#include <linux/kdev_t.h>
#include <linux/kernel.h>
#include <linux/list.h>
+#include <linux/namei.h>
#include <linux/magic.h>
#include <linux/major.h>
#include <linux/miscdevice.h>
#include <linux/parser.h>
#include <linux/radix-tree.h>
#include <linux/sched.h>
+#include <linux/seq_file.h>
#include <linux/slab.h>
#include <linux/spinlock_types.h>
#include <linux/stddef.h>
#include <linux/xarray.h>
#include <uapi/asm-generic/errno-base.h>
#include <uapi/linux/android/binder.h>
-#include <uapi/linux/android/binder_ctl.h>
+#include <uapi/linux/android/binderfs.h>
#include "binder_internal.h"
#define INODE_OFFSET 3
#define INTSTRLEN 21
#define BINDERFS_MAX_MINOR (1U << MINORBITS)
-
-static struct vfsmount *binderfs_mnt;
+/* Ensure that the initial ipc namespace always has devices available. */
+#define BINDERFS_MAX_MINOR_CAPPED (BINDERFS_MAX_MINOR - 4)
static dev_t binderfs_dev;
static DEFINE_MUTEX(binderfs_minors_mutex);
static DEFINE_IDA(binderfs_minors);
+/**
+ * binderfs_mount_opts - mount options for binderfs
+ * @max: maximum number of allocatable binderfs binder devices
+ */
+struct binderfs_mount_opts {
+ int max;
+};
+
+enum {
+ Opt_max,
+ Opt_err
+};
+
+static const match_table_t tokens = {
+ { Opt_max, "max=%d" },
+ { Opt_err, NULL }
+};
+
/**
* binderfs_info - information about a binderfs mount
* @ipc_ns: The ipc namespace the binderfs mount belongs to.
* created.
* @root_gid: gid that needs to be used when a new binder device is
* created.
+ * @mount_opts: The mount options in use.
+ * @device_count: The current number of allocated binder devices.
*/
struct binderfs_info {
struct ipc_namespace *ipc_ns;
struct dentry *control_dentry;
kuid_t root_uid;
kgid_t root_gid;
-
+ struct binderfs_mount_opts mount_opts;
+ int device_count;
};
static inline struct binderfs_info *BINDERFS_I(const struct inode *inode)
* @userp: buffer to copy information about new device for userspace to
* @req: struct binderfs_device as copied from userspace
*
- * This function allocated a new binder_device and reserves a new minor
+ * This function allocates a new binder_device and reserves a new minor
* number for it.
* Minor numbers are limited and tracked globally in binderfs_minors. The
* function will stash a struct binder_device for the specific binder
struct binderfs_device *req)
{
int minor, ret;
- struct dentry *dentry, *dup, *root;
+ struct dentry *dentry, *root;
struct binder_device *device;
- size_t name_len = BINDERFS_MAX_NAME + 1;
char *name = NULL;
+ size_t name_len;
struct inode *inode = NULL;
struct super_block *sb = ref_inode->i_sb;
struct binderfs_info *info = sb->s_fs_info;
+#if defined(CONFIG_IPC_NS)
+ bool use_reserve = (info->ipc_ns == &init_ipc_ns);
+#else
+ bool use_reserve = true;
+#endif
/* Reserve new minor number for the new device. */
mutex_lock(&binderfs_minors_mutex);
- minor = ida_alloc_max(&binderfs_minors, BINDERFS_MAX_MINOR, GFP_KERNEL);
- mutex_unlock(&binderfs_minors_mutex);
- if (minor < 0)
+ if (++info->device_count <= info->mount_opts.max)
+ minor = ida_alloc_max(&binderfs_minors,
+ use_reserve ? BINDERFS_MAX_MINOR :
+ BINDERFS_MAX_MINOR_CAPPED,
+ GFP_KERNEL);
+ else
+ minor = -ENOSPC;
+ if (minor < 0) {
+ --info->device_count;
+ mutex_unlock(&binderfs_minors_mutex);
return minor;
+ }
+ mutex_unlock(&binderfs_minors_mutex);
ret = -ENOMEM;
device = kzalloc(sizeof(*device), GFP_KERNEL);
inode->i_uid = info->root_uid;
inode->i_gid = info->root_gid;
- name = kmalloc(name_len, GFP_KERNEL);
+ req->name[BINDERFS_MAX_NAME] = '\0'; /* NUL-terminate */
+ name_len = strlen(req->name);
+ /* Make sure to include terminating NUL byte */
+ name = kmemdup(req->name, name_len + 1, GFP_KERNEL);
if (!name)
goto err;
- strscpy(name, req->name, name_len);
-
device->binderfs_inode = inode;
device->context.binder_context_mgr_uid = INVALID_UID;
device->context.name = name;
root = sb->s_root;
inode_lock(d_inode(root));
- dentry = d_alloc_name(root, name);
- if (!dentry) {
+
+ /* look it up */
+ dentry = lookup_one_len(name, root, name_len);
+ if (IS_ERR(dentry)) {
inode_unlock(d_inode(root));
- ret = -ENOMEM;
+ ret = PTR_ERR(dentry);
goto err;
}
- /* Verify that the name userspace gave us is not already in use. */
- dup = d_lookup(root, &dentry->d_name);
- if (dup) {
- if (d_really_is_positive(dup)) {
- dput(dup);
- dput(dentry);
- inode_unlock(d_inode(root));
- ret = -EEXIST;
- goto err;
- }
- dput(dup);
+ if (d_really_is_positive(dentry)) {
+ /* already exists */
+ dput(dentry);
+ inode_unlock(d_inode(root));
+ ret = -EEXIST;
+ goto err;
}
inode->i_private = device;
- d_add(dentry, inode);
+ d_instantiate(dentry, inode);
fsnotify_create(root->d_inode, dentry);
inode_unlock(d_inode(root));
kfree(name);
kfree(device);
mutex_lock(&binderfs_minors_mutex);
+ --info->device_count;
ida_free(&binderfs_minors, minor);
mutex_unlock(&binderfs_minors_mutex);
iput(inode);
static void binderfs_evict_inode(struct inode *inode)
{
struct binder_device *device = inode->i_private;
+ struct binderfs_info *info = BINDERFS_I(inode);
clear_inode(inode);
return;
mutex_lock(&binderfs_minors_mutex);
+ --info->device_count;
ida_free(&binderfs_minors, device->miscdev.minor);
mutex_unlock(&binderfs_minors_mutex);
kfree(device);
}
+/**
+ * binderfs_parse_mount_opts - parse binderfs mount options
+ * @data: options to set (can be NULL in which case defaults are used)
+ */
+static int binderfs_parse_mount_opts(char *data,
+ struct binderfs_mount_opts *opts)
+{
+ char *p;
+ opts->max = BINDERFS_MAX_MINOR;
+
+ while ((p = strsep(&data, ",")) != NULL) {
+ substring_t args[MAX_OPT_ARGS];
+ int token;
+ int max_devices;
+
+ if (!*p)
+ continue;
+
+ token = match_token(p, tokens, args);
+ switch (token) {
+ case Opt_max:
+ if (match_int(&args[0], &max_devices) ||
+ (max_devices < 0 ||
+ (max_devices > BINDERFS_MAX_MINOR)))
+ return -EINVAL;
+
+ opts->max = max_devices;
+ break;
+ default:
+ pr_err("Invalid mount options\n");
+ return -EINVAL;
+ }
+ }
+
+ return 0;
+}
+
+static int binderfs_remount(struct super_block *sb, int *flags, char *data)
+{
+ struct binderfs_info *info = sb->s_fs_info;
+ return binderfs_parse_mount_opts(data, &info->mount_opts);
+}
+
+static int binderfs_show_mount_opts(struct seq_file *seq, struct dentry *root)
+{
+ struct binderfs_info *info;
+
+ info = root->d_sb->s_fs_info;
+ if (info->mount_opts.max <= BINDERFS_MAX_MINOR)
+ seq_printf(seq, ",max=%d", info->mount_opts.max);
+
+ return 0;
+}
+
static const struct super_operations binderfs_super_ops = {
- .statfs = simple_statfs,
- .evict_inode = binderfs_evict_inode,
+ .evict_inode = binderfs_evict_inode,
+ .remount_fs = binderfs_remount,
+ .show_options = binderfs_show_mount_opts,
+ .statfs = simple_statfs,
};
+static inline bool is_binderfs_control_device(const struct dentry *dentry)
+{
+ struct binderfs_info *info = dentry->d_sb->s_fs_info;
+ return info->control_dentry == dentry;
+}
+
static int binderfs_rename(struct inode *old_dir, struct dentry *old_dentry,
struct inode *new_dir, struct dentry *new_dentry,
unsigned int flags)
{
- struct inode *inode = d_inode(old_dentry);
-
- /* binderfs doesn't support directories. */
- if (d_is_dir(old_dentry))
+ if (is_binderfs_control_device(old_dentry) ||
+ is_binderfs_control_device(new_dentry))
return -EPERM;
- if (flags & ~RENAME_NOREPLACE)
- return -EINVAL;
-
- if (!simple_empty(new_dentry))
- return -ENOTEMPTY;
-
- if (d_really_is_positive(new_dentry))
- simple_unlink(new_dir, new_dentry);
-
- old_dir->i_ctime = old_dir->i_mtime = new_dir->i_ctime =
- new_dir->i_mtime = inode->i_ctime = current_time(old_dir);
-
- return 0;
+ return simple_rename(old_dir, old_dentry, new_dir, new_dentry, flags);
}
static int binderfs_unlink(struct inode *dir, struct dentry *dentry)
{
- /*
- * The control dentry is only ever touched during mount so checking it
- * here should not require us to take lock.
- */
- if (BINDERFS_I(dir)->control_dentry == dentry)
+ if (is_binderfs_control_device(dentry))
return -EPERM;
return simple_unlink(dir, dentry);
struct inode *inode = NULL;
struct dentry *root = sb->s_root;
struct binderfs_info *info = sb->s_fs_info;
+#if defined(CONFIG_IPC_NS)
+ bool use_reserve = (info->ipc_ns == &init_ipc_ns);
+#else
+ bool use_reserve = true;
+#endif
device = kzalloc(sizeof(*device), GFP_KERNEL);
if (!device)
return -ENOMEM;
- inode_lock(d_inode(root));
-
/* If we have already created a binder-control node, return. */
if (info->control_dentry) {
ret = 0;
/* Reserve a new minor number for the new device. */
mutex_lock(&binderfs_minors_mutex);
- minor = ida_alloc_max(&binderfs_minors, BINDERFS_MAX_MINOR, GFP_KERNEL);
+ minor = ida_alloc_max(&binderfs_minors,
+ use_reserve ? BINDERFS_MAX_MINOR :
+ BINDERFS_MAX_MINOR_CAPPED,
+ GFP_KERNEL);
mutex_unlock(&binderfs_minors_mutex);
if (minor < 0) {
ret = minor;
inode->i_private = device;
info->control_dentry = dentry;
d_add(dentry, inode);
- inode_unlock(d_inode(root));
return 0;
out:
- inode_unlock(d_inode(root));
kfree(device);
iput(inode);
static int binderfs_fill_super(struct super_block *sb, void *data, int silent)
{
+ int ret;
struct binderfs_info *info;
- int ret = -ENOMEM;
struct inode *inode = NULL;
- struct ipc_namespace *ipc_ns = sb->s_fs_info;
-
- get_ipc_ns(ipc_ns);
sb->s_blocksize = PAGE_SIZE;
sb->s_blocksize_bits = PAGE_SHIFT;
sb->s_op = &binderfs_super_ops;
sb->s_time_gran = 1;
- info = kzalloc(sizeof(struct binderfs_info), GFP_KERNEL);
- if (!info)
- goto err_without_dentry;
+ sb->s_fs_info = kzalloc(sizeof(struct binderfs_info), GFP_KERNEL);
+ if (!sb->s_fs_info)
+ return -ENOMEM;
+ info = sb->s_fs_info;
+
+ info->ipc_ns = get_ipc_ns(current->nsproxy->ipc_ns);
+
+ ret = binderfs_parse_mount_opts(data, &info->mount_opts);
+ if (ret)
+ return ret;
- info->ipc_ns = ipc_ns;
info->root_gid = make_kgid(sb->s_user_ns, 0);
if (!gid_valid(info->root_gid))
info->root_gid = GLOBAL_ROOT_GID;
if (!uid_valid(info->root_uid))
info->root_uid = GLOBAL_ROOT_UID;
- sb->s_fs_info = info;
-
inode = new_inode(sb);
if (!inode)
- goto err_without_dentry;
+ return -ENOMEM;
inode->i_ino = FIRST_INODE;
inode->i_fop = &simple_dir_operations;
sb->s_root = d_make_root(inode);
if (!sb->s_root)
- goto err_without_dentry;
-
- ret = binderfs_binder_ctl_create(sb);
- if (ret)
- goto err_with_dentry;
-
- return 0;
-
-err_with_dentry:
- dput(sb->s_root);
- sb->s_root = NULL;
-
-err_without_dentry:
- put_ipc_ns(ipc_ns);
- iput(inode);
- kfree(info);
-
- return ret;
-}
-
-static int binderfs_test_super(struct super_block *sb, void *data)
-{
- struct binderfs_info *info = sb->s_fs_info;
-
- if (info)
- return info->ipc_ns == data;
-
- return 0;
-}
+ return -ENOMEM;
-static int binderfs_set_super(struct super_block *sb, void *data)
-{
- sb->s_fs_info = data;
- return set_anon_super(sb, NULL);
+ return binderfs_binder_ctl_create(sb);
}
static struct dentry *binderfs_mount(struct file_system_type *fs_type,
int flags, const char *dev_name,
void *data)
{
- struct super_block *sb;
- struct ipc_namespace *ipc_ns = current->nsproxy->ipc_ns;
-
- if (!ns_capable(ipc_ns->user_ns, CAP_SYS_ADMIN))
- return ERR_PTR(-EPERM);
-
- sb = sget_userns(fs_type, binderfs_test_super, binderfs_set_super,
- flags, ipc_ns->user_ns, ipc_ns);
- if (IS_ERR(sb))
- return ERR_CAST(sb);
-
- if (!sb->s_root) {
- int ret = binderfs_fill_super(sb, data, flags & SB_SILENT ? 1 : 0);
- if (ret) {
- deactivate_locked_super(sb);
- return ERR_PTR(ret);
- }
-
- sb->s_flags |= SB_ACTIVE;
- }
-
- return dget(sb->s_root);
+ return mount_nodev(fs_type, flags, data, binderfs_fill_super);
}
static void binderfs_kill_super(struct super_block *sb)
{
struct binderfs_info *info = sb->s_fs_info;
+ kill_litter_super(sb);
+
if (info && info->ipc_ns)
put_ipc_ns(info->ipc_ns);
kfree(info);
- kill_litter_super(sb);
}
static struct file_system_type binder_fs_type = {
.fs_flags = FS_USERNS_MOUNT,
};
-static int __init init_binderfs(void)
+int __init init_binderfs(void)
{
int ret;
return ret;
}
- binderfs_mnt = kern_mount(&binder_fs_type);
- if (IS_ERR(binderfs_mnt)) {
- ret = PTR_ERR(binderfs_mnt);
- binderfs_mnt = NULL;
- unregister_filesystem(&binder_fs_type);
- unregister_chrdev_region(binderfs_dev, BINDERFS_MAX_MINOR);
- }
-
return ret;
}
-
-device_initcall(init_binderfs);
projects / linux-2.6-microblaze.git / blobdiff