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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [Minios-devel] [UNIKRAFT PATCH 1/6] lib/devfs: Initial import from OSv
commit: c8395118cb580f2395cac6c53999feb217fd2c2f
Signed-off-by: Vlad-Andrei Badoiu <vlad_andrei.badoiu@xxxxxxxxxxxxxxx>
---
lib/Config.uk | 1 +
lib/Makefile.uk | 1 +
lib/devfs/Config.uk | 4 +
lib/devfs/Makefile.uk | 4 +
lib/devfs/devfs.h | 37 +++
lib/devfs/devfs_vnops.c | 284 +++++++++++++++++++++
lib/devfs/device.c | 537 ++++++++++++++++++++++++++++++++++++++++
7 files changed, 868 insertions(+)
create mode 100644 lib/devfs/Config.uk
create mode 100644 lib/devfs/Makefile.uk
create mode 100644 lib/devfs/devfs.h
create mode 100644 lib/devfs/devfs_vnops.c
create mode 100644 lib/devfs/device.c
diff --git a/lib/Config.uk b/lib/Config.uk
index 553d4c6b..ea8b06a3 100644
--- a/lib/Config.uk
+++ b/lib/Config.uk
@@ -40,6 +40,7 @@ source "lib/ukschedcoop/Config.uk"
source "lib/fdt/Config.uk"
source "lib/vfscore/Config.uk"
source "lib/ramfs/Config.uk"
+source "lib/devfs/Config.uk"
source "lib/uklock/Config.uk"
source "lib/ukmpi/Config.uk"
source "lib/ukswrand/Config.uk"
diff --git a/lib/Makefile.uk b/lib/Makefile.uk
index 54a957de..97fdf7b2 100644
--- a/lib/Makefile.uk
+++ b/lib/Makefile.uk
@@ -18,6 +18,7 @@ $(eval $(call _import_lib,$(CONFIG_UK_BASE)/lib/ukschedcoop))
$(eval $(call _import_lib,$(CONFIG_UK_BASE)/lib/fdt))
$(eval $(call _import_lib,$(CONFIG_UK_BASE)/lib/vfscore))
$(eval $(call _import_lib,$(CONFIG_UK_BASE)/lib/ramfs))
+$(eval $(call _import_lib,$(CONFIG_UK_BASE)/lib/devfs))
$(eval $(call _import_lib,$(CONFIG_UK_BASE)/lib/uklock))
$(eval $(call _import_lib,$(CONFIG_UK_BASE)/lib/ukmpi))
$(eval $(call _import_lib,$(CONFIG_UK_BASE)/lib/ukbus))
diff --git a/lib/devfs/Config.uk b/lib/devfs/Config.uk
new file mode 100644
index 00000000..9ad502f7
--- /dev/null
+++ b/lib/devfs/Config.uk
@@ -0,0 +1,4 @@
+config LIBDEVFS
+ bool "devfs: devfs file system"
+ default n
+ depends on LIBVFSCORE
diff --git a/lib/devfs/Makefile.uk b/lib/devfs/Makefile.uk
new file mode 100644
index 00000000..f33187f3
--- /dev/null
+++ b/lib/devfs/Makefile.uk
@@ -0,0 +1,4 @@
+$(eval $(call addlib_s,libdevfs,$(CONFIG_LIBDEVFS)))
+
+LIBDEVFS_SRCS-y += $(LIBDEVFS_BASE)/device.c
+LIBDEVFS_SRCS-y += $(LIBDEVFS_BASE)/devfs_vnops.c
diff --git a/lib/devfs/devfs.h b/lib/devfs/devfs.h
new file mode 100644
index 00000000..bdf50609
--- /dev/null
+++ b/lib/devfs/devfs.h
@@ -0,0 +1,37 @@
+/*
+ * Copyright (c) 2007, Kohsuke Ohtani
+ * 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.
+ * 3. Neither the name of the author nor the names of any co-contributors
+ * may be used to endorse or promote products derived from this software
+ * without specific prior written permission.
+ *
+ * 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.
+ */
+
+#ifndef _DEVFS_H
+#define _DEVFS_H
+
+#include <assert.h>
+
+/* #define DEBUG_DEVFS 1 */
+
+#endif /* !_DEVFS_H */
diff --git a/lib/devfs/devfs_vnops.c b/lib/devfs/devfs_vnops.c
new file mode 100644
index 00000000..1e69e4a6
--- /dev/null
+++ b/lib/devfs/devfs_vnops.c
@@ -0,0 +1,284 @@
+/*
+ * Copyright (c) 2005-2007, Kohsuke Ohtani
+ * 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.
+ * 3. Neither the name of the author nor the names of any co-contributors
+ * may be used to endorse or promote products derived from this software
+ * without specific prior written permission.
+ *
+ * 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.
+ */
+
+/*
+ * devfs - device file system.
+ */
+
+#include <sys/stat.h>
+
+#include <ctype.h>
+#include <unistd.h>
+#include <errno.h>
+#include <string.h>
+#include <stdlib.h>
+#include <limits.h>
+#include <fcntl.h>
+#include <stdio.h>
+
+#include <osv/prex.h>
+#include <osv/device.h>
+#include <osv/vnode.h>
+#include <osv/mount.h>
+#include <osv/dentry.h>
+
+#include "devfs.h"
+
+#ifdef DEBUG_DEVFS
+#define DPRINTF(a) dprintf a
+#else
+#define DPRINTF(a) do {} while (0)
+#endif
+
+#define ASSERT(e) assert(e)
+
+static uint64_t inode_count = 1; /* inode 0 is reserved to root */
+
+static int
+devfs_open(struct file *fp)
+{
+ struct vnode *vp = fp->f_dentry->d_vnode;
+ char *path = fp->f_dentry->d_path;
+ struct device *dev;
+ int error;
+
+ DPRINTF(("devfs_open: path=%s\n", path));
+
+ if (!strcmp(path, "/")) /* root ? */
+ return 0;
+
+ if (vp->v_flags & VPROTDEV) {
+ DPRINTF(("devfs_open: failed to open protected device.\n"));
+ return EPERM;
+ }
+ if (*path == '/')
+ path++;
+ error = device_open(path, fp->f_flags & DO_RWMASK, &dev);
+ if (error) {
+ DPRINTF(("devfs_open: can not open device = %s error=%d\n",
+ path, error));
+ return error;
+ }
+ vp->v_data = (void *)dev; /* Store private data */
+ return 0;
+}
+
+static int
+devfs_close(struct vnode *vp, struct file *fp)
+{
+
+ DPRINTF(("devfs_close: fp=%x\n", fp));
+
+ if (!strcmp(fp->f_dentry->d_path, "/")) /* root ? */
+ return 0;
+
+ return device_close((device*)vp->v_data);
+}
+
+static int
+devfs_read(struct vnode *vp, struct file *fp, struct uio *uio, int ioflags)
+{
+ return device_read((device*)vp->v_data, uio, ioflags);
+}
+
+static int
+devfs_write(struct vnode *vp, struct uio *uio, int ioflags)
+{
+ return device_write((device*)vp->v_data, uio, ioflags);
+}
+
+static int
+devfs_ioctl(struct vnode *vp, struct file *fp, u_long cmd, void *arg)
+{
+ int error;
+
+ error = device_ioctl((device*)vp->v_data, cmd, arg);
+ DPRINTF(("devfs_ioctl: cmd=%x\n", cmd));
+ return error;
+}
+
+static int
+devfs_lookup(struct vnode *dvp, char *name, struct vnode **vpp)
+{
+ struct devinfo info;
+ struct vnode *vp;
+ int error, i;
+
+ DPRINTF(("devfs_lookup:%s\n", name));
+
+ *vpp = NULL;
+
+ if (*name == '\0')
+ return ENOENT;
+
+ i = 0;
+ error = 0;
+ info.cookie = 0;
+ for (;;) {
+ error = device_info(&info);
+ if (error) {
+ return ENOENT;
+ }
+ if (!strncmp(info.name, name, MAXDEVNAME))
+ break;
+ i++;
+ }
+ if (vget(dvp->v_mount, inode_count++, &vp)) {
+ /* found in cache */
+ *vpp = vp;
+ return 0;
+ }
+ if (!vp)
+ return ENOMEM;
+ vp->v_type = (info.flags & D_CHR) ? VCHR : VBLK;
+ if (info.flags & D_TTY)
+ vp->v_flags |= VISTTY;
+
+ vp->v_mode = (mode_t)(S_IRUSR | S_IWUSR);
+
+ *vpp = vp;
+
+ return 0;
+}
+
+/*
+ * @vp: vnode of the directory.
+ */
+static int
+devfs_readdir(struct vnode *vp, struct file *fp, struct dirent *dir)
+{
+ struct devinfo info;
+ int error, i;
+
+ DPRINTF(("devfs_readdir offset=%d\n", fp->f_offset));
+
+ i = 0;
+ error = 0;
+ info.cookie = 0;
+ do {
+ error = device_info(&info);
+ if (error)
+ return ENOENT;
+ } while (i++ != fp->f_offset);
+
+ dir->d_type = 0;
+ if (info.flags & D_CHR)
+ dir->d_type = DT_CHR;
+ else if (info.flags & D_BLK)
+ dir->d_type = DT_BLK;
+ strlcpy((char *)&dir->d_name, info.name, sizeof(dir->d_name));
+ dir->d_fileno = fp->f_offset;
+// dir->d_namlen = strlen(dir->d_name);
+
+ DPRINTF(("devfs_readdir: %s\n", dir->d_name));
+ fp->f_offset++;
+ return 0;
+}
+
+static int
+devfs_unmount(struct mount *mp, int flags)
+{
+ release_mp_dentries(mp);
+ return 0;
+}
+
+int
+devfs_init(void)
+{
+ return 0;
+}
+
+static int
+devfs_getattr(struct vnode *vnode, struct vattr *attr)
+{
+ attr->va_nodeid = vnode->v_ino;
+ attr->va_size = vnode->v_size;
+ return 0;
+}
+
+#define devfs_mount ((vfsop_mount_t)vfs_nullop)
+#define devfs_sync ((vfsop_sync_t)vfs_nullop)
+#define devfs_vget ((vfsop_vget_t)vfs_nullop)
+#define devfs_statfs ((vfsop_statfs_t)vfs_nullop)
+
+#define devfs_seek ((vnop_seek_t)vop_nullop)
+#define devfs_fsync ((vnop_fsync_t)vop_nullop)
+#define devfs_create ((vnop_create_t)vop_einval)
+#define devfs_remove ((vnop_remove_t)vop_einval)
+#define devfs_rename ((vnop_rename_t)vop_einval)
+#define devfs_mkdir ((vnop_mkdir_t)vop_einval)
+#define devfs_rmdir ((vnop_rmdir_t)vop_einval)
+#define devfs_setattr ((vnop_setattr_t)vop_eperm)
+#define devfs_inactive ((vnop_inactive_t)vop_nullop)
+#define devfs_truncate ((vnop_truncate_t)vop_nullop)
+#define devfs_link ((vnop_link_t)vop_eperm)
+#define devfs_fallocate ((vnop_fallocate_t)vop_nullop)
+#define devfs_readlink ((vnop_readlink_t)vop_nullop)
+#define devfs_symlink ((vnop_symlink_t)vop_nullop)
+
+/*
+ * vnode operations
+ */
+struct vnops devfs_vnops = {
+ devfs_open, /* open */
+ devfs_close, /* close */
+ devfs_read, /* read */
+ devfs_write, /* write */
+ devfs_seek, /* seek */
+ devfs_ioctl, /* ioctl */
+ devfs_fsync, /* fsync */
+ devfs_readdir, /* readdir */
+ devfs_lookup, /* lookup */
+ devfs_create, /* create */
+ devfs_remove, /* remove */
+ devfs_rename, /* remame */
+ devfs_mkdir, /* mkdir */
+ devfs_rmdir, /* rmdir */
+ devfs_getattr, /* getattr */
+ devfs_setattr, /* setattr */
+ devfs_inactive, /* inactive */
+ devfs_truncate, /* truncate */
+ devfs_link, /* link */
+ (vnop_cache_t) nullptr, /* arc */
+ devfs_fallocate, /* fallocate */
+ devfs_readlink, /* read link */
+ devfs_symlink, /* symbolic link */
+};
+
+/*
+ * File system operations
+ */
+struct vfsops devfs_vfsops = {
+ devfs_mount, /* mount */
+ devfs_unmount, /* unmount */
+ devfs_sync, /* sync */
+ devfs_vget, /* vget */
+ devfs_statfs, /* statfs */
+ &devfs_vnops, /* vnops */
+};
diff --git a/lib/devfs/device.c b/lib/devfs/device.c
new file mode 100644
index 00000000..a0cd9768
--- /dev/null
+++ b/lib/devfs/device.c
@@ -0,0 +1,537 @@
+/*-
+ * Copyright (c) 2005-2009, Kohsuke Ohtani
+ * 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.
+ * 3. Neither the name of the author nor the names of any co-contributors
+ * may be used to endorse or promote products derived from this software
+ * without specific prior written permission.
+ *
+ * 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.
+ */
+
+/*
+ * device.c - device I/O support routines
+ */
+
+/**
+ * The device_* system calls are interfaces to access the specific
+ * device object which is handled by the related device driver.
+ *
+ * The routines in this moduile have the following role:
+ * - Manage the name space for device objects.
+ * - Forward user I/O requests to the drivers with minimum check.
+ * - Provide the table for the Driver-Kernel Interface.
+ */
+
+#include <stdlib.h>
+#include <stdio.h>
+#include <unistd.h>
+#include <errno.h>
+#include <assert.h>
+#include <string.h>
+
+#include <osv/prex.h>
+#include <osv/mutex.h>
+#include <osv/device.h>
+#include <osv/debug.h>
+#include <osv/buf.h>
+
+#include <geom/geom_disk.h>
+
+mutex sched_mutex;
+#define sched_lock() sched_mutex.lock()
+#define sched_unlock() sched_mutex.unlock()
+
+
+/* list head of the devices */
+static struct device *device_list = NULL;
+
+/*
+ * Look up a device object by device name.
+ */
+static struct device *
+device_lookup(const char *name)
+{
+ struct device *dev;
+
+ for (dev = device_list; dev != NULL; dev = dev->next) {
+ if (!strncmp(dev->name, name, MAXDEVNAME))
+ return dev;
+ }
+ return NULL;
+}
+
+struct partition_table_entry {
+ uint8_t bootable;
+ uint8_t starting_head;
+ uint16_t starting_sector:6;
+ uint16_t starting_cylinder:10;
+ uint8_t system_id;
+ uint8_t ending_head;
+ uint16_t ending_sector:6;
+ uint16_t ending_cylinder:10;
+ uint32_t rela_sector;
+ uint32_t total_sectors;
+} __attribute__((packed));
+
+/*
+ * read_partition_table - given a device @dev, create one subdevice per
partition
+ * found in that device.
+ *
+ * This function will read a partition table from the canonical location of the
+ * device pointed by @dev. For each partition found, a new device will be
+ * created. The newly created device will have most of its data copied from
+ * @dev, except for its name, offset and size.
+ */
+void read_partition_table(struct device *dev)
+{
+ struct buf *bp;
+ unsigned long offset;
+ int index;
+
+ if (bread(dev, 0, &bp) != 0) {
+ debugf("read_partition_table failed for %s\n", dev->name);
+ return;
+ }
+
+ sched_lock();
+ // A real partition table (MBR) ends in the two bytes 0x55, 0xAA (see
+ // arch/x64/boot16.S on where we put those on the OSv image). If we
+ // don't find those, this is an unpartitioned disk.
+ if (((unsigned char*)bp->b_data)[510] == 0x55 &&
+ ((unsigned char*)bp->b_data)[511] == 0xAA)
+ for (offset = 0x1be, index = 0; offset < 0x1fe; offset += 0x10,
index++) {
+ char dev_name[MAXDEVNAME];
+ struct device *new_dev;
+
+ auto* entry = static_cast<struct
partition_table_entry*>(bp->b_data + offset);
+
+ if (entry->system_id == 0) {
+ continue;
+ }
+
+ if (entry->starting_sector == 0) {
+ continue;
+ }
+
+ snprintf(dev_name, MAXDEVNAME, "%s.%d", dev->name, index);
+ new_dev = device_create(dev->driver, dev_name, dev->flags);
+ free(new_dev->private_data);
+
+ new_dev->offset = (off_t)entry->rela_sector << 9;
+ new_dev->size = (off_t)entry->total_sectors << 9;
+ new_dev->max_io_size = dev->max_io_size;
+ new_dev->private_data = dev->private_data;
+ device_set_softc(new_dev, device_get_softc(dev));
+ }
+
+ sched_unlock();
+ brelse(bp);
+}
+
+void device_register(struct device *dev, const char *name, int flags)
+{
+ size_t len;
+ void *priv = NULL;
+
+ assert(dev->driver != NULL);
+
+ /* Check the length of name. */
+ len = strnlen(name, MAXDEVNAME);
+ if (len == 0 || len >= MAXDEVNAME)
+ return;
+
+ sched_lock();
+
+ /* Check if specified name is already used. */
+ if (device_lookup(name) != NULL)
+ sys_panic("duplicate device");
+
+ /*
+ * Allocate a device and device private data.
+ */
+ if (dev->driver->devsz != 0) {
+ if ((priv = malloc(dev->driver->devsz)) == NULL)
+ sys_panic("devsz");
+ memset(priv, 0, dev->driver->devsz);
+ }
+
+ strlcpy(dev->name, name, len + 1);
+ dev->flags = flags;
+ dev->active = 1;
+ dev->refcnt = 1;
+ dev->offset = 0;
+ dev->private_data = priv;
+ dev->next = device_list;
+ dev->max_io_size = UINT_MAX;
+ device_list = dev;
+
+ sched_unlock();
+}
+
+
+/*
+ * device_create - create new device object.
+ *
+ * A device object is created by the device driver to provide
+ * I/O services to applications. Returns device ID on
+ * success, or 0 on failure.
+ */
+struct device *
+device_create(struct driver *drv, const char *name, int flags)
+{
+ struct device *dev;
+ size_t len;
+
+ assert(drv != NULL);
+
+ /* Check the length of name. */
+ len = strnlen(name, MAXDEVNAME);
+ if (len == 0 || len >= MAXDEVNAME)
+ return NULL;
+
+ /*
+ * Allocate a device structure.
+ */
+ if ((dev = new device) == NULL)
+ sys_panic("device_create");
+
+ dev->driver = drv;
+ device_register(dev, name, flags);
+ return dev;
+}
+
+#if 0
+/*
+ * Return device's private data.
+ */
+static void *
+device_private(struct device *dev)
+{
+ assert(dev != NULL);
+ assert(dev->private_data != NULL);
+
+ return dev->private_data;
+}
+#endif
+
+/*
+ * Return true if specified device is valid.
+ */
+static int
+device_valid(struct device *dev)
+{
+ struct device *tmp;
+ int found = 0;
+
+ for (tmp = device_list; tmp != NULL; tmp = tmp->next) {
+ if (tmp == dev) {
+ found = 1;
+ break;
+ }
+ }
+ if (found && dev->active)
+ return 1;
+ return 0;
+}
+
+/*
+ * Increment the reference count on an active device.
+ */
+static int
+device_reference(struct device *dev)
+{
+
+ sched_lock();
+ if (!device_valid(dev)) {
+ sched_unlock();
+ return ENODEV;
+ }
+ dev->refcnt++;
+ sched_unlock();
+ return 0;
+}
+
+/*
+ * Decrement the reference count on a device. If the reference
+ * count becomes zero, we can release the resource for the device.
+ */
+static void
+device_release(struct device *dev)
+{
+ struct device **tmp;
+
+ sched_lock();
+ if (--dev->refcnt > 0) {
+ sched_unlock();
+ return;
+ }
+ /*
+ * No more references - we can remove the device.
+ */
+ for (tmp = &device_list; *tmp; tmp = &(*tmp)->next) {
+ if (*tmp == dev) {
+ *tmp = dev->next;
+ break;
+ }
+ }
+ delete dev;
+ sched_unlock();
+}
+
+int
+device_destroy(struct device *dev)
+{
+
+ sched_lock();
+ if (!device_valid(dev)) {
+ sched_unlock();
+ return ENODEV;
+ }
+ dev->active = 0;
+ device_release(dev);
+ sched_unlock();
+ return 0;
+}
+
+/*
+ * device_open - open the specified device.
+ *
+ * Even if the target driver does not have an open
+ * routine, this function does not return an error. By
+ * using this mechanism, an application can check whether
+ * the specific device exists or not. The open mode
+ * should be handled by an each device driver if it is
+ * needed.
+ */
+int
+device_open(const char *name, int mode, struct device **devp)
+{
+ struct devops *ops;
+ struct device *dev;
+ int error;
+
+ sched_lock();
+ if ((dev = device_lookup(name)) == NULL) {
+ sched_unlock();
+ return ENXIO;
+ }
+ error = device_reference(dev);
+ if (error) {
+ sched_unlock();
+ return error;
+ }
+ sched_unlock();
+
+ ops = dev->driver->devops;
+ assert(ops->open != NULL);
+ error = (*ops->open)(dev, mode);
+ *devp = dev;
+
+ device_release(dev);
+ return error;
+}
+
+/*
+ * device_close - close a device.
+ *
+ * Even if the target driver does not have close routine,
+ * this function does not return any errors.
+ */
+int
+device_close(struct device *dev)
+{
+ struct devops *ops;
+ int error;
+
+ if ((error = device_reference(dev)) != 0)
+ return error;
+
+ ops = dev->driver->devops;
+ assert(ops->close != NULL);
+ error = (*ops->close)(dev);
+
+ device_release(dev);
+ return error;
+}
+
+int
+device_read(struct device *dev, struct uio *uio, int ioflags)
+{
+ struct devops *ops;
+ int error;
+
+ if ((error = device_reference(dev)) != 0)
+ return error;
+
+ ops = dev->driver->devops;
+ assert(ops->read != NULL);
+ error = (*ops->read)(dev, uio, ioflags);
+
+ device_release(dev);
+ return error;
+}
+
+int
+device_write(struct device *dev, struct uio *uio, int ioflags)
+{
+ struct devops *ops;
+ int error;
+
+ if ((error = device_reference(dev)) != 0)
+ return error;
+
+ ops = dev->driver->devops;
+ assert(ops->write != NULL);
+ error = (*ops->write)(dev, uio, ioflags);
+
+ device_release(dev);
+ return error;
+}
+
+/*
+ * device_ioctl - I/O control request.
+ *
+ * A command and its argument are completely device dependent.
+ * The ioctl routine of each driver must validate the user buffer
+ * pointed by the arg value.
+ */
+int
+device_ioctl(struct device *dev, u_long cmd, void *arg)
+{
+ struct devops *ops;
+ int error;
+
+ if ((error = device_reference(dev)) != 0)
+ return error;
+
+ ops = dev->driver->devops;
+ assert(ops->ioctl != NULL);
+ error = (*ops->ioctl)(dev, cmd, arg);
+
+ device_release(dev);
+ return error;
+}
+
+#if 0
+/*
+ * Device control - devctl is similar to ioctl, but is invoked from
+ * other device driver rather than from user application.
+ */
+static int
+device_control(struct device *dev, u_long cmd, void *arg)
+{
+ struct devops *ops;
+ int error;
+
+ assert(dev != NULL);
+
+ sched_lock();
+ ops = dev->driver->devops;
+ assert(ops->devctl != NULL);
+ error = (*ops->devctl)(dev, cmd, arg);
+ sched_unlock();
+ return error;
+}
+
+/*
+ * device_broadcast - broadcast devctl command to all device objects.
+ *
+ * If "force" argument is true, we will continue command
+ * notification even if some driver returns an error. In this
+ * case, this routine returns EIO error if at least one driver
+ * returns an error.
+ *
+ * If force argument is false, a kernel stops the command processing
+ * when at least one driver returns an error. In this case,
+ * device_broadcast will return the error code which is returned
+ * by the driver.
+ */
+static int
+device_broadcast(u_long cmd, void *arg, int force)
+{
+ struct device *dev;
+ struct devops *ops;
+ int error, retval = 0;
+
+ sched_lock();
+
+ for (dev = device_list; dev != NULL; dev = dev->next) {
+ /*
+ * Call driver's devctl() routine.
+ */
+ ops = dev->driver->devops;
+ if (ops == NULL)
+ continue;
+
+ assert(ops->devctl != NULL);
+ error = (*ops->devctl)(dev, cmd, arg);
+ if (error) {
+ if (force)
+ retval = EIO;
+ else {
+ retval = error;
+ break;
+ }
+ }
+ }
+ sched_unlock();
+ return retval;
+}
+#endif
+
+/*
+ * Return device information.
+ */
+int
+device_info(struct devinfo *info)
+{
+ u_long target = info->cookie;
+ u_long i = 0;
+ struct device *dev;
+ int error = ESRCH;
+
+ sched_lock();
+ for (dev = device_list; dev != NULL; dev = dev->next) {
+ if (i++ == target) {
+ info->cookie = i;
+ info->id = dev;
+ info->flags = dev->flags;
+ strlcpy(info->name, dev->name, MAXDEVNAME);
+ error = 0;
+ break;
+ }
+ }
+ sched_unlock();
+ return error;
+}
+
+int
+enodev(void)
+{
+ return ENODEV;
+}
+
+int
+nullop(void)
+{
+ return 0;
+}
--
2.20.1
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