| // SPDX-License-Identifier: GPL-1.0+ |
| /* |
| * Hypervisor filesystem for Linux on s390. |
| * |
| * Copyright IBM Corp. 2006, 2008 |
| * Author(s): Michael Holzheu <holzheu@de.ibm.com> |
| */ |
| |
| #define KMSG_COMPONENT "hypfs" |
| #define pr_fmt(fmt) KMSG_COMPONENT ": " fmt |
| |
| #include <linux/types.h> |
| #include <linux/errno.h> |
| #include <linux/fs.h> |
| #include <linux/fs_context.h> |
| #include <linux/fs_parser.h> |
| #include <linux/namei.h> |
| #include <linux/vfs.h> |
| #include <linux/slab.h> |
| #include <linux/pagemap.h> |
| #include <linux/time.h> |
| #include <linux/sysfs.h> |
| #include <linux/init.h> |
| #include <linux/kobject.h> |
| #include <linux/seq_file.h> |
| #include <linux/uio.h> |
| #include <asm/ebcdic.h> |
| #include "hypfs.h" |
| |
| #define HYPFS_MAGIC 0x687970 /* ASCII 'hyp' */ |
| #define TMP_SIZE 64 /* size of temporary buffers */ |
| |
| static struct dentry *hypfs_create_update_file(struct dentry *dir); |
| |
| struct hypfs_sb_info { |
| kuid_t uid; /* uid used for files and dirs */ |
| kgid_t gid; /* gid used for files and dirs */ |
| struct dentry *update_file; /* file to trigger update */ |
| time64_t last_update; /* last update, CLOCK_MONOTONIC time */ |
| struct mutex lock; /* lock to protect update process */ |
| }; |
| |
| static const struct file_operations hypfs_file_ops; |
| static struct file_system_type hypfs_type; |
| static const struct super_operations hypfs_s_ops; |
| |
| /* start of list of all dentries, which have to be deleted on update */ |
| static struct dentry *hypfs_last_dentry; |
| |
| static void hypfs_update_update(struct super_block *sb) |
| { |
| struct hypfs_sb_info *sb_info = sb->s_fs_info; |
| struct inode *inode = d_inode(sb_info->update_file); |
| |
| sb_info->last_update = ktime_get_seconds(); |
| inode->i_atime = inode->i_mtime = inode_set_ctime_current(inode); |
| } |
| |
| /* directory tree removal functions */ |
| |
| static void hypfs_add_dentry(struct dentry *dentry) |
| { |
| dentry->d_fsdata = hypfs_last_dentry; |
| hypfs_last_dentry = dentry; |
| } |
| |
| static void hypfs_remove(struct dentry *dentry) |
| { |
| struct dentry *parent; |
| |
| parent = dentry->d_parent; |
| inode_lock(d_inode(parent)); |
| if (simple_positive(dentry)) { |
| if (d_is_dir(dentry)) |
| simple_rmdir(d_inode(parent), dentry); |
| else |
| simple_unlink(d_inode(parent), dentry); |
| } |
| d_drop(dentry); |
| dput(dentry); |
| inode_unlock(d_inode(parent)); |
| } |
| |
| static void hypfs_delete_tree(struct dentry *root) |
| { |
| while (hypfs_last_dentry) { |
| struct dentry *next_dentry; |
| next_dentry = hypfs_last_dentry->d_fsdata; |
| hypfs_remove(hypfs_last_dentry); |
| hypfs_last_dentry = next_dentry; |
| } |
| } |
| |
| static struct inode *hypfs_make_inode(struct super_block *sb, umode_t mode) |
| { |
| struct inode *ret = new_inode(sb); |
| |
| if (ret) { |
| struct hypfs_sb_info *hypfs_info = sb->s_fs_info; |
| ret->i_ino = get_next_ino(); |
| ret->i_mode = mode; |
| ret->i_uid = hypfs_info->uid; |
| ret->i_gid = hypfs_info->gid; |
| ret->i_atime = ret->i_mtime = inode_set_ctime_current(ret); |
| if (S_ISDIR(mode)) |
| set_nlink(ret, 2); |
| } |
| return ret; |
| } |
| |
| static void hypfs_evict_inode(struct inode *inode) |
| { |
| clear_inode(inode); |
| kfree(inode->i_private); |
| } |
| |
| static int hypfs_open(struct inode *inode, struct file *filp) |
| { |
| char *data = file_inode(filp)->i_private; |
| struct hypfs_sb_info *fs_info; |
| |
| if (filp->f_mode & FMODE_WRITE) { |
| if (!(inode->i_mode & S_IWUGO)) |
| return -EACCES; |
| } |
| if (filp->f_mode & FMODE_READ) { |
| if (!(inode->i_mode & S_IRUGO)) |
| return -EACCES; |
| } |
| |
| fs_info = inode->i_sb->s_fs_info; |
| if(data) { |
| mutex_lock(&fs_info->lock); |
| filp->private_data = kstrdup(data, GFP_KERNEL); |
| if (!filp->private_data) { |
| mutex_unlock(&fs_info->lock); |
| return -ENOMEM; |
| } |
| mutex_unlock(&fs_info->lock); |
| } |
| return nonseekable_open(inode, filp); |
| } |
| |
| static ssize_t hypfs_read_iter(struct kiocb *iocb, struct iov_iter *to) |
| { |
| struct file *file = iocb->ki_filp; |
| char *data = file->private_data; |
| size_t available = strlen(data); |
| loff_t pos = iocb->ki_pos; |
| size_t count; |
| |
| if (pos < 0) |
| return -EINVAL; |
| if (pos >= available || !iov_iter_count(to)) |
| return 0; |
| count = copy_to_iter(data + pos, available - pos, to); |
| if (!count) |
| return -EFAULT; |
| iocb->ki_pos = pos + count; |
| file_accessed(file); |
| return count; |
| } |
| |
| static ssize_t hypfs_write_iter(struct kiocb *iocb, struct iov_iter *from) |
| { |
| int rc; |
| struct super_block *sb = file_inode(iocb->ki_filp)->i_sb; |
| struct hypfs_sb_info *fs_info = sb->s_fs_info; |
| size_t count = iov_iter_count(from); |
| |
| /* |
| * Currently we only allow one update per second for two reasons: |
| * 1. diag 204 is VERY expensive |
| * 2. If several processes do updates in parallel and then read the |
| * hypfs data, the likelihood of collisions is reduced, if we restrict |
| * the minimum update interval. A collision occurs, if during the |
| * data gathering of one process another process triggers an update |
| * If the first process wants to ensure consistent data, it has |
| * to restart data collection in this case. |
| */ |
| mutex_lock(&fs_info->lock); |
| if (fs_info->last_update == ktime_get_seconds()) { |
| rc = -EBUSY; |
| goto out; |
| } |
| hypfs_delete_tree(sb->s_root); |
| if (MACHINE_IS_VM) |
| rc = hypfs_vm_create_files(sb->s_root); |
| else |
| rc = hypfs_diag_create_files(sb->s_root); |
| if (rc) { |
| pr_err("Updating the hypfs tree failed\n"); |
| hypfs_delete_tree(sb->s_root); |
| goto out; |
| } |
| hypfs_update_update(sb); |
| rc = count; |
| iov_iter_advance(from, count); |
| out: |
| mutex_unlock(&fs_info->lock); |
| return rc; |
| } |
| |
| static int hypfs_release(struct inode *inode, struct file *filp) |
| { |
| kfree(filp->private_data); |
| return 0; |
| } |
| |
| enum { Opt_uid, Opt_gid, }; |
| |
| static const struct fs_parameter_spec hypfs_fs_parameters[] = { |
| fsparam_u32("gid", Opt_gid), |
| fsparam_u32("uid", Opt_uid), |
| {} |
| }; |
| |
| static int hypfs_parse_param(struct fs_context *fc, struct fs_parameter *param) |
| { |
| struct hypfs_sb_info *hypfs_info = fc->s_fs_info; |
| struct fs_parse_result result; |
| kuid_t uid; |
| kgid_t gid; |
| int opt; |
| |
| opt = fs_parse(fc, hypfs_fs_parameters, param, &result); |
| if (opt < 0) |
| return opt; |
| |
| switch (opt) { |
| case Opt_uid: |
| uid = make_kuid(current_user_ns(), result.uint_32); |
| if (!uid_valid(uid)) |
| return invalf(fc, "Unknown uid"); |
| hypfs_info->uid = uid; |
| break; |
| case Opt_gid: |
| gid = make_kgid(current_user_ns(), result.uint_32); |
| if (!gid_valid(gid)) |
| return invalf(fc, "Unknown gid"); |
| hypfs_info->gid = gid; |
| break; |
| } |
| return 0; |
| } |
| |
| static int hypfs_show_options(struct seq_file *s, struct dentry *root) |
| { |
| struct hypfs_sb_info *hypfs_info = root->d_sb->s_fs_info; |
| |
| seq_printf(s, ",uid=%u", from_kuid_munged(&init_user_ns, hypfs_info->uid)); |
| seq_printf(s, ",gid=%u", from_kgid_munged(&init_user_ns, hypfs_info->gid)); |
| return 0; |
| } |
| |
| static int hypfs_fill_super(struct super_block *sb, struct fs_context *fc) |
| { |
| struct hypfs_sb_info *sbi = sb->s_fs_info; |
| struct inode *root_inode; |
| struct dentry *root_dentry, *update_file; |
| int rc; |
| |
| sb->s_blocksize = PAGE_SIZE; |
| sb->s_blocksize_bits = PAGE_SHIFT; |
| sb->s_magic = HYPFS_MAGIC; |
| sb->s_op = &hypfs_s_ops; |
| |
| root_inode = hypfs_make_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 = root_dentry = d_make_root(root_inode); |
| if (!root_dentry) |
| return -ENOMEM; |
| if (MACHINE_IS_VM) |
| rc = hypfs_vm_create_files(root_dentry); |
| else |
| rc = hypfs_diag_create_files(root_dentry); |
| if (rc) |
| return rc; |
| update_file = hypfs_create_update_file(root_dentry); |
| if (IS_ERR(update_file)) |
| return PTR_ERR(update_file); |
| sbi->update_file = update_file; |
| hypfs_update_update(sb); |
| pr_info("Hypervisor filesystem mounted\n"); |
| return 0; |
| } |
| |
| static int hypfs_get_tree(struct fs_context *fc) |
| { |
| return get_tree_single(fc, hypfs_fill_super); |
| } |
| |
| static void hypfs_free_fc(struct fs_context *fc) |
| { |
| kfree(fc->s_fs_info); |
| } |
| |
| static const struct fs_context_operations hypfs_context_ops = { |
| .free = hypfs_free_fc, |
| .parse_param = hypfs_parse_param, |
| .get_tree = hypfs_get_tree, |
| }; |
| |
| static int hypfs_init_fs_context(struct fs_context *fc) |
| { |
| struct hypfs_sb_info *sbi; |
| |
| sbi = kzalloc(sizeof(struct hypfs_sb_info), GFP_KERNEL); |
| if (!sbi) |
| return -ENOMEM; |
| |
| mutex_init(&sbi->lock); |
| sbi->uid = current_uid(); |
| sbi->gid = current_gid(); |
| |
| fc->s_fs_info = sbi; |
| fc->ops = &hypfs_context_ops; |
| return 0; |
| } |
| |
| static void hypfs_kill_super(struct super_block *sb) |
| { |
| struct hypfs_sb_info *sb_info = sb->s_fs_info; |
| |
| if (sb->s_root) |
| hypfs_delete_tree(sb->s_root); |
| if (sb_info && sb_info->update_file) |
| hypfs_remove(sb_info->update_file); |
| kfree(sb->s_fs_info); |
| sb->s_fs_info = NULL; |
| kill_litter_super(sb); |
| } |
| |
| static struct dentry *hypfs_create_file(struct dentry *parent, const char *name, |
| char *data, umode_t mode) |
| { |
| struct dentry *dentry; |
| struct inode *inode; |
| |
| inode_lock(d_inode(parent)); |
| dentry = lookup_one_len(name, parent, strlen(name)); |
| if (IS_ERR(dentry)) { |
| dentry = ERR_PTR(-ENOMEM); |
| goto fail; |
| } |
| inode = hypfs_make_inode(parent->d_sb, mode); |
| if (!inode) { |
| dput(dentry); |
| dentry = ERR_PTR(-ENOMEM); |
| goto fail; |
| } |
| if (S_ISREG(mode)) { |
| inode->i_fop = &hypfs_file_ops; |
| if (data) |
| inode->i_size = strlen(data); |
| else |
| inode->i_size = 0; |
| } else if (S_ISDIR(mode)) { |
| inode->i_op = &simple_dir_inode_operations; |
| inode->i_fop = &simple_dir_operations; |
| inc_nlink(d_inode(parent)); |
| } else |
| BUG(); |
| inode->i_private = data; |
| d_instantiate(dentry, inode); |
| dget(dentry); |
| fail: |
| inode_unlock(d_inode(parent)); |
| return dentry; |
| } |
| |
| struct dentry *hypfs_mkdir(struct dentry *parent, const char *name) |
| { |
| struct dentry *dentry; |
| |
| dentry = hypfs_create_file(parent, name, NULL, S_IFDIR | DIR_MODE); |
| if (IS_ERR(dentry)) |
| return dentry; |
| hypfs_add_dentry(dentry); |
| return dentry; |
| } |
| |
| static struct dentry *hypfs_create_update_file(struct dentry *dir) |
| { |
| struct dentry *dentry; |
| |
| dentry = hypfs_create_file(dir, "update", NULL, |
| S_IFREG | UPDATE_FILE_MODE); |
| /* |
| * We do not put the update file on the 'delete' list with |
| * hypfs_add_dentry(), since it should not be removed when the tree |
| * is updated. |
| */ |
| return dentry; |
| } |
| |
| struct dentry *hypfs_create_u64(struct dentry *dir, |
| const char *name, __u64 value) |
| { |
| char *buffer; |
| char tmp[TMP_SIZE]; |
| struct dentry *dentry; |
| |
| snprintf(tmp, TMP_SIZE, "%llu\n", (unsigned long long int)value); |
| buffer = kstrdup(tmp, GFP_KERNEL); |
| if (!buffer) |
| return ERR_PTR(-ENOMEM); |
| dentry = |
| hypfs_create_file(dir, name, buffer, S_IFREG | REG_FILE_MODE); |
| if (IS_ERR(dentry)) { |
| kfree(buffer); |
| return ERR_PTR(-ENOMEM); |
| } |
| hypfs_add_dentry(dentry); |
| return dentry; |
| } |
| |
| struct dentry *hypfs_create_str(struct dentry *dir, |
| const char *name, char *string) |
| { |
| char *buffer; |
| struct dentry *dentry; |
| |
| buffer = kmalloc(strlen(string) + 2, GFP_KERNEL); |
| if (!buffer) |
| return ERR_PTR(-ENOMEM); |
| sprintf(buffer, "%s\n", string); |
| dentry = |
| hypfs_create_file(dir, name, buffer, S_IFREG | REG_FILE_MODE); |
| if (IS_ERR(dentry)) { |
| kfree(buffer); |
| return ERR_PTR(-ENOMEM); |
| } |
| hypfs_add_dentry(dentry); |
| return dentry; |
| } |
| |
| static const struct file_operations hypfs_file_ops = { |
| .open = hypfs_open, |
| .release = hypfs_release, |
| .read_iter = hypfs_read_iter, |
| .write_iter = hypfs_write_iter, |
| .llseek = no_llseek, |
| }; |
| |
| static struct file_system_type hypfs_type = { |
| .owner = THIS_MODULE, |
| .name = "s390_hypfs", |
| .init_fs_context = hypfs_init_fs_context, |
| .parameters = hypfs_fs_parameters, |
| .kill_sb = hypfs_kill_super |
| }; |
| |
| static const struct super_operations hypfs_s_ops = { |
| .statfs = simple_statfs, |
| .evict_inode = hypfs_evict_inode, |
| .show_options = hypfs_show_options, |
| }; |
| |
| int __init __hypfs_fs_init(void) |
| { |
| int rc; |
| |
| rc = sysfs_create_mount_point(hypervisor_kobj, "s390"); |
| if (rc) |
| return rc; |
| rc = register_filesystem(&hypfs_type); |
| if (rc) |
| goto fail; |
| return 0; |
| fail: |
| sysfs_remove_mount_point(hypervisor_kobj, "s390"); |
| return rc; |
| } |