From e4f9ba367252bfb521878133124c51711ce687e7 Mon Sep 17 00:00:00 2001
From: Jan Safranek <jsafrane@redhat.com>
Date: Wed, 6 Apr 2011 08:37:11 +0200
Subject: [PATCH] Added iterators to go through all mount points of a
 hierarchy.

Add new iterators, which return all mount points of given hierarchy. The order
of the mount points is the same as in /proc/mounts, The first returned mount
point is the same as cgroup_get_subsys_mount_point().

Signed-off-by: Jan Safranek <jsafrane@redhat.com>
Acked-by: Ivana Hutarova Varekova<varekova@redhat.com>
---
 include/libcgroup/init.h      |  3 ++
 include/libcgroup/iterators.h | 34 ++++++++++++++++++++
 src/api.c                     | 59 +++++++++++++++++++++++++++++++++++
 src/libcgroup.map             |  7 +++++
 4 files changed, 103 insertions(+)

diff --git a/include/libcgroup/init.h b/include/libcgroup/init.h
index 881b8302..37090965 100644
--- a/include/libcgroup/init.h
+++ b/include/libcgroup/init.h
@@ -41,6 +41,9 @@ int cgroup_init(void);
 /**
  * Returns path where is mounted given controller. Applications should rely on
  * @c libcgroup API and not call this function directly.
+ * Only the first mount point is returned, use
+ * cgroup_get_subsys_mount_point_begin(), cgroup_get_subsys_mount_point_next()
+ * and cgroup_get_subsys_mount_point_end() to get all of them.
  * @param controller Name of the controller
  * @param mount_point The string where the mount point location is stored.
  * 	Please note, the caller must free the mount_point.
diff --git a/include/libcgroup/iterators.h b/include/libcgroup/iterators.h
index 8ecc53f5..c6d453d6 100644
--- a/include/libcgroup/iterators.h
+++ b/include/libcgroup/iterators.h
@@ -385,10 +385,44 @@ int cgroup_get_all_controller_next(void **handle, struct controller_data *info);
  */
 int cgroup_get_all_controller_end(void **handle);
 
+/**
+ * @}
+ *
+ * @name List all mount points of a controller.
+ * Use following functions to list all mount points of a hierarchy with given
+ * controller.
+ */
+
+/**
+ * Read the first mount point of the hierarchy with given controller.
+ * The first is the same as the mount point returned by
+ * cgroup_get_subsys_mount_point().
+ * @param handle Handle to be used for iteration.
+ * @param controller Controller name.
+ * @param path Buffer to fill the path into. The buffer must be at least
+ * FILENAME_MAX characters long.
+ */
+int cgroup_get_subsys_mount_point_begin(const char *controller, void **handle,
+		char *path);
+/**
+ * Read next mount point of the hierarchy with given controller.
+ * @param handle Handle to be used for iteration.
+ * @param path Buffer to fill the path into. The buffer must be at least
+ * FILENAME_MAX characters long.
+ */
+int cgroup_get_subsys_mount_point_next(void **handle,
+		char *path);
+
+/**
+ * Release the iterator.
+ */
+int cgroup_get_subsys_mount_point_end(void **handle);
+
 /**
  * @}
  * @}
  */
+
 __END_DECLS
 
 #endif /* _LIBCGROUP_ITERATORS_H */
diff --git a/src/api.c b/src/api.c
index 0dc135ab..dfc70a49 100644
--- a/src/api.c
+++ b/src/api.c
@@ -3922,3 +3922,62 @@ void cgroup_dictionary_iterator_end(void **handle)
 	*handle = NULL;
 }
 
+int cgroup_get_subsys_mount_point_begin(const char *controller, void **handle,
+		char *path)
+{
+	int i;
+
+	if (!cgroup_initialized)
+		return ECGROUPNOTINITIALIZED;
+	if (!handle || !path || !controller)
+		return ECGINVAL;
+
+
+	for (i = 0; cg_mount_table[i].name[0] != '\0'; i++)
+		if (strcmp(controller, cg_mount_table[i].name) == 0)
+			break;
+
+	if (cg_mount_table[i].name[0] == '\0') {
+		/* the controller is not mounted at all */
+		*handle = NULL;
+		*path = '\0';
+		return ECGEOF;
+	}
+
+	/*
+	 * 'handle' is pointer to struct cg_mount_point, which should be
+	 * returned next.
+	 */
+	*handle = cg_mount_table[i].mount.next;
+	strcpy(path, cg_mount_table[i].mount.path);
+	return 0;
+}
+
+int cgroup_get_subsys_mount_point_next(void **handle,
+		char *path)
+{
+	struct cg_mount_point *it;
+
+	if (!cgroup_initialized)
+		return ECGROUPNOTINITIALIZED;
+	if (!handle || !path)
+		return ECGINVAL;
+
+	it = *handle;
+	if (!it) {
+		*handle = NULL;
+		*path = '\0';
+		return ECGEOF;
+	}
+
+	*handle = it->next;
+	strcpy(path, it->path);
+	return 0;
+}
+
+int cgroup_get_subsys_mount_point_end(void **handle)
+{
+	return 0;
+}
+
+
diff --git a/src/libcgroup.map b/src/libcgroup.map
index 2a3439f3..fb30801d 100644
--- a/src/libcgroup.map
+++ b/src/libcgroup.map
@@ -96,3 +96,10 @@ CGROUP_0.37 {
 	cgroup_read_value_end;
 	cg_chmod_recursive;
 } CGROUP_0.36;
+
+CGROUP_0.38 {
+       cgroup_get_subsys_mount_point_begin;
+       cgroup_get_subsys_mount_point_next;
+       cgroup_get_subsys_mount_point_end;
+} CGROUP_0.37;
+
-- 
2.47.2