diff options
Diffstat (limited to 'fs/debugfs')
| -rw-r--r-- | fs/debugfs/Makefile | 5 | ||||
| -rw-r--r-- | fs/debugfs/file.c | 1177 | ||||
| -rw-r--r-- | fs/debugfs/inode.c | 882 | ||||
| -rw-r--r-- | fs/debugfs/internal.h | 52 |
4 files changed, 2116 insertions, 0 deletions
diff --git a/fs/debugfs/Makefile b/fs/debugfs/Makefile new file mode 100644 index 000000000..9c0fe38cf --- /dev/null +++ b/fs/debugfs/Makefile @@ -0,0 +1,5 @@ +# SPDX-License-Identifier: GPL-2.0-only +debugfs-objs := inode.o file.o + +obj-$(CONFIG_DEBUG_FS) += debugfs.o + diff --git a/fs/debugfs/file.c b/fs/debugfs/file.c new file mode 100644 index 000000000..9c0aadedf --- /dev/null +++ b/fs/debugfs/file.c @@ -0,0 +1,1177 @@ +// 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); + +/** + * 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) +{ + 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 { + fsd = kmalloc(sizeof(*fsd), GFP_KERNEL); + if (!fsd) + return -ENOMEM; + + fsd->real_fops = (void *)((unsigned long)d_fsd & + ~DEBUGFS_FSDATA_IS_REAL_FOPS_BIT); + refcount_set(&fsd->active_users, 1); + init_completion(&fsd->active_users_drained); + if (cmpxchg(&dentry->d_fsdata, d_fsd, fsd) != d_fsd) { + 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; +} +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); + +/* + * 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->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); + 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; \ +} + +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 __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->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, + 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) +{ + struct dentry *dentry = F_DENTRY(filp); + const struct file_operations *real_fops = NULL; + struct file_operations *proxy_fops = NULL; + int r; + + r = debugfs_file_get(dentry); + 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 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 (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: + kfree(proxy_fops); + fops_put(real_fops); +out: + debugfs_file_put(dentry); + return r; +} + +const struct file_operations debugfs_full_proxy_file_operations = { + .open = full_proxy_open, +}; + +ssize_t debugfs_attr_read(struct file *file, char __user *buf, + size_t len, loff_t *ppos) +{ + struct dentry *dentry = F_DENTRY(file); + ssize_t ret; + + ret = debugfs_file_get(dentry); + if (unlikely(ret)) + return ret; + ret = simple_attr_read(file, buf, len, ppos); + debugfs_file_put(dentry); + return ret; +} +EXPORT_SYMBOL_GPL(debugfs_attr_read); + +static ssize_t debugfs_attr_write_xsigned(struct file *file, const char __user *buf, + size_t len, loff_t *ppos, bool is_signed) +{ + struct dentry *dentry = F_DENTRY(file); + ssize_t ret; + + ret = debugfs_file_get(dentry); + if (unlikely(ret)) + return ret; + if (is_signed) + ret = simple_attr_write_signed(file, buf, len, ppos); + else + ret = simple_attr_write(file, buf, len, ppos); + debugfs_file_put(dentry); + return ret; +} + +ssize_t debugfs_attr_write(struct file *file, const char __user *buf, + size_t len, loff_t *ppos) +{ + return debugfs_attr_write_xsigned(file, buf, len, ppos, false); +} +EXPORT_SYMBOL_GPL(debugfs_attr_write); + +ssize_t debugfs_attr_write_signed(struct file *file, const char __user *buf, + size_t len, loff_t *ppos) +{ + return debugfs_attr_write_xsigned(file, buf, len, ppos, true); +} +EXPORT_SYMBOL_GPL(debugfs_attr_write_signed); + +static struct dentry *debugfs_create_mode_unsafe(const char *name, umode_t mode, + struct dentry *parent, void *value, + const struct file_operations *fops, + const struct file_operations *fops_ro, + const struct file_operations *fops_wo) +{ + /* if there are no write bits set, make read only */ + if (!(mode & S_IWUGO)) + return debugfs_create_file_unsafe(name, mode, parent, value, + fops_ro); + /* if there are no read bits set, make write only */ + if (!(mode & S_IRUGO)) + return debugfs_create_file_unsafe(name, mode, parent, value, + fops_wo); + + return debugfs_create_file_unsafe(name, mode, parent, value, fops); +} + +static int debugfs_u8_set(void *data, u64 val) +{ + *(u8 *)data = val; + return 0; +} +static int debugfs_u8_get(void *data, u64 *val) +{ + *val = *(u8 *)data; + return 0; +} +DEFINE_DEBUGFS_ATTRIBUTE(fops_u8, debugfs_u8_get, debugfs_u8_set, "%llu\n"); +DEFINE_DEBUGFS_ATTRIBUTE(fops_u8_ro, debugfs_u8_get, NULL, "%llu\n"); +DEFINE_DEBUGFS_ATTRIBUTE(fops_u8_wo, NULL, debugfs_u8_set, "%llu\n"); + +/** + * debugfs_create_u8 - create a debugfs file that is used to read and write an unsigned 8-bit value + * @name: a pointer to a string containing the name of the file to create. + * @mode: the permission that the file should have + * @parent: a pointer to the parent dentry for this file. This should be a + * directory dentry if set. If this parameter is %NULL, then the + * file will be created in the root of the debugfs filesystem. + * @value: a pointer to the variable that the file should read to and write + * from. + * + * This function creates a file in debugfs with the given name that + * contains the value of the variable @value. If the @mode variable is so + * set, it can be read from, and written to. + */ +void debugfs_create_u8(const char *name, umode_t mode, struct dentry *parent, + u8 *value) +{ + debugfs_create_mode_unsafe(name, mode, parent, value, &fops_u8, + &fops_u8_ro, &fops_u8_wo); +} +EXPORT_SYMBOL_GPL(debugfs_create_u8); + +static int debugfs_u16_set(void *data, u64 val) +{ + *(u16 *)data = val; + return 0; +} +static int debugfs_u16_get(void *data, u64 *val) +{ + *val = *(u16 *)data; + return 0; +} +DEFINE_DEBUGFS_ATTRIBUTE(fops_u16, debugfs_u16_get, debugfs_u16_set, "%llu\n"); +DEFINE_DEBUGFS_ATTRIBUTE(fops_u16_ro, debugfs_u16_get, NULL, "%llu\n"); +DEFINE_DEBUGFS_ATTRIBUTE(fops_u16_wo, NULL, debugfs_u16_set, "%llu\n"); + +/** + * debugfs_create_u16 - create a debugfs file that is used to read and write an unsigned 16-bit value + * @name: a pointer to a string containing the name of the file to create. + * @mode: the permission that the file should have + * @parent: a pointer to the parent dentry for this file. This should be a + * directory dentry if set. If this parameter is %NULL, then the + * file will be created in the root of the debugfs filesystem. + * @value: a pointer to the variable that the file should read to and write + * from. + * + * This function creates a file in debugfs with the given name that + * contains the value of the variable @value. If the @mode variable is so + * set, it can be read from, and written to. + */ +void debugfs_create_u16(const char *name, umode_t mode, struct dentry *parent, + u16 *value) +{ + debugfs_create_mode_unsafe(name, mode, parent, value, &fops_u16, + &fops_u16_ro, &fops_u16_wo); +} +EXPORT_SYMBOL_GPL(debugfs_create_u16); + +static int debugfs_u32_set(void *data, u64 val) +{ + *(u32 *)data = val; + return 0; +} +static int debugfs_u32_get(void *data, u64 *val) +{ + *val = *(u32 *)data; + return 0; +} +DEFINE_DEBUGFS_ATTRIBUTE(fops_u32, debugfs_u32_get, debugfs_u32_set, "%llu\n"); +DEFINE_DEBUGFS_ATTRIBUTE(fops_u32_ro, debugfs_u32_get, NULL, "%llu\n"); +DEFINE_DEBUGFS_ATTRIBUTE(fops_u32_wo, NULL, debugfs_u32_set, "%llu\n"); + +/** + * debugfs_create_u32 - create a debugfs file that is used to read and write an unsigned 32-bit value + * @name: a pointer to a string containing the name of the file to create. + * @mode: the permission that the file should have + * @parent: a pointer to the parent dentry for this file. This should be a + * directory dentry if set. If this parameter is %NULL, then the + * file will be created in the root of the debugfs filesystem. + * @value: a pointer to the variable that the file should read to and write + * from. + * + * This function creates a file in debugfs with the given name that + * contains the value of the variable @value. If the @mode variable is so + * set, it can be read from, and written to. + */ +void debugfs_create_u32(const char *name, umode_t mode, struct dentry *parent, + u32 *value) +{ + debugfs_create_mode_unsafe(name, mode, parent, value, &fops_u32, + &fops_u32_ro, &fops_u32_wo); +} +EXPORT_SYMBOL_GPL(debugfs_create_u32); + +static int debugfs_u64_set(void *data, u64 val) +{ + *(u64 *)data = val; + return 0; +} + +static int debugfs_u64_get(void *data, u64 *val) +{ + *val = *(u64 *)data; + return 0; +} +DEFINE_DEBUGFS_ATTRIBUTE(fops_u64, debugfs_u64_get, debugfs_u64_set, "%llu\n"); +DEFINE_DEBUGFS_ATTRIBUTE(fops_u64_ro, debugfs_u64_get, NULL, "%llu\n"); +DEFINE_DEBUGFS_ATTRIBUTE(fops_u64_wo, NULL, debugfs_u64_set, "%llu\n"); + +/** + * debugfs_create_u64 - create a debugfs file that is used to read and write an unsigned 64-bit value + * @name: a pointer to a string containing the name of the file to create. + * @mode: the permission that the file should have + * @parent: a pointer to the parent dentry for this file. This should be a + * directory dentry if set. If this parameter is %NULL, then the + * file will be created in the root of the debugfs filesystem. + * @value: a pointer to the variable that the file should read to and write + * from. + * + * This function creates a file in debugfs with the given name that + * contains the value of the variable @value. If the @mode variable is so + * set, it can be read from, and written to. + */ +void debugfs_create_u64(const char *name, umode_t mode, struct dentry *parent, + u64 *value) +{ + debugfs_create_mode_unsafe(name, mode, parent, value, &fops_u64, + &fops_u64_ro, &fops_u64_wo); +} +EXPORT_SYMBOL_GPL(debugfs_create_u64); + +static int debugfs_ulong_set(void *data, u64 val) +{ + *(unsigned long *)data = val; + return 0; +} + +static int debugfs_ulong_get(void *data, u64 *val) +{ + *val = *(unsigned long *)data; + return 0; +} +DEFINE_DEBUGFS_ATTRIBUTE(fops_ulong, debugfs_ulong_get, debugfs_ulong_set, + "%llu\n"); +DEFINE_DEBUGFS_ATTRIBUTE(fops_ulong_ro, debugfs_ulong_get, NULL, "%llu\n"); +DEFINE_DEBUGFS_ATTRIBUTE(fops_ulong_wo, NULL, debugfs_ulong_set, "%llu\n"); + +/** + * debugfs_create_ulong - create a debugfs file that is used to read and write + * an unsigned long value. + * @name: a pointer to a string containing the name of the file to create. + * @mode: the permission that the file should have + * @parent: a pointer to the parent dentry for this file. This should be a + * directory dentry if set. If this parameter is %NULL, then the + * file will be created in the root of the debugfs filesystem. + * @value: a pointer to the variable that the file should read to and write + * from. + * + * This function creates a file in debugfs with the given name that + * contains the value of the variable @value. If the @mode variable is so + * set, it can be read from, and written to. + * + * This function will return a pointer to a dentry if it succeeds. This + * pointer must be passed to the debugfs_remove() function when the file is + * to be removed (no automatic cleanup happens if your module is unloaded, + * you are responsible here.) If an error occurs, ERR_PTR(-ERROR) will be + * returned. + * + * If debugfs is not enabled in the kernel, the value ERR_PTR(-ENODEV) will + * be returned. + */ +struct dentry *debugfs_create_ulong(const char *name, umode_t mode, + struct dentry *parent, unsigned long *value) +{ + return debugfs_create_mode_unsafe(name, mode, parent, value, + &fops_ulong, &fops_ulong_ro, + &fops_ulong_wo); +} +EXPORT_SYMBOL_GPL(debugfs_create_ulong); + +DEFINE_DEBUGFS_ATTRIBUTE(fops_x8, debugfs_u8_get, debugfs_u8_set, "0x%02llx\n"); +DEFINE_DEBUGFS_ATTRIBUTE(fops_x8_ro, debugfs_u8_get, NULL, "0x%02llx\n"); +DEFINE_DEBUGFS_ATTRIBUTE(fops_x8_wo, NULL, debugfs_u8_set, "0x%02llx\n"); + +DEFINE_DEBUGFS_ATTRIBUTE(fops_x16, debugfs_u16_get, debugfs_u16_set, + "0x%04llx\n"); +DEFINE_DEBUGFS_ATTRIBUTE(fops_x16_ro, debugfs_u16_get, NULL, "0x%04llx\n"); +DEFINE_DEBUGFS_ATTRIBUTE(fops_x16_wo, NULL, debugfs_u16_set, "0x%04llx\n"); + +DEFINE_DEBUGFS_ATTRIBUTE(fops_x32, debugfs_u32_get, debugfs_u32_set, + "0x%08llx\n"); +DEFINE_DEBUGFS_ATTRIBUTE(fops_x32_ro, debugfs_u32_get, NULL, "0x%08llx\n"); +DEFINE_DEBUGFS_ATTRIBUTE(fops_x32_wo, NULL, debugfs_u32_set, "0x%08llx\n"); + +DEFINE_DEBUGFS_ATTRIBUTE(fops_x64, debugfs_u64_get, debugfs_u64_set, + "0x%016llx\n"); +DEFINE_DEBUGFS_ATTRIBUTE(fops_x64_ro, debugfs_u64_get, NULL, "0x%016llx\n"); +DEFINE_DEBUGFS_ATTRIBUTE(fops_x64_wo, NULL, debugfs_u64_set, "0x%016llx\n"); + +/* + * debugfs_create_x{8,16,32,64} - create a debugfs file that is used to read and write an unsigned {8,16,32,64}-bit value + * + * These functions are exactly the same as the above functions (but use a hex + * output for the decimal challenged). For details look at the above unsigned + * decimal functions. + */ + +/** + * debugfs_create_x8 - create a debugfs file that is used to read and write an unsigned 8-bit value + * @name: a pointer to a string containing the name of the file to create. + * @mode: the permission that the file should have + * @parent: a pointer to the parent dentry for this file. This should be a + * directory dentry if set. If this parameter is %NULL, then the + * file will be created in the root of the debugfs filesystem. + * @value: a pointer to the variable that the file should read to and write + * from. + */ +void debugfs_create_x8(const char *name, umode_t mode, struct dentry *parent, + u8 *value) +{ + debugfs_create_mode_unsafe(name, mode, parent, value, &fops_x8, + &fops_x8_ro, &fops_x8_wo); +} +EXPORT_SYMBOL_GPL(debugfs_create_x8); + +/** + * debugfs_create_x16 - create a debugfs file that is used to read and write an unsigned 16-bit value + * @name: a pointer to a string containing the name of the file to create. + * @mode: the permission that the file should have + * @parent: a pointer to the parent dentry for this file. This should be a + * directory dentry if set. If this parameter is %NULL, then the + * file will be created in the root of the debugfs filesystem. + * @value: a pointer to the variable that the file should read to and write + * from. + */ +void debugfs_create_x16(const char *name, umode_t mode, struct dentry *parent, + u16 *value) +{ + debugfs_create_mode_unsafe(name, mode, parent, value, &fops_x16, + &fops_x16_ro, &fops_x16_wo); +} +EXPORT_SYMBOL_GPL(debugfs_create_x16); + +/** + * debugfs_create_x32 - create a debugfs file that is used to read and write an unsigned 32-bit value + * @name: a pointer to a string containing the name of the file to create. + * @mode: the permission that the file should have + * @parent: a pointer to the parent dentry for this file. This should be a + * directory dentry if set. If this parameter is %NULL, then the + * file will be created in the root of the debugfs filesystem. + * @value: a pointer to the variable that the file should read to and write + * from. + */ +void debugfs_create_x32(const char *name, umode_t mode, struct dentry *parent, + u32 *value) +{ + debugfs_create_mode_unsafe(name, mode, parent, value, &fops_x32, + &fops_x32_ro, &fops_x32_wo); +} +EXPORT_SYMBOL_GPL(debugfs_create_x32); + +/** + * debugfs_create_x64 - create a debugfs file that is used to read and write an unsigned 64-bit value + * @name: a pointer to a string containing the name of the file to create. + * @mode: the permission that the file should have + * @parent: a pointer to the parent dentry for this file. This should be a + * directory dentry if set. If this parameter is %NULL, then the + * file will be created in the root of the debugfs filesystem. + * @value: a pointer to the variable that the file should read to and write + * from. + */ +void debugfs_create_x64(const char *name, umode_t mode, struct dentry *parent, + u64 *value) +{ + debugfs_create_mode_unsafe(name, mode, parent, value, &fops_x64, + &fops_x64_ro, &fops_x64_wo); +} +EXPORT_SYMBOL_GPL(debugfs_create_x64); + + +static int debugfs_size_t_set(void *data, u64 val) +{ + *(size_t *)data = val; + return 0; +} +static int debugfs_size_t_get(void *data, u64 *val) +{ + *val = *(size_t *)data; + return 0; +} +DEFINE_DEBUGFS_ATTRIBUTE(fops_size_t, debugfs_size_t_get, debugfs_size_t_set, + "%llu\n"); /* %llu and %zu are more or less the same */ +DEFINE_DEBUGFS_ATTRIBUTE(fops_size_t_ro, debugfs_size_t_get, NULL, "%llu\n"); +DEFINE_DEBUGFS_ATTRIBUTE(fops_size_t_wo, NULL, debugfs_size_t_set, "%llu\n"); + +/** + * debugfs_create_size_t - create a debugfs file that is used to read and write an size_t value + * @name: a pointer to a string containing the name of the file to create. + * @mode: the permission that the file should have + * @parent: a pointer to the parent dentry for this file. This should be a + * directory dentry if set. If this parameter is %NULL, then the + * file will be created in the root of the debugfs filesystem. + * @value: a pointer to the variable that the file should read to and write + * from. + */ +void debugfs_create_size_t(const char *name, umode_t mode, + struct dentry *parent, size_t *value) +{ + debugfs_create_mode_unsafe(name, mode, parent, value, &fops_size_t, + &fops_size_t_ro, &fops_size_t_wo); +} +EXPORT_SYMBOL_GPL(debugfs_create_size_t); + +static int debugfs_atomic_t_set(void *data, u64 val) +{ + atomic_set((atomic_t *)data, val); + return 0; +} +static int debugfs_atomic_t_get(void *data, u64 *val) +{ + *val = atomic_read((atomic_t *)data); + return 0; +} +DEFINE_DEBUGFS_ATTRIBUTE_SIGNED(fops_atomic_t, debugfs_atomic_t_get, + debugfs_atomic_t_set, "%lld\n"); +DEFINE_DEBUGFS_ATTRIBUTE_SIGNED(fops_atomic_t_ro, debugfs_atomic_t_get, NULL, + "%lld\n"); +DEFINE_DEBUGFS_ATTRIBUTE_SIGNED(fops_atomic_t_wo, NULL, debugfs_atomic_t_set, + "%lld\n"); + +/** + * debugfs_create_atomic_t - create a debugfs file that is used to read and + * write an atomic_t value + * @name: a pointer to a string containing the name of the file to create. + * @mode: the permission that the file should have + * @parent: a pointer to the parent dentry for this file. This should be a + * directory dentry if set. If this parameter is %NULL, then the + * file will be created in the root of the debugfs filesystem. + * @value: a pointer to the variable that the file should read to and write + * from. + */ +void debugfs_create_atomic_t(const char *name, umode_t mode, + struct dentry *parent, atomic_t *value) +{ + debugfs_create_mode_unsafe(name, mode, parent, value, &fops_atomic_t, + &fops_atomic_t_ro, &fops_atomic_t_wo); +} +EXPORT_SYMBOL_GPL(debugfs_create_atomic_t); + +ssize_t debugfs_read_file_bool(struct file *file, char __user *user_buf, + size_t count, loff_t *ppos) +{ + char buf[3]; + bool val; + int r; + struct dentry *dentry = F_DENTRY(file); + + r = debugfs_file_get(dentry); + if (unlikely(r)) + return r; + val = *(bool *)file->private_data; + debugfs_file_put(dentry); + + if (val) + buf[0] = 'Y'; + else + buf[0] = 'N'; + buf[1] = '\n'; + buf[2] = 0x00; + return simple_read_from_buffer(user_buf, count, ppos, buf, 2); +} +EXPORT_SYMBOL_GPL(debugfs_read_file_bool); + +ssize_t debugfs_write_file_bool(struct file *file, const char __user *user_buf, + size_t count, loff_t *ppos) +{ + bool bv; + int r; + bool *val = file->private_data; + struct dentry *dentry = F_DENTRY(file); + + r = kstrtobool_from_user(user_buf, count, &bv); + if (!r) { + r = debugfs_file_get(dentry); + if (unlikely(r)) + return r; + *val = bv; + debugfs_file_put(dentry); + } + + return count; +} +EXPORT_SYMBOL_GPL(debugfs_write_file_bool); + +static const struct file_operations fops_bool = { + .read = debugfs_read_file_bool, + .write = debugfs_write_file_bool, + .open = simple_open, + .llseek = default_llseek, +}; + +static const struct file_operations fops_bool_ro = { + .read = debugfs_read_file_bool, + .open = simple_open, + .llseek = default_llseek, +}; + +static const struct file_operations fops_bool_wo = { + .write = debugfs_write_file_bool, + .open = simple_open, + .llseek = default_llseek, +}; + +/** + * debugfs_create_bool - create a debugfs file that is used to read and write a boolean value + * @name: a pointer to a string containing the name of the file to create. + * @mode: the permission that the file should have + * @parent: a pointer to the parent dentry for this file. This should be a + * directory dentry if set. If this parameter is %NULL, then the + * file will be created in the root of the debugfs filesystem. + * @value: a pointer to the variable that the file should read to and write + * from. + * + * This function creates a file in debugfs with the given name that + * contains the value of the variable @value. If the @mode variable is so + * set, it can be read from, and written to. + * + * This function will return a pointer to a dentry if it succeeds. This + * pointer must be passed to the debugfs_remove() function when the file is + * to be removed (no automatic cleanup happens if your module is unloaded, + * you are responsible here.) If an error occurs, ERR_PTR(-ERROR) will be + * returned. + * + * If debugfs is not enabled in the kernel, the value ERR_PTR(-ENODEV) will + * be returned. + */ +struct dentry *debugfs_create_bool(const char *name, umode_t mode, + struct dentry *parent, bool *value) +{ + return debugfs_create_mode_unsafe(name, mode, parent, value, &fops_bool, + &fops_bool_ro, &fops_bool_wo); +} +EXPORT_SYMBOL_GPL(debugfs_create_bool); + +static ssize_t read_file_blob(struct file *file, char __user *user_buf, + size_t count, loff_t *ppos) +{ + struct debugfs_blob_wrapper *blob = file->private_data; + struct dentry *dentry = F_DENTRY(file); + ssize_t r; + + r = debugfs_file_get(dentry); + if (unlikely(r)) + return r; + r = simple_read_from_buffer(user_buf, count, ppos, blob->data, + blob->size); + debugfs_file_put(dentry); + return r; +} + +static const struct file_operations fops_blob = { + .read = read_file_blob, + .open = simple_open, + .llseek = default_llseek, +}; + +/** + * debugfs_create_blob - create a debugfs file that is used to read a binary blob + * @name: a pointer to a string containing the name of the file to create. + * @mode: the permission that the file should have + * @parent: a pointer to the parent dentry for this file. This should be a + * directory dentry if set. If this parameter is %NULL, then the + * file will be created in the root of the debugfs filesystem. + * @blob: a pointer to a struct debugfs_blob_wrapper which contains a pointer + * to the blob data and the size of the data. + * + * This function creates a file in debugfs with the given name that exports + * @blob->data as a binary blob. If the @mode variable is so set it can be + * read from. Writing is not supported. + * + * This function will return a pointer to a dentry if it succeeds. This + * pointer must be passed to the debugfs_remove() function when the file is + * to be removed (no automatic cleanup happens if your module is unloaded, + * you are responsible here.) If an error occurs, ERR_PTR(-ERROR) will be + * returned. + * + * If debugfs is not enabled in the kernel, the value ERR_PTR(-ENODEV) will + * be returned. + */ +struct dentry *debugfs_create_blob(const char *name, umode_t mode, + struct dentry *parent, + struct debugfs_blob_wrapper *blob) +{ + return debugfs_create_file_unsafe(name, mode, parent, blob, &fops_blob); +} +EXPORT_SYMBOL_GPL(debugfs_create_blob); + +static size_t u32_format_array(char *buf, size_t bufsize, + u32 *array, int array_size) +{ + size_t ret = 0; + + while (--array_size >= 0) { + size_t len; + char term = array_size ? ' ' : '\n'; + + len = snprintf(buf, bufsize, "%u%c", *array++, term); + ret += len; + + buf += len; + bufsize -= len; + } + return ret; +} + +static int u32_array_open(struct inode *inode, struct file *file) +{ + struct debugfs_u32_array *data = inode->i_private; + int size, elements = data->n_elements; + char *buf; + + /* + * Max size: + * - 10 digits + ' '/'\n' = 11 bytes per number + * - terminating NUL character + */ + size = elements*11; + buf = kmalloc(size+1, GFP_KERNEL); + if (!buf) + return -ENOMEM; + buf[size] = 0; + + file->private_data = buf; + u32_format_array(buf, size, data->array, data->n_elements); + + return nonseekable_open(inode, file); +} + +static ssize_t u32_array_read(struct file *file, char __user *buf, size_t len, + loff_t *ppos) +{ + size_t size = strlen(file->private_data); + + return simple_read_from_buffer(buf, len, ppos, + file->private_data, size); +} + +static int u32_array_release(struct inode *inode, struct file *file) +{ + kfree(file->private_data); + + return 0; +} + +static const struct file_operations u32_array_fops = { + .owner = THIS_MODULE, + .open = u32_array_open, + .release = u32_array_release, + .read = u32_array_read, + .llseek = no_llseek, +}; + +/** + * debugfs_create_u32_array - create a debugfs file that is used to read u32 + * array. + * @name: a pointer to a string containing the name of the file to create. + * @mode: the permission that the file should have. + * @parent: a pointer to the parent dentry for this file. This should be a + * directory dentry if set. If this parameter is %NULL, then the + * file will be created in the root of the debugfs filesystem. + * @array: wrapper struct containing data pointer and size of the array. + * + * This function creates a file in debugfs with the given name that exports + * @array as data. If the @mode variable is so set it can be read from. + * Writing is not supported. Seek within the file is also not supported. + * Once array is created its size can not be changed. + */ +void debugfs_create_u32_array(const char *name, umode_t mode, + struct dentry *parent, + struct debugfs_u32_array *array) +{ + debugfs_create_file_unsafe(name, mode, parent, array, &u32_array_fops); +} +EXPORT_SYMBOL_GPL(debugfs_create_u32_array); + +#ifdef CONFIG_HAS_IOMEM + +/* + * The regset32 stuff is used to print 32-bit registers using the + * seq_file utilities. We offer printing a register set in an already-opened + * sequential file or create a debugfs file that only prints a regset32. + */ + +/** + * debugfs_print_regs32 - use seq_print to describe a set of registers + * @s: the seq_file structure being used to generate output + * @regs: an array if struct debugfs_reg32 structures + * @nregs: the length of the above array + * @base: the base address to be used in reading the registers + * @prefix: a string to be prefixed to every output line + * + * This function outputs a text block describing the current values of + * some 32-bit hardware registers. It is meant to be used within debugfs + * files based on seq_file that need to show registers, intermixed with other + * information. The prefix argument may be used to specify a leading string, + * because some peripherals have several blocks of identical registers, + * for example configuration of dma channels + */ +void debugfs_print_regs32(struct seq_file *s, const struct debugfs_reg32 *regs, + int nregs, void __iomem *base, char *prefix) +{ + int i; + + for (i = 0; i < nregs; i++, regs++) { + if (prefix) + seq_printf(s, "%s", prefix); + seq_printf(s, "%s = 0x%08x\n", regs->name, + readl(base + regs->offset)); + if (seq_has_overflowed(s)) + break; + } +} +EXPORT_SYMBOL_GPL(debugfs_print_regs32); + +static int debugfs_show_regset32(struct seq_file *s, void *data) +{ + struct debugfs_regset32 *regset = s->private; + + if (regset->dev) + pm_runtime_get_sync(regset->dev); + + debugfs_print_regs32(s, regset->regs, regset->nregs, regset->base, ""); + + if (regset->dev) + pm_runtime_put(regset->dev); + + return 0; +} + +static int debugfs_open_regset32(struct inode *inode, struct file *file) +{ + return single_open(file, debugfs_show_regset32, inode->i_private); +} + +static const struct file_operations fops_regset32 = { + .open = debugfs_open_regset32, + .read = seq_read, + .llseek = seq_lseek, + .release = single_release, +}; + +/** + * debugfs_create_regset32 - create a debugfs file that returns register values + * @name: a pointer to a string containing the name of the file to create. + * @mode: the permission that the file should have + * @parent: a pointer to the parent dentry for this file. This should be a + * directory dentry if set. If this parameter is %NULL, then the + * file will be created in the root of the debugfs filesystem. + * @regset: a pointer to a struct debugfs_regset32, which contains a pointer + * to an array of register definitions, the array size and the base + * address where the register bank is to be found. + * + * This function creates a file in debugfs with the given name that reports + * the names and values of a set of 32-bit registers. If the @mode variable + * is so set it can be read from. Writing is not supported. + */ +void debugfs_create_regset32(const char *name, umode_t mode, + struct dentry *parent, + struct debugfs_regset32 *regset) +{ + debugfs_create_file(name, mode, parent, regset, &fops_regset32); +} +EXPORT_SYMBOL_GPL(debugfs_create_regset32); + +#endif /* CONFIG_HAS_IOMEM */ + +struct debugfs_devm_entry { + int (*read)(struct seq_file *seq, void *data); + struct device *dev; +}; + +static int debugfs_devm_entry_open(struct inode *inode, struct file *f) +{ + struct debugfs_devm_entry *entry = inode->i_private; + + return single_open(f, entry->read, entry->dev); +} + +static const struct file_operations debugfs_devm_entry_ops = { + .owner = THIS_MODULE, + .open = debugfs_devm_entry_open, + .release = single_release, + .read = seq_read, + .llseek = seq_lseek +}; + +/** + * debugfs_create_devm_seqfile - create a debugfs file that is bound to device. + * + * @dev: device related to this debugfs file. + * @name: name of the debugfs file. + * @parent: a pointer to the parent dentry for this file. This should be a + * directory dentry if set. If this parameter is %NULL, then the + * file will be created in the root of the debugfs filesystem. + * @read_fn: function pointer called to print the seq_file content. + */ +void debugfs_create_devm_seqfile(struct device *dev, const char *name, + struct dentry *parent, + int (*read_fn)(struct seq_file *s, void *data)) +{ + struct debugfs_devm_entry *entry; + + if (IS_ERR(parent)) + return; + + entry = devm_kzalloc(dev, sizeof(*entry), GFP_KERNEL); + if (!entry) + return; + + entry->read = read_fn; + entry->dev = dev; + + debugfs_create_file(name, S_IRUGO, parent, entry, + &debugfs_devm_entry_ops); +} +EXPORT_SYMBOL_GPL(debugfs_create_devm_seqfile); diff --git a/fs/debugfs/inode.c b/fs/debugfs/inode.c new file mode 100644 index 000000000..d04930c19 --- /dev/null +++ b/fs/debugfs/inode.c @@ -0,0 +1,882 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * inode.c - part of debugfs, a tiny little debug file system + * + * Copyright (C) 2004,2019 Greg Kroah-Hartman <greg@kroah.com> + * Copyright (C) 2004 IBM Inc. + * Copyright (C) 2019 Linux Foundation <gregkh@linuxfoundation.org> + * + * debugfs is for people to use instead of /proc or /sys. + * See ./Documentation/core-api/kernel-api.rst for more details. + */ + +#define pr_fmt(fmt) "debugfs: " fmt + +#include <linux/module.h> +#include <linux/fs.h> +#include <linux/mount.h> +#include <linux/pagemap.h> +#include <linux/init.h> +#include <linux/kobject.h> +#include <linux/namei.h> +#include <linux/debugfs.h> +#include <linux/fsnotify.h> +#include <linux/string.h> +#include <linux/seq_file.h> +#include <linux/parser.h> +#include <linux/magic.h> +#include <linux/slab.h> +#include <linux/security.h> + +#include "internal.h" + +#define DEBUGFS_DEFAULT_MODE 0700 + +static struct vfsmount *debugfs_mount; +static int debugfs_mount_count; +static bool debugfs_registered; +static unsigned int debugfs_allow __ro_after_init = DEFAULT_DEBUGFS_ALLOW_BITS; + +/* + * Don't allow access attributes to be changed whilst the kernel is locked down + * so that we can use the file mode as part of a heuristic to determine whether + * to lock down individual files. + */ +static int debugfs_setattr(struct dentry *dentry, struct iattr *ia) +{ + int ret = security_locked_down(LOCKDOWN_DEBUGFS); + + if (ret && (ia->ia_valid & (ATTR_MODE | ATTR_UID | ATTR_GID))) + return ret; + return simple_setattr(dentry, ia); +} + +static const struct inode_operations debugfs_file_inode_operations = { + .setattr = debugfs_setattr, +}; +static const struct inode_operations debugfs_dir_inode_operations = { + .lookup = simple_lookup, + .setattr = debugfs_setattr, +}; +static const struct inode_operations debugfs_symlink_inode_operations = { + .get_link = simple_get_link, + .setattr = debugfs_setattr, +}; + +static struct inode *debugfs_get_inode(struct super_block *sb) +{ + struct inode *inode = new_inode(sb); + if (inode) { + inode->i_ino = get_next_ino(); + inode->i_atime = inode->i_mtime = + inode->i_ctime = current_time(inode); + } + return inode; +} + +struct debugfs_mount_opts { + kuid_t uid; + kgid_t gid; + umode_t mode; +}; + +enum { + Opt_uid, + Opt_gid, + Opt_mode, + Opt_err +}; + +static const match_table_t tokens = { + {Opt_uid, "uid=%u"}, + {Opt_gid, "gid=%u"}, + {Opt_mode, "mode=%o"}, + {Opt_err, NULL} +}; + +struct debugfs_fs_info { + struct debugfs_mount_opts mount_opts; +}; + +static int debugfs_parse_options(char *data, struct debugfs_mount_opts *opts) +{ + substring_t args[MAX_OPT_ARGS]; + int option; + int token; + kuid_t uid; + kgid_t gid; + char *p; + + opts->mode = DEBUGFS_DEFAULT_MODE; + + while ((p = strsep(&data, ",")) != NULL) { + if (!*p) + continue; + + token = match_token(p, tokens, args); + switch (token) { + case Opt_uid: + if (match_int(&args[0], &option)) + return -EINVAL; + uid = make_kuid(current_user_ns(), option); + if (!uid_valid(uid)) + return -EINVAL; + opts->uid = uid; + break; + case Opt_gid: + if (match_int(&args[0], &option)) + return -EINVAL; + gid = make_kgid(current_user_ns(), option); + if (!gid_valid(gid)) + return -EINVAL; + opts->gid = gid; + break; + case Opt_mode: + if (match_octal(&args[0], &option)) + return -EINVAL; + opts->mode = option & S_IALLUGO; + break; + /* + * We might like to report bad mount options here; + * but traditionally debugfs has ignored all mount options + */ + } + } + + return 0; +} + +static int debugfs_apply_options(struct super_block *sb) +{ + struct debugfs_fs_info *fsi = sb->s_fs_info; + struct inode *inode = d_inode(sb->s_root); + struct debugfs_mount_opts *opts = &fsi->mount_opts; + + inode->i_mode &= ~S_IALLUGO; + inode->i_mode |= opts->mode; + + inode->i_uid = opts->uid; + inode->i_gid = opts->gid; + + return 0; +} + +static int debugfs_remount(struct super_block *sb, int *flags, char *data) +{ + int err; + struct debugfs_fs_info *fsi = sb->s_fs_info; + + sync_filesystem(sb); + err = debugfs_parse_options(data, &fsi->mount_opts); + if (err) + goto fail; + + debugfs_apply_options(sb); + +fail: + return err; +} + +static int debugfs_show_options(struct seq_file *m, struct dentry *root) +{ + struct debugfs_fs_info *fsi = root->d_sb->s_fs_info; + struct debugfs_mount_opts *opts = &fsi->mount_opts; + + if (!uid_eq(opts->uid, GLOBAL_ROOT_UID)) + seq_printf(m, ",uid=%u", + from_kuid_munged(&init_user_ns, opts->uid)); + if (!gid_eq(opts->gid, GLOBAL_ROOT_GID)) + seq_printf(m, ",gid=%u", + from_kgid_munged(&init_user_ns, opts->gid)); + if (opts->mode != DEBUGFS_DEFAULT_MODE) + seq_printf(m, ",mode=%o", opts->mode); + + return 0; +} + +static void debugfs_free_inode(struct inode *inode) +{ + if (S_ISLNK(inode->i_mode)) + kfree(inode->i_link); + free_inode_nonrcu(inode); +} + +static const struct super_operations debugfs_super_operations = { + .statfs = simple_statfs, + .remount_fs = debugfs_remount, + .show_options = debugfs_show_options, + .free_inode = debugfs_free_inode, +}; + +static void debugfs_release_dentry(struct dentry *dentry) +{ + struct debugfs_fsdata *fsd = dentry->d_fsdata; + + if ((unsigned long)fsd & DEBUGFS_FSDATA_IS_REAL_FOPS_BIT) + return; + + kfree(fsd); +} + +static struct vfsmount *debugfs_automount(struct path *path) +{ + struct debugfs_fsdata *fsd = path->dentry->d_fsdata; + + return fsd->automount(path->dentry, d_inode(path->dentry)->i_private); +} + +static const struct dentry_operations debugfs_dops = { + .d_delete = always_delete_dentry, + .d_release = debugfs_release_dentry, + .d_automount = debugfs_automount, +}; + +static int debug_fill_super(struct super_block *sb, void *data, int silent) +{ + static const struct tree_descr debug_files[] = {{""}}; + struct debugfs_fs_info *fsi; + int err; + + fsi = kzalloc(sizeof(struct debugfs_fs_info), GFP_KERNEL); + sb->s_fs_info = fsi; + if (!fsi) { + err = -ENOMEM; + goto fail; + } + + err = debugfs_parse_options(data, &fsi->mount_opts); + if (err) + goto fail; + + err = simple_fill_super(sb, DEBUGFS_MAGIC, debug_files); + if (err) + goto fail; + + sb->s_op = &debugfs_super_operations; + sb->s_d_op = &debugfs_dops; + + debugfs_apply_options(sb); + + return 0; + +fail: + kfree(fsi); + sb->s_fs_info = NULL; + return err; +} + +static struct dentry *debug_mount(struct file_system_type *fs_type, + int flags, const char *dev_name, + void *data) +{ + if (!(debugfs_allow & DEBUGFS_ALLOW_API)) + return ERR_PTR(-EPERM); + + return mount_single(fs_type, flags, data, debug_fill_super); +} + +static struct file_system_type debug_fs_type = { + .owner = THIS_MODULE, + .name = "debugfs", + .mount = debug_mount, + .kill_sb = kill_litter_super, +}; +MODULE_ALIAS_FS("debugfs"); + +/** + * debugfs_lookup() - look up an existing debugfs file + * @name: a pointer to a string containing the name of the file to look up. + * @parent: a pointer to the parent dentry of the file. + * + * This function will return a pointer to a dentry if it succeeds. If the file + * doesn't exist or an error occurs, %NULL will be returned. The returned + * dentry must be passed to dput() when it is no longer needed. + * + * If debugfs is not enabled in the kernel, the value -%ENODEV will be + * returned. + */ +struct dentry *debugfs_lookup(const char *name, struct dentry *parent) +{ + struct dentry *dentry; + + if (!debugfs_initialized() || IS_ERR_OR_NULL(name) || IS_ERR(parent)) + return NULL; + + if (!parent) + parent = debugfs_mount->mnt_root; + + dentry = lookup_positive_unlocked(name, parent, strlen(name)); + if (IS_ERR(dentry)) + return NULL; + return dentry; +} +EXPORT_SYMBOL_GPL(debugfs_lookup); + +static struct dentry *start_creating(const char *name, struct dentry *parent) +{ + struct dentry *dentry; + int error; + + if (!(debugfs_allow & DEBUGFS_ALLOW_API)) + return ERR_PTR(-EPERM); + + if (!debugfs_initialized()) + return ERR_PTR(-ENOENT); + + pr_debug("creating file '%s'\n", name); + + if (IS_ERR(parent)) + return parent; + + error = simple_pin_fs(&debug_fs_type, &debugfs_mount, + &debugfs_mount_count); + if (error) { + pr_err("Unable to pin filesystem for file '%s'\n", name); + return ERR_PTR(error); + } + + /* If the parent is not specified, we create it in the root. + * We need the root dentry to do this, which is in the super + * block. A pointer to that is in the struct vfsmount that we + * have around. + */ + if (!parent) + parent = debugfs_mount->mnt_root; + + inode_lock(d_inode(parent)); + if (unlikely(IS_DEADDIR(d_inode(parent)))) + dentry = ERR_PTR(-ENOENT); + else + dentry = lookup_one_len(name, parent, strlen(name)); + if (!IS_ERR(dentry) && d_really_is_positive(dentry)) { + if (d_is_dir(dentry)) + pr_err("Directory '%s' with parent '%s' already present!\n", + name, parent->d_name.name); + else + pr_err("File '%s' in directory '%s' already present!\n", + name, parent->d_name.name); + dput(dentry); + dentry = ERR_PTR(-EEXIST); + } + + if (IS_ERR(dentry)) { + inode_unlock(d_inode(parent)); + simple_release_fs(&debugfs_mount, &debugfs_mount_count); + } + + return dentry; +} + +static struct dentry *failed_creating(struct dentry *dentry) +{ + inode_unlock(d_inode(dentry->d_parent)); + dput(dentry); + simple_release_fs(&debugfs_mount, &debugfs_mount_count); + return ERR_PTR(-ENOMEM); +} + +static struct dentry *end_creating(struct dentry *dentry) +{ + inode_unlock(d_inode(dentry->d_parent)); + 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 dentry; + + if (!(debugfs_allow & DEBUGFS_ALLOW_API)) { + failed_creating(dentry); + return ERR_PTR(-EPERM); + } + + inode = debugfs_get_inode(dentry->d_sb); + if (unlikely(!inode)) { + pr_err("out of free dentries, can not create file '%s'\n", + name); + return failed_creating(dentry); + } + + inode->i_mode = mode; + inode->i_private = data; + + inode->i_op = &debugfs_file_inode_operations; + inode->i_fop = proxy_fops; + dentry->d_fsdata = (void *)((unsigned long)real_fops | + DEBUGFS_FSDATA_IS_REAL_FOPS_BIT); + + 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. + * @mode: the permission that the file should have. + * @parent: a pointer to the parent dentry for this file. This should be a + * directory dentry if set. If this parameter is NULL, then the + * file will be created in the root of the debugfs filesystem. + * @data: a pointer to something that the caller will want to get to later + * on. The inode.i_private pointer will point to this value on + * the open() call. + * @fops: a pointer to a struct file_operations that should be used for + * this file. + * + * This is the basic "create a file" function for debugfs. It allows for a + * wide range of flexibility in creating a file, or a directory (if you want + * to create a directory, the debugfs_create_dir() function is + * recommended to be used instead.) + * + * This function will return a pointer to a dentry if it succeeds. This + * pointer must be passed to the debugfs_remove() function when the file is + * to be removed (no automatic cleanup happens if your module is unloaded, + * you are responsible here.) If an error occurs, ERR_PTR(-ERROR) will be + * returned. + * + * If debugfs is not enabled in the kernel, the value -%ENODEV will be + * returned. + */ +struct dentry *debugfs_create_file(const char *name, umode_t mode, + struct dentry *parent, void *data, + const struct file_operations *fops) +{ + + 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); + +/** + * debugfs_create_file_unsafe - create a file in the debugfs filesystem + * @name: a pointer to a string containing the name of the file to create. + * @mode: the permission that the file should have. + * @parent: a pointer to the parent dentry for this file. This should be a + * directory dentry if set. If this parameter is NULL, then the + * file will be created in the root of the debugfs filesystem. + * @data: a pointer to something that the caller will want to get to later + * on. The inode.i_private pointer will point to this value on + * the open() call. + * @fops: a pointer to a struct file_operations that should be used for + * this file. + * + * debugfs_create_file_unsafe() is completely analogous to + * debugfs_create_file(), the only difference being that the fops + * handed it will not get protected against file removals by the + * debugfs core. + * + * It is your responsibility to protect your struct file_operation + * methods against file removals by means of debugfs_file_get() + * and debugfs_file_put(). ->open() is still protected by + * debugfs though. + * + * Any struct file_operations defined by means of + * DEFINE_DEBUGFS_ATTRIBUTE() is protected against file removals and + * thus, may be used here. + */ +struct dentry *debugfs_create_file_unsafe(const char *name, umode_t mode, + struct dentry *parent, void *data, + const struct file_operations *fops) +{ + + 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_unsafe); + +/** + * debugfs_create_file_size - create a file in the debugfs filesystem + * @name: a pointer to a string containing the name of the file to create. + * @mode: the permission that the file should have. + * @parent: a pointer to the parent dentry for this file. This should be a + * directory dentry if set. If this parameter is NULL, then the + * file will be created in the root of the debugfs filesystem. + * @data: a pointer to something that the caller will want to get to later + * on. The inode.i_private pointer will point to this value on + * the open() call. + * @fops: a pointer to a struct file_operations that should be used for + * this file. + * @file_size: initial file size + * + * This is the basic "create a file" function for debugfs. It allows for a + * wide range of flexibility in creating a file, or a directory (if you want + * to create a directory, the debugfs_create_dir() function is + * recommended to be used instead.) + */ +void debugfs_create_file_size(const char *name, umode_t mode, + struct dentry *parent, void *data, + const struct file_operations *fops, + loff_t file_size) +{ + struct dentry *de = debugfs_create_file(name, mode, parent, data, fops); + + if (!IS_ERR(de)) + d_inode(de)->i_size = file_size; +} +EXPORT_SYMBOL_GPL(debugfs_create_file_size); + +/** + * debugfs_create_dir - create a directory in the debugfs filesystem + * @name: a pointer to a string containing the name of the directory to + * create. + * @parent: a pointer to the parent dentry for this file. This should be a + * directory dentry if set. If this parameter is NULL, then the + * directory will be created in the root of the debugfs filesystem. + * + * This function creates a directory in debugfs with the given name. + * + * This function will return a pointer to a dentry if it succeeds. This + * pointer must be passed to the debugfs_remove() function when the file is + * to be removed (no automatic cleanup happens if your module is unloaded, + * you are responsible here.) If an error occurs, ERR_PTR(-ERROR) will be + * returned. + * + * If debugfs is not enabled in the kernel, the value -%ENODEV will be + * returned. + */ +struct dentry *debugfs_create_dir(const char *name, struct dentry *parent) +{ + struct dentry *dentry = start_creating(name, parent); + struct inode *inode; + + if (IS_ERR(dentry)) + return dentry; + + if (!(debugfs_allow & DEBUGFS_ALLOW_API)) { + failed_creating(dentry); + return ERR_PTR(-EPERM); + } + + inode = debugfs_get_inode(dentry->d_sb); + if (unlikely(!inode)) { + pr_err("out of free dentries, can not create directory '%s'\n", + name); + return failed_creating(dentry); + } + + inode->i_mode = S_IFDIR | S_IRWXU | S_IRUGO | S_IXUGO; + inode->i_op = &debugfs_dir_inode_operations; + inode->i_fop = &simple_dir_operations; + + /* directory inodes start off with i_nlink == 2 (for "." entry) */ + inc_nlink(inode); + d_instantiate(dentry, inode); + inc_nlink(d_inode(dentry->d_parent)); + fsnotify_mkdir(d_inode(dentry->d_parent), dentry); + return end_creating(dentry); +} +EXPORT_SYMBOL_GPL(debugfs_create_dir); + +/** + * debugfs_create_automount - create automount point in the debugfs filesystem + * @name: a pointer to a string containing the name of the file to create. + * @parent: a pointer to the parent dentry for this file. This should be a + * directory dentry if set. If this parameter is NULL, then the + * file will be created in the root of the debugfs filesystem. + * @f: function to be called when pathname resolution steps on that one. + * @data: opaque argument to pass to f(). + * + * @f should return what ->d_automount() would. + */ +struct dentry *debugfs_create_automount(const char *name, + struct dentry *parent, + debugfs_automount_t f, + void *data) +{ + struct dentry *dentry = start_creating(name, parent); + struct debugfs_fsdata *fsd; + struct inode *inode; + + if (IS_ERR(dentry)) + return dentry; + + fsd = kzalloc(sizeof(*fsd), GFP_KERNEL); + if (!fsd) { + failed_creating(dentry); + return ERR_PTR(-ENOMEM); + } + + fsd->automount = f; + + if (!(debugfs_allow & DEBUGFS_ALLOW_API)) { + failed_creating(dentry); + kfree(fsd); + return ERR_PTR(-EPERM); + } + + inode = debugfs_get_inode(dentry->d_sb); + if (unlikely(!inode)) { + pr_err("out of free dentries, can not create automount '%s'\n", + name); + kfree(fsd); + return failed_creating(dentry); + } + + make_empty_dir_inode(inode); + inode->i_flags |= S_AUTOMOUNT; + inode->i_private = data; + dentry->d_fsdata = fsd; + /* directory inodes start off with i_nlink == 2 (for "." entry) */ + inc_nlink(inode); + d_instantiate(dentry, inode); + inc_nlink(d_inode(dentry->d_parent)); + fsnotify_mkdir(d_inode(dentry->d_parent), dentry); + return end_creating(dentry); +} +EXPORT_SYMBOL(debugfs_create_automount); + +/** + * debugfs_create_symlink- create a symbolic link in the debugfs filesystem + * @name: a pointer to a string containing the name of the symbolic link to + * create. + * @parent: a pointer to the parent dentry for this symbolic link. This + * should be a directory dentry if set. If this parameter is NULL, + * then the symbolic link will be created in the root of the debugfs + * filesystem. + * @target: a pointer to a string containing the path to the target of the + * symbolic link. + * + * This function creates a symbolic link with the given name in debugfs that + * links to the given target path. + * + * This function will return a pointer to a dentry if it succeeds. This + * pointer must be passed to the debugfs_remove() function when the symbolic + * link is to be removed (no automatic cleanup happens if your module is + * unloaded, you are responsible here.) If an error occurs, ERR_PTR(-ERROR) + * will be returned. + * + * If debugfs is not enabled in the kernel, the value -%ENODEV will be + * returned. + */ +struct dentry *debugfs_create_symlink(const char *name, struct dentry *parent, + const char *target) +{ + struct dentry *dentry; + struct inode *inode; + char *link = kstrdup(target, GFP_KERNEL); + if (!link) + return ERR_PTR(-ENOMEM); + + dentry = start_creating(name, parent); + if (IS_ERR(dentry)) { + kfree(link); + return dentry; + } + + inode = debugfs_get_inode(dentry->d_sb); + if (unlikely(!inode)) { + pr_err("out of free dentries, can not create symlink '%s'\n", + name); + kfree(link); + return failed_creating(dentry); + } + inode->i_mode = S_IFLNK | S_IRWXUGO; + inode->i_op = &debugfs_symlink_inode_operations; + inode->i_link = link; + d_instantiate(dentry, inode); + return end_creating(dentry); +} +EXPORT_SYMBOL_GPL(debugfs_create_symlink); + +static void __debugfs_file_removed(struct dentry *dentry) +{ + struct debugfs_fsdata *fsd; + + /* + * Paired with the closing smp_mb() implied by a successful + * cmpxchg() in debugfs_file_get(): either + * debugfs_file_get() must see a dead dentry or we must see a + * debugfs_fsdata instance at ->d_fsdata here (or both). + */ + smp_mb(); + fsd = READ_ONCE(dentry->d_fsdata); + if ((unsigned long)fsd & DEBUGFS_FSDATA_IS_REAL_FOPS_BIT) + return; + if (!refcount_dec_and_test(&fsd->active_users)) + wait_for_completion(&fsd->active_users_drained); +} + +static void remove_one(struct dentry *victim) +{ + if (d_is_reg(victim)) + __debugfs_file_removed(victim); + simple_release_fs(&debugfs_mount, &debugfs_mount_count); +} + +/** + * debugfs_remove - recursively removes a directory + * @dentry: a pointer to a the dentry of the directory to be removed. If this + * parameter is NULL or an error value, nothing will be done. + * + * This function recursively removes a directory tree in debugfs that + * was previously created with a call to another debugfs function + * (like debugfs_create_file() or variants thereof.) + * + * This function is required to be called in order for the file to be + * removed, no automatic cleanup of files will happen when a module is + * removed, you are responsible here. + */ +void debugfs_remove(struct dentry *dentry) +{ + if (IS_ERR_OR_NULL(dentry)) + return; + + simple_pin_fs(&debug_fs_type, &debugfs_mount, &debugfs_mount_count); + simple_recursive_removal(dentry, remove_one); + simple_release_fs(&debugfs_mount, &debugfs_mount_count); +} +EXPORT_SYMBOL_GPL(debugfs_remove); + +/** + * debugfs_lookup_and_remove - lookup a directory or file and recursively remove it + * @name: a pointer to a string containing the name of the item to look up. + * @parent: a pointer to the parent dentry of the item. + * + * This is the equlivant of doing something like + * debugfs_remove(debugfs_lookup(..)) but with the proper reference counting + * handled for the directory being looked up. + */ +void debugfs_lookup_and_remove(const char *name, struct dentry *parent) +{ + struct dentry *dentry; + + dentry = debugfs_lookup(name, parent); + if (!dentry) + return; + + debugfs_remove(dentry); + dput(dentry); +} +EXPORT_SYMBOL_GPL(debugfs_lookup_and_remove); + +/** + * debugfs_rename - rename a file/directory in the debugfs filesystem + * @old_dir: a pointer to the parent dentry for the renamed object. This + * should be a directory dentry. + * @old_dentry: dentry of an object to be renamed. + * @new_dir: a pointer to the parent dentry where the object should be + * moved. This should be a directory dentry. + * @new_name: a pointer to a string containing the target name. + * + * This function renames a file/directory in debugfs. The target must not + * exist for rename to succeed. + * + * This function will return a pointer to old_dentry (which is updated to + * reflect renaming) if it succeeds. If an error occurs, %NULL will be + * returned. + * + * If debugfs is not enabled in the kernel, the value -%ENODEV will be + * returned. + */ +struct dentry *debugfs_rename(struct dentry *old_dir, struct dentry *old_dentry, + struct dentry *new_dir, const char *new_name) +{ + int error; + struct dentry *dentry = NULL, *trap; + struct name_snapshot old_name; + + if (IS_ERR(old_dir)) + return old_dir; + if (IS_ERR(new_dir)) + return new_dir; + if (IS_ERR_OR_NULL(old_dentry)) + return old_dentry; + + trap = lock_rename(new_dir, old_dir); + /* Source or destination directories don't exist? */ + if (d_really_is_negative(old_dir) || d_really_is_negative(new_dir)) + goto exit; + /* Source does not exist, cyclic rename, or mountpoint? */ + if (d_really_is_negative(old_dentry) || old_dentry == trap || + d_mountpoint(old_dentry)) + goto exit; + dentry = lookup_one_len(new_name, new_dir, strlen(new_name)); + /* Lookup failed, cyclic rename or target exists? */ + if (IS_ERR(dentry) || dentry == trap || d_really_is_positive(dentry)) + goto exit; + + take_dentry_name_snapshot(&old_name, old_dentry); + + error = simple_rename(d_inode(old_dir), old_dentry, d_inode(new_dir), + dentry, 0); + if (error) { + release_dentry_name_snapshot(&old_name); + goto exit; + } + d_move(old_dentry, dentry); + fsnotify_move(d_inode(old_dir), d_inode(new_dir), &old_name.name, + d_is_dir(old_dentry), + NULL, old_dentry); + release_dentry_name_snapshot(&old_name); + unlock_rename(new_dir, old_dir); + dput(dentry); + return old_dentry; +exit: + if (dentry && !IS_ERR(dentry)) + dput(dentry); + unlock_rename(new_dir, old_dir); + if (IS_ERR(dentry)) + return dentry; + return ERR_PTR(-EINVAL); +} +EXPORT_SYMBOL_GPL(debugfs_rename); + +/** + * debugfs_initialized - Tells whether debugfs has been registered + */ +bool debugfs_initialized(void) +{ + return debugfs_registered; +} +EXPORT_SYMBOL_GPL(debugfs_initialized); + +static int __init debugfs_kernel(char *str) +{ + if (str) { + if (!strcmp(str, "on")) + debugfs_allow = DEBUGFS_ALLOW_API | DEBUGFS_ALLOW_MOUNT; + else if (!strcmp(str, "no-mount")) + debugfs_allow = DEBUGFS_ALLOW_API; + else if (!strcmp(str, "off")) + debugfs_allow = 0; + } + + return 0; +} +early_param("debugfs", debugfs_kernel); +static int __init debugfs_init(void) +{ + int retval; + + if (!(debugfs_allow & DEBUGFS_ALLOW_MOUNT)) + return -EPERM; + + retval = sysfs_create_mount_point(kernel_kobj, "debug"); + if (retval) + return retval; + + retval = register_filesystem(&debug_fs_type); + if (retval) + sysfs_remove_mount_point(kernel_kobj, "debug"); + else + debugfs_registered = true; + + return retval; +} +core_initcall(debugfs_init); diff --git a/fs/debugfs/internal.h b/fs/debugfs/internal.h new file mode 100644 index 000000000..f7c489b5a --- /dev/null +++ b/fs/debugfs/internal.h @@ -0,0 +1,52 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * internal.h - declarations internal to debugfs + * + * Copyright (C) 2016 Nicolai Stange <nicstange@gmail.com> + */ + +#ifndef _DEBUGFS_INTERNAL_H_ +#define _DEBUGFS_INTERNAL_H_ + +struct file_operations; + +/* 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; + +struct debugfs_fsdata { + const struct file_operations *real_fops; + union { + /* automount_fn is used when real_fops is NULL */ + debugfs_automount_t automount; + struct { + refcount_t active_users; + struct completion active_users_drained; + }; + }; +}; + +/* + * A dentry's ->d_fsdata either points to the real fops or to a + * dynamically allocated debugfs_fsdata instance. + * In order to distinguish between these two cases, a real fops + * pointer gets its lowest bit set. + */ +#define DEBUGFS_FSDATA_IS_REAL_FOPS_BIT BIT(0) + +/* Access BITS */ +#define DEBUGFS_ALLOW_API BIT(0) +#define DEBUGFS_ALLOW_MOUNT BIT(1) + +#ifdef CONFIG_DEBUG_FS_ALLOW_ALL +#define DEFAULT_DEBUGFS_ALLOW_BITS (DEBUGFS_ALLOW_MOUNT | DEBUGFS_ALLOW_API) +#endif +#ifdef CONFIG_DEBUG_FS_DISALLOW_MOUNT +#define DEFAULT_DEBUGFS_ALLOW_BITS (DEBUGFS_ALLOW_API) +#endif +#ifdef CONFIG_DEBUG_FS_ALLOW_NONE +#define DEFAULT_DEBUGFS_ALLOW_BITS (0) +#endif + +#endif /* _DEBUGFS_INTERNAL_H_ */ |