| /* |
| * POSIX message queues filesystem for Linux. |
| * |
| * Copyright (C) 2003,2004 Krzysztof Benedyczak (golbi@mat.uni.torun.pl) |
| * Michal Wronski (Michal.Wronski@motorola.com) |
| * |
| * Spinlocks: Mohamed Abbas (abbas.mohamed@intel.com) |
| * Lockless receive & send, fd based notify: |
| * Manfred Spraul (manfred@colorfullife.com) |
| * |
| * This file is released under the GPL. |
| */ |
| |
| #include <linux/init.h> |
| #include <linux/pagemap.h> |
| #include <linux/file.h> |
| #include <linux/mount.h> |
| #include <linux/namei.h> |
| #include <linux/sysctl.h> |
| #include <linux/poll.h> |
| #include <linux/mqueue.h> |
| #include <linux/msg.h> |
| #include <linux/skbuff.h> |
| #include <linux/netlink.h> |
| #include <linux/syscalls.h> |
| #include <linux/signal.h> |
| #include <net/sock.h> |
| #include "util.h" |
| |
| #define MQUEUE_MAGIC 0x19800202 |
| #define DIRENT_SIZE 20 |
| #define FILENT_SIZE 80 |
| |
| #define SEND 0 |
| #define RECV 1 |
| |
| #define STATE_NONE 0 |
| #define STATE_PENDING 1 |
| #define STATE_READY 2 |
| |
| /* used by sysctl */ |
| #define FS_MQUEUE 1 |
| #define CTL_QUEUESMAX 2 |
| #define CTL_MSGMAX 3 |
| #define CTL_MSGSIZEMAX 4 |
| |
| /* default values */ |
| #define DFLT_QUEUESMAX 256 /* max number of message queues */ |
| #define DFLT_MSGMAX 10 /* max number of messages in each queue */ |
| #define HARD_MSGMAX (131072/sizeof(void*)) |
| #define DFLT_MSGSIZEMAX 8192 /* max message size */ |
| |
| #define NOTIFY_COOKIE_LEN 32 |
| |
| struct ext_wait_queue { /* queue of sleeping tasks */ |
| struct task_struct *task; |
| struct list_head list; |
| struct msg_msg *msg; /* ptr of loaded message */ |
| int state; /* one of STATE_* values */ |
| }; |
| |
| struct mqueue_inode_info { |
| spinlock_t lock; |
| struct inode vfs_inode; |
| wait_queue_head_t wait_q; |
| |
| struct msg_msg **messages; |
| struct mq_attr attr; |
| |
| struct sigevent notify; |
| pid_t notify_owner; |
| struct user_struct *user; /* user who created, for accounting */ |
| struct sock *notify_sock; |
| struct sk_buff *notify_cookie; |
| |
| /* for tasks waiting for free space and messages, respectively */ |
| struct ext_wait_queue e_wait_q[2]; |
| |
| unsigned long qsize; /* size of queue in memory (sum of all msgs) */ |
| }; |
| |
| static struct inode_operations mqueue_dir_inode_operations; |
| static struct file_operations mqueue_file_operations; |
| static struct super_operations mqueue_super_ops; |
| static void remove_notification(struct mqueue_inode_info *info); |
| |
| static spinlock_t mq_lock; |
| static kmem_cache_t *mqueue_inode_cachep; |
| static struct vfsmount *mqueue_mnt; |
| |
| static unsigned int queues_count; |
| static unsigned int queues_max = DFLT_QUEUESMAX; |
| static unsigned int msg_max = DFLT_MSGMAX; |
| static unsigned int msgsize_max = DFLT_MSGSIZEMAX; |
| |
| static struct ctl_table_header * mq_sysctl_table; |
| |
| static inline struct mqueue_inode_info *MQUEUE_I(struct inode *inode) |
| { |
| return container_of(inode, struct mqueue_inode_info, vfs_inode); |
| } |
| |
| static struct inode *mqueue_get_inode(struct super_block *sb, int mode, |
| struct mq_attr *attr) |
| { |
| struct inode *inode; |
| |
| inode = new_inode(sb); |
| if (inode) { |
| inode->i_mode = mode; |
| inode->i_uid = current->fsuid; |
| inode->i_gid = current->fsgid; |
| inode->i_blksize = PAGE_CACHE_SIZE; |
| inode->i_blocks = 0; |
| inode->i_mtime = inode->i_ctime = inode->i_atime = |
| CURRENT_TIME; |
| |
| if (S_ISREG(mode)) { |
| struct mqueue_inode_info *info; |
| struct task_struct *p = current; |
| struct user_struct *u = p->user; |
| unsigned long mq_bytes, mq_msg_tblsz; |
| |
| inode->i_fop = &mqueue_file_operations; |
| inode->i_size = FILENT_SIZE; |
| /* mqueue specific info */ |
| info = MQUEUE_I(inode); |
| spin_lock_init(&info->lock); |
| init_waitqueue_head(&info->wait_q); |
| INIT_LIST_HEAD(&info->e_wait_q[0].list); |
| INIT_LIST_HEAD(&info->e_wait_q[1].list); |
| info->messages = NULL; |
| info->notify_owner = 0; |
| info->qsize = 0; |
| info->user = NULL; /* set when all is ok */ |
| memset(&info->attr, 0, sizeof(info->attr)); |
| info->attr.mq_maxmsg = DFLT_MSGMAX; |
| info->attr.mq_msgsize = DFLT_MSGSIZEMAX; |
| if (attr) { |
| info->attr.mq_maxmsg = attr->mq_maxmsg; |
| info->attr.mq_msgsize = attr->mq_msgsize; |
| } |
| mq_msg_tblsz = info->attr.mq_maxmsg * sizeof(struct msg_msg *); |
| mq_bytes = (mq_msg_tblsz + |
| (info->attr.mq_maxmsg * info->attr.mq_msgsize)); |
| |
| spin_lock(&mq_lock); |
| if (u->mq_bytes + mq_bytes < u->mq_bytes || |
| u->mq_bytes + mq_bytes > |
| p->signal->rlim[RLIMIT_MSGQUEUE].rlim_cur) { |
| spin_unlock(&mq_lock); |
| goto out_inode; |
| } |
| u->mq_bytes += mq_bytes; |
| spin_unlock(&mq_lock); |
| |
| info->messages = kmalloc(mq_msg_tblsz, GFP_KERNEL); |
| if (!info->messages) { |
| spin_lock(&mq_lock); |
| u->mq_bytes -= mq_bytes; |
| spin_unlock(&mq_lock); |
| goto out_inode; |
| } |
| /* all is ok */ |
| info->user = get_uid(u); |
| } else if (S_ISDIR(mode)) { |
| inode->i_nlink++; |
| /* Some things misbehave if size == 0 on a directory */ |
| inode->i_size = 2 * DIRENT_SIZE; |
| inode->i_op = &mqueue_dir_inode_operations; |
| inode->i_fop = &simple_dir_operations; |
| } |
| } |
| return inode; |
| out_inode: |
| make_bad_inode(inode); |
| iput(inode); |
| return NULL; |
| } |
| |
| static int mqueue_fill_super(struct super_block *sb, void *data, int silent) |
| { |
| struct inode *inode; |
| |
| sb->s_blocksize = PAGE_CACHE_SIZE; |
| sb->s_blocksize_bits = PAGE_CACHE_SHIFT; |
| sb->s_magic = MQUEUE_MAGIC; |
| sb->s_op = &mqueue_super_ops; |
| |
| inode = mqueue_get_inode(sb, S_IFDIR | S_ISVTX | S_IRWXUGO, NULL); |
| if (!inode) |
| return -ENOMEM; |
| |
| sb->s_root = d_alloc_root(inode); |
| if (!sb->s_root) { |
| iput(inode); |
| return -ENOMEM; |
| } |
| |
| return 0; |
| } |
| |
| static struct super_block *mqueue_get_sb(struct file_system_type *fs_type, |
| int flags, const char *dev_name, |
| void *data) |
| { |
| return get_sb_single(fs_type, flags, data, mqueue_fill_super); |
| } |
| |
| static void init_once(void *foo, kmem_cache_t * cachep, unsigned long flags) |
| { |
| struct mqueue_inode_info *p = (struct mqueue_inode_info *) foo; |
| |
| if ((flags & (SLAB_CTOR_VERIFY | SLAB_CTOR_CONSTRUCTOR)) == |
| SLAB_CTOR_CONSTRUCTOR) |
| inode_init_once(&p->vfs_inode); |
| } |
| |
| static struct inode *mqueue_alloc_inode(struct super_block *sb) |
| { |
| struct mqueue_inode_info *ei; |
| |
| ei = kmem_cache_alloc(mqueue_inode_cachep, SLAB_KERNEL); |
| if (!ei) |
| return NULL; |
| return &ei->vfs_inode; |
| } |
| |
| static void mqueue_destroy_inode(struct inode *inode) |
| { |
| kmem_cache_free(mqueue_inode_cachep, MQUEUE_I(inode)); |
| } |
| |
| static void mqueue_delete_inode(struct inode *inode) |
| { |
| struct mqueue_inode_info *info; |
| struct user_struct *user; |
| unsigned long mq_bytes; |
| int i; |
| |
| if (S_ISDIR(inode->i_mode)) { |
| clear_inode(inode); |
| return; |
| } |
| info = MQUEUE_I(inode); |
| spin_lock(&info->lock); |
| for (i = 0; i < info->attr.mq_curmsgs; i++) |
| free_msg(info->messages[i]); |
| kfree(info->messages); |
| spin_unlock(&info->lock); |
| |
| clear_inode(inode); |
| |
| mq_bytes = (info->attr.mq_maxmsg * sizeof(struct msg_msg *) + |
| (info->attr.mq_maxmsg * info->attr.mq_msgsize)); |
| user = info->user; |
| if (user) { |
| spin_lock(&mq_lock); |
| user->mq_bytes -= mq_bytes; |
| queues_count--; |
| spin_unlock(&mq_lock); |
| free_uid(user); |
| } |
| } |
| |
| static int mqueue_create(struct inode *dir, struct dentry *dentry, |
| int mode, struct nameidata *nd) |
| { |
| struct inode *inode; |
| struct mq_attr *attr = dentry->d_fsdata; |
| int error; |
| |
| spin_lock(&mq_lock); |
| if (queues_count >= queues_max && !capable(CAP_SYS_RESOURCE)) { |
| error = -ENOSPC; |
| goto out_lock; |
| } |
| queues_count++; |
| spin_unlock(&mq_lock); |
| |
| inode = mqueue_get_inode(dir->i_sb, mode, attr); |
| if (!inode) { |
| error = -ENOMEM; |
| spin_lock(&mq_lock); |
| queues_count--; |
| goto out_lock; |
| } |
| |
| dir->i_size += DIRENT_SIZE; |
| dir->i_ctime = dir->i_mtime = dir->i_atime = CURRENT_TIME; |
| |
| d_instantiate(dentry, inode); |
| dget(dentry); |
| return 0; |
| out_lock: |
| spin_unlock(&mq_lock); |
| return error; |
| } |
| |
| static int mqueue_unlink(struct inode *dir, struct dentry *dentry) |
| { |
| struct inode *inode = dentry->d_inode; |
| |
| dir->i_ctime = dir->i_mtime = dir->i_atime = CURRENT_TIME; |
| dir->i_size -= DIRENT_SIZE; |
| inode->i_nlink--; |
| dput(dentry); |
| return 0; |
| } |
| |
| /* |
| * This is routine for system read from queue file. |
| * To avoid mess with doing here some sort of mq_receive we allow |
| * to read only queue size & notification info (the only values |
| * that are interesting from user point of view and aren't accessible |
| * through std routines) |
| */ |
| static ssize_t mqueue_read_file(struct file *filp, char __user *u_data, |
| size_t count, loff_t * off) |
| { |
| struct mqueue_inode_info *info = MQUEUE_I(filp->f_dentry->d_inode); |
| char buffer[FILENT_SIZE]; |
| size_t slen; |
| loff_t o; |
| |
| if (!count) |
| return 0; |
| |
| spin_lock(&info->lock); |
| snprintf(buffer, sizeof(buffer), |
| "QSIZE:%-10lu NOTIFY:%-5d SIGNO:%-5d NOTIFY_PID:%-6d\n", |
| info->qsize, |
| info->notify_owner ? info->notify.sigev_notify : 0, |
| (info->notify_owner && |
| info->notify.sigev_notify == SIGEV_SIGNAL) ? |
| info->notify.sigev_signo : 0, |
| info->notify_owner); |
| spin_unlock(&info->lock); |
| buffer[sizeof(buffer)-1] = '\0'; |
| slen = strlen(buffer)+1; |
| |
| o = *off; |
| if (o > slen) |
| return 0; |
| |
| if (o + count > slen) |
| count = slen - o; |
| |
| if (copy_to_user(u_data, buffer + o, count)) |
| return -EFAULT; |
| |
| *off = o + count; |
| filp->f_dentry->d_inode->i_atime = filp->f_dentry->d_inode->i_ctime = CURRENT_TIME; |
| return count; |
| } |
| |
| static int mqueue_flush_file(struct file *filp) |
| { |
| struct mqueue_inode_info *info = MQUEUE_I(filp->f_dentry->d_inode); |
| |
| spin_lock(&info->lock); |
| if (current->tgid == info->notify_owner) |
| remove_notification(info); |
| |
| spin_unlock(&info->lock); |
| return 0; |
| } |
| |
| static unsigned int mqueue_poll_file(struct file *filp, struct poll_table_struct *poll_tab) |
| { |
| struct mqueue_inode_info *info = MQUEUE_I(filp->f_dentry->d_inode); |
| int retval = 0; |
| |
| poll_wait(filp, &info->wait_q, poll_tab); |
| |
| spin_lock(&info->lock); |
| if (info->attr.mq_curmsgs) |
| retval = POLLIN | POLLRDNORM; |
| |
| if (info->attr.mq_curmsgs < info->attr.mq_maxmsg) |
| retval |= POLLOUT | POLLWRNORM; |
| spin_unlock(&info->lock); |
| |
| return retval; |
| } |
| |
| /* Adds current to info->e_wait_q[sr] before element with smaller prio */ |
| static void wq_add(struct mqueue_inode_info *info, int sr, |
| struct ext_wait_queue *ewp) |
| { |
| struct ext_wait_queue *walk; |
| |
| ewp->task = current; |
| |
| list_for_each_entry(walk, &info->e_wait_q[sr].list, list) { |
| if (walk->task->static_prio <= current->static_prio) { |
| list_add_tail(&ewp->list, &walk->list); |
| return; |
| } |
| } |
| list_add_tail(&ewp->list, &info->e_wait_q[sr].list); |
| } |
| |
| /* |
| * Puts current task to sleep. Caller must hold queue lock. After return |
| * lock isn't held. |
| * sr: SEND or RECV |
| */ |
| static int wq_sleep(struct mqueue_inode_info *info, int sr, |
| long timeout, struct ext_wait_queue *ewp) |
| { |
| int retval; |
| signed long time; |
| |
| wq_add(info, sr, ewp); |
| |
| for (;;) { |
| set_current_state(TASK_INTERRUPTIBLE); |
| |
| spin_unlock(&info->lock); |
| time = schedule_timeout(timeout); |
| |
| while (ewp->state == STATE_PENDING) |
| cpu_relax(); |
| |
| if (ewp->state == STATE_READY) { |
| retval = 0; |
| goto out; |
| } |
| spin_lock(&info->lock); |
| if (ewp->state == STATE_READY) { |
| retval = 0; |
| goto out_unlock; |
| } |
| if (signal_pending(current)) { |
| retval = -ERESTARTSYS; |
| break; |
| } |
| if (time == 0) { |
| retval = -ETIMEDOUT; |
| break; |
| } |
| } |
| list_del(&ewp->list); |
| out_unlock: |
| spin_unlock(&info->lock); |
| out: |
| return retval; |
| } |
| |
| /* |
| * Returns waiting task that should be serviced first or NULL if none exists |
| */ |
| static struct ext_wait_queue *wq_get_first_waiter( |
| struct mqueue_inode_info *info, int sr) |
| { |
| struct list_head *ptr; |
| |
| ptr = info->e_wait_q[sr].list.prev; |
| if (ptr == &info->e_wait_q[sr].list) |
| return NULL; |
| return list_entry(ptr, struct ext_wait_queue, list); |
| } |
| |
| /* Auxiliary functions to manipulate messages' list */ |
| static void msg_insert(struct msg_msg *ptr, struct mqueue_inode_info *info) |
| { |
| int k; |
| |
| k = info->attr.mq_curmsgs - 1; |
| while (k >= 0 && info->messages[k]->m_type >= ptr->m_type) { |
| info->messages[k + 1] = info->messages[k]; |
| k--; |
| } |
| info->attr.mq_curmsgs++; |
| info->qsize += ptr->m_ts; |
| info->messages[k + 1] = ptr; |
| } |
| |
| static inline struct msg_msg *msg_get(struct mqueue_inode_info *info) |
| { |
| info->qsize -= info->messages[--info->attr.mq_curmsgs]->m_ts; |
| return info->messages[info->attr.mq_curmsgs]; |
| } |
| |
| static inline void set_cookie(struct sk_buff *skb, char code) |
| { |
| ((char*)skb->data)[NOTIFY_COOKIE_LEN-1] = code; |
| } |
| |
| /* |
| * 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 && |
| info->attr.mq_curmsgs == 1) { |
| struct siginfo sig_i; |
| switch (info->notify.sigev_notify) { |
| case SIGEV_NONE: |
| 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_proc_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, 0); |
| break; |
| } |
| /* after notification unregisters process */ |
| info->notify_owner = 0; |
| } |
| 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 != 0 && |
| info->notify.sigev_notify == SIGEV_THREAD) { |
| set_cookie(info->notify_cookie, NOTIFY_REMOVED); |
| netlink_sendskb(info->notify_sock, info->notify_cookie, 0); |
| } |
| info->notify_owner = 0; |
| } |
| |
| 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; |
| |
| if (IS_ERR(name = getname(u_name))) |
| return PTR_ERR(name); |
| |
| fd = get_unused_fd(); |
| if (fd < 0) |
| goto out_putname; |
| |
| down(&mqueue_mnt->mnt_root->d_inode->i_sem); |
| 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 */ |
| 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; |
| 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: |
| up(&mqueue_mnt->mnt_root->d_inode->i_sem); |
| 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); |
| |
| down(&mqueue_mnt->mnt_root->d_inode->i_sem); |
| 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: |
| up(&mqueue_mnt->mnt_root->d_inode->i_sem); |
| 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 fore 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; |
| |
| 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_dentry->d_inode; |
| if (unlikely(filp->f_op != &mqueue_file_operations)) |
| goto out_fput; |
| info = MQUEUE_I(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; |
| |
| timeout = prepare_timeout(u_abs_timeout); |
| |
| ret = -EBADF; |
| filp = fget(mqdes); |
| if (unlikely(!filp)) |
| goto out; |
| |
| inode = filp->f_dentry->d_inode; |
| if (unlikely(filp->f_op != &mqueue_file_operations)) |
| goto out_fput; |
| info = MQUEUE_I(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; |
| |
| 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_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 == current->tgid) { |
| remove_notification(info); |
| inode->i_atime = inode->i_ctime = CURRENT_TIME; |
| } |
| } else if (info->notify_owner != 0) { |
| 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 = current->tgid; |
| 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_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) { |
| 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 struct inode_operations mqueue_dir_inode_operations = { |
| .lookup = simple_lookup, |
| .create = mqueue_create, |
| .unlink = mqueue_unlink, |
| }; |
| |
| static 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, NULL); |
| if (mqueue_inode_cachep == NULL) |
| return -ENOMEM; |
| |
| /* ignore failues - they are not fatal */ |
| mq_sysctl_table = register_sysctl_table(mq_sysctl_root, 0); |
| |
| 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); |
| if (kmem_cache_destroy(mqueue_inode_cachep)) { |
| printk(KERN_INFO |
| "mqueue_inode_cache: not all structures were freed\n"); |
| } |
| return error; |
| } |
| |
| __initcall(init_mqueue_fs); |