diff options
| -rw-r--r-- | fs/debugfs/file.c | 157 | ||||
| -rw-r--r-- | fs/debugfs/inode.c | 70 | ||||
| -rw-r--r-- | fs/debugfs/internal.h | 6 | ||||
| -rw-r--r-- | include/linux/debugfs.h | 20 |
4 files changed, 226 insertions, 27 deletions
diff --git a/fs/debugfs/file.c b/fs/debugfs/file.c index 736ab3c988f2..6eb58a8ed03c 100644 --- a/fs/debugfs/file.c +++ b/fs/debugfs/file.c @@ -23,9 +23,12 @@ #include <linux/atomic.h> #include <linux/device.h> #include <linux/srcu.h> +#include <asm/poll.h> #include "internal.h" +struct poll_table_struct; + static ssize_t default_read_file(struct file *file, char __user *buf, size_t count, loff_t *ppos) { @@ -66,7 +69,7 @@ const struct file_operations debugfs_noop_file_operations = { * debugfs_use_file_start() must be followed by a matching call * to debugfs_use_file_finish(). */ -static int debugfs_use_file_start(const struct dentry *dentry, int *srcu_idx) +int debugfs_use_file_start(const struct dentry *dentry, int *srcu_idx) __acquires(&debugfs_srcu) { *srcu_idx = srcu_read_lock(&debugfs_srcu); @@ -75,6 +78,7 @@ static int debugfs_use_file_start(const struct dentry *dentry, int *srcu_idx) return -EIO; return 0; } +EXPORT_SYMBOL_GPL(debugfs_use_file_start); /** * debugfs_use_file_finish - mark the end of file data access @@ -85,10 +89,11 @@ static int debugfs_use_file_start(const struct dentry *dentry, int *srcu_idx) * debugfs_remove_recursive() blocked by a former call to * debugfs_use_file_start() to proceed and return to its caller. */ -static void debugfs_use_file_finish(int srcu_idx) __releases(&debugfs_srcu) +void debugfs_use_file_finish(int srcu_idx) __releases(&debugfs_srcu) { srcu_read_unlock(&debugfs_srcu, srcu_idx); } +EXPORT_SYMBOL_GPL(debugfs_use_file_finish); #define F_DENTRY(filp) ((filp)->f_path.dentry) @@ -131,6 +136,154 @@ const struct file_operations debugfs_open_proxy_file_operations = { .open = open_proxy_open, }; +#define PROTO(args...) args +#define ARGS(args...) args + +#define FULL_PROXY_FUNC(name, ret_type, filp, proto, args) \ +static ret_type full_proxy_ ## name(proto) \ +{ \ + const struct dentry *dentry = F_DENTRY(filp); \ + const struct file_operations *real_fops = \ + REAL_FOPS_DEREF(dentry); \ + int srcu_idx; \ + ret_type r; \ + \ + r = debugfs_use_file_start(dentry, &srcu_idx); \ + if (likely(!r)) \ + r = real_fops->name(args); \ + debugfs_use_file_finish(srcu_idx); \ + return r; \ +} + +FULL_PROXY_FUNC(llseek, loff_t, filp, + PROTO(struct file *filp, loff_t offset, int whence), + ARGS(filp, offset, whence)); + +FULL_PROXY_FUNC(read, ssize_t, filp, + PROTO(struct file *filp, char __user *buf, size_t size, + loff_t *ppos), + ARGS(filp, buf, size, ppos)); + +FULL_PROXY_FUNC(write, ssize_t, filp, + PROTO(struct file *filp, const char __user *buf, size_t size, + loff_t *ppos), + ARGS(filp, buf, size, ppos)); + +FULL_PROXY_FUNC(unlocked_ioctl, long, filp, + PROTO(struct file *filp, unsigned int cmd, unsigned long arg), + ARGS(filp, cmd, arg)); + +static unsigned int full_proxy_poll(struct file *filp, + struct poll_table_struct *wait) +{ + const struct dentry *dentry = F_DENTRY(filp); + const struct file_operations *real_fops = REAL_FOPS_DEREF(dentry); + int srcu_idx; + unsigned int r = 0; + + if (debugfs_use_file_start(dentry, &srcu_idx)) { + debugfs_use_file_finish(srcu_idx); + return POLLHUP; + } + + r = real_fops->poll(filp, wait); + debugfs_use_file_finish(srcu_idx); + return r; +} + +static int full_proxy_release(struct inode *inode, struct file *filp) +{ + const struct dentry *dentry = F_DENTRY(filp); + const struct file_operations *real_fops = REAL_FOPS_DEREF(dentry); + const struct file_operations *proxy_fops = filp->f_op; + int r = 0; + + /* + * We must not protect this against removal races here: the + * original releaser should be called unconditionally in order + * not to leak any resources. Releasers must not assume that + * ->i_private is still being meaningful here. + */ + if (real_fops->release) + r = real_fops->release(inode, filp); + + replace_fops(filp, d_inode(dentry)->i_fop); + kfree((void *)proxy_fops); + fops_put(real_fops); + return 0; +} + +static void __full_proxy_fops_init(struct file_operations *proxy_fops, + const struct file_operations *real_fops) +{ + proxy_fops->release = full_proxy_release; + if (real_fops->llseek) + proxy_fops->llseek = full_proxy_llseek; + if (real_fops->read) + proxy_fops->read = full_proxy_read; + if (real_fops->write) + proxy_fops->write = full_proxy_write; + if (real_fops->poll) + proxy_fops->poll = full_proxy_poll; + if (real_fops->unlocked_ioctl) + proxy_fops->unlocked_ioctl = full_proxy_unlocked_ioctl; +} + +static int full_proxy_open(struct inode *inode, struct file *filp) +{ + const struct dentry *dentry = F_DENTRY(filp); + const struct file_operations *real_fops = NULL; + struct file_operations *proxy_fops = NULL; + int srcu_idx, r; + + r = debugfs_use_file_start(dentry, &srcu_idx); + if (r) { + r = -ENOENT; + goto out; + } + + real_fops = REAL_FOPS_DEREF(dentry); + real_fops = fops_get(real_fops); + if (!real_fops) { + /* Huh? Module did not cleanup after itself at exit? */ + WARN(1, "debugfs file owner did not clean up at exit: %pd", + dentry); + r = -ENXIO; + goto out; + } + + proxy_fops = kzalloc(sizeof(*proxy_fops), GFP_KERNEL); + if (!proxy_fops) { + r = -ENOMEM; + goto free_proxy; + } + __full_proxy_fops_init(proxy_fops, real_fops); + replace_fops(filp, proxy_fops); + + if (real_fops->open) { + r = real_fops->open(inode, filp); + + if (filp->f_op != proxy_fops) { + /* No protection against file removal anymore. */ + WARN(1, "debugfs file owner replaced proxy fops: %pd", + dentry); + goto free_proxy; + } + } + + goto out; +free_proxy: + kfree(proxy_fops); + fops_put(real_fops); +out: + debugfs_use_file_finish(srcu_idx); + return r; +} + +const struct file_operations debugfs_full_proxy_file_operations = { + .open = full_proxy_open, +}; + static struct dentry *debugfs_create_mode(const char *name, umode_t mode, struct dentry *parent, void *value, const struct file_operations *fops, diff --git a/fs/debugfs/inode.c b/fs/debugfs/inode.c index 2905dd160575..136f269f01de 100644 --- a/fs/debugfs/inode.c +++ b/fs/debugfs/inode.c @@ -300,6 +300,37 @@ static struct dentry *end_creating(struct dentry *dentry) return dentry; } +static struct dentry *__debugfs_create_file(const char *name, umode_t mode, + struct dentry *parent, void *data, + const struct file_operations *proxy_fops, + const struct file_operations *real_fops) +{ + struct dentry *dentry; + struct inode *inode; + + if (!(mode & S_IFMT)) + mode |= S_IFREG; + BUG_ON(!S_ISREG(mode)); + dentry = start_creating(name, parent); + + if (IS_ERR(dentry)) + return NULL; + + inode = debugfs_get_inode(dentry->d_sb); + if (unlikely(!inode)) + return failed_creating(dentry); + + inode->i_mode = mode; + inode->i_private = data; + + inode->i_fop = proxy_fops; + dentry->d_fsdata = (void *)real_fops; + + d_instantiate(dentry, inode); + fsnotify_create(d_inode(dentry->d_parent), dentry); + return end_creating(dentry); +} + /** * debugfs_create_file - create a file in the debugfs filesystem * @name: a pointer to a string containing the name of the file to create. @@ -330,33 +361,24 @@ struct dentry *debugfs_create_file(const char *name, umode_t mode, struct dentry *parent, void *data, const struct file_operations *fops) { - struct dentry *dentry; - struct inode *inode; - - if (!(mode & S_IFMT)) - mode |= S_IFREG; - BUG_ON(!S_ISREG(mode)); - dentry = start_creating(name, parent); - - if (IS_ERR(dentry)) - return NULL; - - inode = debugfs_get_inode(dentry->d_sb); - if (unlikely(!inode)) - return failed_creating(dentry); - inode->i_mode = mode; - inode->i_private = data; + return __debugfs_create_file(name, mode, parent, data, + fops ? &debugfs_full_proxy_file_operations : + &debugfs_noop_file_operations, + fops); +} +EXPORT_SYMBOL_GPL(debugfs_create_file); - inode->i_fop = fops ? &debugfs_open_proxy_file_operations - : &debugfs_noop_file_operations; - dentry->d_fsdata = (void *)fops; +struct dentry *debugfs_create_file_unsafe(const char *name, umode_t mode, + struct dentry *parent, void *data, + const struct file_operations *fops) +{ - d_instantiate(dentry, inode); - fsnotify_create(d_inode(dentry->d_parent), dentry); - return end_creating(dentry); + return __debugfs_create_file(name, mode, parent, data, + fops ? &debugfs_open_proxy_file_operations : + &debugfs_noop_file_operations, + fops); } -EXPORT_SYMBOL_GPL(debugfs_create_file); /** * debugfs_create_file_size - create a file in the debugfs filesystem @@ -579,6 +601,7 @@ void debugfs_remove(struct dentry *dentry) inode_unlock(d_inode(parent)); if (!ret) simple_release_fs(&debugfs_mount, &debugfs_mount_count); + synchronize_srcu(&debugfs_srcu); } EXPORT_SYMBOL_GPL(debugfs_remove); @@ -657,6 +680,7 @@ void debugfs_remove_recursive(struct dentry *dentry) if (!__debugfs_remove(child, parent)) simple_release_fs(&debugfs_mount, &debugfs_mount_count); inode_unlock(d_inode(parent)); + synchronize_srcu(&debugfs_srcu); } EXPORT_SYMBOL_GPL(debugfs_remove_recursive); diff --git a/fs/debugfs/internal.h b/fs/debugfs/internal.h index c7aaa5cb6685..bba52634b995 100644 --- a/fs/debugfs/internal.h +++ b/fs/debugfs/internal.h @@ -13,12 +13,14 @@ #define _DEBUGFS_INTERNAL_H_ struct file_operations; -struct srcu_struct; /* declared over in file.c */ extern const struct file_operations debugfs_noop_file_operations; extern const struct file_operations debugfs_open_proxy_file_operations; +extern const struct file_operations debugfs_full_proxy_file_operations; -extern struct srcu_struct debugfs_srcu; +struct dentry *debugfs_create_file_unsafe(const char *name, umode_t mode, + struct dentry *parent, void *data, + const struct file_operations *fops); #endif /* _DEBUGFS_INTERNAL_H_ */ diff --git a/include/linux/debugfs.h b/include/linux/debugfs.h index fcafe2d389f9..a63e6ea3321c 100644 --- a/include/linux/debugfs.h +++ b/include/linux/debugfs.h @@ -19,9 +19,11 @@ #include <linux/seq_file.h> #include <linux/types.h> +#include <linux/compiler.h> struct device; struct file_operations; +struct srcu_struct; struct debugfs_blob_wrapper { void *data; @@ -41,6 +43,8 @@ struct debugfs_regset32 { extern struct dentry *arch_debugfs_dir; +extern struct srcu_struct debugfs_srcu; + #if defined(CONFIG_DEBUG_FS) struct dentry *debugfs_create_file(const char *name, umode_t mode, @@ -65,6 +69,11 @@ struct dentry *debugfs_create_automount(const char *name, void debugfs_remove(struct dentry *dentry); void debugfs_remove_recursive(struct dentry *dentry); +int debugfs_use_file_start(const struct dentry *dentry, int *srcu_idx) + __acquires(&debugfs_srcu); + +void debugfs_use_file_finish(int srcu_idx) __releases(&debugfs_srcu); + struct dentry *debugfs_rename(struct dentry *old_dir, struct dentry *old_dentry, struct dentry *new_dir, const char *new_name); @@ -173,6 +182,17 @@ static inline void debugfs_remove(struct dentry *dentry) static inline void debugfs_remove_recursive(struct dentry *dentry) { } +static inline int debugfs_use_file_start(const struct dentry *dentry, + int *srcu_idx) + __acquires(&debugfs_srcu) +{ + return 0; +} + +static inline void debugfs_use_file_finish(int srcu_idx) + __releases(&debugfs_srcu) +{ } + static inline struct dentry *debugfs_rename(struct dentry *old_dir, struct dentry *old_dentry, struct dentry *new_dir, char *new_name) { |