On Wed, 15 Jul 2015, SF Markus Elfring wrote:
> Hello,
>
> I am looking for a specific programming mistake with the help
> of the semantic patch language once more.
>
>
> 1. A SmPL approach like the following seems to work to some degree.
>
> @find_unsafe@
> identifier receiver =~ "^(?x)
> (?:
> (?:alarm|parent|sig(?:chld|hup|term))_handler
> |
> handle_sigterm
> |
> (?:CancelJ|cancel_j)ob
> )$";
> @@
> void receiver(...)
> {
> ...
> (
> - exit(...);
> |
> - fprintf(...);
> )
> ...
> }
When you make a transformation, you get a forall semantics - every control
flow path in the function must respect your pattern. When you search for
something with * you get an exists semantics - there must exist a path
that has the patern you specify. If you don't like these defaults, you
can change them, by putting exists or forall in the initial @@, or by
putting when exists or when forall on the ...
Furthermore, ... matches the shortest path between two points. That is,
in your rule, you will only match the case where a control-flow patch
contains exactly one call to either exit or fprintf. If you want to allow
more occurrences, you can use <... ...> with searches for 0 or more or
something, or <+... ...+> which searches for one or more.
I believe the parallelism error has been fixed. I'm not sure if it was in
the release, though. If your semantic patch is called foo.cocci, check
that you don't have a file/directory called foo in the current directory.
julia
>
> elfring@Sonne:~/Projekte/CUPS> spatch.opt -sp-file async-unsafe1.cocci -dir
> lokal > async-unsafe1.diff && cat async-unsafe1.diff
> init_defs_builtins: /usr/local/lib/coccinelle/standard.h
> …
> Skipping:lokal/vcnet/regex/regerror.c
> diff -u -p a/backend/ipp.c b/backend/ipp.c
> --- a/backend/ipp.c
> +++ b/backend/ipp.c
> @@ -3271,8 +3271,6 @@ sigterm_handler(int sig) /* I - Signal
>
> if (tmpfilename[0])
> unlink(tmpfilename);
> -
> - exit(1);
>
>
>
> 2. I have tried another SmPL script variant out.
>
> @show_unsafe@
> identifier receiver =~ "^(?x)
> (?:
> (?:alarm|parent|sig(?:chld|hup|term))_handler
> |
> handle_sigterm
> |
> (?:CancelJ|cancel_j)ob
> )$";
> @@
> void receiver(...)
> {
> ...
> (
> * exit
> |f
> * fprintf
> )
> (...);
> ...
> }
>
> elfring@Sonne:~/Projekte/CUPS> spatch.opt -sp-file async-unsafe2.cocci -dir
> lokal > async-unsafe2.diff && cat async-unsafe2.diff
> init_defs_builtins: /usr/local/lib/coccinelle/standard.h
> …
> diff -u -p lokal/backend/dnssd.c /tmp/nothing/backend/dnssd.c
> --- lokal/backend/dnssd.c
> +++ /tmp/nothing/backend/dnssd.c
> @@ -1289,7 +1289,6 @@ sigterm_handler(int sig) /* I - Signal
> (void)sig;
>
> if (job_canceled)
> - exit(CUPS_BACKEND_OK);
> else
> job_canceled = 1;
> }
> diff -u -p lokal/backend/usb-darwin.c /tmp/nothing/backend/usb-darwin.c
> --- lokal/backend/usb-darwin.c
> +++ /tmp/nothing/backend/usb-darwin.c
> @@ -2262,9 +2262,7 @@ sigterm_handler(int sig) /* I - Signal
> while (waitpid(child_pid, &status, 0) < 0 && errno == EINTR);
>
> if (WIFEXITED(status))
> - exit(WEXITSTATUS(status));
> else if (status == SIGTERM || status == SIGKILL)
> - exit(0);
> else
> {
> fprintf(stderr, "DEBUG: Child crashed on signal %d\n", status);
> diff -u -p lokal/backend/ipp.c /tmp/nothing/backend/ipp.c
> --- lokal/backend/ipp.c
> +++ /tmp/nothing/backend/ipp.c
> @@ -3272,7 +3272,6 @@ sigterm_handler(int sig) /* I - Signal
> if (tmpfilename[0])
> unlink(tmpfilename);
>
> - exit(1);
> }
>
>
> Why did the first approach find less?
>
>
> Should the call of the function "fprintf" in the source file "usb-darwin.c"
> also be marked for further considerations here?
> Are there any more update candidates to consider?
>
>
>
> 3. If I add the parameter "-jobs 4" to the shown commands for a parallel
> source code analysis, I wonder about a message like the following.
>
> [Pid 5399]: Error creating async-unsafe2 : File exists; proceeding without
> stdout/stderr redirection
>
> Should it be avoided usually?
>
> Regards,
> Markus
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