From a32b08930f1828b39d6cafd2779bdab66aebc484 Mon Sep 17 00:00:00 2001
From: Dhaval Giani <dhaval@linux.vnet.ibm.com>
Date: Thu, 18 Jun 2009 19:42:45 +0530
Subject: libcgroup: Add flags to the walk_tree handle

Introduce a cgroup_tree_handle structure so that we can track flags for
the walk_tree operation. In a number of cases we would prefer to walk the
tree in postorder as opposed to pre-order which is the current default.
This patch does the addition.

Changes since V1:
1. Added checks for !handle as suggested by Bharata

Signed-off-by: Dhaval Giani <dhaval@linux.vnet.ibm.com>
Acked-by: Balbir Singh <balbir@linux.vnet.ibm.com>
Acked-by: Bharata B Rao <bharata@linux.vnet.ibm.com>
---
 include/libcgroup.h      | 10 ++++++++
 src/api.c                | 60 ++++++++++++++++++++++++++++++++++++++++--------
 src/libcgroup-internal.h |  9 ++++++++
 3 files changed, 69 insertions(+), 10 deletions(-)

diff --git a/include/libcgroup.h b/include/libcgroup.h
index c526f58..149a560 100644
--- a/include/libcgroup.h
+++ b/include/libcgroup.h
@@ -255,6 +255,16 @@ int cgroup_walk_tree_next(const int depth, void **handle,
 				struct cgroup_file_info *info, int base_level);
 int cgroup_walk_tree_end(void **handle);
 
+/**
+ * This API is used to set the flags for walk_tree API. Currently availble
+ *  flags are
+ *
+ *  CGROUP_WALK_TYPE_PRE_DIR
+ *  CGROUP_WALK_TYPE_POST_DIR
+ *
+ */
+int cgroup_walk_tree_set_flags(void **handle, int flags);
+
 /**
  * Read the statistics values for the specified controller
  * @controller: Name of the controller for which stats are requested.
diff --git a/src/api.c b/src/api.c
index 4de06a3..f746bb2 100644
--- a/src/api.c
+++ b/src/api.c
@@ -2256,7 +2256,7 @@ int cgroup_walk_tree_next(const int depth, void **handle,
 				struct cgroup_file_info *info, int base_level)
 {
 	int ret = 0;
-	FTS *fts = *(FTS **)handle;
+	struct cgroup_tree_handle *entry;
 	FTSENT *ent;
 
 	if (!cgroup_initialized)
@@ -2264,26 +2264,34 @@ int cgroup_walk_tree_next(const int depth, void **handle,
 
 	if (!handle)
 		return ECGINVAL;
-	ent = fts_read(fts);
+
+	entry = (struct cgroup_tree_handle *) *handle;
+
+	ent = fts_read(entry->fts);
 	if (!ent)
 		return ECGEOF;
 	if (!base_level && depth)
 		base_level = ent->fts_level + depth;
-	ret = cg_walk_node(fts, ent, base_level, info);
-	*handle = fts;
+	ret = cg_walk_node(entry->fts, ent, base_level, info);
+	*handle = entry;
 	return ret;
 }
 
 int cgroup_walk_tree_end(void **handle)
 {
-	FTS *fts = *(FTS **)handle;
+	struct cgroup_tree_handle *entry;
 
 	if (!cgroup_initialized)
 		return ECGROUPNOTINITIALIZED;
 
 	if (!handle)
 		return ECGINVAL;
-	fts_close(fts);
+
+	entry = (struct cgroup_tree_handle *) *handle;
+
+	fts_close(entry->fts);
+	free(entry);
+	*handle = NULL;
 	return 0;
 }
 
@@ -2300,31 +2308,63 @@ int cgroup_walk_tree_begin(char *controller, char *base_path, const int depth,
 	char full_path[FILENAME_MAX];
 	FTSENT *ent;
 	FTS *fts;
+	struct cgroup_tree_handle *entry;
 
 	if (!cgroup_initialized)
 		return ECGROUPNOTINITIALIZED;
 
+	if (!handle)
+		return ECGINVAL;
+
 	if (!cg_build_path(base_path, full_path, controller))
 		return ECGOTHER;
 
+	entry = calloc(sizeof(struct cgroup_tree_handle), 1);
+
+	if (!entry) {
+		last_errno = errno;
+		return ECGOTHER;
+	}
+
 	*base_level = 0;
 	cg_path[0] = full_path;
 	cg_path[1] = NULL;
 
-	fts = fts_open(cg_path, FTS_LOGICAL | FTS_NOCHDIR |
+	entry->fts = fts_open(cg_path, FTS_LOGICAL | FTS_NOCHDIR |
 				FTS_NOSTAT, NULL);
-	ent = fts_read(fts);
+	ent = fts_read(entry->fts);
 	if (!ent) {
 		cgroup_dbg("fts_read failed\n");
 		return ECGINVAL;
 	}
 	if (!*base_level && depth)
 		*base_level = ent->fts_level + depth;
-	ret = cg_walk_node(fts, ent, *base_level, info);
-	*handle = fts;
+	ret = cg_walk_node(entry->fts, ent, *base_level, info);
+	*handle = entry;
 	return ret;
 }
 
+int cgroup_walk_tree_set_flags(void **handle, int flags)
+{
+	struct cgroup_tree_handle *entry;
+
+	if (!cgroup_initialized)
+		return ECGROUPNOTINITIALIZED;
+
+	if (!handle)
+		return ECGINVAL;
+
+	if ((flags & CGROUP_WALK_TYPE_PRE_DIR) &&
+			(flags & CGROUP_WALK_TYPE_POST_DIR))
+		return ECGINVAL;
+
+	entry = (struct cgroup_tree_handle *) *handle;
+	entry->flags = flags;
+
+	*handle = entry;
+	return 0;
+}
+
 /*
  * This parses a stat line which is in the form of (name value) pair
  * separated by a space.
diff --git a/src/libcgroup-internal.h b/src/libcgroup-internal.h
index 705ac88..95ff76c 100644
--- a/src/libcgroup-internal.h
+++ b/src/libcgroup-internal.h
@@ -19,8 +19,11 @@
 __BEGIN_DECLS
 
 #include "config.h"
+#include <fts.h>
 #include <libcgroup.h>
 #include <limits.h>
+#include <sys/stat.h>
+#include <sys/types.h>
 
 #define CGRULES_CONF_FILE       "/etc/cgrules.conf"
 #define CGRULES_MAX_FIELDS_PER_LINE		3
@@ -87,6 +90,12 @@ struct cgroup_rule_list {
 	int len;
 };
 
+/*The walk_tree handle */
+struct cgroup_tree_handle {
+	FTS *fts;
+	int flags;
+};
+
 
 /* Internal API */
 char *cg_build_path(char *name, char *path, char *type);
-- 
cgit