| /* |
| * linux/fs/proc/inode.c |
| * |
| * Copyright (C) 1991, 1992 Linus Torvalds |
| */ |
| |
| #include <linux/time.h> |
| #include <linux/proc_fs.h> |
| #include <linux/kernel.h> |
| #include <linux/pid_namespace.h> |
| #include <linux/mm.h> |
| #include <linux/string.h> |
| #include <linux/stat.h> |
| #include <linux/completion.h> |
| #include <linux/poll.h> |
| #include <linux/file.h> |
| #include <linux/limits.h> |
| #include <linux/init.h> |
| #include <linux/module.h> |
| #include <linux/sysctl.h> |
| #include <linux/seq_file.h> |
| #include <linux/slab.h> |
| #include <linux/mount.h> |
| |
| #include <asm/system.h> |
| #include <asm/uaccess.h> |
| |
| #include "internal.h" |
| |
| static void proc_evict_inode(struct inode *inode) |
| { |
| struct proc_dir_entry *de; |
| struct ctl_table_header *head; |
| const struct proc_ns_operations *ns_ops; |
| |
| truncate_inode_pages(&inode->i_data, 0); |
| end_writeback(inode); |
| |
| /* Stop tracking associated processes */ |
| put_pid(PROC_I(inode)->pid); |
| |
| /* Let go of any associated proc directory entry */ |
| de = PROC_I(inode)->pde; |
| if (de) |
| pde_put(de); |
| head = PROC_I(inode)->sysctl; |
| if (head) { |
| rcu_assign_pointer(PROC_I(inode)->sysctl, NULL); |
| sysctl_head_put(head); |
| } |
| /* Release any associated namespace */ |
| ns_ops = PROC_I(inode)->ns_ops; |
| if (ns_ops && ns_ops->put) |
| ns_ops->put(PROC_I(inode)->ns); |
| } |
| |
| static struct kmem_cache * proc_inode_cachep; |
| |
| static struct inode *proc_alloc_inode(struct super_block *sb) |
| { |
| struct proc_inode *ei; |
| struct inode *inode; |
| |
| ei = (struct proc_inode *)kmem_cache_alloc(proc_inode_cachep, GFP_KERNEL); |
| if (!ei) |
| return NULL; |
| ei->pid = NULL; |
| ei->fd = 0; |
| ei->op.proc_get_link = NULL; |
| ei->pde = NULL; |
| ei->sysctl = NULL; |
| ei->sysctl_entry = NULL; |
| ei->ns = NULL; |
| ei->ns_ops = NULL; |
| inode = &ei->vfs_inode; |
| inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME; |
| return inode; |
| } |
| |
| static void proc_i_callback(struct rcu_head *head) |
| { |
| struct inode *inode = container_of(head, struct inode, i_rcu); |
| kmem_cache_free(proc_inode_cachep, PROC_I(inode)); |
| } |
| |
| static void proc_destroy_inode(struct inode *inode) |
| { |
| call_rcu(&inode->i_rcu, proc_i_callback); |
| } |
| |
| static void init_once(void *foo) |
| { |
| struct proc_inode *ei = (struct proc_inode *) foo; |
| |
| inode_init_once(&ei->vfs_inode); |
| } |
| |
| void __init proc_init_inodecache(void) |
| { |
| proc_inode_cachep = kmem_cache_create("proc_inode_cache", |
| sizeof(struct proc_inode), |
| 0, (SLAB_RECLAIM_ACCOUNT| |
| SLAB_MEM_SPREAD|SLAB_PANIC), |
| init_once); |
| } |
| |
| static int proc_show_options(struct seq_file *seq, struct dentry *root) |
| { |
| struct super_block *sb = root->d_sb; |
| struct pid_namespace *pid = sb->s_fs_info; |
| |
| if (pid->pid_gid) |
| seq_printf(seq, ",gid=%lu", (unsigned long)pid->pid_gid); |
| if (pid->hide_pid != 0) |
| seq_printf(seq, ",hidepid=%u", pid->hide_pid); |
| |
| return 0; |
| } |
| |
| static const struct super_operations proc_sops = { |
| .alloc_inode = proc_alloc_inode, |
| .destroy_inode = proc_destroy_inode, |
| .drop_inode = generic_delete_inode, |
| .evict_inode = proc_evict_inode, |
| .statfs = simple_statfs, |
| .remount_fs = proc_remount, |
| .show_options = proc_show_options, |
| }; |
| |
| static void __pde_users_dec(struct proc_dir_entry *pde) |
| { |
| pde->pde_users--; |
| if (pde->pde_unload_completion && pde->pde_users == 0) |
| complete(pde->pde_unload_completion); |
| } |
| |
| void pde_users_dec(struct proc_dir_entry *pde) |
| { |
| spin_lock(&pde->pde_unload_lock); |
| __pde_users_dec(pde); |
| spin_unlock(&pde->pde_unload_lock); |
| } |
| |
| static loff_t proc_reg_llseek(struct file *file, loff_t offset, int whence) |
| { |
| struct proc_dir_entry *pde = PDE(file->f_path.dentry->d_inode); |
| loff_t rv = -EINVAL; |
| loff_t (*llseek)(struct file *, loff_t, int); |
| |
| spin_lock(&pde->pde_unload_lock); |
| /* |
| * remove_proc_entry() is going to delete PDE (as part of module |
| * cleanup sequence). No new callers into module allowed. |
| */ |
| if (!pde->proc_fops) { |
| spin_unlock(&pde->pde_unload_lock); |
| return rv; |
| } |
| /* |
| * Bump refcount so that remove_proc_entry will wail for ->llseek to |
| * complete. |
| */ |
| pde->pde_users++; |
| /* |
| * Save function pointer under lock, to protect against ->proc_fops |
| * NULL'ifying right after ->pde_unload_lock is dropped. |
| */ |
| llseek = pde->proc_fops->llseek; |
| spin_unlock(&pde->pde_unload_lock); |
| |
| if (!llseek) |
| llseek = default_llseek; |
| rv = llseek(file, offset, whence); |
| |
| pde_users_dec(pde); |
| return rv; |
| } |
| |
| static ssize_t proc_reg_read(struct file *file, char __user *buf, size_t count, loff_t *ppos) |
| { |
| struct proc_dir_entry *pde = PDE(file->f_path.dentry->d_inode); |
| ssize_t rv = -EIO; |
| ssize_t (*read)(struct file *, char __user *, size_t, loff_t *); |
| |
| spin_lock(&pde->pde_unload_lock); |
| if (!pde->proc_fops) { |
| spin_unlock(&pde->pde_unload_lock); |
| return rv; |
| } |
| pde->pde_users++; |
| read = pde->proc_fops->read; |
| spin_unlock(&pde->pde_unload_lock); |
| |
| if (read) |
| rv = read(file, buf, count, ppos); |
| |
| pde_users_dec(pde); |
| return rv; |
| } |
| |
| static ssize_t proc_reg_write(struct file *file, const char __user *buf, size_t count, loff_t *ppos) |
| { |
| struct proc_dir_entry *pde = PDE(file->f_path.dentry->d_inode); |
| ssize_t rv = -EIO; |
| ssize_t (*write)(struct file *, const char __user *, size_t, loff_t *); |
| |
| spin_lock(&pde->pde_unload_lock); |
| if (!pde->proc_fops) { |
| spin_unlock(&pde->pde_unload_lock); |
| return rv; |
| } |
| pde->pde_users++; |
| write = pde->proc_fops->write; |
| spin_unlock(&pde->pde_unload_lock); |
| |
| if (write) |
| rv = write(file, buf, count, ppos); |
| |
| pde_users_dec(pde); |
| return rv; |
| } |
| |
| static unsigned int proc_reg_poll(struct file *file, struct poll_table_struct *pts) |
| { |
| struct proc_dir_entry *pde = PDE(file->f_path.dentry->d_inode); |
| unsigned int rv = DEFAULT_POLLMASK; |
| unsigned int (*poll)(struct file *, struct poll_table_struct *); |
| |
| spin_lock(&pde->pde_unload_lock); |
| if (!pde->proc_fops) { |
| spin_unlock(&pde->pde_unload_lock); |
| return rv; |
| } |
| pde->pde_users++; |
| poll = pde->proc_fops->poll; |
| spin_unlock(&pde->pde_unload_lock); |
| |
| if (poll) |
| rv = poll(file, pts); |
| |
| pde_users_dec(pde); |
| return rv; |
| } |
| |
| static long proc_reg_unlocked_ioctl(struct file *file, unsigned int cmd, unsigned long arg) |
| { |
| struct proc_dir_entry *pde = PDE(file->f_path.dentry->d_inode); |
| long rv = -ENOTTY; |
| long (*ioctl)(struct file *, unsigned int, unsigned long); |
| |
| spin_lock(&pde->pde_unload_lock); |
| if (!pde->proc_fops) { |
| spin_unlock(&pde->pde_unload_lock); |
| return rv; |
| } |
| pde->pde_users++; |
| ioctl = pde->proc_fops->unlocked_ioctl; |
| spin_unlock(&pde->pde_unload_lock); |
| |
| if (ioctl) |
| rv = ioctl(file, cmd, arg); |
| |
| pde_users_dec(pde); |
| return rv; |
| } |
| |
| #ifdef CONFIG_COMPAT |
| static long proc_reg_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg) |
| { |
| struct proc_dir_entry *pde = PDE(file->f_path.dentry->d_inode); |
| long rv = -ENOTTY; |
| long (*compat_ioctl)(struct file *, unsigned int, unsigned long); |
| |
| spin_lock(&pde->pde_unload_lock); |
| if (!pde->proc_fops) { |
| spin_unlock(&pde->pde_unload_lock); |
| return rv; |
| } |
| pde->pde_users++; |
| compat_ioctl = pde->proc_fops->compat_ioctl; |
| spin_unlock(&pde->pde_unload_lock); |
| |
| if (compat_ioctl) |
| rv = compat_ioctl(file, cmd, arg); |
| |
| pde_users_dec(pde); |
| return rv; |
| } |
| #endif |
| |
| static int proc_reg_mmap(struct file *file, struct vm_area_struct *vma) |
| { |
| struct proc_dir_entry *pde = PDE(file->f_path.dentry->d_inode); |
| int rv = -EIO; |
| int (*mmap)(struct file *, struct vm_area_struct *); |
| |
| spin_lock(&pde->pde_unload_lock); |
| if (!pde->proc_fops) { |
| spin_unlock(&pde->pde_unload_lock); |
| return rv; |
| } |
| pde->pde_users++; |
| mmap = pde->proc_fops->mmap; |
| spin_unlock(&pde->pde_unload_lock); |
| |
| if (mmap) |
| rv = mmap(file, vma); |
| |
| pde_users_dec(pde); |
| return rv; |
| } |
| |
| static int proc_reg_open(struct inode *inode, struct file *file) |
| { |
| struct proc_dir_entry *pde = PDE(inode); |
| int rv = 0; |
| int (*open)(struct inode *, struct file *); |
| int (*release)(struct inode *, struct file *); |
| struct pde_opener *pdeo; |
| |
| /* |
| * What for, you ask? Well, we can have open, rmmod, remove_proc_entry |
| * sequence. ->release won't be called because ->proc_fops will be |
| * cleared. Depending on complexity of ->release, consequences vary. |
| * |
| * We can't wait for mercy when close will be done for real, it's |
| * deadlockable: rmmod foo </proc/foo . So, we're going to do ->release |
| * by hand in remove_proc_entry(). For this, save opener's credentials |
| * for later. |
| */ |
| pdeo = kmalloc(sizeof(struct pde_opener), GFP_KERNEL); |
| if (!pdeo) |
| return -ENOMEM; |
| |
| spin_lock(&pde->pde_unload_lock); |
| if (!pde->proc_fops) { |
| spin_unlock(&pde->pde_unload_lock); |
| kfree(pdeo); |
| return -ENOENT; |
| } |
| pde->pde_users++; |
| open = pde->proc_fops->open; |
| release = pde->proc_fops->release; |
| spin_unlock(&pde->pde_unload_lock); |
| |
| if (open) |
| rv = open(inode, file); |
| |
| spin_lock(&pde->pde_unload_lock); |
| if (rv == 0 && release) { |
| /* To know what to release. */ |
| pdeo->inode = inode; |
| pdeo->file = file; |
| /* Strictly for "too late" ->release in proc_reg_release(). */ |
| pdeo->release = release; |
| list_add(&pdeo->lh, &pde->pde_openers); |
| } else |
| kfree(pdeo); |
| __pde_users_dec(pde); |
| spin_unlock(&pde->pde_unload_lock); |
| return rv; |
| } |
| |
| static struct pde_opener *find_pde_opener(struct proc_dir_entry *pde, |
| struct inode *inode, struct file *file) |
| { |
| struct pde_opener *pdeo; |
| |
| list_for_each_entry(pdeo, &pde->pde_openers, lh) { |
| if (pdeo->inode == inode && pdeo->file == file) |
| return pdeo; |
| } |
| return NULL; |
| } |
| |
| static int proc_reg_release(struct inode *inode, struct file *file) |
| { |
| struct proc_dir_entry *pde = PDE(inode); |
| int rv = 0; |
| int (*release)(struct inode *, struct file *); |
| struct pde_opener *pdeo; |
| |
| spin_lock(&pde->pde_unload_lock); |
| pdeo = find_pde_opener(pde, inode, file); |
| if (!pde->proc_fops) { |
| /* |
| * Can't simply exit, __fput() will think that everything is OK, |
| * and move on to freeing struct file. remove_proc_entry() will |
| * find slacker in opener's list and will try to do non-trivial |
| * things with struct file. Therefore, remove opener from list. |
| * |
| * But if opener is removed from list, who will ->release it? |
| */ |
| if (pdeo) { |
| list_del(&pdeo->lh); |
| spin_unlock(&pde->pde_unload_lock); |
| rv = pdeo->release(inode, file); |
| kfree(pdeo); |
| } else |
| spin_unlock(&pde->pde_unload_lock); |
| return rv; |
| } |
| pde->pde_users++; |
| release = pde->proc_fops->release; |
| if (pdeo) { |
| list_del(&pdeo->lh); |
| kfree(pdeo); |
| } |
| spin_unlock(&pde->pde_unload_lock); |
| |
| if (release) |
| rv = release(inode, file); |
| |
| pde_users_dec(pde); |
| return rv; |
| } |
| |
| static const struct file_operations proc_reg_file_ops = { |
| .llseek = proc_reg_llseek, |
| .read = proc_reg_read, |
| .write = proc_reg_write, |
| .poll = proc_reg_poll, |
| .unlocked_ioctl = proc_reg_unlocked_ioctl, |
| #ifdef CONFIG_COMPAT |
| .compat_ioctl = proc_reg_compat_ioctl, |
| #endif |
| .mmap = proc_reg_mmap, |
| .open = proc_reg_open, |
| .release = proc_reg_release, |
| }; |
| |
| #ifdef CONFIG_COMPAT |
| static const struct file_operations proc_reg_file_ops_no_compat = { |
| .llseek = proc_reg_llseek, |
| .read = proc_reg_read, |
| .write = proc_reg_write, |
| .poll = proc_reg_poll, |
| .unlocked_ioctl = proc_reg_unlocked_ioctl, |
| .mmap = proc_reg_mmap, |
| .open = proc_reg_open, |
| .release = proc_reg_release, |
| }; |
| #endif |
| |
| struct inode *proc_get_inode(struct super_block *sb, struct proc_dir_entry *de) |
| { |
| struct inode * inode; |
| |
| inode = iget_locked(sb, de->low_ino); |
| if (!inode) |
| return NULL; |
| if (inode->i_state & I_NEW) { |
| inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME; |
| PROC_I(inode)->fd = 0; |
| PROC_I(inode)->pde = de; |
| |
| if (de->mode) { |
| inode->i_mode = de->mode; |
| inode->i_uid = de->uid; |
| inode->i_gid = de->gid; |
| } |
| if (de->size) |
| inode->i_size = de->size; |
| if (de->nlink) |
| set_nlink(inode, de->nlink); |
| if (de->proc_iops) |
| inode->i_op = de->proc_iops; |
| if (de->proc_fops) { |
| if (S_ISREG(inode->i_mode)) { |
| #ifdef CONFIG_COMPAT |
| if (!de->proc_fops->compat_ioctl) |
| inode->i_fop = |
| &proc_reg_file_ops_no_compat; |
| else |
| #endif |
| inode->i_fop = &proc_reg_file_ops; |
| } else { |
| inode->i_fop = de->proc_fops; |
| } |
| } |
| unlock_new_inode(inode); |
| } else |
| pde_put(de); |
| return inode; |
| } |
| |
| int proc_fill_super(struct super_block *s) |
| { |
| struct inode * root_inode; |
| |
| s->s_flags |= MS_NODIRATIME | MS_NOSUID | MS_NOEXEC; |
| s->s_blocksize = 1024; |
| s->s_blocksize_bits = 10; |
| s->s_magic = PROC_SUPER_MAGIC; |
| s->s_op = &proc_sops; |
| s->s_time_gran = 1; |
| |
| pde_get(&proc_root); |
| root_inode = proc_get_inode(s, &proc_root); |
| if (!root_inode) |
| goto out_no_root; |
| s->s_root = d_alloc_root(root_inode); |
| if (!s->s_root) { |
| iput(root_inode); |
| goto out_no_root; |
| } |
| return 0; |
| |
| out_no_root: |
| printk("proc_read_super: get root inode failed\n"); |
| pde_put(&proc_root); |
| return -ENOMEM; |
| } |