2023-04-04 13:37:57

by Ian Rogers

[permalink] [raw]
Subject: [PATCH v2] perf pmu: Make parser reentrant

By default bison uses global state for compatibility with yacc. Make
the parser reentrant so that it may be used in asynchronous and
multithreaded situations.

Signed-off-by: Ian Rogers <[email protected]>
---
tools/perf/util/pmu.c | 24 ++++++++++++++++++------
tools/perf/util/pmu.h | 2 +-
tools/perf/util/pmu.l | 17 ++++++++++++-----
tools/perf/util/pmu.y | 5 ++++-
4 files changed, 35 insertions(+), 13 deletions(-)

diff --git a/tools/perf/util/pmu.c b/tools/perf/util/pmu.c
index 78a407b42ad1..f603cdabf797 100644
--- a/tools/perf/util/pmu.c
+++ b/tools/perf/util/pmu.c
@@ -24,6 +24,8 @@
#include "evsel.h"
#include "pmu.h"
#include "pmus.h"
+#include "pmu-bison.h"
+#include "pmu-flex.h"
#include "parse-events.h"
#include "print-events.h"
#include "header.h"
@@ -57,9 +59,6 @@ struct perf_pmu_format {
struct list_head list;
};

-int perf_pmu_parse(struct list_head *list, char *name);
-extern FILE *perf_pmu_in;
-
static bool hybrid_scanned;

static struct perf_pmu *perf_pmu__find2(int dirfd, const char *name);
@@ -81,6 +80,8 @@ int perf_pmu__format_parse(int dirfd, struct list_head *head)
while (!ret && (evt_ent = readdir(format_dir))) {
char *name = evt_ent->d_name;
int fd;
+ void *scanner;
+ FILE *file;

if (!strcmp(name, ".") || !strcmp(name, ".."))
continue;
@@ -91,9 +92,20 @@ int perf_pmu__format_parse(int dirfd, struct list_head *head)
if (fd < 0)
break;

- perf_pmu_in = fdopen(fd, "r");
- ret = perf_pmu_parse(head, name);
- fclose(perf_pmu_in);
+ file = fdopen(fd, "r");
+ if (!file)
+ break;
+
+ ret = perf_pmu_lex_init(&scanner);
+ if (ret) {
+ fclose(file);
+ break;
+ }
+
+ perf_pmu_set_in(file, scanner);
+ ret = perf_pmu_parse(head, name, scanner);
+ perf_pmu_lex_destroy(scanner);
+ fclose(file);
}

closedir(format_dir);
diff --git a/tools/perf/util/pmu.h b/tools/perf/util/pmu.h
index 32c3a75bca0e..d53618c65c92 100644
--- a/tools/perf/util/pmu.h
+++ b/tools/perf/util/pmu.h
@@ -206,7 +206,7 @@ int perf_pmu__check_alias(struct perf_pmu *pmu, struct list_head *head_terms,
struct perf_pmu_info *info);
struct list_head *perf_pmu__alias(struct perf_pmu *pmu,
struct list_head *head_terms);
-void perf_pmu_error(struct list_head *list, char *name, char const *msg);
+void perf_pmu_error(struct list_head *list, char *name, void *scanner, char const *msg);

int perf_pmu__new_format(struct list_head *list, char *name,
int config, unsigned long *bits);
diff --git a/tools/perf/util/pmu.l b/tools/perf/util/pmu.l
index 58b4926cfaca..67b247be693b 100644
--- a/tools/perf/util/pmu.l
+++ b/tools/perf/util/pmu.l
@@ -1,4 +1,6 @@
%option prefix="perf_pmu_"
+%option reentrant
+%option bison-bridge

%{
#include <stdlib.h>
@@ -6,16 +8,21 @@
#include "pmu.h"
#include "pmu-bison.h"

-static int value(int base)
+char *perf_pmu_get_text(yyscan_t yyscanner);
+YYSTYPE *perf_pmu_get_lval(yyscan_t yyscanner);
+
+static int value(yyscan_t scanner, int base)
{
+ YYSTYPE *yylval = perf_pmu_get_lval(scanner);
+ char *text = perf_pmu_get_text(scanner);
long num;

errno = 0;
- num = strtoul(perf_pmu_text, NULL, base);
+ num = strtoul(text, NULL, base);
if (errno)
return PP_ERROR;

- perf_pmu_lval.num = num;
+ yylval->num = num;
return PP_VALUE;
}

@@ -25,7 +32,7 @@ num_dec [0-9]+

%%

-{num_dec} { return value(10); }
+{num_dec} { return value(yyscanner, 10); }
config { return PP_CONFIG; }
- { return '-'; }
: { return ':'; }
@@ -35,7 +42,7 @@ config { return PP_CONFIG; }

%%

-int perf_pmu_wrap(void)
+int perf_pmu_wrap(void *scanner __maybe_unused)
{
return 1;
}
diff --git a/tools/perf/util/pmu.y b/tools/perf/util/pmu.y
index e675d79a0274..dff4e892ac4d 100644
--- a/tools/perf/util/pmu.y
+++ b/tools/perf/util/pmu.y
@@ -1,6 +1,8 @@
-
+%define api.pure full
%parse-param {struct list_head *format}
%parse-param {char *name}
+%parse-param {void *scanner}
+%lex-param {void* scanner}

%{

@@ -78,6 +80,7 @@ PP_VALUE

void perf_pmu_error(struct list_head *list __maybe_unused,
char *name __maybe_unused,
+ void *scanner __maybe_unused,
char const *msg __maybe_unused)
{
}
--
2.40.0.348.gf938b09366-goog


2023-04-05 07:30:38

by Jiri Olsa

[permalink] [raw]
Subject: Re: [PATCH v2] perf pmu: Make parser reentrant

On Tue, Apr 04, 2023 at 06:36:30AM -0700, Ian Rogers wrote:
> By default bison uses global state for compatibility with yacc. Make
> the parser reentrant so that it may be used in asynchronous and
> multithreaded situations.
>
> Signed-off-by: Ian Rogers <[email protected]>

hum I can't apply this version on Arnaldo's perf/core:

patching file tools/perf/util/pmu.c
Hunk #2 succeeded at 59 with fuzz 1.
Hunk #3 FAILED at 80.
Hunk #4 FAILED at 90.
2 out of 4 hunks FAILED -- saving rejects to file tools/perf/util/pmu.c.rej
patching file tools/perf/util/pmu.h
patching file tools/perf/util/pmu.l
patching file tools/perf/util/pmu.y

jirka


> ---
> tools/perf/util/pmu.c | 24 ++++++++++++++++++------
> tools/perf/util/pmu.h | 2 +-
> tools/perf/util/pmu.l | 17 ++++++++++++-----
> tools/perf/util/pmu.y | 5 ++++-
> 4 files changed, 35 insertions(+), 13 deletions(-)
>
> diff --git a/tools/perf/util/pmu.c b/tools/perf/util/pmu.c
> index 78a407b42ad1..f603cdabf797 100644
> --- a/tools/perf/util/pmu.c
> +++ b/tools/perf/util/pmu.c
> @@ -24,6 +24,8 @@
> #include "evsel.h"
> #include "pmu.h"
> #include "pmus.h"
> +#include "pmu-bison.h"
> +#include "pmu-flex.h"
> #include "parse-events.h"
> #include "print-events.h"
> #include "header.h"
> @@ -57,9 +59,6 @@ struct perf_pmu_format {
> struct list_head list;
> };
>
> -int perf_pmu_parse(struct list_head *list, char *name);
> -extern FILE *perf_pmu_in;
> -
> static bool hybrid_scanned;
>
> static struct perf_pmu *perf_pmu__find2(int dirfd, const char *name);
> @@ -81,6 +80,8 @@ int perf_pmu__format_parse(int dirfd, struct list_head *head)
> while (!ret && (evt_ent = readdir(format_dir))) {
> char *name = evt_ent->d_name;
> int fd;
> + void *scanner;
> + FILE *file;
>
> if (!strcmp(name, ".") || !strcmp(name, ".."))
> continue;
> @@ -91,9 +92,20 @@ int perf_pmu__format_parse(int dirfd, struct list_head *head)
> if (fd < 0)
> break;
>
> - perf_pmu_in = fdopen(fd, "r");
> - ret = perf_pmu_parse(head, name);
> - fclose(perf_pmu_in);
> + file = fdopen(fd, "r");
> + if (!file)
> + break;
> +
> + ret = perf_pmu_lex_init(&scanner);
> + if (ret) {
> + fclose(file);
> + break;
> + }
> +
> + perf_pmu_set_in(file, scanner);
> + ret = perf_pmu_parse(head, name, scanner);
> + perf_pmu_lex_destroy(scanner);
> + fclose(file);
> }
>
> closedir(format_dir);
> diff --git a/tools/perf/util/pmu.h b/tools/perf/util/pmu.h
> index 32c3a75bca0e..d53618c65c92 100644
> --- a/tools/perf/util/pmu.h
> +++ b/tools/perf/util/pmu.h
> @@ -206,7 +206,7 @@ int perf_pmu__check_alias(struct perf_pmu *pmu, struct list_head *head_terms,
> struct perf_pmu_info *info);
> struct list_head *perf_pmu__alias(struct perf_pmu *pmu,
> struct list_head *head_terms);
> -void perf_pmu_error(struct list_head *list, char *name, char const *msg);
> +void perf_pmu_error(struct list_head *list, char *name, void *scanner, char const *msg);
>
> int perf_pmu__new_format(struct list_head *list, char *name,
> int config, unsigned long *bits);
> diff --git a/tools/perf/util/pmu.l b/tools/perf/util/pmu.l
> index 58b4926cfaca..67b247be693b 100644
> --- a/tools/perf/util/pmu.l
> +++ b/tools/perf/util/pmu.l
> @@ -1,4 +1,6 @@
> %option prefix="perf_pmu_"
> +%option reentrant
> +%option bison-bridge
>
> %{
> #include <stdlib.h>
> @@ -6,16 +8,21 @@
> #include "pmu.h"
> #include "pmu-bison.h"
>
> -static int value(int base)
> +char *perf_pmu_get_text(yyscan_t yyscanner);
> +YYSTYPE *perf_pmu_get_lval(yyscan_t yyscanner);
> +
> +static int value(yyscan_t scanner, int base)
> {
> + YYSTYPE *yylval = perf_pmu_get_lval(scanner);
> + char *text = perf_pmu_get_text(scanner);
> long num;
>
> errno = 0;
> - num = strtoul(perf_pmu_text, NULL, base);
> + num = strtoul(text, NULL, base);
> if (errno)
> return PP_ERROR;
>
> - perf_pmu_lval.num = num;
> + yylval->num = num;
> return PP_VALUE;
> }
>
> @@ -25,7 +32,7 @@ num_dec [0-9]+
>
> %%
>
> -{num_dec} { return value(10); }
> +{num_dec} { return value(yyscanner, 10); }
> config { return PP_CONFIG; }
> - { return '-'; }
> : { return ':'; }
> @@ -35,7 +42,7 @@ config { return PP_CONFIG; }
>
> %%
>
> -int perf_pmu_wrap(void)
> +int perf_pmu_wrap(void *scanner __maybe_unused)
> {
> return 1;
> }
> diff --git a/tools/perf/util/pmu.y b/tools/perf/util/pmu.y
> index e675d79a0274..dff4e892ac4d 100644
> --- a/tools/perf/util/pmu.y
> +++ b/tools/perf/util/pmu.y
> @@ -1,6 +1,8 @@
> -
> +%define api.pure full
> %parse-param {struct list_head *format}
> %parse-param {char *name}
> +%parse-param {void *scanner}
> +%lex-param {void* scanner}
>
> %{
>
> @@ -78,6 +80,7 @@ PP_VALUE
>
> void perf_pmu_error(struct list_head *list __maybe_unused,
> char *name __maybe_unused,
> + void *scanner __maybe_unused,
> char const *msg __maybe_unused)
> {
> }
> --
> 2.40.0.348.gf938b09366-goog
>

2023-04-05 09:44:02

by Arnaldo Carvalho de Melo

[permalink] [raw]
Subject: Re: [PATCH v2] perf pmu: Make parser reentrant



On April 5, 2023 4:25:18 AM GMT-03:00, Jiri Olsa <[email protected]> wrote:
>On Tue, Apr 04, 2023 at 06:36:30AM -0700, Ian Rogers wrote:
>> By default bison uses global state for compatibility with yacc. Make
>> the parser reentrant so that it may be used in asynchronous and
>> multithreaded situations.
>>
>> Signed-off-by: Ian Rogers <[email protected]>
>
>hum I can't apply this version on Arnaldo's perf/core:

Try on tmp.perf-tools-next

>
>patching file tools/perf/util/pmu.c
>Hunk #2 succeeded at 59 with fuzz 1.
>Hunk #3 FAILED at 80.
>Hunk #4 FAILED at 90.
>2 out of 4 hunks FAILED -- saving rejects to file tools/perf/util/pmu.c.rej
>patching file tools/perf/util/pmu.h
>patching file tools/perf/util/pmu.l
>patching file tools/perf/util/pmu.y
>
>jirka
>
>
>> ---
>> tools/perf/util/pmu.c | 24 ++++++++++++++++++------
>> tools/perf/util/pmu.h | 2 +-
>> tools/perf/util/pmu.l | 17 ++++++++++++-----
>> tools/perf/util/pmu.y | 5 ++++-
>> 4 files changed, 35 insertions(+), 13 deletions(-)
>>
>> diff --git a/tools/perf/util/pmu.c b/tools/perf/util/pmu.c
>> index 78a407b42ad1..f603cdabf797 100644
>> --- a/tools/perf/util/pmu.c
>> +++ b/tools/perf/util/pmu.c
>> @@ -24,6 +24,8 @@
>> #include "evsel.h"
>> #include "pmu.h"
>> #include "pmus.h"
>> +#include "pmu-bison.h"
>> +#include "pmu-flex.h"
>> #include "parse-events.h"
>> #include "print-events.h"
>> #include "header.h"
>> @@ -57,9 +59,6 @@ struct perf_pmu_format {
>> struct list_head list;
>> };
>>
>> -int perf_pmu_parse(struct list_head *list, char *name);
>> -extern FILE *perf_pmu_in;
>> -
>> static bool hybrid_scanned;
>>
>> static struct perf_pmu *perf_pmu__find2(int dirfd, const char *name);
>> @@ -81,6 +80,8 @@ int perf_pmu__format_parse(int dirfd, struct list_head *head)
>> while (!ret && (evt_ent = readdir(format_dir))) {
>> char *name = evt_ent->d_name;
>> int fd;
>> + void *scanner;
>> + FILE *file;
>>
>> if (!strcmp(name, ".") || !strcmp(name, ".."))
>> continue;
>> @@ -91,9 +92,20 @@ int perf_pmu__format_parse(int dirfd, struct list_head *head)
>> if (fd < 0)
>> break;
>>
>> - perf_pmu_in = fdopen(fd, "r");
>> - ret = perf_pmu_parse(head, name);
>> - fclose(perf_pmu_in);
>> + file = fdopen(fd, "r");
>> + if (!file)
>> + break;
>> +
>> + ret = perf_pmu_lex_init(&scanner);
>> + if (ret) {
>> + fclose(file);
>> + break;
>> + }
>> +
>> + perf_pmu_set_in(file, scanner);
>> + ret = perf_pmu_parse(head, name, scanner);
>> + perf_pmu_lex_destroy(scanner);
>> + fclose(file);
>> }
>>
>> closedir(format_dir);
>> diff --git a/tools/perf/util/pmu.h b/tools/perf/util/pmu.h
>> index 32c3a75bca0e..d53618c65c92 100644
>> --- a/tools/perf/util/pmu.h
>> +++ b/tools/perf/util/pmu.h
>> @@ -206,7 +206,7 @@ int perf_pmu__check_alias(struct perf_pmu *pmu, struct list_head *head_terms,
>> struct perf_pmu_info *info);
>> struct list_head *perf_pmu__alias(struct perf_pmu *pmu,
>> struct list_head *head_terms);
>> -void perf_pmu_error(struct list_head *list, char *name, char const *msg);
>> +void perf_pmu_error(struct list_head *list, char *name, void *scanner, char const *msg);
>>
>> int perf_pmu__new_format(struct list_head *list, char *name,
>> int config, unsigned long *bits);
>> diff --git a/tools/perf/util/pmu.l b/tools/perf/util/pmu.l
>> index 58b4926cfaca..67b247be693b 100644
>> --- a/tools/perf/util/pmu.l
>> +++ b/tools/perf/util/pmu.l
>> @@ -1,4 +1,6 @@
>> %option prefix="perf_pmu_"
>> +%option reentrant
>> +%option bison-bridge
>>
>> %{
>> #include <stdlib.h>
>> @@ -6,16 +8,21 @@
>> #include "pmu.h"
>> #include "pmu-bison.h"
>>
>> -static int value(int base)
>> +char *perf_pmu_get_text(yyscan_t yyscanner);
>> +YYSTYPE *perf_pmu_get_lval(yyscan_t yyscanner);
>> +
>> +static int value(yyscan_t scanner, int base)
>> {
>> + YYSTYPE *yylval = perf_pmu_get_lval(scanner);
>> + char *text = perf_pmu_get_text(scanner);
>> long num;
>>
>> errno = 0;
>> - num = strtoul(perf_pmu_text, NULL, base);
>> + num = strtoul(text, NULL, base);
>> if (errno)
>> return PP_ERROR;
>>
>> - perf_pmu_lval.num = num;
>> + yylval->num = num;
>> return PP_VALUE;
>> }
>>
>> @@ -25,7 +32,7 @@ num_dec [0-9]+
>>
>> %%
>>
>> -{num_dec} { return value(10); }
>> +{num_dec} { return value(yyscanner, 10); }
>> config { return PP_CONFIG; }
>> - { return '-'; }
>> : { return ':'; }
>> @@ -35,7 +42,7 @@ config { return PP_CONFIG; }
>>
>> %%
>>
>> -int perf_pmu_wrap(void)
>> +int perf_pmu_wrap(void *scanner __maybe_unused)
>> {
>> return 1;
>> }
>> diff --git a/tools/perf/util/pmu.y b/tools/perf/util/pmu.y
>> index e675d79a0274..dff4e892ac4d 100644
>> --- a/tools/perf/util/pmu.y
>> +++ b/tools/perf/util/pmu.y
>> @@ -1,6 +1,8 @@
>> -
>> +%define api.pure full
>> %parse-param {struct list_head *format}
>> %parse-param {char *name}
>> +%parse-param {void *scanner}
>> +%lex-param {void* scanner}
>>
>> %{
>>
>> @@ -78,6 +80,7 @@ PP_VALUE
>>
>> void perf_pmu_error(struct list_head *list __maybe_unused,
>> char *name __maybe_unused,
>> + void *scanner __maybe_unused,
>> char const *msg __maybe_unused)
>> {
>> }
>> --
>> 2.40.0.348.gf938b09366-goog
>>

2023-04-05 21:28:48

by Jiri Olsa

[permalink] [raw]
Subject: Re: [PATCH v2] perf pmu: Make parser reentrant

On Tue, Apr 04, 2023 at 06:36:30AM -0700, Ian Rogers wrote:
> By default bison uses global state for compatibility with yacc. Make
> the parser reentrant so that it may be used in asynchronous and
> multithreaded situations.
>
> Signed-off-by: Ian Rogers <[email protected]>
> ---
> tools/perf/util/pmu.c | 24 ++++++++++++++++++------
> tools/perf/util/pmu.h | 2 +-
> tools/perf/util/pmu.l | 17 ++++++++++++-----
> tools/perf/util/pmu.y | 5 ++++-
> 4 files changed, 35 insertions(+), 13 deletions(-)
>
> diff --git a/tools/perf/util/pmu.c b/tools/perf/util/pmu.c
> index 78a407b42ad1..f603cdabf797 100644
> --- a/tools/perf/util/pmu.c
> +++ b/tools/perf/util/pmu.c
> @@ -24,6 +24,8 @@
> #include "evsel.h"
> #include "pmu.h"
> #include "pmus.h"
> +#include "pmu-bison.h"
> +#include "pmu-flex.h"
> #include "parse-events.h"
> #include "print-events.h"
> #include "header.h"
> @@ -57,9 +59,6 @@ struct perf_pmu_format {
> struct list_head list;
> };
>
> -int perf_pmu_parse(struct list_head *list, char *name);
> -extern FILE *perf_pmu_in;
> -
> static bool hybrid_scanned;
>
> static struct perf_pmu *perf_pmu__find2(int dirfd, const char *name);
> @@ -81,6 +80,8 @@ int perf_pmu__format_parse(int dirfd, struct list_head *head)
> while (!ret && (evt_ent = readdir(format_dir))) {
> char *name = evt_ent->d_name;
> int fd;
> + void *scanner;
> + FILE *file;
>
> if (!strcmp(name, ".") || !strcmp(name, ".."))
> continue;
> @@ -91,9 +92,20 @@ int perf_pmu__format_parse(int dirfd, struct list_head *head)
> if (fd < 0)
> break;
>
> - perf_pmu_in = fdopen(fd, "r");
> - ret = perf_pmu_parse(head, name);
> - fclose(perf_pmu_in);
> + file = fdopen(fd, "r");
> + if (!file)
> + break;

hum, do we potentially leak fd in here?

jirka

> +
> + ret = perf_pmu_lex_init(&scanner);
> + if (ret) {
> + fclose(file);
> + break;
> + }
> +
> + perf_pmu_set_in(file, scanner);
> + ret = perf_pmu_parse(head, name, scanner);
> + perf_pmu_lex_destroy(scanner);
> + fclose(file);
> }
>
> closedir(format_dir);
> diff --git a/tools/perf/util/pmu.h b/tools/perf/util/pmu.h
> index 32c3a75bca0e..d53618c65c92 100644
> --- a/tools/perf/util/pmu.h
> +++ b/tools/perf/util/pmu.h
> @@ -206,7 +206,7 @@ int perf_pmu__check_alias(struct perf_pmu *pmu, struct list_head *head_terms,
> struct perf_pmu_info *info);
> struct list_head *perf_pmu__alias(struct perf_pmu *pmu,
> struct list_head *head_terms);
> -void perf_pmu_error(struct list_head *list, char *name, char const *msg);
> +void perf_pmu_error(struct list_head *list, char *name, void *scanner, char const *msg);
>
> int perf_pmu__new_format(struct list_head *list, char *name,
> int config, unsigned long *bits);
> diff --git a/tools/perf/util/pmu.l b/tools/perf/util/pmu.l
> index 58b4926cfaca..67b247be693b 100644
> --- a/tools/perf/util/pmu.l
> +++ b/tools/perf/util/pmu.l
> @@ -1,4 +1,6 @@
> %option prefix="perf_pmu_"
> +%option reentrant
> +%option bison-bridge
>
> %{
> #include <stdlib.h>
> @@ -6,16 +8,21 @@
> #include "pmu.h"
> #include "pmu-bison.h"
>
> -static int value(int base)
> +char *perf_pmu_get_text(yyscan_t yyscanner);
> +YYSTYPE *perf_pmu_get_lval(yyscan_t yyscanner);
> +
> +static int value(yyscan_t scanner, int base)
> {
> + YYSTYPE *yylval = perf_pmu_get_lval(scanner);
> + char *text = perf_pmu_get_text(scanner);
> long num;
>
> errno = 0;
> - num = strtoul(perf_pmu_text, NULL, base);
> + num = strtoul(text, NULL, base);
> if (errno)
> return PP_ERROR;
>
> - perf_pmu_lval.num = num;
> + yylval->num = num;
> return PP_VALUE;
> }
>
> @@ -25,7 +32,7 @@ num_dec [0-9]+
>
> %%
>
> -{num_dec} { return value(10); }
> +{num_dec} { return value(yyscanner, 10); }
> config { return PP_CONFIG; }
> - { return '-'; }
> : { return ':'; }
> @@ -35,7 +42,7 @@ config { return PP_CONFIG; }
>
> %%
>
> -int perf_pmu_wrap(void)
> +int perf_pmu_wrap(void *scanner __maybe_unused)
> {
> return 1;
> }
> diff --git a/tools/perf/util/pmu.y b/tools/perf/util/pmu.y
> index e675d79a0274..dff4e892ac4d 100644
> --- a/tools/perf/util/pmu.y
> +++ b/tools/perf/util/pmu.y
> @@ -1,6 +1,8 @@
> -
> +%define api.pure full
> %parse-param {struct list_head *format}
> %parse-param {char *name}
> +%parse-param {void *scanner}
> +%lex-param {void* scanner}
>
> %{
>
> @@ -78,6 +80,7 @@ PP_VALUE
>
> void perf_pmu_error(struct list_head *list __maybe_unused,
> char *name __maybe_unused,
> + void *scanner __maybe_unused,
> char const *msg __maybe_unused)
> {
> }
> --
> 2.40.0.348.gf938b09366-goog
>

2023-04-06 06:24:07

by Ian Rogers

[permalink] [raw]
Subject: Re: [PATCH v2] perf pmu: Make parser reentrant

On Wed, Apr 5, 2023 at 2:23 PM Jiri Olsa <[email protected]> wrote:
>
> On Tue, Apr 04, 2023 at 06:36:30AM -0700, Ian Rogers wrote:
> > By default bison uses global state for compatibility with yacc. Make
> > the parser reentrant so that it may be used in asynchronous and
> > multithreaded situations.
> >
> > Signed-off-by: Ian Rogers <[email protected]>
> > ---
> > tools/perf/util/pmu.c | 24 ++++++++++++++++++------
> > tools/perf/util/pmu.h | 2 +-
> > tools/perf/util/pmu.l | 17 ++++++++++++-----
> > tools/perf/util/pmu.y | 5 ++++-
> > 4 files changed, 35 insertions(+), 13 deletions(-)
> >
> > diff --git a/tools/perf/util/pmu.c b/tools/perf/util/pmu.c
> > index 78a407b42ad1..f603cdabf797 100644
> > --- a/tools/perf/util/pmu.c
> > +++ b/tools/perf/util/pmu.c
> > @@ -24,6 +24,8 @@
> > #include "evsel.h"
> > #include "pmu.h"
> > #include "pmus.h"
> > +#include "pmu-bison.h"
> > +#include "pmu-flex.h"
> > #include "parse-events.h"
> > #include "print-events.h"
> > #include "header.h"
> > @@ -57,9 +59,6 @@ struct perf_pmu_format {
> > struct list_head list;
> > };
> >
> > -int perf_pmu_parse(struct list_head *list, char *name);
> > -extern FILE *perf_pmu_in;
> > -
> > static bool hybrid_scanned;
> >
> > static struct perf_pmu *perf_pmu__find2(int dirfd, const char *name);
> > @@ -81,6 +80,8 @@ int perf_pmu__format_parse(int dirfd, struct list_head *head)
> > while (!ret && (evt_ent = readdir(format_dir))) {
> > char *name = evt_ent->d_name;
> > int fd;
> > + void *scanner;
> > + FILE *file;
> >
> > if (!strcmp(name, ".") || !strcmp(name, ".."))
> > continue;
> > @@ -91,9 +92,20 @@ int perf_pmu__format_parse(int dirfd, struct list_head *head)
> > if (fd < 0)
> > break;
> >
> > - perf_pmu_in = fdopen(fd, "r");
> > - ret = perf_pmu_parse(head, name);
> > - fclose(perf_pmu_in);
> > + file = fdopen(fd, "r");
> > + if (!file)
> > + break;
>
> hum, do we potentially leak fd in here?
>
> jirka

Agreed. Will fix in v3.

Thanks,
Ian

> > +
> > + ret = perf_pmu_lex_init(&scanner);
> > + if (ret) {
> > + fclose(file);
> > + break;
> > + }
> > +
> > + perf_pmu_set_in(file, scanner);
> > + ret = perf_pmu_parse(head, name, scanner);
> > + perf_pmu_lex_destroy(scanner);
> > + fclose(file);
> > }
> >
> > closedir(format_dir);
> > diff --git a/tools/perf/util/pmu.h b/tools/perf/util/pmu.h
> > index 32c3a75bca0e..d53618c65c92 100644
> > --- a/tools/perf/util/pmu.h
> > +++ b/tools/perf/util/pmu.h
> > @@ -206,7 +206,7 @@ int perf_pmu__check_alias(struct perf_pmu *pmu, struct list_head *head_terms,
> > struct perf_pmu_info *info);
> > struct list_head *perf_pmu__alias(struct perf_pmu *pmu,
> > struct list_head *head_terms);
> > -void perf_pmu_error(struct list_head *list, char *name, char const *msg);
> > +void perf_pmu_error(struct list_head *list, char *name, void *scanner, char const *msg);
> >
> > int perf_pmu__new_format(struct list_head *list, char *name,
> > int config, unsigned long *bits);
> > diff --git a/tools/perf/util/pmu.l b/tools/perf/util/pmu.l
> > index 58b4926cfaca..67b247be693b 100644
> > --- a/tools/perf/util/pmu.l
> > +++ b/tools/perf/util/pmu.l
> > @@ -1,4 +1,6 @@
> > %option prefix="perf_pmu_"
> > +%option reentrant
> > +%option bison-bridge
> >
> > %{
> > #include <stdlib.h>
> > @@ -6,16 +8,21 @@
> > #include "pmu.h"
> > #include "pmu-bison.h"
> >
> > -static int value(int base)
> > +char *perf_pmu_get_text(yyscan_t yyscanner);
> > +YYSTYPE *perf_pmu_get_lval(yyscan_t yyscanner);
> > +
> > +static int value(yyscan_t scanner, int base)
> > {
> > + YYSTYPE *yylval = perf_pmu_get_lval(scanner);
> > + char *text = perf_pmu_get_text(scanner);
> > long num;
> >
> > errno = 0;
> > - num = strtoul(perf_pmu_text, NULL, base);
> > + num = strtoul(text, NULL, base);
> > if (errno)
> > return PP_ERROR;
> >
> > - perf_pmu_lval.num = num;
> > + yylval->num = num;
> > return PP_VALUE;
> > }
> >
> > @@ -25,7 +32,7 @@ num_dec [0-9]+
> >
> > %%
> >
> > -{num_dec} { return value(10); }
> > +{num_dec} { return value(yyscanner, 10); }
> > config { return PP_CONFIG; }
> > - { return '-'; }
> > : { return ':'; }
> > @@ -35,7 +42,7 @@ config { return PP_CONFIG; }
> >
> > %%
> >
> > -int perf_pmu_wrap(void)
> > +int perf_pmu_wrap(void *scanner __maybe_unused)
> > {
> > return 1;
> > }
> > diff --git a/tools/perf/util/pmu.y b/tools/perf/util/pmu.y
> > index e675d79a0274..dff4e892ac4d 100644
> > --- a/tools/perf/util/pmu.y
> > +++ b/tools/perf/util/pmu.y
> > @@ -1,6 +1,8 @@
> > -
> > +%define api.pure full
> > %parse-param {struct list_head *format}
> > %parse-param {char *name}
> > +%parse-param {void *scanner}
> > +%lex-param {void* scanner}
> >
> > %{
> >
> > @@ -78,6 +80,7 @@ PP_VALUE
> >
> > void perf_pmu_error(struct list_head *list __maybe_unused,
> > char *name __maybe_unused,
> > + void *scanner __maybe_unused,
> > char const *msg __maybe_unused)
> > {
> > }
> > --
> > 2.40.0.348.gf938b09366-goog
> >