drivers/gator/gator_fs.c - arm/linux-arm-legacy - Git at Google

 /**
  * @file gatorfs.c
  *
  * @remark Copyright 2002 OProfile authors
  * @remark Read the file COPYING
  *
  * @author John Levon
  *
  * A simple filesystem for configuration and
  * access of oprofile.
  */

 #include <linux/init.h>
 #include <linux/module.h>
 #include <linux/fs.h>
 #include <linux/pagemap.h>
 #include <asm/uaccess.h>

 #define gatorfs_MAGIC 0x24051020
 #define TMPBUFSIZE 50
 DEFINE_SPINLOCK(gatorfs_lock);

 static struct inode *gatorfs_get_inode(struct super_block *sb, int mode)
 {
 	struct inode *inode = new_inode(sb);

 	if (inode) {
 #if LINUX_VERSION_CODE >= KERNEL_VERSION(2, 6, 37)
 		inode->i_ino = get_next_ino();
 #endif
 		inode->i_mode = mode;
 		inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
 	}
 	return inode;
 }

 static const struct super_operations s_ops = {
 	.statfs = simple_statfs,
 	.drop_inode = generic_delete_inode,
 };

 static ssize_t gatorfs_ulong_to_user(unsigned long val, char __user *buf, size_t count, loff_t *offset)
 {
 	char tmpbuf[TMPBUFSIZE];
 	size_t maxlen = snprintf(tmpbuf, TMPBUFSIZE, "%lu\n", val);
 	if (maxlen > TMPBUFSIZE)
 		maxlen = TMPBUFSIZE;
 	return simple_read_from_buffer(buf, count, offset, tmpbuf, maxlen);
 }

 static ssize_t gatorfs_u64_to_user(u64 val, char __user *buf, size_t count, loff_t *offset)
 {
 	char tmpbuf[TMPBUFSIZE];
 	size_t maxlen = snprintf(tmpbuf, TMPBUFSIZE, "%llu\n", val);
 	if (maxlen > TMPBUFSIZE)
 		maxlen = TMPBUFSIZE;
 	return simple_read_from_buffer(buf, count, offset, tmpbuf, maxlen);
 }

 static int gatorfs_ulong_from_user(unsigned long *val, char const __user *buf, size_t count)
 {
 	char tmpbuf[TMPBUFSIZE];
 	unsigned long flags;

 	if (!count)
 		return 0;

 	if (count > TMPBUFSIZE - 1)
 		return -EINVAL;

 	memset(tmpbuf, 0x0, TMPBUFSIZE);

 	if (copy_from_user(tmpbuf, buf, count))
 		return -EFAULT;

 	spin_lock_irqsave(&gatorfs_lock, flags);
 	*val = simple_strtoul(tmpbuf, NULL, 0);
 	spin_unlock_irqrestore(&gatorfs_lock, flags);
 	return 0;
 }

 static int gatorfs_u64_from_user(u64 *val, char const __user *buf, size_t count)
 {
 	char tmpbuf[TMPBUFSIZE];
 	unsigned long flags;

 	if (!count)
 		return 0;

 	if (count > TMPBUFSIZE - 1)
 		return -EINVAL;

 	memset(tmpbuf, 0x0, TMPBUFSIZE);

 	if (copy_from_user(tmpbuf, buf, count))
 		return -EFAULT;

 	spin_lock_irqsave(&gatorfs_lock, flags);
 	*val = simple_strtoull(tmpbuf, NULL, 0);
 	spin_unlock_irqrestore(&gatorfs_lock, flags);
 	return 0;
 }

 static ssize_t ulong_read_file(struct file *file, char __user *buf, size_t count, loff_t *offset)
 {
 	unsigned long *val = file->private_data;
 	return gatorfs_ulong_to_user(*val, buf, count, offset);
 }

 static ssize_t u64_read_file(struct file *file, char __user *buf, size_t count, loff_t *offset)
 {
 	u64 *val = file->private_data;
 	return gatorfs_u64_to_user(*val, buf, count, offset);
 }

 static ssize_t ulong_write_file(struct file *file, char const __user *buf, size_t count, loff_t *offset)
 {
 	unsigned long *value = file->private_data;
 	int retval;

 	if (*offset)
 		return -EINVAL;

 	retval = gatorfs_ulong_from_user(value, buf, count);

 	if (retval)
 		return retval;
 	return count;
 }

 static ssize_t u64_write_file(struct file *file, char const __user *buf, size_t count, loff_t *offset)
 {
 	u64 *value = file->private_data;
 	int retval;

 	if (*offset)
 		return -EINVAL;

 	retval = gatorfs_u64_from_user(value, buf, count);

 	if (retval)
 		return retval;
 	return count;
 }

 static int default_open(struct inode *inode, struct file *filp)
 {
 	if (inode->i_private)
 		filp->private_data = inode->i_private;
 	return 0;
 }

 static const struct file_operations ulong_fops = {
 	.read = ulong_read_file,
 	.write = ulong_write_file,
 	.open = default_open,
 };

 static const struct file_operations u64_fops = {
 	.read = u64_read_file,
 	.write = u64_write_file,
 	.open = default_open,
 };

 static const struct file_operations ulong_ro_fops = {
 	.read = ulong_read_file,
 	.open = default_open,
 };

 static const struct file_operations u64_ro_fops = {
 	.read = u64_read_file,
 	.open = default_open,
 };

 static struct dentry *__gatorfs_create_file(struct super_block *sb,
 					    struct dentry *root,
 					    char const *name,
 					    const struct file_operations *fops,
 					    int perm)
 {
 	struct dentry *dentry;
 	struct inode *inode;

 	dentry = d_alloc_name(root, name);
 	if (!dentry)
 		return NULL;
 	inode = gatorfs_get_inode(sb, S_IFREG | perm);
 	if (!inode) {
 		dput(dentry);
 		return NULL;
 	}
 	inode->i_fop = fops;
 	d_add(dentry, inode);
 	return dentry;
 }

 int gatorfs_create_ulong(struct super_block *sb, struct dentry *root,
 			 char const *name, unsigned long *val)
 {
 	struct dentry *d = __gatorfs_create_file(sb, root, name,
 						 &ulong_fops, 0644);
 	if (!d)
 		return -EFAULT;

 	d->d_inode->i_private = val;
 	return 0;
 }

 static int gatorfs_create_u64(struct super_block *sb, struct dentry *root,
 			      char const *name, u64 *val)
 {
 	struct dentry *d = __gatorfs_create_file(sb, root, name,
 						 &u64_fops, 0644);
 	if (!d)
 		return -EFAULT;

 	d->d_inode->i_private = val;
 	return 0;
 }

 int gatorfs_create_ro_ulong(struct super_block *sb, struct dentry *root,
 			    char const *name, unsigned long *val)
 {
 	struct dentry *d = __gatorfs_create_file(sb, root, name,
 						 &ulong_ro_fops, 0444);
 	if (!d)
 		return -EFAULT;

 	d->d_inode->i_private = val;
 	return 0;
 }

 static int gatorfs_create_ro_u64(struct super_block *sb, struct dentry *root,
 				 char const *name, u64 * val)
 {
 	struct dentry *d =
 	    __gatorfs_create_file(sb, root, name, &u64_ro_fops, 0444);
 	if (!d)
 		return -EFAULT;

 	d->d_inode->i_private = val;
 	return 0;
 }

 static ssize_t atomic_read_file(struct file *file, char __user *buf, size_t count, loff_t *offset)
 {
 	atomic_t *val = file->private_data;
 	return gatorfs_ulong_to_user(atomic_read(val), buf, count, offset);
 }

 static const struct file_operations atomic_ro_fops = {
 	.read = atomic_read_file,
 	.open = default_open,
 };

 static int gatorfs_create_file(struct super_block *sb, struct dentry *root,
 			       char const *name, const struct file_operations *fops)
 {
 	if (!__gatorfs_create_file(sb, root, name, fops, 0644))
 		return -EFAULT;
 	return 0;
 }

 static int gatorfs_create_file_perm(struct super_block *sb, struct dentry *root,
 				    char const *name,
 				    const struct file_operations *fops, int perm)
 {
 	if (!__gatorfs_create_file(sb, root, name, fops, perm))
 		return -EFAULT;
 	return 0;
 }

 struct dentry *gatorfs_mkdir(struct super_block *sb,
 			     struct dentry *root, char const *name)
 {
 	struct dentry *dentry;
 	struct inode *inode;

 	dentry = d_alloc_name(root, name);
 	if (!dentry)
 		return NULL;
 	inode = gatorfs_get_inode(sb, S_IFDIR | 0755);
 	if (!inode) {
 		dput(dentry);
 		return NULL;
 	}
 	inode->i_op = &simple_dir_inode_operations;
 	inode->i_fop = &simple_dir_operations;
 	d_add(dentry, inode);
 	return dentry;
 }

 static int gatorfs_fill_super(struct super_block *sb, void *data, int silent)
 {
 	struct inode *root_inode;
 	struct dentry *root_dentry;

 	sb->s_blocksize = PAGE_CACHE_SIZE;
 	sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
 	sb->s_magic = gatorfs_MAGIC;
 	sb->s_op = &s_ops;
 	sb->s_time_gran = 1;

 	root_inode = gatorfs_get_inode(sb, S_IFDIR | 0755);
 	if (!root_inode)
 		return -ENOMEM;
 	root_inode->i_op = &simple_dir_inode_operations;
 	root_inode->i_fop = &simple_dir_operations;

 #if LINUX_VERSION_CODE < KERNEL_VERSION(3, 4, 0)
 	root_dentry = d_alloc_root(root_inode);
 #else
 	root_dentry = d_make_root(root_inode);
 #endif

 	if (!root_dentry) {
 #if LINUX_VERSION_CODE < KERNEL_VERSION(3, 4, 0)
 		iput(root_inode);
 #endif
 		return -ENOMEM;
 	}

 	sb->s_root = root_dentry;

 	gator_op_create_files(sb, root_dentry);

 	return 0;
 }

 #if LINUX_VERSION_CODE < KERNEL_VERSION(2, 6, 39)
 static int gatorfs_get_sb(struct file_system_type *fs_type,
 			  int flags, const char *dev_name, void *data,
 			  struct vfsmount *mnt)
 {
 	return get_sb_single(fs_type, flags, data, gatorfs_fill_super, mnt);
 }
 #else
 static struct dentry *gatorfs_mount(struct file_system_type *fs_type,
 				    int flags, const char *dev_name, void *data)
 {
 	return mount_nodev(fs_type, flags, data, gatorfs_fill_super);
 }
 #endif

 static struct file_system_type gatorfs_type = {
 	.owner = THIS_MODULE,
 	.name = "gatorfs",
 #if LINUX_VERSION_CODE < KERNEL_VERSION(2, 6, 39)
 	.get_sb = gatorfs_get_sb,
 #else
 	.mount = gatorfs_mount,
 #endif

 	.kill_sb = kill_litter_super,
 };

 static int __init gatorfs_register(void)
 {
 	return register_filesystem(&gatorfs_type);
 }

 static void gatorfs_unregister(void)
 {
 	unregister_filesystem(&gatorfs_type);
 }
	/**
	* @file gatorfs.c
	*
	* @remark Copyright 2002 OProfile authors
	* @remark Read the file COPYING
	*
	* @author John Levon
	*
	* A simple filesystem for configuration and
	* access of oprofile.
	*/

	#include <linux/init.h>
	#include <linux/module.h>
	#include <linux/fs.h>
	#include <linux/pagemap.h>
	#include <asm/uaccess.h>

	#define gatorfs_MAGIC 0x24051020
	#define TMPBUFSIZE 50
	DEFINE_SPINLOCK(gatorfs_lock);

	static struct inode gatorfs_get_inode(struct super_block sb, int mode)
	{
	struct inode *inode = new_inode(sb);

	if (inode) {
	#if LINUX_VERSION_CODE >= KERNEL_VERSION(2, 6, 37)
	inode->i_ino = get_next_ino();
	#endif
	inode->i_mode = mode;
	inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
	}
	return inode;
	}

	static const struct super_operations s_ops = {
	.statfs = simple_statfs,
	.drop_inode = generic_delete_inode,
	};

	static ssize_t gatorfs_ulong_to_user(unsigned long val, char __user buf, size_t count, loff_t offset)
	{
	char tmpbuf[TMPBUFSIZE];
	size_t maxlen = snprintf(tmpbuf, TMPBUFSIZE, "%lu\n", val);
	if (maxlen > TMPBUFSIZE)
	maxlen = TMPBUFSIZE;
	return simple_read_from_buffer(buf, count, offset, tmpbuf, maxlen);
	}

	static ssize_t gatorfs_u64_to_user(u64 val, char __user buf, size_t count, loff_t offset)
	{
	char tmpbuf[TMPBUFSIZE];
	size_t maxlen = snprintf(tmpbuf, TMPBUFSIZE, "%llu\n", val);
	if (maxlen > TMPBUFSIZE)
	maxlen = TMPBUFSIZE;
	return simple_read_from_buffer(buf, count, offset, tmpbuf, maxlen);
	}

	static int gatorfs_ulong_from_user(unsigned long val, char const __user buf, size_t count)
	{
	char tmpbuf[TMPBUFSIZE];
	unsigned long flags;

	if (!count)
	return 0;

	if (count > TMPBUFSIZE - 1)
	return -EINVAL;

	memset(tmpbuf, 0x0, TMPBUFSIZE);

	if (copy_from_user(tmpbuf, buf, count))
	return -EFAULT;

	spin_lock_irqsave(&gatorfs_lock, flags);
	*val = simple_strtoul(tmpbuf, NULL, 0);
	spin_unlock_irqrestore(&gatorfs_lock, flags);
	return 0;
	}

	static int gatorfs_u64_from_user(u64 val, char const __user buf, size_t count)
	{
	char tmpbuf[TMPBUFSIZE];
	unsigned long flags;

	if (!count)
	return 0;

	if (count > TMPBUFSIZE - 1)
	return -EINVAL;

	memset(tmpbuf, 0x0, TMPBUFSIZE);

	if (copy_from_user(tmpbuf, buf, count))
	return -EFAULT;

	spin_lock_irqsave(&gatorfs_lock, flags);
	*val = simple_strtoull(tmpbuf, NULL, 0);
	spin_unlock_irqrestore(&gatorfs_lock, flags);
	return 0;
	}

	static ssize_t ulong_read_file(struct file file, char __user buf, size_t count, loff_t *offset)
	{
	unsigned long *val = file->private_data;
	return gatorfs_ulong_to_user(*val, buf, count, offset);
	}

	static ssize_t u64_read_file(struct file file, char __user buf, size_t count, loff_t *offset)
	{
	u64 *val = file->private_data;
	return gatorfs_u64_to_user(*val, buf, count, offset);
	}

	static ssize_t ulong_write_file(struct file file, char const __user buf, size_t count, loff_t *offset)
	{
	unsigned long *value = file->private_data;
	int retval;

	if (*offset)
	return -EINVAL;

	retval = gatorfs_ulong_from_user(value, buf, count);

	if (retval)
	return retval;
	return count;
	}

	static ssize_t u64_write_file(struct file file, char const __user buf, size_t count, loff_t *offset)
	{
	u64 *value = file->private_data;
	int retval;

	if (*offset)
	return -EINVAL;

	retval = gatorfs_u64_from_user(value, buf, count);

	if (retval)
	return retval;
	return count;
	}

	static int default_open(struct inode inode, struct file filp)
	{
	if (inode->i_private)
	filp->private_data = inode->i_private;
	return 0;
	}

	static const struct file_operations ulong_fops = {
	.read = ulong_read_file,
	.write = ulong_write_file,
	.open = default_open,
	};

	static const struct file_operations u64_fops = {
	.read = u64_read_file,
	.write = u64_write_file,
	.open = default_open,
	};

	static const struct file_operations ulong_ro_fops = {
	.read = ulong_read_file,
	.open = default_open,
	};

	static const struct file_operations u64_ro_fops = {
	.read = u64_read_file,
	.open = default_open,
	};

	static struct dentry __gatorfs_create_file(struct super_block sb,
	struct dentry *root,
	char const *name,
	const struct file_operations *fops,
	int perm)
	{
	struct dentry *dentry;
	struct inode *inode;

	dentry = d_alloc_name(root, name);
	if (!dentry)
	return NULL;
	inode = gatorfs_get_inode(sb, S_IFREG \| perm);
	if (!inode) {
	dput(dentry);
	return NULL;
	}
	inode->i_fop = fops;
	d_add(dentry, inode);
	return dentry;
	}

	int gatorfs_create_ulong(struct super_block sb, struct dentry root,
	char const name, unsigned long val)
	{
	struct dentry *d = __gatorfs_create_file(sb, root, name,
	&ulong_fops, 0644);
	if (!d)
	return -EFAULT;

	d->d_inode->i_private = val;
	return 0;
	}

	static int gatorfs_create_u64(struct super_block sb, struct dentry root,
	char const name, u64 val)
	{
	struct dentry *d = __gatorfs_create_file(sb, root, name,
	&u64_fops, 0644);
	if (!d)
	return -EFAULT;

	d->d_inode->i_private = val;
	return 0;
	}

	int gatorfs_create_ro_ulong(struct super_block sb, struct dentry root,
	char const name, unsigned long val)
	{
	struct dentry *d = __gatorfs_create_file(sb, root, name,
	&ulong_ro_fops, 0444);
	if (!d)
	return -EFAULT;

	d->d_inode->i_private = val;
	return 0;
	}

	static int gatorfs_create_ro_u64(struct super_block sb, struct dentry root,
	char const name, u64 val)
	{
	struct dentry *d =
	__gatorfs_create_file(sb, root, name, &u64_ro_fops, 0444);
	if (!d)
	return -EFAULT;

	d->d_inode->i_private = val;
	return 0;
	}

	static ssize_t atomic_read_file(struct file file, char __user buf, size_t count, loff_t *offset)
	{
	atomic_t *val = file->private_data;
	return gatorfs_ulong_to_user(atomic_read(val), buf, count, offset);
	}

	static const struct file_operations atomic_ro_fops = {
	.read = atomic_read_file,
	.open = default_open,
	};

	static int gatorfs_create_file(struct super_block sb, struct dentry root,
	char const name, const struct file_operations fops)
	{
	if (!__gatorfs_create_file(sb, root, name, fops, 0644))
	return -EFAULT;
	return 0;
	}

	static int gatorfs_create_file_perm(struct super_block sb, struct dentry root,
	char const *name,
	const struct file_operations *fops, int perm)
	{
	if (!__gatorfs_create_file(sb, root, name, fops, perm))
	return -EFAULT;
	return 0;
	}

	struct dentry gatorfs_mkdir(struct super_block sb,
	struct dentry root, char const name)
	{
	struct dentry *dentry;
	struct inode *inode;

	dentry = d_alloc_name(root, name);
	if (!dentry)
	return NULL;
	inode = gatorfs_get_inode(sb, S_IFDIR \| 0755);
	if (!inode) {
	dput(dentry);
	return NULL;
	}
	inode->i_op = &simple_dir_inode_operations;
	inode->i_fop = &simple_dir_operations;
	d_add(dentry, inode);
	return dentry;
	}

	static int gatorfs_fill_super(struct super_block sb, void data, int silent)
	{
	struct inode *root_inode;
	struct dentry *root_dentry;

	sb->s_blocksize = PAGE_CACHE_SIZE;
	sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
	sb->s_magic = gatorfs_MAGIC;
	sb->s_op = &s_ops;
	sb->s_time_gran = 1;

	root_inode = gatorfs_get_inode(sb, S_IFDIR \| 0755);
	if (!root_inode)
	return -ENOMEM;
	root_inode->i_op = &simple_dir_inode_operations;
	root_inode->i_fop = &simple_dir_operations;

	#if LINUX_VERSION_CODE < KERNEL_VERSION(3, 4, 0)
	root_dentry = d_alloc_root(root_inode);
	#else
	root_dentry = d_make_root(root_inode);
	#endif

	if (!root_dentry) {
	#if LINUX_VERSION_CODE < KERNEL_VERSION(3, 4, 0)
	iput(root_inode);
	#endif
	return -ENOMEM;
	}

	sb->s_root = root_dentry;

	gator_op_create_files(sb, root_dentry);

	return 0;
	}

	#if LINUX_VERSION_CODE < KERNEL_VERSION(2, 6, 39)
	static int gatorfs_get_sb(struct file_system_type *fs_type,
	int flags, const char dev_name, void data,
	struct vfsmount *mnt)
	{
	return get_sb_single(fs_type, flags, data, gatorfs_fill_super, mnt);
	}
	#else
	static struct dentry gatorfs_mount(struct file_system_type fs_type,
	int flags, const char dev_name, void data)
	{
	return mount_nodev(fs_type, flags, data, gatorfs_fill_super);
	}
	#endif

	static struct file_system_type gatorfs_type = {
	.owner = THIS_MODULE,
	.name = "gatorfs",
	#if LINUX_VERSION_CODE < KERNEL_VERSION(2, 6, 39)
	.get_sb = gatorfs_get_sb,
	#else
	.mount = gatorfs_mount,
	#endif

	.kill_sb = kill_litter_super,
	};

	static int __init gatorfs_register(void)
	{
	return register_filesystem(&gatorfs_type);
	}

	static void gatorfs_unregister(void)
	{
	unregister_filesystem(&gatorfs_type);
	}