// SPDX-License-Identifier: GPL-2.0/* * file.c - part of debugfs, a tiny little debug file system * * Copyright (C) 2004 Greg Kroah-Hartman <greg@kroah.com> * Copyright (C) 2004 IBM Inc. * * debugfs is for people to use instead of /proc or /sys. * See Documentation/filesystems/ for more details. */ #include <linux/module.h>#include <linux/fs.h>#include <linux/seq_file.h>#include <linux/pagemap.h>#include <linux/debugfs.h>#include <linux/io.h>#include <linux/slab.h>#include <linux/atomic.h>#include <linux/device.h>#include <linux/pm_runtime.h>#include <linux/poll.h>#include <linux/security.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){ return 0;} static ssize_t default_write_file(struct file *file, const char __user *buf, size_t count, loff_t *ppos){ return count;} const struct file_operations debugfs_noop_file_operations = { .read = default_read_file, .write = default_write_file, .open = simple_open, .llseek = noop_llseek,}; #define F_DENTRY(filp) ((filp)->f_path.dentry) const struct file_operations *debugfs_real_fops(const struct file *filp){ struct debugfs_fsdata *fsd = F_DENTRY(filp)->d_fsdata; if ((unsigned long)fsd & DEBUGFS_FSDATA_IS_REAL_FOPS_BIT) { /* * Urgh, we've been called w/o a protecting * debugfs_file_get(). */ WARN_ON(1); return NULL; } return fsd->real_fops;}EXPORT_SYMBOL_GPL(debugfs_real_fops); enum dbgfs_get_mode { DBGFS_GET_ALREADY, DBGFS_GET_REGULAR, DBGFS_GET_SHORT,}; static int __debugfs_file_get(struct dentry *dentry, enum dbgfs_get_mode mode){ struct debugfs_fsdata *fsd; void *d_fsd; /* * This could only happen if some debugfs user erroneously calls * debugfs_file_get() on a dentry that isn't even a file, let * them know about it. */ if (WARN_ON(!d_is_reg(dentry))) return -EINVAL; d_fsd = READ_ONCE(dentry->d_fsdata); if (!((unsigned long)d_fsd & DEBUGFS_FSDATA_IS_REAL_FOPS_BIT)) { fsd = d_fsd; } else { if (WARN_ON(mode == DBGFS_GET_ALREADY)) return -EINVAL; fsd = kmalloc(sizeof(*fsd), GFP_KERNEL); if (!fsd) return -ENOMEM; if (mode == DBGFS_GET_SHORT) { fsd->real_fops = NULL; fsd->short_fops = (void *)((unsigned long)d_fsd & ~DEBUGFS_FSDATA_IS_REAL_FOPS_BIT); } else { fsd->real_fops = (void *)((unsigned long)d_fsd & ~DEBUGFS_FSDATA_IS_REAL_FOPS_BIT); fsd->short_fops = NULL; } refcount_set(&fsd->active_users, 1); init_completion(&fsd->active_users_drained); INIT_LIST_HEAD(&fsd->cancellations); mutex_init(&fsd->cancellations_mtx); if (cmpxchg(&dentry->d_fsdata, d_fsd, fsd) != d_fsd) { mutex_destroy(&fsd->cancellations_mtx); kfree(fsd); fsd = READ_ONCE(dentry->d_fsdata); } } /* * In case of a successful cmpxchg() above, this check is * strictly necessary and must follow it, see the comment in * __debugfs_remove_file(). * OTOH, if the cmpxchg() hasn't been executed or wasn't * successful, this serves the purpose of not starving * removers. */ if (d_unlinked(dentry)) return -EIO; if (!refcount_inc_not_zero(&fsd->active_users)) return -EIO; return 0;} /** * debugfs_file_get - mark the beginning of file data access * @dentry: the dentry object whose data is being accessed. * * Up to a matching call to debugfs_file_put(), any successive call * into the file removing functions debugfs_remove() and * debugfs_remove_recursive() will block. Since associated private * file data may only get freed after a successful return of any of * the removal functions, you may safely access it after a successful * call to debugfs_file_get() without worrying about lifetime issues. * * If -%EIO is returned, the file has already been removed and thus, * it is not safe to access any of its data. If, on the other hand, * it is allowed to access the file data, zero is returned. */int debugfs_file_get(struct dentry *dentry){ return __debugfs_file_get(dentry, DBGFS_GET_ALREADY);}EXPORT_SYMBOL_GPL(debugfs_file_get); /** * debugfs_file_put - mark the end of file data access * @dentry: the dentry object formerly passed to * debugfs_file_get(). * * Allow any ongoing concurrent call into debugfs_remove() or * debugfs_remove_recursive() blocked by a former call to * debugfs_file_get() to proceed and return to its caller. */void debugfs_file_put(struct dentry *dentry){ struct debugfs_fsdata *fsd = READ_ONCE(dentry->d_fsdata); if (refcount_dec_and_test(&fsd->active_users)) complete(&fsd->active_users_drained);}EXPORT_SYMBOL_GPL(debugfs_file_put); /** * debugfs_enter_cancellation - enter a debugfs cancellation * @file: the file being accessed * @cancellation: the cancellation object, the cancel callback * inside of it must be initialized * * When a debugfs file is removed it needs to wait for all active * operations to complete. However, the operation itself may need * to wait for hardware or completion of some asynchronous process * or similar. As such, it may need to be cancelled to avoid long * waits or even deadlocks. * * This function can be used inside a debugfs handler that may * need to be cancelled. As soon as this function is called, the * cancellation's 'cancel' callback may be called, at which point * the caller should proceed to call debugfs_leave_cancellation() * and leave the debugfs handler function as soon as possible. * Note that the 'cancel' callback is only ever called in the * context of some kind of debugfs_remove(). * * This function must be paired with debugfs_leave_cancellation(). */void debugfs_enter_cancellation(struct file *file, struct debugfs_cancellation *cancellation){ struct debugfs_fsdata *fsd; struct dentry *dentry = F_DENTRY(file); INIT_LIST_HEAD(&cancellation->list); if (WARN_ON(!d_is_reg(dentry))) return; if (WARN_ON(!cancellation->cancel)) return; fsd = READ_ONCE(dentry->d_fsdata); if (WARN_ON(!fsd || ((unsigned long)fsd & DEBUGFS_FSDATA_IS_REAL_FOPS_BIT))) return; mutex_lock(&fsd->cancellations_mtx); list_add(&cancellation->list, &fsd->cancellations); mutex_unlock(&fsd->cancellations_mtx); /* if we're already removing wake it up to cancel */ if (d_unlinked(dentry)) complete(&fsd->active_users_drained);}EXPORT_SYMBOL_GPL(debugfs_enter_cancellation); /** * debugfs_leave_cancellation - leave cancellation section * @file: the file being accessed * @cancellation: the cancellation previously registered with * debugfs_enter_cancellation() * * See the documentation of debugfs_enter_cancellation(). */void debugfs_leave_cancellation(struct file *file, struct debugfs_cancellation *cancellation){ struct debugfs_fsdata *fsd; struct dentry *dentry = F_DENTRY(file); if (WARN_ON(!d_is_reg(dentry))) return; fsd = READ_ONCE(dentry->d_fsdata); if (WARN_ON(!fsd || ((unsigned long)fsd & DEBUGFS_FSDATA_IS_REAL_FOPS_BIT))) return; mutex_lock(&fsd->cancellations_mtx); if (!list_empty(&cancellation->list)) list_del(&cancellation->list); mutex_unlock(&fsd->cancellations_mtx);}EXPORT_SYMBOL_GPL(debugfs_leave_cancellation); /* * Only permit access to world-readable files when the kernel is locked down. * We also need to exclude any file that has ways to write or alter it as root * can bypass the permissions check. */static int debugfs_locked_down(struct inode *inode, struct file *filp, const struct file_operations *real_fops){ if ((inode->i_mode & 07777 & ~0444) == 0 && !(filp->f_mode & FMODE_WRITE) && (!real_fops || (!real_fops->unlocked_ioctl && !real_fops->compat_ioctl && !real_fops->mmap))) return 0; if (security_locked_down(LOCKDOWN_DEBUGFS)) return -EPERM; return 0;} static int open_proxy_open(struct inode *inode, struct file *filp){ struct dentry *dentry = F_DENTRY(filp); const struct file_operations *real_fops = NULL; int r; r = __debugfs_file_get(dentry, DBGFS_GET_REGULAR); if (r) return r == -EIO ? -ENOENT : r; real_fops = debugfs_real_fops(filp); r = debugfs_locked_down(inode, filp, real_fops); if (r) goto out; if (!fops_get(real_fops)) {#ifdef CONFIG_MODULES if (real_fops->owner && real_fops->owner->state == MODULE_STATE_GOING) { r = -ENXIO; goto out; }#endif /* Huh? Module did not clean up after itself at exit? */ WARN(1, "debugfs file owner did not clean up at exit: %pd", dentry); r = -ENXIO; goto out; } replace_fops(filp, real_fops); if (real_fops->open) r = real_fops->open(inode, filp); out: debugfs_file_put(dentry); return r;} 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) \{ \ struct dentry *dentry = F_DENTRY(filp); \ const struct file_operations *real_fops; \ ret_type r; \ \ r = debugfs_file_get(dentry); \ if (unlikely(r)) \ return r; \ real_fops = debugfs_real_fops(filp); \ r = real_fops->name(args); \ debugfs_file_put(dentry); \ return r; \} #define FULL_PROXY_FUNC_BOTH(name, ret_type, filp, proto, args) \static ret_type full_proxy_ ## name(proto) \{ \ struct dentry *dentry = F_DENTRY(filp); \ struct debugfs_fsdata *fsd; \ ret_type r; \ \ r = debugfs_file_get(dentry); \ if (unlikely(r)) \ return r; \ fsd = dentry->d_fsdata; \ if (fsd->real_fops) \ r = fsd->real_fops->name(args); \ else \ r = fsd->short_fops->name(args); \ debugfs_file_put(dentry); \ return r; \} FULL_PROXY_FUNC_BOTH(llseek, loff_t, filp, PROTO(struct file *filp, loff_t offset, int whence), ARGS(filp, offset, whence)); FULL_PROXY_FUNC_BOTH(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_BOTH(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 __poll_t full_proxy_poll(struct file *filp, struct poll_table_struct *wait){ struct dentry *dentry = F_DENTRY(filp); __poll_t r = 0; const struct file_operations *real_fops; if (debugfs_file_get(dentry)) return EPOLLHUP; real_fops = debugfs_real_fops(filp); r = real_fops->poll(filp, wait); debugfs_file_put(dentry); 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 = debugfs_real_fops(filp); 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 && real_fops->release) r = real_fops->release(inode, filp); replace_fops(filp, d_inode(dentry)->i_fop); kfree(proxy_fops); fops_put(real_fops); return r;} static void __full_proxy_fops_init(struct file_operations *proxy_fops, struct debugfs_fsdata *fsd){ proxy_fops->release = full_proxy_release; if ((fsd->real_fops && fsd->real_fops->llseek) || (fsd->short_fops && fsd->short_fops->llseek)) proxy_fops->llseek = full_proxy_llseek; if ((fsd->real_fops && fsd->real_fops->read) || (fsd->short_fops && fsd->short_fops->read)) proxy_fops->read = full_proxy_read; if ((fsd->real_fops && fsd->real_fops->write) || (fsd->short_fops && fsd->short_fops->write)) proxy_fops->write = full_proxy_write; if (fsd->real_fops && fsd->real_fops->poll) proxy_fops->poll = full_proxy_poll; if (fsd->real_fops && fsd->real_fops->unlocked_ioctl) proxy_fops->unlocked_ioctl = full_proxy_unlocked_ioctl;} static int full_proxy_open(struct inode *inode, struct file *filp, enum dbgfs_get_mode mode){ struct dentry *dentry = F_DENTRY(filp); const struct file_operations *real_fops; struct file_operations *proxy_fops = NULL; struct debugfs_fsdata *fsd; int r; r = __debugfs_file_get(dentry, mode); if (r) return r == -EIO ? -ENOENT : r; fsd = dentry->d_fsdata; real_fops = fsd->real_fops; r = debugfs_locked_down(inode, filp, real_fops); if (r) goto out; if (real_fops && !fops_get(real_fops)) {#ifdef CONFIG_MODULES if (real_fops->owner && real_fops->owner->state == MODULE_STATE_GOING) { r = -ENXIO; goto out; }#endif /* 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, fsd); replace_fops(filp, proxy_fops); if (!real_fops || real_fops->open) { if (real_fops) r = real_fops->open(inode, filp); else r = simple_open(inode, filp); if (r) { replace_fops(filp, d_inode(dentry)->i_fop); goto free_proxy; } else 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:Lines 1–500 of 1444. Load more
// SPDX-License-Identifier: GPL-2.0 /* * file.c - part of debugfs, a tiny little debug file system * * Copyright (C) 2004 Greg Kroah-Hartman <greg@kroah.com> * Copyright (C) 2004 IBM Inc. * * debugfs is for people to use instead of /proc or /sys. * See Documentation/filesystems/ for more details. */ #include <linux/module.h> #include <linux/fs.h> #include <linux/seq_file.h> #include <linux/pagemap.h> #include <linux/debugfs.h> #include <linux/io.h> #include <linux/slab.h> #include <linux/atomic.h> #include <linux/device.h> #include <linux/pm_runtime.h> #include <linux/poll.h> #include <linux/security.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) { return 0; } static ssize_t default_write_file(struct file *file, const char __user *buf, size_t count, loff_t *ppos) { return count; } const struct file_operations debugfs_noop_file_operations = { .read = default_read_file, .write = default_write_file, .open = simple_open, .llseek = noop_llseek, }; #define F_DENTRY(filp) ((filp)->f_path.dentry) const struct file_operations *debugfs_real_fops(const struct file *filp) { struct debugfs_fsdata *fsd = F_DENTRY(filp)->d_fsdata; if ((unsigned long)fsd & DEBUGFS_FSDATA_IS_REAL_FOPS_BIT) { /* * Urgh, we've been called w/o a protecting * debugfs_file_get(). */ WARN_ON(1); return NULL; } return fsd->real_fops; } EXPORT_SYMBOL_GPL(debugfs_real_fops); enum dbgfs_get_mode { DBGFS_GET_ALREADY, DBGFS_GET_REGULAR, DBGFS_GET_SHORT, }; static int __debugfs_file_get(struct dentry *dentry, enum dbgfs_get_mode mode) { struct debugfs_fsdata *fsd; void *d_fsd; /* * This could only happen if some debugfs user erroneously calls * debugfs_file_get() on a dentry that isn't even a file, let * them know about it. */ if (WARN_ON(!d_is_reg(dentry))) return -EINVAL; d_fsd = READ_ONCE(dentry->d_fsdata); if (!((unsigned long)d_fsd & DEBUGFS_FSDATA_IS_REAL_FOPS_BIT)) { fsd = d_fsd; } else { if (WARN_ON(mode == DBGFS_GET_ALREADY)) return -EINVAL; fsd = kmalloc(sizeof(*fsd), GFP_KERNEL); if (!fsd) return -ENOMEM; if (mode == DBGFS_GET_SHORT) { fsd->real_fops = NULL; fsd->short_fops = (void *)((unsigned long)d_fsd & ~DEBUGFS_FSDATA_IS_REAL_FOPS_BIT); } else { fsd->real_fops = (void *)((unsigned long)d_fsd & ~DEBUGFS_FSDATA_IS_REAL_FOPS_BIT); fsd->short_fops = NULL; } refcount_set(&fsd->active_users, 1); init_completion(&fsd->active_users_drained); INIT_LIST_HEAD(&fsd->cancellations); mutex_init(&fsd->cancellations_mtx); if (cmpxchg(&dentry->d_fsdata, d_fsd, fsd) != d_fsd) { mutex_destroy(&fsd->cancellations_mtx); kfree(fsd); fsd = READ_ONCE(dentry->d_fsdata); } } /* * In case of a successful cmpxchg() above, this check is * strictly necessary and must follow it, see the comment in * __debugfs_remove_file(). * OTOH, if the cmpxchg() hasn't been executed or wasn't * successful, this serves the purpose of not starving * removers. */ if (d_unlinked(dentry)) return -EIO; if (!refcount_inc_not_zero(&fsd->active_users)) return -EIO; return 0; } /** * debugfs_file_get - mark the beginning of file data access * @dentry: the dentry object whose data is being accessed. * * Up to a matching call to debugfs_file_put(), any successive call * into the file removing functions debugfs_remove() and * debugfs_remove_recursive() will block. Since associated private * file data may only get freed after a successful return of any of * the removal functions, you may safely access it after a successful * call to debugfs_file_get() without worrying about lifetime issues. * * If -%EIO is returned, the file has already been removed and thus, * it is not safe to access any of its data. If, on the other hand, * it is allowed to access the file data, zero is returned. */ int debugfs_file_get(struct dentry *dentry) { return __debugfs_file_get(dentry, DBGFS_GET_ALREADY); } EXPORT_SYMBOL_GPL(debugfs_file_get); /** * debugfs_file_put - mark the end of file data access * @dentry: the dentry object formerly passed to * debugfs_file_get(). * * Allow any ongoing concurrent call into debugfs_remove() or * debugfs_remove_recursive() blocked by a former call to * debugfs_file_get() to proceed and return to its caller. */ void debugfs_file_put(struct dentry *dentry) { struct debugfs_fsdata *fsd = READ_ONCE(dentry->d_fsdata); if (refcount_dec_and_test(&fsd->active_users)) complete(&fsd->active_users_drained); } EXPORT_SYMBOL_GPL(debugfs_file_put); /** * debugfs_enter_cancellation - enter a debugfs cancellation * @file: the file being accessed * @cancellation: the cancellation object, the cancel callback * inside of it must be initialized * * When a debugfs file is removed it needs to wait for all active * operations to complete. However, the operation itself may need * to wait for hardware or completion of some asynchronous process * or similar. As such, it may need to be cancelled to avoid long * waits or even deadlocks. * * This function can be used inside a debugfs handler that may * need to be cancelled. As soon as this function is called, the * cancellation's 'cancel' callback may be called, at which point * the caller should proceed to call debugfs_leave_cancellation() * and leave the debugfs handler function as soon as possible. * Note that the 'cancel' callback is only ever called in the * context of some kind of debugfs_remove(). * * This function must be paired with debugfs_leave_cancellation(). */ void debugfs_enter_cancellation(struct file *file, struct debugfs_cancellation *cancellation) { struct debugfs_fsdata *fsd; struct dentry *dentry = F_DENTRY(file); INIT_LIST_HEAD(&cancellation->list); if (WARN_ON(!d_is_reg(dentry))) return; if (WARN_ON(!cancellation->cancel)) return; fsd = READ_ONCE(dentry->d_fsdata); if (WARN_ON(!fsd || ((unsigned long)fsd & DEBUGFS_FSDATA_IS_REAL_FOPS_BIT))) return; mutex_lock(&fsd->cancellations_mtx); list_add(&cancellation->list, &fsd->cancellations); mutex_unlock(&fsd->cancellations_mtx); /* if we're already removing wake it up to cancel */ if (d_unlinked(dentry)) complete(&fsd->active_users_drained); } EXPORT_SYMBOL_GPL(debugfs_enter_cancellation); /** * debugfs_leave_cancellation - leave cancellation section * @file: the file being accessed * @cancellation: the cancellation previously registered with * debugfs_enter_cancellation() * * See the documentation of debugfs_enter_cancellation(). */ void debugfs_leave_cancellation(struct file *file, struct debugfs_cancellation *cancellation) { struct debugfs_fsdata *fsd; struct dentry *dentry = F_DENTRY(file); if (WARN_ON(!d_is_reg(dentry))) return; fsd = READ_ONCE(dentry->d_fsdata); if (WARN_ON(!fsd || ((unsigned long)fsd & DEBUGFS_FSDATA_IS_REAL_FOPS_BIT))) return; mutex_lock(&fsd->cancellations_mtx); if (!list_empty(&cancellation->list)) list_del(&cancellation->list); mutex_unlock(&fsd->cancellations_mtx); } EXPORT_SYMBOL_GPL(debugfs_leave_cancellation); /* * Only permit access to world-readable files when the kernel is locked down. * We also need to exclude any file that has ways to write or alter it as root * can bypass the permissions check. */ static int debugfs_locked_down(struct inode *inode, struct file *filp, const struct file_operations *real_fops) { if ((inode->i_mode & 07777 & ~0444) == 0 && !(filp->f_mode & FMODE_WRITE) && (!real_fops || (!real_fops->unlocked_ioctl && !real_fops->compat_ioctl && !real_fops->mmap))) return 0; if (security_locked_down(LOCKDOWN_DEBUGFS)) return -EPERM; return 0; } static int open_proxy_open(struct inode *inode, struct file *filp) { struct dentry *dentry = F_DENTRY(filp); const struct file_operations *real_fops = NULL; int r; r = __debugfs_file_get(dentry, DBGFS_GET_REGULAR); if (r) return r == -EIO ? -ENOENT : r; real_fops = debugfs_real_fops(filp); r = debugfs_locked_down(inode, filp, real_fops); if (r) goto out; if (!fops_get(real_fops)) { #ifdef CONFIG_MODULES if (real_fops->owner && real_fops->owner->state == MODULE_STATE_GOING) { r = -ENXIO; goto out; } #endif /* Huh? Module did not clean up after itself at exit? */ WARN(1, "debugfs file owner did not clean up at exit: %pd", dentry); r = -ENXIO; goto out; } replace_fops(filp, real_fops); if (real_fops->open) r = real_fops->open(inode, filp); out: debugfs_file_put(dentry); return r; } 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) \ { \ struct dentry *dentry = F_DENTRY(filp); \ const struct file_operations *real_fops; \ ret_type r; \ \ r = debugfs_file_get(dentry); \ if (unlikely(r)) \ return r; \ real_fops = debugfs_real_fops(filp); \ r = real_fops->name(args); \ debugfs_file_put(dentry); \ return r; \ } #define FULL_PROXY_FUNC_BOTH(name, ret_type, filp, proto, args) \ static ret_type full_proxy_ ## name(proto) \ { \ struct dentry *dentry = F_DENTRY(filp); \ struct debugfs_fsdata *fsd; \ ret_type r; \ \ r = debugfs_file_get(dentry); \ if (unlikely(r)) \ return r; \ fsd = dentry->d_fsdata; \ if (fsd->real_fops) \ r = fsd->real_fops->name(args); \ else \ r = fsd->short_fops->name(args); \ debugfs_file_put(dentry); \ return r; \ } FULL_PROXY_FUNC_BOTH(llseek, loff_t, filp, PROTO(struct file *filp, loff_t offset, int whence), ARGS(filp, offset, whence)); FULL_PROXY_FUNC_BOTH(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_BOTH(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 __poll_t full_proxy_poll(struct file *filp, struct poll_table_struct *wait) { struct dentry *dentry = F_DENTRY(filp); __poll_t r = 0; const struct file_operations *real_fops; if (debugfs_file_get(dentry)) return EPOLLHUP; real_fops = debugfs_real_fops(filp); r = real_fops->poll(filp, wait); debugfs_file_put(dentry); 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 = debugfs_real_fops(filp); 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 && real_fops->release) r = real_fops->release(inode, filp); replace_fops(filp, d_inode(dentry)->i_fop); kfree(proxy_fops); fops_put(real_fops); return r; } static void __full_proxy_fops_init(struct file_operations *proxy_fops, struct debugfs_fsdata *fsd) { proxy_fops->release = full_proxy_release; if ((fsd->real_fops && fsd->real_fops->llseek) || (fsd->short_fops && fsd->short_fops->llseek)) proxy_fops->llseek = full_proxy_llseek; if ((fsd->real_fops && fsd->real_fops->read) || (fsd->short_fops && fsd->short_fops->read)) proxy_fops->read = full_proxy_read; if ((fsd->real_fops && fsd->real_fops->write) || (fsd->short_fops && fsd->short_fops->write)) proxy_fops->write = full_proxy_write; if (fsd->real_fops && fsd->real_fops->poll) proxy_fops->poll = full_proxy_poll; if (fsd->real_fops && fsd->real_fops->unlocked_ioctl) proxy_fops->unlocked_ioctl = full_proxy_unlocked_ioctl; } static int full_proxy_open(struct inode *inode, struct file *filp, enum dbgfs_get_mode mode) { struct dentry *dentry = F_DENTRY(filp); const struct file_operations *real_fops; struct file_operations *proxy_fops = NULL; struct debugfs_fsdata *fsd; int r; r = __debugfs_file_get(dentry, mode); if (r) return r == -EIO ? -ENOENT : r; fsd = dentry->d_fsdata; real_fops = fsd->real_fops; r = debugfs_locked_down(inode, filp, real_fops); if (r) goto out; if (real_fops && !fops_get(real_fops)) { #ifdef CONFIG_MODULES if (real_fops->owner && real_fops->owner->state == MODULE_STATE_GOING) { r = -ENXIO; goto out; } #endif /* 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, fsd); replace_fops(filp, proxy_fops); if (!real_fops || real_fops->open) { if (real_fops) r = real_fops->open(inode, filp); else r = simple_open(inode, filp); if (r) { replace_fops(filp, d_inode(dentry)->i_fop); goto free_proxy; } else 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: