linux-kernel - [PATCH v2 11/16] perf parse-events: Improve error message for bad numbers

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Message-Id: <20240416061533.921723-12-irogers@google.com>
Date: Mon, 15 Apr 2024 23:15:27 -0700
From: Ian Rogers <irogers@...gle.com>
To: Peter Zijlstra <peterz@...radead.org>, Ingo Molnar <mingo@...hat.com>, 
	Arnaldo Carvalho de Melo <acme@...nel.org>, Namhyung Kim <namhyung@...nel.org>, 
	Mark Rutland <mark.rutland@....com>, 
	Alexander Shishkin <alexander.shishkin@...ux.intel.com>, Jiri Olsa <jolsa@...nel.org>, 
	Ian Rogers <irogers@...gle.com>, Adrian Hunter <adrian.hunter@...el.com>, 
	Kan Liang <kan.liang@...ux.intel.com>, James Clark <james.clark@....com>, 
	linux-perf-users@...r.kernel.org, linux-kernel@...r.kernel.org, 
	bpf@...r.kernel.org, Atish Patra <atishp@...osinc.com>, linux-riscv@...ts.infradead.org, 
	Beeman Strong <beeman@...osinc.com>
Subject: [PATCH v2 11/16] perf parse-events: Improve error message for bad numbers

Use the error handler from the parse_state to give a more informative
error message.

Before:
```
$ perf stat -e 'cycles/period=99999999999999999999/' true
event syntax error: 'cycles/period=99999999999999999999/'
                                  \___ parser error
Run 'perf list' for a list of valid events

 Usage: perf stat [<options>] [<command>]

    -e, --event <event>   event selector. use 'perf list' to list available events
```

After:
```
$ perf stat -e 'cycles/period=99999999999999999999/' true
event syntax error: 'cycles/period=99999999999999999999/'
                                  \___ parser error

event syntax error: '..les/period=99999999999999999999/'
                                  \___ Bad base 10 number "99999999999999999999"
Run 'perf list' for a list of valid events

 Usage: perf stat [<options>] [<command>]

    -e, --event <event>   event selector. use 'perf list' to list available events
```

Signed-off-by: Ian Rogers <irogers@...gle.com>
---
 tools/perf/util/parse-events.l | 40 ++++++++++++++++++++--------------
 1 file changed, 24 insertions(+), 16 deletions(-)

diff --git a/tools/perf/util/parse-events.l b/tools/perf/util/parse-events.l
index 6fe37003ab7b..0cd68c9f0d4f 100644
--- a/tools/perf/util/parse-events.l
+++ b/tools/perf/util/parse-events.l
@@ -18,26 +18,34 @@
 
 char *parse_events_get_text(yyscan_t yyscanner);
 YYSTYPE *parse_events_get_lval(yyscan_t yyscanner);
+int parse_events_get_column(yyscan_t yyscanner);
+int parse_events_get_leng(yyscan_t yyscanner);
 
-static int __value(YYSTYPE *yylval, char *str, int base, int token)
+static int get_column(yyscan_t scanner)
 {
-	u64 num;
-
-	errno = 0;
-	num = strtoull(str, NULL, base);
-	if (errno)
-		return PE_ERROR;
-
-	yylval->num = num;
-	return token;
+	return parse_events_get_column(scanner) - parse_events_get_leng(scanner);
 }
 
-static int value(yyscan_t scanner, int base)
+static int value(struct parse_events_state *parse_state, yyscan_t scanner, int base)
 {
 	YYSTYPE *yylval = parse_events_get_lval(scanner);
 	char *text = parse_events_get_text(scanner);
+	u64 num;
 
-	return __value(yylval, text, base, PE_VALUE);
+	errno = 0;
+	num = strtoull(text, NULL, base);
+	if (errno) {
+		struct parse_events_error *error = parse_state->error;
+		char *help = NULL;
+
+		if (asprintf(&help, "Bad base %d number \"%s\"", base, text) > 0)
+			parse_events_error__handle(error, get_column(scanner), help , NULL);
+
+		return PE_ERROR;
+	}
+
+	yylval->num = num;
+	return PE_VALUE;
 }
 
 static int str(yyscan_t scanner, int token)
@@ -283,8 +291,8 @@ r0x{num_raw_hex}	{ return str(yyscanner, PE_RAW); }
 	 */
 "/"/{digit}		{ return PE_BP_SLASH; }
 "/"/{non_digit}		{ BEGIN(config); return '/'; }
-{num_dec}		{ return value(yyscanner, 10); }
-{num_hex}		{ return value(yyscanner, 16); }
+{num_dec}		{ return value(_parse_state, yyscanner, 10); }
+{num_hex}		{ return value(_parse_state, yyscanner, 16); }
 	/*
 	 * We need to separate 'mem:' scanner part, in order to get specific
 	 * modifier bits parsed out. Otherwise we would need to handle PE_NAME
@@ -330,8 +338,8 @@ cgroup-switches					{ return sym(yyscanner, PERF_COUNT_SW_CGROUP_SWITCHES); }
 {lc_type}-{lc_op_result}-{lc_op_result}	{ return str(yyscanner, PE_LEGACY_CACHE); }
 mem:			{ BEGIN(mem); return PE_PREFIX_MEM; }
 r{num_raw_hex}		{ return str(yyscanner, PE_RAW); }
-{num_dec}		{ return value(yyscanner, 10); }
-{num_hex}		{ return value(yyscanner, 16); }
+{num_dec}		{ return value(_parse_state, yyscanner, 10); }
+{num_hex}		{ return value(_parse_state, yyscanner, 16); }
 
 {modifier_event}	{ return str(yyscanner, PE_MODIFIER_EVENT); }
 {name}			{ return str(yyscanner, PE_NAME); }
-- 
2.44.0.683.g7961c838ac-goog