[PATCH V3 4/6] perf tools: add perf_data_file__open_tmp

[kan.liang@intel.com]

From: Kan Liang <Kan.liang@intel.com>

And an interface for perf_data_file to open tmp file.
Automatically generate the tmp file name if it's not assigned. The name
cannot be const char. Introduce char *tmp_path for it.
The tmp file will be deleted after close.

It will be used as per-thread file to temporarily store event synthesizd
result in the following patch.

Signed-off-by: Kan Liang <Kan.liang@intel.com>
---
 tools/perf/util/data.c | 26 ++++++++++++++++++++++++++
 tools/perf/util/data.h |  2 ++
 2 files changed, 28 insertions(+)

diff --git a/tools/perf/util/data.c b/tools/perf/util/data.c
index 1123b30..cd6fdf9 100644
--- a/tools/perf/util/data.c
+++ b/tools/perf/util/data.c
@@ -139,9 +139,35 @@ int perf_data_file__open(struct perf_data_file *file)
 	return open_file(file);
 }
 
+int perf_data_file__open_tmp(struct perf_data_file *file)
+{
+	int fd;
+
+	if (!file->tmp_path &&
+	    (asprintf(&file->tmp_path, "perf.tmp.XXXXXX") < 0))
+		goto err;
+
+	fd = mkstemp(file->tmp_path);
+	if (fd < 0) {
+		free(file->tmp_path);
+		goto err;
+	}
+
+	file->fd = fd;
+	return 0;
+err:
+	file->tmp_path = NULL;
+	return -1;
+}
+
 void perf_data_file__close(struct perf_data_file *file)
 {
 	close(file->fd);
+	if (file->tmp_path) {
+		unlink(file->tmp_path);
+		free(file->tmp_path);
+		file->tmp_path = NULL;
+	}
 }
 
 ssize_t perf_data_file__write(struct perf_data_file *file,
diff --git a/tools/perf/util/data.h b/tools/perf/util/data.h
index ae510ce..892b3d5 100644
--- a/tools/perf/util/data.h
+++ b/tools/perf/util/data.h
@@ -10,6 +10,7 @@ enum perf_data_mode {
 
 struct perf_data_file {
 	const char		*path;
+	char			*tmp_path;
 	int			 fd;
 	bool			 is_pipe;
 	bool			 force;
@@ -43,6 +44,7 @@ static inline unsigned long perf_data_file__size(struct perf_data_file *file)
 }
 
 int perf_data_file__open(struct perf_data_file *file);
+int perf_data_file__open_tmp(struct perf_data_file *file);
 void perf_data_file__close(struct perf_data_file *file);
 ssize_t perf_data_file__write(struct perf_data_file *file,
 			      void *buf, size_t size);
-- 
2.7.4