diff options
Diffstat (limited to 'fs/notify/inotify')
| -rw-r--r-- | fs/notify/inotify/Kconfig | 17 | ||||
| -rw-r--r-- | fs/notify/inotify/Makefile | 2 | ||||
| -rw-r--r-- | fs/notify/inotify/inotify.h | 69 | ||||
| -rw-r--r-- | fs/notify/inotify/inotify_fsnotify.c | 209 | ||||
| -rw-r--r-- | fs/notify/inotify/inotify_user.c | 875 |
5 files changed, 1172 insertions, 0 deletions
diff --git a/fs/notify/inotify/Kconfig b/fs/notify/inotify/Kconfig new file mode 100644 index 0000000000..1cc8be25df --- /dev/null +++ b/fs/notify/inotify/Kconfig @@ -0,0 +1,17 @@ +# SPDX-License-Identifier: GPL-2.0-only +config INOTIFY_USER + bool "Inotify support for userspace" + select FSNOTIFY + default y + help + Say Y here to enable inotify support for userspace, including the + associated system calls. Inotify allows monitoring of both files and + directories via a single open fd. Events are read from the file + descriptor, which is also select()- and poll()-able. + Inotify fixes numerous shortcomings in dnotify and introduces several + new features including multiple file events, one-shot support, and + unmount notification. + + For more information, see <file:Documentation/filesystems/inotify.rst> + + If unsure, say Y. diff --git a/fs/notify/inotify/Makefile b/fs/notify/inotify/Makefile new file mode 100644 index 0000000000..812237eecf --- /dev/null +++ b/fs/notify/inotify/Makefile @@ -0,0 +1,2 @@ +# SPDX-License-Identifier: GPL-2.0-only +obj-$(CONFIG_INOTIFY_USER) += inotify_fsnotify.o inotify_user.o diff --git a/fs/notify/inotify/inotify.h b/fs/notify/inotify/inotify.h new file mode 100644 index 0000000000..7d5df7a215 --- /dev/null +++ b/fs/notify/inotify/inotify.h @@ -0,0 +1,69 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#include <linux/fsnotify_backend.h> +#include <linux/inotify.h> +#include <linux/slab.h> /* struct kmem_cache */ + +struct inotify_event_info { + struct fsnotify_event fse; + u32 mask; + int wd; + u32 sync_cookie; + int name_len; + char name[]; +}; + +struct inotify_inode_mark { + struct fsnotify_mark fsn_mark; + int wd; +}; + +static inline struct inotify_event_info *INOTIFY_E(struct fsnotify_event *fse) +{ + return container_of(fse, struct inotify_event_info, fse); +} + +/* + * INOTIFY_USER_FLAGS represents all of the mask bits that we expose to + * userspace. There is at least one bit (FS_EVENT_ON_CHILD) which is + * used only internally to the kernel. + */ +#define INOTIFY_USER_MASK (IN_ALL_EVENTS) + +static inline __u32 inotify_mark_user_mask(struct fsnotify_mark *fsn_mark) +{ + __u32 mask = fsn_mark->mask & INOTIFY_USER_MASK; + + if (fsn_mark->flags & FSNOTIFY_MARK_FLAG_EXCL_UNLINK) + mask |= IN_EXCL_UNLINK; + if (fsn_mark->flags & FSNOTIFY_MARK_FLAG_IN_ONESHOT) + mask |= IN_ONESHOT; + + return mask; +} + +extern void inotify_ignored_and_remove_idr(struct fsnotify_mark *fsn_mark, + struct fsnotify_group *group); +extern int inotify_handle_inode_event(struct fsnotify_mark *inode_mark, + u32 mask, struct inode *inode, + struct inode *dir, + const struct qstr *name, u32 cookie); + +extern const struct fsnotify_ops inotify_fsnotify_ops; +extern struct kmem_cache *inotify_inode_mark_cachep; + +#ifdef CONFIG_INOTIFY_USER +static inline void dec_inotify_instances(struct ucounts *ucounts) +{ + dec_ucount(ucounts, UCOUNT_INOTIFY_INSTANCES); +} + +static inline struct ucounts *inc_inotify_watches(struct ucounts *ucounts) +{ + return inc_ucount(ucounts->ns, ucounts->uid, UCOUNT_INOTIFY_WATCHES); +} + +static inline void dec_inotify_watches(struct ucounts *ucounts) +{ + dec_ucount(ucounts, UCOUNT_INOTIFY_WATCHES); +} +#endif diff --git a/fs/notify/inotify/inotify_fsnotify.c b/fs/notify/inotify/inotify_fsnotify.c new file mode 100644 index 0000000000..993375f0db --- /dev/null +++ b/fs/notify/inotify/inotify_fsnotify.c @@ -0,0 +1,209 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * fs/inotify_user.c - inotify support for userspace + * + * Authors: + * John McCutchan <ttb@tentacle.dhs.org> + * Robert Love <rml@novell.com> + * + * Copyright (C) 2005 John McCutchan + * Copyright 2006 Hewlett-Packard Development Company, L.P. + * + * Copyright (C) 2009 Eric Paris <Red Hat Inc> + * inotify was largely rewriten to make use of the fsnotify infrastructure + */ + +#include <linux/dcache.h> /* d_unlinked */ +#include <linux/fs.h> /* struct inode */ +#include <linux/fsnotify_backend.h> +#include <linux/inotify.h> +#include <linux/path.h> /* struct path */ +#include <linux/slab.h> /* kmem_* */ +#include <linux/types.h> +#include <linux/sched.h> +#include <linux/sched/user.h> +#include <linux/sched/mm.h> + +#include "inotify.h" + +/* + * Check if 2 events contain the same information. + */ +static bool event_compare(struct fsnotify_event *old_fsn, + struct fsnotify_event *new_fsn) +{ + struct inotify_event_info *old, *new; + + old = INOTIFY_E(old_fsn); + new = INOTIFY_E(new_fsn); + if (old->mask & FS_IN_IGNORED) + return false; + if ((old->mask == new->mask) && + (old->wd == new->wd) && + (old->name_len == new->name_len) && + (!old->name_len || !strcmp(old->name, new->name))) + return true; + return false; +} + +static int inotify_merge(struct fsnotify_group *group, + struct fsnotify_event *event) +{ + struct list_head *list = &group->notification_list; + struct fsnotify_event *last_event; + + last_event = list_entry(list->prev, struct fsnotify_event, list); + return event_compare(last_event, event); +} + +int inotify_handle_inode_event(struct fsnotify_mark *inode_mark, u32 mask, + struct inode *inode, struct inode *dir, + const struct qstr *name, u32 cookie) +{ + struct inotify_inode_mark *i_mark; + struct inotify_event_info *event; + struct fsnotify_event *fsn_event; + struct fsnotify_group *group = inode_mark->group; + int ret; + int len = 0, wd; + int alloc_len = sizeof(struct inotify_event_info); + struct mem_cgroup *old_memcg; + + if (name) { + len = name->len; + alloc_len += len + 1; + } + + pr_debug("%s: group=%p mark=%p mask=%x\n", __func__, group, inode_mark, + mask); + + i_mark = container_of(inode_mark, struct inotify_inode_mark, + fsn_mark); + + /* + * We can be racing with mark being detached. Don't report event with + * invalid wd. + */ + wd = READ_ONCE(i_mark->wd); + if (wd == -1) + return 0; + /* + * Whoever is interested in the event, pays for the allocation. Do not + * trigger OOM killer in the target monitoring memcg as it may have + * security repercussion. + */ + old_memcg = set_active_memcg(group->memcg); + event = kmalloc(alloc_len, GFP_KERNEL_ACCOUNT | __GFP_RETRY_MAYFAIL); + set_active_memcg(old_memcg); + + if (unlikely(!event)) { + /* + * Treat lost event due to ENOMEM the same way as queue + * overflow to let userspace know event was lost. + */ + fsnotify_queue_overflow(group); + return -ENOMEM; + } + + /* + * We now report FS_ISDIR flag with MOVE_SELF and DELETE_SELF events + * for fanotify. inotify never reported IN_ISDIR with those events. + * It looks like an oversight, but to avoid the risk of breaking + * existing inotify programs, mask the flag out from those events. + */ + if (mask & (IN_MOVE_SELF | IN_DELETE_SELF)) + mask &= ~IN_ISDIR; + + fsn_event = &event->fse; + fsnotify_init_event(fsn_event); + event->mask = mask; + event->wd = wd; + event->sync_cookie = cookie; + event->name_len = len; + if (len) + strcpy(event->name, name->name); + + ret = fsnotify_add_event(group, fsn_event, inotify_merge); + if (ret) { + /* Our event wasn't used in the end. Free it. */ + fsnotify_destroy_event(group, fsn_event); + } + + if (inode_mark->flags & FSNOTIFY_MARK_FLAG_IN_ONESHOT) + fsnotify_destroy_mark(inode_mark, group); + + return 0; +} + +static void inotify_freeing_mark(struct fsnotify_mark *fsn_mark, struct fsnotify_group *group) +{ + inotify_ignored_and_remove_idr(fsn_mark, group); +} + +/* + * This is NEVER supposed to be called. Inotify marks should either have been + * removed from the idr when the watch was removed or in the + * fsnotify_destroy_mark_by_group() call when the inotify instance was being + * torn down. This is only called if the idr is about to be freed but there + * are still marks in it. + */ +static int idr_callback(int id, void *p, void *data) +{ + struct fsnotify_mark *fsn_mark; + struct inotify_inode_mark *i_mark; + static bool warned = false; + + if (warned) + return 0; + + warned = true; + fsn_mark = p; + i_mark = container_of(fsn_mark, struct inotify_inode_mark, fsn_mark); + + WARN(1, "inotify closing but id=%d for fsn_mark=%p in group=%p still in " + "idr. Probably leaking memory\n", id, p, data); + + /* + * I'm taking the liberty of assuming that the mark in question is a + * valid address and I'm dereferencing it. This might help to figure + * out why we got here and the panic is no worse than the original + * BUG() that was here. + */ + if (fsn_mark) + printk(KERN_WARNING "fsn_mark->group=%p wd=%d\n", + fsn_mark->group, i_mark->wd); + return 0; +} + +static void inotify_free_group_priv(struct fsnotify_group *group) +{ + /* ideally the idr is empty and we won't hit the BUG in the callback */ + idr_for_each(&group->inotify_data.idr, idr_callback, group); + idr_destroy(&group->inotify_data.idr); + if (group->inotify_data.ucounts) + dec_inotify_instances(group->inotify_data.ucounts); +} + +static void inotify_free_event(struct fsnotify_group *group, + struct fsnotify_event *fsn_event) +{ + kfree(INOTIFY_E(fsn_event)); +} + +/* ding dong the mark is dead */ +static void inotify_free_mark(struct fsnotify_mark *fsn_mark) +{ + struct inotify_inode_mark *i_mark; + + i_mark = container_of(fsn_mark, struct inotify_inode_mark, fsn_mark); + + kmem_cache_free(inotify_inode_mark_cachep, i_mark); +} + +const struct fsnotify_ops inotify_fsnotify_ops = { + .handle_inode_event = inotify_handle_inode_event, + .free_group_priv = inotify_free_group_priv, + .free_event = inotify_free_event, + .freeing_mark = inotify_freeing_mark, + .free_mark = inotify_free_mark, +}; diff --git a/fs/notify/inotify/inotify_user.c b/fs/notify/inotify/inotify_user.c new file mode 100644 index 0000000000..1c4bfdab00 --- /dev/null +++ b/fs/notify/inotify/inotify_user.c @@ -0,0 +1,875 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * fs/inotify_user.c - inotify support for userspace + * + * Authors: + * John McCutchan <ttb@tentacle.dhs.org> + * Robert Love <rml@novell.com> + * + * Copyright (C) 2005 John McCutchan + * Copyright 2006 Hewlett-Packard Development Company, L.P. + * + * Copyright (C) 2009 Eric Paris <Red Hat Inc> + * inotify was largely rewriten to make use of the fsnotify infrastructure + */ + +#include <linux/file.h> +#include <linux/fs.h> /* struct inode */ +#include <linux/fsnotify_backend.h> +#include <linux/idr.h> +#include <linux/init.h> /* fs_initcall */ +#include <linux/inotify.h> +#include <linux/kernel.h> /* roundup() */ +#include <linux/namei.h> /* LOOKUP_FOLLOW */ +#include <linux/sched/signal.h> +#include <linux/slab.h> /* struct kmem_cache */ +#include <linux/syscalls.h> +#include <linux/types.h> +#include <linux/anon_inodes.h> +#include <linux/uaccess.h> +#include <linux/poll.h> +#include <linux/wait.h> +#include <linux/memcontrol.h> +#include <linux/security.h> + +#include "inotify.h" +#include "../fdinfo.h" + +#include <asm/ioctls.h> + +/* + * An inotify watch requires allocating an inotify_inode_mark structure as + * well as pinning the watched inode. Doubling the size of a VFS inode + * should be more than enough to cover the additional filesystem inode + * size increase. + */ +#define INOTIFY_WATCH_COST (sizeof(struct inotify_inode_mark) + \ + 2 * sizeof(struct inode)) + +/* configurable via /proc/sys/fs/inotify/ */ +static int inotify_max_queued_events __read_mostly; + +struct kmem_cache *inotify_inode_mark_cachep __read_mostly; + +#ifdef CONFIG_SYSCTL + +#include <linux/sysctl.h> + +static long it_zero = 0; +static long it_int_max = INT_MAX; + +static struct ctl_table inotify_table[] = { + { + .procname = "max_user_instances", + .data = &init_user_ns.ucount_max[UCOUNT_INOTIFY_INSTANCES], + .maxlen = sizeof(long), + .mode = 0644, + .proc_handler = proc_doulongvec_minmax, + .extra1 = &it_zero, + .extra2 = &it_int_max, + }, + { + .procname = "max_user_watches", + .data = &init_user_ns.ucount_max[UCOUNT_INOTIFY_WATCHES], + .maxlen = sizeof(long), + .mode = 0644, + .proc_handler = proc_doulongvec_minmax, + .extra1 = &it_zero, + .extra2 = &it_int_max, + }, + { + .procname = "max_queued_events", + .data = &inotify_max_queued_events, + .maxlen = sizeof(int), + .mode = 0644, + .proc_handler = proc_dointvec_minmax, + .extra1 = SYSCTL_ZERO + }, + { } +}; + +static void __init inotify_sysctls_init(void) +{ + register_sysctl("fs/inotify", inotify_table); +} + +#else +#define inotify_sysctls_init() do { } while (0) +#endif /* CONFIG_SYSCTL */ + +static inline __u32 inotify_arg_to_mask(struct inode *inode, u32 arg) +{ + __u32 mask; + + /* + * Everything should receive events when the inode is unmounted. + * All directories care about children. + */ + mask = (FS_UNMOUNT); + if (S_ISDIR(inode->i_mode)) + mask |= FS_EVENT_ON_CHILD; + + /* mask off the flags used to open the fd */ + mask |= (arg & INOTIFY_USER_MASK); + + return mask; +} + +#define INOTIFY_MARK_FLAGS \ + (FSNOTIFY_MARK_FLAG_EXCL_UNLINK | FSNOTIFY_MARK_FLAG_IN_ONESHOT) + +static inline unsigned int inotify_arg_to_flags(u32 arg) +{ + unsigned int flags = 0; + + if (arg & IN_EXCL_UNLINK) + flags |= FSNOTIFY_MARK_FLAG_EXCL_UNLINK; + if (arg & IN_ONESHOT) + flags |= FSNOTIFY_MARK_FLAG_IN_ONESHOT; + + return flags; +} + +static inline u32 inotify_mask_to_arg(__u32 mask) +{ + return mask & (IN_ALL_EVENTS | IN_ISDIR | IN_UNMOUNT | IN_IGNORED | + IN_Q_OVERFLOW); +} + +/* inotify userspace file descriptor functions */ +static __poll_t inotify_poll(struct file *file, poll_table *wait) +{ + struct fsnotify_group *group = file->private_data; + __poll_t ret = 0; + + poll_wait(file, &group->notification_waitq, wait); + spin_lock(&group->notification_lock); + if (!fsnotify_notify_queue_is_empty(group)) + ret = EPOLLIN | EPOLLRDNORM; + spin_unlock(&group->notification_lock); + + return ret; +} + +static int round_event_name_len(struct fsnotify_event *fsn_event) +{ + struct inotify_event_info *event; + + event = INOTIFY_E(fsn_event); + if (!event->name_len) + return 0; + return roundup(event->name_len + 1, sizeof(struct inotify_event)); +} + +/* + * Get an inotify_kernel_event if one exists and is small + * enough to fit in "count". Return an error pointer if + * not large enough. + * + * Called with the group->notification_lock held. + */ +static struct fsnotify_event *get_one_event(struct fsnotify_group *group, + size_t count) +{ + size_t event_size = sizeof(struct inotify_event); + struct fsnotify_event *event; + + event = fsnotify_peek_first_event(group); + if (!event) + return NULL; + + pr_debug("%s: group=%p event=%p\n", __func__, group, event); + + event_size += round_event_name_len(event); + if (event_size > count) + return ERR_PTR(-EINVAL); + + /* held the notification_lock the whole time, so this is the + * same event we peeked above */ + fsnotify_remove_first_event(group); + + return event; +} + +/* + * Copy an event to user space, returning how much we copied. + * + * We already checked that the event size is smaller than the + * buffer we had in "get_one_event()" above. + */ +static ssize_t copy_event_to_user(struct fsnotify_group *group, + struct fsnotify_event *fsn_event, + char __user *buf) +{ + struct inotify_event inotify_event; + struct inotify_event_info *event; + size_t event_size = sizeof(struct inotify_event); + size_t name_len; + size_t pad_name_len; + + pr_debug("%s: group=%p event=%p\n", __func__, group, fsn_event); + + event = INOTIFY_E(fsn_event); + name_len = event->name_len; + /* + * round up name length so it is a multiple of event_size + * plus an extra byte for the terminating '\0'. + */ + pad_name_len = round_event_name_len(fsn_event); + inotify_event.len = pad_name_len; + inotify_event.mask = inotify_mask_to_arg(event->mask); + inotify_event.wd = event->wd; + inotify_event.cookie = event->sync_cookie; + + /* send the main event */ + if (copy_to_user(buf, &inotify_event, event_size)) + return -EFAULT; + + buf += event_size; + + /* + * fsnotify only stores the pathname, so here we have to send the pathname + * and then pad that pathname out to a multiple of sizeof(inotify_event) + * with zeros. + */ + if (pad_name_len) { + /* copy the path name */ + if (copy_to_user(buf, event->name, name_len)) + return -EFAULT; + buf += name_len; + + /* fill userspace with 0's */ + if (clear_user(buf, pad_name_len - name_len)) + return -EFAULT; + event_size += pad_name_len; + } + + return event_size; +} + +static ssize_t inotify_read(struct file *file, char __user *buf, + size_t count, loff_t *pos) +{ + struct fsnotify_group *group; + struct fsnotify_event *kevent; + char __user *start; + int ret; + DEFINE_WAIT_FUNC(wait, woken_wake_function); + + start = buf; + group = file->private_data; + + add_wait_queue(&group->notification_waitq, &wait); + while (1) { + spin_lock(&group->notification_lock); + kevent = get_one_event(group, count); + spin_unlock(&group->notification_lock); + + pr_debug("%s: group=%p kevent=%p\n", __func__, group, kevent); + + if (kevent) { + ret = PTR_ERR(kevent); + if (IS_ERR(kevent)) + break; + ret = copy_event_to_user(group, kevent, buf); + fsnotify_destroy_event(group, kevent); + if (ret < 0) + break; + buf += ret; + count -= ret; + continue; + } + + ret = -EAGAIN; + if (file->f_flags & O_NONBLOCK) + break; + ret = -ERESTARTSYS; + if (signal_pending(current)) + break; + + if (start != buf) + break; + + wait_woken(&wait, TASK_INTERRUPTIBLE, MAX_SCHEDULE_TIMEOUT); + } + remove_wait_queue(&group->notification_waitq, &wait); + + if (start != buf && ret != -EFAULT) + ret = buf - start; + return ret; +} + +static int inotify_release(struct inode *ignored, struct file *file) +{ + struct fsnotify_group *group = file->private_data; + + pr_debug("%s: group=%p\n", __func__, group); + + /* free this group, matching get was inotify_init->fsnotify_obtain_group */ + fsnotify_destroy_group(group); + + return 0; +} + +static long inotify_ioctl(struct file *file, unsigned int cmd, + unsigned long arg) +{ + struct fsnotify_group *group; + struct fsnotify_event *fsn_event; + void __user *p; + int ret = -ENOTTY; + size_t send_len = 0; + + group = file->private_data; + p = (void __user *) arg; + + pr_debug("%s: group=%p cmd=%u\n", __func__, group, cmd); + + switch (cmd) { + case FIONREAD: + spin_lock(&group->notification_lock); + list_for_each_entry(fsn_event, &group->notification_list, + list) { + send_len += sizeof(struct inotify_event); + send_len += round_event_name_len(fsn_event); + } + spin_unlock(&group->notification_lock); + ret = put_user(send_len, (int __user *) p); + break; +#ifdef CONFIG_CHECKPOINT_RESTORE + case INOTIFY_IOC_SETNEXTWD: + ret = -EINVAL; + if (arg >= 1 && arg <= INT_MAX) { + struct inotify_group_private_data *data; + + data = &group->inotify_data; + spin_lock(&data->idr_lock); + idr_set_cursor(&data->idr, (unsigned int)arg); + spin_unlock(&data->idr_lock); + ret = 0; + } + break; +#endif /* CONFIG_CHECKPOINT_RESTORE */ + } + + return ret; +} + +static const struct file_operations inotify_fops = { + .show_fdinfo = inotify_show_fdinfo, + .poll = inotify_poll, + .read = inotify_read, + .fasync = fsnotify_fasync, + .release = inotify_release, + .unlocked_ioctl = inotify_ioctl, + .compat_ioctl = inotify_ioctl, + .llseek = noop_llseek, +}; + + +/* + * find_inode - resolve a user-given path to a specific inode + */ +static int inotify_find_inode(const char __user *dirname, struct path *path, + unsigned int flags, __u64 mask) +{ + int error; + + error = user_path_at(AT_FDCWD, dirname, flags, path); + if (error) + return error; + /* you can only watch an inode if you have read permissions on it */ + error = path_permission(path, MAY_READ); + if (error) { + path_put(path); + return error; + } + error = security_path_notify(path, mask, + FSNOTIFY_OBJ_TYPE_INODE); + if (error) + path_put(path); + + return error; +} + +static int inotify_add_to_idr(struct idr *idr, spinlock_t *idr_lock, + struct inotify_inode_mark *i_mark) +{ + int ret; + + idr_preload(GFP_KERNEL); + spin_lock(idr_lock); + + ret = idr_alloc_cyclic(idr, i_mark, 1, 0, GFP_NOWAIT); + if (ret >= 0) { + /* we added the mark to the idr, take a reference */ + i_mark->wd = ret; + fsnotify_get_mark(&i_mark->fsn_mark); + } + + spin_unlock(idr_lock); + idr_preload_end(); + return ret < 0 ? ret : 0; +} + +static struct inotify_inode_mark *inotify_idr_find_locked(struct fsnotify_group *group, + int wd) +{ + struct idr *idr = &group->inotify_data.idr; + spinlock_t *idr_lock = &group->inotify_data.idr_lock; + struct inotify_inode_mark *i_mark; + + assert_spin_locked(idr_lock); + + i_mark = idr_find(idr, wd); + if (i_mark) { + struct fsnotify_mark *fsn_mark = &i_mark->fsn_mark; + + fsnotify_get_mark(fsn_mark); + /* One ref for being in the idr, one ref we just took */ + BUG_ON(refcount_read(&fsn_mark->refcnt) < 2); + } + + return i_mark; +} + +static struct inotify_inode_mark *inotify_idr_find(struct fsnotify_group *group, + int wd) +{ + struct inotify_inode_mark *i_mark; + spinlock_t *idr_lock = &group->inotify_data.idr_lock; + + spin_lock(idr_lock); + i_mark = inotify_idr_find_locked(group, wd); + spin_unlock(idr_lock); + + return i_mark; +} + +/* + * Remove the mark from the idr (if present) and drop the reference + * on the mark because it was in the idr. + */ +static void inotify_remove_from_idr(struct fsnotify_group *group, + struct inotify_inode_mark *i_mark) +{ + struct idr *idr = &group->inotify_data.idr; + spinlock_t *idr_lock = &group->inotify_data.idr_lock; + struct inotify_inode_mark *found_i_mark = NULL; + int wd; + + spin_lock(idr_lock); + wd = i_mark->wd; + + /* + * does this i_mark think it is in the idr? we shouldn't get called + * if it wasn't.... + */ + if (wd == -1) { + WARN_ONCE(1, "%s: i_mark=%p i_mark->wd=%d i_mark->group=%p\n", + __func__, i_mark, i_mark->wd, i_mark->fsn_mark.group); + goto out; + } + + /* Lets look in the idr to see if we find it */ + found_i_mark = inotify_idr_find_locked(group, wd); + if (unlikely(!found_i_mark)) { + WARN_ONCE(1, "%s: i_mark=%p i_mark->wd=%d i_mark->group=%p\n", + __func__, i_mark, i_mark->wd, i_mark->fsn_mark.group); + goto out; + } + + /* + * We found an mark in the idr at the right wd, but it's + * not the mark we were told to remove. eparis seriously + * fucked up somewhere. + */ + if (unlikely(found_i_mark != i_mark)) { + WARN_ONCE(1, "%s: i_mark=%p i_mark->wd=%d i_mark->group=%p " + "found_i_mark=%p found_i_mark->wd=%d " + "found_i_mark->group=%p\n", __func__, i_mark, + i_mark->wd, i_mark->fsn_mark.group, found_i_mark, + found_i_mark->wd, found_i_mark->fsn_mark.group); + goto out; + } + + /* + * One ref for being in the idr + * one ref grabbed by inotify_idr_find + */ + if (unlikely(refcount_read(&i_mark->fsn_mark.refcnt) < 2)) { + printk(KERN_ERR "%s: i_mark=%p i_mark->wd=%d i_mark->group=%p\n", + __func__, i_mark, i_mark->wd, i_mark->fsn_mark.group); + /* we can't really recover with bad ref cnting.. */ + BUG(); + } + + idr_remove(idr, wd); + /* Removed from the idr, drop that ref. */ + fsnotify_put_mark(&i_mark->fsn_mark); +out: + i_mark->wd = -1; + spin_unlock(idr_lock); + /* match the ref taken by inotify_idr_find_locked() */ + if (found_i_mark) + fsnotify_put_mark(&found_i_mark->fsn_mark); +} + +/* + * Send IN_IGNORED for this wd, remove this wd from the idr. + */ +void inotify_ignored_and_remove_idr(struct fsnotify_mark *fsn_mark, + struct fsnotify_group *group) +{ + struct inotify_inode_mark *i_mark; + + /* Queue ignore event for the watch */ + inotify_handle_inode_event(fsn_mark, FS_IN_IGNORED, NULL, NULL, NULL, + 0); + + i_mark = container_of(fsn_mark, struct inotify_inode_mark, fsn_mark); + /* remove this mark from the idr */ + inotify_remove_from_idr(group, i_mark); + + dec_inotify_watches(group->inotify_data.ucounts); +} + +static int inotify_update_existing_watch(struct fsnotify_group *group, + struct inode *inode, + u32 arg) +{ + struct fsnotify_mark *fsn_mark; + struct inotify_inode_mark *i_mark; + __u32 old_mask, new_mask; + int replace = !(arg & IN_MASK_ADD); + int create = (arg & IN_MASK_CREATE); + int ret; + + fsn_mark = fsnotify_find_mark(&inode->i_fsnotify_marks, group); + if (!fsn_mark) + return -ENOENT; + else if (create) { + ret = -EEXIST; + goto out; + } + + i_mark = container_of(fsn_mark, struct inotify_inode_mark, fsn_mark); + + spin_lock(&fsn_mark->lock); + old_mask = fsn_mark->mask; + if (replace) { + fsn_mark->mask = 0; + fsn_mark->flags &= ~INOTIFY_MARK_FLAGS; + } + fsn_mark->mask |= inotify_arg_to_mask(inode, arg); + fsn_mark->flags |= inotify_arg_to_flags(arg); + new_mask = fsn_mark->mask; + spin_unlock(&fsn_mark->lock); + + if (old_mask != new_mask) { + /* more bits in old than in new? */ + int dropped = (old_mask & ~new_mask); + /* more bits in this fsn_mark than the inode's mask? */ + int do_inode = (new_mask & ~inode->i_fsnotify_mask); + + /* update the inode with this new fsn_mark */ + if (dropped || do_inode) + fsnotify_recalc_mask(inode->i_fsnotify_marks); + + } + + /* return the wd */ + ret = i_mark->wd; + +out: + /* match the get from fsnotify_find_mark() */ + fsnotify_put_mark(fsn_mark); + + return ret; +} + +static int inotify_new_watch(struct fsnotify_group *group, + struct inode *inode, + u32 arg) +{ + struct inotify_inode_mark *tmp_i_mark; + int ret; + struct idr *idr = &group->inotify_data.idr; + spinlock_t *idr_lock = &group->inotify_data.idr_lock; + + tmp_i_mark = kmem_cache_alloc(inotify_inode_mark_cachep, GFP_KERNEL); + if (unlikely(!tmp_i_mark)) + return -ENOMEM; + + fsnotify_init_mark(&tmp_i_mark->fsn_mark, group); + tmp_i_mark->fsn_mark.mask = inotify_arg_to_mask(inode, arg); + tmp_i_mark->fsn_mark.flags = inotify_arg_to_flags(arg); + tmp_i_mark->wd = -1; + + ret = inotify_add_to_idr(idr, idr_lock, tmp_i_mark); + if (ret) + goto out_err; + + /* increment the number of watches the user has */ + if (!inc_inotify_watches(group->inotify_data.ucounts)) { + inotify_remove_from_idr(group, tmp_i_mark); + ret = -ENOSPC; + goto out_err; + } + + /* we are on the idr, now get on the inode */ + ret = fsnotify_add_inode_mark_locked(&tmp_i_mark->fsn_mark, inode, 0); + if (ret) { + /* we failed to get on the inode, get off the idr */ + inotify_remove_from_idr(group, tmp_i_mark); + goto out_err; + } + + + /* return the watch descriptor for this new mark */ + ret = tmp_i_mark->wd; + +out_err: + /* match the ref from fsnotify_init_mark() */ + fsnotify_put_mark(&tmp_i_mark->fsn_mark); + + return ret; +} + +static int inotify_update_watch(struct fsnotify_group *group, struct inode *inode, u32 arg) +{ + int ret = 0; + + fsnotify_group_lock(group); + /* try to update and existing watch with the new arg */ + ret = inotify_update_existing_watch(group, inode, arg); + /* no mark present, try to add a new one */ + if (ret == -ENOENT) + ret = inotify_new_watch(group, inode, arg); + fsnotify_group_unlock(group); + + return ret; +} + +static struct fsnotify_group *inotify_new_group(unsigned int max_events) +{ + struct fsnotify_group *group; + struct inotify_event_info *oevent; + + group = fsnotify_alloc_group(&inotify_fsnotify_ops, + FSNOTIFY_GROUP_USER); + if (IS_ERR(group)) + return group; + + oevent = kmalloc(sizeof(struct inotify_event_info), GFP_KERNEL_ACCOUNT); + if (unlikely(!oevent)) { + fsnotify_destroy_group(group); + return ERR_PTR(-ENOMEM); + } + group->overflow_event = &oevent->fse; + fsnotify_init_event(group->overflow_event); + oevent->mask = FS_Q_OVERFLOW; + oevent->wd = -1; + oevent->sync_cookie = 0; + oevent->name_len = 0; + + group->max_events = max_events; + group->memcg = get_mem_cgroup_from_mm(current->mm); + + spin_lock_init(&group->inotify_data.idr_lock); + idr_init(&group->inotify_data.idr); + group->inotify_data.ucounts = inc_ucount(current_user_ns(), + current_euid(), + UCOUNT_INOTIFY_INSTANCES); + + if (!group->inotify_data.ucounts) { + fsnotify_destroy_group(group); + return ERR_PTR(-EMFILE); + } + + return group; +} + + +/* inotify syscalls */ +static int do_inotify_init(int flags) +{ + struct fsnotify_group *group; + int ret; + + /* Check the IN_* constants for consistency. */ + BUILD_BUG_ON(IN_CLOEXEC != O_CLOEXEC); + BUILD_BUG_ON(IN_NONBLOCK != O_NONBLOCK); + + if (flags & ~(IN_CLOEXEC | IN_NONBLOCK)) + return -EINVAL; + + /* fsnotify_obtain_group took a reference to group, we put this when we kill the file in the end */ + group = inotify_new_group(inotify_max_queued_events); + if (IS_ERR(group)) + return PTR_ERR(group); + + ret = anon_inode_getfd("inotify", &inotify_fops, group, + O_RDONLY | flags); + if (ret < 0) + fsnotify_destroy_group(group); + + return ret; +} + +SYSCALL_DEFINE1(inotify_init1, int, flags) +{ + return do_inotify_init(flags); +} + +SYSCALL_DEFINE0(inotify_init) +{ + return do_inotify_init(0); +} + +SYSCALL_DEFINE3(inotify_add_watch, int, fd, const char __user *, pathname, + u32, mask) +{ + struct fsnotify_group *group; + struct inode *inode; + struct path path; + struct fd f; + int ret; + unsigned flags = 0; + + /* + * We share a lot of code with fs/dnotify. We also share + * the bit layout between inotify's IN_* and the fsnotify + * FS_*. This check ensures that only the inotify IN_* + * bits get passed in and set in watches/events. + */ + if (unlikely(mask & ~ALL_INOTIFY_BITS)) + return -EINVAL; + /* + * Require at least one valid bit set in the mask. + * Without _something_ set, we would have no events to + * watch for. + */ + if (unlikely(!(mask & ALL_INOTIFY_BITS))) + return -EINVAL; + + f = fdget(fd); + if (unlikely(!f.file)) + return -EBADF; + + /* IN_MASK_ADD and IN_MASK_CREATE don't make sense together */ + if (unlikely((mask & IN_MASK_ADD) && (mask & IN_MASK_CREATE))) { + ret = -EINVAL; + goto fput_and_out; + } + + /* verify that this is indeed an inotify instance */ + if (unlikely(f.file->f_op != &inotify_fops)) { + ret = -EINVAL; + goto fput_and_out; + } + + if (!(mask & IN_DONT_FOLLOW)) + flags |= LOOKUP_FOLLOW; + if (mask & IN_ONLYDIR) + flags |= LOOKUP_DIRECTORY; + + ret = inotify_find_inode(pathname, &path, flags, + (mask & IN_ALL_EVENTS)); + if (ret) + goto fput_and_out; + + /* inode held in place by reference to path; group by fget on fd */ + inode = path.dentry->d_inode; + group = f.file->private_data; + + /* create/update an inode mark */ + ret = inotify_update_watch(group, inode, mask); + path_put(&path); +fput_and_out: + fdput(f); + return ret; +} + +SYSCALL_DEFINE2(inotify_rm_watch, int, fd, __s32, wd) +{ + struct fsnotify_group *group; + struct inotify_inode_mark *i_mark; + struct fd f; + int ret = -EINVAL; + + f = fdget(fd); + if (unlikely(!f.file)) + return -EBADF; + + /* verify that this is indeed an inotify instance */ + if (unlikely(f.file->f_op != &inotify_fops)) + goto out; + + group = f.file->private_data; + + i_mark = inotify_idr_find(group, wd); + if (unlikely(!i_mark)) + goto out; + + ret = 0; + + fsnotify_destroy_mark(&i_mark->fsn_mark, group); + + /* match ref taken by inotify_idr_find */ + fsnotify_put_mark(&i_mark->fsn_mark); + +out: + fdput(f); + return ret; +} + +/* + * inotify_user_setup - Our initialization function. Note that we cannot return + * error because we have compiled-in VFS hooks. So an (unlikely) failure here + * must result in panic(). + */ +static int __init inotify_user_setup(void) +{ + unsigned long watches_max; + struct sysinfo si; + + si_meminfo(&si); + /* + * Allow up to 1% of addressable memory to be allocated for inotify + * watches (per user) limited to the range [8192, 1048576]. + */ + watches_max = (((si.totalram - si.totalhigh) / 100) << PAGE_SHIFT) / + INOTIFY_WATCH_COST; + watches_max = clamp(watches_max, 8192UL, 1048576UL); + + BUILD_BUG_ON(IN_ACCESS != FS_ACCESS); + BUILD_BUG_ON(IN_MODIFY != FS_MODIFY); + BUILD_BUG_ON(IN_ATTRIB != FS_ATTRIB); + BUILD_BUG_ON(IN_CLOSE_WRITE != FS_CLOSE_WRITE); + BUILD_BUG_ON(IN_CLOSE_NOWRITE != FS_CLOSE_NOWRITE); + BUILD_BUG_ON(IN_OPEN != FS_OPEN); + BUILD_BUG_ON(IN_MOVED_FROM != FS_MOVED_FROM); + BUILD_BUG_ON(IN_MOVED_TO != FS_MOVED_TO); + BUILD_BUG_ON(IN_CREATE != FS_CREATE); + BUILD_BUG_ON(IN_DELETE != FS_DELETE); + BUILD_BUG_ON(IN_DELETE_SELF != FS_DELETE_SELF); + BUILD_BUG_ON(IN_MOVE_SELF != FS_MOVE_SELF); + BUILD_BUG_ON(IN_UNMOUNT != FS_UNMOUNT); + BUILD_BUG_ON(IN_Q_OVERFLOW != FS_Q_OVERFLOW); + BUILD_BUG_ON(IN_IGNORED != FS_IN_IGNORED); + BUILD_BUG_ON(IN_ISDIR != FS_ISDIR); + + BUILD_BUG_ON(HWEIGHT32(ALL_INOTIFY_BITS) != 22); + + inotify_inode_mark_cachep = KMEM_CACHE(inotify_inode_mark, + SLAB_PANIC|SLAB_ACCOUNT); + + inotify_max_queued_events = 16384; + init_user_ns.ucount_max[UCOUNT_INOTIFY_INSTANCES] = 128; + init_user_ns.ucount_max[UCOUNT_INOTIFY_WATCHES] = watches_max; + inotify_sysctls_init(); + + return 0; +} +fs_initcall(inotify_user_setup); |