/* * POSIX message queues filesystem for Linux. * * Copyright (C) 2003,2004 Krzysztof Benedyczak (golbi@mat.uni.torun.pl) * Michal Wronski (michal.wronski@gmail.com) * * Spinlocks: Mohamed Abbas (abbas.mohamed@intel.com) * Lockless receive & send, fd based notify: * Manfred Spraul (manfred@colorfullife.com) * * Audit: George Wilson (ltcgcw@us.ibm.com) * * This file is released under the GPL. */ #include <linux/capability.h>#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/audit.h>#include <linux/signal.h>#include <linux/mutex.h>#include <linux/nsproxy.h>#include <linux/pid.h>#include <linux/ipc_namespace.h>#include <linux/slab.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 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; struct pid* 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 const struct inode_operations mqueue_dir_inode_operations;static const struct file_operations mqueue_file_operations;static const struct super_operations mqueue_super_ops;static void remove_notification(struct mqueue_inode_info *info); static struct kmem_cache *mqueue_inode_cachep; 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);} /* * This routine should be called with the mq_lock held. */static inline struct ipc_namespace *__get_ns_from_inode(struct inode *inode){ return get_ipc_ns(inode->i_sb->s_fs_info);} static struct ipc_namespace *get_ns_from_inode(struct inode *inode){ struct ipc_namespace *ns; spin_lock(&mq_lock); ns = __get_ns_from_inode(inode); spin_unlock(&mq_lock); return ns;} static struct inode *mqueue_get_inode(struct super_block *sb, struct ipc_namespace *ipc_ns, int mode, struct mq_attr *attr){ struct user_struct *u = current_user(); 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_mtime = inode->i_ctime = inode->i_atime = CURRENT_TIME; if (S_ISREG(mode)) { struct mqueue_inode_info *info; struct task_struct *p = current; 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->notify_owner = NULL; info->qsize = 0; info->user = NULL; /* set when all is ok */ memset(&info->attr, 0, sizeof(info->attr)); info->attr.mq_maxmsg = ipc_ns->mq_msg_max; info->attr.mq_msgsize = ipc_ns->mq_msgsize_max; 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 *); info->messages = kmalloc(mq_msg_tblsz, GFP_KERNEL); if (!info->messages) goto out_inode; 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 > task_rlimit(p, RLIMIT_MSGQUEUE)) { spin_unlock(&mq_lock); /* mqueue_delete_inode() releases info->messages */ goto out_inode; } u->mq_bytes += mq_bytes; spin_unlock(&mq_lock); /* all is ok */ info->user = get_uid(u); } else if (S_ISDIR(mode)) { inc_nlink(inode); /* 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; struct ipc_namespace *ns = data; int error; 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, ns, S_IFDIR | S_ISVTX | S_IRWXUGO, NULL); if (!inode) { error = -ENOMEM; goto out; } sb->s_root = d_alloc_root(inode); if (!sb->s_root) { iput(inode); error = -ENOMEM; goto out; } error = 0; out: return error;} static int mqueue_get_sb(struct file_system_type *fs_type, int flags, const char *dev_name, void *data, struct vfsmount *mnt){ if (!(flags & MS_KERNMOUNT)) data = current->nsproxy->ipc_ns; return get_sb_ns(fs_type, flags, data, mqueue_fill_super, mnt);} static void init_once(void *foo){ struct mqueue_inode_info *p = (struct mqueue_inode_info *) foo; 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, GFP_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; struct ipc_namespace *ipc_ns; if (S_ISDIR(inode->i_mode)) { clear_inode(inode); return; } ipc_ns = get_ns_from_inode(inode); 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); /* Total amount of bytes accounted for the mqueue */ mq_bytes = info->attr.mq_maxmsg * (sizeof(struct msg_msg *) + info->attr.mq_msgsize); user = info->user; if (user) { spin_lock(&mq_lock); user->mq_bytes -= mq_bytes; /* * get_ns_from_inode() ensures that the * (ipc_ns = sb->s_fs_info) is either a valid ipc_ns * to which we now hold a reference, or it is NULL. * We can't put it here under mq_lock, though. */ if (ipc_ns) ipc_ns->mq_queues_count--; spin_unlock(&mq_lock); free_uid(user); } if (ipc_ns) put_ipc_ns(ipc_ns);} 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; struct ipc_namespace *ipc_ns; spin_lock(&mq_lock); ipc_ns = __get_ns_from_inode(dir); if (!ipc_ns) { error = -EACCES; goto out_unlock; } if (ipc_ns->mq_queues_count >= ipc_ns->mq_queues_max && !capable(CAP_SYS_RESOURCE)) { error = -ENOSPC; goto out_unlock; } ipc_ns->mq_queues_count++; spin_unlock(&mq_lock); inode = mqueue_get_inode(dir->i_sb, ipc_ns, mode, attr); if (!inode) { error = -ENOMEM; spin_lock(&mq_lock); ipc_ns->mq_queues_count--; goto out_unlock; } put_ipc_ns(ipc_ns); 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_unlock: spin_unlock(&mq_lock); if (ipc_ns) put_ipc_ns(ipc_ns); 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; drop_nlink(inode); 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_path.dentry->d_inode); char buffer[FILENT_SIZE]; ssize_t ret; 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, pid_vnr(info->notify_owner)); spin_unlock(&info->lock); buffer[sizeof(buffer)-1] = '\0'; ret = simple_read_from_buffer(u_data, count, off, buffer, strlen(buffer)); if (ret <= 0) return ret; filp->f_path.dentry->d_inode->i_atime = filp->f_path.dentry->d_inode->i_ctime = CURRENT_TIME; return ret;} static int mqueue_flush_file(struct file *filp, fl_owner_t id){ struct mqueue_inode_info *info = MQUEUE_I(filp->f_path.dentry->d_inode); spin_lock(&info->lock); if (task_tgid(current) == 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_path.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;}Lines 1–500 of 1326. 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/* * POSIX message queues filesystem for Linux. * * Copyright (C) 2003,2004 Krzysztof Benedyczak (golbi@mat.uni.torun.pl) * Michal Wronski (michal.wronski@gmail.com) * * Spinlocks: Mohamed Abbas (abbas.mohamed@intel.com) * Lockless receive & send, fd based notify: * Manfred Spraul (manfred@colorfullife.com) * * Audit: George Wilson (ltcgcw@us.ibm.com) * * This file is released under the GPL. */ #include <linux/capability.h> #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/audit.h> #include <linux/signal.h> #include <linux/mutex.h> #include <linux/nsproxy.h> #include <linux/pid.h> #include <linux/ipc_namespace.h> #include <linux/slab.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 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; struct pid* 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 const struct inode_operations mqueue_dir_inode_operations; static const struct file_operations mqueue_file_operations; static const struct super_operations mqueue_super_ops; static void remove_notification(struct mqueue_inode_info *info); static struct kmem_cache *mqueue_inode_cachep; 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); } /* * This routine should be called with the mq_lock held. */ static inline struct ipc_namespace *__get_ns_from_inode(struct inode *inode) { return get_ipc_ns(inode->i_sb->s_fs_info); } static struct ipc_namespace *get_ns_from_inode(struct inode *inode) { struct ipc_namespace *ns; spin_lock(&mq_lock); ns = __get_ns_from_inode(inode); spin_unlock(&mq_lock); return ns; } static struct inode *mqueue_get_inode(struct super_block *sb, struct ipc_namespace *ipc_ns, int mode, struct mq_attr *attr) { struct user_struct *u = current_user(); 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_mtime = inode->i_ctime = inode->i_atime = CURRENT_TIME; if (S_ISREG(mode)) { struct mqueue_inode_info *info; struct task_struct *p = current; 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->notify_owner = NULL; info->qsize = 0; info->user = NULL; /* set when all is ok */ memset(&info->attr, 0, sizeof(info->attr)); info->attr.mq_maxmsg = ipc_ns->mq_msg_max; info->attr.mq_msgsize = ipc_ns->mq_msgsize_max; 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 *); info->messages = kmalloc(mq_msg_tblsz, GFP_KERNEL); if (!info->messages) goto out_inode; 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 > task_rlimit(p, RLIMIT_MSGQUEUE)) { spin_unlock(&mq_lock); /* mqueue_delete_inode() releases info->messages */ goto out_inode; } u->mq_bytes += mq_bytes; spin_unlock(&mq_lock); /* all is ok */ info->user = get_uid(u); } else if (S_ISDIR(mode)) { inc_nlink(inode); /* 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; struct ipc_namespace *ns = data; int error; 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, ns, S_IFDIR | S_ISVTX | S_IRWXUGO, NULL); if (!inode) { error = -ENOMEM; goto out; } sb->s_root = d_alloc_root(inode); if (!sb->s_root) { iput(inode); error = -ENOMEM; goto out; } error = 0; out: return error; } static int mqueue_get_sb(struct file_system_type *fs_type, int flags, const char *dev_name, void *data, struct vfsmount *mnt) { if (!(flags & MS_KERNMOUNT)) data = current->nsproxy->ipc_ns; return get_sb_ns(fs_type, flags, data, mqueue_fill_super, mnt); } static void init_once(void *foo) { struct mqueue_inode_info *p = (struct mqueue_inode_info *) foo; 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, GFP_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; struct ipc_namespace *ipc_ns; if (S_ISDIR(inode->i_mode)) { clear_inode(inode); return; } ipc_ns = get_ns_from_inode(inode); 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); /* Total amount of bytes accounted for the mqueue */ mq_bytes = info->attr.mq_maxmsg * (sizeof(struct msg_msg *) + info->attr.mq_msgsize); user = info->user; if (user) { spin_lock(&mq_lock); user->mq_bytes -= mq_bytes; /* * get_ns_from_inode() ensures that the * (ipc_ns = sb->s_fs_info) is either a valid ipc_ns * to which we now hold a reference, or it is NULL. * We can't put it here under mq_lock, though. */ if (ipc_ns) ipc_ns->mq_queues_count--; spin_unlock(&mq_lock); free_uid(user); } if (ipc_ns) put_ipc_ns(ipc_ns); } 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; struct ipc_namespace *ipc_ns; spin_lock(&mq_lock); ipc_ns = __get_ns_from_inode(dir); if (!ipc_ns) { error = -EACCES; goto out_unlock; } if (ipc_ns->mq_queues_count >= ipc_ns->mq_queues_max && !capable(CAP_SYS_RESOURCE)) { error = -ENOSPC; goto out_unlock; } ipc_ns->mq_queues_count++; spin_unlock(&mq_lock); inode = mqueue_get_inode(dir->i_sb, ipc_ns, mode, attr); if (!inode) { error = -ENOMEM; spin_lock(&mq_lock); ipc_ns->mq_queues_count--; goto out_unlock; } put_ipc_ns(ipc_ns); 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_unlock: spin_unlock(&mq_lock); if (ipc_ns) put_ipc_ns(ipc_ns); 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; drop_nlink(inode); 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_path.dentry->d_inode); char buffer[FILENT_SIZE]; ssize_t ret; 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, pid_vnr(info->notify_owner)); spin_unlock(&info->lock); buffer[sizeof(buffer)-1] = '\0'; ret = simple_read_from_buffer(u_data, count, off, buffer, strlen(buffer)); if (ret <= 0) return ret; filp->f_path.dentry->d_inode->i_atime = filp->f_path.dentry->d_inode->i_ctime = CURRENT_TIME; return ret; } static int mqueue_flush_file(struct file *filp, fl_owner_t id) { struct mqueue_inode_info *info = MQUEUE_I(filp->f_path.dentry->d_inode); spin_lock(&info->lock); if (task_tgid(current) == 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_path.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; }