+++ /dev/null
-/*-
- * GPL LICENSE SUMMARY
- *
- * Copyright(c) 2010-2014 Intel Corporation. All rights reserved.
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of version 2 of the GNU General Public License as
- * published by the Free Software Foundation.
- *
- * This program is distributed in the hope that it will be useful, but
- * WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
- * General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program; if not, write to the Free Software
- * Foundation, Inc., 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
- * The full GNU General Public License is included in this distribution
- * in the file called LICENSE.GPL.
- *
- * Contact Information:
- * Intel Corporation
- */
-
-#include <linux/miscdevice.h>
-#include <linux/module.h>
-#include <linux/file.h>
-#include <linux/fdtable.h>
-#include <linux/syscalls.h>
-
-#include "eventfd_link.h"
-
-
-/*
- * get_files_struct is copied from fs/file.c
- */
-struct files_struct *
-get_files_struct(struct task_struct *task)
-{
- struct files_struct *files;
-
- task_lock(task);
- files = task->files;
- if (files)
- atomic_inc(&files->count);
- task_unlock(task);
-
- return files;
-}
-
-/*
- * put_files_struct is extracted from fs/file.c
- */
-void
-put_files_struct(struct files_struct *files)
-{
- if (atomic_dec_and_test(&files->count))
- BUG();
-}
-
-static struct file *
-fget_from_files(struct files_struct *files, unsigned fd)
-{
- struct file *file;
-
- rcu_read_lock();
- file = fcheck_files(files, fd);
- if (file) {
- if (file->f_mode & FMODE_PATH ||
- !atomic_long_inc_not_zero(&file->f_count)) {
-
- file = NULL;
- }
- }
- rcu_read_unlock();
-
- return file;
-}
-
-static long
-eventfd_link_ioctl_copy2(unsigned long arg)
-{
- void __user *argp = (void __user *) arg;
- struct task_struct *task_target = NULL;
- struct file *file;
- struct files_struct *files;
- struct eventfd_copy2 eventfd_copy2;
- long ret = -EFAULT;
-
- if (copy_from_user(&eventfd_copy2, argp, sizeof(struct eventfd_copy2)))
- goto out;
-
- /*
- * Find the task struct for the target pid
- */
- ret = -ESRCH;
-
- task_target =
- get_pid_task(find_vpid(eventfd_copy2.pid), PIDTYPE_PID);
- if (task_target == NULL) {
- pr_info("Unable to find pid %d\n", eventfd_copy2.pid);
- goto out;
- }
-
- ret = -ESTALE;
- files = get_files_struct(task_target);
- if (files == NULL) {
- pr_info("Failed to get target files struct\n");
- goto out_task;
- }
-
- ret = -EBADF;
- file = fget_from_files(files, eventfd_copy2.fd);
- put_files_struct(files);
-
- if (file == NULL) {
- pr_info("Failed to get fd %d from target\n", eventfd_copy2.fd);
- goto out_task;
- }
-
- /*
- * Install the file struct from the target process into the
- * newly allocated file desciptor of the source process.
- */
- ret = get_unused_fd_flags(eventfd_copy2.flags);
- if (ret < 0) {
- fput(file);
- goto out_task;
- }
- fd_install(ret, file);
-
-out_task:
- put_task_struct(task_target);
-out:
- return ret;
-}
-
-static long
-eventfd_link_ioctl_copy(unsigned long arg)
-{
- void __user *argp = (void __user *) arg;
- struct task_struct *task_target = NULL;
- struct file *file;
- struct files_struct *files;
- struct fdtable *fdt;
- struct eventfd_copy eventfd_copy;
- long ret = -EFAULT;
-
- if (copy_from_user(&eventfd_copy, argp, sizeof(struct eventfd_copy)))
- goto out;
-
- /*
- * Find the task struct for the target pid
- */
- ret = -ESRCH;
-
- task_target =
- get_pid_task(find_vpid(eventfd_copy.target_pid), PIDTYPE_PID);
- if (task_target == NULL) {
- pr_info("Unable to find pid %d\n", eventfd_copy.target_pid);
- goto out;
- }
-
- ret = -ESTALE;
- files = get_files_struct(current);
- if (files == NULL) {
- pr_info("Failed to get current files struct\n");
- goto out_task;
- }
-
- ret = -EBADF;
- file = fget_from_files(files, eventfd_copy.source_fd);
-
- if (file == NULL) {
- pr_info("Failed to get fd %d from source\n",
- eventfd_copy.source_fd);
- put_files_struct(files);
- goto out_task;
- }
-
- /*
- * Release the existing eventfd in the source process
- */
- spin_lock(&files->file_lock);
- fput(file);
- filp_close(file, files);
- fdt = files_fdtable(files);
- fdt->fd[eventfd_copy.source_fd] = NULL;
- spin_unlock(&files->file_lock);
-
- put_files_struct(files);
-
- /*
- * Find the file struct associated with the target fd.
- */
-
- ret = -ESTALE;
- files = get_files_struct(task_target);
- if (files == NULL) {
- pr_info("Failed to get target files struct\n");
- goto out_task;
- }
-
- ret = -EBADF;
- file = fget_from_files(files, eventfd_copy.target_fd);
- put_files_struct(files);
-
- if (file == NULL) {
- pr_info("Failed to get fd %d from target\n",
- eventfd_copy.target_fd);
- goto out_task;
- }
-
- /*
- * Install the file struct from the target process into the
- * file desciptor of the source process,
- */
-
- fd_install(eventfd_copy.source_fd, file);
- ret = 0;
-
-out_task:
- put_task_struct(task_target);
-out:
- return ret;
-}
-
-static long
-eventfd_link_ioctl(struct file *f, unsigned int ioctl, unsigned long arg)
-{
- long ret = -ENOIOCTLCMD;
-
- switch (ioctl) {
- case EVENTFD_COPY:
- ret = eventfd_link_ioctl_copy(arg);
- break;
- case EVENTFD_COPY2:
- ret = eventfd_link_ioctl_copy2(arg);
- break;
- }
-
- return ret;
-}
-
-static const struct file_operations eventfd_link_fops = {
- .owner = THIS_MODULE,
- .unlocked_ioctl = eventfd_link_ioctl,
-};
-
-
-static struct miscdevice eventfd_link_misc = {
- .minor = MISC_DYNAMIC_MINOR,
- .name = "eventfd-link",
- .fops = &eventfd_link_fops,
-};
-
-static int __init
-eventfd_link_init(void)
-{
- return misc_register(&eventfd_link_misc);
-}
-
-module_init(eventfd_link_init);
-
-static void __exit
-eventfd_link_exit(void)
-{
- misc_deregister(&eventfd_link_misc);
-}
-
-module_exit(eventfd_link_exit);
-
-MODULE_VERSION("0.0.1");
-MODULE_LICENSE("GPL v2");
-MODULE_AUTHOR("Anthony Fee");
-MODULE_DESCRIPTION("Link eventfd");
-MODULE_ALIAS("devname:eventfd-link");
Code Review / deb_dpdk.git / blobdiff