diff options
| -rw-r--r-- | fs/proc/generic.c | 32 | ||||
| -rw-r--r-- | fs/proc/inode.c | 254 | ||||
| -rw-r--r-- | include/linux/proc_fs.h | 13 |
3 files changed, 296 insertions, 3 deletions
diff --git a/fs/proc/generic.c b/fs/proc/generic.c index 8a40e15f5ec..4f8e53568b2 100644 --- a/fs/proc/generic.c +++ b/fs/proc/generic.c @@ -20,6 +20,7 @@ #include <linux/namei.h> #include <linux/bitops.h> #include <linux/spinlock.h> +#include <linux/completion.h> #include <asm/uaccess.h> #include "internal.h" @@ -613,6 +614,9 @@ static struct proc_dir_entry *proc_create(struct proc_dir_entry **parent, ent->namelen = len; ent->mode = mode; ent->nlink = nlink; + ent->pde_users = 0; + spin_lock_init(&ent->pde_unload_lock); + ent->pde_unload_completion = NULL; out: return ent; } @@ -734,9 +738,35 @@ void remove_proc_entry(const char *name, struct proc_dir_entry *parent) de = *p; *p = de->next; de->next = NULL; + + spin_lock(&de->pde_unload_lock); + /* + * Stop accepting new callers into module. If you're + * dynamically allocating ->proc_fops, save a pointer somewhere. + */ + de->proc_fops = NULL; + /* Wait until all existing callers into module are done. */ + if (de->pde_users > 0) { + DECLARE_COMPLETION_ONSTACK(c); + + if (!de->pde_unload_completion) + de->pde_unload_completion = &c; + + spin_unlock(&de->pde_unload_lock); + spin_unlock(&proc_subdir_lock); + + wait_for_completion(de->pde_unload_completion); + + spin_lock(&proc_subdir_lock); + goto continue_removing; + } + spin_unlock(&de->pde_unload_lock); + +continue_removing: if (S_ISDIR(de->mode)) parent->nlink--; - proc_kill_inodes(de); + if (!S_ISREG(de->mode)) + proc_kill_inodes(de); de->nlink = 0; WARN_ON(de->subdir); if (!atomic_read(&de->count)) diff --git a/fs/proc/inode.c b/fs/proc/inode.c index d5ce65c68d7..dd28e86ab42 100644 --- a/fs/proc/inode.c +++ b/fs/proc/inode.c @@ -10,6 +10,7 @@ #include <linux/mm.h> #include <linux/string.h> #include <linux/stat.h> +#include <linux/completion.h> #include <linux/file.h> #include <linux/limits.h> #include <linux/init.h> @@ -140,6 +141,251 @@ static const struct super_operations proc_sops = { .remount_fs = proc_remount, }; +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); + spin_unlock(&pde->pde_unload_lock); +} + +static loff_t proc_reg_llseek(struct file *file, loff_t offset, int whence) +{ + struct proc_dir_entry *pde = PDE(file->f_path.dentry->d_inode); + loff_t rv = -EINVAL; + loff_t (*llseek)(struct file *, loff_t, int); + + spin_lock(&pde->pde_unload_lock); + /* + * remove_proc_entry() is going to delete PDE (as part of module + * cleanup sequence). No new callers into module allowed. + */ + if (!pde->proc_fops) { + spin_unlock(&pde->pde_unload_lock); + return rv; + } + /* + * Bump refcount so that remove_proc_entry will wail for ->llseek to + * complete. + */ + pde->pde_users++; + /* + * Save function pointer under lock, to protect against ->proc_fops + * NULL'ifying right after ->pde_unload_lock is dropped. + */ + llseek = pde->proc_fops->llseek; + spin_unlock(&pde->pde_unload_lock); + + if (!llseek) + llseek = default_llseek; + rv = llseek(file, offset, whence); + + pde_users_dec(pde); + return rv; +} + +static ssize_t proc_reg_read(struct file *file, char __user *buf, size_t count, loff_t *ppos) +{ + struct proc_dir_entry *pde = PDE(file->f_path.dentry->d_inode); + ssize_t rv = -EIO; + ssize_t (*read)(struct file *, char __user *, size_t, loff_t *); + + spin_lock(&pde->pde_unload_lock); + if (!pde->proc_fops) { + spin_unlock(&pde->pde_unload_lock); + return rv; + } + pde->pde_users++; + read = pde->proc_fops->read; + spin_unlock(&pde->pde_unload_lock); + + if (read) + rv = read(file, buf, count, ppos); + + pde_users_dec(pde); + return rv; +} + +static ssize_t proc_reg_write(struct file *file, const char __user *buf, size_t count, loff_t *ppos) +{ + struct proc_dir_entry *pde = PDE(file->f_path.dentry->d_inode); + ssize_t rv = -EIO; + ssize_t (*write)(struct file *, const char __user *, size_t, loff_t *); + + spin_lock(&pde->pde_unload_lock); + if (!pde->proc_fops) { + spin_unlock(&pde->pde_unload_lock); + return rv; + } + pde->pde_users++; + write = pde->proc_fops->write; + spin_unlock(&pde->pde_unload_lock); + + if (write) + rv = write(file, buf, count, ppos); + + pde_users_dec(pde); + return rv; +} + +static unsigned int proc_reg_poll(struct file *file, struct poll_table_struct *pts) +{ + struct proc_dir_entry *pde = PDE(file->f_path.dentry->d_inode); + unsigned int rv = 0; + unsigned int (*poll)(struct file *, struct poll_table_struct *); + + spin_lock(&pde->pde_unload_lock); + if (!pde->proc_fops) { + spin_unlock(&pde->pde_unload_lock); + return rv; + } + pde->pde_users++; + poll = pde->proc_fops->poll; + spin_unlock(&pde->pde_unload_lock); + + if (poll) + rv = poll(file, pts); + + pde_users_dec(pde); + return rv; +} + +static long proc_reg_unlocked_ioctl(struct file *file, unsigned int cmd, unsigned long arg) +{ + struct proc_dir_entry *pde = PDE(file->f_path.dentry->d_inode); + long rv = -ENOTTY; + long (*unlocked_ioctl)(struct file *, unsigned int, unsigned long); + int (*ioctl)(struct inode *, struct file *, unsigned int, unsigned long); + + spin_lock(&pde->pde_unload_lock); + if (!pde->proc_fops) { + spin_unlock(&pde->pde_unload_lock); + return rv; + } + pde->pde_users++; + unlocked_ioctl = pde->proc_fops->unlocked_ioctl; + ioctl = pde->proc_fops->ioctl; + spin_unlock(&pde->pde_unload_lock); + + if (unlocked_ioctl) { + rv = unlocked_ioctl(file, cmd, arg); + if (rv == -ENOIOCTLCMD) + rv = -EINVAL; + } else if (ioctl) { + lock_kernel(); + rv = ioctl(file->f_path.dentry->d_inode, file, cmd, arg); + unlock_kernel(); + } + + pde_users_dec(pde); + return rv; +} + +#ifdef CONFIG_COMPAT +static long proc_reg_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg) +{ + struct proc_dir_entry *pde = PDE(file->f_path.dentry->d_inode); + long rv = -ENOTTY; + long (*compat_ioctl)(struct file *, unsigned int, unsigned long); + + spin_lock(&pde->pde_unload_lock); + if (!pde->proc_fops) { + spin_unlock(&pde->pde_unload_lock); + return rv; + } + pde->pde_users++; + compat_ioctl = pde->proc_fops->compat_ioctl; + spin_unlock(&pde->pde_unload_lock); + + if (compat_ioctl) + rv = compat_ioctl(file, cmd, arg); + + pde_users_dec(pde); + return rv; +} +#endif + +static int proc_reg_mmap(struct file *file, struct vm_area_struct *vma) +{ + struct proc_dir_entry *pde = PDE(file->f_path.dentry->d_inode); + int rv = -EIO; + int (*mmap)(struct file *, struct vm_area_struct *); + + spin_lock(&pde->pde_unload_lock); + if (!pde->proc_fops) { + spin_unlock(&pde->pde_unload_lock); + return rv; + } + pde->pde_users++; + mmap = pde->proc_fops->mmap; + spin_unlock(&pde->pde_unload_lock); + + if (mmap) + rv = mmap(file, vma); + + pde_users_dec(pde); + return rv; +} + +static int proc_reg_open(struct inode *inode, struct file *file) +{ + struct proc_dir_entry *pde = PDE(inode); + int rv = 0; + int (*open)(struct inode *, struct file *); + + spin_lock(&pde->pde_unload_lock); + if (!pde->proc_fops) { + spin_unlock(&pde->pde_unload_lock); + return rv; + } + pde->pde_users++; + open = pde->proc_fops->open; + spin_unlock(&pde->pde_unload_lock); + + if (open) + rv = open(inode, file); + + pde_users_dec(pde); + return rv; +} + +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 *); + + spin_lock(&pde->pde_unload_lock); + if (!pde->proc_fops) { + spin_unlock(&pde->pde_unload_lock); + return rv; + } + pde->pde_users++; + release = pde->proc_fops->release; + spin_unlock(&pde->pde_unload_lock); + + if (release) + rv = release(inode, file); + + pde_users_dec(pde); + return rv; +} + +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, +#ifdef CONFIG_COMPAT + .compat_ioctl = proc_reg_compat_ioctl, +#endif + .mmap = proc_reg_mmap, + .open = proc_reg_open, + .release = proc_reg_release, +}; + struct inode *proc_get_inode(struct super_block *sb, unsigned int ino, struct proc_dir_entry *de) { @@ -166,8 +412,12 @@ struct inode *proc_get_inode(struct super_block *sb, unsigned int ino, inode->i_nlink = de->nlink; if (de->proc_iops) inode->i_op = de->proc_iops; - if (de->proc_fops) - inode->i_fop = de->proc_fops; + if (de->proc_fops) { + if (S_ISREG(inode->i_mode)) + inode->i_fop = &proc_reg_file_ops; + else + inode->i_fop = de->proc_fops; + } } return inode; diff --git a/include/linux/proc_fs.h b/include/linux/proc_fs.h index 3469f96bc8b..28e3664fdf1 100644 --- a/include/linux/proc_fs.h +++ b/include/linux/proc_fs.h @@ -7,6 +7,8 @@ #include <linux/magic.h> #include <asm/atomic.h> +struct completion; + /* * The proc filesystem constants/structures */ @@ -56,6 +58,14 @@ struct proc_dir_entry { gid_t gid; loff_t size; const struct inode_operations *proc_iops; + /* + * NULL ->proc_fops means "PDE is going away RSN" or + * "PDE is just created". In either case, e.g. ->read_proc won't be + * called because it's too late or too early, respectively. + * + * If you're allocating ->proc_fops dynamically, save a pointer + * somewhere. + */ const struct file_operations *proc_fops; get_info_t *get_info; struct module *owner; @@ -66,6 +76,9 @@ struct proc_dir_entry { atomic_t count; /* use count */ int deleted; /* delete flag */ void *set; + int pde_users; /* number of callers into module in progress */ + spinlock_t pde_unload_lock; /* proc_fops checks and pde_users bumps */ + struct completion *pde_unload_completion; }; struct kcore_list { |