_arg(1))
	@_SYSCALL_UMASK_NAME
	@_SYSCALL_UMASK_REGARGS
	@_SYSCALL_UMASK_ARGSTR
}

/* kernel 3.5+, but undesirable because it affects all syscalls */
probe tp_syscall.umask = kernel.trace("sys_enter")
{
	__set_syscall_pt_regs($regs)
	@__syscall_compat_gate(@const("__NR_umask"), @const("__NR_compat_umask"))
	@_SYSCALL_UMASK_NAME
	@_SYSCALL_UMASK_REGARGS
	@_SYSCALL_UMASK_ARGSTR
}

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

probe nd1_syscall.umask.return = kprobe.function("sys_umask").return ?
{
	@_SYSCALL_UMASK_NAME
	@SYSC_RETVALSTR3(returnval())
}

/* kernel 4.17+ */
probe nd2_syscall.umask.return = kprobe.function(@arch_syscall_prefix "sys_umask").return ?
{
	@_SYSCALL_UMASK_NAME
	@SYSC_RETVALSTR3(returnval())
}

/* kernel 3.5+, but undesirable because it affects all syscalls */
probe tp_syscall.umask.return = kernel.trace("sys_exit")
{
	__set_syscall_pt_regs($regs)
	@__syscall_compat_gate(@const("__NR_umask"), @const("__NR_compat_umask"))
	@_SYSCALL_UMASK_NAME
	@SYSC_RETVALSTR3($ret)
}