linux-kernel - [PATCH v4 20/39] dyndbg: treat comma as a token separator

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Message-ID: <20240210235009.2405808-21-ukaszb@chromium.org>
Date: Sun, 11 Feb 2024 00:49:50 +0100
From: Łukasz Bartosik <ukaszb@...omium.org>
To: Jason Baron <jbaron@...mai.com>,
	Jim Cromie <jim.cromie@...il.com>,
	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	Andrew Morton <akpm@...ux-foundation.org>,
	Kees Cook <keescook@...omium.org>,
	Douglas Anderson <dianders@...omium.org>
Cc: Guenter Roeck <groeck@...gle.com>,
	Yaniv Tzoreff <yanivt@...gle.com>,
	Benson Leung <bleung@...gle.com>,
	Steven Rostedt <rostedt@...dmis.org>,
	Vincent Whitchurch <vincent.whitchurch@...s.com>,
	Pekka Paalanen <ppaalanen@...il.com>,
	Sean Paul <seanpaul@...omium.org>,
	Daniel Vetter <daniel@...ll.ch>,
	Simon Ser <contact@...rsion.fr>,
	John Ogness <john.ogness@...utronix.de>,
	Petr Mladek <pmladek@...e.com>,
	Sergey Senozhatsky <sergey.senozhatsky@...il.com>,
	linux-kernel@...r.kernel.org,
	upstream@...ihalf.com
Subject: [PATCH v4 20/39] dyndbg: treat comma as a token separator

From: Jim Cromie <jim.cromie@...il.com>

Treat comma as a token terminator, just like a space.  This allows a
user to avoid quoting hassles when spaces are otherwise needed:

 :#> modprobe drm dyndbg=class,DRM_UT_CORE,+p\;class,DRM_UT_KMS,+p

or as a boot arg:

 drm.dyndbg=class,DRM_UT_CORE,+p  # todo: support multi-query here

Given the myriad ways a boot-line can be assembled and then passed
in/down/around shell based tools, if the >control parser treats commas
like spacees, this would allow side-stepping all sorts of quoting
hassles thru those layers.

This change apart from existing query format:

 modprobe test_dynamic_debug dyndbg="class D2_CORE +p"

introduces new format:

 modprobe test_dynamic_debug dyndbg=class,D2_CORE,+p

Signed-off-by: Jim Cromie <jim.cromie@...il.com>
Co-developed-by: Łukasz Bartosik <ukaszb@...omium.org>
Signed-off-by: Łukasz Bartosik <ukaszb@...omium.org>
---
 lib/dynamic_debug.c | 20 ++++++++++++++++----
 1 file changed, 16 insertions(+), 4 deletions(-)

diff --git a/lib/dynamic_debug.c b/lib/dynamic_debug.c
index 20bfb6de2404..78b06a617918 100644
--- a/lib/dynamic_debug.c
+++ b/lib/dynamic_debug.c
@@ -650,6 +650,14 @@ static int ddebug_change(const struct ddebug_query *query,
 	return nfound;
 }
 
+static char *skip_spaces_and_comma(const char *str)
+{
+	str = skip_spaces(str);
+	if (*str == ',')
+		str = skip_spaces(++str);
+	return (char *)str;
+}
+
 /*
  * Split the buffer `buf' into space-separated words.
  * Handles simple " and ' quoting, i.e. without nested,
@@ -663,12 +671,16 @@ static int ddebug_tokenize(char *buf, char *words[], int maxwords)
 	while (*buf) {
 		char *end;
 
-		/* Skip leading whitespace */
-		buf = skip_spaces(buf);
+		/* Skip leading whitespace and comma */
+		buf = skip_spaces_and_comma(buf);
 		if (!*buf)
 			break;	/* oh, it was trailing whitespace */
 		if (*buf == '#')
 			break;	/* token starts comment, skip rest of line */
+		if (*buf == ',') {
+			buf++;
+			continue;
+		}
 
 		/* find `end' of word, whitespace separated or quoted */
 		if (*buf == '"' || *buf == '\'') {
@@ -680,7 +692,7 @@ static int ddebug_tokenize(char *buf, char *words[], int maxwords)
 				return -EINVAL;	/* unclosed quote */
 			}
 		} else {
-			for (end = buf; *end && !isspace(*end); end++)
+			for (end = buf; *end && !isspace(*end) && *end != ','; end++)
 				;
 			if (end == buf) {
 				pr_err("parse err after word:%d=%s\n", nwords,
@@ -993,7 +1005,7 @@ static int ddebug_exec_queries(char *query, const char *modname)
 		if (split)
 			*split++ = '\0';
 
-		query = skip_spaces(query);
+		query = skip_spaces_and_comma(query);
 		if (!query || !*query || *query == '#')
 			continue;
 
-- 
2.43.0.687.g38aa6559b0-goog