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Filename : sysc_fchmodat.stp
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# fchmodat ___________________________________________________
# new function with 2.6.16
# long sys_fchmodat(int dfd, const char __user *filename,
#	mode_t mode)

@define _SYSCALL_FCHMODAT_NAME
%(
	name = "fchmodat"
%)

@define _SYSCALL_FCHMODAT_ARGSTR
%(
	argstr = sprintf("%s, %s, %#o", dirfd_str, pathname, mode)
%)

@define _SYSCALL_FCHMODAT_REGARGS
%(
	dirfd = int_arg(1)
	dirfd_str = _dfd_str(dirfd)
	pathname = user_string_quoted(pointer_arg(2))
	mode = uint_arg(3)
%)

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

# dw_fchmodat _____________________________________________________

probe dw_syscall.fchmodat = kernel.function("sys_fchmodat").call ?
{
	@__syscall_compat_gate(@const("__NR_fchmodat"),
			       @const("__NR_compat_fchmodat"))
	@_SYSCALL_FCHMODAT_NAME
	dirfd = __int32($dfd)
	dirfd_str = _dfd_str(__int32($dfd))
	pathname = user_string_quoted($filename)
%( arch == "i386" %?
	# Why @cast() here? Even though the user passes an unsigned
	# int (32-bits), some kernels (2.6.32-431.el6.i686) get an
	# unsigned short (16-bits).
	mode = @uint_cast(&$mode)
%:
	mode = __uint32($mode)
%)
	@_SYSCALL_FCHMODAT_ARGSTR
}
probe dw_syscall.fchmodat.return = kernel.function("sys_fchmodat").return ?
{
	@__syscall_compat_gate(@const("__NR_fchmodat"),
			       @const("__NR_compat_fchmodat"))
	@_SYSCALL_FCHMODAT_NAME
	@SYSC_RETVALSTR($return)
}

# nd_fchmodat _____________________________________________________

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

probe nd1_syscall.fchmodat = kprobe.function("sys_fchmodat") ?
{
	@__syscall_compat_gate(@const("__NR_fchmodat"),
			       @const("__NR_compat_fchmodat"))
	@_SYSCALL_FCHMODAT_NAME
	asmlinkage()
	@_SYSCALL_FCHMODAT_REGARGS
	@_SYSCALL_FCHMODAT_ARGSTR
}

/* kernel 4.17+ */
probe nd2_syscall.fchmodat = kprobe.function(@arch_syscall_prefix "sys_fchmodat") ?
{
	__set_syscall_pt_regs(pointer_arg(1))
	@_SYSCALL_FCHMODAT_NAME
	@_SYSCALL_FCHMODAT_REGARGS
	@_SYSCALL_FCHMODAT_ARGSTR
}

/* kernel 3.5+, but undesirable because it affects all syscalls */
probe tp_syscall.fchmodat = kernel.trace("sys_enter")
{
	__set_syscall_pt_regs($regs)
	@__syscall_compat_gate(@const("__NR_fchmodat"), @const("__NR_compat_fchmodat"))
	@_SYSCALL_FCHMODAT_NAME
	@_SYSCALL_FCHMODAT_REGARGS
	@_SYSCALL_FCHMODAT_ARGSTR
}

probe nd_syscall.fchmodat.return = nd1_syscall.fchmodat.return!, nd2_syscall.fchmodat.return!, tp_syscall.fchmodat.return
  { }
  
probe nd1_syscall.fchmodat.return = kprobe.function("sys_fchmodat").return ?
{
	@__syscall_compat_gate(@const("__NR_fchmodat"),
			       @const("__NR_compat_fchmodat"))
	@_SYSCALL_FCHMODAT_NAME
	@SYSC_RETVALSTR(returnval())
}

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