perf data: Add perf_data__open_dir_data function

Add perf_data__open_dir_data to open files inside 'struct perf_data'
path directory:

   static int perf_data__open_dir(struct perf_data *data);

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Alexey Budankov <alexey.budankov@linux.intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/r/20190224190656.30163-10-jolsa@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/util/data.c

@@ -8,6 +8,8 @@
 #include <unistd.h>
 #include <string.h>
 #include <asm/bug.h>
+#include <sys/types.h>
+#include <dirent.h>
 
 #include "data.h"
 #include "util.h"
@@ -59,6 +61,63 @@ int perf_data__create_dir(struct perf_data *data, int nr)
 	return ret;
 }
 
+int perf_data__open_dir(struct perf_data *data)
+{
+	struct perf_data_file *files = NULL;
+	struct dirent *dent;
+	int ret = -1;
+	DIR *dir;
+	int nr = 0;
+
+	dir = opendir(data->path);
+	if (!dir)
+		return -EINVAL;
+
+	while ((dent = readdir(dir)) != NULL) {
+		struct perf_data_file *file;
+		char path[PATH_MAX];
+		struct stat st;
+
+		snprintf(path, sizeof(path), "%s/%s", data->path, dent->d_name);
+		if (stat(path, &st))
+			continue;
+
+		if (!S_ISREG(st.st_mode) || strncmp(dent->d_name, "data", 4))
+			continue;
+
+		ret = -ENOMEM;
+
+		file = realloc(files, (nr + 1) * sizeof(*files));
+		if (!file)
+			goto out_err;
+
+		files = file;
+		file = &files[nr++];
+
+		file->path = strdup(path);
+		if (!file->path)
+			goto out_err;
+
+		ret = open(file->path, O_RDONLY);
+		if (ret < 0)
+			goto out_err;
+
+		file->fd = ret;
+		file->size = st.st_size;
+	}
+
+	if (!files)
+		return -EINVAL;
+
+	data->dir.files = files;
+	data->dir.nr    = nr;
+	return 0;
+
+out_err:
+	close_dir(files, nr);
+	return ret;
+}
+
 static bool check_pipe(struct perf_data *data)
 {
 	struct stat st;

tools/perf/util/data.h

@@ -71,5 +71,6 @@ int perf_data__switch(struct perf_data *data,
 			   size_t pos, bool at_exit);
 
 int perf_data__create_dir(struct perf_data *data, int nr);
+int perf_data__open_dir(struct perf_data *data);
 void perf_data__close_dir(struct perf_data *data);
 #endif /* __PERF_DATA_H */