--- /dev/null
+/**
+ * @file oprofilefs.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/oprofile.h>
+#include <linux/fs.h>
+#include <linux/pagemap.h>
+#include <asm/uaccess.h>
+
+#include "oprof.h"
+
+#define OPROFILEFS_MAGIC 0x6f70726f
+
+DEFINE_RAW_SPINLOCK(oprofilefs_lock);
+
+static struct inode *oprofilefs_get_inode(struct super_block *sb, int mode)
+{
+ struct inode *inode = new_inode(sb);
+
+ if (inode) {
+ inode->i_ino = get_next_ino();
+ 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,
+};
+
+
+ssize_t oprofilefs_str_to_user(char const *str, char __user *buf, size_t count, loff_t *offset)
+{
+ return simple_read_from_buffer(buf, count, offset, str, strlen(str));
+}
+
+
+#define TMPBUFSIZE 50
+
+ssize_t oprofilefs_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);
+}
+
+
+/*
+ * Note: If oprofilefs_ulong_from_user() returns 0, then *val remains
+ * unchanged and might be uninitialized. This follows write syscall
+ * implementation when count is zero: "If count is zero ... [and if]
+ * no errors are detected, 0 will be returned without causing any
+ * other effect." (man 2 write)
+ */
+int oprofilefs_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;
+
+ raw_spin_lock_irqsave(&oprofilefs_lock, flags);
+ *val = simple_strtoul(tmpbuf, NULL, 0);
+ raw_spin_unlock_irqrestore(&oprofilefs_lock, flags);
+ return count;
+}
+
+
+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 oprofilefs_ulong_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;
+ int retval;
+
+ if (*offset)
+ return -EINVAL;
+
+ retval = oprofilefs_ulong_from_user(&value, buf, count);
+ if (retval <= 0)
+ return retval;
+
+ retval = oprofile_set_ulong(file->private_data, value);
+ if (retval)
+ return retval;
+
+ return count;
+}
+
+
+static const struct file_operations ulong_fops = {
+ .read = ulong_read_file,
+ .write = ulong_write_file,
+ .open = simple_open,
+ .llseek = default_llseek,
+};
+
+
+static const struct file_operations ulong_ro_fops = {
+ .read = ulong_read_file,
+ .open = simple_open,
+ .llseek = default_llseek,
+};
+
+
+static int __oprofilefs_create_file(struct dentry *root, char const *name,
+ const struct file_operations *fops, int perm, void *priv)
+{
+ struct dentry *dentry;
+ struct inode *inode;
+
+ mutex_lock(&d_inode(root)->i_mutex);
+ dentry = d_alloc_name(root, name);
+ if (!dentry) {
+ mutex_unlock(&d_inode(root)->i_mutex);
+ return -ENOMEM;
+ }
+ inode = oprofilefs_get_inode(root->d_sb, S_IFREG | perm);
+ if (!inode) {
+ dput(dentry);
+ mutex_unlock(&d_inode(root)->i_mutex);
+ return -ENOMEM;
+ }
+ inode->i_fop = fops;
+ inode->i_private = priv;
+ d_add(dentry, inode);
+ mutex_unlock(&d_inode(root)->i_mutex);
+ return 0;
+}
+
+
+int oprofilefs_create_ulong(struct dentry *root,
+ char const *name, unsigned long *val)
+{
+ return __oprofilefs_create_file(root, name,
+ &ulong_fops, 0644, val);
+}
+
+
+int oprofilefs_create_ro_ulong(struct dentry *root,
+ char const *name, unsigned long *val)
+{
+ return __oprofilefs_create_file(root, name,
+ &ulong_ro_fops, 0444, val);
+}
+
+
+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 oprofilefs_ulong_to_user(atomic_read(val), buf, count, offset);
+}
+
+
+static const struct file_operations atomic_ro_fops = {
+ .read = atomic_read_file,
+ .open = simple_open,
+ .llseek = default_llseek,
+};
+
+
+int oprofilefs_create_ro_atomic(struct dentry *root,
+ char const *name, atomic_t *val)
+{
+ return __oprofilefs_create_file(root, name,
+ &atomic_ro_fops, 0444, val);
+}
+
+
+int oprofilefs_create_file(struct dentry *root,
+ char const *name, const struct file_operations *fops)
+{
+ return __oprofilefs_create_file(root, name, fops, 0644, NULL);
+}
+
+
+int oprofilefs_create_file_perm(struct dentry *root,
+ char const *name, const struct file_operations *fops, int perm)
+{
+ return __oprofilefs_create_file(root, name, fops, perm, NULL);
+}
+
+
+struct dentry *oprofilefs_mkdir(struct dentry *parent, char const *name)
+{
+ struct dentry *dentry;
+ struct inode *inode;
+
+ mutex_lock(&d_inode(parent)->i_mutex);
+ dentry = d_alloc_name(parent, name);
+ if (!dentry) {
+ mutex_unlock(&d_inode(parent)->i_mutex);
+ return NULL;
+ }
+ inode = oprofilefs_get_inode(parent->d_sb, S_IFDIR | 0755);
+ if (!inode) {
+ dput(dentry);
+ mutex_unlock(&d_inode(parent)->i_mutex);
+ return NULL;
+ }
+ inode->i_op = &simple_dir_inode_operations;
+ inode->i_fop = &simple_dir_operations;
+ d_add(dentry, inode);
+ mutex_unlock(&d_inode(parent)->i_mutex);
+ return dentry;
+}
+
+
+static int oprofilefs_fill_super(struct super_block *sb, void *data, int silent)
+{
+ struct inode *root_inode;
+
+ sb->s_blocksize = PAGE_CACHE_SIZE;
+ sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
+ sb->s_magic = OPROFILEFS_MAGIC;
+ sb->s_op = &s_ops;
+ sb->s_time_gran = 1;
+
+ root_inode = oprofilefs_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;
+ sb->s_root = d_make_root(root_inode);
+ if (!sb->s_root)
+ return -ENOMEM;
+
+ oprofile_create_files(sb->s_root);
+
+ // FIXME: verify kill_litter_super removes our dentries
+ return 0;
+}
+
+
+static struct dentry *oprofilefs_mount(struct file_system_type *fs_type,
+ int flags, const char *dev_name, void *data)
+{
+ return mount_single(fs_type, flags, data, oprofilefs_fill_super);
+}
+
+
+static struct file_system_type oprofilefs_type = {
+ .owner = THIS_MODULE,
+ .name = "oprofilefs",
+ .mount = oprofilefs_mount,
+ .kill_sb = kill_litter_super,
+};
+MODULE_ALIAS_FS("oprofilefs");
+
+
+int __init oprofilefs_register(void)
+{
+ return register_filesystem(&oprofilefs_type);
+}
+
+
+void __exit oprofilefs_unregister(void)
+{
+ unregister_filesystem(&oprofilefs_type);
+}
Code Review / kvmfornfv.git / blobdiff