[DTrace-devel] [PATCH] test: Fix use of syscall::execve:entry args[1][?]

[Kris Van Hees]

On Thu, Feb 15, 2024 at 05:42:42PM -0500, eugene.loh at oracle.com wrote:
> 
> Commit 82332371 ("proc: use a rawtp for the proc:::exit probe") included
> some test changes.  Specifically, it sought to use syscall::execve:entry
> probe arguments args[1][0] and args[1][1] to recognize "sleep 10000".
> The patch recognized that the argv pointers in question were in user
> space, requiring copyinstr() to access the strings.
> 
> But it's trickier than that.  The args[1][?] require two dereferencings,
> both in user space.  So a copyin() is required to access args[1] and
> then copyinstr() to access the args[1][?].
> 
> Fix the tests to use two layers of copyin*() to double dereference the
> args[1][?] strings.
> 
> Signed-off-by: Eugene Loh <eugene.loh at oracle.com>

Reviewed-by: Kris Van Hees <kris.van.hees at oracle.com>

> ---
>  test/unittest/proc/tst.exitkilled.sh | 6 ++++--
>  test/unittest/proc/tst.signal.sh     | 8 ++++++--
>  2 files changed, 10 insertions(+), 4 deletions(-)
> 
> diff --git a/test/unittest/proc/tst.exitkilled.sh b/test/unittest/proc/tst.exitkilled.sh
> index be9fc651..723dff88 100755
> --- a/test/unittest/proc/tst.exitkilled.sh
> +++ b/test/unittest/proc/tst.exitkilled.sh
> @@ -12,8 +12,10 @@ script()
>  {
>  	$dtrace $dt_flags -s /dev/stdin <<EOF
>  	syscall::execve:entry
> -	/copyinstr((uintptr_t)args[1][0]) == "sleep" && args[1][1] &&
> -	 copyinstr((uintptr_t)args[1][1]) == "10000"/
> +	/(this->myargs = (uintptr_t *)copyin((uintptr_t)args[1], 2 * sizeof(char *)))
> +	 && copyinstr(this->myargs[0]) == "sleep"
> +	 && this->myargs[1]
> +	 && copyinstr(this->myargs[1]) == "10000"/
>  	{
>  		kill_pid = pid;
>  	}
> diff --git a/test/unittest/proc/tst.signal.sh b/test/unittest/proc/tst.signal.sh
> index 3f885759..1db10042 100755
> --- a/test/unittest/proc/tst.signal.sh
> +++ b/test/unittest/proc/tst.signal.sh
> @@ -12,8 +12,10 @@ script()
>  {
>  	$dtrace $dt_flags -s /dev/stdin <<EOF
>  	syscall::execve:entry
> -	/copyinstr((uintptr_t)args[1][0]) == "sleep" && args[1][1] &&
> -	 copyinstr((uintptr_t)args[1][1]) == "10000"/
> +	/(this->myargs = (uintptr_t *)copyin((uintptr_t)args[1], 2 * sizeof(char *)))
> +	 && copyinstr(this->myargs[0]) == "sleep"
> +	 && this->myargs[1]
> +	 && copyinstr(this->myargs[1]) == "10000"/
>  	{
>  		sig_pid = pid;
>  	}
> @@ -23,12 +25,14 @@ script()
>  	 sig_pid == args[1]->pr_pid && args[2] != SIGUSR1/
>  	{
>  		/* Wrong signal being sent. */
> +		printf("wrong signal sent: %d vs %d\n", args[2], SIGUSR1);
>  		exit(1);
>  	}
>  
>  	proc:::signal-handle
>  	/sig_pid == pid/
>  	{
> +		printf("signal received %d\n", args[0]);
>  		exit(args[0] == SIGUSR1 ? 0 : 1);
>  	}
>  
> -- 
> 2.18.4
> 
>