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 struct task_struct *tsk; 62 63 truncate_inode_pages(&inode->i_data, 0); 64 65 /* Let go of any associated process */ 66 tsk = PROC_I(inode)->task; 67 if (tsk) 68 put_task_struct(tsk); 69 70 /* Let go of any associated proc directory entry */ 71 de = PROC_I(inode)->pde; 72 if (de) { 73 if (de->owner) 74 module_put(de->owner); 75 de_put(de); 76 } 77 clear_inode(inode); 78 } 79 80 struct vfsmount *proc_mnt; 81 82 static void proc_read_inode(struct inode * inode) 83 { 84 inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME; 85 } 86 87 static kmem_cache_t * proc_inode_cachep; 88 89 static struct inode *proc_alloc_inode(struct super_block *sb) 90 { 91 struct proc_inode *ei; 92 struct inode *inode; 93 94 ei = (struct proc_inode *)kmem_cache_alloc(proc_inode_cachep, SLAB_KERNEL); 95 if (!ei) 96 return NULL; 97 ei->task = NULL; 98 ei->type = 0; 99 ei->op.proc_get_link = NULL; 100 ei->pde = NULL; 101 inode = &ei->vfs_inode; 102 inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME; 103 return inode; 104 } 105 106 static void proc_destroy_inode(struct inode *inode) 107 { 108 kmem_cache_free(proc_inode_cachep, PROC_I(inode)); 109 } 110 111 static void init_once(void * foo, kmem_cache_t * cachep, unsigned long flags) 112 { 113 struct proc_inode *ei = (struct proc_inode *) foo; 114 115 if ((flags & (SLAB_CTOR_VERIFY|SLAB_CTOR_CONSTRUCTOR)) == 116 SLAB_CTOR_CONSTRUCTOR) 117 inode_init_once(&ei->vfs_inode); 118 } 119 120 int __init proc_init_inodecache(void) 121 { 122 proc_inode_cachep = kmem_cache_create("proc_inode_cache", 123 sizeof(struct proc_inode), 124 0, SLAB_RECLAIM_ACCOUNT, 125 init_once, NULL); 126 if (proc_inode_cachep == NULL) 127 return -ENOMEM; 128 return 0; 129 } 130 131 static int proc_remount(struct super_block *sb, int *flags, char *data) 132 { 133 *flags |= MS_NODIRATIME; 134 return 0; 135 } 136 137 static struct super_operations proc_sops = { 138 .alloc_inode = proc_alloc_inode, 139 .destroy_inode = proc_destroy_inode, 140 .read_inode = proc_read_inode, 141 .drop_inode = generic_delete_inode, 142 .delete_inode = proc_delete_inode, 143 .statfs = simple_statfs, 144 .remount_fs = proc_remount, 145 }; 146 147 struct inode *proc_get_inode(struct super_block *sb, unsigned int ino, 148 struct proc_dir_entry *de) 149 { 150 struct inode * inode; 151 152 /* 153 * Increment the use count so the dir entry can't disappear. 154 */ 155 de_get(de); 156 157 WARN_ON(de && de->deleted); 158 159 if (de != NULL && !try_module_get(de->owner)) 160 goto out_mod; 161 162 inode = iget(sb, ino); 163 if (!inode) 164 goto out_ino; 165 166 PROC_I(inode)->pde = de; 167 if (de) { 168 if (de->mode) { 169 inode->i_mode = de->mode; 170 inode->i_uid = de->uid; 171 inode->i_gid = de->gid; 172 } 173 if (de->size) 174 inode->i_size = de->size; 175 if (de->nlink) 176 inode->i_nlink = de->nlink; 177 if (de->proc_iops) 178 inode->i_op = de->proc_iops; 179 if (de->proc_fops) 180 inode->i_fop = de->proc_fops; 181 } 182 183 return inode; 184 185 out_ino: 186 if (de != NULL) 187 module_put(de->owner); 188 out_mod: 189 de_put(de); 190 return NULL; 191 } 192 193 int proc_fill_super(struct super_block *s, void *data, int silent) 194 { 195 struct inode * root_inode; 196 197 s->s_flags |= MS_NODIRATIME; 198 s->s_blocksize = 1024; 199 s->s_blocksize_bits = 10; 200 s->s_magic = PROC_SUPER_MAGIC; 201 s->s_op = &proc_sops; 202 s->s_time_gran = 1; 203 204 root_inode = proc_get_inode(s, PROC_ROOT_INO, &proc_root); 205 if (!root_inode) 206 goto out_no_root; 207 /* 208 * Fixup the root inode's nlink value 209 */ 210 root_inode->i_nlink += nr_processes(); 211 root_inode->i_uid = 0; 212 root_inode->i_gid = 0; 213 s->s_root = d_alloc_root(root_inode); 214 if (!s->s_root) 215 goto out_no_root; 216 return 0; 217 218 out_no_root: 219 printk("proc_read_super: get root inode failed\n"); 220 iput(root_inode); 221 return -ENOMEM; 222 } 223 MODULE_LICENSE("GPL"); 224