On Thu, May 16, 2024 at 7:45 PM Jim Cromie <jim.cromie@gmail.com> wrote:
>
> Multi-query strings have long allowed:
Missing been ?
>
> modprobe drm dyndbg="class DRM_UT_CORE +p; class DRM_UT_KMS +p"
> modprobe drm dyndbg=<<EOX
> class DRM_UT_CORE +p
> class DRM_UT_KMS +p
> EOX
>
> More recently, the need for quoting was avoided by treating a comma
> like a space/token-terminator:
>
> modprobe drm dyndbg=class,DRM_UT_CORE,+p\;class,DRM_UT_KMS,+p
>
> That worked, but it left unfinished business; the semicolon in the
> example above is a shell special-char (one of the bash control
> operators), so it is brittle when passed in/down/around scripts. In
> particular, it fails when passed to vng (virtme-ng).
>
> So this patch adds '%' to the existing ';' and '\n' multi-cmd
> separators, which is more shell-friendly, and also avoids quoting and
> escaping hassles.
>
> NOTE: it does break format matching on '%' patterns:
>
> bash-5.2# ddcmd 'format "find-me: %foo" +p'
> [ 203.900581] dyndbg: read 26 bytes from userspace
> [ 203.900883] dyndbg: query 0: "format "find-me: " mod:*
> [ 203.901118] dyndbg: unclosed quote: find-me:
> [ 203.901355] dyndbg: tokenize failed
> [ 203.901529] dyndbg: query 1: "foo" +p" mod:*
> [ 203.901957] dyndbg: split into words: "foo"" "+p"
> [ 203.902243] dyndbg: op='+' flags=0x1 maskp=0xffffffff
> [ 203.902458] dyndbg: expecting pairs of match-spec <value>
> [ 203.902703] dyndbg: query parse failed
> [ 203.902871] dyndbg: processed 2 queries, with 0 matches, 2 errs
> bash: echo: write error: Invalid argument
>
> The '%' splits the input into 2 queries, and both fail. Given the
> limited utility of matching against the working parts of a format
> string "foo: %d bar %s", nothing is actually lost here.
>
> Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
> ---
> lib/dynamic_debug.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/lib/dynamic_debug.c b/lib/dynamic_debug.c
> index c1bc728cb050..625838bd74aa 100644
> --- a/lib/dynamic_debug.c
> +++ b/lib/dynamic_debug.c
> @@ -596,7 +596,7 @@ static int ddebug_exec_queries(char *query, const char *modname)
> int i, errs = 0, exitcode = 0, rc, nfound = 0;
>
> for (i = 0; query; query = split) {
> - split = strpbrk(query, ";\n");
> + split = strpbrk(query, "%;\n");
> if (split)
> *split++ = '\0';
>
> --
> 2.45.0
>