// 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 user_namespace *mnt_userns, struct dentry *dentry, struct iattr *ia){ int ret; if (ia->ia_valid & (ATTR_MODE | ATTR_UID | ATTR_GID)) { ret = security_locked_down(LOCKDOWN_DEBUGFS); if (ret) return ret; } return simple_setattr(&init_user_ns, 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; /* Opt_* bitfield. */ unsigned int opts;}; 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->opts = 0; 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 */ } opts->opts |= BIT(token); } return 0;} static void _debugfs_apply_options(struct super_block *sb, bool remount){ 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; /* * On remount, only reset mode/uid/gid if they were provided as mount * options. */ if (!remount || opts->opts & BIT(Opt_mode)) { inode->i_mode &= ~S_IALLUGO; inode->i_mode |= opts->mode; } if (!remount || opts->opts & BIT(Opt_uid)) inode->i_uid = opts->uid; if (!remount || opts->opts & BIT(Opt_gid)) inode->i_gid = opts->gid;} static void debugfs_apply_options(struct super_block *sb){ _debugfs_apply_options(sb, false);} static void debugfs_apply_options_remount(struct super_block *sb){ _debugfs_apply_options(sb, true);} 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_remount(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){ void *fsd = dentry->d_fsdata; if (!((unsigned long)fsd & DEBUGFS_FSDATA_IS_REAL_FOPS_BIT)) kfree(dentry->d_fsdata);} static struct vfsmount *debugfs_automount(struct path *path){ debugfs_automount_t f; f = (debugfs_automount_t)path->dentry->d_fsdata; return f(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. * * NOTE: it's expected that most callers should _ignore_ the errors returned * by this function. Other debugfs functions handle the fact that the "dentry" * passed to them could be an error and they don't crash in that case. * Drivers should generally work fine even if debugfs fails to init anyway. */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.Lines 1–500 of 906. Load more
// 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 user_namespace *mnt_userns, struct dentry *dentry, struct iattr *ia) { int ret; if (ia->ia_valid & (ATTR_MODE | ATTR_UID | ATTR_GID)) { ret = security_locked_down(LOCKDOWN_DEBUGFS); if (ret) return ret; } return simple_setattr(&init_user_ns, 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; /* Opt_* bitfield. */ unsigned int opts; }; 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->opts = 0; 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 */ } opts->opts |= BIT(token); } return 0; } static void _debugfs_apply_options(struct super_block *sb, bool remount) { 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; /* * On remount, only reset mode/uid/gid if they were provided as mount * options. */ if (!remount || opts->opts & BIT(Opt_mode)) { inode->i_mode &= ~S_IALLUGO; inode->i_mode |= opts->mode; } if (!remount || opts->opts & BIT(Opt_uid)) inode->i_uid = opts->uid; if (!remount || opts->opts & BIT(Opt_gid)) inode->i_gid = opts->gid; } static void debugfs_apply_options(struct super_block *sb) { _debugfs_apply_options(sb, false); } static void debugfs_apply_options_remount(struct super_block *sb) { _debugfs_apply_options(sb, true); } 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_remount(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) { void *fsd = dentry->d_fsdata; if (!((unsigned long)fsd & DEBUGFS_FSDATA_IS_REAL_FOPS_BIT)) kfree(dentry->d_fsdata); } static struct vfsmount *debugfs_automount(struct path *path) { debugfs_automount_t f; f = (debugfs_automount_t)path->dentry->d_fsdata; return f(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. * * NOTE: it's expected that most callers should _ignore_ the errors returned * by this function. Other debugfs functions handle the fact that the "dentry" * passed to them could be an error and they don't crash in that case. * Drivers should generally work fine even if debugfs fails to init anyway. */ 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.