函数源码

Linux Kernel

v5.5.9

Brick Technologies Co., Ltd

Source File:kernel\cgroup\cgroup-v1.c Create Date:2022-07-27 12:15:05
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static ssize_t __cgroup1_procs_write(struct kernfs_open_file *of,
                     char *buf, size_t nbytes, loff_t off,
                     bool threadgroup)
{
    struct cgroup *cgrp;
    struct task_struct *task;
    const struct cred *cred, *tcred;
    ssize_t ret;
    bool locked;
 
    cgrp = cgroup_kn_lock_live(of->kn, false);
    if (!cgrp)
        return -ENODEV;
 
    task = cgroup_procs_write_start(buf, threadgroup, &locked);
    ret = PTR_ERR_OR_ZERO(task);
    if (ret)
        goto out_unlock;
 
    /*
     * Even if we're attaching all tasks in the thread group, we only
     * need to check permissions on one of them.
     */
    cred = current_cred();
    tcred = get_task_cred(task);
    if (!uid_eq(cred->euid, GLOBAL_ROOT_UID) &&
        !uid_eq(cred->euid, tcred->uid) &&
        !uid_eq(cred->euid, tcred->suid))
        ret = -EACCES;
    put_cred(tcred);
    if (ret)
        goto out_finish;
 
    ret = cgroup_attach_task(cgrp, task, threadgroup);
 
out_finish:
    cgroup_procs_write_finish(task, locked);
out_unlock:
    cgroup_kn_unlock(of->kn);
 
    return ret ?: nbytes;
}