mirror of https://gitee.com/openkylin/linux.git
1287 lines
30 KiB
C
1287 lines
30 KiB
C
/*
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* POSIX message queues filesystem for Linux.
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*
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* Copyright (C) 2003,2004 Krzysztof Benedyczak (golbi@mat.uni.torun.pl)
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* Michal Wronski (michal.wronski@gmail.com)
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*
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* Spinlocks: Mohamed Abbas (abbas.mohamed@intel.com)
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* Lockless receive & send, fd based notify:
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* Manfred Spraul (manfred@colorfullife.com)
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*
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* Audit: George Wilson (ltcgcw@us.ibm.com)
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*
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* This file is released under the GPL.
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*/
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#include <linux/capability.h>
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#include <linux/init.h>
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#include <linux/pagemap.h>
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#include <linux/file.h>
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#include <linux/mount.h>
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#include <linux/namei.h>
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#include <linux/sysctl.h>
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#include <linux/poll.h>
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#include <linux/mqueue.h>
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#include <linux/msg.h>
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#include <linux/skbuff.h>
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#include <linux/netlink.h>
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#include <linux/syscalls.h>
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#include <linux/audit.h>
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#include <linux/signal.h>
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#include <linux/mutex.h>
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#include <net/sock.h>
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#include "util.h"
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#define MQUEUE_MAGIC 0x19800202
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#define DIRENT_SIZE 20
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#define FILENT_SIZE 80
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#define SEND 0
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#define RECV 1
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#define STATE_NONE 0
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#define STATE_PENDING 1
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#define STATE_READY 2
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/* used by sysctl */
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#define FS_MQUEUE 1
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#define CTL_QUEUESMAX 2
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#define CTL_MSGMAX 3
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#define CTL_MSGSIZEMAX 4
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/* default values */
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#define DFLT_QUEUESMAX 256 /* max number of message queues */
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#define DFLT_MSGMAX 10 /* max number of messages in each queue */
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#define HARD_MSGMAX (131072/sizeof(void*))
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#define DFLT_MSGSIZEMAX 8192 /* max message size */
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struct ext_wait_queue { /* queue of sleeping tasks */
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struct task_struct *task;
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struct list_head list;
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struct msg_msg *msg; /* ptr of loaded message */
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int state; /* one of STATE_* values */
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};
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struct mqueue_inode_info {
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spinlock_t lock;
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struct inode vfs_inode;
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wait_queue_head_t wait_q;
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struct msg_msg **messages;
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struct mq_attr attr;
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struct sigevent notify;
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struct pid* notify_owner;
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struct user_struct *user; /* user who created, for accounting */
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struct sock *notify_sock;
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struct sk_buff *notify_cookie;
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/* for tasks waiting for free space and messages, respectively */
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struct ext_wait_queue e_wait_q[2];
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unsigned long qsize; /* size of queue in memory (sum of all msgs) */
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};
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static const struct inode_operations mqueue_dir_inode_operations;
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static const struct file_operations mqueue_file_operations;
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static struct super_operations mqueue_super_ops;
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static void remove_notification(struct mqueue_inode_info *info);
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static spinlock_t mq_lock;
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static struct kmem_cache *mqueue_inode_cachep;
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static struct vfsmount *mqueue_mnt;
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static unsigned int queues_count;
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static unsigned int queues_max = DFLT_QUEUESMAX;
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static unsigned int msg_max = DFLT_MSGMAX;
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static unsigned int msgsize_max = DFLT_MSGSIZEMAX;
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static struct ctl_table_header * mq_sysctl_table;
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static inline struct mqueue_inode_info *MQUEUE_I(struct inode *inode)
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{
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return container_of(inode, struct mqueue_inode_info, vfs_inode);
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}
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static struct inode *mqueue_get_inode(struct super_block *sb, int mode,
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struct mq_attr *attr)
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{
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struct inode *inode;
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inode = new_inode(sb);
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if (inode) {
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inode->i_mode = mode;
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inode->i_uid = current->fsuid;
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inode->i_gid = current->fsgid;
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inode->i_blocks = 0;
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inode->i_mtime = inode->i_ctime = inode->i_atime =
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CURRENT_TIME;
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if (S_ISREG(mode)) {
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struct mqueue_inode_info *info;
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struct task_struct *p = current;
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struct user_struct *u = p->user;
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unsigned long mq_bytes, mq_msg_tblsz;
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inode->i_fop = &mqueue_file_operations;
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inode->i_size = FILENT_SIZE;
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/* mqueue specific info */
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info = MQUEUE_I(inode);
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spin_lock_init(&info->lock);
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init_waitqueue_head(&info->wait_q);
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INIT_LIST_HEAD(&info->e_wait_q[0].list);
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INIT_LIST_HEAD(&info->e_wait_q[1].list);
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info->messages = NULL;
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info->notify_owner = NULL;
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info->qsize = 0;
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info->user = NULL; /* set when all is ok */
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memset(&info->attr, 0, sizeof(info->attr));
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info->attr.mq_maxmsg = DFLT_MSGMAX;
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info->attr.mq_msgsize = DFLT_MSGSIZEMAX;
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if (attr) {
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info->attr.mq_maxmsg = attr->mq_maxmsg;
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info->attr.mq_msgsize = attr->mq_msgsize;
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}
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mq_msg_tblsz = info->attr.mq_maxmsg * sizeof(struct msg_msg *);
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mq_bytes = (mq_msg_tblsz +
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(info->attr.mq_maxmsg * info->attr.mq_msgsize));
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spin_lock(&mq_lock);
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if (u->mq_bytes + mq_bytes < u->mq_bytes ||
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u->mq_bytes + mq_bytes >
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p->signal->rlim[RLIMIT_MSGQUEUE].rlim_cur) {
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spin_unlock(&mq_lock);
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goto out_inode;
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}
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u->mq_bytes += mq_bytes;
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spin_unlock(&mq_lock);
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info->messages = kmalloc(mq_msg_tblsz, GFP_KERNEL);
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if (!info->messages) {
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spin_lock(&mq_lock);
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u->mq_bytes -= mq_bytes;
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spin_unlock(&mq_lock);
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goto out_inode;
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}
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/* all is ok */
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info->user = get_uid(u);
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} else if (S_ISDIR(mode)) {
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inc_nlink(inode);
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/* Some things misbehave if size == 0 on a directory */
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inode->i_size = 2 * DIRENT_SIZE;
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inode->i_op = &mqueue_dir_inode_operations;
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inode->i_fop = &simple_dir_operations;
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}
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}
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return inode;
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out_inode:
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make_bad_inode(inode);
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iput(inode);
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return NULL;
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}
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static int mqueue_fill_super(struct super_block *sb, void *data, int silent)
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{
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struct inode *inode;
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sb->s_blocksize = PAGE_CACHE_SIZE;
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sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
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sb->s_magic = MQUEUE_MAGIC;
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sb->s_op = &mqueue_super_ops;
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inode = mqueue_get_inode(sb, S_IFDIR | S_ISVTX | S_IRWXUGO, NULL);
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if (!inode)
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return -ENOMEM;
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sb->s_root = d_alloc_root(inode);
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if (!sb->s_root) {
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iput(inode);
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return -ENOMEM;
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}
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return 0;
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}
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static int mqueue_get_sb(struct file_system_type *fs_type,
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int flags, const char *dev_name,
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void *data, struct vfsmount *mnt)
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{
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return get_sb_single(fs_type, flags, data, mqueue_fill_super, mnt);
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}
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static void init_once(void *foo, struct kmem_cache * cachep, unsigned long flags)
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{
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struct mqueue_inode_info *p = (struct mqueue_inode_info *) foo;
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inode_init_once(&p->vfs_inode);
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}
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static struct inode *mqueue_alloc_inode(struct super_block *sb)
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{
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struct mqueue_inode_info *ei;
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ei = kmem_cache_alloc(mqueue_inode_cachep, GFP_KERNEL);
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if (!ei)
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return NULL;
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return &ei->vfs_inode;
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}
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static void mqueue_destroy_inode(struct inode *inode)
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{
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kmem_cache_free(mqueue_inode_cachep, MQUEUE_I(inode));
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}
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static void mqueue_delete_inode(struct inode *inode)
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{
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struct mqueue_inode_info *info;
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struct user_struct *user;
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unsigned long mq_bytes;
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int i;
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if (S_ISDIR(inode->i_mode)) {
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clear_inode(inode);
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return;
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}
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info = MQUEUE_I(inode);
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spin_lock(&info->lock);
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for (i = 0; i < info->attr.mq_curmsgs; i++)
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free_msg(info->messages[i]);
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kfree(info->messages);
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spin_unlock(&info->lock);
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clear_inode(inode);
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mq_bytes = (info->attr.mq_maxmsg * sizeof(struct msg_msg *) +
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(info->attr.mq_maxmsg * info->attr.mq_msgsize));
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user = info->user;
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if (user) {
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spin_lock(&mq_lock);
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user->mq_bytes -= mq_bytes;
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queues_count--;
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spin_unlock(&mq_lock);
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free_uid(user);
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}
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}
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static int mqueue_create(struct inode *dir, struct dentry *dentry,
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int mode, struct nameidata *nd)
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{
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struct inode *inode;
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struct mq_attr *attr = dentry->d_fsdata;
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int error;
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spin_lock(&mq_lock);
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if (queues_count >= queues_max && !capable(CAP_SYS_RESOURCE)) {
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error = -ENOSPC;
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goto out_lock;
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}
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queues_count++;
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spin_unlock(&mq_lock);
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inode = mqueue_get_inode(dir->i_sb, mode, attr);
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if (!inode) {
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error = -ENOMEM;
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spin_lock(&mq_lock);
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queues_count--;
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goto out_lock;
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}
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dir->i_size += DIRENT_SIZE;
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dir->i_ctime = dir->i_mtime = dir->i_atime = CURRENT_TIME;
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d_instantiate(dentry, inode);
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dget(dentry);
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return 0;
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out_lock:
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spin_unlock(&mq_lock);
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return error;
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}
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static int mqueue_unlink(struct inode *dir, struct dentry *dentry)
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{
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struct inode *inode = dentry->d_inode;
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dir->i_ctime = dir->i_mtime = dir->i_atime = CURRENT_TIME;
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dir->i_size -= DIRENT_SIZE;
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drop_nlink(inode);
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dput(dentry);
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return 0;
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}
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/*
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* This is routine for system read from queue file.
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* To avoid mess with doing here some sort of mq_receive we allow
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* to read only queue size & notification info (the only values
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* that are interesting from user point of view and aren't accessible
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* through std routines)
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*/
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static ssize_t mqueue_read_file(struct file *filp, char __user *u_data,
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size_t count, loff_t * off)
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{
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struct mqueue_inode_info *info = MQUEUE_I(filp->f_path.dentry->d_inode);
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char buffer[FILENT_SIZE];
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size_t slen;
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loff_t o;
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if (!count)
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return 0;
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spin_lock(&info->lock);
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snprintf(buffer, sizeof(buffer),
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"QSIZE:%-10lu NOTIFY:%-5d SIGNO:%-5d NOTIFY_PID:%-6d\n",
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info->qsize,
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info->notify_owner ? info->notify.sigev_notify : 0,
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(info->notify_owner &&
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info->notify.sigev_notify == SIGEV_SIGNAL) ?
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info->notify.sigev_signo : 0,
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pid_nr(info->notify_owner));
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spin_unlock(&info->lock);
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buffer[sizeof(buffer)-1] = '\0';
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slen = strlen(buffer)+1;
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o = *off;
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if (o > slen)
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return 0;
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if (o + count > slen)
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count = slen - o;
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if (copy_to_user(u_data, buffer + o, count))
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return -EFAULT;
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*off = o + count;
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filp->f_path.dentry->d_inode->i_atime = filp->f_path.dentry->d_inode->i_ctime = CURRENT_TIME;
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return count;
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}
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static int mqueue_flush_file(struct file *filp, fl_owner_t id)
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{
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struct mqueue_inode_info *info = MQUEUE_I(filp->f_path.dentry->d_inode);
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spin_lock(&info->lock);
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if (task_tgid(current) == info->notify_owner)
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remove_notification(info);
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spin_unlock(&info->lock);
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return 0;
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}
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static unsigned int mqueue_poll_file(struct file *filp, struct poll_table_struct *poll_tab)
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{
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struct mqueue_inode_info *info = MQUEUE_I(filp->f_path.dentry->d_inode);
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int retval = 0;
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poll_wait(filp, &info->wait_q, poll_tab);
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spin_lock(&info->lock);
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if (info->attr.mq_curmsgs)
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retval = POLLIN | POLLRDNORM;
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if (info->attr.mq_curmsgs < info->attr.mq_maxmsg)
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retval |= POLLOUT | POLLWRNORM;
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spin_unlock(&info->lock);
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return retval;
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}
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/* Adds current to info->e_wait_q[sr] before element with smaller prio */
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static void wq_add(struct mqueue_inode_info *info, int sr,
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struct ext_wait_queue *ewp)
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{
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struct ext_wait_queue *walk;
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ewp->task = current;
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list_for_each_entry(walk, &info->e_wait_q[sr].list, list) {
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if (walk->task->static_prio <= current->static_prio) {
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list_add_tail(&ewp->list, &walk->list);
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return;
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}
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}
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list_add_tail(&ewp->list, &info->e_wait_q[sr].list);
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}
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/*
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* Puts current task to sleep. Caller must hold queue lock. After return
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* lock isn't held.
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* sr: SEND or RECV
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*/
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static int wq_sleep(struct mqueue_inode_info *info, int sr,
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long timeout, struct ext_wait_queue *ewp)
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{
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int retval;
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signed long time;
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wq_add(info, sr, ewp);
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for (;;) {
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set_current_state(TASK_INTERRUPTIBLE);
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spin_unlock(&info->lock);
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time = schedule_timeout(timeout);
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while (ewp->state == STATE_PENDING)
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cpu_relax();
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if (ewp->state == STATE_READY) {
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retval = 0;
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goto out;
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}
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spin_lock(&info->lock);
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if (ewp->state == STATE_READY) {
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retval = 0;
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goto out_unlock;
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}
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if (signal_pending(current)) {
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retval = -ERESTARTSYS;
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break;
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}
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if (time == 0) {
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retval = -ETIMEDOUT;
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break;
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}
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}
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list_del(&ewp->list);
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out_unlock:
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spin_unlock(&info->lock);
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out:
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return retval;
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}
|
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|
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/*
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* Returns waiting task that should be serviced first or NULL if none exists
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*/
|
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static struct ext_wait_queue *wq_get_first_waiter(
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struct mqueue_inode_info *info, int sr)
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{
|
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struct list_head *ptr;
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|
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ptr = info->e_wait_q[sr].list.prev;
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if (ptr == &info->e_wait_q[sr].list)
|
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return NULL;
|
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return list_entry(ptr, struct ext_wait_queue, list);
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}
|
|
|
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/* Auxiliary functions to manipulate messages' list */
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static void msg_insert(struct msg_msg *ptr, struct mqueue_inode_info *info)
|
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{
|
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int k;
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|
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k = info->attr.mq_curmsgs - 1;
|
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while (k >= 0 && info->messages[k]->m_type >= ptr->m_type) {
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info->messages[k + 1] = info->messages[k];
|
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k--;
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}
|
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info->attr.mq_curmsgs++;
|
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info->qsize += ptr->m_ts;
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info->messages[k + 1] = ptr;
|
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}
|
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|
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static inline struct msg_msg *msg_get(struct mqueue_inode_info *info)
|
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{
|
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info->qsize -= info->messages[--info->attr.mq_curmsgs]->m_ts;
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return info->messages[info->attr.mq_curmsgs];
|
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}
|
|
|
|
static inline void set_cookie(struct sk_buff *skb, char code)
|
|
{
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((char*)skb->data)[NOTIFY_COOKIE_LEN-1] = code;
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}
|
|
|
|
/*
|
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* The next function is only to split too long sys_mq_timedsend
|
|
*/
|
|
static void __do_notify(struct mqueue_inode_info *info)
|
|
{
|
|
/* notification
|
|
* invoked when there is registered process and there isn't process
|
|
* waiting synchronously for message AND state of queue changed from
|
|
* empty to not empty. Here we are sure that no one is waiting
|
|
* synchronously. */
|
|
if (info->notify_owner &&
|
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info->attr.mq_curmsgs == 1) {
|
|
struct siginfo sig_i;
|
|
switch (info->notify.sigev_notify) {
|
|
case SIGEV_NONE:
|
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break;
|
|
case SIGEV_SIGNAL:
|
|
/* sends signal */
|
|
|
|
sig_i.si_signo = info->notify.sigev_signo;
|
|
sig_i.si_errno = 0;
|
|
sig_i.si_code = SI_MESGQ;
|
|
sig_i.si_value = info->notify.sigev_value;
|
|
sig_i.si_pid = current->tgid;
|
|
sig_i.si_uid = current->uid;
|
|
|
|
kill_pid_info(info->notify.sigev_signo,
|
|
&sig_i, info->notify_owner);
|
|
break;
|
|
case SIGEV_THREAD:
|
|
set_cookie(info->notify_cookie, NOTIFY_WOKENUP);
|
|
netlink_sendskb(info->notify_sock, info->notify_cookie);
|
|
break;
|
|
}
|
|
/* after notification unregisters process */
|
|
put_pid(info->notify_owner);
|
|
info->notify_owner = NULL;
|
|
}
|
|
wake_up(&info->wait_q);
|
|
}
|
|
|
|
static long prepare_timeout(const struct timespec __user *u_arg)
|
|
{
|
|
struct timespec ts, nowts;
|
|
long timeout;
|
|
|
|
if (u_arg) {
|
|
if (unlikely(copy_from_user(&ts, u_arg,
|
|
sizeof(struct timespec))))
|
|
return -EFAULT;
|
|
|
|
if (unlikely(ts.tv_nsec < 0 || ts.tv_sec < 0
|
|
|| ts.tv_nsec >= NSEC_PER_SEC))
|
|
return -EINVAL;
|
|
nowts = CURRENT_TIME;
|
|
/* first subtract as jiffies can't be too big */
|
|
ts.tv_sec -= nowts.tv_sec;
|
|
if (ts.tv_nsec < nowts.tv_nsec) {
|
|
ts.tv_nsec += NSEC_PER_SEC;
|
|
ts.tv_sec--;
|
|
}
|
|
ts.tv_nsec -= nowts.tv_nsec;
|
|
if (ts.tv_sec < 0)
|
|
return 0;
|
|
|
|
timeout = timespec_to_jiffies(&ts) + 1;
|
|
} else
|
|
return MAX_SCHEDULE_TIMEOUT;
|
|
|
|
return timeout;
|
|
}
|
|
|
|
static void remove_notification(struct mqueue_inode_info *info)
|
|
{
|
|
if (info->notify_owner != NULL &&
|
|
info->notify.sigev_notify == SIGEV_THREAD) {
|
|
set_cookie(info->notify_cookie, NOTIFY_REMOVED);
|
|
netlink_sendskb(info->notify_sock, info->notify_cookie);
|
|
}
|
|
put_pid(info->notify_owner);
|
|
info->notify_owner = NULL;
|
|
}
|
|
|
|
static int mq_attr_ok(struct mq_attr *attr)
|
|
{
|
|
if (attr->mq_maxmsg <= 0 || attr->mq_msgsize <= 0)
|
|
return 0;
|
|
if (capable(CAP_SYS_RESOURCE)) {
|
|
if (attr->mq_maxmsg > HARD_MSGMAX)
|
|
return 0;
|
|
} else {
|
|
if (attr->mq_maxmsg > msg_max ||
|
|
attr->mq_msgsize > msgsize_max)
|
|
return 0;
|
|
}
|
|
/* check for overflow */
|
|
if (attr->mq_msgsize > ULONG_MAX/attr->mq_maxmsg)
|
|
return 0;
|
|
if ((unsigned long)(attr->mq_maxmsg * attr->mq_msgsize) +
|
|
(attr->mq_maxmsg * sizeof (struct msg_msg *)) <
|
|
(unsigned long)(attr->mq_maxmsg * attr->mq_msgsize))
|
|
return 0;
|
|
return 1;
|
|
}
|
|
|
|
/*
|
|
* Invoked when creating a new queue via sys_mq_open
|
|
*/
|
|
static struct file *do_create(struct dentry *dir, struct dentry *dentry,
|
|
int oflag, mode_t mode, struct mq_attr __user *u_attr)
|
|
{
|
|
struct mq_attr attr;
|
|
int ret;
|
|
|
|
if (u_attr) {
|
|
ret = -EFAULT;
|
|
if (copy_from_user(&attr, u_attr, sizeof(attr)))
|
|
goto out;
|
|
ret = -EINVAL;
|
|
if (!mq_attr_ok(&attr))
|
|
goto out;
|
|
/* store for use during create */
|
|
dentry->d_fsdata = &attr;
|
|
}
|
|
|
|
mode &= ~current->fs->umask;
|
|
ret = vfs_create(dir->d_inode, dentry, mode, NULL);
|
|
dentry->d_fsdata = NULL;
|
|
if (ret)
|
|
goto out;
|
|
|
|
return dentry_open(dentry, mqueue_mnt, oflag);
|
|
|
|
out:
|
|
dput(dentry);
|
|
mntput(mqueue_mnt);
|
|
return ERR_PTR(ret);
|
|
}
|
|
|
|
/* Opens existing queue */
|
|
static struct file *do_open(struct dentry *dentry, int oflag)
|
|
{
|
|
static int oflag2acc[O_ACCMODE] = { MAY_READ, MAY_WRITE,
|
|
MAY_READ | MAY_WRITE };
|
|
|
|
if ((oflag & O_ACCMODE) == (O_RDWR | O_WRONLY)) {
|
|
dput(dentry);
|
|
mntput(mqueue_mnt);
|
|
return ERR_PTR(-EINVAL);
|
|
}
|
|
|
|
if (permission(dentry->d_inode, oflag2acc[oflag & O_ACCMODE], NULL)) {
|
|
dput(dentry);
|
|
mntput(mqueue_mnt);
|
|
return ERR_PTR(-EACCES);
|
|
}
|
|
|
|
return dentry_open(dentry, mqueue_mnt, oflag);
|
|
}
|
|
|
|
asmlinkage long sys_mq_open(const char __user *u_name, int oflag, mode_t mode,
|
|
struct mq_attr __user *u_attr)
|
|
{
|
|
struct dentry *dentry;
|
|
struct file *filp;
|
|
char *name;
|
|
int fd, error;
|
|
|
|
error = audit_mq_open(oflag, mode, u_attr);
|
|
if (error != 0)
|
|
return error;
|
|
|
|
if (IS_ERR(name = getname(u_name)))
|
|
return PTR_ERR(name);
|
|
|
|
fd = get_unused_fd();
|
|
if (fd < 0)
|
|
goto out_putname;
|
|
|
|
mutex_lock(&mqueue_mnt->mnt_root->d_inode->i_mutex);
|
|
dentry = lookup_one_len(name, mqueue_mnt->mnt_root, strlen(name));
|
|
if (IS_ERR(dentry)) {
|
|
error = PTR_ERR(dentry);
|
|
goto out_err;
|
|
}
|
|
mntget(mqueue_mnt);
|
|
|
|
if (oflag & O_CREAT) {
|
|
if (dentry->d_inode) { /* entry already exists */
|
|
audit_inode(name, dentry->d_inode);
|
|
error = -EEXIST;
|
|
if (oflag & O_EXCL)
|
|
goto out;
|
|
filp = do_open(dentry, oflag);
|
|
} else {
|
|
filp = do_create(mqueue_mnt->mnt_root, dentry,
|
|
oflag, mode, u_attr);
|
|
}
|
|
} else {
|
|
error = -ENOENT;
|
|
if (!dentry->d_inode)
|
|
goto out;
|
|
audit_inode(name, dentry->d_inode);
|
|
filp = do_open(dentry, oflag);
|
|
}
|
|
|
|
if (IS_ERR(filp)) {
|
|
error = PTR_ERR(filp);
|
|
goto out_putfd;
|
|
}
|
|
|
|
set_close_on_exec(fd, 1);
|
|
fd_install(fd, filp);
|
|
goto out_upsem;
|
|
|
|
out:
|
|
dput(dentry);
|
|
mntput(mqueue_mnt);
|
|
out_putfd:
|
|
put_unused_fd(fd);
|
|
out_err:
|
|
fd = error;
|
|
out_upsem:
|
|
mutex_unlock(&mqueue_mnt->mnt_root->d_inode->i_mutex);
|
|
out_putname:
|
|
putname(name);
|
|
return fd;
|
|
}
|
|
|
|
asmlinkage long sys_mq_unlink(const char __user *u_name)
|
|
{
|
|
int err;
|
|
char *name;
|
|
struct dentry *dentry;
|
|
struct inode *inode = NULL;
|
|
|
|
name = getname(u_name);
|
|
if (IS_ERR(name))
|
|
return PTR_ERR(name);
|
|
|
|
mutex_lock_nested(&mqueue_mnt->mnt_root->d_inode->i_mutex,
|
|
I_MUTEX_PARENT);
|
|
dentry = lookup_one_len(name, mqueue_mnt->mnt_root, strlen(name));
|
|
if (IS_ERR(dentry)) {
|
|
err = PTR_ERR(dentry);
|
|
goto out_unlock;
|
|
}
|
|
|
|
if (!dentry->d_inode) {
|
|
err = -ENOENT;
|
|
goto out_err;
|
|
}
|
|
|
|
inode = dentry->d_inode;
|
|
if (inode)
|
|
atomic_inc(&inode->i_count);
|
|
|
|
err = vfs_unlink(dentry->d_parent->d_inode, dentry);
|
|
out_err:
|
|
dput(dentry);
|
|
|
|
out_unlock:
|
|
mutex_unlock(&mqueue_mnt->mnt_root->d_inode->i_mutex);
|
|
putname(name);
|
|
if (inode)
|
|
iput(inode);
|
|
|
|
return err;
|
|
}
|
|
|
|
/* Pipelined send and receive functions.
|
|
*
|
|
* If a receiver finds no waiting message, then it registers itself in the
|
|
* list of waiting receivers. A sender checks that list before adding the new
|
|
* message into the message array. If there is a waiting receiver, then it
|
|
* bypasses the message array and directly hands the message over to the
|
|
* receiver.
|
|
* The receiver accepts the message and returns without grabbing the queue
|
|
* spinlock. Therefore an intermediate STATE_PENDING state and memory barriers
|
|
* are necessary. The same algorithm is used for sysv semaphores, see
|
|
* ipc/sem.c for more details.
|
|
*
|
|
* The same algorithm is used for senders.
|
|
*/
|
|
|
|
/* pipelined_send() - send a message directly to the task waiting in
|
|
* sys_mq_timedreceive() (without inserting message into a queue).
|
|
*/
|
|
static inline void pipelined_send(struct mqueue_inode_info *info,
|
|
struct msg_msg *message,
|
|
struct ext_wait_queue *receiver)
|
|
{
|
|
receiver->msg = message;
|
|
list_del(&receiver->list);
|
|
receiver->state = STATE_PENDING;
|
|
wake_up_process(receiver->task);
|
|
smp_wmb();
|
|
receiver->state = STATE_READY;
|
|
}
|
|
|
|
/* pipelined_receive() - if there is task waiting in sys_mq_timedsend()
|
|
* gets its message and put to the queue (we have one free place for sure). */
|
|
static inline void pipelined_receive(struct mqueue_inode_info *info)
|
|
{
|
|
struct ext_wait_queue *sender = wq_get_first_waiter(info, SEND);
|
|
|
|
if (!sender) {
|
|
/* for poll */
|
|
wake_up_interruptible(&info->wait_q);
|
|
return;
|
|
}
|
|
msg_insert(sender->msg, info);
|
|
list_del(&sender->list);
|
|
sender->state = STATE_PENDING;
|
|
wake_up_process(sender->task);
|
|
smp_wmb();
|
|
sender->state = STATE_READY;
|
|
}
|
|
|
|
asmlinkage long sys_mq_timedsend(mqd_t mqdes, const char __user *u_msg_ptr,
|
|
size_t msg_len, unsigned int msg_prio,
|
|
const struct timespec __user *u_abs_timeout)
|
|
{
|
|
struct file *filp;
|
|
struct inode *inode;
|
|
struct ext_wait_queue wait;
|
|
struct ext_wait_queue *receiver;
|
|
struct msg_msg *msg_ptr;
|
|
struct mqueue_inode_info *info;
|
|
long timeout;
|
|
int ret;
|
|
|
|
ret = audit_mq_timedsend(mqdes, msg_len, msg_prio, u_abs_timeout);
|
|
if (ret != 0)
|
|
return ret;
|
|
|
|
if (unlikely(msg_prio >= (unsigned long) MQ_PRIO_MAX))
|
|
return -EINVAL;
|
|
|
|
timeout = prepare_timeout(u_abs_timeout);
|
|
|
|
ret = -EBADF;
|
|
filp = fget(mqdes);
|
|
if (unlikely(!filp))
|
|
goto out;
|
|
|
|
inode = filp->f_path.dentry->d_inode;
|
|
if (unlikely(filp->f_op != &mqueue_file_operations))
|
|
goto out_fput;
|
|
info = MQUEUE_I(inode);
|
|
audit_inode(NULL, inode);
|
|
|
|
if (unlikely(!(filp->f_mode & FMODE_WRITE)))
|
|
goto out_fput;
|
|
|
|
if (unlikely(msg_len > info->attr.mq_msgsize)) {
|
|
ret = -EMSGSIZE;
|
|
goto out_fput;
|
|
}
|
|
|
|
/* First try to allocate memory, before doing anything with
|
|
* existing queues. */
|
|
msg_ptr = load_msg(u_msg_ptr, msg_len);
|
|
if (IS_ERR(msg_ptr)) {
|
|
ret = PTR_ERR(msg_ptr);
|
|
goto out_fput;
|
|
}
|
|
msg_ptr->m_ts = msg_len;
|
|
msg_ptr->m_type = msg_prio;
|
|
|
|
spin_lock(&info->lock);
|
|
|
|
if (info->attr.mq_curmsgs == info->attr.mq_maxmsg) {
|
|
if (filp->f_flags & O_NONBLOCK) {
|
|
spin_unlock(&info->lock);
|
|
ret = -EAGAIN;
|
|
} else if (unlikely(timeout < 0)) {
|
|
spin_unlock(&info->lock);
|
|
ret = timeout;
|
|
} else {
|
|
wait.task = current;
|
|
wait.msg = (void *) msg_ptr;
|
|
wait.state = STATE_NONE;
|
|
ret = wq_sleep(info, SEND, timeout, &wait);
|
|
}
|
|
if (ret < 0)
|
|
free_msg(msg_ptr);
|
|
} else {
|
|
receiver = wq_get_first_waiter(info, RECV);
|
|
if (receiver) {
|
|
pipelined_send(info, msg_ptr, receiver);
|
|
} else {
|
|
/* adds message to the queue */
|
|
msg_insert(msg_ptr, info);
|
|
__do_notify(info);
|
|
}
|
|
inode->i_atime = inode->i_mtime = inode->i_ctime =
|
|
CURRENT_TIME;
|
|
spin_unlock(&info->lock);
|
|
ret = 0;
|
|
}
|
|
out_fput:
|
|
fput(filp);
|
|
out:
|
|
return ret;
|
|
}
|
|
|
|
asmlinkage ssize_t sys_mq_timedreceive(mqd_t mqdes, char __user *u_msg_ptr,
|
|
size_t msg_len, unsigned int __user *u_msg_prio,
|
|
const struct timespec __user *u_abs_timeout)
|
|
{
|
|
long timeout;
|
|
ssize_t ret;
|
|
struct msg_msg *msg_ptr;
|
|
struct file *filp;
|
|
struct inode *inode;
|
|
struct mqueue_inode_info *info;
|
|
struct ext_wait_queue wait;
|
|
|
|
ret = audit_mq_timedreceive(mqdes, msg_len, u_msg_prio, u_abs_timeout);
|
|
if (ret != 0)
|
|
return ret;
|
|
|
|
timeout = prepare_timeout(u_abs_timeout);
|
|
|
|
ret = -EBADF;
|
|
filp = fget(mqdes);
|
|
if (unlikely(!filp))
|
|
goto out;
|
|
|
|
inode = filp->f_path.dentry->d_inode;
|
|
if (unlikely(filp->f_op != &mqueue_file_operations))
|
|
goto out_fput;
|
|
info = MQUEUE_I(inode);
|
|
audit_inode(NULL, inode);
|
|
|
|
if (unlikely(!(filp->f_mode & FMODE_READ)))
|
|
goto out_fput;
|
|
|
|
/* checks if buffer is big enough */
|
|
if (unlikely(msg_len < info->attr.mq_msgsize)) {
|
|
ret = -EMSGSIZE;
|
|
goto out_fput;
|
|
}
|
|
|
|
spin_lock(&info->lock);
|
|
if (info->attr.mq_curmsgs == 0) {
|
|
if (filp->f_flags & O_NONBLOCK) {
|
|
spin_unlock(&info->lock);
|
|
ret = -EAGAIN;
|
|
msg_ptr = NULL;
|
|
} else if (unlikely(timeout < 0)) {
|
|
spin_unlock(&info->lock);
|
|
ret = timeout;
|
|
msg_ptr = NULL;
|
|
} else {
|
|
wait.task = current;
|
|
wait.state = STATE_NONE;
|
|
ret = wq_sleep(info, RECV, timeout, &wait);
|
|
msg_ptr = wait.msg;
|
|
}
|
|
} else {
|
|
msg_ptr = msg_get(info);
|
|
|
|
inode->i_atime = inode->i_mtime = inode->i_ctime =
|
|
CURRENT_TIME;
|
|
|
|
/* There is now free space in queue. */
|
|
pipelined_receive(info);
|
|
spin_unlock(&info->lock);
|
|
ret = 0;
|
|
}
|
|
if (ret == 0) {
|
|
ret = msg_ptr->m_ts;
|
|
|
|
if ((u_msg_prio && put_user(msg_ptr->m_type, u_msg_prio)) ||
|
|
store_msg(u_msg_ptr, msg_ptr, msg_ptr->m_ts)) {
|
|
ret = -EFAULT;
|
|
}
|
|
free_msg(msg_ptr);
|
|
}
|
|
out_fput:
|
|
fput(filp);
|
|
out:
|
|
return ret;
|
|
}
|
|
|
|
/*
|
|
* Notes: the case when user wants us to deregister (with NULL as pointer)
|
|
* and he isn't currently owner of notification, will be silently discarded.
|
|
* It isn't explicitly defined in the POSIX.
|
|
*/
|
|
asmlinkage long sys_mq_notify(mqd_t mqdes,
|
|
const struct sigevent __user *u_notification)
|
|
{
|
|
int ret;
|
|
struct file *filp;
|
|
struct sock *sock;
|
|
struct inode *inode;
|
|
struct sigevent notification;
|
|
struct mqueue_inode_info *info;
|
|
struct sk_buff *nc;
|
|
|
|
ret = audit_mq_notify(mqdes, u_notification);
|
|
if (ret != 0)
|
|
return ret;
|
|
|
|
nc = NULL;
|
|
sock = NULL;
|
|
if (u_notification != NULL) {
|
|
if (copy_from_user(¬ification, u_notification,
|
|
sizeof(struct sigevent)))
|
|
return -EFAULT;
|
|
|
|
if (unlikely(notification.sigev_notify != SIGEV_NONE &&
|
|
notification.sigev_notify != SIGEV_SIGNAL &&
|
|
notification.sigev_notify != SIGEV_THREAD))
|
|
return -EINVAL;
|
|
if (notification.sigev_notify == SIGEV_SIGNAL &&
|
|
!valid_signal(notification.sigev_signo)) {
|
|
return -EINVAL;
|
|
}
|
|
if (notification.sigev_notify == SIGEV_THREAD) {
|
|
/* create the notify skb */
|
|
nc = alloc_skb(NOTIFY_COOKIE_LEN, GFP_KERNEL);
|
|
ret = -ENOMEM;
|
|
if (!nc)
|
|
goto out;
|
|
ret = -EFAULT;
|
|
if (copy_from_user(nc->data,
|
|
notification.sigev_value.sival_ptr,
|
|
NOTIFY_COOKIE_LEN)) {
|
|
goto out;
|
|
}
|
|
|
|
/* TODO: add a header? */
|
|
skb_put(nc, NOTIFY_COOKIE_LEN);
|
|
/* and attach it to the socket */
|
|
retry:
|
|
filp = fget(notification.sigev_signo);
|
|
ret = -EBADF;
|
|
if (!filp)
|
|
goto out;
|
|
sock = netlink_getsockbyfilp(filp);
|
|
fput(filp);
|
|
if (IS_ERR(sock)) {
|
|
ret = PTR_ERR(sock);
|
|
sock = NULL;
|
|
goto out;
|
|
}
|
|
|
|
ret = netlink_attachskb(sock, nc, 0,
|
|
MAX_SCHEDULE_TIMEOUT, NULL);
|
|
if (ret == 1)
|
|
goto retry;
|
|
if (ret) {
|
|
sock = NULL;
|
|
nc = NULL;
|
|
goto out;
|
|
}
|
|
}
|
|
}
|
|
|
|
ret = -EBADF;
|
|
filp = fget(mqdes);
|
|
if (!filp)
|
|
goto out;
|
|
|
|
inode = filp->f_path.dentry->d_inode;
|
|
if (unlikely(filp->f_op != &mqueue_file_operations))
|
|
goto out_fput;
|
|
info = MQUEUE_I(inode);
|
|
|
|
ret = 0;
|
|
spin_lock(&info->lock);
|
|
if (u_notification == NULL) {
|
|
if (info->notify_owner == task_tgid(current)) {
|
|
remove_notification(info);
|
|
inode->i_atime = inode->i_ctime = CURRENT_TIME;
|
|
}
|
|
} else if (info->notify_owner != NULL) {
|
|
ret = -EBUSY;
|
|
} else {
|
|
switch (notification.sigev_notify) {
|
|
case SIGEV_NONE:
|
|
info->notify.sigev_notify = SIGEV_NONE;
|
|
break;
|
|
case SIGEV_THREAD:
|
|
info->notify_sock = sock;
|
|
info->notify_cookie = nc;
|
|
sock = NULL;
|
|
nc = NULL;
|
|
info->notify.sigev_notify = SIGEV_THREAD;
|
|
break;
|
|
case SIGEV_SIGNAL:
|
|
info->notify.sigev_signo = notification.sigev_signo;
|
|
info->notify.sigev_value = notification.sigev_value;
|
|
info->notify.sigev_notify = SIGEV_SIGNAL;
|
|
break;
|
|
}
|
|
|
|
info->notify_owner = get_pid(task_tgid(current));
|
|
inode->i_atime = inode->i_ctime = CURRENT_TIME;
|
|
}
|
|
spin_unlock(&info->lock);
|
|
out_fput:
|
|
fput(filp);
|
|
out:
|
|
if (sock) {
|
|
netlink_detachskb(sock, nc);
|
|
} else if (nc) {
|
|
dev_kfree_skb(nc);
|
|
}
|
|
return ret;
|
|
}
|
|
|
|
asmlinkage long sys_mq_getsetattr(mqd_t mqdes,
|
|
const struct mq_attr __user *u_mqstat,
|
|
struct mq_attr __user *u_omqstat)
|
|
{
|
|
int ret;
|
|
struct mq_attr mqstat, omqstat;
|
|
struct file *filp;
|
|
struct inode *inode;
|
|
struct mqueue_inode_info *info;
|
|
|
|
if (u_mqstat != NULL) {
|
|
if (copy_from_user(&mqstat, u_mqstat, sizeof(struct mq_attr)))
|
|
return -EFAULT;
|
|
if (mqstat.mq_flags & (~O_NONBLOCK))
|
|
return -EINVAL;
|
|
}
|
|
|
|
ret = -EBADF;
|
|
filp = fget(mqdes);
|
|
if (!filp)
|
|
goto out;
|
|
|
|
inode = filp->f_path.dentry->d_inode;
|
|
if (unlikely(filp->f_op != &mqueue_file_operations))
|
|
goto out_fput;
|
|
info = MQUEUE_I(inode);
|
|
|
|
spin_lock(&info->lock);
|
|
|
|
omqstat = info->attr;
|
|
omqstat.mq_flags = filp->f_flags & O_NONBLOCK;
|
|
if (u_mqstat) {
|
|
ret = audit_mq_getsetattr(mqdes, &mqstat);
|
|
if (ret != 0)
|
|
goto out;
|
|
if (mqstat.mq_flags & O_NONBLOCK)
|
|
filp->f_flags |= O_NONBLOCK;
|
|
else
|
|
filp->f_flags &= ~O_NONBLOCK;
|
|
|
|
inode->i_atime = inode->i_ctime = CURRENT_TIME;
|
|
}
|
|
|
|
spin_unlock(&info->lock);
|
|
|
|
ret = 0;
|
|
if (u_omqstat != NULL && copy_to_user(u_omqstat, &omqstat,
|
|
sizeof(struct mq_attr)))
|
|
ret = -EFAULT;
|
|
|
|
out_fput:
|
|
fput(filp);
|
|
out:
|
|
return ret;
|
|
}
|
|
|
|
static const struct inode_operations mqueue_dir_inode_operations = {
|
|
.lookup = simple_lookup,
|
|
.create = mqueue_create,
|
|
.unlink = mqueue_unlink,
|
|
};
|
|
|
|
static const struct file_operations mqueue_file_operations = {
|
|
.flush = mqueue_flush_file,
|
|
.poll = mqueue_poll_file,
|
|
.read = mqueue_read_file,
|
|
};
|
|
|
|
static struct super_operations mqueue_super_ops = {
|
|
.alloc_inode = mqueue_alloc_inode,
|
|
.destroy_inode = mqueue_destroy_inode,
|
|
.statfs = simple_statfs,
|
|
.delete_inode = mqueue_delete_inode,
|
|
.drop_inode = generic_delete_inode,
|
|
};
|
|
|
|
static struct file_system_type mqueue_fs_type = {
|
|
.name = "mqueue",
|
|
.get_sb = mqueue_get_sb,
|
|
.kill_sb = kill_litter_super,
|
|
};
|
|
|
|
static int msg_max_limit_min = DFLT_MSGMAX;
|
|
static int msg_max_limit_max = HARD_MSGMAX;
|
|
|
|
static int msg_maxsize_limit_min = DFLT_MSGSIZEMAX;
|
|
static int msg_maxsize_limit_max = INT_MAX;
|
|
|
|
static ctl_table mq_sysctls[] = {
|
|
{
|
|
.ctl_name = CTL_QUEUESMAX,
|
|
.procname = "queues_max",
|
|
.data = &queues_max,
|
|
.maxlen = sizeof(int),
|
|
.mode = 0644,
|
|
.proc_handler = &proc_dointvec,
|
|
},
|
|
{
|
|
.ctl_name = CTL_MSGMAX,
|
|
.procname = "msg_max",
|
|
.data = &msg_max,
|
|
.maxlen = sizeof(int),
|
|
.mode = 0644,
|
|
.proc_handler = &proc_dointvec_minmax,
|
|
.extra1 = &msg_max_limit_min,
|
|
.extra2 = &msg_max_limit_max,
|
|
},
|
|
{
|
|
.ctl_name = CTL_MSGSIZEMAX,
|
|
.procname = "msgsize_max",
|
|
.data = &msgsize_max,
|
|
.maxlen = sizeof(int),
|
|
.mode = 0644,
|
|
.proc_handler = &proc_dointvec_minmax,
|
|
.extra1 = &msg_maxsize_limit_min,
|
|
.extra2 = &msg_maxsize_limit_max,
|
|
},
|
|
{ .ctl_name = 0 }
|
|
};
|
|
|
|
static ctl_table mq_sysctl_dir[] = {
|
|
{
|
|
.ctl_name = FS_MQUEUE,
|
|
.procname = "mqueue",
|
|
.mode = 0555,
|
|
.child = mq_sysctls,
|
|
},
|
|
{ .ctl_name = 0 }
|
|
};
|
|
|
|
static ctl_table mq_sysctl_root[] = {
|
|
{
|
|
.ctl_name = CTL_FS,
|
|
.procname = "fs",
|
|
.mode = 0555,
|
|
.child = mq_sysctl_dir,
|
|
},
|
|
{ .ctl_name = 0 }
|
|
};
|
|
|
|
static int __init init_mqueue_fs(void)
|
|
{
|
|
int error;
|
|
|
|
mqueue_inode_cachep = kmem_cache_create("mqueue_inode_cache",
|
|
sizeof(struct mqueue_inode_info), 0,
|
|
SLAB_HWCACHE_ALIGN, init_once);
|
|
if (mqueue_inode_cachep == NULL)
|
|
return -ENOMEM;
|
|
|
|
/* ignore failues - they are not fatal */
|
|
mq_sysctl_table = register_sysctl_table(mq_sysctl_root);
|
|
|
|
error = register_filesystem(&mqueue_fs_type);
|
|
if (error)
|
|
goto out_sysctl;
|
|
|
|
if (IS_ERR(mqueue_mnt = kern_mount(&mqueue_fs_type))) {
|
|
error = PTR_ERR(mqueue_mnt);
|
|
goto out_filesystem;
|
|
}
|
|
|
|
/* internal initialization - not common for vfs */
|
|
queues_count = 0;
|
|
spin_lock_init(&mq_lock);
|
|
|
|
return 0;
|
|
|
|
out_filesystem:
|
|
unregister_filesystem(&mqueue_fs_type);
|
|
out_sysctl:
|
|
if (mq_sysctl_table)
|
|
unregister_sysctl_table(mq_sysctl_table);
|
|
kmem_cache_destroy(mqueue_inode_cachep);
|
|
return error;
|
|
}
|
|
|
|
__initcall(init_mqueue_fs);
|