linux-kernel - [PATCH v2 2/4] tracing: Update synth command errors

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Message-Id: <338e7cbe92e1d1c7db119ce240352010ac841535.1603484117.git.zanussi@kernel.org>
Date:   Fri, 23 Oct 2020 15:33:53 -0500
From:   Tom Zanussi <zanussi@...nel.org>
To:     rostedt@...dmis.org, axelrasmussen@...gle.com
Cc:     mhiramat@...nel.org, linux-kernel@...r.kernel.org
Subject: [PATCH v2 2/4] tracing: Update synth command errors

Since array types are handled differently, errors referencing them
also need to be handled differently.  Add and use a new
INVALID_ARRAY_SPEC error.  Also add INVALID_CMD and INVALID_DYN_CMD to
catch and display the correct form for badly-formed commands, which
can also be used in place of CMD_INCOMPLETE, which is removed, and
remove CMD_TOO_LONG, since it's no longer used.

Signed-off-by: Tom Zanussi <zanussi@...nel.org>
---
 kernel/trace/trace_events_synth.c | 66 +++++++++++++++++++++++++++----
 1 file changed, 58 insertions(+), 8 deletions(-)

diff --git a/kernel/trace/trace_events_synth.c b/kernel/trace/trace_events_synth.c
index 90c1790ed1d6..1aa808791f56 100644
--- a/kernel/trace/trace_events_synth.c
+++ b/kernel/trace/trace_events_synth.c
@@ -23,13 +23,14 @@
 #undef ERRORS
 #define ERRORS	\
 	C(BAD_NAME,		"Illegal name"),		\
-	C(CMD_INCOMPLETE,	"Incomplete command"),		\
+	C(INVALID_CMD,		"Command must be of the form: <name> field[;field] ..."),\
+	C(INVALID_DYN_CMD,	"Command must be of the form: s or -:[synthetic/]<name> field[;field] ..."),\
 	C(EVENT_EXISTS,		"Event already exists"),	\
 	C(TOO_MANY_FIELDS,	"Too many fields"),		\
 	C(INCOMPLETE_TYPE,	"Incomplete type"),		\
 	C(INVALID_TYPE,		"Invalid type"),		\
-	C(INVALID_FIELD,	"Invalid field"),		\
-	C(CMD_TOO_LONG,		"Command too long"),
+	C(INVALID_FIELD,        "Invalid field"),		\
+	C(INVALID_ARRAY_SPEC,	"Invalid array specification"),
 
 #undef C
 #define C(a, b)		SYNTH_ERR_##a
@@ -643,6 +644,10 @@ static struct synth_field *parse_synth_field(int argc, char **argv)
 
 	size = synth_field_size(field->type);
 	if (size < 0) {
+		if (array)
+			synth_err(SYNTH_ERR_INVALID_ARRAY_SPEC, errpos(field_name));
+		else
+			synth_err(SYNTH_ERR_INVALID_TYPE, errpos(field_type));
 		ret = -EINVAL;
 		goto free;
 	} else if (size == 0) {
@@ -1158,7 +1163,7 @@ static int __create_synth_event(const char *name, const char *raw_fields)
 	mutex_lock(&event_mutex);
 
 	if (name[0] == '\0') {
-		synth_err(SYNTH_ERR_CMD_INCOMPLETE, 0);
+		synth_err(SYNTH_ERR_INVALID_CMD, 0);
 		ret = -EINVAL;
 		goto out;
 	}
@@ -1212,7 +1217,7 @@ static int __create_synth_event(const char *name, const char *raw_fields)
 	}
 
 	if (n_fields == 0) {
-		synth_err(SYNTH_ERR_CMD_INCOMPLETE, 0);
+		synth_err(SYNTH_ERR_INVALID_CMD, 0);
 		ret = -EINVAL;
 		goto err;
 	}
@@ -1350,13 +1355,42 @@ int synth_event_delete(const char *event_name)
 }
 EXPORT_SYMBOL_GPL(synth_event_delete);
 
+static int check_command(const char *raw_command)
+{
+	char **argv = NULL, *cmd, *saved_cmd, *name_and_field;
+	int argc, ret = 0;
+
+	cmd = saved_cmd = kstrdup(raw_command, GFP_KERNEL);
+	if (!cmd)
+		return -ENOMEM;
+
+	name_and_field = strsep(&cmd, ";");
+	if (!name_and_field) {
+		ret = -EINVAL;
+		goto free;
+	}
+
+	argv = argv_split(GFP_KERNEL, name_and_field, &argc);
+	if (!argv) {
+		ret = -ENOMEM;
+		goto free;
+	}
+
+	if (argc < 3)
+		ret = -EINVAL;
+free:
+	kfree(saved_cmd);
+	if (argv)
+		argv_free(argv);
+
+	return ret;
+}
+
 static int create_or_delete_synth_event(const char *raw_command)
 {
 	char **argv, *name = NULL, *fields;
 	int argc = 0, ret = 0;
 
-	last_cmd_set(raw_command);
-
 	argv = argv_split(GFP_KERNEL, raw_command, &argc);
 	if (!argv)
 		return -ENOMEM;
@@ -1364,9 +1398,16 @@ static int create_or_delete_synth_event(const char *raw_command)
 	if (!argc)
 		goto free;
 
+	last_cmd_set(raw_command);
+
+	ret = check_command(raw_command);
+	if (ret) {
+		synth_err(SYNTH_ERR_INVALID_CMD, 0);
+		goto free;
+	}
+
 	name = argv[0];
 
-	/* trace_run_command() ensures argc != 0 */
 	if (name[0] == '!') {
 		ret = synth_event_delete(name + 1);
 		goto free;
@@ -1951,12 +1992,21 @@ static int create_synth_event(const char *raw_command)
 	if (strchr(name, '/')) {
 		len = str_has_prefix(name, SYNTH_SYSTEM "/");
 		if (len == 0) {
+			synth_err(SYNTH_ERR_INVALID_DYN_CMD, 0);
 			ret = -EINVAL;
 			goto free;
 		}
 		name += len;
 	}
 
+	len = name - argv[0];
+
+	ret = check_command(raw_command + len);
+	if (ret) {
+		synth_err(SYNTH_ERR_INVALID_CMD, 0);
+		goto free;
+	}
+
 	fields = strstr(raw_command, name);
 	fields += strlen(name);
 
-- 
2.17.1