api.c: Refactor cgroup v1 logic in cgroup_init()

In preparation for adding support for cgroup v2, this commit
moves the cgroup v1 mount logic out of cgroup_init() and into
its own function.  No functional changes were made.

Signed-off-by: Tom Hromatka <tom.hromatka@oracle.com>
Acked-by: Dhaval Giani <dhaval.giani@oracle.com>

diff --git a/src/api.c b/src/api.c
index 24ae48d359117de1022b6758368b120626b0d734..3845352f07cfd6f51878d596d2fefa9cdc48948a 100644 (file)
--- a/src/api.c
+++ b/src/api.c
@@ -1033,6 +1033,120 @@ int cg_add_duplicate_mount(struct cg_mount_table_s *item, const char *path)
        return 0;
 }
 
+/**
+ * Process a cgroup v1 mount and add it to cg_mount_table if it's not a
+ * duplicate.
+ *
+ *     @param controllers List of controllers from /proc/cgroups
+ *     @param ent File system description of cgroup mount being processed
+ *     @param mnt_tbl_idx cg_mount_table index
+ */
+static int cgroup_process_v1_mnt(char *controllers[], struct mntent *ent,
+                                int *mnt_tbl_idx)
+{
+       char *strtok_buffer = NULL, *mntopt = NULL;
+       int duplicate = 0;
+       int i, j, ret = 0;
+
+       for (i = 0; controllers[i] != NULL; i++) {
+               mntopt = hasmntopt(ent, controllers[i]);
+
+               if (!mntopt)
+                       continue;
+
+               cgroup_dbg("found %s in %s\n", controllers[i], ent->mnt_opts);
+
+               /* do not have duplicates in mount table */
+               duplicate = 0;
+               for  (j = 0; j < *mnt_tbl_idx; j++) {
+                       if (strncmp(controllers[i],
+                                   cg_mount_table[j].name,
+                                   FILENAME_MAX) == 0) {
+                               duplicate = 1;
+                               break;
+                       }
+               }
+
+               if (duplicate) {
+                       cgroup_dbg("controller %s is already mounted on %s\n",
+                               mntopt, cg_mount_table[j].mount.path);
+                       ret = cg_add_duplicate_mount(&cg_mount_table[j],
+                                       ent->mnt_dir);
+                       if (ret)
+                               goto out;
+                       /* continue with next controller */
+                       continue;
+               }
+
+               strncpy(cg_mount_table[*mnt_tbl_idx].name,
+                       controllers[i], FILENAME_MAX);
+               cg_mount_table[*mnt_tbl_idx].name[FILENAME_MAX-1] = '\0';
+               strncpy(cg_mount_table[*mnt_tbl_idx].mount.path,
+                       ent->mnt_dir, FILENAME_MAX);
+               cg_mount_table[*mnt_tbl_idx].mount.path[FILENAME_MAX-1] =
+                       '\0';
+               cg_mount_table[*mnt_tbl_idx].mount.next = NULL;
+               cgroup_dbg("Found cgroup option %s, count %d\n",
+                       ent->mnt_opts, *mnt_tbl_idx);
+               (*mnt_tbl_idx)++;
+       }
+
+       /*
+        * Doesn't match the controller.
+        * Check if it is a named hierarchy.
+        */
+       mntopt = hasmntopt(ent, "name");
+
+       if (mntopt) {
+               mntopt = strtok_r(mntopt, ",", &strtok_buffer);
+               if (!mntopt)
+                       goto out;
+               /*
+                * Check if it is a duplicate
+                */
+               duplicate = 0;
+
+#ifdef OPAQUE_HIERARCHY
+               /*
+                * Ignore the opaque hierarchy.
+                */
+               if (strcmp(mntopt, OPAQUE_HIERARCHY) == 0)
+                       goto out;
+#endif
+
+               for (j = 0; j < *mnt_tbl_idx; j++) {
+                       if (strncmp(mntopt, cg_mount_table[j].name,
+                                               FILENAME_MAX) == 0) {
+                               duplicate = 1;
+                               break;
+                       }
+               }
+
+               if (duplicate) {
+                       cgroup_dbg("controller %s is already mounted on %s\n",
+                               mntopt, cg_mount_table[j].mount.path);
+                       ret = cg_add_duplicate_mount(&cg_mount_table[j],
+                                       ent->mnt_dir);
+                       goto out;
+               }
+
+               strncpy(cg_mount_table[*mnt_tbl_idx].name,
+                       mntopt, FILENAME_MAX);
+               cg_mount_table[*mnt_tbl_idx].name[FILENAME_MAX-1] = '\0';
+               strncpy(cg_mount_table[*mnt_tbl_idx].mount.path,
+                       ent->mnt_dir, FILENAME_MAX);
+               cg_mount_table[*mnt_tbl_idx].mount.path[FILENAME_MAX-1] =
+                       '\0';
+               cg_mount_table[*mnt_tbl_idx].mount.next = NULL;
+               cgroup_dbg("Found cgroup option %s, count %d\n",
+                       ent->mnt_opts, *mnt_tbl_idx);
+               (*mnt_tbl_idx)++;
+       }
+
+out:
+       return ret;
+}
+
 /**
  * cgroup_init(), initializes the MOUNT_POINT.
  *
@@ -1053,13 +1167,9 @@ int cgroup_init(void)
        char subsys_name[FILENAME_MAX];
        int hierarchy, num_cgroups, enabled;
        int i = 0;
-       int j;
-       int duplicate = 0;
-       char *mntopt = NULL;
        int err;
        char *buf = NULL;
        char mntent_buffer[4 * FILENAME_MAX];
-       char *strtok_buffer = NULL;
 
        cgroup_set_default_logger(-1);
 
@@ -1139,103 +1249,11 @@ int cgroup_init(void)
        while ((ent = getmntent_r(proc_mount, temp_ent,
                                        mntent_buffer,
                                        sizeof(mntent_buffer))) != NULL) {
-               if (strcmp(ent->mnt_type, "cgroup"))
-                       continue;
-
-               for (i = 0; controllers[i] != NULL; i++) {
-                       mntopt = hasmntopt(ent, controllers[i]);
-
-                       if (!mntopt)
-                               continue;
-
-                       cgroup_dbg("found %s in %s\n", controllers[i], ent->mnt_opts);
-
-                       /* do not have duplicates in mount table */
-                       duplicate = 0;
-                       for  (j = 0; j < found_mnt; j++) {
-                               if (strncmp(controllers[i],
-                                                       cg_mount_table[j].name,
-                                                       FILENAME_MAX) == 0) {
-                                       duplicate = 1;
-                                       break;
-                               }
-                       }
-                       if (duplicate) {
-                               cgroup_dbg("controller %s is already mounted on %s\n",
-                                       mntopt, cg_mount_table[j].mount.path);
-                               ret = cg_add_duplicate_mount(&cg_mount_table[j],
-                                               ent->mnt_dir);
-                               if (ret)
-                                       goto unlock_exit;
-                               /* continue with next controller */
-                               continue;
-                       }
-
-                       strncpy(cg_mount_table[found_mnt].name,
-                               controllers[i], FILENAME_MAX);
-                       cg_mount_table[found_mnt].name[FILENAME_MAX-1] = '\0';
-                       strncpy(cg_mount_table[found_mnt].mount.path,
-                               ent->mnt_dir, FILENAME_MAX);
-                       cg_mount_table[found_mnt].mount.path[FILENAME_MAX-1] =
-                               '\0';
-                       cg_mount_table[found_mnt].mount.next = NULL;
-                       cgroup_dbg("Found cgroup option %s, count %d\n",
-                               ent->mnt_opts, found_mnt);
-                       found_mnt++;
-               }
-
-               /*
-                * Doesn't match the controller.
-                * Check if it is a named hierarchy.
-                */
-               mntopt = hasmntopt(ent, "name");
-
-               if (mntopt) {
-                       mntopt = strtok_r(mntopt, ",", &strtok_buffer);
-                       if (!mntopt)
-                               continue;
-                       /*
-                        * Check if it is a duplicate
-                        */
-                       duplicate = 0;
-
-#ifdef OPAQUE_HIERARCHY
-                       /*
-                        * Ignore the opaque hierarchy.
-                        */
-                       if (strcmp(mntopt, OPAQUE_HIERARCHY) == 0)
-                                       continue;
-#endif
-
-                       for (j = 0; j < found_mnt; j++) {
-                               if (strncmp(mntopt, cg_mount_table[j].name,
-                                                       FILENAME_MAX) == 0) {
-                                       duplicate = 1;
-                                       break;
-                               }
-                       }
-
-                       if (duplicate) {
-                               cgroup_dbg("controller %s is already mounted on %s\n",
-                                       mntopt, cg_mount_table[j].mount.path);
-                               ret = cg_add_duplicate_mount(&cg_mount_table[j],
-                                               ent->mnt_dir);
-                               if (ret)
-                                       goto unlock_exit;
-                               continue;
-                       }
-
-                       strncpy(cg_mount_table[found_mnt].name,
-                               mntopt, FILENAME_MAX);
-                       cg_mount_table[found_mnt].name[FILENAME_MAX-1] = '\0';
-                       strncpy(cg_mount_table[found_mnt].mount.path,
-                               ent->mnt_dir, FILENAME_MAX);
-                       cg_mount_table[found_mnt].mount.path[FILENAME_MAX-1] =
-                               '\0';
-                       cg_mount_table[found_mnt].mount.next = NULL;
-                       cgroup_dbg("Found cgroup option %s, count %d\n",
-                               ent->mnt_opts, found_mnt);
-                       found_mnt++;
+               if (strcmp(ent->mnt_type, "cgroup") == 0) {
+                       ret = cgroup_process_v1_mnt(controllers, ent,
+                                                   &found_mnt);
+                       if (ret)
+                               goto unlock_exit;
                }
        }