/* ==== fd_kern.c ============================================================ * Copyright (c) 1993, 1994 by Chris Provenzano, proven@mit.edu * All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * 3. All advertising materials mentioning features or use of this software * must display the following acknowledgement: * This product includes software developed by Chris Provenzano. * 4. The name of Chris Provenzano may not be used to endorse or promote * products derived from this software without specific prior written * permission. * * THIS SOFTWARE IS PROVIDED BY CHRIS PROVENZANO ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL CHRIS PROVENZANO BE LIABLE FOR ANY * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. * * Description : Deals with the valid kernel fds. * * 1.00 93/09/27 proven * -Started coding this file. * * 1.01 93/11/13 proven * -The functions readv() and writev() added. */ #ifndef lint static const char rcsid[] = "$Id: fd_kern.c,v 1.3 1994/02/07 22:04:16 proven Exp $ $provenid: fd_kern.c,v 1.7 1994/02/07 02:18:49 proven Exp $"; #endif #include #include #include #include #include #include #include #include #include #include #include /* ========================================================================== * Variables used by both fd_kern_poll and fd_kern_wait */ static struct pthread *fd_wait_read, *fd_wait_write; static fd_set fd_set_read, fd_set_write; /* ========================================================================== * fd_kern_poll() * * Called only from context_switch(). The kernel must be locked. * * This function uses a linked list of waiting pthreads, NOT a queue. */ static semaphore fd_wait_lock = SEMAPHORE_CLEAR; void fd_kern_poll() { struct timeval __fd_kern_poll_timeout = { 0, 0 }; struct pthread **pthread; semaphore *lock; int count; /* If someone has the lock then they are in RUNNING state, just return */ lock = &fd_wait_lock; if (SEMAPHORE_TEST_AND_SET(lock)) { return; } if (fd_wait_read || fd_wait_write) { for (pthread = &fd_wait_read; *pthread; pthread = &((*pthread)->next)) { FD_SET((*pthread)->fd, &fd_set_read); } for (pthread = &fd_wait_write; *pthread; pthread = &((*pthread)->next)) { FD_SET((*pthread)->fd, &fd_set_write); } if ((count = machdep_sys_select(dtablesize, &fd_set_read, &fd_set_write, NULL, &__fd_kern_poll_timeout)) < OK) { if (count == -EINTR) { SEMAPHORE_RESET(lock); return; } PANIC(); } for (pthread = &fd_wait_read; count && *pthread; ) { if (FD_ISSET((*pthread)->fd, &fd_set_read)) { /* Get lock on thread */ (*pthread)->state = PS_RUNNING; *pthread = (*pthread)->next; count--; continue; } pthread = &((*pthread)->next); } for (pthread = &fd_wait_write; count && *pthread; ) { if (FD_ISSET((*pthread)->fd, &fd_set_write)) { semaphore *plock; /* Get lock on thread */ plock = &(*pthread)->lock; if (!(SEMAPHORE_TEST_AND_SET(plock))) { /* Thread locked, skip it. */ (*pthread)->state = PS_RUNNING; *pthread = (*pthread)->next; SEMAPHORE_RESET(plock); } count--; continue; } pthread = &((*pthread)->next); } } SEMAPHORE_RESET(lock); } /* ========================================================================== * fd_kern_wait() * * Called when there is no active thread to run. */ extern struct timeval __fd_kern_wait_timeout; void fd_kern_wait() { struct pthread **pthread; sigset_t sig_to_block; int count; if (fd_wait_read || fd_wait_write) { for (pthread = &fd_wait_read; *pthread; pthread = &((*pthread)->next)) { FD_SET((*pthread)->fd, &fd_set_read); } for (pthread = &fd_wait_write; *pthread; pthread = &((*pthread)->next)) { FD_SET((*pthread)->fd, &fd_set_write); } /* Turn off interrupts for real while we set the timer. */ sigfillset(&sig_to_block); sigprocmask(SIG_BLOCK, &sig_to_block, NULL); machdep_unset_thread_timer(); __fd_kern_wait_timeout.tv_usec = 0; __fd_kern_wait_timeout.tv_sec = 3600; sigprocmask(SIG_UNBLOCK, &sig_to_block, NULL); /* * There is a small but finite chance that an interrupt will * occure between the unblock and the select. Because of this * sig_handler_real() sets the value of __fd_kern_wait_timeout * to zero causing the select to do a poll instead of a wait. */ while ((count = machdep_sys_select(dtablesize, &fd_set_read, &fd_set_write, NULL, &__fd_kern_wait_timeout)) < OK) { if (count == -EINTR) { return; } PANIC(); } for (pthread = &fd_wait_read; count && *pthread; ) { if (FD_ISSET((*pthread)->fd, &fd_set_read)) { /* Get lock on thread */ (*pthread)->state = PS_RUNNING; *pthread = (*pthread)->next; count--; continue; } pthread = &((*pthread)->next); } for (pthread = &fd_wait_write; count && *pthread; ) { if (FD_ISSET((*pthread)->fd, &fd_set_write)) { semaphore *plock; /* Get lock on thread */ plock = &(*pthread)->lock; if (!(SEMAPHORE_TEST_AND_SET(plock))) { /* Thread locked, skip it. */ (*pthread)->state = PS_RUNNING; *pthread = (*pthread)->next; SEMAPHORE_RESET(plock); } count--; continue; } pthread = &((*pthread)->next); } } else { /* No threads, waiting on I/O, do a sigsuspend */ sig_handler_pause(); } } /* ========================================================================== * Special Note: All operations return the errno as a negative of the errno * listed in errno.h * ======================================================================= */ /* ========================================================================== * read() */ ssize_t __fd_kern_read(int fd, int flags, void *buf, size_t nbytes) { semaphore *lock, *plock; int ret; while ((ret = machdep_sys_read(fd, buf, nbytes)) < OK) { if (ret == -EWOULDBLOCK) { /* Lock queue */ lock = &fd_wait_lock; while (SEMAPHORE_TEST_AND_SET(lock)) { pthread_yield(); } /* Lock pthread */ plock = &(pthread_run->lock); while (SEMAPHORE_TEST_AND_SET(plock)) { pthread_yield(); } /* queue pthread for a FDR_WAIT */ pthread_run->next = fd_wait_read; fd_wait_read = pthread_run; pthread_run->fd = fd; SEMAPHORE_RESET(lock); reschedule(PS_FDR_WAIT); } else { pthread_run->error = -ret; ret = NOTOK; break; } } return(ret); } /* ========================================================================== * readv() */ int __fd_kern_readv(int fd, int flags, struct iovec *iov, int iovcnt) { semaphore *lock, *plock; int ret; while ((ret = machdep_sys_readv(fd, iov, iovcnt)) < OK) { if (ret == -EWOULDBLOCK) { /* Lock queue */ lock = &fd_wait_lock; while (SEMAPHORE_TEST_AND_SET(lock)) { pthread_yield(); } /* Lock pthread */ plock = &(pthread_run->lock); while (SEMAPHORE_TEST_AND_SET(plock)) { pthread_yield(); } /* queue pthread for a FDR_WAIT */ pthread_run->next = fd_wait_read; fd_wait_read = pthread_run; pthread_run->fd = fd; SEMAPHORE_RESET(lock); reschedule(PS_FDR_WAIT); } else { pthread_run->error = -ret; ret = NOTOK; break; } } return(ret); } /* ========================================================================== * write() */ ssize_t __fd_kern_write(int fd, int flags, const void *buf, size_t nbytes) { semaphore *lock, *plock; int ret; while ((ret = machdep_sys_write(fd, buf, nbytes)) < OK) { if (pthread_run->error == -EWOULDBLOCK) { /* Lock queue */ lock = &fd_wait_lock; while (SEMAPHORE_TEST_AND_SET(lock)) { pthread_yield(); } /* Lock pthread */ plock = &(pthread_run->lock); while (SEMAPHORE_TEST_AND_SET(plock)) { pthread_yield(); } /* queue pthread for a FDW_WAIT */ pthread_run->next = fd_wait_write; fd_wait_write = pthread_run; pthread_run->fd = fd; SEMAPHORE_RESET(lock); reschedule(PS_FDW_WAIT); } else { pthread_run->error = ret; break; } } return(ret); } /* ========================================================================== * writev() */ int __fd_kern_writev(int fd, int flags, struct iovec *iov, int iovcnt) { semaphore *lock, *plock; int ret; while ((ret = machdep_sys_writev(fd, iov, iovcnt)) < OK) { if (pthread_run->error == -EWOULDBLOCK) { /* Lock queue */ lock = &fd_wait_lock; while (SEMAPHORE_TEST_AND_SET(lock)) { pthread_yield(); } /* Lock pthread */ plock = &(pthread_run->lock); while (SEMAPHORE_TEST_AND_SET(plock)) { pthread_yield(); } /* queue pthread for a FDW_WAIT */ pthread_run->next = fd_wait_write; fd_wait_write = pthread_run; pthread_run->fd = fd; SEMAPHORE_RESET(lock); reschedule(PS_FDW_WAIT); } else { pthread_run->error = ret; break; } } return(ret); } /* ========================================================================== * For blocking version we really should set an interrupt * fcntl() */ int __fd_kern_fcntl(int fd, int flags, int cmd, int arg) { return(machdep_sys_fcntl(fd, cmd, arg)); } /* ========================================================================== * close() */ int __fd_kern_close(int fd, int flags) { return(machdep_sys_close(fd)); } /* ========================================================================== * lseek() */ int __fd_kern_lseek(int fd, int flags, off_t offset, int whence) { return(machdep_sys_lseek(fd, offset, whence)); } /* * File descriptor operations */ extern machdep_sys_close(); /* Normal file operations */ static struct fd_ops __fd_kern_ops = { __fd_kern_write, __fd_kern_read, __fd_kern_close, __fd_kern_fcntl, __fd_kern_readv, __fd_kern_writev, __fd_kern_lseek }; /* NFS file opperations */ /* FIFO file opperations */ /* Device operations */ /* ========================================================================== * open() * * Because open could potentially block opening a file from a remote * system, we want to make sure the call will timeout. We then try and open * the file, and stat the file to determine what operations we should * associate with the fd. * * This is not done yet * * A reqular file on the local system needs no special treatment. */ int open(const char *path, int flags, ...) { int fd, mode, fd_kern; struct stat stat_buf; va_list ap; /* If pthread scheduling == FIFO set a virtual timer */ if (flags & O_CREAT) { va_start(ap, flags); mode = va_arg(ap, int); va_end(ap); } else { mode = 0; } if (!((fd = fd_allocate()) < OK)) { fd_table[fd]->flags = flags; flags |= __FD_NONBLOCK; if (!((fd_kern = machdep_sys_open(path, flags, mode)) < OK)) { /* fstat the file to determine what type it is */ if (fstat(fd_kern, &stat_buf)) { printf("error %d stating new fd %d\n", errno, fd); } if (S_ISREG(stat_buf.st_mode)) { fd_table[fd]->ops = &(__fd_kern_ops); fd_table[fd]->type = FD_HALF_DUPLEX; } else { fd_table[fd]->ops = &(__fd_kern_ops); fd_table[fd]->type = FD_FULL_DUPLEX; } fd_table[fd]->fd = fd_kern; return(fd); } pthread_run->error = - fd_kern; fd_table[fd]->count = 0; } return(NOTOK); } /* ========================================================================== * fd_kern_init() * * Assume the entry is locked before routine is invoked * * This may change. The problem is setting the fd to nonblocking changes * the parents fd too, which may not be the desired result. */ static fd_kern_init_called = 0; void fd_kern_init(int fd) { if ((fd_table[fd]->flags = machdep_sys_fcntl(fd, F_GETFL, NULL)) >= OK) { machdep_sys_fcntl(fd, F_SETFL, fd_table[fd]->flags | __FD_NONBLOCK); fd_table[fd]->ops = &(__fd_kern_ops); fd_table[fd]->type = FD_HALF_DUPLEX; fd_table[fd]->fd = fd; fd_table[fd]->count = 1; } } /* ========================================================================== * Here are the berkeley socket functions. These are not POSIX. * ======================================================================= */ /* ========================================================================== * socket() */ int socket(int af, int type, int protocol) { int fd, fd_kern; if (!((fd = fd_allocate()) < OK)) { if (!((fd_kern = machdep_sys_socket(af, type, protocol)) < OK)) { machdep_sys_fcntl(fd_kern, F_SETFL, __FD_NONBLOCK); /* Should fstat the file to determine what type it is */ fd_table[fd]->ops = & __fd_kern_ops; fd_table[fd]->type = FD_FULL_DUPLEX; fd_table[fd]->fd = fd_kern; fd_table[fd]->flags = 0; return(fd); } pthread_run->error = - fd_kern; fd_table[fd]->count = 0; } return(NOTOK); } /* ========================================================================== * bind() */ int bind(int fd, const struct sockaddr *name, int namelen) { /* Not much to do in bind */ semaphore *plock; int ret; if ((ret = fd_lock(fd, FD_RDWR)) == OK) { if ((ret = machdep_sys_bind(fd_table[fd]->fd, name, namelen)) < OK) { pthread_run->error = - ret; } fd_unlock(fd, FD_RDWR); } return(ret); } /* ========================================================================== * connect() */ int connect(int fd, const struct sockaddr *name, int namelen) { semaphore *lock, *plock; struct sockaddr tmpname; int ret, tmpnamelen; if ((ret = fd_lock(fd, FD_RDWR)) == OK) { if ((ret = machdep_sys_connect(fd_table[fd]->fd, name, namelen)) < OK) { if ((ret == -EWOULDBLOCK) || (ret == -EINPROGRESS) || (ret == -EALREADY)) { /* Lock queue */ lock = &fd_wait_lock; while (SEMAPHORE_TEST_AND_SET(lock)) { pthread_yield(); } /* Lock pthread */ plock = &(pthread_run->lock); while (SEMAPHORE_TEST_AND_SET(plock)) { pthread_yield(); } /* queue pthread for a FDW_WAIT */ pthread_run->fd = fd_table[fd]->fd.i; pthread_run->next = fd_wait_write; fd_wait_write = pthread_run; SEMAPHORE_RESET(lock); reschedule(PS_FDW_WAIT); /* OK now lets see if it really worked */ if (((ret = machdep_sys_getpeername(fd_table[fd]->fd, &tmpname, &tmpnamelen)) < OK) && (ret == -ENOTCONN)) { /* Get the error, this function should not fail */ machdep_sys_getsockopt(fd_table[fd]->fd, SOL_SOCKET, SO_ERROR, &pthread_run->error, &tmpnamelen); } } else { pthread_run->error = -ret; } } fd_unlock(fd, FD_RDWR); } return(ret); } /* ========================================================================== * accept() */ int accept(int fd, struct sockaddr *name, int *namelen) { semaphore *lock, *plock; int ret, fd_kern; if ((ret = fd_lock(fd, FD_RDWR)) == OK) { while ((fd_kern = machdep_sys_accept(fd_table[fd]->fd, name, namelen)) < OK) { if (fd_kern == -EWOULDBLOCK) { /* Lock queue */ lock = &fd_wait_lock; while (SEMAPHORE_TEST_AND_SET(lock)) { pthread_yield(); } /* Lock pthread */ plock = &(pthread_run->lock); while (SEMAPHORE_TEST_AND_SET(plock)) { pthread_yield(); } /* queue pthread for a FDR_WAIT */ pthread_run->fd = fd_table[fd]->fd.i; pthread_run->next = fd_wait_write; pthread_run->next = fd_wait_read; fd_wait_read = pthread_run; SEMAPHORE_RESET(lock); reschedule(PS_FDR_WAIT); } else { fd_unlock(fd, FD_RDWR); return(fd_kern); } } fd_unlock(fd, FD_RDWR); if (!((ret = fd_allocate()) < OK)) { /* This may be unnecessary */ machdep_sys_fcntl(fd_kern, F_SETFL, __FD_NONBLOCK); /* Should fstat the file to determine what type it is */ fd_table[ret]->ops = & __fd_kern_ops; fd_table[ret]->type = FD_FULL_DUPLEX; fd_table[ret]->fd = fd_kern; fd_table[ret]->flags = 0; } } return(ret); } /* ========================================================================== * listen() */ int listen(int fd, int backlog) { int ret; if ((ret = fd_lock(fd, FD_RDWR)) == OK) { ret = machdep_sys_listen(fd_table[fd]->fd, backlog); fd_unlock(fd, FD_RDWR); } return(ret); }