[DTrace-devel] [PATCH] test: Update -xmodpath test

Tue Jan 30 16:27:28 UTC 2024

On Mon, Dec 18, 2023 at 04:43:38PM -0500, eugene.loh at oracle.com wrote:
> 
> We test -xmodpath by checking that pointing modpath to:
> - an empty directory produces "bad" results
> - an appropriate symlink reproduces good (default) results
> 
> With the addition of a BTF-to-CTF convertor, however, DTrace basically
> functions even in the absence of CTF info.
> 
> One signature of the convertor, though, is that rawtp-provider args[]
> type information will be (void*) regardless of what the actual type is.
> Use this signature to verify that -xmodpath is working.
> 
> One complication is that a trial-and-error method of getting rawtp args[]
> info is used if there is no HAVE_LIBCTF.  In this case, rawtp args[]
> types will be uint64_t, even when no -xmodpath is specified.  Skip the
> test in this case.
> 
> To review:
> 
> - If no HAVE_LIBCTF, rawtp args[] type will always be uint64_t.
>   Skip the test in this case.
> 
> - If HAVE_LIBCTF but -xmodpath points at an empty directory, many
>   DTrace features should still work, but rawtp args[] types will
>   all be (void*).  Check that -xmodpath=empty produces (void*).
> 
> - Under "normal" circumstances, many rawtp args[] types will be
>   neither uint64_t nor (void*).  Check such results in the default
>   case and when -xmodpath points at a valid CTF archive.
> 
> Signed-off-by: Eugene Loh <eugene.loh at oracle.com>

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

> ---
>  test/unittest/options/tst.modpath.r  | 18 ++-----
>  test/unittest/options/tst.modpath.sh | 74 ++++++++++++++++++++++------
>  test/unittest/options/tst.modpath.x  | 19 ++++++-
>  3 files changed, 80 insertions(+), 31 deletions(-)
>  mode change 120000 => 100755 test/unittest/options/tst.modpath.x
> 
> diff --git a/test/unittest/options/tst.modpath.r b/test/unittest/options/tst.modpath.r
> index 464a19be..0fc2bb61 100644
> --- a/test/unittest/options/tst.modpath.r
> +++ b/test/unittest/options/tst.modpath.r
> @@ -1,14 +1,4 @@
> -                   FUNCTION:NAME
> -                          :BEGIN 
> -
> -sanity check on DTrace passed
> -DTrace correctly fails when modpath is an empty directory
> -                   FUNCTION:NAME
> -                          :BEGIN 
> -
> -DTrace works with modpath and a linked CTF archive
> --- @@stderr --
> -dtrace: description 'BEGIN ' matched 1 probe
> -dtrace: description 'BEGIN ' matched 1 probe
> -dtrace: could not enable tracing: Module does not contain any CTF data
> -dtrace: description 'BEGIN ' matched 1 probe
> +basic check on DTrace passed
> +empty check on DTrace passed
> +final check on DTrace passed
> +all checks pass
> diff --git a/test/unittest/options/tst.modpath.sh b/test/unittest/options/tst.modpath.sh
> index cd26114f..0f269123 100755
> --- a/test/unittest/options/tst.modpath.sh
> +++ b/test/unittest/options/tst.modpath.sh
> @@ -12,36 +12,78 @@ DIRNAME="$tmpdir/modpath.$$.$RANDOM"
>  mkdir -p $DIRNAME
>  cd $DIRNAME
>  
> -# create the directory where the CTF archive will end up
> +# Create the directory where the CTF archive will end up.
>  mkdir -p mydirectory/kernel
>  
> -# sanity check that DTrace works
> -$dtrace $dt_flags -n 'BEGIN {exit(0)}'
> +# Basic check that DTrace works.
> +$dtrace $dt_flags                       -lvP rawtp > basic.out
>  if [ $? -ne 0 ]; then
> -	echo ERROR: sanity check on DTrace failed
> +	echo ERROR: basic check on DTrace failed
> +	cat basic.out
>  	exit 1
>  else
> -	echo sanity check on DTrace passed
> +	echo basic check on DTrace passed
>  fi
>  
> -# verify that modpath directs us to the (empty) directory
> -$dtrace $dt_flags -xmodpath=mydirectory -n 'BEGIN {exit(0)}'
> +# Verify that modpath directs us to the (empty) directory, with no CTF info.
> +$dtrace $dt_flags -xmodpath=mydirectory -lvP rawtp > empty.out
>  if [ $? -ne 0 ]; then
> -	echo DTrace correctly fails when modpath is an empty directory
> -else
> -	echo ERROR: DTrace unexpectedly passes with modpath set to empty directory
> +	echo ERROR: empty check on DTrace failed
> +	cat empty.out
>  	exit 1
> +else
> +	echo empty check on DTrace passed
>  fi
>  
> -# link a CTF archive to our directory
> +# Link a CTF archive to our directory.
>  ln -s /lib/modules/$(uname -r)/kernel/vmlinux.ctfa mydirectory/kernel/vmlinux.ctfa
>  
> -# verify that modpath now works
> -$dtrace $dt_flags -xmodpath=mydirectory -n 'BEGIN {exit(0)}'
> +# Verify that modpath now works.
> +$dtrace $dt_flags -xmodpath=mydirectory -lvP rawtp > final.out
>  if [ $? -ne 0 ]; then
> -	echo ERROR: DTrace somehow fails
> +	echo ERROR: final check on DTrace failed
> +	cat final.out
>  	exit 1
>  else
> -	echo DTrace works with modpath and a linked CTF archive
> -	exit 0
> +	echo final check on DTrace passed
> +fi
> +
> +# Check the amount of CTF info we got from each run by seeing how many
> +# rawtp args have non-trivial type info.  While nempty should be 0,
> +# nbasic and nfinal should be substantial and likely identical (but
> +# we allow a generous tolerance).
> +
> +nbasic=`awk '/^[	 ]*args\[/ && !/uint64_t/ && !/void \*/' basic.out | wc -l`
> +nempty=`awk '/^[	 ]*args\[/ && !/uint64_t/ && !/void \*/' empty.out | wc -l`
> +nfinal=`awk '/^[	 ]*args\[/ && !/uint64_t/ && !/void \*/' final.out | wc -l`
> +
> +if [ $nempty -ne 0 ]; then
> +	echo ERROR: empty check turned up some CTF info
> +	cat empty.out
> +	echo got nbasic $nbasic nempty $nempty nfinal $nfinal
> +	exit 1
>  fi
> +if [ $nbasic -lt 1000 ]; then
> +	echo ERROR: basic check turned up little CTF info
> +	cat basic.out
> +	echo got nbasic $nbasic nempty $nempty nfinal $nfinal
> +	exit 1
> +fi
> +if [ $nfinal -lt 1000 ]; then
> +	echo ERROR: final check turned up little CTF info
> +	cat final.out
> +	echo got nbasic $nbasic nempty $nempty nfinal $nfinal
> +	exit 1
> +fi
> +if [ $nbasic -gt $(($nfinal + 200)) -o $nfinal -gt $((nbasic + 200)) ]; then
> +	echo $nbasic $nfinal out of range
> +	echo ==== basic.out:
> +	cat basic.out
> +	echo ==== final.out:
> +	cat final.out
> +	echo got nbasic $nbasic nempty $nempty nfinal $nfinal
> +	exit 1
> +fi
> +
> +echo all checks pass
> +exit 0
> diff --git a/test/unittest/options/tst.modpath.x b/test/unittest/options/tst.modpath.x
> deleted file mode 120000
> index df5695cd..00000000
> --- a/test/unittest/options/tst.modpath.x
> +++ /dev/null
> @@ -1 +0,0 @@
> -tst.ctfpath.x
> \ No newline at end of file
> diff --git a/test/unittest/options/tst.modpath.x b/test/unittest/options/tst.modpath.x
> new file mode 100755
> index 00000000..6d483535
> --- /dev/null
> +++ b/test/unittest/options/tst.modpath.x
> @@ -0,0 +1,18 @@
> +#!/bin/bash
> +
> +# Skip test if there is no CTF archive.
> +if [ ! -r /lib/modules/$(uname -r)/kernel/vmlinux.ctfa ]; then
> +	echo "No CTF archive found for the kernel."
> +	exit 2
> +fi
> +
> +# Skip test if CTF info is not used for rawtp args[] types.  (If all rawtp
> +# args[] types are "uint64_t", this is a symptom of our using the back-up
> +# trial-and-error method.)
> +types=`$dtrace -lvP rawtp | awk '/^[ 	]*args/ { $1 = ""; print }' | sort -u`
> +if [ "$types" == " uint64_t" ]; then
> +	echo "not using CTF for rawtp args types"
> +	exit 2
> +fi
> +
> +exit 0
> -- 
> 2.18.4
> 
>