[PATCH v6 09/59] perf data: Add open flag

Ian Rogers
2026-04-25T17:49:40Z

Avoid double opens and ensure only open files are closed. This
addresses some issues with python integration where the data file
wants to be opened before being given to a session.

Assisted-by: Gemini:gemini-3.1-pro-preview
Signed-off-by: Ian Rogers <irogers@google.com>
---
Changes in v2:

1. Fixed File Rotation: In perf_data__switch() , I added data->open =
false; after the file is closed. This ensures that the subsequent
perf_data__open() call will not exit early and will successfully
open the new file.

2. Fixed Memory Leak: In open_dir() , I added a call to
zfree(&data->file.path) if mkdir() fails, preventing the leak of
the path string.
---
tools/perf/util/data.c | 26 ++++++++++++++++++++++----
tools/perf/util/data.h | 4 +++-
2 files changed, 25 insertions(+), 5 deletions(-)

diff --git a/tools/perf/util/data.c b/tools/perf/util/data.c
index 94dc534a7386..17baf71897d1 100644
--- a/tools/perf/util/data.c
+++ b/tools/perf/util/data.c
@@ -346,8 +346,10 @@ static int open_dir(struct perf_data *data)
return -1;

if (perf_data__is_write(data) &&
- mkdir(data->path, S_IRWXU) < 0)
+ mkdir(data->path, S_IRWXU) < 0) {
+ zfree(&data->file.path);
return -1;
+ }

ret = open_file(data);

@@ -360,9 +362,16 @@ static int open_dir(struct perf_data *data)

int perf_data__open(struct perf_data *data)
{
- if (check_pipe(data))
+ int ret;
+
+ if (data->open)
return 0;

+ if (check_pipe(data)) {
+ data->open = true;
+ return 0;
+ }
+
/* currently it allows stdio for pipe only */
data->file.use_stdio = false;

@@ -375,16 +384,24 @@ int perf_data__open(struct perf_data *data)
if (perf_data__is_read(data))
data->is_dir = is_dir(data);

- return perf_data__is_dir(data) ?
- open_dir(data) : open_file_dup(data);
+ ret = perf_data__is_dir(data) ? open_dir(data) : open_file_dup(data);
+
+ if (!ret)
+ data->open = true;
+
+ return ret;
}

void perf_data__close(struct perf_data *data)
{
+ if (!data->open)
+ return;
+
if (perf_data__is_dir(data))
perf_data__close_dir(data);

perf_data_file__close(&data->file);
+ data->open = false;
}

static ssize_t perf_data_file__read(struct perf_data_file *file, void *buf, size_t size)
@@ -457,6 +474,7 @@ int perf_data__switch(struct perf_data *data,

if (!at_exit) {
perf_data_file__close(&data->file);
+ data->open = false;
ret = perf_data__open(data);
if (ret < 0)
goto out;
diff --git a/tools/perf/util/data.h b/tools/perf/util/data.h
index 8299fb5fa7da..76f57f60361f 100644
--- a/tools/perf/util/data.h
+++ b/tools/perf/util/data.h
@@ -50,6 +50,8 @@ struct perf_data {
const char *path;
/** @file: Underlying file to be used. */
struct perf_data_file file;
+ /** @open: Has the file or directory been opened. */
+ bool open;
/** @is_pipe: Underlying file is a pipe. */
bool is_pipe;
/** @is_dir: Underlying file is a directory. */
@@ -59,7 +61,7 @@ struct perf_data {
/** @in_place_update: A file opened for reading but will be written to. */
bool in_place_update;
/** @mode: Read or write mode. */
- enum perf_data_mode mode;
+ enum perf_data_mode mode:8;

struct {
/** @version: perf_dir_version. */
--
2.54.0.545.g6539524ca2-goog