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1// SPDX-License-Identifier: GPL-2.0-or-later2/*3 * An implementation of a loadable kernel mode driver providing4 * multiple kernel/user space bidirectional communications links.5 *6 * Author: Alan Cox <alan@lxorguk.ukuu.org.uk>7 * 8 * Adapted to become the Linux 2.0 Coda pseudo device9 * Peter Braam <braam@maths.ox.ac.uk> 10 * Michael Callahan <mjc@emmy.smith.edu> 11 *12 * Changes for Linux 2.113 * Copyright (c) 1997 Carnegie-Mellon University14 */15 16#include <linux/module.h>17#include <linux/errno.h>18#include <linux/kernel.h>19#include <linux/major.h>20#include <linux/time.h>21#include <linux/sched/signal.h>22#include <linux/slab.h>23#include <linux/ioport.h>24#include <linux/fcntl.h>25#include <linux/delay.h>26#include <linux/skbuff.h>27#include <linux/proc_fs.h>28#include <linux/vmalloc.h>29#include <linux/fs.h>30#include <linux/file.h>31#include <linux/poll.h>32#include <linux/init.h>33#include <linux/list.h>34#include <linux/mutex.h>35#include <linux/device.h>36#include <linux/pid_namespace.h>37#include <asm/io.h>38#include <linux/uaccess.h>39 40#include <linux/coda.h>41#include "coda_psdev.h"42#include "coda_linux.h"43 44#include "coda_int.h"45 46/* statistics */47int coda_hard; /* allows signals during upcalls */48unsigned long coda_timeout = 30; /* .. secs, then signals will dequeue */49 50 51struct venus_comm coda_comms[MAX_CODADEVS];52static struct class *coda_psdev_class;53 54/*55 * Device operations56 */57 58static __poll_t coda_psdev_poll(struct file *file, poll_table * wait)59{60 struct venus_comm *vcp = (struct venus_comm *) file->private_data;61 __poll_t mask = EPOLLOUT | EPOLLWRNORM;62 63 poll_wait(file, &vcp->vc_waitq, wait);64 mutex_lock(&vcp->vc_mutex);65 if (!list_empty(&vcp->vc_pending))66 mask |= EPOLLIN | EPOLLRDNORM;67 mutex_unlock(&vcp->vc_mutex);68 69 return mask;70}71 72static long coda_psdev_ioctl(struct file * filp, unsigned int cmd, unsigned long arg)73{74 unsigned int data;75 76 switch(cmd) {77 case CIOC_KERNEL_VERSION:78 data = CODA_KERNEL_VERSION;79 return put_user(data, (int __user *) arg);80 default:81 return -ENOTTY;82 }83 84 return 0;85}86 87/*88 * Receive a message written by Venus to the psdev89 */90 91static ssize_t coda_psdev_write(struct file *file, const char __user *buf, 92 size_t nbytes, loff_t *off)93{94 struct venus_comm *vcp = (struct venus_comm *) file->private_data;95 struct upc_req *req = NULL;96 struct upc_req *tmp;97 struct list_head *lh;98 struct coda_in_hdr hdr;99 ssize_t retval = 0, count = 0;100 int error;101 102 /* make sure there is enough to copy out the (opcode, unique) values */103 if (nbytes < (2 * sizeof(u_int32_t)))104 return -EINVAL;105 106 /* Peek at the opcode, uniquefier */107 if (copy_from_user(&hdr, buf, 2 * sizeof(u_int32_t)))108 return -EFAULT;109 110 if (DOWNCALL(hdr.opcode)) {111 union outputArgs *dcbuf;112 int size = sizeof(*dcbuf);113 114 if ( nbytes < sizeof(struct coda_out_hdr) ) {115 pr_warn("coda_downcall opc %d uniq %d, not enough!\n",116 hdr.opcode, hdr.unique);117 count = nbytes;118 goto out;119 }120 if ( nbytes > size ) {121 pr_warn("downcall opc %d, uniq %d, too much!",122 hdr.opcode, hdr.unique);123 nbytes = size;124 }125 126 dcbuf = vmemdup_user(buf, nbytes);127 if (IS_ERR(dcbuf)) {128 retval = PTR_ERR(dcbuf);129 goto out;130 }131 132 /* what downcall errors does Venus handle ? */133 error = coda_downcall(vcp, hdr.opcode, dcbuf, nbytes);134 135 kvfree(dcbuf);136 if (error) {137 pr_warn("%s: coda_downcall error: %d\n",138 __func__, error);139 retval = error;140 goto out;141 }142 count = nbytes;143 goto out;144 }145 146 /* Look for the message on the processing queue. */147 mutex_lock(&vcp->vc_mutex);148 list_for_each(lh, &vcp->vc_processing) {149 tmp = list_entry(lh, struct upc_req , uc_chain);150 if (tmp->uc_unique == hdr.unique) {151 req = tmp;152 list_del(&req->uc_chain);153 break;154 }155 }156 mutex_unlock(&vcp->vc_mutex);157 158 if (!req) {159 pr_warn("%s: msg (%d, %d) not found\n",160 __func__, hdr.opcode, hdr.unique);161 retval = -ESRCH;162 goto out;163 }164 165 /* move data into response buffer. */166 if (req->uc_outSize < nbytes) {167 pr_warn("%s: too much cnt: %d, cnt: %ld, opc: %d, uniq: %d.\n",168 __func__, req->uc_outSize, (long)nbytes,169 hdr.opcode, hdr.unique);170 nbytes = req->uc_outSize; /* don't have more space! */171 }172 if (copy_from_user(req->uc_data, buf, nbytes)) {173 req->uc_flags |= CODA_REQ_ABORT;174 wake_up(&req->uc_sleep);175 retval = -EFAULT;176 goto out;177 }178 179 /* adjust outsize. is this useful ?? */180 req->uc_outSize = nbytes;181 req->uc_flags |= CODA_REQ_WRITE;182 count = nbytes;183 184 /* Convert filedescriptor into a file handle */185 if (req->uc_opcode == CODA_OPEN_BY_FD) {186 struct coda_open_by_fd_out *outp =187 (struct coda_open_by_fd_out *)req->uc_data;188 if (!outp->oh.result) {189 outp->fh = fget(outp->fd);190 if (!outp->fh)191 return -EBADF;192 }193 }194 195 wake_up(&req->uc_sleep);196out:197 return(count ? count : retval); 198}199 200/*201 * Read a message from the kernel to Venus202 */203 204static ssize_t coda_psdev_read(struct file * file, char __user * buf, 205 size_t nbytes, loff_t *off)206{207 DECLARE_WAITQUEUE(wait, current);208 struct venus_comm *vcp = (struct venus_comm *) file->private_data;209 struct upc_req *req;210 ssize_t retval = 0, count = 0;211 212 if (nbytes == 0)213 return 0;214 215 mutex_lock(&vcp->vc_mutex);216 217 add_wait_queue(&vcp->vc_waitq, &wait);218 set_current_state(TASK_INTERRUPTIBLE);219 220 while (list_empty(&vcp->vc_pending)) {221 if (file->f_flags & O_NONBLOCK) {222 retval = -EAGAIN;223 break;224 }225 if (signal_pending(current)) {226 retval = -ERESTARTSYS;227 break;228 }229 mutex_unlock(&vcp->vc_mutex);230 schedule();231 mutex_lock(&vcp->vc_mutex);232 }233 234 set_current_state(TASK_RUNNING);235 remove_wait_queue(&vcp->vc_waitq, &wait);236 237 if (retval)238 goto out;239 240 req = list_entry(vcp->vc_pending.next, struct upc_req,uc_chain);241 list_del(&req->uc_chain);242 243 /* Move the input args into userspace */244 count = req->uc_inSize;245 if (nbytes < req->uc_inSize) {246 pr_warn("%s: Venus read %ld bytes of %d in message\n",247 __func__, (long)nbytes, req->uc_inSize);248 count = nbytes;249 }250 251 if (copy_to_user(buf, req->uc_data, count))252 retval = -EFAULT;253 254 /* If request was not a signal, enqueue and don't free */255 if (!(req->uc_flags & CODA_REQ_ASYNC)) {256 req->uc_flags |= CODA_REQ_READ;257 list_add_tail(&(req->uc_chain), &vcp->vc_processing);258 goto out;259 }260 261 kvfree(req->uc_data);262 kfree(req);263out:264 mutex_unlock(&vcp->vc_mutex);265 return (count ? count : retval);266}267 268static int coda_psdev_open(struct inode * inode, struct file * file)269{270 struct venus_comm *vcp;271 int idx, err;272 273 if (task_active_pid_ns(current) != &init_pid_ns)274 return -EINVAL;275 276 if (current_user_ns() != &init_user_ns)277 return -EINVAL;278 279 idx = iminor(inode);280 if (idx < 0 || idx >= MAX_CODADEVS)281 return -ENODEV;282 283 err = -EBUSY;284 vcp = &coda_comms[idx];285 mutex_lock(&vcp->vc_mutex);286 287 if (!vcp->vc_inuse) {288 vcp->vc_inuse++;289 290 INIT_LIST_HEAD(&vcp->vc_pending);291 INIT_LIST_HEAD(&vcp->vc_processing);292 init_waitqueue_head(&vcp->vc_waitq);293 vcp->vc_sb = NULL;294 vcp->vc_seq = 0;295 296 file->private_data = vcp;297 err = 0;298 }299 300 mutex_unlock(&vcp->vc_mutex);301 return err;302}303 304 305static int coda_psdev_release(struct inode * inode, struct file * file)306{307 struct venus_comm *vcp = (struct venus_comm *) file->private_data;308 struct upc_req *req, *tmp;309 310 if (!vcp || !vcp->vc_inuse ) {311 pr_warn("%s: Not open.\n", __func__);312 return -1;313 }314 315 mutex_lock(&vcp->vc_mutex);316 317 /* Wakeup clients so they can return. */318 list_for_each_entry_safe(req, tmp, &vcp->vc_pending, uc_chain) {319 list_del(&req->uc_chain);320 321 /* Async requests need to be freed here */322 if (req->uc_flags & CODA_REQ_ASYNC) {323 kvfree(req->uc_data);324 kfree(req);325 continue;326 }327 req->uc_flags |= CODA_REQ_ABORT;328 wake_up(&req->uc_sleep);329 }330 331 list_for_each_entry_safe(req, tmp, &vcp->vc_processing, uc_chain) {332 list_del(&req->uc_chain);333 334 req->uc_flags |= CODA_REQ_ABORT;335 wake_up(&req->uc_sleep);336 }337 338 file->private_data = NULL;339 vcp->vc_inuse--;340 mutex_unlock(&vcp->vc_mutex);341 return 0;342}343 344 345static const struct file_operations coda_psdev_fops = {346 .owner = THIS_MODULE,347 .read = coda_psdev_read,348 .write = coda_psdev_write,349 .poll = coda_psdev_poll,350 .unlocked_ioctl = coda_psdev_ioctl,351 .open = coda_psdev_open,352 .release = coda_psdev_release,353 .llseek = noop_llseek,354};355 356static int __init init_coda_psdev(void)357{358 int i, err = 0;359 if (register_chrdev(CODA_PSDEV_MAJOR, "coda", &coda_psdev_fops)) {360 pr_err("%s: unable to get major %d\n",361 __func__, CODA_PSDEV_MAJOR);362 return -EIO;363 }364 coda_psdev_class = class_create("coda");365 if (IS_ERR(coda_psdev_class)) {366 err = PTR_ERR(coda_psdev_class);367 goto out_chrdev;368 } 369 for (i = 0; i < MAX_CODADEVS; i++) {370 mutex_init(&(&coda_comms[i])->vc_mutex);371 device_create(coda_psdev_class, NULL,372 MKDEV(CODA_PSDEV_MAJOR, i), NULL, "cfs%d", i);373 }374 coda_sysctl_init();375 goto out;376 377out_chrdev:378 unregister_chrdev(CODA_PSDEV_MAJOR, "coda");379out:380 return err;381}382 383MODULE_AUTHOR("Jan Harkes, Peter J. Braam");384MODULE_DESCRIPTION("Coda Distributed File System VFS interface");385MODULE_ALIAS_CHARDEV_MAJOR(CODA_PSDEV_MAJOR);386MODULE_LICENSE("GPL");387MODULE_VERSION("7.2");388 389static int __init init_coda(void)390{391 int status;392 int i;393 394 status = coda_init_inodecache();395 if (status)396 goto out2;397 status = init_coda_psdev();398 if ( status ) {399 pr_warn("Problem (%d) in init_coda_psdev\n", status);400 goto out1;401 }402 403 status = register_filesystem(&coda_fs_type);404 if (status) {405 pr_warn("failed to register filesystem!\n");406 goto out;407 }408 return 0;409out:410 for (i = 0; i < MAX_CODADEVS; i++)411 device_destroy(coda_psdev_class, MKDEV(CODA_PSDEV_MAJOR, i));412 class_destroy(coda_psdev_class);413 unregister_chrdev(CODA_PSDEV_MAJOR, "coda");414 coda_sysctl_clean();415out1:416 coda_destroy_inodecache();417out2:418 return status;419}420 421static void __exit exit_coda(void)422{423 int err, i;424 425 err = unregister_filesystem(&coda_fs_type);426 if (err != 0)427 pr_warn("failed to unregister filesystem\n");428 for (i = 0; i < MAX_CODADEVS; i++)429 device_destroy(coda_psdev_class, MKDEV(CODA_PSDEV_MAJOR, i));430 class_destroy(coda_psdev_class);431 unregister_chrdev(CODA_PSDEV_MAJOR, "coda");432 coda_sysctl_clean();433 coda_destroy_inodecache();434}435 436module_init(init_coda);437module_exit(exit_coda);438 439