[PATCH v9 21/52] dyndbg: split multi-query strings with %

Jim Cromie
2024-07-02T21:58:41Z

Since commit
85f7f6c0edb8 ("dynamic_debug: process multiple debug-queries on a line")

Multi-query commands have been allowed:

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 works, but it needs the escaped semicolon, which 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-command
separators, which is more shell-friendly, so you can more fully avoid
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 235d85765b63..dcec7b3657bb 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';

--
2.45.2