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442 lines
10 KiB
442 lines
10 KiB
// SPDX-License-Identifier: GPL-2.0-or-later |
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/* |
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* An implementation of a loadable kernel mode driver providing |
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* multiple kernel/user space bidirectional communications links. |
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* |
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* Author: Alan Cox <[email protected]> |
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* |
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* Adapted to become the Linux 2.0 Coda pseudo device |
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* Peter Braam <[email protected]> |
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* Michael Callahan <[email protected]> |
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* |
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* Changes for Linux 2.1 |
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* Copyright (c) 1997 Carnegie-Mellon University |
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*/ |
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#include <linux/module.h> |
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#include <linux/errno.h> |
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#include <linux/kernel.h> |
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#include <linux/major.h> |
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#include <linux/time.h> |
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#include <linux/sched/signal.h> |
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#include <linux/slab.h> |
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#include <linux/ioport.h> |
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#include <linux/fcntl.h> |
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#include <linux/delay.h> |
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#include <linux/skbuff.h> |
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#include <linux/proc_fs.h> |
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#include <linux/vmalloc.h> |
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#include <linux/fs.h> |
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#include <linux/file.h> |
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#include <linux/poll.h> |
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#include <linux/init.h> |
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#include <linux/list.h> |
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#include <linux/mutex.h> |
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#include <linux/device.h> |
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#include <linux/pid_namespace.h> |
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#include <asm/io.h> |
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#include <linux/uaccess.h> |
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#include <linux/coda.h> |
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#include "coda_psdev.h" |
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#include "coda_linux.h" |
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#include "coda_int.h" |
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|
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/* statistics */ |
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int coda_hard; /* allows signals during upcalls */ |
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unsigned long coda_timeout = 30; /* .. secs, then signals will dequeue */ |
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struct venus_comm coda_comms[MAX_CODADEVS]; |
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static struct class *coda_psdev_class; |
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/* |
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* Device operations |
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*/ |
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static __poll_t coda_psdev_poll(struct file *file, poll_table * wait) |
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{ |
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struct venus_comm *vcp = (struct venus_comm *) file->private_data; |
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__poll_t mask = EPOLLOUT | EPOLLWRNORM; |
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poll_wait(file, &vcp->vc_waitq, wait); |
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mutex_lock(&vcp->vc_mutex); |
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if (!list_empty(&vcp->vc_pending)) |
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mask |= EPOLLIN | EPOLLRDNORM; |
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mutex_unlock(&vcp->vc_mutex); |
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return mask; |
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} |
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static long coda_psdev_ioctl(struct file * filp, unsigned int cmd, unsigned long arg) |
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{ |
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unsigned int data; |
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switch(cmd) { |
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case CIOC_KERNEL_VERSION: |
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data = CODA_KERNEL_VERSION; |
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return put_user(data, (int __user *) arg); |
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default: |
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return -ENOTTY; |
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} |
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return 0; |
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} |
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/* |
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* Receive a message written by Venus to the psdev |
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*/ |
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static ssize_t coda_psdev_write(struct file *file, const char __user *buf, |
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size_t nbytes, loff_t *off) |
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{ |
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struct venus_comm *vcp = (struct venus_comm *) file->private_data; |
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struct upc_req *req = NULL; |
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struct upc_req *tmp; |
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struct list_head *lh; |
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struct coda_in_hdr hdr; |
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ssize_t retval = 0, count = 0; |
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int error; |
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/* make sure there is enough to copy out the (opcode, unique) values */ |
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if (nbytes < (2 * sizeof(u_int32_t))) |
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return -EINVAL; |
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/* Peek at the opcode, uniquefier */ |
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if (copy_from_user(&hdr, buf, 2 * sizeof(u_int32_t))) |
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return -EFAULT; |
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if (DOWNCALL(hdr.opcode)) { |
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union outputArgs *dcbuf; |
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int size = sizeof(*dcbuf); |
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if ( nbytes < sizeof(struct coda_out_hdr) ) { |
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pr_warn("coda_downcall opc %d uniq %d, not enough!\n", |
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hdr.opcode, hdr.unique); |
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count = nbytes; |
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goto out; |
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} |
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if ( nbytes > size ) { |
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pr_warn("downcall opc %d, uniq %d, too much!", |
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hdr.opcode, hdr.unique); |
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nbytes = size; |
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} |
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dcbuf = kvmalloc(nbytes, GFP_KERNEL); |
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if (!dcbuf) { |
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retval = -ENOMEM; |
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goto out; |
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} |
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if (copy_from_user(dcbuf, buf, nbytes)) { |
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kvfree(dcbuf); |
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retval = -EFAULT; |
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goto out; |
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} |
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/* what downcall errors does Venus handle ? */ |
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error = coda_downcall(vcp, hdr.opcode, dcbuf, nbytes); |
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kvfree(dcbuf); |
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if (error) { |
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pr_warn("%s: coda_downcall error: %d\n", |
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__func__, error); |
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retval = error; |
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goto out; |
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} |
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count = nbytes; |
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goto out; |
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} |
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/* Look for the message on the processing queue. */ |
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mutex_lock(&vcp->vc_mutex); |
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list_for_each(lh, &vcp->vc_processing) { |
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tmp = list_entry(lh, struct upc_req , uc_chain); |
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if (tmp->uc_unique == hdr.unique) { |
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req = tmp; |
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list_del(&req->uc_chain); |
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break; |
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} |
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} |
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mutex_unlock(&vcp->vc_mutex); |
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if (!req) { |
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pr_warn("%s: msg (%d, %d) not found\n", |
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__func__, hdr.opcode, hdr.unique); |
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retval = -ESRCH; |
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goto out; |
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} |
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/* move data into response buffer. */ |
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if (req->uc_outSize < nbytes) { |
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pr_warn("%s: too much cnt: %d, cnt: %ld, opc: %d, uniq: %d.\n", |
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__func__, req->uc_outSize, (long)nbytes, |
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hdr.opcode, hdr.unique); |
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nbytes = req->uc_outSize; /* don't have more space! */ |
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} |
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if (copy_from_user(req->uc_data, buf, nbytes)) { |
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req->uc_flags |= CODA_REQ_ABORT; |
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wake_up(&req->uc_sleep); |
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retval = -EFAULT; |
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goto out; |
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} |
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/* adjust outsize. is this useful ?? */ |
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req->uc_outSize = nbytes; |
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req->uc_flags |= CODA_REQ_WRITE; |
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count = nbytes; |
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/* Convert filedescriptor into a file handle */ |
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if (req->uc_opcode == CODA_OPEN_BY_FD) { |
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struct coda_open_by_fd_out *outp = |
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(struct coda_open_by_fd_out *)req->uc_data; |
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if (!outp->oh.result) { |
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outp->fh = fget(outp->fd); |
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if (!outp->fh) |
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return -EBADF; |
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} |
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} |
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wake_up(&req->uc_sleep); |
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out: |
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return(count ? count : retval); |
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} |
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/* |
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* Read a message from the kernel to Venus |
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*/ |
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static ssize_t coda_psdev_read(struct file * file, char __user * buf, |
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size_t nbytes, loff_t *off) |
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{ |
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DECLARE_WAITQUEUE(wait, current); |
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struct venus_comm *vcp = (struct venus_comm *) file->private_data; |
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struct upc_req *req; |
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ssize_t retval = 0, count = 0; |
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if (nbytes == 0) |
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return 0; |
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mutex_lock(&vcp->vc_mutex); |
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add_wait_queue(&vcp->vc_waitq, &wait); |
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set_current_state(TASK_INTERRUPTIBLE); |
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while (list_empty(&vcp->vc_pending)) { |
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if (file->f_flags & O_NONBLOCK) { |
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retval = -EAGAIN; |
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break; |
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} |
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if (signal_pending(current)) { |
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retval = -ERESTARTSYS; |
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break; |
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} |
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mutex_unlock(&vcp->vc_mutex); |
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schedule(); |
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mutex_lock(&vcp->vc_mutex); |
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} |
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set_current_state(TASK_RUNNING); |
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remove_wait_queue(&vcp->vc_waitq, &wait); |
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if (retval) |
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goto out; |
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req = list_entry(vcp->vc_pending.next, struct upc_req,uc_chain); |
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list_del(&req->uc_chain); |
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/* Move the input args into userspace */ |
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count = req->uc_inSize; |
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if (nbytes < req->uc_inSize) { |
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pr_warn("%s: Venus read %ld bytes of %d in message\n", |
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__func__, (long)nbytes, req->uc_inSize); |
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count = nbytes; |
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} |
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if (copy_to_user(buf, req->uc_data, count)) |
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retval = -EFAULT; |
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/* If request was not a signal, enqueue and don't free */ |
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if (!(req->uc_flags & CODA_REQ_ASYNC)) { |
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req->uc_flags |= CODA_REQ_READ; |
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list_add_tail(&(req->uc_chain), &vcp->vc_processing); |
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goto out; |
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} |
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kvfree(req->uc_data); |
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kfree(req); |
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out: |
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mutex_unlock(&vcp->vc_mutex); |
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return (count ? count : retval); |
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} |
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static int coda_psdev_open(struct inode * inode, struct file * file) |
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{ |
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struct venus_comm *vcp; |
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int idx, err; |
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if (task_active_pid_ns(current) != &init_pid_ns) |
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return -EINVAL; |
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if (current_user_ns() != &init_user_ns) |
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return -EINVAL; |
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idx = iminor(inode); |
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if (idx < 0 || idx >= MAX_CODADEVS) |
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return -ENODEV; |
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err = -EBUSY; |
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vcp = &coda_comms[idx]; |
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mutex_lock(&vcp->vc_mutex); |
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if (!vcp->vc_inuse) { |
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vcp->vc_inuse++; |
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INIT_LIST_HEAD(&vcp->vc_pending); |
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INIT_LIST_HEAD(&vcp->vc_processing); |
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init_waitqueue_head(&vcp->vc_waitq); |
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vcp->vc_sb = NULL; |
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vcp->vc_seq = 0; |
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file->private_data = vcp; |
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err = 0; |
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} |
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mutex_unlock(&vcp->vc_mutex); |
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return err; |
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} |
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static int coda_psdev_release(struct inode * inode, struct file * file) |
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{ |
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struct venus_comm *vcp = (struct venus_comm *) file->private_data; |
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struct upc_req *req, *tmp; |
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if (!vcp || !vcp->vc_inuse ) { |
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pr_warn("%s: Not open.\n", __func__); |
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return -1; |
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} |
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mutex_lock(&vcp->vc_mutex); |
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/* Wakeup clients so they can return. */ |
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list_for_each_entry_safe(req, tmp, &vcp->vc_pending, uc_chain) { |
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list_del(&req->uc_chain); |
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/* Async requests need to be freed here */ |
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if (req->uc_flags & CODA_REQ_ASYNC) { |
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kvfree(req->uc_data); |
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kfree(req); |
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continue; |
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} |
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req->uc_flags |= CODA_REQ_ABORT; |
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wake_up(&req->uc_sleep); |
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} |
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list_for_each_entry_safe(req, tmp, &vcp->vc_processing, uc_chain) { |
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list_del(&req->uc_chain); |
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req->uc_flags |= CODA_REQ_ABORT; |
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wake_up(&req->uc_sleep); |
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} |
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file->private_data = NULL; |
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vcp->vc_inuse--; |
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mutex_unlock(&vcp->vc_mutex); |
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return 0; |
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} |
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static const struct file_operations coda_psdev_fops = { |
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.owner = THIS_MODULE, |
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.read = coda_psdev_read, |
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.write = coda_psdev_write, |
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.poll = coda_psdev_poll, |
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.unlocked_ioctl = coda_psdev_ioctl, |
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.open = coda_psdev_open, |
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.release = coda_psdev_release, |
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.llseek = noop_llseek, |
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}; |
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static int __init init_coda_psdev(void) |
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{ |
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int i, err = 0; |
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if (register_chrdev(CODA_PSDEV_MAJOR, "coda", &coda_psdev_fops)) { |
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pr_err("%s: unable to get major %d\n", |
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__func__, CODA_PSDEV_MAJOR); |
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return -EIO; |
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} |
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coda_psdev_class = class_create(THIS_MODULE, "coda"); |
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if (IS_ERR(coda_psdev_class)) { |
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err = PTR_ERR(coda_psdev_class); |
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goto out_chrdev; |
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} |
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for (i = 0; i < MAX_CODADEVS; i++) { |
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mutex_init(&(&coda_comms[i])->vc_mutex); |
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device_create(coda_psdev_class, NULL, |
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MKDEV(CODA_PSDEV_MAJOR, i), NULL, "cfs%d", i); |
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} |
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coda_sysctl_init(); |
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goto out; |
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out_chrdev: |
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unregister_chrdev(CODA_PSDEV_MAJOR, "coda"); |
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out: |
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return err; |
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} |
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MODULE_AUTHOR("Jan Harkes, Peter J. Braam"); |
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MODULE_DESCRIPTION("Coda Distributed File System VFS interface"); |
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MODULE_ALIAS_CHARDEV_MAJOR(CODA_PSDEV_MAJOR); |
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MODULE_LICENSE("GPL"); |
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MODULE_VERSION("7.0"); |
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static int __init init_coda(void) |
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{ |
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int status; |
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int i; |
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status = coda_init_inodecache(); |
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if (status) |
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goto out2; |
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status = init_coda_psdev(); |
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if ( status ) { |
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pr_warn("Problem (%d) in init_coda_psdev\n", status); |
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goto out1; |
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} |
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status = register_filesystem(&coda_fs_type); |
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if (status) { |
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pr_warn("failed to register filesystem!\n"); |
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goto out; |
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} |
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return 0; |
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out: |
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for (i = 0; i < MAX_CODADEVS; i++) |
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device_destroy(coda_psdev_class, MKDEV(CODA_PSDEV_MAJOR, i)); |
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class_destroy(coda_psdev_class); |
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unregister_chrdev(CODA_PSDEV_MAJOR, "coda"); |
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coda_sysctl_clean(); |
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out1: |
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coda_destroy_inodecache(); |
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out2: |
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return status; |
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} |
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static void __exit exit_coda(void) |
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{ |
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int err, i; |
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err = unregister_filesystem(&coda_fs_type); |
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if (err != 0) |
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pr_warn("failed to unregister filesystem\n"); |
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for (i = 0; i < MAX_CODADEVS; i++) |
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device_destroy(coda_psdev_class, MKDEV(CODA_PSDEV_MAJOR, i)); |
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class_destroy(coda_psdev_class); |
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unregister_chrdev(CODA_PSDEV_MAJOR, "coda"); |
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coda_sysctl_clean(); |
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coda_destroy_inodecache(); |
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} |
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module_init(init_coda); |
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module_exit(exit_coda); |
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