v4.19.13 snapshot.
diff --git a/fs/proc/generic.c b/fs/proc/generic.c
new file mode 100644
index 0000000..8ae1094
--- /dev/null
+++ b/fs/proc/generic.c
@@ -0,0 +1,775 @@
+/*
+ * proc/fs/generic.c --- generic routines for the proc-fs
+ *
+ * This file contains generic proc-fs routines for handling
+ * directories and files.
+ *
+ * Copyright (C) 1991, 1992 Linus Torvalds.
+ * Copyright (C) 1997 Theodore Ts'o
+ */
+
+#include <linux/cache.h>
+#include <linux/errno.h>
+#include <linux/time.h>
+#include <linux/proc_fs.h>
+#include <linux/stat.h>
+#include <linux/mm.h>
+#include <linux/module.h>
+#include <linux/namei.h>
+#include <linux/slab.h>
+#include <linux/printk.h>
+#include <linux/mount.h>
+#include <linux/init.h>
+#include <linux/idr.h>
+#include <linux/bitops.h>
+#include <linux/spinlock.h>
+#include <linux/completion.h>
+#include <linux/uaccess.h>
+#include <linux/seq_file.h>
+
+#include "internal.h"
+
+static DEFINE_RWLOCK(proc_subdir_lock);
+
+struct kmem_cache *proc_dir_entry_cache __ro_after_init;
+
+void pde_free(struct proc_dir_entry *pde)
+{
+ if (S_ISLNK(pde->mode))
+ kfree(pde->data);
+ if (pde->name != pde->inline_name)
+ kfree(pde->name);
+ kmem_cache_free(proc_dir_entry_cache, pde);
+}
+
+static int proc_match(const char *name, struct proc_dir_entry *de, unsigned int len)
+{
+ if (len < de->namelen)
+ return -1;
+ if (len > de->namelen)
+ return 1;
+
+ return memcmp(name, de->name, len);
+}
+
+static struct proc_dir_entry *pde_subdir_first(struct proc_dir_entry *dir)
+{
+ return rb_entry_safe(rb_first(&dir->subdir), struct proc_dir_entry,
+ subdir_node);
+}
+
+static struct proc_dir_entry *pde_subdir_next(struct proc_dir_entry *dir)
+{
+ return rb_entry_safe(rb_next(&dir->subdir_node), struct proc_dir_entry,
+ subdir_node);
+}
+
+static struct proc_dir_entry *pde_subdir_find(struct proc_dir_entry *dir,
+ const char *name,
+ unsigned int len)
+{
+ struct rb_node *node = dir->subdir.rb_node;
+
+ while (node) {
+ struct proc_dir_entry *de = rb_entry(node,
+ struct proc_dir_entry,
+ subdir_node);
+ int result = proc_match(name, de, len);
+
+ if (result < 0)
+ node = node->rb_left;
+ else if (result > 0)
+ node = node->rb_right;
+ else
+ return de;
+ }
+ return NULL;
+}
+
+static bool pde_subdir_insert(struct proc_dir_entry *dir,
+ struct proc_dir_entry *de)
+{
+ struct rb_root *root = &dir->subdir;
+ struct rb_node **new = &root->rb_node, *parent = NULL;
+
+ /* Figure out where to put new node */
+ while (*new) {
+ struct proc_dir_entry *this = rb_entry(*new,
+ struct proc_dir_entry,
+ subdir_node);
+ int result = proc_match(de->name, this, de->namelen);
+
+ parent = *new;
+ if (result < 0)
+ new = &(*new)->rb_left;
+ else if (result > 0)
+ new = &(*new)->rb_right;
+ else
+ return false;
+ }
+
+ /* Add new node and rebalance tree. */
+ rb_link_node(&de->subdir_node, parent, new);
+ rb_insert_color(&de->subdir_node, root);
+ return true;
+}
+
+static int proc_notify_change(struct dentry *dentry, struct iattr *iattr)
+{
+ struct inode *inode = d_inode(dentry);
+ struct proc_dir_entry *de = PDE(inode);
+ int error;
+
+ error = setattr_prepare(dentry, iattr);
+ if (error)
+ return error;
+
+ setattr_copy(inode, iattr);
+ mark_inode_dirty(inode);
+
+ proc_set_user(de, inode->i_uid, inode->i_gid);
+ de->mode = inode->i_mode;
+ return 0;
+}
+
+static int proc_getattr(const struct path *path, struct kstat *stat,
+ u32 request_mask, unsigned int query_flags)
+{
+ struct inode *inode = d_inode(path->dentry);
+ struct proc_dir_entry *de = PDE(inode);
+ if (de && de->nlink)
+ set_nlink(inode, de->nlink);
+
+ generic_fillattr(inode, stat);
+ return 0;
+}
+
+static const struct inode_operations proc_file_inode_operations = {
+ .setattr = proc_notify_change,
+};
+
+/*
+ * This function parses a name such as "tty/driver/serial", and
+ * returns the struct proc_dir_entry for "/proc/tty/driver", and
+ * returns "serial" in residual.
+ */
+static int __xlate_proc_name(const char *name, struct proc_dir_entry **ret,
+ const char **residual)
+{
+ const char *cp = name, *next;
+ struct proc_dir_entry *de;
+ unsigned int len;
+
+ de = *ret;
+ if (!de)
+ de = &proc_root;
+
+ while (1) {
+ next = strchr(cp, '/');
+ if (!next)
+ break;
+
+ len = next - cp;
+ de = pde_subdir_find(de, cp, len);
+ if (!de) {
+ WARN(1, "name '%s'\n", name);
+ return -ENOENT;
+ }
+ cp += len + 1;
+ }
+ *residual = cp;
+ *ret = de;
+ return 0;
+}
+
+static int xlate_proc_name(const char *name, struct proc_dir_entry **ret,
+ const char **residual)
+{
+ int rv;
+
+ read_lock(&proc_subdir_lock);
+ rv = __xlate_proc_name(name, ret, residual);
+ read_unlock(&proc_subdir_lock);
+ return rv;
+}
+
+static DEFINE_IDA(proc_inum_ida);
+
+#define PROC_DYNAMIC_FIRST 0xF0000000U
+
+/*
+ * Return an inode number between PROC_DYNAMIC_FIRST and
+ * 0xffffffff, or zero on failure.
+ */
+int proc_alloc_inum(unsigned int *inum)
+{
+ int i;
+
+ i = ida_simple_get(&proc_inum_ida, 0, UINT_MAX - PROC_DYNAMIC_FIRST + 1,
+ GFP_KERNEL);
+ if (i < 0)
+ return i;
+
+ *inum = PROC_DYNAMIC_FIRST + (unsigned int)i;
+ return 0;
+}
+
+void proc_free_inum(unsigned int inum)
+{
+ ida_simple_remove(&proc_inum_ida, inum - PROC_DYNAMIC_FIRST);
+}
+
+static int proc_misc_d_revalidate(struct dentry *dentry, unsigned int flags)
+{
+ if (flags & LOOKUP_RCU)
+ return -ECHILD;
+
+ if (atomic_read(&PDE(d_inode(dentry))->in_use) < 0)
+ return 0; /* revalidate */
+ return 1;
+}
+
+static int proc_misc_d_delete(const struct dentry *dentry)
+{
+ return atomic_read(&PDE(d_inode(dentry))->in_use) < 0;
+}
+
+static const struct dentry_operations proc_misc_dentry_ops = {
+ .d_revalidate = proc_misc_d_revalidate,
+ .d_delete = proc_misc_d_delete,
+};
+
+/*
+ * Don't create negative dentries here, return -ENOENT by hand
+ * instead.
+ */
+struct dentry *proc_lookup_de(struct inode *dir, struct dentry *dentry,
+ struct proc_dir_entry *de)
+{
+ struct inode *inode;
+
+ read_lock(&proc_subdir_lock);
+ de = pde_subdir_find(de, dentry->d_name.name, dentry->d_name.len);
+ if (de) {
+ pde_get(de);
+ read_unlock(&proc_subdir_lock);
+ inode = proc_get_inode(dir->i_sb, de);
+ if (!inode)
+ return ERR_PTR(-ENOMEM);
+ d_set_d_op(dentry, &proc_misc_dentry_ops);
+ return d_splice_alias(inode, dentry);
+ }
+ read_unlock(&proc_subdir_lock);
+ return ERR_PTR(-ENOENT);
+}
+
+struct dentry *proc_lookup(struct inode *dir, struct dentry *dentry,
+ unsigned int flags)
+{
+ return proc_lookup_de(dir, dentry, PDE(dir));
+}
+
+/*
+ * This returns non-zero if at EOF, so that the /proc
+ * root directory can use this and check if it should
+ * continue with the <pid> entries..
+ *
+ * Note that the VFS-layer doesn't care about the return
+ * value of the readdir() call, as long as it's non-negative
+ * for success..
+ */
+int proc_readdir_de(struct file *file, struct dir_context *ctx,
+ struct proc_dir_entry *de)
+{
+ int i;
+
+ if (!dir_emit_dots(file, ctx))
+ return 0;
+
+ i = ctx->pos - 2;
+ read_lock(&proc_subdir_lock);
+ de = pde_subdir_first(de);
+ for (;;) {
+ if (!de) {
+ read_unlock(&proc_subdir_lock);
+ return 0;
+ }
+ if (!i)
+ break;
+ de = pde_subdir_next(de);
+ i--;
+ }
+
+ do {
+ struct proc_dir_entry *next;
+ pde_get(de);
+ read_unlock(&proc_subdir_lock);
+ if (!dir_emit(ctx, de->name, de->namelen,
+ de->low_ino, de->mode >> 12)) {
+ pde_put(de);
+ return 0;
+ }
+ ctx->pos++;
+ read_lock(&proc_subdir_lock);
+ next = pde_subdir_next(de);
+ pde_put(de);
+ de = next;
+ } while (de);
+ read_unlock(&proc_subdir_lock);
+ return 1;
+}
+
+int proc_readdir(struct file *file, struct dir_context *ctx)
+{
+ struct inode *inode = file_inode(file);
+
+ return proc_readdir_de(file, ctx, PDE(inode));
+}
+
+/*
+ * These are the generic /proc directory operations. They
+ * use the in-memory "struct proc_dir_entry" tree to parse
+ * the /proc directory.
+ */
+static const struct file_operations proc_dir_operations = {
+ .llseek = generic_file_llseek,
+ .read = generic_read_dir,
+ .iterate_shared = proc_readdir,
+};
+
+/*
+ * proc directories can do almost nothing..
+ */
+static const struct inode_operations proc_dir_inode_operations = {
+ .lookup = proc_lookup,
+ .getattr = proc_getattr,
+ .setattr = proc_notify_change,
+};
+
+/* returns the registered entry, or frees dp and returns NULL on failure */
+struct proc_dir_entry *proc_register(struct proc_dir_entry *dir,
+ struct proc_dir_entry *dp)
+{
+ if (proc_alloc_inum(&dp->low_ino))
+ goto out_free_entry;
+
+ write_lock(&proc_subdir_lock);
+ dp->parent = dir;
+ if (pde_subdir_insert(dir, dp) == false) {
+ WARN(1, "proc_dir_entry '%s/%s' already registered\n",
+ dir->name, dp->name);
+ write_unlock(&proc_subdir_lock);
+ goto out_free_inum;
+ }
+ write_unlock(&proc_subdir_lock);
+
+ return dp;
+out_free_inum:
+ proc_free_inum(dp->low_ino);
+out_free_entry:
+ pde_free(dp);
+ return NULL;
+}
+
+static struct proc_dir_entry *__proc_create(struct proc_dir_entry **parent,
+ const char *name,
+ umode_t mode,
+ nlink_t nlink)
+{
+ struct proc_dir_entry *ent = NULL;
+ const char *fn;
+ struct qstr qstr;
+
+ if (xlate_proc_name(name, parent, &fn) != 0)
+ goto out;
+ qstr.name = fn;
+ qstr.len = strlen(fn);
+ if (qstr.len == 0 || qstr.len >= 256) {
+ WARN(1, "name len %u\n", qstr.len);
+ return NULL;
+ }
+ if (qstr.len == 1 && fn[0] == '.') {
+ WARN(1, "name '.'\n");
+ return NULL;
+ }
+ if (qstr.len == 2 && fn[0] == '.' && fn[1] == '.') {
+ WARN(1, "name '..'\n");
+ return NULL;
+ }
+ if (*parent == &proc_root && name_to_int(&qstr) != ~0U) {
+ WARN(1, "create '/proc/%s' by hand\n", qstr.name);
+ return NULL;
+ }
+ if (is_empty_pde(*parent)) {
+ WARN(1, "attempt to add to permanently empty directory");
+ return NULL;
+ }
+
+ ent = kmem_cache_zalloc(proc_dir_entry_cache, GFP_KERNEL);
+ if (!ent)
+ goto out;
+
+ if (qstr.len + 1 <= SIZEOF_PDE_INLINE_NAME) {
+ ent->name = ent->inline_name;
+ } else {
+ ent->name = kmalloc(qstr.len + 1, GFP_KERNEL);
+ if (!ent->name) {
+ pde_free(ent);
+ return NULL;
+ }
+ }
+
+ memcpy(ent->name, fn, qstr.len + 1);
+ ent->namelen = qstr.len;
+ ent->mode = mode;
+ ent->nlink = nlink;
+ ent->subdir = RB_ROOT;
+ refcount_set(&ent->refcnt, 1);
+ spin_lock_init(&ent->pde_unload_lock);
+ INIT_LIST_HEAD(&ent->pde_openers);
+ proc_set_user(ent, (*parent)->uid, (*parent)->gid);
+
+out:
+ return ent;
+}
+
+struct proc_dir_entry *proc_symlink(const char *name,
+ struct proc_dir_entry *parent, const char *dest)
+{
+ struct proc_dir_entry *ent;
+
+ ent = __proc_create(&parent, name,
+ (S_IFLNK | S_IRUGO | S_IWUGO | S_IXUGO),1);
+
+ if (ent) {
+ ent->data = kmalloc((ent->size=strlen(dest))+1, GFP_KERNEL);
+ if (ent->data) {
+ strcpy((char*)ent->data,dest);
+ ent->proc_iops = &proc_link_inode_operations;
+ ent = proc_register(parent, ent);
+ } else {
+ pde_free(ent);
+ ent = NULL;
+ }
+ }
+ return ent;
+}
+EXPORT_SYMBOL(proc_symlink);
+
+struct proc_dir_entry *proc_mkdir_data(const char *name, umode_t mode,
+ struct proc_dir_entry *parent, void *data)
+{
+ struct proc_dir_entry *ent;
+
+ if (mode == 0)
+ mode = S_IRUGO | S_IXUGO;
+
+ ent = __proc_create(&parent, name, S_IFDIR | mode, 2);
+ if (ent) {
+ ent->data = data;
+ ent->proc_fops = &proc_dir_operations;
+ ent->proc_iops = &proc_dir_inode_operations;
+ parent->nlink++;
+ ent = proc_register(parent, ent);
+ if (!ent)
+ parent->nlink--;
+ }
+ return ent;
+}
+EXPORT_SYMBOL_GPL(proc_mkdir_data);
+
+struct proc_dir_entry *proc_mkdir_mode(const char *name, umode_t mode,
+ struct proc_dir_entry *parent)
+{
+ return proc_mkdir_data(name, mode, parent, NULL);
+}
+EXPORT_SYMBOL(proc_mkdir_mode);
+
+struct proc_dir_entry *proc_mkdir(const char *name,
+ struct proc_dir_entry *parent)
+{
+ return proc_mkdir_data(name, 0, parent, NULL);
+}
+EXPORT_SYMBOL(proc_mkdir);
+
+struct proc_dir_entry *proc_create_mount_point(const char *name)
+{
+ umode_t mode = S_IFDIR | S_IRUGO | S_IXUGO;
+ struct proc_dir_entry *ent, *parent = NULL;
+
+ ent = __proc_create(&parent, name, mode, 2);
+ if (ent) {
+ ent->data = NULL;
+ ent->proc_fops = NULL;
+ ent->proc_iops = NULL;
+ parent->nlink++;
+ ent = proc_register(parent, ent);
+ if (!ent)
+ parent->nlink--;
+ }
+ return ent;
+}
+EXPORT_SYMBOL(proc_create_mount_point);
+
+struct proc_dir_entry *proc_create_reg(const char *name, umode_t mode,
+ struct proc_dir_entry **parent, void *data)
+{
+ struct proc_dir_entry *p;
+
+ if ((mode & S_IFMT) == 0)
+ mode |= S_IFREG;
+ if ((mode & S_IALLUGO) == 0)
+ mode |= S_IRUGO;
+ if (WARN_ON_ONCE(!S_ISREG(mode)))
+ return NULL;
+
+ p = __proc_create(parent, name, mode, 1);
+ if (p) {
+ p->proc_iops = &proc_file_inode_operations;
+ p->data = data;
+ }
+ return p;
+}
+
+struct proc_dir_entry *proc_create_data(const char *name, umode_t mode,
+ struct proc_dir_entry *parent,
+ const struct file_operations *proc_fops, void *data)
+{
+ struct proc_dir_entry *p;
+
+ BUG_ON(proc_fops == NULL);
+
+ p = proc_create_reg(name, mode, &parent, data);
+ if (!p)
+ return NULL;
+ p->proc_fops = proc_fops;
+ return proc_register(parent, p);
+}
+EXPORT_SYMBOL(proc_create_data);
+
+struct proc_dir_entry *proc_create(const char *name, umode_t mode,
+ struct proc_dir_entry *parent,
+ const struct file_operations *proc_fops)
+{
+ return proc_create_data(name, mode, parent, proc_fops, NULL);
+}
+EXPORT_SYMBOL(proc_create);
+
+static int proc_seq_open(struct inode *inode, struct file *file)
+{
+ struct proc_dir_entry *de = PDE(inode);
+
+ if (de->state_size)
+ return seq_open_private(file, de->seq_ops, de->state_size);
+ return seq_open(file, de->seq_ops);
+}
+
+static int proc_seq_release(struct inode *inode, struct file *file)
+{
+ struct proc_dir_entry *de = PDE(inode);
+
+ if (de->state_size)
+ return seq_release_private(inode, file);
+ return seq_release(inode, file);
+}
+
+static const struct file_operations proc_seq_fops = {
+ .open = proc_seq_open,
+ .read = seq_read,
+ .llseek = seq_lseek,
+ .release = proc_seq_release,
+};
+
+struct proc_dir_entry *proc_create_seq_private(const char *name, umode_t mode,
+ struct proc_dir_entry *parent, const struct seq_operations *ops,
+ unsigned int state_size, void *data)
+{
+ struct proc_dir_entry *p;
+
+ p = proc_create_reg(name, mode, &parent, data);
+ if (!p)
+ return NULL;
+ p->proc_fops = &proc_seq_fops;
+ p->seq_ops = ops;
+ p->state_size = state_size;
+ return proc_register(parent, p);
+}
+EXPORT_SYMBOL(proc_create_seq_private);
+
+static int proc_single_open(struct inode *inode, struct file *file)
+{
+ struct proc_dir_entry *de = PDE(inode);
+
+ return single_open(file, de->single_show, de->data);
+}
+
+static const struct file_operations proc_single_fops = {
+ .open = proc_single_open,
+ .read = seq_read,
+ .llseek = seq_lseek,
+ .release = single_release,
+};
+
+struct proc_dir_entry *proc_create_single_data(const char *name, umode_t mode,
+ struct proc_dir_entry *parent,
+ int (*show)(struct seq_file *, void *), void *data)
+{
+ struct proc_dir_entry *p;
+
+ p = proc_create_reg(name, mode, &parent, data);
+ if (!p)
+ return NULL;
+ p->proc_fops = &proc_single_fops;
+ p->single_show = show;
+ return proc_register(parent, p);
+}
+EXPORT_SYMBOL(proc_create_single_data);
+
+void proc_set_size(struct proc_dir_entry *de, loff_t size)
+{
+ de->size = size;
+}
+EXPORT_SYMBOL(proc_set_size);
+
+void proc_set_user(struct proc_dir_entry *de, kuid_t uid, kgid_t gid)
+{
+ de->uid = uid;
+ de->gid = gid;
+}
+EXPORT_SYMBOL(proc_set_user);
+
+void pde_put(struct proc_dir_entry *pde)
+{
+ if (refcount_dec_and_test(&pde->refcnt)) {
+ proc_free_inum(pde->low_ino);
+ pde_free(pde);
+ }
+}
+
+/*
+ * Remove a /proc entry and free it if it's not currently in use.
+ */
+void remove_proc_entry(const char *name, struct proc_dir_entry *parent)
+{
+ struct proc_dir_entry *de = NULL;
+ const char *fn = name;
+ unsigned int len;
+
+ write_lock(&proc_subdir_lock);
+ if (__xlate_proc_name(name, &parent, &fn) != 0) {
+ write_unlock(&proc_subdir_lock);
+ return;
+ }
+ len = strlen(fn);
+
+ de = pde_subdir_find(parent, fn, len);
+ if (de)
+ rb_erase(&de->subdir_node, &parent->subdir);
+ write_unlock(&proc_subdir_lock);
+ if (!de) {
+ WARN(1, "name '%s'\n", name);
+ return;
+ }
+
+ proc_entry_rundown(de);
+
+ if (S_ISDIR(de->mode))
+ parent->nlink--;
+ de->nlink = 0;
+ WARN(pde_subdir_first(de),
+ "%s: removing non-empty directory '%s/%s', leaking at least '%s'\n",
+ __func__, de->parent->name, de->name, pde_subdir_first(de)->name);
+ pde_put(de);
+}
+EXPORT_SYMBOL(remove_proc_entry);
+
+int remove_proc_subtree(const char *name, struct proc_dir_entry *parent)
+{
+ struct proc_dir_entry *root = NULL, *de, *next;
+ const char *fn = name;
+ unsigned int len;
+
+ write_lock(&proc_subdir_lock);
+ if (__xlate_proc_name(name, &parent, &fn) != 0) {
+ write_unlock(&proc_subdir_lock);
+ return -ENOENT;
+ }
+ len = strlen(fn);
+
+ root = pde_subdir_find(parent, fn, len);
+ if (!root) {
+ write_unlock(&proc_subdir_lock);
+ return -ENOENT;
+ }
+ rb_erase(&root->subdir_node, &parent->subdir);
+
+ de = root;
+ while (1) {
+ next = pde_subdir_first(de);
+ if (next) {
+ rb_erase(&next->subdir_node, &de->subdir);
+ de = next;
+ continue;
+ }
+ write_unlock(&proc_subdir_lock);
+
+ proc_entry_rundown(de);
+ next = de->parent;
+ if (S_ISDIR(de->mode))
+ next->nlink--;
+ de->nlink = 0;
+ if (de == root)
+ break;
+ pde_put(de);
+
+ write_lock(&proc_subdir_lock);
+ de = next;
+ }
+ pde_put(root);
+ return 0;
+}
+EXPORT_SYMBOL(remove_proc_subtree);
+
+void *proc_get_parent_data(const struct inode *inode)
+{
+ struct proc_dir_entry *de = PDE(inode);
+ return de->parent->data;
+}
+EXPORT_SYMBOL_GPL(proc_get_parent_data);
+
+void proc_remove(struct proc_dir_entry *de)
+{
+ if (de)
+ remove_proc_subtree(de->name, de->parent);
+}
+EXPORT_SYMBOL(proc_remove);
+
+void *PDE_DATA(const struct inode *inode)
+{
+ return __PDE_DATA(inode);
+}
+EXPORT_SYMBOL(PDE_DATA);
+
+/*
+ * Pull a user buffer into memory and pass it to the file's write handler if
+ * one is supplied. The ->write() method is permitted to modify the
+ * kernel-side buffer.
+ */
+ssize_t proc_simple_write(struct file *f, const char __user *ubuf, size_t size,
+ loff_t *_pos)
+{
+ struct proc_dir_entry *pde = PDE(file_inode(f));
+ char *buf;
+ int ret;
+
+ if (!pde->write)
+ return -EACCES;
+ if (size == 0 || size > PAGE_SIZE - 1)
+ return -EINVAL;
+ buf = memdup_user_nul(ubuf, size);
+ if (IS_ERR(buf))
+ return PTR_ERR(buf);
+ ret = pde->write(f, buf, size);
+ kfree(buf);
+ return ret == 0 ? size : ret;
+}