Initial import of character device in userspace support for FreeBSD.

The CUSE library is a wrapper for the devfs kernel functionality which
is exposed through /dev/cuse . In order to function the CUSE kernel
code must either be enabled in the kernel configuration file or loaded
separately as a module. Currently none of the committed items are
connected to the default builds, except for installing the needed
header files. The CUSE code will be connected to the default world and
kernel builds in a follow-up commit.

The CUSE module was written by Hans Petter Selasky, somewhat inspired
by similar functionality found in FUSE. The CUSE library can be used
for many purposes. Currently CUSE is used when running Linux kernel
drivers in user-space, which need to create a character device node to
communicate with its applications. CUSE has full support for almost
all devfs functionality found in the kernel:
 - kevents
 - read
 - write
 - ioctl
 - poll
 - open
 - close
 - mmap
 - private per file handle data

Requested by several people. Also see "multimedia/cuse4bsd-kmod" in
ports.

1 files changed, 800 insertions, 0 deletions

diff --git a/lib/libcuse/cuse_lib.c b/lib/libcuse/cuse_lib.c
new file mode 100644
index 0000000..f518e11
--- /dev/null
+++ b/lib/libcuse/cuse_lib.c
@@ -0,0 +1,800 @@
+/* $FreeBSD$ */
+/*-
+ * Copyright (c) 2010-2012 Hans Petter Selasky. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#include <stdio.h>
+#include <stdint.h>
+#include <pthread.h>
+#include <signal.h>
+#include <unistd.h>
+#include <string.h>
+#include <errno.h>
+#include <stdlib.h>
+#include <stdarg.h>
+
+#include <sys/types.h>
+#include <sys/queue.h>
+#include <sys/fcntl.h>
+#include <sys/mman.h>
+#include <sys/param.h>
+
+#include <fs/cuse/cuse_ioctl.h>
+
+#include "cuse.h"
+
+int	cuse_debug_level;
+
+#ifdef HAVE_DEBUG
+static const char *cuse_cmd_str(int cmd);
+
+#define	DPRINTF(...) do {			\
+	if (cuse_debug_level != 0)		\
+		printf(__VA_ARGS__);		\
+} while (0)
+#else
+#define	DPRINTF(...) do { } while (0)
+#endif
+
+struct cuse_vm_allocation {
+	uint8_t *ptr;
+	uint32_t size;
+};
+
+struct cuse_dev_entered {
+	TAILQ_ENTRY(cuse_dev_entered) entry;
+	pthread_t thread;
+	void   *per_file_handle;
+	struct cuse_dev *cdev;
+	int	cmd;
+	int	is_local;
+	int	got_signal;
+};
+
+struct cuse_dev {
+	TAILQ_ENTRY(cuse_dev) entry;
+	const struct cuse_methods *mtod;
+	void   *priv0;
+	void   *priv1;
+};
+
+static TAILQ_HEAD(, cuse_dev) h_cuse;
+static TAILQ_HEAD(, cuse_dev_entered) h_cuse_entered;
+static int f_cuse = -1;
+static pthread_mutex_t m_cuse;
+static struct cuse_vm_allocation a_cuse[CUSE_ALLOC_UNIT_MAX];
+
+static void
+cuse_lock(void)
+{
+	pthread_mutex_lock(&m_cuse);
+}
+
+static void
+cuse_unlock(void)
+{
+	pthread_mutex_unlock(&m_cuse);
+}
+
+int
+cuse_init(void)
+{
+	pthread_mutexattr_t attr;
+
+	f_cuse = open("/dev/cuse", O_RDWR);
+	if (f_cuse < 0) {
+		if (feature_present("cuse") == 0)
+			return (CUSE_ERR_NOT_LOADED);
+		else
+			return (CUSE_ERR_INVALID);
+	}
+	pthread_mutexattr_init(&attr);
+	pthread_mutexattr_settype(&attr, PTHREAD_MUTEX_RECURSIVE);
+	pthread_mutex_init(&m_cuse, &attr);
+
+	TAILQ_INIT(&h_cuse);
+	TAILQ_INIT(&h_cuse_entered);
+
+	return (0);
+}
+
+int
+cuse_uninit(void)
+{
+	int f;
+
+	if (f_cuse < 0)
+		return (CUSE_ERR_INVALID);
+
+	f = f_cuse;
+	f_cuse = -1;
+
+	close(f);
+
+	pthread_mutex_destroy(&m_cuse);
+
+	memset(a_cuse, 0, sizeof(a_cuse));
+
+	return (0);
+}
+
+unsigned long
+cuse_vmoffset(void *_ptr)
+{
+	uint8_t *ptr_min;
+	uint8_t *ptr_max;
+	uint8_t *ptr = _ptr;
+	unsigned long remainder;
+	int n;
+
+	cuse_lock();
+	for (n = 0; n != CUSE_ALLOC_UNIT_MAX; n++) {
+		if (a_cuse[n].ptr == NULL)
+			continue;
+
+		ptr_min = a_cuse[n].ptr;
+		ptr_max = a_cuse[n].ptr + a_cuse[n].size - 1;
+
+		if ((ptr >= ptr_min) && (ptr <= ptr_max)) {
+
+			cuse_unlock();
+
+			remainder = (ptr - ptr_min);
+
+			remainder -= remainder % PAGE_SIZE;
+
+			return ((n * PAGE_SIZE * CUSE_ALLOC_PAGES_MAX) + remainder);
+		}
+	}
+	cuse_unlock();
+
+	return (0x80000000UL);		/* failure */
+}
+
+void   *
+cuse_vmalloc(int size)
+{
+	struct cuse_alloc_info info;
+	void *ptr;
+	int error;
+	int n;
+
+	if (f_cuse < 0)
+		return (NULL);
+
+	memset(&info, 0, sizeof(info));
+
+	if (size < 1)
+		return (NULL);
+
+	info.page_count = (size + PAGE_SIZE - 1) / PAGE_SIZE;
+
+	cuse_lock();
+	for (n = 0; n != CUSE_ALLOC_UNIT_MAX; n++) {
+
+		if (a_cuse[n].ptr != NULL)
+			continue;
+
+		a_cuse[n].ptr = ((uint8_t *)1);	/* reserve */
+		a_cuse[n].size = 0;
+
+		cuse_unlock();
+
+		info.alloc_nr = n;
+
+		error = ioctl(f_cuse, CUSE_IOCTL_ALLOC_MEMORY, &info);
+
+		if (error) {
+
+			cuse_lock();
+
+			a_cuse[n].ptr = NULL;
+
+			if (errno == EBUSY)
+				continue;
+			else
+				break;
+		}
+		ptr = mmap(NULL, info.page_count * PAGE_SIZE,
+		    PROT_READ | PROT_WRITE,
+		    MAP_SHARED, f_cuse, CUSE_ALLOC_PAGES_MAX *
+		    PAGE_SIZE * n);
+
+		if (ptr == MAP_FAILED) {
+
+			error = ioctl(f_cuse, CUSE_IOCTL_FREE_MEMORY, &info);
+
+			if (error) {
+				/* ignore */
+			}
+			cuse_lock();
+
+			a_cuse[n].ptr = NULL;
+
+			break;
+		}
+		cuse_lock();
+		a_cuse[n].ptr = ptr;
+		a_cuse[n].size = size;
+		cuse_unlock();
+
+		return (ptr);		/* success */
+	}
+	cuse_unlock();
+	return (NULL);			/* failure */
+}
+
+int
+cuse_is_vmalloc_addr(void *ptr)
+{
+	int n;
+
+	if (f_cuse < 0 || ptr == NULL)
+		return (0);		/* false */
+
+	cuse_lock();
+	for (n = 0; n != CUSE_ALLOC_UNIT_MAX; n++) {
+		if (a_cuse[n].ptr == ptr)
+			break;
+	}
+	cuse_unlock();
+
+	return (n != CUSE_ALLOC_UNIT_MAX);
+}
+
+void
+cuse_vmfree(void *ptr)
+{
+	struct cuse_alloc_info info;
+	int error;
+	int n;
+
+	if (f_cuse < 0)
+		return;
+
+	memset(&info, 0, sizeof(info));
+
+	cuse_lock();
+	for (n = 0; n != CUSE_ALLOC_UNIT_MAX; n++) {
+		if (a_cuse[n].ptr != ptr)
+			continue;
+
+		cuse_unlock();
+
+		info.alloc_nr = n;
+
+		munmap(ptr, a_cuse[n].size);
+
+		error = ioctl(f_cuse, CUSE_IOCTL_FREE_MEMORY, &info);
+
+		if (error) {
+			/* ignore */
+		}
+		cuse_lock();
+
+		a_cuse[n].ptr = NULL;
+		a_cuse[n].size = 0;
+
+		break;
+	}
+	cuse_unlock();
+}
+
+int
+cuse_alloc_unit_number_by_id(int *pnum, int id)
+{
+	int error;
+
+	if (f_cuse < 0)
+		return (CUSE_ERR_INVALID);
+
+	*pnum = (id & CUSE_ID_MASK);
+
+	error = ioctl(f_cuse, CUSE_IOCTL_ALLOC_UNIT_BY_ID, pnum);
+	if (error)
+		return (CUSE_ERR_NO_MEMORY);
+
+	return (0);
+
+}
+
+int
+cuse_free_unit_number_by_id(int num, int id)
+{
+	int error;
+
+	if (f_cuse < 0)
+		return (CUSE_ERR_INVALID);
+
+	if (num != -1 || id != -1)
+		num = (id & CUSE_ID_MASK) | (num & 0xFF);
+
+	error = ioctl(f_cuse, CUSE_IOCTL_FREE_UNIT_BY_ID, &num);
+	if (error)
+		return (CUSE_ERR_NO_MEMORY);
+
+	return (0);
+}
+
+int
+cuse_alloc_unit_number(int *pnum)
+{
+	int error;
+
+	if (f_cuse < 0)
+		return (CUSE_ERR_INVALID);
+
+	error = ioctl(f_cuse, CUSE_IOCTL_ALLOC_UNIT, pnum);
+	if (error)
+		return (CUSE_ERR_NO_MEMORY);
+
+	return (0);
+}
+
+int
+cuse_free_unit_number(int num)
+{
+	int error;
+
+	if (f_cuse < 0)
+		return (CUSE_ERR_INVALID);
+
+	error = ioctl(f_cuse, CUSE_IOCTL_FREE_UNIT, &num);
+	if (error)
+		return (CUSE_ERR_NO_MEMORY);
+
+	return (0);
+}
+
+struct cuse_dev *
+cuse_dev_create(const struct cuse_methods *mtod, void *priv0, void *priv1,
+    uid_t _uid, gid_t _gid, int _perms, const char *_fmt,...)
+{
+	struct cuse_create_dev info;
+	struct cuse_dev *cdev;
+	va_list args;
+	int error;
+
+	if (f_cuse < 0)
+		return (NULL);
+
+	cdev = malloc(sizeof(*cdev));
+	if (cdev == NULL)
+		return (NULL);
+
+	memset(cdev, 0, sizeof(*cdev));
+
+	cdev->mtod = mtod;
+	cdev->priv0 = priv0;
+	cdev->priv1 = priv1;
+
+	memset(&info, 0, sizeof(info));
+
+	info.dev = cdev;
+	info.user_id = _uid;
+	info.group_id = _gid;
+	info.permissions = _perms;
+
+	va_start(args, _fmt);
+	vsnprintf(info.devname, sizeof(info.devname), _fmt, args);
+	va_end(args);
+
+	error = ioctl(f_cuse, CUSE_IOCTL_CREATE_DEV, &info);
+	if (error) {
+		free(cdev);
+		return (NULL);
+	}
+	cuse_lock();
+	TAILQ_INSERT_TAIL(&h_cuse, cdev, entry);
+	cuse_unlock();
+
+	return (cdev);
+}
+
+
+void
+cuse_dev_destroy(struct cuse_dev *cdev)
+{
+	int error;
+
+	if (f_cuse < 0)
+		return;
+
+	cuse_lock();
+	TAILQ_REMOVE(&h_cuse, cdev, entry);
+	cuse_unlock();
+
+	error = ioctl(f_cuse, CUSE_IOCTL_DESTROY_DEV, cdev);
+	if (error)
+		return;
+
+	free(cdev);
+}
+
+void   *
+cuse_dev_get_priv0(struct cuse_dev *cdev)
+{
+	return (cdev->priv0);
+}
+
+void   *
+cuse_dev_get_priv1(struct cuse_dev *cdev)
+{
+	return (cdev->priv1);
+}
+
+void
+cuse_dev_set_priv0(struct cuse_dev *cdev, void *priv)
+{
+	cdev->priv0 = priv;
+}
+
+void
+cuse_dev_set_priv1(struct cuse_dev *cdev, void *priv)
+{
+	cdev->priv1 = priv;
+}
+
+int
+cuse_wait_and_process(void)
+{
+	pthread_t curr = pthread_self();
+	struct cuse_dev_entered *pe;
+	struct cuse_dev_entered enter;
+	struct cuse_command info;
+	struct cuse_dev *cdev;
+	int error;
+
+	if (f_cuse < 0)
+		return (CUSE_ERR_INVALID);
+
+	error = ioctl(f_cuse, CUSE_IOCTL_GET_COMMAND, &info);
+	if (error)
+		return (CUSE_ERR_OTHER);
+
+	cdev = info.dev;
+
+	cuse_lock();
+	enter.thread = curr;
+	enter.per_file_handle = (void *)info.per_file_handle;
+	enter.cmd = info.command;
+	enter.is_local = 0;
+	enter.got_signal = 0;
+	enter.cdev = cdev;
+	TAILQ_INSERT_TAIL(&h_cuse_entered, &enter, entry);
+	cuse_unlock();
+
+	DPRINTF("cuse: Command = %d = %s, flags = %d, arg = 0x%08x, ptr = 0x%08x\n",
+	    (int)info.command, cuse_cmd_str(info.command), (int)info.fflags,
+	    (int)info.argument, (int)info.data_pointer);
+
+	switch (info.command) {
+	case CUSE_CMD_OPEN:
+		if (cdev->mtod->cm_open != NULL)
+			error = (cdev->mtod->cm_open) (cdev, (int)info.fflags);
+		else
+			error = 0;
+		break;
+
+	case CUSE_CMD_CLOSE:
+
+		/* wait for other threads to stop */
+
+		while (1) {
+
+			error = 0;
+
+			cuse_lock();
+			TAILQ_FOREACH(pe, &h_cuse_entered, entry) {
+				if (pe->cdev != cdev)
+					continue;
+				if (pe->thread == curr)
+					continue;
+				if (pe->per_file_handle !=
+				    enter.per_file_handle)
+					continue;
+				pe->got_signal = 1;
+				pthread_kill(pe->thread, SIGHUP);
+				error = CUSE_ERR_BUSY;
+			}
+			cuse_unlock();
+
+			if (error == 0)
+				break;
+			else
+				usleep(10000);
+		}
+
+		if (cdev->mtod->cm_close != NULL)
+			error = (cdev->mtod->cm_close) (cdev, (int)info.fflags);
+		else
+			error = 0;
+		break;
+
+	case CUSE_CMD_READ:
+		if (cdev->mtod->cm_read != NULL) {
+			error = (cdev->mtod->cm_read) (cdev, (int)info.fflags,
+			    (void *)info.data_pointer, (int)info.argument);
+		} else {
+			error = CUSE_ERR_INVALID;
+		}
+		break;
+
+	case CUSE_CMD_WRITE:
+		if (cdev->mtod->cm_write != NULL) {
+			error = (cdev->mtod->cm_write) (cdev, (int)info.fflags,
+			    (void *)info.data_pointer, (int)info.argument);
+		} else {
+			error = CUSE_ERR_INVALID;
+		}
+		break;
+
+	case CUSE_CMD_IOCTL:
+		if (cdev->mtod->cm_ioctl != NULL) {
+			error = (cdev->mtod->cm_ioctl) (cdev, (int)info.fflags,
+			    (unsigned int)info.argument, (void *)info.data_pointer);
+		} else {
+			error = CUSE_ERR_INVALID;
+		}
+		break;
+
+	case CUSE_CMD_POLL:
+		if (cdev->mtod->cm_poll != NULL) {
+			error = (cdev->mtod->cm_poll) (cdev, (int)info.fflags,
+			    (int)info.argument);
+		} else {
+			error = CUSE_POLL_ERROR;
+		}
+		break;
+
+	case CUSE_CMD_SIGNAL:
+		cuse_lock();
+		TAILQ_FOREACH(pe, &h_cuse_entered, entry) {
+			if (pe->cdev != cdev)
+				continue;
+			if (pe->thread == curr)
+				continue;
+			if (pe->per_file_handle !=
+			    enter.per_file_handle)
+				continue;
+			pe->got_signal = 1;
+			pthread_kill(pe->thread, SIGHUP);
+		}
+		cuse_unlock();
+		break;
+
+	default:
+		error = CUSE_ERR_INVALID;
+		break;
+	}
+
+	DPRINTF("cuse: Command error = %d for %s\n",
+	    error, cuse_cmd_str(info.command));
+
+	cuse_lock();
+	TAILQ_REMOVE(&h_cuse_entered, &enter, entry);
+	cuse_unlock();
+
+	/* we ignore any sync command failures */
+	ioctl(f_cuse, CUSE_IOCTL_SYNC_COMMAND, &error);
+
+	return (0);
+}
+
+static struct cuse_dev_entered *
+cuse_dev_get_entered(void)
+{
+	struct cuse_dev_entered *pe;
+	pthread_t curr = pthread_self();
+
+	cuse_lock();
+	TAILQ_FOREACH(pe, &h_cuse_entered, entry) {
+		if (pe->thread == curr)
+			break;
+	}
+	cuse_unlock();
+	return (pe);
+}
+
+void
+cuse_dev_set_per_file_handle(struct cuse_dev *cdev, void *handle)
+{
+	struct cuse_dev_entered *pe;
+
+	pe = cuse_dev_get_entered();
+	if (pe == NULL || pe->cdev != cdev)
+		return;
+
+	pe->per_file_handle = handle;
+	ioctl(f_cuse, CUSE_IOCTL_SET_PFH, &handle);
+}
+
+void   *
+cuse_dev_get_per_file_handle(struct cuse_dev *cdev)
+{
+	struct cuse_dev_entered *pe;
+
+	pe = cuse_dev_get_entered();
+	if (pe == NULL || pe->cdev != cdev)
+		return (NULL);
+
+	return (pe->per_file_handle);
+}
+
+void
+cuse_set_local(int val)
+{
+	struct cuse_dev_entered *pe;
+
+	pe = cuse_dev_get_entered();
+	if (pe == NULL)
+		return;
+
+	pe->is_local = val;
+}
+
+#ifdef HAVE_DEBUG
+static const char *
+cuse_cmd_str(int cmd)
+{
+	static const char *str[CUSE_CMD_MAX] = {
+		[CUSE_CMD_NONE] = "none",
+		[CUSE_CMD_OPEN] = "open",
+		[CUSE_CMD_CLOSE] = "close",
+		[CUSE_CMD_READ] = "read",
+		[CUSE_CMD_WRITE] = "write",
+		[CUSE_CMD_IOCTL] = "ioctl",
+		[CUSE_CMD_POLL] = "poll",
+		[CUSE_CMD_SIGNAL] = "signal",
+		[CUSE_CMD_SYNC] = "sync",
+	};
+
+	if ((cmd >= 0) && (cmd < CUSE_CMD_MAX) &&
+	    (str[cmd] != NULL))
+		return (str[cmd]);
+	else
+		return ("unknown");
+}
+
+#endif
+
+int
+cuse_get_local(void)
+{
+	struct cuse_dev_entered *pe;
+
+	pe = cuse_dev_get_entered();
+	if (pe == NULL)
+		return (0);
+
+	return (pe->is_local);
+}
+
+int
+cuse_copy_out(const void *src, void *user_dst, int len)
+{
+	struct cuse_data_chunk info;
+	struct cuse_dev_entered *pe;
+	int error;
+
+	if ((f_cuse < 0) || (len < 0))
+		return (CUSE_ERR_INVALID);
+
+	pe = cuse_dev_get_entered();
+	if (pe == NULL)
+		return (CUSE_ERR_INVALID);
+
+	DPRINTF("cuse: copy_out(%p,%p,%d), cmd = %d = %s\n",
+	    src, user_dst, len, pe->cmd, cuse_cmd_str(pe->cmd));
+
+	if (pe->is_local) {
+		memcpy(user_dst, src, len);
+	} else {
+		info.local_ptr = (unsigned long)src;
+		info.peer_ptr = (unsigned long)user_dst;
+		info.length = len;
+
+		error = ioctl(f_cuse, CUSE_IOCTL_WRITE_DATA, &info);
+		if (error) {
+			DPRINTF("cuse: copy_out() error = %d\n", errno);
+			return (CUSE_ERR_FAULT);
+		}
+	}
+	return (0);
+}
+
+int
+cuse_copy_in(const void *user_src, void *dst, int len)
+{
+	struct cuse_data_chunk info;
+	struct cuse_dev_entered *pe;
+	int error;
+
+	if ((f_cuse < 0) || (len < 0))
+		return (CUSE_ERR_INVALID);
+
+	pe = cuse_dev_get_entered();
+	if (pe == NULL)
+		return (CUSE_ERR_INVALID);
+
+	DPRINTF("cuse: copy_in(%p,%p,%d), cmd = %d = %s\n",
+	    user_src, dst, len, pe->cmd, cuse_cmd_str(pe->cmd));
+
+	if (pe->is_local) {
+		memcpy(dst, user_src, len);
+	} else {
+		info.local_ptr = (unsigned long)dst;
+		info.peer_ptr = (unsigned long)user_src;
+		info.length = len;
+
+		error = ioctl(f_cuse, CUSE_IOCTL_READ_DATA, &info);
+		if (error) {
+			DPRINTF("cuse: copy_in() error = %d\n", errno);
+			return (CUSE_ERR_FAULT);
+		}
+	}
+	return (0);
+}
+
+struct cuse_dev *
+cuse_dev_get_current(int *pcmd)
+{
+	struct cuse_dev_entered *pe;
+
+	pe = cuse_dev_get_entered();
+	if (pe == NULL) {
+		if (pcmd != NULL)
+			*pcmd = 0;
+		return (NULL);
+	}
+	if (pcmd != NULL)
+		*pcmd = pe->cmd;
+	return (pe->cdev);
+}
+
+int
+cuse_got_peer_signal(void)
+{
+	struct cuse_dev_entered *pe;
+
+	pe = cuse_dev_get_entered();
+	if (pe == NULL)
+		return (CUSE_ERR_INVALID);
+
+	if (pe->got_signal)
+		return (0);
+
+	return (CUSE_ERR_OTHER);
+}
+
+void
+cuse_poll_wakeup(void)
+{
+	int error = 0;
+
+	if (f_cuse < 0)
+		return;
+
+	ioctl(f_cuse, CUSE_IOCTL_SELWAKEUP, &error);
+}