/** * @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; inode_lock(d_inode(root)); dentry = d_alloc_name(root, name); if (!dentry) { inode_unlock(d_inode(root)); return -ENOMEM; } inode = oprofilefs_get_inode(root->d_sb, S_IFREG | perm); if (!inode) { dput(dentry); inode_unlock(d_inode(root)); return -ENOMEM; } inode->i_fop = fops; inode->i_private = priv; d_add(dentry, inode); inode_unlock(d_inode(root)); 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; inode_lock(d_inode(parent)); dentry = d_alloc_name(parent, name); if (!dentry) { inode_unlock(d_inode(parent)); return NULL; } inode = oprofilefs_get_inode(parent->d_sb, S_IFDIR | 0755); if (!inode) { dput(dentry); inode_unlock(d_inode(parent)); return NULL; } inode->i_op = &simple_dir_inode_operations; inode->i_fop = &simple_dir_operations; d_add(dentry, inode); inode_unlock(d_inode(parent)); return dentry; } static int oprofilefs_fill_super(struct super_block *sb, void *data, int silent) { struct inode *root_inode; sb->s_blocksize = PAGE_SIZE; sb->s_blocksize_bits = PAGE_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); }