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709 lines
17 KiB
709 lines
17 KiB
// SPDX-License-Identifier: GPL-2.0 |
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/* |
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* linux/fs/proc/inode.c |
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* |
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* Copyright (C) 1991, 1992 Linus Torvalds |
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*/ |
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|
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#include <linux/cache.h> |
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#include <linux/time.h> |
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#include <linux/proc_fs.h> |
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#include <linux/kernel.h> |
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#include <linux/pid_namespace.h> |
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#include <linux/mm.h> |
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#include <linux/string.h> |
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#include <linux/stat.h> |
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#include <linux/completion.h> |
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#include <linux/poll.h> |
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#include <linux/printk.h> |
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#include <linux/file.h> |
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#include <linux/limits.h> |
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#include <linux/init.h> |
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#include <linux/module.h> |
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#include <linux/sysctl.h> |
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#include <linux/seq_file.h> |
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#include <linux/slab.h> |
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#include <linux/mount.h> |
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#include <linux/bug.h> |
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#include <linux/uaccess.h> |
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#include "internal.h" |
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static void proc_evict_inode(struct inode *inode) |
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{ |
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struct proc_dir_entry *de; |
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struct ctl_table_header *head; |
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struct proc_inode *ei = PROC_I(inode); |
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truncate_inode_pages_final(&inode->i_data); |
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clear_inode(inode); |
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/* Stop tracking associated processes */ |
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if (ei->pid) { |
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proc_pid_evict_inode(ei); |
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ei->pid = NULL; |
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} |
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/* Let go of any associated proc directory entry */ |
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de = ei->pde; |
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if (de) { |
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pde_put(de); |
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ei->pde = NULL; |
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} |
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head = ei->sysctl; |
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if (head) { |
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RCU_INIT_POINTER(ei->sysctl, NULL); |
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proc_sys_evict_inode(inode, head); |
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} |
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} |
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static struct kmem_cache *proc_inode_cachep __ro_after_init; |
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static struct kmem_cache *pde_opener_cache __ro_after_init; |
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static struct inode *proc_alloc_inode(struct super_block *sb) |
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{ |
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struct proc_inode *ei; |
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ei = kmem_cache_alloc(proc_inode_cachep, GFP_KERNEL); |
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if (!ei) |
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return NULL; |
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ei->pid = NULL; |
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ei->fd = 0; |
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ei->op.proc_get_link = NULL; |
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ei->pde = NULL; |
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ei->sysctl = NULL; |
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ei->sysctl_entry = NULL; |
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INIT_HLIST_NODE(&ei->sibling_inodes); |
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ei->ns_ops = NULL; |
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return &ei->vfs_inode; |
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} |
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static void proc_free_inode(struct inode *inode) |
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{ |
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kmem_cache_free(proc_inode_cachep, PROC_I(inode)); |
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} |
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static void init_once(void *foo) |
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{ |
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struct proc_inode *ei = (struct proc_inode *) foo; |
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inode_init_once(&ei->vfs_inode); |
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} |
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void __init proc_init_kmemcache(void) |
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{ |
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proc_inode_cachep = kmem_cache_create("proc_inode_cache", |
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sizeof(struct proc_inode), |
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0, (SLAB_RECLAIM_ACCOUNT| |
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SLAB_MEM_SPREAD|SLAB_ACCOUNT| |
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SLAB_PANIC), |
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init_once); |
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pde_opener_cache = |
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kmem_cache_create("pde_opener", sizeof(struct pde_opener), 0, |
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SLAB_ACCOUNT|SLAB_PANIC, NULL); |
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proc_dir_entry_cache = kmem_cache_create_usercopy( |
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"proc_dir_entry", SIZEOF_PDE, 0, SLAB_PANIC, |
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offsetof(struct proc_dir_entry, inline_name), |
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SIZEOF_PDE_INLINE_NAME, NULL); |
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BUILD_BUG_ON(sizeof(struct proc_dir_entry) >= SIZEOF_PDE); |
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} |
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void proc_invalidate_siblings_dcache(struct hlist_head *inodes, spinlock_t *lock) |
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{ |
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struct inode *inode; |
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struct proc_inode *ei; |
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struct hlist_node *node; |
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struct super_block *old_sb = NULL; |
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rcu_read_lock(); |
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for (;;) { |
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struct super_block *sb; |
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node = hlist_first_rcu(inodes); |
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if (!node) |
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break; |
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ei = hlist_entry(node, struct proc_inode, sibling_inodes); |
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spin_lock(lock); |
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hlist_del_init_rcu(&ei->sibling_inodes); |
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spin_unlock(lock); |
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inode = &ei->vfs_inode; |
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sb = inode->i_sb; |
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if ((sb != old_sb) && !atomic_inc_not_zero(&sb->s_active)) |
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continue; |
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inode = igrab(inode); |
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rcu_read_unlock(); |
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if (sb != old_sb) { |
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if (old_sb) |
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deactivate_super(old_sb); |
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old_sb = sb; |
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} |
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if (unlikely(!inode)) { |
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rcu_read_lock(); |
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continue; |
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} |
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if (S_ISDIR(inode->i_mode)) { |
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struct dentry *dir = d_find_any_alias(inode); |
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if (dir) { |
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d_invalidate(dir); |
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dput(dir); |
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} |
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} else { |
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struct dentry *dentry; |
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while ((dentry = d_find_alias(inode))) { |
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d_invalidate(dentry); |
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dput(dentry); |
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} |
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} |
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iput(inode); |
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rcu_read_lock(); |
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} |
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rcu_read_unlock(); |
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if (old_sb) |
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deactivate_super(old_sb); |
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} |
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static inline const char *hidepid2str(enum proc_hidepid v) |
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{ |
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switch (v) { |
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case HIDEPID_OFF: return "off"; |
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case HIDEPID_NO_ACCESS: return "noaccess"; |
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case HIDEPID_INVISIBLE: return "invisible"; |
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case HIDEPID_NOT_PTRACEABLE: return "ptraceable"; |
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} |
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WARN_ONCE(1, "bad hide_pid value: %d\n", v); |
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return "unknown"; |
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} |
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static int proc_show_options(struct seq_file *seq, struct dentry *root) |
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{ |
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struct proc_fs_info *fs_info = proc_sb_info(root->d_sb); |
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if (!gid_eq(fs_info->pid_gid, GLOBAL_ROOT_GID)) |
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seq_printf(seq, ",gid=%u", from_kgid_munged(&init_user_ns, fs_info->pid_gid)); |
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if (fs_info->hide_pid != HIDEPID_OFF) |
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seq_printf(seq, ",hidepid=%s", hidepid2str(fs_info->hide_pid)); |
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if (fs_info->pidonly != PROC_PIDONLY_OFF) |
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seq_printf(seq, ",subset=pid"); |
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return 0; |
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} |
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const struct super_operations proc_sops = { |
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.alloc_inode = proc_alloc_inode, |
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.free_inode = proc_free_inode, |
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.drop_inode = generic_delete_inode, |
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.evict_inode = proc_evict_inode, |
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.statfs = simple_statfs, |
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.show_options = proc_show_options, |
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}; |
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enum {BIAS = -1U<<31}; |
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static inline int use_pde(struct proc_dir_entry *pde) |
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{ |
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return likely(atomic_inc_unless_negative(&pde->in_use)); |
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} |
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static void unuse_pde(struct proc_dir_entry *pde) |
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{ |
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if (unlikely(atomic_dec_return(&pde->in_use) == BIAS)) |
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complete(pde->pde_unload_completion); |
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} |
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/* pde is locked on entry, unlocked on exit */ |
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static void close_pdeo(struct proc_dir_entry *pde, struct pde_opener *pdeo) |
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__releases(&pde->pde_unload_lock) |
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{ |
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/* |
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* close() (proc_reg_release()) can't delete an entry and proceed: |
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* ->release hook needs to be available at the right moment. |
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* |
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* rmmod (remove_proc_entry() et al) can't delete an entry and proceed: |
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* "struct file" needs to be available at the right moment. |
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* |
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* Therefore, first process to enter this function does ->release() and |
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* signals its completion to the other process which does nothing. |
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*/ |
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if (pdeo->closing) { |
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/* somebody else is doing that, just wait */ |
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DECLARE_COMPLETION_ONSTACK(c); |
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pdeo->c = &c; |
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spin_unlock(&pde->pde_unload_lock); |
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wait_for_completion(&c); |
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} else { |
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struct file *file; |
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struct completion *c; |
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pdeo->closing = true; |
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spin_unlock(&pde->pde_unload_lock); |
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file = pdeo->file; |
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pde->proc_ops->proc_release(file_inode(file), file); |
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spin_lock(&pde->pde_unload_lock); |
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/* After ->release. */ |
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list_del(&pdeo->lh); |
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c = pdeo->c; |
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spin_unlock(&pde->pde_unload_lock); |
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if (unlikely(c)) |
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complete(c); |
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kmem_cache_free(pde_opener_cache, pdeo); |
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} |
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} |
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void proc_entry_rundown(struct proc_dir_entry *de) |
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{ |
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DECLARE_COMPLETION_ONSTACK(c); |
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/* Wait until all existing callers into module are done. */ |
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de->pde_unload_completion = &c; |
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if (atomic_add_return(BIAS, &de->in_use) != BIAS) |
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wait_for_completion(&c); |
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/* ->pde_openers list can't grow from now on. */ |
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spin_lock(&de->pde_unload_lock); |
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while (!list_empty(&de->pde_openers)) { |
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struct pde_opener *pdeo; |
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pdeo = list_first_entry(&de->pde_openers, struct pde_opener, lh); |
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close_pdeo(de, pdeo); |
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spin_lock(&de->pde_unload_lock); |
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} |
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spin_unlock(&de->pde_unload_lock); |
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} |
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static loff_t pde_lseek(struct proc_dir_entry *pde, struct file *file, loff_t offset, int whence) |
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{ |
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typeof_member(struct proc_ops, proc_lseek) lseek; |
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lseek = pde->proc_ops->proc_lseek; |
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if (!lseek) |
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lseek = default_llseek; |
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return lseek(file, offset, whence); |
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} |
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static loff_t proc_reg_llseek(struct file *file, loff_t offset, int whence) |
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{ |
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struct proc_dir_entry *pde = PDE(file_inode(file)); |
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loff_t rv = -EINVAL; |
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if (pde_is_permanent(pde)) { |
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return pde_lseek(pde, file, offset, whence); |
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} else if (use_pde(pde)) { |
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rv = pde_lseek(pde, file, offset, whence); |
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unuse_pde(pde); |
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} |
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return rv; |
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} |
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static ssize_t proc_reg_read_iter(struct kiocb *iocb, struct iov_iter *iter) |
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{ |
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struct proc_dir_entry *pde = PDE(file_inode(iocb->ki_filp)); |
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ssize_t ret; |
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if (pde_is_permanent(pde)) |
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return pde->proc_ops->proc_read_iter(iocb, iter); |
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if (!use_pde(pde)) |
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return -EIO; |
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ret = pde->proc_ops->proc_read_iter(iocb, iter); |
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unuse_pde(pde); |
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return ret; |
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} |
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static ssize_t pde_read(struct proc_dir_entry *pde, struct file *file, char __user *buf, size_t count, loff_t *ppos) |
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{ |
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typeof_member(struct proc_ops, proc_read) read; |
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read = pde->proc_ops->proc_read; |
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if (read) |
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return read(file, buf, count, ppos); |
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return -EIO; |
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} |
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static ssize_t proc_reg_read(struct file *file, char __user *buf, size_t count, loff_t *ppos) |
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{ |
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struct proc_dir_entry *pde = PDE(file_inode(file)); |
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ssize_t rv = -EIO; |
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if (pde_is_permanent(pde)) { |
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return pde_read(pde, file, buf, count, ppos); |
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} else if (use_pde(pde)) { |
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rv = pde_read(pde, file, buf, count, ppos); |
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unuse_pde(pde); |
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} |
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return rv; |
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} |
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static ssize_t pde_write(struct proc_dir_entry *pde, struct file *file, const char __user *buf, size_t count, loff_t *ppos) |
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{ |
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typeof_member(struct proc_ops, proc_write) write; |
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write = pde->proc_ops->proc_write; |
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if (write) |
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return write(file, buf, count, ppos); |
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return -EIO; |
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} |
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static ssize_t proc_reg_write(struct file *file, const char __user *buf, size_t count, loff_t *ppos) |
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{ |
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struct proc_dir_entry *pde = PDE(file_inode(file)); |
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ssize_t rv = -EIO; |
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if (pde_is_permanent(pde)) { |
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return pde_write(pde, file, buf, count, ppos); |
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} else if (use_pde(pde)) { |
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rv = pde_write(pde, file, buf, count, ppos); |
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unuse_pde(pde); |
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} |
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return rv; |
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} |
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static __poll_t pde_poll(struct proc_dir_entry *pde, struct file *file, struct poll_table_struct *pts) |
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{ |
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typeof_member(struct proc_ops, proc_poll) poll; |
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poll = pde->proc_ops->proc_poll; |
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if (poll) |
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return poll(file, pts); |
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return DEFAULT_POLLMASK; |
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} |
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static __poll_t proc_reg_poll(struct file *file, struct poll_table_struct *pts) |
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{ |
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struct proc_dir_entry *pde = PDE(file_inode(file)); |
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__poll_t rv = DEFAULT_POLLMASK; |
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if (pde_is_permanent(pde)) { |
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return pde_poll(pde, file, pts); |
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} else if (use_pde(pde)) { |
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rv = pde_poll(pde, file, pts); |
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unuse_pde(pde); |
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} |
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return rv; |
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} |
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static long pde_ioctl(struct proc_dir_entry *pde, struct file *file, unsigned int cmd, unsigned long arg) |
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{ |
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typeof_member(struct proc_ops, proc_ioctl) ioctl; |
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ioctl = pde->proc_ops->proc_ioctl; |
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if (ioctl) |
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return ioctl(file, cmd, arg); |
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return -ENOTTY; |
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} |
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static long proc_reg_unlocked_ioctl(struct file *file, unsigned int cmd, unsigned long arg) |
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{ |
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struct proc_dir_entry *pde = PDE(file_inode(file)); |
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long rv = -ENOTTY; |
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if (pde_is_permanent(pde)) { |
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return pde_ioctl(pde, file, cmd, arg); |
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} else if (use_pde(pde)) { |
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rv = pde_ioctl(pde, file, cmd, arg); |
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unuse_pde(pde); |
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} |
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return rv; |
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} |
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#ifdef CONFIG_COMPAT |
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static long pde_compat_ioctl(struct proc_dir_entry *pde, struct file *file, unsigned int cmd, unsigned long arg) |
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{ |
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typeof_member(struct proc_ops, proc_compat_ioctl) compat_ioctl; |
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compat_ioctl = pde->proc_ops->proc_compat_ioctl; |
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if (compat_ioctl) |
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return compat_ioctl(file, cmd, arg); |
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return -ENOTTY; |
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} |
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static long proc_reg_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg) |
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{ |
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struct proc_dir_entry *pde = PDE(file_inode(file)); |
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long rv = -ENOTTY; |
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if (pde_is_permanent(pde)) { |
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return pde_compat_ioctl(pde, file, cmd, arg); |
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} else if (use_pde(pde)) { |
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rv = pde_compat_ioctl(pde, file, cmd, arg); |
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unuse_pde(pde); |
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} |
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return rv; |
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} |
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#endif |
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static int pde_mmap(struct proc_dir_entry *pde, struct file *file, struct vm_area_struct *vma) |
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{ |
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typeof_member(struct proc_ops, proc_mmap) mmap; |
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mmap = pde->proc_ops->proc_mmap; |
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if (mmap) |
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return mmap(file, vma); |
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return -EIO; |
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} |
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static int proc_reg_mmap(struct file *file, struct vm_area_struct *vma) |
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{ |
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struct proc_dir_entry *pde = PDE(file_inode(file)); |
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int rv = -EIO; |
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if (pde_is_permanent(pde)) { |
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return pde_mmap(pde, file, vma); |
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} else if (use_pde(pde)) { |
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rv = pde_mmap(pde, file, vma); |
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unuse_pde(pde); |
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} |
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return rv; |
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} |
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static unsigned long |
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pde_get_unmapped_area(struct proc_dir_entry *pde, struct file *file, unsigned long orig_addr, |
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unsigned long len, unsigned long pgoff, |
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unsigned long flags) |
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{ |
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typeof_member(struct proc_ops, proc_get_unmapped_area) get_area; |
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get_area = pde->proc_ops->proc_get_unmapped_area; |
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#ifdef CONFIG_MMU |
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if (!get_area) |
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get_area = current->mm->get_unmapped_area; |
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#endif |
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if (get_area) |
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return get_area(file, orig_addr, len, pgoff, flags); |
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return orig_addr; |
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} |
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static unsigned long |
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proc_reg_get_unmapped_area(struct file *file, unsigned long orig_addr, |
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unsigned long len, unsigned long pgoff, |
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unsigned long flags) |
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{ |
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struct proc_dir_entry *pde = PDE(file_inode(file)); |
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unsigned long rv = -EIO; |
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if (pde_is_permanent(pde)) { |
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return pde_get_unmapped_area(pde, file, orig_addr, len, pgoff, flags); |
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} else if (use_pde(pde)) { |
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rv = pde_get_unmapped_area(pde, file, orig_addr, len, pgoff, flags); |
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unuse_pde(pde); |
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} |
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return rv; |
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} |
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static int proc_reg_open(struct inode *inode, struct file *file) |
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{ |
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struct proc_fs_info *fs_info = proc_sb_info(inode->i_sb); |
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struct proc_dir_entry *pde = PDE(inode); |
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int rv = 0; |
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typeof_member(struct proc_ops, proc_open) open; |
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typeof_member(struct proc_ops, proc_release) release; |
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struct pde_opener *pdeo; |
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if (pde_is_permanent(pde)) { |
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open = pde->proc_ops->proc_open; |
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if (open) |
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rv = open(inode, file); |
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return rv; |
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} |
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|
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if (fs_info->pidonly == PROC_PIDONLY_ON) |
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return -ENOENT; |
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|
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/* |
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* Ensure that |
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* 1) PDE's ->release hook will be called no matter what |
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* either normally by close()/->release, or forcefully by |
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* rmmod/remove_proc_entry. |
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* |
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* 2) rmmod isn't blocked by opening file in /proc and sitting on |
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* the descriptor (including "rmmod foo </proc/foo" scenario). |
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* |
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* Save every "struct file" with custom ->release hook. |
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*/ |
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if (!use_pde(pde)) |
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return -ENOENT; |
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release = pde->proc_ops->proc_release; |
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if (release) { |
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pdeo = kmem_cache_alloc(pde_opener_cache, GFP_KERNEL); |
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if (!pdeo) { |
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rv = -ENOMEM; |
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goto out_unuse; |
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} |
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} |
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|
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open = pde->proc_ops->proc_open; |
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if (open) |
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rv = open(inode, file); |
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|
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if (release) { |
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if (rv == 0) { |
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/* To know what to release. */ |
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pdeo->file = file; |
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pdeo->closing = false; |
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pdeo->c = NULL; |
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spin_lock(&pde->pde_unload_lock); |
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list_add(&pdeo->lh, &pde->pde_openers); |
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spin_unlock(&pde->pde_unload_lock); |
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} else |
|
kmem_cache_free(pde_opener_cache, pdeo); |
|
} |
|
|
|
out_unuse: |
|
unuse_pde(pde); |
|
return rv; |
|
} |
|
|
|
static int proc_reg_release(struct inode *inode, struct file *file) |
|
{ |
|
struct proc_dir_entry *pde = PDE(inode); |
|
struct pde_opener *pdeo; |
|
|
|
if (pde_is_permanent(pde)) { |
|
typeof_member(struct proc_ops, proc_release) release; |
|
|
|
release = pde->proc_ops->proc_release; |
|
if (release) { |
|
return release(inode, file); |
|
} |
|
return 0; |
|
} |
|
|
|
spin_lock(&pde->pde_unload_lock); |
|
list_for_each_entry(pdeo, &pde->pde_openers, lh) { |
|
if (pdeo->file == file) { |
|
close_pdeo(pde, pdeo); |
|
return 0; |
|
} |
|
} |
|
spin_unlock(&pde->pde_unload_lock); |
|
return 0; |
|
} |
|
|
|
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, |
|
.mmap = proc_reg_mmap, |
|
.get_unmapped_area = proc_reg_get_unmapped_area, |
|
.open = proc_reg_open, |
|
.release = proc_reg_release, |
|
}; |
|
|
|
static const struct file_operations proc_iter_file_ops = { |
|
.llseek = proc_reg_llseek, |
|
.read_iter = proc_reg_read_iter, |
|
.write = proc_reg_write, |
|
.splice_read = generic_file_splice_read, |
|
.poll = proc_reg_poll, |
|
.unlocked_ioctl = proc_reg_unlocked_ioctl, |
|
.mmap = proc_reg_mmap, |
|
.get_unmapped_area = proc_reg_get_unmapped_area, |
|
.open = proc_reg_open, |
|
.release = proc_reg_release, |
|
}; |
|
|
|
#ifdef CONFIG_COMPAT |
|
static const struct file_operations proc_reg_file_ops_compat = { |
|
.llseek = proc_reg_llseek, |
|
.read = proc_reg_read, |
|
.write = proc_reg_write, |
|
.poll = proc_reg_poll, |
|
.unlocked_ioctl = proc_reg_unlocked_ioctl, |
|
.compat_ioctl = proc_reg_compat_ioctl, |
|
.mmap = proc_reg_mmap, |
|
.get_unmapped_area = proc_reg_get_unmapped_area, |
|
.open = proc_reg_open, |
|
.release = proc_reg_release, |
|
}; |
|
|
|
static const struct file_operations proc_iter_file_ops_compat = { |
|
.llseek = proc_reg_llseek, |
|
.read_iter = proc_reg_read_iter, |
|
.splice_read = generic_file_splice_read, |
|
.write = proc_reg_write, |
|
.poll = proc_reg_poll, |
|
.unlocked_ioctl = proc_reg_unlocked_ioctl, |
|
.compat_ioctl = proc_reg_compat_ioctl, |
|
.mmap = proc_reg_mmap, |
|
.get_unmapped_area = proc_reg_get_unmapped_area, |
|
.open = proc_reg_open, |
|
.release = proc_reg_release, |
|
}; |
|
#endif |
|
|
|
static void proc_put_link(void *p) |
|
{ |
|
unuse_pde(p); |
|
} |
|
|
|
static const char *proc_get_link(struct dentry *dentry, |
|
struct inode *inode, |
|
struct delayed_call *done) |
|
{ |
|
struct proc_dir_entry *pde = PDE(inode); |
|
if (!use_pde(pde)) |
|
return ERR_PTR(-EINVAL); |
|
set_delayed_call(done, proc_put_link, pde); |
|
return pde->data; |
|
} |
|
|
|
const struct inode_operations proc_link_inode_operations = { |
|
.get_link = proc_get_link, |
|
}; |
|
|
|
struct inode *proc_get_inode(struct super_block *sb, struct proc_dir_entry *de) |
|
{ |
|
struct inode *inode = new_inode(sb); |
|
|
|
if (!inode) { |
|
pde_put(de); |
|
return NULL; |
|
} |
|
|
|
inode->i_ino = de->low_ino; |
|
inode->i_mtime = inode->i_atime = inode->i_ctime = current_time(inode); |
|
PROC_I(inode)->pde = de; |
|
if (is_empty_pde(de)) { |
|
make_empty_dir_inode(inode); |
|
return inode; |
|
} |
|
|
|
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 (S_ISREG(inode->i_mode)) { |
|
inode->i_op = de->proc_iops; |
|
if (de->proc_ops->proc_read_iter) |
|
inode->i_fop = &proc_iter_file_ops; |
|
else |
|
inode->i_fop = &proc_reg_file_ops; |
|
#ifdef CONFIG_COMPAT |
|
if (de->proc_ops->proc_compat_ioctl) { |
|
if (de->proc_ops->proc_read_iter) |
|
inode->i_fop = &proc_iter_file_ops_compat; |
|
else |
|
inode->i_fop = &proc_reg_file_ops_compat; |
|
} |
|
#endif |
|
} else if (S_ISDIR(inode->i_mode)) { |
|
inode->i_op = de->proc_iops; |
|
inode->i_fop = de->proc_dir_ops; |
|
} else if (S_ISLNK(inode->i_mode)) { |
|
inode->i_op = de->proc_iops; |
|
inode->i_fop = NULL; |
|
} else { |
|
BUG(); |
|
} |
|
return inode; |
|
}
|
|
|