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Diffstat (limited to 'lib/libc_r/uthread/uthread_fd.c')
-rw-r--r--lib/libc_r/uthread/uthread_fd.c364
1 files changed, 364 insertions, 0 deletions
diff --git a/lib/libc_r/uthread/uthread_fd.c b/lib/libc_r/uthread/uthread_fd.c
new file mode 100644
index 000000000000..b41631aa6269
--- /dev/null
+++ b/lib/libc_r/uthread/uthread_fd.c
@@ -0,0 +1,364 @@
+/*
+ * Copyright (c) 1995 John Birrell <jb@cimlogic.com.au>.
+ * 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 John Birrell.
+ * 4. Neither the name of the author nor the names of any co-contributors
+ * may be used to endorse or promote products derived from this software
+ * without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY JOHN BIRRELL AND CONTRIBUTORS ``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 THE REGENTS OR CONTRIBUTORS 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.
+ *
+ */
+#include <errno.h>
+#include <stdlib.h>
+#ifdef _THREAD_SAFE
+#include <pthread.h>
+#include "pthread_private.h"
+
+int
+_thread_fd_table_init(int fd)
+{
+ int ret = 0;
+ int status;
+
+ /* Block signals: */
+ _thread_kern_sig_block(&status);
+
+ /* Check if the file descriptor is out of range: */
+ if (fd < 0 || fd >= _thread_dtablesize) {
+ /* Return a bad file descriptor error: */
+ _thread_seterrno(_thread_run, EBADF);
+ ret = -1;
+ }
+ /*
+ * Check if memory has already been allocated for this file
+ * descriptor:
+ */
+ else if (_thread_fd_table[fd] != NULL) {
+ }
+ /* Allocate memory for the file descriptor table entry: */
+ else if ((_thread_fd_table[fd] = (struct fd_table_entry *) malloc(sizeof(struct fd_table_entry))) == NULL) {
+ /* Return a bad file descriptor error: */
+ _thread_seterrno(_thread_run, EBADF);
+ ret = -1;
+ } else {
+ /* Initialise the file locks: */
+ _thread_fd_table[fd]->r_owner = NULL;
+ _thread_fd_table[fd]->w_owner = NULL;
+ _thread_fd_table[fd]->r_fname = NULL;
+ _thread_fd_table[fd]->w_fname = NULL;
+ _thread_fd_table[fd]->r_lineno = 0;;
+ _thread_fd_table[fd]->w_lineno = 0;;
+ _thread_fd_table[fd]->r_lockcount = 0;;
+ _thread_fd_table[fd]->w_lockcount = 0;;
+
+ /* Default the flags: */
+ _thread_fd_table[fd]->flags = 0;
+
+ /* Initialise the read/write queues: */
+ _thread_queue_init(&_thread_fd_table[fd]->r_queue);
+ _thread_queue_init(&_thread_fd_table[fd]->w_queue);
+ }
+
+ /* Unblock signals: */
+ _thread_kern_sig_unblock(status);
+
+ /* Return the completion status: */
+ return (ret);
+}
+
+void
+_thread_fd_unlock(int fd, int lock_type)
+{
+ int ret;
+ int status;
+
+ /* Block signals while the file descriptor lock is tested: */
+ _thread_kern_sig_block(&status);
+
+ /*
+ * Check that the file descriptor table is initialised for this
+ * entry:
+ */
+ if ((ret = _thread_fd_table_init(fd)) != 0) {
+ } else {
+ /* Check if the running thread owns the read lock: */
+ if (_thread_fd_table[fd]->r_owner == _thread_run) {
+ /* Check the file descriptor and lock types: */
+ if (lock_type == FD_READ || lock_type == FD_RDWR) {
+ /*
+ * Decrement the read lock count for the
+ * running thread:
+ */
+ _thread_fd_table[fd]->r_lockcount--;
+
+ /*
+ * Check if the running thread still has read
+ * locks on this file descriptor:
+ */
+ if (_thread_fd_table[fd]->r_lockcount != 0) {
+ }
+ /*
+ * Get the next thread in the queue for a
+ * read lock on this file descriptor:
+ */
+ else if ((_thread_fd_table[fd]->r_owner = _thread_queue_deq(&_thread_fd_table[fd]->r_queue)) == NULL) {
+ } else {
+ /*
+ * Set the state of the new owner of
+ * the thread to running:
+ */
+ _thread_fd_table[fd]->r_owner->state = PS_RUNNING;
+
+ /*
+ * Reset the number of read locks.
+ * This will be incremented by the
+ * new owner of the lock when it sees
+ * that it has the lock.
+ */
+ _thread_fd_table[fd]->r_lockcount = 0;
+ }
+ }
+ }
+ /* Check if the running thread owns the write lock: */
+ if (_thread_fd_table[fd]->w_owner == _thread_run) {
+ /* Check the file descriptor and lock types: */
+ if (lock_type == FD_WRITE || lock_type == FD_RDWR) {
+ /*
+ * Decrement the write lock count for the
+ * running thread:
+ */
+ _thread_fd_table[fd]->w_lockcount--;
+
+ /*
+ * Check if the running thread still has
+ * write locks on this file descriptor:
+ */
+ if (_thread_fd_table[fd]->w_lockcount != 0) {
+ }
+ /*
+ * Get the next thread in the queue for a
+ * write lock on this file descriptor:
+ */
+ else if ((_thread_fd_table[fd]->w_owner = _thread_queue_deq(&_thread_fd_table[fd]->w_queue)) == NULL) {
+ } else {
+ /*
+ * Set the state of the new owner of
+ * the thread to running:
+ */
+ _thread_fd_table[fd]->w_owner->state = PS_RUNNING;
+
+ /*
+ * Reset the number of write locks.
+ * This will be incremented by the
+ * new owner of the lock when it
+ * sees that it has the lock.
+ */
+ _thread_fd_table[fd]->w_lockcount = 0;
+ }
+ }
+ }
+ }
+
+ /* Unblock signals again: */
+ _thread_kern_sig_unblock(status);
+
+ /* Nothing to return. */
+ return;
+}
+
+int
+_thread_fd_lock(int fd, int lock_type, struct timespec * timeout,
+ char *fname, int lineno)
+{
+ int ret;
+ int status;
+
+ /* Block signals while the file descriptor lock is tested: */
+ _thread_kern_sig_block(&status);
+
+ /*
+ * Check that the file descriptor table is initialised for this
+ * entry:
+ */
+ if ((ret = _thread_fd_table_init(fd)) != 0) {
+ } else {
+ /* Check the file descriptor and lock types: */
+ if (lock_type == FD_READ || lock_type == FD_RDWR) {
+ /*
+ * Enter a loop to wait for the file descriptor to be
+ * locked for read for the current thread:
+ */
+ while (_thread_fd_table[fd]->r_owner != _thread_run) {
+ /*
+ * Check if the file descriptor is locked by
+ * another thread:
+ */
+ if (_thread_fd_table[fd]->r_owner != NULL) {
+ /*
+ * Another thread has locked the file
+ * descriptor for read, so join the
+ * queue of threads waiting for a
+ * read lock on this file descriptor:
+ */
+ _thread_queue_enq(&_thread_fd_table[fd]->r_queue, _thread_run);
+
+ /*
+ * Save the file descriptor details
+ * in the thread structure for the
+ * running thread:
+ */
+ _thread_run->data.fd.fd = fd;
+ _thread_run->data.fd.branch = lineno;
+ _thread_run->data.fd.fname = fname;
+
+ /* Set the timeout: */
+ _thread_kern_set_timeout(timeout);
+
+ /*
+ * Schedule this thread to wait on
+ * the read lock. It will only be
+ * woken when it becomes the next in
+ * the queue and is granted access
+ * to the lock by the thread
+ * that is unlocking the file
+ * descriptor.
+ */
+ _thread_kern_sched_state(PS_FDLR_WAIT, __FILE__, __LINE__);
+
+ /*
+ * Block signals so that the file
+ * descriptor lock can again be
+ * tested:
+ */
+ _thread_kern_sig_block(NULL);
+ } else {
+ /*
+ * The running thread now owns the
+ * read lock on this file descriptor:
+ */
+ _thread_fd_table[fd]->r_owner = _thread_run;
+
+ /*
+ * Reset the number of read locks for
+ * this file descriptor:
+ */
+ _thread_fd_table[fd]->r_lockcount = 0;
+
+ /*
+ * Save the source file details for
+ * debugging:
+ */
+ _thread_fd_table[fd]->r_fname = fname;
+ _thread_fd_table[fd]->r_lineno = lineno;
+ }
+ }
+
+ /* Increment the read lock count: */
+ _thread_fd_table[fd]->r_lockcount++;
+ }
+ /* Check the file descriptor and lock types: */
+ if (lock_type == FD_WRITE || lock_type == FD_RDWR) {
+ /*
+ * Enter a loop to wait for the file descriptor to be
+ * locked for write for the current thread:
+ */
+ while (_thread_fd_table[fd]->w_owner != _thread_run) {
+ /*
+ * Check if the file descriptor is locked by
+ * another thread:
+ */
+ if (_thread_fd_table[fd]->w_owner != NULL) {
+ /*
+ * Another thread has locked the file
+ * descriptor for write, so join the
+ * queue of threads waiting for a
+ * write lock on this file
+ * descriptor:
+ */
+ _thread_queue_enq(&_thread_fd_table[fd]->w_queue, _thread_run);
+
+ /*
+ * Save the file descriptor details
+ * in the thread structure for the
+ * running thread:
+ */
+ _thread_run->data.fd.fd = fd;
+ _thread_run->data.fd.branch = lineno;
+ _thread_run->data.fd.fname = fname;
+
+ /* Set the timeout: */
+ _thread_kern_set_timeout(timeout);
+
+ /*
+ * Schedule this thread to wait on
+ * the write lock. It will only be
+ * woken when it becomes the next in
+ * the queue and is granted access to
+ * the lock by the thread that is
+ * unlocking the file descriptor.
+ */
+ _thread_kern_sched_state(PS_FDLW_WAIT, __FILE__, __LINE__);
+
+ /*
+ * Block signals so that the file
+ * descriptor lock can again be
+ * tested:
+ */
+ _thread_kern_sig_block(NULL);
+ } else {
+ /*
+ * The running thread now owns the
+ * write lock on this file
+ * descriptor:
+ */
+ _thread_fd_table[fd]->w_owner = _thread_run;
+
+ /*
+ * Reset the number of write locks
+ * for this file descriptor:
+ */
+ _thread_fd_table[fd]->w_lockcount = 0;
+
+ /*
+ * Save the source file details for
+ * debugging:
+ */
+ _thread_fd_table[fd]->w_fname = fname;
+ _thread_fd_table[fd]->w_lineno = lineno;
+ }
+ }
+
+ /* Increment the write lock count: */
+ _thread_fd_table[fd]->w_lockcount++;
+ }
+ }
+
+ /* Unblock signals again: */
+ _thread_kern_sig_unblock(status);
+
+ /* Return the completion status: */
+ return (ret);
+}
+#endif
generated by cgit v1.2.3 (git 2.25.1) at 2025-10-31 11:37:24 +0000