[PATCH v2]: perf record: enable arbitrary event names thru name= modifier

[Alexey Budankov]

Enable complex event names containing [.:=,] symbols to be encoded into Perf 
trace using name= modifier e.g. like this:

perf record -e cpu/name=\'OFFCORE_RESPONSE:request=DEMAND_RFO:response=L3_HIT.SNOOP_HITM\',\
		period=0x3567e0,event=0x3c,cmask=0x1/Duk ./futex

Below is how it looks like in the report output. Please note explicit escaped 
quoting at cmdline string in the header so that thestring can be directly reused
for another collection in shell:

perf report --header

# ========
...
# cmdline : /root/abudanko/kernel/tip/tools/perf/perf record -v -e cpu/name=\'OFFCORE_RESPONSE:request=DEMAND_RFO:response=L3_HIT.SNOOP_HITM\',period=0x3567e0,event=0x3c,cmask=0x1/Duk ./futex 
# event : name = OFFCORE_RESPONSE:request=DEMAND_RFO:response=L3_HIT.SNOOP_HITM, , type = 4, size = 112, config = 0x100003c, { sample_period, sample_freq } = 3500000, sample_type = IP|TID|TIME, disabled = 1, inh
...
# ========
#
#
# Total Lost Samples: 0
#
# Samples: 24K of event 'OFFCORE_RESPONSE:request=DEMAND_RFO:response=L3_HIT.SNOOP_HITM'
# Event count (approx.): 86492000000
#
# Overhead  Command  Shared Object     Symbol                                        
# ........  .......  ................  ..............................................
#
    14.75%  futex    [kernel.vmlinux]  [k] __entry_trampoline_start
...

Signed-off-by: Alexey Budankov <alexey.budankov@xxxxxxxxxxxxxxx>
---
Changes in v2:
- aligned break according to coding guidelines;
- put comment regarding expected quoting rules; 
---
 tools/perf/util/header.c       | 20 ++++++++++++++++++--
 tools/perf/util/parse-events.l | 18 +++++++++++++++++-
 2 files changed, 35 insertions(+), 3 deletions(-)

diff --git a/tools/perf/util/header.c b/tools/perf/util/header.c
index a8bff2178fbc..08176e8cb3b4 100644
--- a/tools/perf/util/header.c
+++ b/tools/perf/util/header.c
@@ -1459,8 +1459,24 @@ static void print_cmdline(struct feat_fd *ff, FILE *fp)
 
 	fprintf(fp, "# cmdline : ");
 
-	for (i = 0; i < nr; i++)
-		fprintf(fp, "%s ", ff->ph->env.cmdline_argv[i]);
+	for (i = 0; i < nr; i++) {
+		char *argv_i = strdup(ff->ph->env.cmdline_argv[i]);
+		if (!argv_i) {
+			fprintf(fp, "%s ", ff->ph->env.cmdline_argv[i]);
+		} else {
+			char *mem = argv_i;
+			do {
+				char *quote = strchr(argv_i, '\'');
+				if (!quote)
+					break;
+				*quote++ = '\0';
+				fprintf(fp, "%s\\\'", argv_i);
+				argv_i = quote;
+			} while (1);
+			fprintf(fp, "%s ", argv_i);
+			free(mem);
+		}
+	}
 	fputc('\n', fp);
 }
 
diff --git a/tools/perf/util/parse-events.l b/tools/perf/util/parse-events.l
index a1a01b1ac8b8..c6d2bce4c017 100644
--- a/tools/perf/util/parse-events.l
+++ b/tools/perf/util/parse-events.l
@@ -53,7 +53,21 @@ static int str(yyscan_t scanner, int token)
 	YYSTYPE *yylval = parse_events_get_lval(scanner);
 	char *text = parse_events_get_text(scanner);
 
-	yylval->str = strdup(text);
+	if (text[0] != '\'') {
+		yylval->str = strdup(text);
+	} else {
+		/*
+		 * If a text tag specified on the command line 
+		 * contains opening single quite ' then it is 
+		 * expected that the tag ends with single quote 
+		 * as well, like this:
+		 *     name=\'CPU_CLK_UNHALTED.THREAD:cmask=1\'
+		 * quotes need to be escaped to bypass shell 
+		 * processing.
+		 */
+		yylval->str = strndup(&text[1], strlen(text) - 2);
+	}
+
 	return token;
 }
 
@@ -176,6 +190,7 @@ num_dec		[0-9]+
 num_hex		0x[a-fA-F0-9]+
 num_raw_hex	[a-fA-F0-9]+
 name		[a-zA-Z_*?\[\]][a-zA-Z0-9_*?.\[\]]*
+name_tag	[\'][a-zA-Z_*?\[\]][a-zA-Z0-9_*?\-,\.\[\]:=]*[\']
 name_minus	[a-zA-Z_*?][a-zA-Z0-9\-_*?.:]*
 drv_cfg_term	[a-zA-Z0-9_\.]+(=[a-zA-Z0-9_*?\.:]+)?
 /* If you add a modifier you need to update check_modifier() */
@@ -344,6 +359,7 @@ r{num_raw_hex}		{ return raw(yyscanner); }
 {bpf_object}		{ if (!isbpf(yyscanner)) { USER_REJECT }; return str(yyscanner, PE_BPF_OBJECT); }
 {bpf_source}		{ if (!isbpf(yyscanner)) { USER_REJECT }; return str(yyscanner, PE_BPF_SOURCE); }
 {name}			{ return pmu_str_check(yyscanner); }
+{name_tag}		{ return str(yyscanner, PE_NAME); }
 "/"			{ BEGIN(config); return '/'; }
 -			{ return '-'; }
 ,			{ BEGIN(event); return ','; }