1 /* 2 * linux/fs/proc/inode.c 3 * 4 * Copyright (C) 1991, 1992 Linus Torvalds 5 */ 6 7 #include <linux/time.h> 8 #include <linux/proc_fs.h> 9 #include <linux/kernel.h> 10 #include <linux/mm.h> 11 #include <linux/string.h> 12 #include <linux/stat.h> 13 #include <linux/file.h> 14 #include <linux/limits.h> 15 #include <linux/init.h> 16 #include <linux/module.h> 17 #include <linux/smp_lock.h> 18 19 #include <asm/system.h> 20 #include <asm/uaccess.h> 21 22 extern void free_proc_entry(struct proc_dir_entry *); 23 24 static inline struct proc_dir_entry * de_get(struct proc_dir_entry *de) 25 { 26 if (de) 27 atomic_inc(&de->count); 28 return de; 29 } 30 31 /* 32 * Decrements the use count and checks for deferred deletion. 33 */ 34 static void de_put(struct proc_dir_entry *de) 35 { 36 if (de) { 37 lock_kernel(); 38 if (!atomic_read(&de->count)) { 39 printk("de_put: entry %s already free!\n", de->name); 40 unlock_kernel(); 41 return; 42 } 43 44 if (atomic_dec_and_test(&de->count)) { 45 if (de->deleted) { 46 printk("de_put: deferred delete of %s\n", 47 de->name); 48 free_proc_entry(de); 49 } 50 } 51 unlock_kernel(); 52 } 53 } 54 55 /* 56 * Decrement the use count of the proc_dir_entry. 57 */ 58 static void proc_delete_inode(struct inode *inode) 59 { 60 struct proc_dir_entry *de; 61 struct task_struct *tsk; 62 63 /* Let go of any associated process */ 64 tsk = PROC_I(inode)->task; 65 if (tsk) 66 put_task_struct(tsk); 67 68 /* Let go of any associated proc directory entry */ 69 de = PROC_I(inode)->pde; 70 if (de) { 71 if (de->owner) 72 module_put(de->owner); 73 de_put(de); 74 } 75 clear_inode(inode); 76 } 77 78 struct vfsmount *proc_mnt; 79 80 static void proc_read_inode(struct inode * inode) 81 { 82 inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME; 83 } 84 85 static kmem_cache_t * proc_inode_cachep; 86 87 static struct inode *proc_alloc_inode(struct super_block *sb) 88 { 89 struct proc_inode *ei; 90 struct inode *inode; 91 92 ei = (struct proc_inode *)kmem_cache_alloc(proc_inode_cachep, SLAB_KERNEL); 93 if (!ei) 94 return NULL; 95 ei->task = NULL; 96 ei->type = 0; 97 ei->op.proc_get_link = NULL; 98 ei->pde = NULL; 99 inode = &ei->vfs_inode; 100 inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME; 101 return inode; 102 } 103 104 static void proc_destroy_inode(struct inode *inode) 105 { 106 kmem_cache_free(proc_inode_cachep, PROC_I(inode)); 107 } 108 109 static void init_once(void * foo, kmem_cache_t * cachep, unsigned long flags) 110 { 111 struct proc_inode *ei = (struct proc_inode *) foo; 112 113 if ((flags & (SLAB_CTOR_VERIFY|SLAB_CTOR_CONSTRUCTOR)) == 114 SLAB_CTOR_CONSTRUCTOR) 115 inode_init_once(&ei->vfs_inode); 116 } 117 118 int __init proc_init_inodecache(void) 119 { 120 proc_inode_cachep = kmem_cache_create("proc_inode_cache", 121 sizeof(struct proc_inode), 122 0, SLAB_RECLAIM_ACCOUNT, 123 init_once, NULL); 124 if (proc_inode_cachep == NULL) 125 return -ENOMEM; 126 return 0; 127 } 128 129 static int proc_remount(struct super_block *sb, int *flags, char *data) 130 { 131 *flags |= MS_NODIRATIME; 132 return 0; 133 } 134 135 static struct super_operations proc_sops = { 136 .alloc_inode = proc_alloc_inode, 137 .destroy_inode = proc_destroy_inode, 138 .read_inode = proc_read_inode, 139 .drop_inode = generic_delete_inode, 140 .delete_inode = proc_delete_inode, 141 .statfs = simple_statfs, 142 .remount_fs = proc_remount, 143 }; 144 145 struct inode *proc_get_inode(struct super_block *sb, unsigned int ino, 146 struct proc_dir_entry *de) 147 { 148 struct inode * inode; 149 150 /* 151 * Increment the use count so the dir entry can't disappear. 152 */ 153 de_get(de); 154 155 WARN_ON(de && de->deleted); 156 157 inode = iget(sb, ino); 158 if (!inode) 159 goto out_fail; 160 161 PROC_I(inode)->pde = de; 162 if (de) { 163 if (de->mode) { 164 inode->i_mode = de->mode; 165 inode->i_uid = de->uid; 166 inode->i_gid = de->gid; 167 } 168 if (de->size) 169 inode->i_size = de->size; 170 if (de->nlink) 171 inode->i_nlink = de->nlink; 172 if (!try_module_get(de->owner)) 173 goto out_fail; 174 if (de->proc_iops) 175 inode->i_op = de->proc_iops; 176 if (de->proc_fops) 177 inode->i_fop = de->proc_fops; 178 } 179 180 out: 181 return inode; 182 183 out_fail: 184 de_put(de); 185 goto out; 186 } 187 188 int proc_fill_super(struct super_block *s, void *data, int silent) 189 { 190 struct inode * root_inode; 191 192 s->s_flags |= MS_NODIRATIME; 193 s->s_blocksize = 1024; 194 s->s_blocksize_bits = 10; 195 s->s_magic = PROC_SUPER_MAGIC; 196 s->s_op = &proc_sops; 197 s->s_time_gran = 1; 198 199 root_inode = proc_get_inode(s, PROC_ROOT_INO, &proc_root); 200 if (!root_inode) 201 goto out_no_root; 202 /* 203 * Fixup the root inode's nlink value 204 */ 205 root_inode->i_nlink += nr_processes(); 206 root_inode->i_uid = 0; 207 root_inode->i_gid = 0; 208 s->s_root = d_alloc_root(root_inode); 209 if (!s->s_root) 210 goto out_no_root; 211 return 0; 212 213 out_no_root: 214 printk("proc_read_super: get root inode failed\n"); 215 iput(root_inode); 216 return -ENOMEM; 217 } 218 MODULE_LICENSE("GPL"); 219