Add preliminary support for more recent kernel (~4.15)

It is currently building with a Debian 4.15.11-1, but hasn't been tested
and is expecting to crash really hard. Do no try unless you are ready to
hard crash your system. It should support most version between the
~2.6.32 and this 4.15.11.

README.markdown

@@ -6,12 +6,16 @@ FUSD: A Linux Framework for User-Space Devices
 
 This is FUSD snapshot 20110401, released 18 January 2012. This fork is based
 on the found on the xiph.org SVN tracker. ( http://svn.xiph.org/trunk/fusd ) 
-They seems to no longuer update this tool (since 11 January 2007) and since it
-longuer compile with recent Linux kernel (at around 2.6.21) and since I need
-it in personal project, I ported it to newer version (current version is 2.6.32)
+They seems to no longer update this tool (since 11 January 2007) and since it
+longer compile with recent Linux kernel (at around 2.6.21) and since I need
+it in personal project, I ported it to newer version (current version is 2.6.32).
+It is currently no officialy supporting newer kernel, but changes are currently 
+going on to support newer kernel up to 4.15. It is currently building under this
+line, but don't expect it to work.
+ 
 
 Some feature are still missing missing or buggy form the Xiph version (due to
-changes on the kernel source tree), but it's completly useable.
+changes on the kernel source tree), but it is still usable.
 
 The official URL for this fork is:
 
@@ -53,7 +57,7 @@ include the following rule:
 
 5. Verify the fusd devices /dev/fusd/status and /dev/fusd/control
 exist. If the modprobe succeeds but no fusd devices appear,
-doublecheck the udev rule config change and make sure udevd restarted
+double-check the udev rule config change and make sure udevd restarted
 successfully. The kfusd kernel module must be inserted after udev has
 been correctly configured and restarted.
 

include/fusd.h

@@ -66,6 +66,8 @@ __BEGIN_DECLS
 
 #define FUSD_KOR_HACKED_VERSION
 
+#ifndef __KERNEL__
+
 struct fusd_file_info; /* forward decl */
 
 typedef
@@ -105,6 +107,7 @@ struct fusd_file_info {
 
   /* other info might be added later, e.g. state needed to complete
      operations... */
+  pthread_mutex_t lock;
 
   /* request message associated with this call */
   int fd;
@@ -112,8 +115,8 @@ struct fusd_file_info {
 
 } fusd_file_info_t;
 
-
-
+#define FILE_LOCK(__f) pthread_mutex_lock(&__f->lock)
+#define FILE_UNLOCK(__f) pthread_mutex_unlock(&__f->lock)
 
 /*************************** Library Functions ****************************/
 
@@ -278,6 +281,8 @@ static inline int fusd_get_poll_diff_cached_state(struct fusd_file_info *file)
 /* returns static string representing the flagset (e.g. RWE) */
 char *fusd_unparse_flags(int flags);
 
+#endif /* !__KERNEL__ */
+
 #ifndef __KERNEL__
 __END_DECLS
 #endif

include/kfusd.h

@@ -273,7 +273,7 @@ static void fusd_vfree(void *ptr);
 /* Functions like this should be in the kernel, but they are not.  Sigh. */
 # ifdef CONFIG_SMP
 
-#if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,30)
+#if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,35)
 DECLARE_MUTEX(atomic_ops);
 #else
 DEFINE_SEMAPHORE(atomic_ops);

kfusd/kfusd.c

@@ -38,7 +38,7 @@
  * Copyright (c) 2001, Sensoria Corporation
  * Copyright (c) 2002-2003, Regents of the University of California
  * Copyright (c) 2007 Monty and Xiph.Org
- * Copyright (c) 2009-2011 Manoel Trapier <godzil@godzil.net>
+ * Copyright (c) 2009-2012 Manoel Trapier <godzil@godzil.net>
  *
  * $Id: kfusd.c 12354 2007-01-19 17:26:14Z xiphmont $
  */
@@ -78,6 +78,10 @@
 #include <linux/device.h>
 #include <linux/highmem.h>
 
+#if LINUX_VERSION_CODE >= KERNEL_VERSION(4, 11, 0)
+#include <linux/sched/signal.h>
+#endif
+
 #include <asm/atomic.h>
 #include <asm/uaccess.h>
 #include <asm/ioctl.h>
@@ -132,6 +136,23 @@
 #   define CLASS_DEVICE_DESTROY(a, b) device_destroy(a, b)
 #endif
 
+#if LINUX_VERSION_CODE >= KERNEL_VERSION(4, 9, 0)
+//result = GET_USER_PAGES(mmap_instance->fusd_dev->task, mmap_instance->fusd_dev->task->mm,
+//                           mmap_instance->addr + offset, 1, 1, 0, &page, NULL);
+#define GET_USER_PAGES(t,m,s,n,w,f,p,v) get_user_pages_remote(t,m,s,n,(w?FOLL_WRITE:0)|(f?FOLL_FORCE:0),p,v, NULL)
+#elif LINUX_VERSION_CODE >= KERNEL_VERSION(4, 6, 0)
+
+#define GET_USER_PAGES(t,m,s,n,w,f,p,v) get_user_pages_remote(t,m,s,n,w,f,p,v)
+#else
+#define GET_USER_PAGES(t,m,s,n,w,f,p,v) get_user_pages(t,m,s,n,w,f,p,v)
+#endif
+
+#if LINUX_VERSION_CODE >= KERNEL_VERSION(4, 8, 0)
+#define FULL_NAME_HASH(a, b) full_name_hash(0, a, b)
+#else
+#define FULL_NAME_HASH(a, b) full_name_hash(a, b)
+#endif
+
 #if LINUX_VERSION_CODE > KERNEL_VERSION(2,6,19)
 
 struct sysfs_elem_dir
@@ -194,6 +215,11 @@ struct class_private {
 
 #endif
 
+/*
+	struct sysfs_dirent *attr_sd = dentry->d_fsdata;
+	struct kobject *kobj = attr_sd->s_parent->s_dir.kobj;
+*/
+
 static inline struct kobject * to_kobj (struct dentry * dentry)
 {
    struct sysfs_dirent * sd = dentry->d_fsdata;
@@ -201,7 +227,7 @@ static inline struct kobject * to_kobj (struct dentry * dentry)
 #if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,20)
       return ((struct kobject *) sd->s_element );
 #else
-      return ((struct kobject *) sd->s_dir.kobj );
+      return ((struct kobject *) sd->s_parent->s_dir.kobj );
 #endif
    else
       return NULL;
@@ -249,7 +275,8 @@ STATIC DECLARE_WAIT_QUEUE_HEAD (new_device_wait);
 
 /* the list of valid devices, and sem to protect it */
 LIST_HEAD (fusd_devlist_head);
-#if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,30)
+
+#if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,33)
 DECLARE_MUTEX (fusd_devlist_sem);
 #else
 DEFINE_SEMAPHORE (fusd_devlist_sem);
@@ -257,7 +284,7 @@ DEFINE_SEMAPHORE (fusd_devlist_sem);
 
 //#ifdef MODULE_LICENSE
 MODULE_AUTHOR ("Jeremy Elson <jelson@acm.org> (c)2001");
-MODULE_AUTHOR ("Manoel Trapier <godzil@godzil.net> (c)2009-2011");
+MODULE_AUTHOR ("Manoel Trapier <godzil@godzil.net> (c)2009-2012");
 MODULE_LICENSE ("GPL");
 //#endif
 
@@ -315,7 +342,12 @@ STATIC void rdebug_real (char *fmt, ...)
 
 #   define MAX_MEM_DEBUG 10000
 
+
+#if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,30)
 DECLARE_MUTEX (fusd_memdebug_sem);
+#else
+DEFINE_SEMAPHORE (fusd_memdebug_sem);
+#endif
 
 typedef struct
 {
@@ -464,6 +496,7 @@ STATIC inline void free_fusd_msg (fusd_msg_t **fusd_msg)
       VFREE(( *fusd_msg )->data);
       ( *fusd_msg )->data = NULL;
    }
+   RDEBUG(1, "Freeing fusd_msg [%p] then set to NULL", fusd_msg);
    KFREE(*fusd_msg);
    *fusd_msg = NULL;
 }
@@ -835,7 +868,7 @@ STATIC int fusd_fops_call_send (fusd_file_t *fusd_file_arg,
 
    /* fill the rest of the structure */
    fusd_msg->parm.fops_msg.pid = current->pid;
-#if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,29)
+#if LINUX_VERSION_CODE < KERNEL_VERSION(2, 6, 29)
    fusd_msg->parm.fops_msg.uid = current_uid();
    fusd_msg->parm.fops_msg.gid = current_gid();
 #endif
@@ -1137,7 +1170,7 @@ int fusd_dev_add_file (struct file *file, fusd_dev_t *fusd_dev, fusd_file_t **fu
    init_waitqueue_head(&fusd_file->file_wait);
    init_waitqueue_head(&fusd_file->poll_wait);
    INIT_LIST_HEAD(&fusd_file->transactions);
-#if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,30)   
+#if LINUX_VERSION_CODE < KERNEL_VERSION(2, 6, 30)
    init_MUTEX(&fusd_file->file_sem);
    init_MUTEX(&fusd_file->transactions_sem);
 #else
@@ -1699,11 +1732,14 @@ static void fusd_client_mm_open (struct vm_area_struct * vma);
 static void fusd_client_mm_close (struct vm_area_struct * vma);
 
 /* int (*fault)(struct vm_area_struct *vma, struct vm_fault *vmf); */
-#if LINUX_VERSION_CODE > KERNEL_VERSION(2,6,30)
+#if LINUX_VERSION_CODE >= KERNEL_VERSION(4,11,0)
+static int fusd_client_fault (struct vm_fault *vmf);
+#elif LINUX_VERSION_CODE > KERNEL_VERSION(2,6,30)
 static int fusd_client_fault (struct vm_area_struct *vma, struct vm_fault *vmf);
 #else
 static int fusd_client_fault (struct vm_area_struct *vma, struct vm_fault *vmf, int *type);
 #endif
+
 static struct vm_operations_struct fusd_remap_vm_ops ={
                                                        .open = fusd_client_mm_open,
                                                        .close = fusd_client_mm_close,
@@ -1771,7 +1807,7 @@ static int fusd_client_mmap (struct file *file, struct vm_area_struct * vma)
    }
 
    /* and wait for the reply */
-   /* todo: store and retrieve the transid from the interrupted messsage */
+   /* todo: store and retrieve the transid from the interrupted message */
    retval = fusd_fops_call_wait(fusd_file, &reply, transaction);
 
    mmap_instance =
@@ -1788,7 +1824,11 @@ static int fusd_client_mmap (struct file *file, struct vm_area_struct * vma)
 
    vma->vm_private_data = mmap_instance;
    vma->vm_ops = &fusd_remap_vm_ops;
+#if LINUX_VERSION_CODE >= KERNEL_VERSION(3, 7, 0)
+   vma->vm_flags |= (VM_DONTEXPAND | VM_DONTDUMP);
+#else
    vma->vm_flags |= VM_RESERVED;
+#endif
 
    fusd_client_mm_open(vma);
 
@@ -1805,24 +1845,36 @@ invalid_file:
    return -EPIPE;
 }
 
-#if LINUX_VERSION_CODE > KERNEL_VERSION(2,6,30)
+#if LINUX_VERSION_CODE >= KERNEL_VERSION(4, 11, 0)
+static int fusd_client_fault (struct vm_fault *vmf)
+#elif LINUX_VERSION_CODE > KERNEL_VERSION(2, 6, 30)
 static int fusd_client_fault (struct vm_area_struct *vma, struct vm_fault *vmf)
 #else
 static int fusd_client_fault (struct vm_area_struct *vma, struct vm_fault *vmf, int *type)
 #endif
 {
+#if LINUX_VERSION_CODE >= KERNEL_VERSION(4, 11, 0)
+   struct vm_area_struct *vma = vmf->vma;
+#endif
+
    struct fusd_mmap_instance* mmap_instance = (struct fusd_mmap_instance*) vma->vm_private_data;
    unsigned long offset;
    struct page *page = NULL;
    int result;
 
+#if LINUX_VERSION_CODE >= KERNEL_VERSION(4, 10, 0)
+   offset = ( (unsigned long) vmf->address - vma->vm_start ) + ( vma->vm_pgoff << PAGE_SHIFT );
+#else
    offset = ( (unsigned long) vmf->virtual_address - vma->vm_start ) + ( vma->vm_pgoff << PAGE_SHIFT );
+#endif
+
    // todo: worry about size
    if ( offset > mmap_instance->size )
       goto out;
 
    down_read(&mmap_instance->fusd_dev->task->mm->mmap_sem);
-   result = get_user_pages(mmap_instance->fusd_dev->task, mmap_instance->fusd_dev->task->mm, mmap_instance->addr + offset, 1, 1, 0, &page, NULL);
+   result = GET_USER_PAGES(mmap_instance->fusd_dev->task, mmap_instance->fusd_dev->task->mm,
+                           mmap_instance->addr + offset, 1, 1, 0, &page, NULL);
    up_read(&mmap_instance->fusd_dev->task->mm->mmap_sem);
 
 
@@ -2194,9 +2246,12 @@ STATIC int fusd_register_device (fusd_dev_t *fusd_dev,
 
       if ( sysfs )
       {
-	 /* Get FS superblock */
+         /* Get FS superblock */
+#if LINUX_VERSION_CODE >= KERNEL_VERSION(3, 6, 0)
+         sb = sget(sysfs, systest, NULL, 0, NULL);
+#else
          sb = sget(sysfs, systest, NULL, NULL);
-
+#endif
          /* because put_filesystem isn't exported */
          module_put(sysfs->owner);
 
@@ -2209,18 +2264,19 @@ STATIC int fusd_register_device (fusd_dev_t *fusd_dev,
             {
                struct qstr name;
 
-	       /* Search for directory "class" in the root of this filesystem */
+	            /* Search for directory "class" in the root of this filesystem */
                name.name = "class";
                name.len = 5;
-               name.hash = full_name_hash(name.name, name.len);
+               name.hash = FULL_NAME_HASH(name.name, name.len);
+
                classdir = d_lookup(root, &name);
 
                if ( classdir )
                {
-		  /* Found, now search for class wanted name */
+                  /* Found, now search for class wanted name */
                   name.name = register_msg.clazz;
                   name.len = strlen(name.name);
-                  name.hash = full_name_hash(name.name, name.len);
+                  name.hash = FULL_NAME_HASH(name.name, name.len);
                   classdir2 = d_lookup(classdir, &name);
 
                   if ( classdir2 )
@@ -2229,15 +2285,16 @@ STATIC int fusd_register_device (fusd_dev_t *fusd_dev,
                      struct kobject *ko = to_kobj(classdir2);
                      sys_class = ( ko ? to_class(ko)->class : NULL );
 
-	             if ( sys_class )
-		     {
+#if 0
+                     if ( sys_class )
+                     {
                         /* W T F ???? Using an existing sys_class will led to a NULL pointer crash
                          * during device creation.. Need more investigation, this comportement is clearly not
                          * normal. */
-		        RDEBUG(1, "ERROR: Using existing class name is currently unsported !!!");
-			goto register_failed4;
-		     }
-
+                        RDEBUG(1, "ERROR: Using existing class name is currently unsported !!!");
+                        goto register_failed4;
+                     }
+#endif
                      if ( !sys_class )
                         RDEBUG(2, "WARNING: sysfs entry for %s has no kobject!\n", register_msg.clazz);
                   }
@@ -2630,7 +2687,7 @@ STATIC ssize_t fusd_write (struct file *file,
    RDEBUG(1, "%s: [%p:%p:%d:%p] [sl: %d]!!", __func__, file, buffer, length, offset, sizeof (fusd_msg_t ));
    return fusd_process_write(file, buffer, length, NULL, 0);
 }
-
+#ifndef HAVE_UNLOCKED_IOCTL
 STATIC ssize_t fusd_writev (struct file *file,
                             const struct iovec *iov,
                             unsigned long count,
@@ -2646,6 +2703,48 @@ STATIC ssize_t fusd_writev (struct file *file,
                              iov[0].iov_base, iov[0].iov_len,
                              iov[1].iov_base, iov[1].iov_len);
 }
+#elif LINUX_VERSION_CODE >= KERNEL_VERSION(4, 1, 0)
+ssize_t fusd_write_iter (struct kiocb *iocb, struct iov_iter *iov)
+{
+   unsigned long count = iov_iter_count(iov);
+   char *msg, *data;
+   size_t msg_len, data_len;
+
+   if ( count != 2 )
+   {
+      RDEBUG(2, "fusd_writev: got illegal iov count of %ld", count);
+      return -EINVAL;
+   }
+
+   msg = iov->iov->iov_base + iov->iov_offset;
+   msg_len = iov_iter_single_seg_count(iov);
+
+   iov_iter_advance(iov, msg_len);
+
+   data = iov->iov->iov_base + iov->iov_offset;
+   data_len = iov_iter_single_seg_count(iov);
+
+   return fusd_process_write(iocb->ki_filp,
+                             msg, msg_len,
+                             data, data_len);
+}
+#else
+STATIC ssize_t fusd_aio_write (struct kiocb *iocb,
+                               const struct iovec *iov, 
+                               unsigned long count,
+                               loff_t offset)                            
+{
+   if ( count != 2 )
+   {
+      RDEBUG(2, "fusd_writev: got illegal iov count of %ld", count);
+      return -EINVAL;
+   }
+
+   return fusd_process_write(iocb->ki_filp,
+                             iov[0].iov_base, iov[0].iov_len,
+                             iov[1].iov_base, iov[1].iov_len);
+}
+#endif
 
 #ifndef HAVE_UNLOCKED_IOCTL
 STATIC int fusd_ioctl (struct inode *inode, struct file *file,
@@ -2655,6 +2754,7 @@ STATIC long fusd_unlocked_ioctl (struct file *file,
                        unsigned int cmd, unsigned long arg)
 #endif
 {
+#if 0
    void __user *argp = (void __user *) arg;
    struct iovec iov;
 
@@ -2672,6 +2772,7 @@ STATIC long fusd_unlocked_ioctl (struct file *file,
          return -EIO;
       }
    }
+#endif
    RDEBUG(2, "%s: got illegal ioctl #%08X# Or ARG is null [%p]", __func__, cmd, argp);
    return -EINVAL;
 }
@@ -2882,7 +2983,11 @@ STATIC struct file_operations fusd_fops = {
                                            .open = fusd_open,
                                            .read = fusd_read,
                                            .write = fusd_write,
-                                           //writev:   fusd_writev,
+#if LINUX_VERSION_CODE >= KERNEL_VERSION(4, 1, 0)
+                                           .write_iter = fusd_write_iter,
+#else
+                                           .aio_write = fusd_aio_write,
+#endif
                                            .unlocked_ioctl = fusd_unlocked_ioctl,
                                            .release = fusd_release,
                                            .poll = fusd_poll,

libfusd/libfusd.c

@@ -27,7 +27,7 @@
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  *
  */
- 
+
 
 /*
  * fusd userspace library: functions that know how to properly talk
@@ -53,6 +53,11 @@ char libfusd_c_id[] = "$Id: libfusd.c 12351 2007-01-19 07:22:54Z xiphmont $";
 #include <string.h>
 #include <time.h>
 
+#include <pthread.h>
+
+#include <unistd.h>
+#include <sys/syscall.h>
+
 #include "fusd.h"
 #include "fusd_msg.h"
 
@@ -72,7 +77,7 @@ char *dev_root = NULL;
  * struct for each fusd fd.
  */
 static fusd_file_operations_t fusd_fops_set[FD_SETSIZE];
-fusd_file_operations_t null_fops = { NULL };
+fusd_file_operations_t null_fops = { NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL };
 
 /*
  * accessor macros
@@ -99,7 +104,8 @@ void fusd_init()
 {
   static int fusd_init_needed = 1;
 
-  if (fusd_init_needed) {
+  if (fusd_init_needed)
+  {
     int i;
 
     fusd_init_needed = 0;
@@ -123,7 +129,8 @@ int fusd_register(const char *name, const char* clazz, const char* devname, mode
   fusd_init();
 
   /* make sure the name is valid and we have a valid set of fops... */
-  if (name == NULL || fops == NULL) {
+  if (name == NULL || fops == NULL)
+  {
     fprintf(stderr, "fusd_register: invalid name or fops argument\n");
     retval = -EINVAL;
     goto done;
@@ -134,27 +141,33 @@ int fusd_register(const char *name, const char* clazz, const char* devname, mode
    * to register are SKIP_PREFIX (usually "/dev/"), skip over them.
    */
   if (dev_root != NULL && strlen(name) > strlen(dev_root) &&
-      !strncmp(name, dev_root, strlen(dev_root))) {
+      !strncmp(name, dev_root, strlen(dev_root)))
+  {
     name += strlen(dev_root);
   }
 
-  if (strlen(name) > FUSD_MAX_NAME_LENGTH) {
-    fprintf(stderr, "name '%s' too long, sorry :(", name);
+  if (strlen(name) > FUSD_MAX_NAME_LENGTH)
+  {
+    fprintf(stderr, "libfusd: name '%s' too long, sorry :(\n", name);
     retval = -EINVAL;
     goto done;
   }
 
   /* open the fusd control channel */
-  if ((fd = open(FUSD_CONTROL_DEVNAME, O_RDWR | O_NONBLOCK)) < 0) {
+  if ((fd = open(FUSD_CONTROL_DEVNAME, O_RDWR | O_NONBLOCK)) < 0)
+  {
 
     /* if the problem is that /dev/fusd does not exist, return the
      * message "Package not installed", which is hopefully more
      * illuminating than "no such file or directory" */
-    if (errno == ENOENT) {
+    if (errno == ENOENT)
+    {
       fprintf(stderr, "libfusd: %s does not exist; ensure FUSD's kernel module is installed\n",
 	      FUSD_CONTROL_DEVNAME);
       retval = -ENOPKG;
-    } else {
+    }
+    else
+    {
       perror("libfusd: trying to open FUSD control channel");
       retval = -errno;
     }
@@ -162,7 +175,8 @@ int fusd_register(const char *name, const char* clazz, const char* devname, mode
   }
 
   /* fd in use? */
-  if (FUSD_FD_VALID(fd)) {
+  if (FUSD_FD_VALID(fd))
+  {
     retval = -EBADF;
     goto done;
   }
@@ -179,7 +193,8 @@ int fusd_register(const char *name, const char* clazz, const char* devname, mode
   message.parm.register_msg.device_info = device_info;
 
   /* make the request */
-  if (write(fd, &message, sizeof(fusd_msg_t)) < 0) {
+  if (write(fd, &message, sizeof(fusd_msg_t)) < 0)
+  {
     retval = -errno;
     goto done;
   }
@@ -190,34 +205,38 @@ int fusd_register(const char *name, const char* clazz, const char* devname, mode
 
   /* success! */
  done:
-  if (retval < 0) {
+  if (retval < 0)
+  {
     if (fd >= 0)
       close(fd);
     errno = -retval;
     retval = -1;
-  } else {
+  }
+  else
+  {
     errno = 0;
     retval = fd;
   }
-
   return retval;
 }
 
-
 int fusd_unregister(int fd)
 {
-  if (FUSD_FD_VALID(fd)) {
+  int ret = -1;
+  if (FUSD_FD_VALID(fd))
+  {
     /* clear fd location */
     FUSD_SET_FOPS(fd, &null_fops);
     FD_CLR(fd, &fusd_fds);
     /* close */
-    return close(fd);
+    ret = close(fd);
   }
-  
-  else {
+  else
+  {
     errno = EBADF;
-    return -1;
   }
+
+  return ret;
 }
 
 
@@ -236,21 +255,25 @@ void fusd_run(void)
   int i;
 
   /* locate maxmimum fd in use */
-  for (maxfd=0, i=0; i < FD_SETSIZE; i++) {
-    if (FD_ISSET(i, &fusd_fds)) {
+  for (maxfd=0, i=0; i < FD_SETSIZE; i++)
+  {
+    if (FD_ISSET(i, &fusd_fds))
+    {
       maxfd = i;
     }
   }
   maxfd++;
 
 
-  while (1) {
+  while (1)
+  {
     /* select */
     memmove(&tfds, &fusd_fds, sizeof(fd_set));
     status = select(maxfd, &tfds, NULL, NULL, NULL);
 
     /* error? */
-    if (status < 0) {
+    if (status < 0)
+    {
       perror("libfusd: fusd_run: error on select");
       continue;
     }
@@ -258,14 +281,13 @@ void fusd_run(void)
     /* readable? */
     for (i = 0; i < maxfd; i++)
       if (FD_ISSET(i, &tfds))
-	fusd_dispatch(i);
+
+    fusd_dispatch(i);
   }
 }
 
-
 /************************************************************************/
 
-
 /* reads a fusd kernel-to-userspace message from fd, and puts a
  * fusd_msg into the memory pointed to by msg (we assume we are passed
  * a buffer managed by the caller).  if there is a data portion to the
@@ -274,39 +296,51 @@ void fusd_run(void)
  * managed by the caller. */
 static int fusd_get_message(int fd, fusd_msg_t *msg)
 {
+  int ret;
+
   /* read the header part into the kernel */
-  if (read(fd, msg, sizeof(fusd_msg_t)) < 0) {
+  if (read(fd, msg, sizeof(fusd_msg_t)) < 0)
+  {
     if (errno != EAGAIN)
       perror("error talking to FUSD control channel on header read");
-    return -errno;
+    ret = -errno;
+    goto exit;
   }
   msg->data = NULL; /* pointers in kernelspace have no meaning */
 
-  if (msg->magic != FUSD_MSG_MAGIC) {
-    fprintf(stderr, "libfusd magic number failure\n");
-    return -EINVAL;
+  if (msg->magic != FUSD_MSG_MAGIC)
+  {
+    fprintf(stderr, "libfusd: magic number failure\n");
+    ret = -EINVAL;
+    goto exit;
   }
 
   /* if there's a data part to the message, read it from the kernel. */
-  if (msg->datalen) {
-    if ((msg->data = malloc(msg->datalen + 1)) == NULL) {
+  if (msg->datalen)
+  {
+    if ((msg->data = malloc(msg->datalen + 1)) == NULL)
+    {
       fprintf(stderr, "libfusd: can't allocate memory\n");
-      return -ENOMEM;  /* this is bad, we are now unsynced */
+      ret = -ENOMEM;  /* this is bad, we are now unsynced */
+      goto exit;
     }
 
-    if (read(fd, msg->data, msg->datalen) < 0) {
+    if (read(fd, msg->data, msg->datalen) < 0)
+    {
       perror("error talking to FUSD control channel on data read");
       free(msg->data);
       msg->data = NULL;
-      return -EIO;
+      ret = -EIO;
+      goto exit;
     }
 
     /* For convenience, we now ensure that the byte *after* the buffer
      * is set to 0.  (Note we malloc'd one extra byte above.) */
     msg->data[msg->datalen] = '\0';
   }
-
-  return 0;
+  ret = 0;
+exit:
+  return ret;
 }
 
 
@@ -318,11 +352,14 @@ void fusd_fdset_add(fd_set *set, int *max)
 {
   int i;
 
-  for (i = 0; i < FD_SETSIZE; i++) {
-    if (FD_ISSET(i, &fusd_fds)) {
+  for (i = 0; i < FD_SETSIZE; i++)
+  {
+    if (FD_ISSET(i, &fusd_fds))
+    {
       FD_SET(i, set);
-      if (i > *max) {
-	*max = i;
+      if (i > *max)
+      {
+        *max = i;
       }
     }
   }
@@ -340,6 +377,7 @@ void fusd_dispatch_fdset(fd_set *set)
   for (i = 0; i < FD_SETSIZE; i++)
     if (FD_ISSET(i, set) && FD_ISSET(i, &fusd_fds))
       fusd_dispatch(i);
+
 }
 
 
@@ -361,14 +399,16 @@ static int fusd_dispatch_one(int fd, fusd_file_operations_t *fops)
   int user_retval = 0;    /* returned to the user who made the syscall */
 
   /* check for valid, look up ops */
-  if (fops == NULL) {
+  if (fops == NULL)
+  {
     fprintf(stderr, "fusd_dispatch: no fops provided!\n");
     driver_retval = -EBADF;
     goto out_noreply;
   }
 
   /* allocate memory for fusd_msg_t */
-  if ((msg = malloc(sizeof(fusd_msg_t))) == NULL) {
+  if ((msg = malloc(sizeof(fusd_msg_t))) == NULL)
+  {
     driver_retval = -ENOMEM;
     fprintf(stderr, "libfusd: can't allocate memory\n");
     goto out_noreply;
@@ -381,7 +421,8 @@ static int fusd_dispatch_one(int fd, fusd_file_operations_t *fops)
 
   /* allocate file info struct */
   file = malloc(sizeof(fusd_file_info_t));
-  if (NULL == file) {
+  if (NULL == file)
+  {
     fprintf(stderr, "libfusd: can't allocate memory\n");
     driver_retval = -ENOMEM;
     goto out_noreply;
@@ -389,6 +430,11 @@ static int fusd_dispatch_one(int fd, fusd_file_operations_t *fops)
 
   /* fill the file info struct */
   memset(file, '\0', sizeof(fusd_file_info_t));
+
+  pthread_mutex_init(&file->lock, NULL);
+
+  FILE_LOCK(file);
+
   file->fd = fd;
   file->device_info = msg->parm.fops_msg.device_info;
   file->private_data = msg->parm.fops_msg.private_info;
@@ -398,49 +444,62 @@ static int fusd_dispatch_one(int fd, fusd_file_operations_t *fops)
   file->gid = msg->parm.fops_msg.gid;
   file->fusd_msg = msg;  
 
+  FILE_UNLOCK(file);
+
   /* right now we only handle fops requests */
   if (msg->cmd != FUSD_FOPS_CALL && msg->cmd != FUSD_FOPS_NONBLOCK &&
-      msg->cmd != FUSD_FOPS_CALL_DROPREPLY) {
+      msg->cmd != FUSD_FOPS_CALL_DROPREPLY)
+  {
     fprintf(stderr, "libfusd: got unknown msg->cmd from kernel\n");
     user_retval = -EINVAL;
     goto send_reply;
   }
-  
+
   /* dispatch on operation type */
   user_retval = -ENOSYS;
   //printf("dispatch_one: subcmd: %d - ", msg->subcmd);
   
-  switch (msg->subcmd) {
+
+  switch (msg->subcmd)
+  {
   case FUSD_OPEN:
     //printf("FUSD_OPEN\n");
     if (fops && fops->open)
       user_retval = fops->open(file);
     break;
+
   case FUSD_CLOSE:
     //printf("FUSD_CLOSE\n");
     if (fops && fops->close)
       user_retval = fops->close(file);
     break;
+
   case FUSD_READ:
     //printf("FUSD_READ\n");
     /* allocate a buffer and make the call */
-    if (fops && fops->read) {
-      if ((msg->data = malloc(msg->parm.fops_msg.length)) == NULL) {
-	user_retval = -ENOMEM;
-	fprintf(stderr, "libfusd: can't allocate memory\n");
-      } else {
-	msg->datalen = msg->parm.fops_msg.length;
-	user_retval = fops->read(file, msg->data, msg->datalen,
-				 &msg->parm.fops_msg.offset);
+    if (fops && fops->read)
+    {
+      if ((msg->data = malloc(msg->parm.fops_msg.length)) == NULL)
+      {
+        user_retval = -ENOMEM;
+        fprintf(stderr, "libfusd: can't allocate memory\n");
+      }
+      else
+      {
+        msg->datalen = msg->parm.fops_msg.length;
+        user_retval = fops->read(file, msg->data, msg->datalen,
+                                 &msg->parm.fops_msg.offset);
       }
     }
     break;
+
   case FUSD_WRITE:
     //printf("FUSD_WRITE\n");
     if (fops && fops->write)
       user_retval = fops->write(file, msg->data, msg->datalen,
 				&msg->parm.fops_msg.offset);
     break;
+
   case FUSD_MMAP:
     //printf("FUSD_MMAP\n");
     if (fops && fops->mmap)
@@ -449,54 +508,58 @@ static int fusd_dispatch_one(int fd, fusd_file_operations_t *fops)
                                &msg->parm.fops_msg.arg.ptr_arg, &msg->parm.fops_msg.length);
     }
     break;
+
   case FUSD_IOCTL:
     //printf("FUSD_IOCTL\n");
-    if (fops && fops->ioctl) {
+    if (fops && fops->ioctl)
+    {
       /* in the case of an ioctl read, allocate a buffer for the
        * driver to write to, IF there isn't already a buffer.  (there
        * might already be a buffer if this is a read+write) */
       if ((_IOC_DIR(msg->parm.fops_msg.cmd) & _IOC_READ) &&
-	  msg->data == NULL) {
-	msg->datalen = _IOC_SIZE(msg->parm.fops_msg.cmd);
-	if ((msg->data = malloc(msg->datalen)) == NULL) {
-	  user_retval = -ENOMEM;
-	  break;
-	}
+           msg->data == NULL)
+      {
+        msg->datalen = _IOC_SIZE(msg->parm.fops_msg.cmd);
+        if ((msg->data = malloc(msg->datalen)) == NULL)
+        {
+          user_retval = -ENOMEM;
+          break;
+        }
       }
       if (msg->data != NULL)
-	user_retval = fops->ioctl(file, msg->parm.fops_msg.cmd, msg->data);
+        user_retval = fops->ioctl(file, msg->parm.fops_msg.cmd, msg->data);
       else
-	user_retval = fops->ioctl(file, msg->parm.fops_msg.cmd,
-				  (void *) msg->parm.fops_msg.arg.ptr_arg);
+        user_retval = fops->ioctl(file, msg->parm.fops_msg.cmd,
+                                  (void *) msg->parm.fops_msg.arg.ptr_arg);
     }
     break;
-    
+
   case FUSD_POLL_DIFF:
      //printf("FUSD_POLL_DIFF\n");
     /* This callback requests notification when an event occurs on a file,
      * e.g. becoming readable or writable */
     if (fops && fops->poll_diff)
       user_retval = fops->poll_diff(file, msg->parm.fops_msg.cmd);
-    break;    
-  
+    break;
+
   case FUSD_UNBLOCK:
     //printf("FUSD_UNBLOCK\n");
     /* This callback is called when a system call is interrupted */
     if (fops && fops->unblock)
-      user_retval = fops->unblock(file);    
+      user_retval = fops->unblock(file);
     break;
-    
+
   default:
     fprintf(stderr, "libfusd: Got unsupported operation\n");
     user_retval = -ENOSYS;
     break;
   }
-  
+
   goto send_reply;
 
 
   /* out_noreply is only used for handling errors */
- out_noreply:
+out_noreply:
   if (msg->data != NULL)
     free(msg->data);
   if (msg != NULL)
@@ -504,21 +567,26 @@ static int fusd_dispatch_one(int fd, fusd_file_operations_t *fops)
   goto done;
 
   /* send_reply is only used for success */
- send_reply:
-  if (-user_retval <= 0xff) {
+send_reply:
+  if (-user_retval <= 0xff)
+  {
     /* 0xff is the maximum legal return value (?) - return val to user */
     driver_retval = fusd_return(file, user_retval);
-  } else {
+  }
+  else
+  {
     /* if we got a FUSD_NOREPLY, don't free the msg structure */
     driver_retval = 0;
   }
 
   /* this is common to both errors and success */
- done:
-  if (driver_retval < 0) {
+done:
+  if (driver_retval < 0)
+  {
     errno = -driver_retval;
     driver_retval = -1;
   }
+
   return driver_retval;
 }
 
@@ -538,7 +606,8 @@ void fusd_dispatch(int fd)
   fusd_file_operations_t *fops = NULL;
 
   /* make sure we have a valid FD, and get its fops structure */
-  if (!FUSD_FD_VALID(fd)) {
+  if (!FUSD_FD_VALID(fd))
+  {
     errno = EBADF;
     retval = -1;
     fprintf(stderr, "libfusd: not a valid FUSD FD\n");
@@ -547,7 +616,8 @@ void fusd_dispatch(int fd)
   fops = FUSD_GET_FOPS(fd);
 
   /* now keep dispatching until a dispatch returns an error */
-  do {
+  do
+  {
     retval = fusd_dispatch_one(fd, fops);
 
     if (retval >= 0)
@@ -557,14 +627,16 @@ void fusd_dispatch(int fd)
   /* if we've dispatched at least one message successfully, and then
    * stopped because of EAGAIN - do not report an error.  this is the
    * common case. */
-  if (num_dispatches > 0 && errno == EAGAIN) {
+  if (num_dispatches > 0 && errno == EAGAIN)
+  {
     retval = 0;
     errno = 0;
   }
 
  out:
   if (retval < 0 && errno != EPIPE)
-    fprintf(stderr, "libfusd: fusd_dispatch error on fd %d: [%d] %m \n", fd, retval);
+    fprintf(stderr, "libfusd: fusd_dispatch error on fd %d: [%d] %m\n", fd, retval);
+
 }
 
 
@@ -578,13 +650,26 @@ void fusd_dispatch(int fd)
  */
 void fusd_destroy(struct fusd_file_info *file)
 {
-  if (file == NULL)
-    return;
+   if (file == NULL)
+      return;
 
-  if (file->fusd_msg->data != NULL)
-    free(file->fusd_msg->data);
-  free(file->fusd_msg);
-  free(file);
+   FILE_LOCK(file);
+
+   if (file->fusd_msg != NULL)
+   {
+      if (file->fusd_msg->data != NULL)
+      {
+         free(file->fusd_msg->data);
+         file->fusd_msg->data = NULL;
+      }
+      free(file->fusd_msg);
+      file->fusd_msg = NULL;
+   }
+   FILE_UNLOCK(file);
+
+   pthread_mutex_destroy(&file->lock);
+
+   free(file);
 }
 
 
@@ -600,22 +685,31 @@ int fusd_return(fusd_file_info_t *file, ssize_t retval)
   fusd_msg_t *msg = NULL;
   int fd;
   int driver_retval = 0;
+  int ret;
   struct iovec iov[2];
 
-  if (file == NULL) {
+  if (file == NULL)
+  {
     fprintf(stderr, "fusd_return: NULL file\n");
-    return -EINVAL;
+    ret = -EINVAL;
+    goto exit;
   }
 
+  FILE_LOCK(file);
+
   fd = file->fd;
-  if (!FUSD_FD_VALID(fd)) {
+  if (!FUSD_FD_VALID(fd))
+  {
     fprintf(stderr, "fusd_return: badfd (fd %d)\n", fd);
-    return -EBADF;
+    ret = -EBADF;
+    goto exit_unlock;
   }
 
-  if ((msg = file->fusd_msg) == NULL) {
+  if ((msg = file->fusd_msg) == NULL)
+  {
     fprintf(stderr, "fusd_return: fusd_msg is gone\n");
-    return -EINVAL;
+    ret = -EINVAL;
+    goto exit_unlock;
   }
 
   /* if this was a "DONTREPLY" message, just free the struct */
@@ -623,24 +717,29 @@ int fusd_return(fusd_file_info_t *file, ssize_t retval)
     goto free_memory;
 
   /* do we copy data back to kernel?  how much? */
-  switch(msg->subcmd) {
+  switch(msg->subcmd)
+  {
   case FUSD_READ:
     /* these operations can return data to userspace */
-    if (retval > 0) {
-      msg->datalen = MIN(retval, msg->parm.fops_msg.length);
+    if (retval > 0)
+    {
+      msg->datalen = MIN((int)retval, (int)msg->parm.fops_msg.length);
       retval = msg->datalen;
-    } else {
+    }
+    else
+    {
       msg->datalen = 0;
     }
     break;
+
   case FUSD_IOCTL:
     /* ioctl CAN (in read mode) return data to userspace */
-    if ((retval == 0) && 
-	(_IOC_DIR(msg->parm.fops_msg.cmd) & _IOC_READ))
+    if (/*(retval == 0) && */	(_IOC_DIR(msg->parm.fops_msg.cmd) & _IOC_READ) )
       msg->datalen = _IOC_SIZE(msg->parm.fops_msg.cmd);
     else
       msg->datalen = 0;
     break;
+
   default:
     /* open, close, write, etc. do not return data */
     msg->datalen = 0;
@@ -656,29 +755,35 @@ int fusd_return(fusd_file_info_t *file, ssize_t retval)
   /* pid is NOT copied back. */
 
   /* send message to kernel */
-  if (msg->datalen && msg->data != NULL) {
+  if (msg->datalen && msg->data != NULL)
+  {
     //printf("(msg->datalen [%d] && msg->data != NULL [%p]", msg->datalen, msg->data);
     iov[0].iov_base = msg;
     iov[0].iov_len = sizeof(fusd_msg_t);
     iov[1].iov_base = msg->data;
     iov[1].iov_len = msg->datalen;
-#if 0
     driver_retval = writev(fd, iov, 2);
-#else
-    driver_retval = ioctl(fd, 0xb16b00b5, iov);
-#endif
   }
-  else {
+  else
+  {
     driver_retval = write(fd, msg, sizeof(fusd_msg_t));
   }
 
- free_memory:
+free_memory:
+  FILE_UNLOCK(file);
+
   fusd_destroy(file);
 
+  ret = 0;
   if (driver_retval < 0)
-    return -errno;
-  else
-    return 0;
+    ret = -errno;
+   goto exit;
+
+exit_unlock:
+  FILE_UNLOCK(file);
+
+exit:
+  return ret;
 }
 
 
@@ -690,12 +795,12 @@ char *fusd_unparse_flags(int flags)
   static char ringbuf[RING][5];
   char *s = ringbuf[i];
   i = (i + 1) % RING;
-  
-  sprintf(s, "%c%c%c", 
+
+  sprintf(s, "%c%c%c",
 	  (flags & FUSD_NOTIFY_INPUT)?'R':'-',
 	  (flags & FUSD_NOTIFY_OUTPUT)?'W':'-',
 	  (flags & FUSD_NOTIFY_EXCEPT)?'E':'-');
-  
+
   return s;
 }
 #undef RING