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Filename : sysc_chdir.stp
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# chdir ______________________________________________________
# long sys_chdir(const char __user * filename)

@define _SYSCALL_CHDIR_NAME
%(
	name = "chdir"
%)

@define _SYSCALL_CHDIR_ARGSTR
%(
	argstr = path
%)

@define _SYSCALL_CHDIR_REGARGS
%(
	path = user_string_quoted(pointer_arg(1))
%)

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

# dw_chdir _____________________________________________________

probe dw_syscall.chdir = kernel.function("sys_chdir").call
{
	@_SYSCALL_CHDIR_NAME
	path = user_string_quoted($filename)
	@_SYSCALL_CHDIR_ARGSTR
}
probe dw_syscall.chdir.return = kernel.function("sys_chdir").return
{
	@_SYSCALL_CHDIR_NAME
	@SYSC_RETVALSTR($return)
}

# nd_chdir _____________________________________________________

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

probe nd1_syscall.chdir = kprobe.function("sys_chdir") ?
{
	@_SYSCALL_CHDIR_NAME
	asmlinkage()
	@_SYSCALL_CHDIR_REGARGS
	@_SYSCALL_CHDIR_ARGSTR
}

/* kernel 4.17+ */
probe nd2_syscall.chdir = kprobe.function(@arch_syscall_prefix "sys_chdir")
{
	__set_syscall_pt_regs(pointer_arg(1))
	@_SYSCALL_CHDIR_NAME
	@_SYSCALL_CHDIR_REGARGS
	@_SYSCALL_CHDIR_ARGSTR
}

/* kernel 3.5+, but undesirable because it affects all syscalls */
probe tp_syscall.chdir = kernel.trace("sys_enter")
{
	__set_syscall_pt_regs($regs)
	@__syscall_compat_gate(@const("__NR_chdir"), @const("__NR_compat_chdir"))
	@_SYSCALL_CHDIR_NAME
	@_SYSCALL_CHDIR_REGARGS
	@_SYSCALL_CHDIR_ARGSTR
}

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

probe nd1_syscall.chdir.return = kprobe.function("sys_chdir").return ?
{
	@_SYSCALL_CHDIR_NAME
	@SYSC_RETVALSTR(returnval())
}

/* kernel 4.17+ */
probe nd2_syscall.chdir.return = kprobe.function(@arch_syscall_prefix "sys_chdir").return
{
	@_SYSCALL_CHDIR_NAME
	@SYSC_RETVALSTR(returnval())
}
 
/* kernel 3.5+, but undesirable because it affects all syscalls */
probe tp_syscall.chdir.return = kernel.trace("sys_exit")
{
	__set_syscall_pt_regs($regs)
	@__syscall_compat_gate(@const("__NR_chdir"), @const("__NR_compat_chdir"))
	@_SYSCALL_CHDIR_NAME
	@SYSC_RETVALSTR($ret)
}