/* * Server-side file descriptor management * * Copyright (C) 2000, 2003 Alexandre Julliard * * This library is free software; you can redistribute it and/or * modify it under the terms of the GNU Lesser General Public * License as published by the Free Software Foundation; either * version 2.1 of the License, or (at your option) any later version. * * This library is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * Lesser General Public License for more details. * * You should have received a copy of the GNU Lesser General Public * License along with this library; if not, write to the Free Software * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */ #include "config.h" #include #include #include #include #include #include #include #include #include #ifdef HAVE_POLL_H #include #endif #ifdef HAVE_SYS_POLL_H #include #endif #ifdef HAVE_STDINT_H #include #endif #include #include #include #include #include "object.h" #include "file.h" #include "handle.h" #include "process.h" #include "request.h" #include "winbase.h" #include "winreg.h" #include "winternl.h" #if defined(HAVE_SYS_EPOLL_H) && defined(HAVE_EPOLL_CREATE) # include # define USE_EPOLL #elif defined(linux) && defined(__i386__) && defined(HAVE_STDINT_H) # define USE_EPOLL # define EPOLLIN POLLIN # define EPOLLOUT POLLOUT # define EPOLLERR POLLERR # define EPOLLHUP POLLHUP # define EPOLL_CTL_ADD 1 # define EPOLL_CTL_DEL 2 # define EPOLL_CTL_MOD 3 typedef union epoll_data { void *ptr; int fd; uint32_t u32; uint64_t u64; } epoll_data_t; struct epoll_event { uint32_t events; epoll_data_t data; }; #define SYSCALL_RET(ret) do { \ if (ret < 0) { errno = -ret; ret = -1; } \ return ret; \ } while(0) static inline int epoll_create( int size ) { int ret; __asm__( "pushl %%ebx; movl %2,%%ebx; int $0x80; popl %%ebx" : "=a" (ret) : "0" (254 /*NR_epoll_create*/), "r" (size) ); SYSCALL_RET(ret); } static inline int epoll_ctl( int epfd, int op, int fd, const struct epoll_event *event ) { int ret; __asm__( "pushl %%ebx; movl %2,%%ebx; int $0x80; popl %%ebx" : "=a" (ret) : "0" (255 /*NR_epoll_ctl*/), "r" (epfd), "c" (op), "d" (fd), "S" (event), "m" (*event) ); SYSCALL_RET(ret); } static inline int epoll_wait( int epfd, struct epoll_event *events, int maxevents, int timeout ) { int ret; __asm__( "pushl %%ebx; movl %2,%%ebx; int $0x80; popl %%ebx" : "=a" (ret) : "0" (256 /*NR_epoll_wait*/), "r" (epfd), "c" (events), "d" (maxevents), "S" (timeout) : "memory" ); SYSCALL_RET(ret); } #undef SYSCALL_RET #endif /* linux && __i386__ && HAVE_STDINT_H */ /* Because of the stupid Posix locking semantics, we need to keep * track of all file descriptors referencing a given file, and not * close a single one until all the locks are gone (sigh). */ /* file descriptor object */ /* closed_fd is used to keep track of the unix fd belonging to a closed fd object */ struct closed_fd { struct list entry; /* entry in inode closed list */ int fd; /* the unix file descriptor */ char unlink[1]; /* name to unlink on close (if any) */ }; struct fd { struct object obj; /* object header */ const struct fd_ops *fd_ops; /* file descriptor operations */ struct inode *inode; /* inode that this fd belongs to */ struct list inode_entry; /* entry in inode fd list */ struct closed_fd *closed; /* structure to store the unix fd at destroy time */ struct object *user; /* object using this file descriptor */ struct list locks; /* list of locks on this fd */ unsigned int access; /* file access (GENERIC_READ/WRITE) */ unsigned int sharing; /* file sharing mode */ int unix_fd; /* unix file descriptor */ int fs_locks; /* can we use filesystem locks for this fd? */ int poll_index; /* index of fd in poll array */ struct list read_q; /* async readers of this fd */ struct list write_q; /* async writers of this fd */ }; static void fd_dump( struct object *obj, int verbose ); static void fd_destroy( struct object *obj ); static const struct object_ops fd_ops = { sizeof(struct fd), /* size */ fd_dump, /* dump */ no_add_queue, /* add_queue */ NULL, /* remove_queue */ NULL, /* signaled */ NULL, /* satisfied */ no_signal, /* signal */ no_get_fd, /* get_fd */ no_close_handle, /* close_handle */ fd_destroy /* destroy */ }; /* inode object */ struct inode { struct object obj; /* object header */ struct list entry; /* inode hash list entry */ unsigned int hash; /* hashing code */ dev_t dev; /* device number */ ino_t ino; /* inode number */ struct list open; /* list of open file descriptors */ struct list locks; /* list of file locks */ struct list closed; /* list of file descriptors to close at destroy time */ }; static void inode_dump( struct object *obj, int verbose ); static void inode_destroy( struct object *obj ); static const struct object_ops inode_ops = { sizeof(struct inode), /* size */ inode_dump, /* dump */ no_add_queue, /* add_queue */ NULL, /* remove_queue */ NULL, /* signaled */ NULL, /* satisfied */ no_signal, /* signal */ no_get_fd, /* get_fd */ no_close_handle, /* close_handle */ inode_destroy /* destroy */ }; /* file lock object */ struct file_lock { struct object obj; /* object header */ struct fd *fd; /* fd owning this lock */ struct list fd_entry; /* entry in list of locks on a given fd */ struct list inode_entry; /* entry in inode list of locks */ int shared; /* shared lock? */ file_pos_t start; /* locked region is interval [start;end) */ file_pos_t end; struct process *process; /* process owning this lock */ struct list proc_entry; /* entry in list of locks owned by the process */ }; static void file_lock_dump( struct object *obj, int verbose ); static int file_lock_signaled( struct object *obj, struct thread *thread ); static const struct object_ops file_lock_ops = { sizeof(struct file_lock), /* size */ file_lock_dump, /* dump */ add_queue, /* add_queue */ remove_queue, /* remove_queue */ file_lock_signaled, /* signaled */ no_satisfied, /* satisfied */ no_signal, /* signal */ no_get_fd, /* get_fd */ no_close_handle, /* close_handle */ no_destroy /* destroy */ }; #define OFF_T_MAX (~((file_pos_t)1 << (8*sizeof(off_t)-1))) #define FILE_POS_T_MAX (~(file_pos_t)0) static file_pos_t max_unix_offset = OFF_T_MAX; #define DUMP_LONG_LONG(val) do { \ if (sizeof(val) > sizeof(unsigned long) && (val) > ~0UL) \ fprintf( stderr, "%lx%08lx", (unsigned long)((val) >> 32), (unsigned long)(val) ); \ else \ fprintf( stderr, "%lx", (unsigned long)(val) ); \ } while (0) /****************************************************************/ /* timeouts support */ struct timeout_user { struct list entry; /* entry in sorted timeout list */ struct timeval when; /* timeout expiry (absolute time) */ timeout_callback callback; /* callback function */ void *private; /* callback private data */ }; static struct list timeout_list = LIST_INIT(timeout_list); /* sorted timeouts list */ /* add a timeout user */ struct timeout_user *add_timeout_user( const struct timeval *when, timeout_callback func, void *private ) { struct timeout_user *user; struct list *ptr; if (!(user = mem_alloc( sizeof(*user) ))) return NULL; user->when = *when; user->callback = func; user->private = private; /* Now insert it in the linked list */ LIST_FOR_EACH( ptr, &timeout_list ) { struct timeout_user *timeout = LIST_ENTRY( ptr, struct timeout_user, entry ); if (!time_before( &timeout->when, when )) break; } list_add_before( ptr, &user->entry ); return user; } /* remove a timeout user */ void remove_timeout_user( struct timeout_user *user ) { list_remove( &user->entry ); free( user ); } /* add a timeout in milliseconds to an absolute time */ void add_timeout( struct timeval *when, int timeout ) { if (timeout) { long sec = timeout / 1000; if ((when->tv_usec += (timeout - 1000*sec) * 1000) >= 1000000) { when->tv_usec -= 1000000; when->tv_sec++; } when->tv_sec += sec; } } /****************************************************************/ /* poll support */ static struct fd **poll_users; /* users array */ static struct pollfd *pollfd; /* poll fd array */ static int nb_users; /* count of array entries actually in use */ static int active_users; /* current number of active users */ static int allocated_users; /* count of allocated entries in the array */ static struct fd **freelist; /* list of free entries in the array */ #ifdef USE_EPOLL static int epoll_fd; static struct epoll_event *epoll_events; /* set the events that epoll waits for on this fd; helper for set_fd_events */ static inline void set_fd_epoll_events( struct fd *fd, int user, int events ) { struct epoll_event ev; int ctl; if (epoll_fd == -1) return; if (events == -1) /* stop waiting on this fd completely */ { if (pollfd[user].fd == -1) return; /* already removed */ ctl = EPOLL_CTL_DEL; } else if (pollfd[user].fd == -1) { if (pollfd[user].events) return; /* stopped waiting on it, don't restart */ ctl = EPOLL_CTL_ADD; } else { if (pollfd[user].events == events) return; /* nothing to do */ ctl = EPOLL_CTL_MOD; } ev.events = events; ev.data.u32 = user; if (epoll_ctl( epoll_fd, ctl, fd->unix_fd, &ev ) == -1) { if (errno == ENOMEM) /* not enough memory, give up on epoll */ { close( epoll_fd ); epoll_fd = -1; } else perror( "epoll_ctl" ); /* should not happen */ } } #else /* USE_EPOLL */ static inline void set_fd_epoll_events( struct fd *fd, int user, int events ) { } #endif /* USE_EPOLL */ /* add a user in the poll array and return its index, or -1 on failure */ static int add_poll_user( struct fd *fd ) { int ret; if (freelist) { ret = freelist - poll_users; freelist = (struct fd **)poll_users[ret]; } else { if (nb_users == allocated_users) { struct fd **newusers; struct pollfd *newpoll; int new_count = allocated_users ? (allocated_users + allocated_users / 2) : 16; if (!(newusers = realloc( poll_users, new_count * sizeof(*poll_users) ))) return -1; if (!(newpoll = realloc( pollfd, new_count * sizeof(*pollfd) ))) { if (allocated_users) poll_users = newusers; else free( newusers ); return -1; } poll_users = newusers; pollfd = newpoll; #ifdef USE_EPOLL if (!allocated_users) epoll_fd = epoll_create( new_count ); if (epoll_fd != -1) { struct epoll_event *new_events; if (!(new_events = realloc( epoll_events, new_count * sizeof(*epoll_events) ))) return -1; epoll_events = new_events; } #endif allocated_users = new_count; } ret = nb_users++; } pollfd[ret].fd = -1; pollfd[ret].events = 0; pollfd[ret].revents = 0; poll_users[ret] = fd; active_users++; return ret; } /* remove a user from the poll list */ static void remove_poll_user( struct fd *fd, int user ) { assert( user >= 0 ); assert( poll_users[user] == fd ); #ifdef USE_EPOLL if (epoll_fd != -1 && pollfd[user].fd != -1) { struct epoll_event dummy; epoll_ctl( epoll_fd, EPOLL_CTL_DEL, fd->unix_fd, &dummy ); } #endif pollfd[user].fd = -1; pollfd[user].events = 0; pollfd[user].revents = 0; poll_users[user] = (struct fd *)freelist; freelist = &poll_users[user]; active_users--; } /* process pending timeouts and return the time until the next timeout, in milliseconds */ static int get_next_timeout(void) { if (!list_empty( &timeout_list )) { struct list expired_list, *ptr; struct timeval now; gettimeofday( &now, NULL ); /* first remove all expired timers from the list */ list_init( &expired_list ); while ((ptr = list_head( &timeout_list )) != NULL) { struct timeout_user *timeout = LIST_ENTRY( ptr, struct timeout_user, entry ); if (!time_before( &now, &timeout->when )) { list_remove( &timeout->entry ); list_add_tail( &expired_list, &timeout->entry ); } else break; } /* now call the callback for all the removed timers */ while ((ptr = list_head( &expired_list )) != NULL) { struct timeout_user *timeout = LIST_ENTRY( ptr, struct timeout_user, entry ); list_remove( &timeout->entry ); timeout->callback( timeout->private ); free( timeout ); } if ((ptr = list_head( &timeout_list )) != NULL) { struct timeout_user *timeout = LIST_ENTRY( ptr, struct timeout_user, entry ); int diff = (timeout->when.tv_sec - now.tv_sec) * 1000 + (timeout->when.tv_usec - now.tv_usec) / 1000; if (diff < 0) diff = 0; return diff; } } return -1; /* no pending timeouts */ } /* server main poll() loop */ void main_loop(void) { int i, ret, timeout; #ifdef USE_EPOLL assert( POLLIN == EPOLLIN ); assert( POLLOUT == EPOLLOUT ); assert( POLLERR == EPOLLERR ); assert( POLLHUP == EPOLLHUP ); if (epoll_fd != -1) { while (active_users) { timeout = get_next_timeout(); if (!active_users) break; /* last user removed by a timeout */ if (epoll_fd == -1) break; /* an error occurred with epoll */ ret = epoll_wait( epoll_fd, epoll_events, allocated_users, timeout ); /* put the events into the pollfd array first, like poll does */ for (i = 0; i < ret; i++) { int user = epoll_events[i].data.u32; pollfd[user].revents = epoll_events[i].events; } /* read events from the pollfd array, as set_fd_events may modify them */ for (i = 0; i < ret; i++) { int user = epoll_events[i].data.u32; if (pollfd[user].revents) fd_poll_event( poll_users[user], pollfd[user].revents ); } } } /* fall through to normal poll loop */ #endif /* USE_EPOLL */ while (active_users) { timeout = get_next_timeout(); if (!active_users) break; /* last user removed by a timeout */ ret = poll( pollfd, nb_users, timeout ); if (ret > 0) { for (i = 0; i < nb_users; i++) { if (pollfd[i].revents) { fd_poll_event( poll_users[i], pollfd[i].revents ); if (!--ret) break; } } } } } /****************************************************************/ /* inode functions */ #define HASH_SIZE 37 static struct list inode_hash[HASH_SIZE]; /* close all pending file descriptors in the closed list */ static void inode_close_pending( struct inode *inode ) { struct list *ptr = list_head( &inode->closed ); while (ptr) { struct closed_fd *fd = LIST_ENTRY( ptr, struct closed_fd, entry ); struct list *next = list_next( &inode->closed, ptr ); if (fd->fd != -1) { close( fd->fd ); fd->fd = -1; } if (!fd->unlink) /* get rid of it unless there's an unlink pending on that file */ { list_remove( ptr ); free( fd ); } ptr = next; } } static void inode_dump( struct object *obj, int verbose ) { struct inode *inode = (struct inode *)obj; fprintf( stderr, "Inode dev=" ); DUMP_LONG_LONG( inode->dev ); fprintf( stderr, " ino=" ); DUMP_LONG_LONG( inode->ino ); fprintf( stderr, "\n" ); } static void inode_destroy( struct object *obj ) { struct inode *inode = (struct inode *)obj; struct list *ptr; assert( list_empty(&inode->open) ); assert( list_empty(&inode->locks) ); list_remove( &inode->entry ); while ((ptr = list_head( &inode->closed ))) { struct closed_fd *fd = LIST_ENTRY( ptr, struct closed_fd, entry ); list_remove( ptr ); if (fd->fd != -1) close( fd->fd ); if (fd->unlink[0]) { /* make sure it is still the same file */ struct stat st; if (!stat( fd->unlink, &st ) && st.st_dev == inode->dev && st.st_ino == inode->ino) { if (S_ISDIR(st.st_mode)) rmdir( fd->unlink ); else unlink( fd->unlink ); } } free( fd ); } } /* retrieve the inode object for a given fd, creating it if needed */ static struct inode *get_inode( dev_t dev, ino_t ino ) { struct list *ptr; struct inode *inode; unsigned int hash = (dev ^ ino) % HASH_SIZE; if (inode_hash[hash].next) { LIST_FOR_EACH( ptr, &inode_hash[hash] ) { inode = LIST_ENTRY( ptr, struct inode, entry ); if (inode->dev == dev && inode->ino == ino) return (struct inode *)grab_object( inode ); } } else list_init( &inode_hash[hash] ); /* not found, create it */ if ((inode = alloc_object( &inode_ops ))) { inode->hash = hash; inode->dev = dev; inode->ino = ino; list_init( &inode->open ); list_init( &inode->locks ); list_init( &inode->closed ); list_add_head( &inode_hash[hash], &inode->entry ); } return inode; } /* add fd to the indoe list of file descriptors to close */ static void inode_add_closed_fd( struct inode *inode, struct closed_fd *fd ) { if (!list_empty( &inode->locks )) { list_add_head( &inode->closed, &fd->entry ); } else if (fd->unlink[0]) /* close the fd but keep the structure around for unlink */ { close( fd->fd ); fd->fd = -1; list_add_head( &inode->closed, &fd->entry ); } else /* no locks on this inode and no unlink, get rid of the fd */ { close( fd->fd ); free( fd ); } } /****************************************************************/ /* file lock functions */ static void file_lock_dump( struct object *obj, int verbose ) { struct file_lock *lock = (struct file_lock *)obj; fprintf( stderr, "Lock %s fd=%p proc=%p start=", lock->shared ? "shared" : "excl", lock->fd, lock->process ); DUMP_LONG_LONG( lock->start ); fprintf( stderr, " end=" ); DUMP_LONG_LONG( lock->end ); fprintf( stderr, "\n" ); } static int file_lock_signaled( struct object *obj, struct thread *thread ) { struct file_lock *lock = (struct file_lock *)obj; /* lock is signaled if it has lost its owner */ return !lock->process; } /* set (or remove) a Unix lock if possible for the given range */ static int set_unix_lock( struct fd *fd, file_pos_t start, file_pos_t end, int type ) { struct flock fl; if (!fd->fs_locks) return 1; /* no fs locks possible for this fd */ for (;;) { if (start == end) return 1; /* can't set zero-byte lock */ if (start > max_unix_offset) return 1; /* ignore it */ fl.l_type = type; fl.l_whence = SEEK_SET; fl.l_start = start; if (!end || end > max_unix_offset) fl.l_len = 0; else fl.l_len = end - start; if (fcntl( fd->unix_fd, F_SETLK, &fl ) != -1) return 1; switch(errno) { case EACCES: /* check whether locks work at all on this file system */ if (fcntl( fd->unix_fd, F_GETLK, &fl ) != -1) { set_error( STATUS_FILE_LOCK_CONFLICT ); return 0; } /* fall through */ case EIO: case ENOLCK: /* no locking on this fs, just ignore it */ fd->fs_locks = 0; return 1; case EAGAIN: set_error( STATUS_FILE_LOCK_CONFLICT ); return 0; case EBADF: /* this can happen if we try to set a write lock on a read-only file */ /* we just ignore that error */ if (fl.l_type == F_WRLCK) return 1; set_error( STATUS_ACCESS_DENIED ); return 0; #ifdef EOVERFLOW case EOVERFLOW: #endif case EINVAL: /* this can happen if off_t is 64-bit but the kernel only supports 32-bit */ /* in that case we shrink the limit and retry */ if (max_unix_offset > INT_MAX) { max_unix_offset = INT_MAX; break; /* retry */ } /* fall through */ default: file_set_error(); return 0; } } } /* check if interval [start;end) overlaps the lock */ inline static int lock_overlaps( struct file_lock *lock, file_pos_t start, file_pos_t end ) { if (lock->end && start >= lock->end) return 0; if (end && lock->start >= end) return 0; return 1; } /* remove Unix locks for all bytes in the specified area that are no longer locked */ static void remove_unix_locks( struct fd *fd, file_pos_t start, file_pos_t end ) { struct hole { struct hole *next; struct hole *prev; file_pos_t start; file_pos_t end; } *first, *cur, *next, *buffer; struct list *ptr; int count = 0; if (!fd->inode) return; if (!fd->fs_locks) return; if (start == end || start > max_unix_offset) return; if (!end || end > max_unix_offset) end = max_unix_offset + 1; /* count the number of locks overlapping the specified area */ LIST_FOR_EACH( ptr, &fd->inode->locks ) { struct file_lock *lock = LIST_ENTRY( ptr, struct file_lock, inode_entry ); if (lock->start == lock->end) continue; if (lock_overlaps( lock, start, end )) count++; } if (!count) /* no locks at all, we can unlock everything */ { set_unix_lock( fd, start, end, F_UNLCK ); return; } /* allocate space for the list of holes */ /* max. number of holes is number of locks + 1 */ if (!(buffer = malloc( sizeof(*buffer) * (count+1) ))) return; first = buffer; first->next = NULL; first->prev = NULL; first->start = start; first->end = end; next = first + 1; /* build a sorted list of unlocked holes in the specified area */ LIST_FOR_EACH( ptr, &fd->inode->locks ) { struct file_lock *lock = LIST_ENTRY( ptr, struct file_lock, inode_entry ); if (lock->start == lock->end) continue; if (!lock_overlaps( lock, start, end )) continue; /* go through all the holes touched by this lock */ for (cur = first; cur; cur = cur->next) { if (cur->end <= lock->start) continue; /* hole is before start of lock */ if (lock->end && cur->start >= lock->end) break; /* hole is after end of lock */ /* now we know that lock is overlapping hole */ if (cur->start >= lock->start) /* lock starts before hole, shrink from start */ { cur->start = lock->end; if (cur->start && cur->start < cur->end) break; /* done with this lock */ /* now hole is empty, remove it */ if (cur->next) cur->next->prev = cur->prev; if (cur->prev) cur->prev->next = cur->next; else if (!(first = cur->next)) goto done; /* no more holes at all */ } else if (!lock->end || cur->end <= lock->end) /* lock larger than hole, shrink from end */ { cur->end = lock->start; assert( cur->start < cur->end ); } else /* lock is in the middle of hole, split hole in two */ { next->prev = cur; next->next = cur->next; cur->next = next; next->start = lock->end; next->end = cur->end; cur->end = lock->start; assert( next->start < next->end ); assert( cur->end < next->start ); next++; break; /* done with this lock */ } } } /* clear Unix locks for all the holes */ for (cur = first; cur; cur = cur->next) set_unix_lock( fd, cur->start, cur->end, F_UNLCK ); done: free( buffer ); } /* create a new lock on a fd */ static struct file_lock *add_lock( struct fd *fd, int shared, file_pos_t start, file_pos_t end ) { struct file_lock *lock; if (!fd->inode) /* not a regular file */ { set_error( STATUS_INVALID_HANDLE ); return NULL; } if (!(lock = alloc_object( &file_lock_ops ))) return NULL; lock->shared = shared; lock->start = start; lock->end = end; lock->fd = fd; lock->process = current->process; /* now try to set a Unix lock */ if (!set_unix_lock( lock->fd, lock->start, lock->end, lock->shared ? F_RDLCK : F_WRLCK )) { release_object( lock ); return NULL; } list_add_head( &fd->locks, &lock->fd_entry ); list_add_head( &fd->inode->locks, &lock->inode_entry ); list_add_head( &lock->process->locks, &lock->proc_entry ); return lock; } /* remove an existing lock */ static void remove_lock( struct file_lock *lock, int remove_unix ) { struct inode *inode = lock->fd->inode; list_remove( &lock->fd_entry ); list_remove( &lock->inode_entry ); list_remove( &lock->proc_entry ); if (remove_unix) remove_unix_locks( lock->fd, lock->start, lock->end ); if (list_empty( &inode->locks )) inode_close_pending( inode ); lock->process = NULL; wake_up( &lock->obj, 0 ); release_object( lock ); } /* remove all locks owned by a given process */ void remove_process_locks( struct process *process ) { struct list *ptr; while ((ptr = list_head( &process->locks ))) { struct file_lock *lock = LIST_ENTRY( ptr, struct file_lock, proc_entry ); remove_lock( lock, 1 ); /* this removes it from the list */ } } /* remove all locks on a given fd */ static void remove_fd_locks( struct fd *fd ) { file_pos_t start = FILE_POS_T_MAX, end = 0; struct list *ptr; while ((ptr = list_head( &fd->locks ))) { struct file_lock *lock = LIST_ENTRY( ptr, struct file_lock, fd_entry ); if (lock->start < start) start = lock->start; if (!lock->end || lock->end > end) end = lock->end - 1; remove_lock( lock, 0 ); } if (start < end) remove_unix_locks( fd, start, end + 1 ); } /* add a lock on an fd */ /* returns handle to wait on */ obj_handle_t lock_fd( struct fd *fd, file_pos_t start, file_pos_t count, int shared, int wait ) { struct list *ptr; file_pos_t end = start + count; /* don't allow wrapping locks */ if (end && end < start) { set_error( STATUS_INVALID_PARAMETER ); return 0; } /* check if another lock on that file overlaps the area */ LIST_FOR_EACH( ptr, &fd->inode->locks ) { struct file_lock *lock = LIST_ENTRY( ptr, struct file_lock, inode_entry ); if (!lock_overlaps( lock, start, end )) continue; if (lock->shared && shared) continue; /* found one */ if (!wait) { set_error( STATUS_FILE_LOCK_CONFLICT ); return 0; } set_error( STATUS_PENDING ); return alloc_handle( current->process, lock, SYNCHRONIZE, 0 ); } /* not found, add it */ if (add_lock( fd, shared, start, end )) return 0; if (get_error() == STATUS_FILE_LOCK_CONFLICT) { /* Unix lock conflict -> tell client to wait and retry */ if (wait) set_error( STATUS_PENDING ); } return 0; } /* remove a lock on an fd */ void unlock_fd( struct fd *fd, file_pos_t start, file_pos_t count ) { struct list *ptr; file_pos_t end = start + count; /* find an existing lock with the exact same parameters */ LIST_FOR_EACH( ptr, &fd->locks ) { struct file_lock *lock = LIST_ENTRY( ptr, struct file_lock, fd_entry ); if ((lock->start == start) && (lock->end == end)) { remove_lock( lock, 1 ); return; } } set_error( STATUS_FILE_LOCK_CONFLICT ); } /****************************************************************/ /* asynchronous operations support */ struct async { struct thread *thread; void *apc; void *user; void *sb; struct timeout_user *timeout; struct list entry; }; /* notifies client thread of new status of its async request */ /* destroys the server side of it */ static void async_terminate( struct async *async, int status ) { thread_queue_apc( async->thread, NULL, async->apc, APC_ASYNC_IO, 1, async->user, async->sb, (void *)status ); if (async->timeout) remove_timeout_user( async->timeout ); async->timeout = NULL; list_remove( &async->entry ); release_object( async->thread ); free( async ); } /* cb for timeout on an async request */ static void async_callback(void *private) { struct async *async = (struct async *)private; /* fprintf(stderr, "async timeout out %p\n", async); */ async->timeout = NULL; async_terminate( async, STATUS_TIMEOUT ); } /* create an async on a given queue of a fd */ struct async *create_async(struct thread *thread, int* timeout, struct list *queue, void *io_apc, void *io_user, void* io_sb) { struct async *async = mem_alloc( sizeof(struct async) ); if (!async) return NULL; async->thread = (struct thread *)grab_object(thread); async->apc = io_apc; async->user = io_user; async->sb = io_sb; list_add_tail( queue, &async->entry ); if (timeout) { struct timeval when; gettimeofday( &when, NULL ); add_timeout( &when, *timeout ); async->timeout = add_timeout_user( &when, async_callback, async ); } else async->timeout = NULL; return async; } /* terminate the async operation at the head of the queue */ void async_terminate_head( struct list *queue, int status ) { struct list *ptr = list_head( queue ); if (ptr) async_terminate( LIST_ENTRY( ptr, struct async, entry ), status ); } /****************************************************************/ /* file descriptor functions */ static void fd_dump( struct object *obj, int verbose ) { struct fd *fd = (struct fd *)obj; fprintf( stderr, "Fd unix_fd=%d user=%p", fd->unix_fd, fd->user ); if (fd->inode) fprintf( stderr, " inode=%p unlink='%s'", fd->inode, fd->closed->unlink ); fprintf( stderr, "\n" ); } static void fd_destroy( struct object *obj ) { struct fd *fd = (struct fd *)obj; async_terminate_queue( &fd->read_q, STATUS_CANCELLED ); async_terminate_queue( &fd->write_q, STATUS_CANCELLED ); remove_fd_locks( fd ); list_remove( &fd->inode_entry ); if (fd->poll_index != -1) remove_poll_user( fd, fd->poll_index ); if (fd->inode) { inode_add_closed_fd( fd->inode, fd->closed ); release_object( fd->inode ); } else /* no inode, close it right away */ { if (fd->unix_fd != -1) close( fd->unix_fd ); } } /* set the events that select waits for on this fd */ void set_fd_events( struct fd *fd, int events ) { int user = fd->poll_index; assert( poll_users[user] == fd ); set_fd_epoll_events( fd, user, events ); if (events == -1) /* stop waiting on this fd completely */ { pollfd[user].fd = -1; pollfd[user].events = POLLERR; pollfd[user].revents = 0; } else if (pollfd[user].fd != -1 || !pollfd[user].events) { pollfd[user].fd = fd->unix_fd; pollfd[user].events = events; } } /* allocate an fd object, without setting the unix fd yet */ struct fd *alloc_fd( const struct fd_ops *fd_user_ops, struct object *user ) { struct fd *fd = alloc_object( &fd_ops ); if (!fd) return NULL; fd->fd_ops = fd_user_ops; fd->user = user; fd->inode = NULL; fd->closed = NULL; fd->access = 0; fd->sharing = 0; fd->unix_fd = -1; fd->fs_locks = 1; fd->poll_index = -1; list_init( &fd->inode_entry ); list_init( &fd->locks ); list_init( &fd->read_q ); list_init( &fd->write_q ); if ((fd->poll_index = add_poll_user( fd )) == -1) { release_object( fd ); return NULL; } return fd; } /* check if the desired access is possible without violating */ /* the sharing mode of other opens of the same file */ static int check_sharing( struct fd *fd, unsigned int access, unsigned int sharing ) { unsigned int existing_sharing = FILE_SHARE_READ | FILE_SHARE_WRITE | FILE_SHARE_DELETE; unsigned int existing_access = 0; int unlink = 0; struct list *ptr; /* if access mode is 0, sharing mode is ignored */ if (!access) sharing = existing_sharing; fd->access = access; fd->sharing = sharing; LIST_FOR_EACH( ptr, &fd->inode->open ) { struct fd *fd_ptr = LIST_ENTRY( ptr, struct fd, inode_entry ); if (fd_ptr != fd) { existing_sharing &= fd_ptr->sharing; existing_access |= fd_ptr->access; if (fd_ptr->closed->unlink[0]) unlink = 1; } } if ((access & GENERIC_READ) && !(existing_sharing & FILE_SHARE_READ)) return 0; if ((access & GENERIC_WRITE) && !(existing_sharing & FILE_SHARE_WRITE)) return 0; if ((existing_access & GENERIC_READ) && !(sharing & FILE_SHARE_READ)) return 0; if ((existing_access & GENERIC_WRITE) && !(sharing & FILE_SHARE_WRITE)) return 0; if (fd->closed->unlink[0] && !(existing_sharing & FILE_SHARE_DELETE)) return 0; if (unlink && !(sharing & FILE_SHARE_DELETE)) return 0; return 1; } /* open() wrapper using a struct fd */ /* the fd must have been created with alloc_fd */ /* on error the fd object is released */ struct fd *open_fd( struct fd *fd, const char *name, int flags, mode_t *mode, unsigned int access, unsigned int sharing, unsigned int options ) { struct stat st; struct closed_fd *closed_fd; const char *unlink_name = ""; assert( fd->unix_fd == -1 ); if (options & FILE_DELETE_ON_CLOSE) unlink_name = name; if (!(closed_fd = mem_alloc( sizeof(*closed_fd) + strlen(unlink_name) ))) { release_object( fd ); return NULL; } /* create the directory if needed */ if ((options & FILE_DIRECTORY_FILE) && (flags & O_CREAT)) { if (mkdir( name, 0777 ) == -1) { if (errno != EEXIST || (flags & O_EXCL)) { file_set_error(); release_object( fd ); free( closed_fd ); return NULL; } } flags &= ~(O_CREAT | O_EXCL | O_TRUNC); } if ((fd->unix_fd = open( name, flags & ~O_TRUNC, *mode )) == -1) { file_set_error(); release_object( fd ); free( closed_fd ); return NULL; } closed_fd->fd = fd->unix_fd; closed_fd->unlink[0] = 0; fstat( fd->unix_fd, &st ); *mode = st.st_mode; /* only bother with an inode for normal files and directories */ if (S_ISREG(st.st_mode) || S_ISDIR(st.st_mode)) { struct inode *inode = get_inode( st.st_dev, st.st_ino ); if (!inode) { /* we can close the fd because there are no others open on the same file, * otherwise we wouldn't have failed to allocate a new inode */ goto error; } fd->inode = inode; fd->closed = closed_fd; list_add_head( &inode->open, &fd->inode_entry ); /* check directory options */ if ((options & FILE_DIRECTORY_FILE) && !S_ISDIR(st.st_mode)) { release_object( fd ); set_error( STATUS_NOT_A_DIRECTORY ); return NULL; } if ((options & FILE_NON_DIRECTORY_FILE) && S_ISDIR(st.st_mode)) { release_object( fd ); set_error( STATUS_FILE_IS_A_DIRECTORY ); return NULL; } if (!check_sharing( fd, access, sharing )) { release_object( fd ); set_error( STATUS_SHARING_VIOLATION ); return NULL; } strcpy( closed_fd->unlink, unlink_name ); if (flags & O_TRUNC) ftruncate( fd->unix_fd, 0 ); } else /* special file */ { if (options & FILE_DIRECTORY_FILE) { set_error( STATUS_NOT_A_DIRECTORY ); goto error; } if (unlink_name[0]) /* we can't unlink special files */ { set_error( STATUS_INVALID_PARAMETER ); goto error; } free( closed_fd ); } return fd; error: release_object( fd ); free( closed_fd ); return NULL; } /* create an fd for an anonymous file */ /* if the function fails the unix fd is closed */ struct fd *create_anonymous_fd( const struct fd_ops *fd_user_ops, int unix_fd, struct object *user ) { struct fd *fd = alloc_fd( fd_user_ops, user ); if (fd) { fd->unix_fd = unix_fd; return fd; } close( unix_fd ); return NULL; } /* retrieve the object that is using an fd */ void *get_fd_user( struct fd *fd ) { return fd->user; } /* retrieve the unix fd for an object */ int get_unix_fd( struct fd *fd ) { return fd->unix_fd; } /* check if two file descriptors point to the same file */ int is_same_file_fd( struct fd *fd1, struct fd *fd2 ) { return fd1->inode == fd2->inode; } /* callback for event happening in the main poll() loop */ void fd_poll_event( struct fd *fd, int event ) { return fd->fd_ops->poll_event( fd, event ); } /* check if events are pending and if yes return which one(s) */ int check_fd_events( struct fd *fd, int events ) { struct pollfd pfd; pfd.fd = fd->unix_fd; pfd.events = events; if (poll( &pfd, 1, 0 ) <= 0) return 0; return pfd.revents; } /* default add_queue() routine for objects that poll() on an fd */ int default_fd_add_queue( struct object *obj, struct wait_queue_entry *entry ) { struct fd *fd = get_obj_fd( obj ); if (!fd) return 0; if (list_empty( &obj->wait_queue )) /* first on the queue */ set_fd_events( fd, fd->fd_ops->get_poll_events( fd ) ); add_queue( obj, entry ); release_object( fd ); return 1; } /* default remove_queue() routine for objects that poll() on an fd */ void default_fd_remove_queue( struct object *obj, struct wait_queue_entry *entry ) { struct fd *fd = get_obj_fd( obj ); grab_object( obj ); remove_queue( obj, entry ); if (list_empty( &obj->wait_queue )) /* last on the queue is gone */ set_fd_events( fd, 0 ); release_object( obj ); release_object( fd ); } /* default signaled() routine for objects that poll() on an fd */ int default_fd_signaled( struct object *obj, struct thread *thread ) { int events, ret; struct fd *fd = get_obj_fd( obj ); if (fd->inode) return 1; /* regular files are always signaled */ events = fd->fd_ops->get_poll_events( fd ); ret = check_fd_events( fd, events ) != 0; if (ret) set_fd_events( fd, 0 ); /* stop waiting on select() if we are signaled */ else if (!list_empty( &obj->wait_queue )) set_fd_events( fd, events ); /* restart waiting on poll() if we are no longer signaled */ release_object( fd ); return ret; } int default_fd_get_poll_events( struct fd *fd ) { int events = 0; if( !list_empty( &fd->read_q )) events |= POLLIN; if( !list_empty( &fd->write_q )) events |= POLLOUT; return events; } /* default handler for poll() events */ void default_poll_event( struct fd *fd, int event ) { if (!list_empty( &fd->read_q ) && (POLLIN & event) ) { async_terminate_head( &fd->read_q, STATUS_ALERTED ); return; } if (!list_empty( &fd->write_q ) && (POLLOUT & event) ) { async_terminate_head( &fd->write_q, STATUS_ALERTED ); return; } /* if an error occurred, stop polling this fd to avoid busy-looping */ if (event & (POLLERR | POLLHUP)) set_fd_events( fd, -1 ); wake_up( fd->user, 0 ); } void default_fd_queue_async( struct fd *fd, void *apc, void *user, void *io_sb, int type, int count ) { struct list *queue; int events; if (!(fd->fd_ops->get_file_info( fd ) & FD_FLAG_OVERLAPPED)) { set_error( STATUS_INVALID_HANDLE ); return; } switch (type) { case ASYNC_TYPE_READ: queue = &fd->read_q; break; case ASYNC_TYPE_WRITE: queue = &fd->write_q; break; default: set_error( STATUS_INVALID_PARAMETER ); return; } if (!create_async( current, NULL, queue, apc, user, io_sb )) return; /* Check if the new pending request can be served immediately */ events = check_fd_events( fd, fd->fd_ops->get_poll_events( fd ) ); if (events) fd->fd_ops->poll_event( fd, events ); set_fd_events( fd, fd->fd_ops->get_poll_events( fd ) ); } void default_fd_cancel_async( struct fd *fd ) { async_terminate_queue( &fd->read_q, STATUS_CANCELLED ); async_terminate_queue( &fd->write_q, STATUS_CANCELLED ); } /* default flush() routine */ int no_flush( struct fd *fd, struct event **event ) { set_error( STATUS_OBJECT_TYPE_MISMATCH ); return 0; } /* default get_file_info() routine */ int no_get_file_info( struct fd *fd ) { set_error( STATUS_OBJECT_TYPE_MISMATCH ); return 0; } /* default queue_async() routine */ void no_queue_async( struct fd *fd, void* apc, void* user, void* io_sb, int type, int count) { set_error( STATUS_OBJECT_TYPE_MISMATCH ); } /* default cancel_async() routine */ void no_cancel_async( struct fd *fd ) { set_error( STATUS_OBJECT_TYPE_MISMATCH ); } /* same as get_handle_obj but retrieve the struct fd associated to the object */ static struct fd *get_handle_fd_obj( struct process *process, obj_handle_t handle, unsigned int access ) { struct fd *fd = NULL; struct object *obj; if ((obj = get_handle_obj( process, handle, access, NULL ))) { fd = get_obj_fd( obj ); release_object( obj ); } return fd; } /* flush a file buffers */ DECL_HANDLER(flush_file) { struct fd *fd = get_handle_fd_obj( current->process, req->handle, 0 ); struct event * event = NULL; if (fd) { fd->fd_ops->flush( fd, &event ); if ( event ) { reply->event = alloc_handle( current->process, event, SYNCHRONIZE, 0 ); } release_object( fd ); } } /* get a Unix fd to access a file */ DECL_HANDLER(get_handle_fd) { struct fd *fd; reply->fd = -1; if ((fd = get_handle_fd_obj( current->process, req->handle, req->access ))) { int unix_fd = get_handle_unix_fd( current->process, req->handle, req->access ); if (unix_fd != -1) reply->fd = unix_fd; else if (!get_error()) { assert( fd->unix_fd != -1 ); send_client_fd( current->process, fd->unix_fd, req->handle ); } reply->flags = fd->fd_ops->get_file_info( fd ); release_object( fd ); } } /* create / reschedule an async I/O */ DECL_HANDLER(register_async) { struct fd *fd = get_handle_fd_obj( current->process, req->handle, 0 ); /* * The queue_async method must do the following: * * 1. Get the async_queue for the request of given type. * 2. Create a new asynchronous request for the selected queue * 3. Carry out any operations necessary to adjust the object's poll events * Usually: set_elect_events (obj, obj->ops->get_poll_events()). * 4. When the async request is triggered, then send back (with a proper APC) * the trigger (STATUS_ALERTED) to the thread that posted the request. * async_destroy() is to be called: it will both notify the sender about * the trigger and destroy the request by itself * See also the implementations in file.c, serial.c, and sock.c. */ if (fd) { fd->fd_ops->queue_async( fd, req->io_apc, req->io_user, req->io_sb, req->type, req->count ); release_object( fd ); } } /* cancels all async I/O */ DECL_HANDLER(cancel_async) { struct fd *fd = get_handle_fd_obj( current->process, req->handle, 0 ); if (fd) { /* Note: we don't kill the queued APC_ASYNC_IO on this thread because * NtCancelIoFile() will force the pending APC to be run. Since, * Windows only guarantees that the current thread will have no async * operation on the current fd when NtCancelIoFile returns, this shall * do the work. */ fd->fd_ops->cancel_async( fd ); release_object( fd ); } }