cgroups: add get_cgroup_fd() helper

Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>

diff --git a/bindings.c b/bindings.c
index 390ae5d95668962e3dd09a5d9e25c85228654c7b..6903933b4aa4d2f8d0995a072855f6022c2aa6d9 100644 (file)
--- a/bindings.c
+++ b/bindings.c
@@ -707,19 +707,6 @@ static void print_subsystems(void)
        }
 }
 
-/* do we need to do any massaging here?  I'm not sure... */
-/* Return the mounted controller and store the corresponding open file descriptor
- * referring to the controller mountpoint in the private lxcfs namespace in
- * @cfd.
- */
-static int find_mounted_controller(const char *controller)
-{
-       struct hierarchy *h;
-
-       h = cgroup_ops->get_hierarchy(cgroup_ops, controller);
-       return h ? h->fd : -EBADF;
-}
-
 bool cgfs_set_value(const char *controller, const char *cgroup, const char *file,
                const char *value)
 {
@@ -727,7 +714,7 @@ bool cgfs_set_value(const char *controller, const char *cgroup, const char *file
        size_t len;
        char *fnam;
 
-       cfd = find_mounted_controller(controller);
+       cfd = get_cgroup_fd(controller);
        if (cfd < 0)
                return false;
 
@@ -793,7 +780,7 @@ int cgfs_create(const char *controller, const char *cg, uid_t uid, gid_t gid)
        size_t len;
        char *dirnam;
 
-       cfd = find_mounted_controller(controller);
+       cfd = get_cgroup_fd(controller);
        if (cfd < 0)
                return -EINVAL;
 
@@ -884,7 +871,7 @@ bool cgfs_remove(const char *controller, const char *cg)
        char *dirnam;
        bool bret;
 
-       cfd = find_mounted_controller(controller);
+       cfd = get_cgroup_fd(controller);
        if (cfd < 0)
                return false;
 
@@ -910,7 +897,7 @@ bool cgfs_chmod_file(const char *controller, const char *file, mode_t mode)
        size_t len;
        char *pathname;
 
-       cfd = find_mounted_controller(controller);
+       cfd = get_cgroup_fd(controller);
        if (cfd < 0)
                return false;
 
@@ -947,7 +934,7 @@ int cgfs_chown_file(const char *controller, const char *file, uid_t uid, gid_t g
        size_t len;
        char *pathname;
 
-       cfd = find_mounted_controller(controller);
+       cfd = get_cgroup_fd(controller);
        if (cfd < 0)
                return false;
 
@@ -973,7 +960,7 @@ FILE *open_pids_file(const char *controller, const char *cgroup)
        size_t len;
        char *pathname;
 
-       cfd = find_mounted_controller(controller);
+       cfd = get_cgroup_fd(controller);
        if (cfd < 0)
                return false;
 
@@ -1003,7 +990,7 @@ static bool cgfs_iterate_cgroup(const char *controller, const char *cgroup, bool
        struct dirent *dirent;
        DIR *dir;
 
-       cfd = find_mounted_controller(controller);
+       cfd = get_cgroup_fd(controller);
        *list = NULL;
        if (cfd < 0)
                return false;
@@ -1106,7 +1093,7 @@ bool cgfs_param_exist(const char *controller, const char *cgroup, const char *fi
        size_t len;
        char *fnam;
 
-       cfd = find_mounted_controller(controller);
+       cfd = get_cgroup_fd(controller);
        if (cfd < 0)
                return false;
 
@@ -1130,7 +1117,7 @@ struct cgfs_files *cgfs_get_key(const char *controller, const char *cgroup, cons
        struct stat sb;
        struct cgfs_files *newkey;
 
-       cfd = find_mounted_controller(controller);
+       cfd = get_cgroup_fd(controller);
        if (cfd < 0)
                return false;
 
@@ -1193,7 +1180,7 @@ bool is_child_cgroup(const char *controller, const char *cgroup, const char *f)
        int ret;
        struct stat sb;
 
-       cfd = find_mounted_controller(controller);
+       cfd = get_cgroup_fd(controller);
        if (cfd < 0)
                return false;
 
@@ -1553,7 +1540,7 @@ char *get_pid_cgroup(pid_t pid, const char *contrl)
 {
        int cfd;
 
-       cfd = find_mounted_controller(contrl);
+       cfd = get_cgroup_fd(contrl);
        if (cfd < 0)
                return false;
 
@@ -5578,7 +5565,7 @@ static int proc_loadavg_read(char *buf, size_t size, off_t offset,
 
        /* First time */
        if (n == NULL) {
-               cfd = find_mounted_controller("cpu");
+               cfd = get_cgroup_fd("cpu");
                if (cfd >= 0) {
                        /*
                         * In locate_node() above, pthread_rwlock_unlock() isn't used

diff --git a/cgroups/cgroup.h b/cgroups/cgroup.h
index e84233b622655c21a61b8174f2ed236ca6d549a2..c1fc56043ade117ffd754cc17a9791ac1d5ba225 100644 (file)
--- a/cgroups/cgroup.h
+++ b/cgroups/cgroup.h
@@ -3,6 +3,7 @@
 #ifndef __LXC_CGROUP_H
 #define __LXC_CGROUP_H
 
+#include <errno.h>
 #include <stdbool.h>
 #include <stddef.h>
 #include <sys/types.h>
@@ -184,4 +185,12 @@ static inline bool is_unified_controller(int version)
        return version == CGROUP2_SUPER_MAGIC;
 }
 
+static inline int get_cgroup_fd(const char *controller)
+{
+       struct hierarchy *h;
+
+       h = cgroup_ops->get_hierarchy(cgroup_ops, controller);
+       return h ? h->fd : -EBADF;
+}
+
 #endif