* Dhaval Giani <[email protected]> [2009-05-18 14:17:46]:
> 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
>
> [dha...@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
> [dha...@gondor tests]$
>
> Which is the setup on this system.
>
> Signed-off-by: Dhaval Giani <[email protected]>
> Cc: Jan Safranek <[email protected]>
>
> ---
> include/libcgroup.h | 12 ++++++
> src/api.c | 85
> +++++++++++++++++++++++++++++++++++++++++++++++++
> src/libcgroup.map | 3 +
> tests/Makefile.am | 3 +
> tests/get_controller.c | 35 ++++++++++++++++++++
> 5 files changed, 137 insertions(+), 1 deletion(-)
>
> Index: libcg/src/api.c
> ===================================================================
> --- libcg.orig/src/api.c
> +++ libcg/src/api.c
> @@ -2525,3 +2525,88 @@ int cgroup_get_task_begin(char *cgroup,
>
> return ret;
> }
> +
> +
> +int cgroup_get_controller_end(void **handle)
> +{
> + int *key = (int *) *handle;
> +
> + if (!cgroup_initialized)
> + return ECGROUPNOTINITIALIZED;
> +
> + if (!key)
> + return ECGINVAL;
> +
> + free(key);
> + *handle = NULL;
> +
> + return 0;
> +}
> +/*
> + * name and path will be allocated by the API. The caller *must* free
> + * name and path before calling into the API again else there will be
> + * leaks.
> + */
> +int cgroup_get_controller_next(void **handle, char **name, char **path)
> +{
> + int error = 0;
> + int *pos = (int *) *handle;
> + int ret = 0;
> +
> + if (!cgroup_initialized)
> + return ECGROUPNOTINITIALIZED;
> +
> + if (!pos)
> + return ECGINVAL;
> +
> + pthread_rwlock_rdlock(&cg_mount_table_lock);
> +
> + if (cg_mount_table[*pos].name[0] == '\0') {
> + ret = ECGEOF;
> + goto out_unlock;
> + }
> +
> + *name = strdup(cg_mount_table[*pos].name);
Don't like this, can't we expect API to allocate and pass a string?
> +
> + if (!*name) {
> + last_errno = errno;
> + ret = ECGOTHER;
> + goto out_unlock;
> + }
> +
> + *path = strdup(cg_mount_table[*pos].path);
> +
Ditto
> + if (!*path) {
> + last_errno = errno;
> + ret = ECGOTHER;
> + goto out_unlock;
> + }
> +
> + (*pos)++;
> + *handle = pos;
> +
> +out_unlock:
> + pthread_rwlock_unlock(&cg_mount_table_lock);
> + return ret;
> +}
> +
> +int cgroup_get_controller_begin(void **handle, char **name, char **path)
> +{
> + int *pos;
> +
> + if (!cgroup_initialized)
> + return ECGROUPNOTINITIALIZED;
> +
> + pos = malloc(sizeof(int));
> +
> + if (!pos) {
> + last_errno = errno;
> + return ECGOTHER;
> + }
> +
> + *pos = 0;
> +
> + *handle = pos;
> +
> + return cgroup_get_controller_next(handle, name, path);
> +}
> Index: libcg/include/libcgroup.h
> ===================================================================
> --- libcg.orig/include/libcgroup.h
> +++ libcg/include/libcgroup.h
> @@ -303,6 +303,18 @@ int cgroup_get_task_begin(char *cgroup,
> */
> 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, char **name, char **path);
> +int cgroup_get_controller_next(void **handle, char **name, char **path);
> +int cgroup_get_controller_end(void **handle);
> /* The wrappers for filling libcg structures */
>
> struct cgroup *cgroup_new_cgroup(const char *name);
> Index: libcg/src/libcgroup.map
> ===================================================================
> --- libcg.orig/src/libcgroup.map
> +++ libcg/src/libcgroup.map
> @@ -63,4 +63,7 @@ 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_0.33;
> Index: libcg/tests/Makefile.am
> ===================================================================
> --- libcg.orig/tests/Makefile.am
> +++ libcg/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
>
> Index: libcg/tests/get_controller.c
> ===================================================================
> --- /dev/null
> +++ libcg/tests/get_controller.c
> @@ -0,0 +1,35 @@
> +#include <libcgroup.h>
> +#include <stdio.h>
> +#include <stdlib.h>
> +
> +int main()
> +{
> + int error;
> + char *path, *name;
> + void *handle;
> +
> + error = cgroup_init();
> +
> + if (error) {
> + printf("cgroup_init failed with %s\n", cgroup_strerror(error));
> + exit(1);
> + }
> +
> + error = cgroup_get_controller_begin(&handle, &name, &path);
> +
> + while (error != ECGEOF) {
> + printf("Controller %s is mounted at %s\n", name, path);
> + free(path);
> + free(name);
> + error = cgroup_get_controller_next(&handle, &name, &path);
> + 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;
> +}
>
>
>
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