cgroups: simplify string list handling

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

diff --git a/src/lxc/cgroups/cgfsng.c b/src/lxc/cgroups/cgfsng.c
index a1e2ff95e1f9dd9502c3e239e6e7d17dc36bbdb5..48de2731cb887f639270b4503d0ef2a75f9cd20b 100644 (file)
--- a/src/lxc/cgroups/cgfsng.c
+++ b/src/lxc/cgroups/cgfsng.c
@@ -305,34 +305,50 @@ __lxc_unused static bool all_controllers_found(struct cgroup_ops *ops)
        return true;
 }
 
-static char **__controller_list_empty(void)
+static char **list_new(void)
 {
-       __do_free_string_list char **aret = NULL;
-       int newentry;
+       __do_free_string_list char **list = NULL;
+       int idx;
+
+       idx = list_add((void ***)&list);
+       if (idx < 0)
+               return NULL;
 
-       newentry = list_add((void ***)&aret);
-       aret[newentry] = NULL;
-       return move_ptr(aret);
+       list[idx] = NULL;
+       return move_ptr(list);
 }
 
-static char **__controller_list(char *controllers)
+static int list_add_string(char ***list, char *entry)
 {
-       __do_free_string_list char **controller_list = NULL;
+       __do_free char *dup = NULL;
+       int idx;
+
+       dup = strdup(entry);
+       if (!dup)
+               return ret_errno(ENOMEM);
+
+       idx = list_add((void ***)list);
+       if (idx < 0)
+               return idx;
+
+       (*list)[idx] = move_ptr(dup);
+       return 0;
+}
+
+static char **list_add_controllers(char *controllers)
+{
+       __do_free_string_list char **list = NULL;
        char *it;
 
        lxc_iterate_parts(it, controllers, " \t\n") {
-               int idx;
+               int ret;
 
-               idx = list_add((void ***)&controller_list);
-               controller_list[idx] = strdup(it);
-               if (!controller_list[idx])
+               ret = list_add_string(&list, it);
+               if (ret < 0)
                        return NULL;
        }
 
-       if (!controller_list)
-               return NULL;
-
-       return move_ptr(controller_list);
+       return move_ptr(list);
 }
 
 static char **unified_controllers(int dfd, const char *file)
@@ -343,7 +359,7 @@ static char **unified_controllers(int dfd, const char *file)
        if (!buf)
                return NULL;
 
-       return __controller_list(buf);
+       return list_add_controllers(buf);
 }
 
 static bool skip_hierarchy(const struct cgroup_ops *ops, char **controllers)
@@ -403,20 +419,14 @@ static int add_hierarchy(struct cgroup_ops *ops, int dfd_mnt, char *mnt,
                TRACE("The hierarchy contains the %s controller", *it);
 
        idx = list_add((void ***)&ops->hierarchies);
+       if (idx < 0)
+               return ret_errno(idx);
+
        if (type == CGROUP2_SUPER_MAGIC)
                ops->unified = new;
        (ops->hierarchies)[idx] = move_ptr(new);
-       return 0;
-}
 
-static void must_append_string(char ***list, char *entry)
-{
-       int newentry;
-       char *copy;
-
-       newentry = list_add((void ***)list);
-       copy = must_copy_string(entry);
-       (*list)[newentry] = copy;
+       return 0;
 }
 
 static int cgroup_tree_remove(struct hierarchy **hierarchies, const char *path_prune)
@@ -2354,7 +2364,10 @@ __cgfsng_ops static int cgfsng_get(struct cgroup_ops *ops, const char *filename,
        if (!ops)
                return ret_set_errno(-1, ENOENT);
 
-       controller = must_copy_string(filename);
+       controller = strdup(filename);
+       if (!controller)
+               return ret_errno(ENOMEM);
+
        p = strchr(controller, '.');
        if (p)
                *p = '\0';
@@ -2498,7 +2511,10 @@ __cgfsng_ops static int cgfsng_set(struct cgroup_ops *ops,
            is_empty_string(name) || is_empty_string(lxcpath))
                return ret_errno(EINVAL);
 
-       controller = must_copy_string(key);
+       controller = strdup(key);
+       if (!controller)
+               return ret_errno(ENOMEM);
+
        p = strchr(controller, '.');
        if (p)
                *p = '\0';
@@ -2550,7 +2566,9 @@ static int device_cgroup_rule_parse_devpath(struct device_item *device,
        char *p;
        struct stat sb;
 
-       path = must_copy_string(devpath);
+       path = strdup(devpath);
+       if (!path)
+               return ret_errno(ENOMEM);
 
        /*
         * Read path followed by mode. Ignore any trailing text.
@@ -2637,7 +2655,10 @@ static int cg_legacy_set_data(struct cgroup_ops *ops, const char *filename,
        char converted_value[50];
        struct hierarchy *h;
 
-       controller = must_copy_string(filename);
+       controller = strdup(filename);
+       if (!controller)
+               return ret_errno(ENOMEM);
+
        p = strchr(controller, '.');
        if (p)
                *p = '\0';
@@ -2921,8 +2942,9 @@ __cgfsng_ops static bool cgfsng_payload_delegate_controllers(struct cgroup_ops *
        return __cgfsng_delegate_controllers(ops, ops->container_cgroup);
 }
 
-static int cg_unified_delegate(char ***delegate)
+static int list_unified_delegation_files(char ***delegate)
 {
+       __do_free char **list = NULL;
        __do_free char *buf = NULL;
        char *standard[] = {
                "cgroup.procs",
@@ -2932,15 +2954,17 @@ static int cg_unified_delegate(char ***delegate)
                NULL,
        };
        char *token;
-       int idx;
+       int ret;
 
        buf = read_file_at(-EBADF, "/sys/kernel/cgroup/delegate", PROTECT_OPEN, 0);
        if (!buf) {
                for (char **p = standard; p && *p; p++) {
-                       idx = list_add((void ***)delegate);
-                       (*delegate)[idx] = must_copy_string(*p);
+                       ret = list_add_string(&list, *p);
+                       if (ret < 0)
+                               return ret;
                }
 
+               *delegate = move_ptr(list);
                return syswarn(0, "Failed to read /sys/kernel/cgroup/delegate");
        }
 
@@ -2952,10 +2976,12 @@ static int cg_unified_delegate(char ***delegate)
                if (strequal(token, "cgroup.procs"))
                        continue;
 
-               idx = list_add((void ***)delegate);
-               (*delegate)[idx] = must_copy_string(token);
+               ret = list_add_string(&list, token);
+               if (ret < 0)
+                       return ret;
        }
 
+       *delegate = move_ptr(list);
        return 0;
 }
 
@@ -3059,11 +3085,13 @@ static int __initialize_cgroups(struct cgroup_ops *ops, bool relative,
                        controller_list = unified_controllers(dfd, "cgroup.controllers");
                        if (!controller_list) {
                                TRACE("No controllers are enabled for delegation in the unified hierarchy");
-                               controller_list = __controller_list_empty();
+                               controller_list = list_new();
+                               if (!controller_list)
+                                       return syserrno(-ENOMEM, "Failed to create empty controller list");
                        }
 
                        if (unprivileged) {
-                               ret = cg_unified_delegate(&delegate);
+                               ret = list_unified_delegation_files(&delegate);
                                if (ret < 0)
                                        return syserrno(ret, "Failed to determine delegation requirements");
 
@@ -3150,9 +3178,9 @@ static int __initialize_cgroups(struct cgroup_ops *ops, bool relative,
                         * controllers because we would otherwise chop the
                         * mountpoint.
                         */
-                       controller_list = __controller_list(__controllers);
-                       if (IS_ERR(controller_list))
-                               return PTR_ERR(controller_list);
+                       controller_list = list_add_controllers(__controllers);
+                       if (!controller_list)
+                               return syserrno(-ENOMEM, "Failed to create controller list from %s", __controllers);
 
                        if (skip_hierarchy(ops, controller_list))
                                continue;
@@ -3217,8 +3245,11 @@ static int initialize_cgroups(struct cgroup_ops *ops, struct lxc_conf *conf)
                if (!dup)
                        return -errno;
 
-               lxc_iterate_parts(it, dup, ",")
-                       must_append_string(&ops->cgroup_use, it);
+               lxc_iterate_parts(it, dup, ",") {
+                       ret = list_add_string(&ops->cgroup_use, it);
+                       if (ret < 0)
+                               return ret;
+               }
        }
 
        /*
@@ -3246,8 +3277,11 @@ __cgfsng_ops static int cgfsng_data_init(struct cgroup_ops *ops)
 
        /* copy system-wide cgroup information */
        cgroup_pattern = lxc_global_config_value("lxc.cgroup.pattern");
-       if (cgroup_pattern && !strequal(cgroup_pattern, ""))
-               ops->cgroup_pattern = must_copy_string(cgroup_pattern);
+       if (cgroup_pattern && !strequal(cgroup_pattern, "")) {
+               ops->cgroup_pattern = strdup(cgroup_pattern);
+               if (!ops->cgroup_pattern)
+                       return ret_errno(ENOMEM);
+       }
 
        return 0;
 }