[RFC PATCH perf/core v3 04/17] perf: Add lsdir to read a directory

[Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>]

As a utility function, add lsdir() which reads given
directory and store entry name into a strlist.
lsdir accepts a filter function so that user can
filter out unneeded entries.

Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
---
 tools/perf/util/util.c |   34 ++++++++++++++++++++++++++++++++++
 tools/perf/util/util.h |    4 ++++
 2 files changed, 38 insertions(+)

diff --git a/tools/perf/util/util.c b/tools/perf/util/util.c
index f7adf12..7e74bbe 100644
--- a/tools/perf/util/util.c
+++ b/tools/perf/util/util.c
@@ -115,6 +115,40 @@ int rm_rf(char *path)
 	return rmdir(path);
 }
 
+/* A filter which removes dot files */
+bool lsdir_no_dot_filter(const char *dirname __maybe_unused, struct dirent *d)
+{
+	return d->d_name[0] != '.';
+}
+
+/* lsdir reads a directory and store it in strlist */
+struct strlist *lsdir(const char *dirname,
+		      bool (*filter)(const char *, struct dirent *))
+{
+	struct strlist *list = NULL;
+	DIR *dir;
+	struct dirent *d;
+
+	dir = opendir(dirname);
+	if (!dir)
+		return NULL;
+
+	list = strlist__new(NULL, NULL);
+	if (!list) {
+		errno = -ENOMEM;
+		goto out;
+	}
+
+	while ((d = readdir(dir)) != NULL) {
+		if (!filter || filter(dirname, d))
+			strlist__add(list, d->d_name);
+	}
+
+out:
+	closedir(dir);
+	return list;
+}
+
 static int slow_copyfile(const char *from, const char *to)
 {
 	int err = -1;
diff --git a/tools/perf/util/util.h b/tools/perf/util/util.h
index 88a8915..0236898 100644
--- a/tools/perf/util/util.h
+++ b/tools/perf/util/util.h
@@ -79,6 +79,7 @@
 #include <termios.h>
 #include <linux/bitops.h>
 #include <termios.h>
+#include "strlist.h"
 
 extern const char *graph_line;
 extern const char *graph_dotted_line;
@@ -250,6 +251,9 @@ static inline int sane_case(int x, int high)
 
 int mkdir_p(char *path, mode_t mode);
 int rm_rf(char *path);
+struct strlist *lsdir(const char *dirname,
+		      bool (*filter)(const char *, struct dirent *));
+bool lsdir_no_dot_filter(const char *dirname __maybe_unused, struct dirent *d);
 int copyfile(const char *from, const char *to);
 int copyfile_mode(const char *from, const char *to, mode_t mode);
 int copyfile_offset(int fromfd, loff_t from_ofs, int tofd, loff_t to_ofs, u64 size);