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authorDhaval Giani <dhaval@linux.vnet.ibm.com>2009-06-18 19:42:48 +0530
committerDhaval Giani <dhaval@linux.vnet.ibm.com>2009-06-18 19:49:40 +0530
commit3ee2b056852a65bc7a3128ef924f1ae83573016e (patch)
tree04841d70bdd5722f8fd88e0c7a0b42db5002b65b
parent80e9084d3e7be7fbec1ed72f90b88c7626fb93d1 (diff)
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libcgroup: Introduce get_controller API
This set of APIs will allow the caller to query the mount table and find out what controller is mounted at what path. Test program has been included in the patch. Running the test program results in [dhaval@gondor tests]$ ../libtool --mode=execute ./get_controller Controller cpu is mounted at /cgroup Controller cpuacct is mounted at /cgroup Controller memory is mounted at /cgroup1 [dhaval@gondor tests]$ Which is the setup on this system. Changes from v2 1. Remove the incorrect comments as pointed out by Bharata Changes from v1 1. Use a new structure as mentioned by bharata to return the values. Signed-off-by: Dhaval Giani <dhaval@linux.vnet.ibm.com> Cc: Jan Safranek <jsafrane@redhat.com> Acked-by: Bharata B Rao <bharata@linux.vnet.ibm.com>
-rw-r--r--include/libcgroup.h21
-rw-r--r--src/api.c74
-rw-r--r--src/libcgroup.map3
-rw-r--r--tests/Makefile.am3
-rw-r--r--tests/get_controller.c34
5 files changed, 134 insertions, 1 deletions
diff --git a/include/libcgroup.h b/include/libcgroup.h
index dd87c63..e2abdc8 100644
--- a/include/libcgroup.h
+++ b/include/libcgroup.h
@@ -134,6 +134,11 @@ struct cgroup_stat {
char value[CG_VALUE_MAX];
};
+struct cgroup_mount_point {
+ char name[FILENAME_MAX];
+ char path[FILENAME_MAX];
+};
+
/* Functions and structures that can be used by the application*/
struct cgroup;
struct cgroup_controller;
@@ -303,6 +308,22 @@ int cgroup_get_task_begin(char *cgroup, char *controller, void **handle,
*/
int cgroup_get_task_next(void **handle, pid_t *pid);
int cgroup_get_task_end(void **handle);
+
+/**
+ * Read the mount table to give a list where each controller is
+ * mounted
+ * @handle: Handle to be used for iteration.
+ * @name: The variable where the name is stored. Should be freed by caller.
+ * @path: Te variable where the path to the controller is stored. Should be
+ * freed by the caller.
+ */
+int cgroup_get_controller_begin(void **handle, struct cgroup_mount_point *info);
+/*
+ * While walking through the mount table, the controllers will be
+ * returned in order of their mount points.
+ */
+int cgroup_get_controller_next(void **handle, struct cgroup_mount_point *info);
+int cgroup_get_controller_end(void **handle);
/* The wrappers for filling libcg structures */
struct cgroup *cgroup_new_cgroup(const char *name);
diff --git a/src/api.c b/src/api.c
index ab35ed7..63813a3 100644
--- a/src/api.c
+++ b/src/api.c
@@ -2541,6 +2541,80 @@ int cgroup_get_task_begin(char *cgroup, char *controller, void **handle,
return ret;
}
+
+int cgroup_get_controller_end(void **handle)
+{
+ int *pos = (int *) *handle;
+
+ if (!cgroup_initialized)
+ return ECGROUPNOTINITIALIZED;
+
+ if (!pos)
+ return ECGINVAL;
+
+ free(pos);
+ *handle = NULL;
+
+ return 0;
+}
+
+int cgroup_get_controller_next(void **handle, struct cgroup_mount_point *info)
+{
+ int *pos = (int *) *handle;
+ int ret = 0;
+
+ if (!cgroup_initialized)
+ return ECGROUPNOTINITIALIZED;
+
+ if (!pos)
+ return ECGINVAL;
+
+ if (!info)
+ return ECGINVAL;
+
+ pthread_rwlock_rdlock(&cg_mount_table_lock);
+
+ if (cg_mount_table[*pos].name[0] == '\0') {
+ ret = ECGEOF;
+ goto out_unlock;
+ }
+
+ strncpy(info->name, cg_mount_table[*pos].name, FILENAME_MAX);
+
+ strncpy(info->path, cg_mount_table[*pos].path, FILENAME_MAX);
+
+ (*pos)++;
+ *handle = pos;
+
+out_unlock:
+ pthread_rwlock_unlock(&cg_mount_table_lock);
+ return ret;
+}
+
+int cgroup_get_controller_begin(void **handle, struct cgroup_mount_point *info)
+{
+ int *pos;
+
+ if (!cgroup_initialized)
+ return ECGROUPNOTINITIALIZED;
+
+ if (!info)
+ return ECGINVAL;
+
+ pos = malloc(sizeof(int));
+
+ if (!pos) {
+ last_errno = errno;
+ return ECGOTHER;
+ }
+
+ *pos = 0;
+
+ *handle = pos;
+
+ return cgroup_get_controller_next(handle, info);
+}
+
/**
* Get process data (euid and egid) from /proc/<pid>/status file.
* @param pid: The process id
diff --git a/src/libcgroup.map b/src/libcgroup.map
index 0748bb3..adcf905 100644
--- a/src/libcgroup.map
+++ b/src/libcgroup.map
@@ -63,6 +63,9 @@ global:
cgroup_read_stats_next;
cgroup_read_stats_end;
cgroup_walk_tree_set_flags;
+ cgroup_get_controller_end;
+ cgroup_get_controller_next;
+ cgroup_get_controller_begin;
cgroup_get_controller;
cgroup_get_uid_gid_from_procfs;
} CGROUP_0.33;
diff --git a/tests/Makefile.am b/tests/Makefile.am
index 41aebd3..e8401f2 100644
--- a/tests/Makefile.am
+++ b/tests/Makefile.am
@@ -2,7 +2,7 @@ INCLUDES = -I$(top_srcdir)/include
LDADD = $(top_srcdir)/src/.libs/libcgroup.la
# compile the tests, but do not install them
-noinst_PROGRAMS = libcgrouptest01 libcg_ba setuid pathtest walk_test read_stats walk_task
+noinst_PROGRAMS = libcgrouptest01 libcg_ba setuid pathtest walk_test read_stats walk_task get_controller
libcgrouptest01_SOURCES=libcgrouptest01.c test_functions.c libcgrouptest.h
libcg_ba_SOURCES=libcg_ba.cpp
@@ -11,6 +11,7 @@ pathtest_SOURCES=pathtest.c
walk_test_SOURCES=walk_test.c
read_stats_SOURCES=read_stats.c
walk_task_SOURCES=walk_task.c
+get_controller_SOURCES=get_controller.c
EXTRA_DIST = pathtest.sh runlibcgrouptest.sh
diff --git a/tests/get_controller.c b/tests/get_controller.c
new file mode 100644
index 0000000..1829f5c
--- /dev/null
+++ b/tests/get_controller.c
@@ -0,0 +1,34 @@
+#include <libcgroup.h>
+#include <stdio.h>
+#include <stdlib.h>
+
+int main()
+{
+ int error;
+ void *handle;
+ struct cgroup_mount_point info;
+
+ error = cgroup_init();
+
+ if (error) {
+ printf("cgroup_init failed with %s\n", cgroup_strerror(error));
+ exit(1);
+ }
+
+ error = cgroup_get_controller_begin(&handle, &info);
+
+ while (error != ECGEOF) {
+ printf("Controller %s is mounted at %s\n", info.name,
+ info.path);
+ error = cgroup_get_controller_next(&handle, &info);
+ if (error && error != ECGEOF) {
+ printf("cgroup_get_contrller_next failed with %s",
+ cgroup_strerror(error));
+ exit(1);
+ }
+ }
+
+ error = cgroup_get_controller_end(&handle);
+
+ return 0;
+}