From: Dhaval Giani Date: Thu, 18 Jun 2009 14:12:48 +0000 (+0530) Subject: libcgroup: Introduce get_controller API X-Git-Tag: v0.34~26 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=3ee2b056852a65bc7a3128ef924f1ae83573016e;p=thirdparty%2Flibcgroup.git 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 Cc: Jan Safranek Acked-by: Bharata B Rao --- diff --git a/include/libcgroup.h b/include/libcgroup.h index dd87c638..e2abdc87 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 ab35ed7c..63813a3d 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//status file. * @param pid: The process id diff --git a/src/libcgroup.map b/src/libcgroup.map index 0748bb34..adcf9059 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 41aebd3b..e8401f22 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 00000000..1829f5cc --- /dev/null +++ b/tests/get_controller.c @@ -0,0 +1,34 @@ +#include +#include +#include + +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; +}