cgfsng: s/25/INTTYPE_TO_STRLEN(pid_t)/g

[mirror_lxc.git] / src / lxc / cgroups / cgfsng.c

diff --git a/src/lxc/cgroups/cgfsng.c b/src/lxc/cgroups/cgfsng.c
index 5475f7eff0f5502ed52b3d99597296ab94544697..7388ad7675525a4a2fc112f9499c42b5b9f4cf71 100644 (file)
--- a/src/lxc/cgroups/cgfsng.c
+++ b/src/lxc/cgroups/cgfsng.c
@@ -1111,7 +1111,8 @@ static int cgroup_rmdir_wrapper(void *data)
        return cgroup_rmdir(arg->hierarchies, arg->container_cgroup);
 }
 
-__cgfsng_ops static void cgfsng_destroy(struct cgroup_ops *ops, struct lxc_handler *handler)
+__cgfsng_ops static void cgfsng_payload_destroy(struct cgroup_ops *ops,
+                                               struct lxc_handler *handler)
 {
        int ret;
        struct generic_userns_exec_data wrap;
@@ -1132,6 +1133,60 @@ __cgfsng_ops static void cgfsng_destroy(struct cgroup_ops *ops, struct lxc_handl
        }
 }
 
+__cgfsng_ops static void cgfsng_monitor_destroy(struct cgroup_ops *ops,
+                                               struct lxc_handler *handler)
+{
+       int len;
+       char *pivot_path;
+       struct lxc_conf *conf = handler->conf;
+       char pidstr[INTTYPE_TO_STRLEN(pid_t)];
+
+       if (!ops->hierarchies)
+               return;
+
+       len = snprintf(pidstr, sizeof(pidstr), "%d", handler->monitor_pid);
+       if (len < 0 || (size_t)len >= sizeof(pidstr))
+               return;
+
+       for (int i = 0; ops->hierarchies[i]; i++) {
+               int ret;
+               struct hierarchy *h = ops->hierarchies[i];
+
+               if (!h->monitor_full_path)
+                       continue;
+
+               if (conf && conf->cgroup_meta.dir)
+                       pivot_path = must_make_path(h->mountpoint,
+                                                   h->container_base_path,
+                                                   conf->cgroup_meta.dir,
+                                                   PIVOT_CGROUP,
+                                                   "cgroup.procs", NULL);
+               else
+                       pivot_path = must_make_path(h->mountpoint,
+                                                   h->container_base_path,
+                                                   PIVOT_CGROUP,
+                                                   "cgroup.procs", NULL);
+
+               ret = mkdir_p(pivot_path, 0755);
+               if (ret < 0 && errno != EEXIST)
+                       goto next;
+
+               /* Move ourselves into the pivot cgroup to delete our own
+                * cgroup.
+                */
+               ret = lxc_write_to_file(pivot_path, pidstr, len, false, 0666);
+               if (ret != 0)
+                       goto next;
+
+               ret = recursive_destroy(h->monitor_full_path);
+               if (ret < 0)
+                       WARN("Failed to destroy \"%s\"", h->monitor_full_path);
+
+       next:
+               free(pivot_path);
+       }
+}
+
 static bool cg_unified_create_cgroup(struct hierarchy *h, char *cgname)
 {
        size_t i, parts_len;
@@ -1271,7 +1326,9 @@ static void remove_path_for_hierarchy(struct hierarchy *h, char *cgname, bool mo
 __cgfsng_ops static inline bool cgfsng_monitor_create(struct cgroup_ops *ops,
                                                        struct lxc_handler *handler)
 {
-       char *monitor_cgroup;
+       char *monitor_cgroup, *offset, *tmp;
+       int idx = 0;
+       size_t len;
        bool bret = false;
        struct lxc_conf *conf = handler->conf;
 
@@ -1279,24 +1336,46 @@ __cgfsng_ops static inline bool cgfsng_monitor_create(struct cgroup_ops *ops,
                return bret;
 
        if (conf->cgroup_meta.dir)
-               monitor_cgroup = lxc_string_join("/", (const char *[]){conf->cgroup_meta.dir, ops->monitor_pattern, handler->name, NULL}, false);
+               tmp = lxc_string_join("/",
+                                     (const char *[]){conf->cgroup_meta.dir,
+                                                      ops->monitor_pattern,
+                                                      handler->name, NULL},
+                                     false);
        else
-               monitor_cgroup = must_make_path(ops->monitor_pattern, handler->name, NULL);
-       if (!monitor_cgroup)
+               tmp = must_make_path(ops->monitor_pattern, handler->name, NULL);
+       if (!tmp)
                return bret;
 
-       for (int i = 0; ops->hierarchies[i]; i++) {
-               if (!monitor_create_path_for_hierarchy(ops->hierarchies[i], monitor_cgroup)) {
-                       ERROR("Failed to create cgroup \"%s\"", ops->hierarchies[i]->monitor_full_path);
-                       free(ops->hierarchies[i]->container_full_path);
-                       ops->hierarchies[i]->container_full_path = NULL;
-                       for (int j = 0; j < i; j++)
-                               remove_path_for_hierarchy(ops->hierarchies[j], monitor_cgroup, true);
-                       goto on_error;
+       len = strlen(tmp) + 5; /* leave room for -NNN\0 */
+       monitor_cgroup = must_alloc(len);
+       (void)strlcpy(monitor_cgroup, tmp, len);
+       free(tmp);
+       offset = monitor_cgroup + len - 5;
+
+       do {
+               if (idx) {
+                       int ret = snprintf(offset, 5, "-%d", idx);
+                       if (ret < 0 || (size_t)ret >= 5)
+                               goto on_error;
                }
-       }
 
-       bret = true;
+               for (int i = 0; ops->hierarchies[i]; i++) {
+                       if (!monitor_create_path_for_hierarchy(ops->hierarchies[i], monitor_cgroup)) {
+                               ERROR("Failed to create cgroup \"%s\"", ops->hierarchies[i]->monitor_full_path);
+                               free(ops->hierarchies[i]->container_full_path);
+                               ops->hierarchies[i]->container_full_path = NULL;
+
+                               for (int j = 0; j < i; j++)
+                                       remove_path_for_hierarchy(ops->hierarchies[j], monitor_cgroup, true);
+
+                               idx++;
+                               break;
+                       }
+               }
+       } while (idx > 0 && idx < 1000);
+
+       if (idx < 1000)
+               bret = true;
 
 on_error:
        free(monitor_cgroup);
@@ -1386,10 +1465,10 @@ __cgfsng_ops static bool __do_cgroup_enter(struct cgroup_ops *ops, pid_t pid,
                                             bool monitor)
 {
        int len;
-       char pidstr[25];
+       char pidstr[INTTYPE_TO_STRLEN(pid_t)];
 
-       len = snprintf(pidstr, 25, "%d", pid);
-       if (len < 0 || len >= 25)
+       len = snprintf(pidstr, sizeof(pidstr), "%d", pid);
+       if (len < 0 || (size_t)len >= sizeof(pidstr))
                return false;
 
        for (int i = 0; ops->hierarchies[i]; i++) {
@@ -2018,10 +2097,10 @@ __cgfsng_ops static bool cgfsng_attach(struct cgroup_ops *ops, const char *name,
                                         const char *lxcpath, pid_t pid)
 {
        int i, len, ret;
-       char pidstr[25];
+       char pidstr[INTTYPE_TO_STRLEN(pid_t)];
 
-       len = snprintf(pidstr, 25, "%d", pid);
-       if (len < 0 || len >= 25)
+       len = snprintf(pidstr, sizeof(pidstr), "%d", pid);
+       if (len < 0 || (size_t)len >= sizeof(pidstr))
                return false;
 
        for (i = 0; ops->hierarchies[i]; i++) {
@@ -2659,7 +2738,7 @@ __cgfsng_ops static bool cgfsng_data_init(struct cgroup_ops *ops)
                return false;
        }
        ops->cgroup_pattern = must_copy_string(cgroup_pattern);
-       ops->monitor_pattern = must_copy_string("lxc.monitor");
+       ops->monitor_pattern = MONITOR_CGROUP;
 
        return true;
 }
@@ -2681,7 +2760,8 @@ struct cgroup_ops *cgfsng_ops_init(struct lxc_conf *conf)
        }
 
        cgfsng_ops->data_init = cgfsng_data_init;
-       cgfsng_ops->destroy = cgfsng_destroy;
+       cgfsng_ops->payload_destroy = cgfsng_payload_destroy;
+       cgfsng_ops->monitor_destroy = cgfsng_monitor_destroy;
        cgfsng_ops->monitor_create = cgfsng_monitor_create;
        cgfsng_ops->monitor_enter = cgfsng_monitor_enter;
        cgfsng_ops->payload_create = cgfsng_payload_create;