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fs/coda/psdev.c
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// SPDX-License-Identifier: GPL-2.0-or-later |
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/* * An implementation of a loadable kernel mode driver providing * multiple kernel/user space bidirectional communications links. * |
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* Author: Alan Cox <alan@lxorguk.ukuu.org.uk> |
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* * Adapted to become the Linux 2.0 Coda pseudo device * Peter Braam <braam@maths.ox.ac.uk> * Michael Callahan <mjc@emmy.smith.edu> * * Changes for Linux 2.1 * Copyright (c) 1997 Carnegie-Mellon University */ #include <linux/module.h> #include <linux/errno.h> #include <linux/kernel.h> #include <linux/major.h> #include <linux/time.h> |
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#include <linux/sched/signal.h> |
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#include <linux/slab.h> #include <linux/ioport.h> #include <linux/fcntl.h> #include <linux/delay.h> #include <linux/skbuff.h> #include <linux/proc_fs.h> |
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#include <linux/vmalloc.h> #include <linux/fs.h> #include <linux/file.h> #include <linux/poll.h> #include <linux/init.h> #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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/* statistics */ int coda_hard; /* allows signals during upcalls */ unsigned long coda_timeout = 30; /* .. secs, then signals will dequeue */ struct venus_comm coda_comms[MAX_CODADEVS]; |
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static struct class *coda_psdev_class; |
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/* * Device operations */ |
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static __poll_t coda_psdev_poll(struct file *file, poll_table * wait) |
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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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static long coda_psdev_ioctl(struct file * filp, unsigned int cmd, unsigned long arg) |
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{ unsigned int data; switch(cmd) { case CIOC_KERNEL_VERSION: data = CODA_KERNEL_VERSION; return put_user(data, (int __user *) arg); default: return -ENOTTY; } return 0; } /* * Receive a message written by Venus to the psdev */ static ssize_t coda_psdev_write(struct file *file, const char __user *buf, size_t nbytes, loff_t *off) { struct venus_comm *vcp = (struct venus_comm *) file->private_data; struct upc_req *req = NULL; struct upc_req *tmp; struct list_head *lh; struct coda_in_hdr hdr; ssize_t retval = 0, count = 0; int error; |
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/* make sure there is enough to copy out the (opcode, unique) values */ if (nbytes < (2 * sizeof(u_int32_t))) 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; 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! ", hdr.opcode, hdr.unique); |
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count = nbytes; goto out; } 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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dcbuf = kvmalloc(nbytes, GFP_KERNEL); if (!dcbuf) { retval = -ENOMEM; goto out; } |
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if (copy_from_user(dcbuf, buf, nbytes)) { |
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kvfree(dcbuf); |
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retval = -EFAULT; goto out; } /* 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 ", __func__, error); |
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retval = error; goto out; } count = nbytes; goto out; } /* 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) { tmp = list_entry(lh, struct upc_req , uc_chain); if (tmp->uc_unique == hdr.unique) { req = tmp; list_del(&req->uc_chain); break; } } |
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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 ", __func__, hdr.opcode, hdr.unique); |
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retval = -ESRCH; goto out; } /* move data into response buffer. */ if (req->uc_outSize < nbytes) { |
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pr_warn("%s: too much cnt: %d, cnt: %ld, opc: %d, uniq: %d. ", __func__, req->uc_outSize, (long)nbytes, hdr.opcode, hdr.unique); |
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nbytes = req->uc_outSize; /* don't have more space! */ } 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); retval = -EFAULT; goto out; } /* adjust outsize. is this useful ?? */ |
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req->uc_outSize = nbytes; req->uc_flags |= CODA_REQ_WRITE; |
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count = nbytes; /* Convert filedescriptor into a file handle */ if (req->uc_opcode == CODA_OPEN_BY_FD) { struct coda_open_by_fd_out *outp = (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) return -EBADF; } |
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} wake_up(&req->uc_sleep); out: return(count ? count : retval); } /* * Read a message from the kernel to Venus */ static ssize_t coda_psdev_read(struct file * file, char __user * buf, size_t nbytes, loff_t *off) { DECLARE_WAITQUEUE(wait, current); struct venus_comm *vcp = (struct venus_comm *) file->private_data; struct upc_req *req; ssize_t retval = 0, count = 0; if (nbytes == 0) return 0; |
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mutex_lock(&vcp->vc_mutex); |
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add_wait_queue(&vcp->vc_waitq, &wait); set_current_state(TASK_INTERRUPTIBLE); while (list_empty(&vcp->vc_pending)) { if (file->f_flags & O_NONBLOCK) { retval = -EAGAIN; break; } if (signal_pending(current)) { retval = -ERESTARTSYS; break; } |
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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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} set_current_state(TASK_RUNNING); remove_wait_queue(&vcp->vc_waitq, &wait); if (retval) goto out; req = list_entry(vcp->vc_pending.next, struct upc_req,uc_chain); list_del(&req->uc_chain); /* Move the input args into userspace */ count = req->uc_inSize; if (nbytes < req->uc_inSize) { |
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pr_warn("%s: Venus read %ld bytes of %d in message ", __func__, (long)nbytes, req->uc_inSize); |
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count = nbytes; } if (copy_to_user(buf, req->uc_data, count)) retval = -EFAULT; /* If request was not a signal, enqueue and don't free */ |
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if (!(req->uc_flags & CODA_REQ_ASYNC)) { 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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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); } static int coda_psdev_open(struct inode * inode, struct file * file) { |
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struct venus_comm *vcp; int idx, err; |
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if (task_active_pid_ns(current) != &init_pid_ns) return -EINVAL; |
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if (current_user_ns() != &init_user_ns) 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) { vcp->vc_inuse++; |
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INIT_LIST_HEAD(&vcp->vc_pending); INIT_LIST_HEAD(&vcp->vc_processing); init_waitqueue_head(&vcp->vc_waitq); vcp->vc_sb = NULL; vcp->vc_seq = 0; |
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file->private_data = vcp; 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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} static int coda_psdev_release(struct inode * inode, struct file * file) { |
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struct venus_comm *vcp = (struct venus_comm *) file->private_data; struct upc_req *req, *tmp; |
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if (!vcp || !vcp->vc_inuse ) { |
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pr_warn("%s: Not open. ", __func__); |
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return -1; } |
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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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req->uc_flags |= CODA_REQ_ABORT; |
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wake_up(&req->uc_sleep); |
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} list_for_each_entry_safe(req, tmp, &vcp->vc_processing, uc_chain) { 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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file->private_data = NULL; vcp->vc_inuse--; |
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mutex_unlock(&vcp->vc_mutex); |
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return 0; } |
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static const struct file_operations coda_psdev_fops = { |
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.owner = THIS_MODULE, .read = coda_psdev_read, .write = coda_psdev_write, .poll = coda_psdev_poll, |
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.unlocked_ioctl = coda_psdev_ioctl, |
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.open = coda_psdev_open, .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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{ int i, err = 0; if (register_chrdev(CODA_PSDEV_MAJOR, "coda", &coda_psdev_fops)) { |
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pr_err("%s: unable to get major %d ", __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)) { err = PTR_ERR(coda_psdev_class); goto out_chrdev; } |
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for (i = 0; i < MAX_CODADEVS; i++) { mutex_init(&(&coda_comms[i])->vc_mutex); |
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device_create(coda_psdev_class, NULL, MKDEV(CODA_PSDEV_MAJOR, i), NULL, "cfs%d", i); |
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} |
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coda_sysctl_init(); goto out; |
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out_chrdev: unregister_chrdev(CODA_PSDEV_MAJOR, "coda"); out: return err; } |
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MODULE_AUTHOR("Jan Harkes, Peter J. Braam"); MODULE_DESCRIPTION("Coda Distributed File System VFS interface"); 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) { int status; int i; |
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status = coda_init_inodecache(); if (status) goto out2; status = init_coda_psdev(); if ( status ) { |
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pr_warn("Problem (%d) in init_coda_psdev ", status); |
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goto out1; } status = register_filesystem(&coda_fs_type); if (status) { |
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pr_warn("failed to register filesystem! "); |
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goto out; } return 0; 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"); coda_sysctl_clean(); out1: coda_destroy_inodecache(); out2: return status; } static void __exit exit_coda(void) { int err, i; err = unregister_filesystem(&coda_fs_type); |
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if (err != 0) |
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pr_warn("failed to unregister filesystem "); |
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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"); coda_sysctl_clean(); coda_destroy_inodecache(); } module_init(init_coda); module_exit(exit_coda); |