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 #include "internal.h" 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 62 truncate_inode_pages(&inode->i_data, 0); 63 64 /* Stop tracking associated processes */ 65 put_pid(PROC_I(inode)->pid); 66 67 /* Let go of any associated proc directory entry */ 68 de = PROC_I(inode)->pde; 69 if (de) { 70 if (de->owner) 71 module_put(de->owner); 72 de_put(de); 73 } 74 clear_inode(inode); 75 } 76 77 struct vfsmount *proc_mnt; 78 79 static void proc_read_inode(struct inode * inode) 80 { 81 inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME; 82 } 83 84 static kmem_cache_t * proc_inode_cachep; 85 86 static struct inode *proc_alloc_inode(struct super_block *sb) 87 { 88 struct proc_inode *ei; 89 struct inode *inode; 90 91 ei = (struct proc_inode *)kmem_cache_alloc(proc_inode_cachep, SLAB_KERNEL); 92 if (!ei) 93 return NULL; 94 ei->pid = NULL; 95 ei->fd = 0; 96 ei->op.proc_get_link = NULL; 97 ei->pde = NULL; 98 inode = &ei->vfs_inode; 99 inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME; 100 return inode; 101 } 102 103 static void proc_destroy_inode(struct inode *inode) 104 { 105 kmem_cache_free(proc_inode_cachep, PROC_I(inode)); 106 } 107 108 static void init_once(void * foo, kmem_cache_t * cachep, unsigned long flags) 109 { 110 struct proc_inode *ei = (struct proc_inode *) foo; 111 112 if ((flags & (SLAB_CTOR_VERIFY|SLAB_CTOR_CONSTRUCTOR)) == 113 SLAB_CTOR_CONSTRUCTOR) 114 inode_init_once(&ei->vfs_inode); 115 } 116 117 int __init proc_init_inodecache(void) 118 { 119 proc_inode_cachep = kmem_cache_create("proc_inode_cache", 120 sizeof(struct proc_inode), 121 0, (SLAB_RECLAIM_ACCOUNT| 122 SLAB_MEM_SPREAD), 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 if (de != NULL && !try_module_get(de->owner)) 158 goto out_mod; 159 160 inode = iget(sb, ino); 161 if (!inode) 162 goto out_ino; 163 164 PROC_I(inode)->pde = de; 165 if (de) { 166 if (de->mode) { 167 inode->i_mode = de->mode; 168 inode->i_uid = de->uid; 169 inode->i_gid = de->gid; 170 } 171 if (de->size) 172 inode->i_size = de->size; 173 if (de->nlink) 174 inode->i_nlink = de->nlink; 175 if (de->proc_iops) 176 inode->i_op = de->proc_iops; 177 if (de->proc_fops) 178 inode->i_fop = de->proc_fops; 179 } 180 181 return inode; 182 183 out_ino: 184 if (de != NULL) 185 module_put(de->owner); 186 out_mod: 187 de_put(de); 188 return NULL; 189 } 190 191 int proc_fill_super(struct super_block *s, void *data, int silent) 192 { 193 struct inode * root_inode; 194 195 s->s_flags |= MS_NODIRATIME; 196 s->s_blocksize = 1024; 197 s->s_blocksize_bits = 10; 198 s->s_magic = PROC_SUPER_MAGIC; 199 s->s_op = &proc_sops; 200 s->s_time_gran = 1; 201 202 root_inode = proc_get_inode(s, PROC_ROOT_INO, &proc_root); 203 if (!root_inode) 204 goto out_no_root; 205 root_inode->i_uid = 0; 206 root_inode->i_gid = 0; 207 s->s_root = d_alloc_root(root_inode); 208 if (!s->s_root) 209 goto out_no_root; 210 return 0; 211 212 out_no_root: 213 printk("proc_read_super: get root inode failed\n"); 214 iput(root_inode); 215 return -ENOMEM; 216 } 217 MODULE_LICENSE("GPL"); 218