From: Kamalesh Babulal <kamalesh.babulal@oracle.com>
Date: Fri, 8 Mar 2024 01:59:54 +0000 (+0530)
Subject: api: add new API cgroup_attach_thread_tid() (v1)
X-Git-Tag: v3.2.0~127
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=11d233dd59313c42d1414a28449345b0bf18477e;p=thirdparty%2Flibcgroup.git

api: add new API cgroup_attach_thread_tid() (v1)

Add a new API cgroup_attach_thread_tid(), that will allow the users to
move all threads sharing the same tid (thread group leader).

Example:
---------
 #include <libcgroup.h>
 #include <stdio.h>
 #include <stdlib.h>

 #define CGRP_NAME "cgrp_foo"

 int main(int argc, char **argv)
 {
         struct cgroup_controller *cgc = NULL;
         struct cgroup *cgroup = NULL;
         int ret = 0;

         ret = cgroup_init();
         if (ret) {
                 fprintf(stderr, "cgroup_init failed\n");
                 exit(1);
         }

         cgroup = cgroup_new_cgroup(CGRP_NAME);
         if (!cgroup) {
                 fprintf(stderr, "Failed to allocate cgroup %s\n", CGRP_NAME);
                 exit(1);
         }

         cgc = cgroup_add_controller(cgroup, "cpu");
         if (!cgc) {
                 fprintf(stderr, "Failed to add controller cpu cgroup %s\n", CGRP_NAME);
                 exit(1);
         }

         ret = cgroup_create_cgroup(cgroup, 0);
         if (ret)
                 fprintf(stderr, "Failed to create cgroup %s\n", CGRP_NAME);

         ret = cgroup_attach_thread_tid(cgroup, atoi(argv[1]));
         if (ret)
                 fprintf(stderr, "failed to write threads tid %d\n", atoi(argv[1]));

         cgroup_free(&cgroup);

         exit(0);
 }

Signed-off-by: Kamalesh Babulal <kamalesh.babulal@oracle.com>
Signed-off-by: Tom Hromatka <tom.hromatka@oracle.com>
---

diff --git a/include/libcgroup/tasks.h b/include/libcgroup/tasks.h
index 77a85265..b504bf52 100644
--- a/include/libcgroup/tasks.h
+++ b/include/libcgroup/tasks.h
@@ -203,6 +203,13 @@ int cgroup_change_cgroup_uid_gid(uid_t uid, gid_t gid, pid_t pid);
  */
 int cgroup_register_unchanged_process(pid_t pid, int flags);
 
+/**
+ * Move given threads (=thread) to given control group.
+ * @param cgroup Destination control group.
+ * @param tid The task to move.
+ */
+int cgroup_attach_thread_tid(struct cgroup *cgroup, pid_t tid);
+
 /**
  * @}
  * @}
diff --git a/src/api.c b/src/api.c
index 161cdb97..645e9a62 100644
--- a/src/api.c
+++ b/src/api.c
@@ -2139,6 +2139,20 @@ int cgroup_attach_task(struct cgroup *cgroup)
 	return cgroup_attach_task_tid(cgroup, tid, 0);
 }
 
+/**
+ *  cgroup_attach_thread_tid is used to assign threads to a cgroup.
+ *  struct cgroup *cgroup: The cgroup to assign the thread to.
+ *  pid_t tid: The thread to be assigned to the cgroup.
+ *
+ *  returns 0 on success.
+ *  returns ECGROUPNOTOWNER if the caller does not have access to the cgroup.
+ *  returns ECGROUPNOTALLOWED for other causes of failure.
+ */
+int cgroup_attach_thread_tid(struct cgroup *cgroup, pid_t tid)
+{
+	return cgroup_attach_task_tid(cgroup, tid, 1);
+}
+
 /**
  * cg_mkdir_p, emulate the mkdir -p command (recursively creating paths)
  * @path: path to create
diff --git a/src/libcgroup.map b/src/libcgroup.map
index 2e37d76e..31780656 100644
--- a/src/libcgroup.map
+++ b/src/libcgroup.map
@@ -162,4 +162,5 @@ CGROUP_3.0 {
 	is_cgroup_mode_hybrid;
 	is_cgroup_mode_unified;
 	cgroup_is_systemd_enabled;
+	cgroup_attach_thread_tid;
 } CGROUP_2.0;