#include <linux/init.h>
#include <linux/module.h>
#include <linux/smp_lock.h>
+#include <linux/sysctl.h>
#include <asm/system.h>
#include <asm/uaccess.h>
struct proc_dir_entry *de_get(struct proc_dir_entry *de)
{
- if (de)
- atomic_inc(&de->count);
+ atomic_inc(&de->count);
return de;
}
*/
void de_put(struct proc_dir_entry *de)
{
- if (de) {
- lock_kernel();
- if (!atomic_read(&de->count)) {
- printk("de_put: entry %s already free!\n", de->name);
- unlock_kernel();
- return;
- }
-
- if (atomic_dec_and_test(&de->count))
- free_proc_entry(de);
+ lock_kernel();
+ if (!atomic_read(&de->count)) {
+ printk("de_put: entry %s already free!\n", de->name);
unlock_kernel();
+ return;
}
+
+ if (atomic_dec_and_test(&de->count))
+ free_proc_entry(de);
+ unlock_kernel();
}
/*
module_put(de->owner);
de_put(de);
}
+ if (PROC_I(inode)->sysctl)
+ sysctl_head_put(PROC_I(inode)->sysctl);
clear_inode(inode);
}
struct vfsmount *proc_mnt;
-static void proc_read_inode(struct inode * inode)
-{
- inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME;
-}
-
static struct kmem_cache * proc_inode_cachep;
static struct inode *proc_alloc_inode(struct super_block *sb)
ei->fd = 0;
ei->op.proc_get_link = NULL;
ei->pde = NULL;
+ ei->sysctl = NULL;
+ ei->sysctl_entry = NULL;
inode = &ei->vfs_inode;
inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME;
return inode;
kmem_cache_free(proc_inode_cachep, PROC_I(inode));
}
-static void init_once(struct kmem_cache * cachep, void *foo)
+static void init_once(void *foo)
{
struct proc_inode *ei = (struct proc_inode *) foo;
return 0;
}
-static int proc_remount(struct super_block *sb, int *flags, char *data)
-{
- *flags |= MS_NODIRATIME;
- return 0;
-}
-
static const struct super_operations proc_sops = {
.alloc_inode = proc_alloc_inode,
.destroy_inode = proc_destroy_inode,
- .read_inode = proc_read_inode,
.drop_inode = generic_delete_inode,
.delete_inode = proc_delete_inode,
.statfs = simple_statfs,
- .remount_fs = proc_remount,
};
-static void pde_users_dec(struct proc_dir_entry *pde)
+static void __pde_users_dec(struct proc_dir_entry *pde)
{
- spin_lock(&pde->pde_unload_lock);
pde->pde_users--;
if (pde->pde_unload_completion && pde->pde_users == 0)
complete(pde->pde_unload_completion);
+}
+
+static 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);
}
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 rv;
}
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);
- pde_users_dec(pde);
+ 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) {
- spin_unlock(&pde->pde_unload_lock);
+ /*
+ * 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)
{
struct inode * inode;
- if (de != NULL && !try_module_get(de->owner))
+ if (!try_module_get(de->owner))
goto out_mod;
- inode = iget(sb, ino);
+ inode = iget_locked(sb, ino);
if (!inode)
goto out_ino;
+ 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;
- PROC_I(inode)->fd = 0;
- PROC_I(inode)->pde = de;
- if (de) {
if (de->mode) {
inode->i_mode = de->mode;
inode->i_uid = de->uid;
else
#endif
inode->i_fop = &proc_reg_file_ops;
- }
- else
+ } else {
inode->i_fop = de->proc_fops;
+ }
}
- }
-
+ unlock_new_inode(inode);
+ } else
+ module_put(de->owner);
return inode;
out_ino:
- if (de != NULL)
- module_put(de->owner);
+ module_put(de->owner);
out_mod:
return NULL;
}
de_put(&proc_root);
return -ENOMEM;
}
-MODULE_LICENSE("GPL");