diff options
Diffstat (limited to 'ipc/mqueue.c')
| -rw-r--r-- | ipc/mqueue.c | 1252 |
1 files changed, 1252 insertions, 0 deletions
diff --git a/ipc/mqueue.c b/ipc/mqueue.c new file mode 100644 index 0000000..cb0cd3c --- /dev/null +++ b/ipc/mqueue.c @@ -0,0 +1,1252 @@ +/* + * POSIX message queues filesystem for Linux. + * + * Copyright (C) 2003,2004 Krzysztof Benedyczak (golbi@mat.uni.torun.pl) + * Michal Wronski (wrona@mat.uni.torun.pl) + * + * 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 <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 accouting */ + 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 file *filp; + struct mq_attr attr; + int ret; + + if (u_attr != NULL) { + if (copy_from_user(&attr, u_attr, sizeof(attr))) + return ERR_PTR(-EFAULT); + if (!mq_attr_ok(&attr)) + return ERR_PTR(-EINVAL); + /* store for use during create */ + dentry->d_fsdata = &attr; + } + + ret = vfs_create(dir->d_inode, dentry, mode, NULL); + dentry->d_fsdata = NULL; + if (ret) + return ERR_PTR(ret); + + filp = dentry_open(dentry, mqueue_mnt, oflag); + if (!IS_ERR(filp)) + dget(dentry); + + return filp; +} + +/* 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 }; + struct file *filp; + + if ((oflag & O_ACCMODE) == (O_RDWR | O_WRONLY)) + return ERR_PTR(-EINVAL); + + if (permission(dentry->d_inode, oflag2acc[oflag & O_ACCMODE], NULL)) + return ERR_PTR(-EACCES); + + filp = dentry_open(dentry, mqueue_mnt, oflag); + + if (!IS_ERR(filp)) + dget(dentry); + + return filp; +} + +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 */ + filp = (oflag & O_EXCL) ? ERR_PTR(-EEXIST) : + do_open(dentry, oflag); + } else { + filp = do_create(mqueue_mnt->mnt_root, dentry, + oflag, mode, u_attr); + } + } else + filp = (dentry->d_inode) ? do_open(dentry, oflag) : + ERR_PTR(-ENOENT); + + dput(dentry); + + 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_putfd: + mntput(mqueue_mnt); + 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); + 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); + 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 && + (notification.sigev_signo < 0 || + notification.sigev_signo > _NSIG)) { + 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); + 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); |
