Remove (int) file descriptor locking. It should be up to the

application to provide locking for I/O operations.  This doesn't
break any of my tests, but the old behavior can be restored by
compiling with _FDLOCKS_ENABLED.  This will eventually be removed
when it is obvious it does not cause any problems.

Remove most of flockfile implementation, with the exception of
flockfile_debug.

Make error messages more informational (submitted by Mike Heffner
<spock@techfour.net>, who's now known as mikeh@FreeBSD.org).

5 files changed, 51 insertions, 478 deletions

diff --git a/lib/libc_r/uthread/pthread_private.h b/lib/libc_r/uthread/pthread_private.h
index 78b75ef..7a37de8 100644
--- a/lib/libc_r/uthread/pthread_private.h
+++ b/lib/libc_r/uthread/pthread_private.h
@@ -1208,8 +1208,6 @@ void	_cond_wait_backout(pthread_t);
 void	_fd_lock_backout(pthread_t);
 int     _find_dead_thread(pthread_t);
 int     _find_thread(pthread_t);
-void	_flockfile_backout(pthread_t);
-void    _funlock_owned(pthread_t);
 struct pthread *_get_curthread(void);
 void	_set_curthread(struct pthread *);
 void	_join_backout(pthread_t);
@@ -1241,6 +1239,7 @@ int	_pthread_mutexattr_init(pthread_mutexattr_t *);
 int	_pthread_mutexattr_destroy(pthread_mutexattr_t *);
 int	_pthread_mutexattr_settype(pthread_mutexattr_t *, int);
 int	_pthread_once(pthread_once_t *, void (*) (void));
+pthread_t _pthread_self(void);
 int	_pthread_setspecific(pthread_key_t, const void *);
 void	_waitq_insert(pthread_t pthread);
 void	_waitq_remove(pthread_t pthread);
diff --git a/lib/libc_r/uthread/uthread_exit.c b/lib/libc_r/uthread/uthread_exit.c
index 169aa4f..fd0e84a 100644
--- a/lib/libc_r/uthread/uthread_exit.c
+++ b/lib/libc_r/uthread/uthread_exit.c
@@ -87,13 +87,9 @@ _thread_exit(char *fname, int lineno, char *string)
 	char            s[256];
 
 	/* Prepare an error message string: */
-	strcpy(s, "Fatal error '");
-	strcat(s, string);
-	strcat(s, "' at line ? ");
-	strcat(s, "in file ");
-	strcat(s, fname);
-	strcat(s, " (errno = ?");
-	strcat(s, ")\n");
+	snprintf(s, sizeof(s),
+	    "Fatal error '%s' at line %d in file %s (errno = %d)\n",
+	    string, lineno, fname, errno);
 
 	/* Write the string to the standard error file descriptor: */
 	__sys_write(2, s, strlen(s));
@@ -127,9 +123,6 @@ _thread_exit_cleanup(void)
 	/* Unlock all owned fd locks: */
 	_thread_fd_unlock_owned(curthread);
 
-	/* Unlock all owned file locks: */
-	_funlock_owned(curthread);
-
 	/* Unlock all private mutexes: */
 	_mutex_unlock_private(curthread);
 
diff --git a/lib/libc_r/uthread/uthread_fd.c b/lib/libc_r/uthread/uthread_fd.c
index ef905e3..98a70e0 100644
--- a/lib/libc_r/uthread/uthread_fd.c
+++ b/lib/libc_r/uthread/uthread_fd.c
@@ -58,8 +58,10 @@ do {							\
 static	spinlock_t	fd_table_lock	= _SPINLOCK_INITIALIZER;
 
 /* Prototypes: */
+#ifdef _FDLOCKS_ENABLED
 static inline pthread_t fd_next_reader(int fd);
 static inline pthread_t fd_next_writer(int fd);
+#endif
 
 
 /*
@@ -180,6 +182,7 @@ _thread_fd_table_init(int fd)
 	return (ret);
 }
 
+#ifdef _FDLOCKS_ENABLED
 void
 _thread_fd_unlock(int fd, int lock_type)
 {
@@ -991,3 +994,40 @@ fd_next_writer(int fd)
 
 	return (pthread);
 }
+
+#else
+
+void
+_thread_fd_unlock(int fd, int lock_type)
+{
+}
+
+int
+_thread_fd_lock(int fd, int lock_type, struct timespec * timeout)
+{
+	return (0);
+}
+
+void
+_thread_fd_unlock_debug(int fd, int lock_type, char *fname, int lineno)
+{
+}
+
+int
+_thread_fd_lock_debug(int fd, int lock_type, struct timespec * timeout,
+		char *fname, int lineno)
+{
+	return (0);
+}
+
+void
+_thread_fd_unlock_owned(pthread_t pthread)
+{
+}
+
+void
+_fd_lock_backout(pthread_t pthread)
+{
+}
+
+#endif
diff --git a/lib/libc_r/uthread/uthread_file.c b/lib/libc_r/uthread/uthread_file.c
index e5a8484..cbedbc7 100644
--- a/lib/libc_r/uthread/uthread_file.c
+++ b/lib/libc_r/uthread/uthread_file.c
@@ -1,5 +1,6 @@
 /*
  * Copyright (c) 1995 John Birrell <jb@cimlogic.com.au>.
+ * Copyright (c) 2001 Daniel Eischen <deischen@FreeBSD.org>
  * All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
@@ -37,472 +38,17 @@
  *
  */
 #include <stdio.h>
-#include <stdlib.h>
-#include <string.h>
-#include <sys/queue.h>
 #include <pthread.h>
 #include "pthread_private.h"
 
-/*
- * Weak symbols for externally visible functions in this file:
- */
-#pragma	weak	flockfile=_flockfile
-#pragma	weak	ftrylockfile=_ftrylockfile
-#pragma	weak	funlockfile=_funlockfile
-
-/*
- * The FILE lock structure. The FILE *fp is locked if the owner is
- * not NULL. If not locked, the file lock structure can be
- * reassigned to a different file by setting fp.
- */
-struct	file_lock {
-	LIST_ENTRY(file_lock)	entry;	/* Entry if file list.       */
-	TAILQ_HEAD(lock_head, pthread)
-				l_head;	/* Head of queue for threads */
-					/* waiting on this lock.     */
-	FILE		*fp;		/* The target file.          */
-	pthread_t	owner;		/* Thread that owns lock.    */
-	int		count;		/* Lock count for owner.     */
-};
-
-/*
- * The number of file lock lists into which the file pointer is
- * hashed. Ideally, the FILE structure size would have been increased,
- * but this causes incompatibility, so separate data structures are
- * required.
- */
-#define NUM_HEADS	128
-
-/*
- * This macro casts a file pointer to a long integer and right
- * shifts this by the number of bytes in a pointer. The shifted
- * value is then remaindered using the maximum number of hash
- * entries to produce and index into the array of static lock
- * structures. If there is a collision, a linear search of the
- * dynamic list of locks linked to each static lock is perfomed.
- */
-#define file_idx(_p)	((((u_long) _p) >> sizeof(void *)) % NUM_HEADS)
-
-/*
- * Global array of file locks. The first lock for each hash bucket is
- * allocated statically in the hope that there won't be too many
- * collisions that require a malloc and an element added to the list.
- */
-struct static_file_lock {
-	LIST_HEAD(file_list_head, file_lock) head;
-	struct	file_lock	fl;
-} flh[NUM_HEADS];
-
-/* Set to non-zero when initialisation is complete: */
-static	int	init_done	= 0;
-
-/* Lock for accesses to the hash table: */
-static	spinlock_t	hash_lock	= _SPINLOCK_INITIALIZER;
-
-/*
- * Find a lock structure for a FILE, return NULL if the file is
- * not locked:
- */
-static
-struct file_lock *
-find_lock(int idx, FILE *fp)
-{
-	struct file_lock *p;
-
-	/* Check if the file is locked using the static structure: */
-	if (flh[idx].fl.fp == fp && flh[idx].fl.owner != NULL)
-		/* Return a pointer to the static lock: */
-		p = &flh[idx].fl;
-	else {
-		/* Point to the first dynamic lock: */
-		p = LIST_FIRST(&flh[idx].head);
-
-		/*
-		 * Loop through the dynamic locks looking for the
-		 * target file:
-		 */
-		while (p != NULL && (p->fp != fp || p->owner == NULL))
-			/* Not this file, try the next: */
-			p = LIST_NEXT(p, entry);
-	}
-	return(p);
-}
-
-/*
- * Lock a file, assuming that there is no lock structure currently
- * assigned to it.
- */
-static
-struct file_lock *
-do_lock(int idx, FILE *fp)
-{
-	struct pthread	*curthread = _get_curthread();
-	struct file_lock *p;
-
-	/* Check if the static structure is not being used: */
-	if (flh[idx].fl.owner == NULL) {
-		/* Return a pointer to the static lock: */
-		p = &flh[idx].fl;
-	}
-	else {
-		/* Point to the first dynamic lock: */
-		p = LIST_FIRST(&flh[idx].head);
-
-		/*
-		 * Loop through the dynamic locks looking for a
-		 * lock structure that is not being used:
-		 */
-		while (p != NULL && p->owner != NULL)
-			/* This one is used, try the next: */
-			p = LIST_NEXT(p, entry);
-	}
-
-	/*
-	 * If an existing lock structure has not been found,
-	 * allocate memory for a new one:
-	 */
-	if (p == NULL && (p = (struct file_lock *)
-	    malloc(sizeof(struct file_lock))) != NULL) {
-		/* Add the new element to the list: */
-		LIST_INSERT_HEAD(&flh[idx].head, p, entry);
-	}
-
-	/* Check if there is a lock structure to acquire: */
-	if (p != NULL) {
-		/* Acquire the lock for the running thread: */
-		p->fp		= fp;
-		p->owner	= curthread;
-		p->count	= 1;
-		TAILQ_INIT(&p->l_head);
-	}
-	return(p);
-}
-
-void
-_flockfile_debug(FILE * fp, char *fname, int lineno)
-{
-	struct pthread	*curthread = _get_curthread();
-	int	idx = file_idx(fp);
-	struct	file_lock	*p;
-
-	/* Check if this is a real file: */
-	if (fp->_file >= 0) {
-		/* Lock the hash table: */
-		_SPINLOCK(&hash_lock);
-
-		/* Check if the static array has not been initialised: */
-		if (!init_done) {
-			/* Initialise the global array: */
-			memset(flh,0,sizeof(flh));
-
-			/* Flag the initialisation as complete: */
-			init_done = 1;
-		}
-
-		/* Get a pointer to any existing lock for the file: */
-		if ((p = find_lock(idx, fp)) == NULL) {
-			/*
-			 * The file is not locked, so this thread can
-			 * grab the lock:
-			 */
-			p = do_lock(idx, fp);
-
-			/* Unlock the hash table: */
-			_SPINUNLOCK(&hash_lock);
-
-		/*
-		 * The file is already locked, so check if the
-		 * running thread is the owner:
-		 */
-		} else if (p->owner == curthread) {
-			/*
-			 * The running thread is already the
-			 * owner, so increment the count of
-			 * the number of times it has locked
-			 * the file:
-			 */
-			p->count++;
-
-			/* Unlock the hash table: */
-			_SPINUNLOCK(&hash_lock);
-		} else {
-			/* Clear the interrupted flag: */
-			curthread->interrupted = 0;
-
-			/*
-			 * Prevent being context switched out while
-			 * adding this thread to the file lock queue.
-			 */
-			_thread_kern_sig_defer();
-
-			/*
-			 * The file is locked for another thread.
-			 * Append this thread to the queue of
-			 * threads waiting on the lock.
-			 */
-			TAILQ_INSERT_TAIL(&p->l_head,curthread,qe);
-			curthread->flags |= PTHREAD_FLAGS_IN_FILEQ;
-
-			/* Unlock the hash table: */
-			_SPINUNLOCK(&hash_lock);
-
-			curthread->data.fp = fp;
-
-			/* Wait on the FILE lock: */
-			_thread_kern_sched_state(PS_FILE_WAIT, fname, lineno);
-
-			if ((curthread->flags & PTHREAD_FLAGS_IN_FILEQ) != 0) {
-				TAILQ_REMOVE(&p->l_head,curthread,qe);
-				curthread->flags &= ~PTHREAD_FLAGS_IN_FILEQ;
-			}
-
-			_thread_kern_sig_undefer();
-
-			if (curthread->interrupted != 0 &&
-			    curthread->continuation != NULL)
-				curthread->continuation((void *)curthread);
-		}
-	}
-}
+extern void	_flockfile(FILE *);
 
 void
-_flockfile(FILE * fp)
-{
-	_flockfile_debug(fp, __FILE__, __LINE__);
-}
-
-int
-_ftrylockfile(FILE * fp)
-{
-	struct pthread	*curthread = _get_curthread();
-	int	ret = -1;
-	int	idx = file_idx(fp);
-	struct	file_lock	*p;
-
-	/* Check if this is a real file: */
-	if (fp->_file >= 0) {
-		/* Lock the hash table: */
-		_SPINLOCK(&hash_lock);
-
-		/* Get a pointer to any existing lock for the file: */
-		if ((p = find_lock(idx, fp)) == NULL) {
-			/*
-			 * The file is not locked, so this thread can
-			 * grab the lock:
-			 */
-			p = do_lock(idx, fp);
-
-		/*
-		 * The file is already locked, so check if the
-		 * running thread is the owner:
-		 */
-		} else if (p->owner == curthread) {
-			/*
-			 * The running thread is already the
-			 * owner, so increment the count of
-			 * the number of times it has locked
-			 * the file:
-			 */
-			p->count++;
-		} else {
-			/*
-			 * The file is locked for another thread,
-			 * so this try fails.
-			 */
-			p = NULL;
-		}
-
-		/* Check if the lock was obtained: */
-		if (p != NULL)
-			/* Return success: */
-			ret = 0;
-
-		/* Unlock the hash table: */
-		_SPINUNLOCK(&hash_lock);
-
-	}
-	return (ret);
-}
-
-void 
-_funlockfile(FILE * fp)
+_flockfile_debug(FILE *fp, char *fname, int lineno)
 {
-	struct pthread	*curthread = _get_curthread();
-	int	idx = file_idx(fp);
-	struct	file_lock	*p;
-
-	/* Check if this is a real file: */
-	if (fp->_file >= 0) {
-		/*
-		 * Defer signals to protect the scheduling queues from
-		 * access by the signal handler:
-		 */
-		_thread_kern_sig_defer();
-
-		/* Lock the hash table: */
-		_SPINLOCK(&hash_lock);
-
-		/*
-		 * Get a pointer to the lock for the file and check that
-		 * the running thread is the one with the lock:
-		 */
-		if ((p = find_lock(idx, fp)) != NULL &&
-		    p->owner == curthread) {
-			/*
-			 * Check if this thread has locked the FILE
-			 * more than once:
-			 */
-			if (p->count > 1)
-				/*
-				 * Decrement the count of the number of
-				 * times the running thread has locked this
-				 * file:
-				 */
-				p->count--;
-			else {
-				/*
-				 * The running thread will release the
-				 * lock now:
-				 */
-				p->count = 0;
-
-				/* Get the new owner of the lock: */
-				while ((p->owner = TAILQ_FIRST(&p->l_head)) != NULL) {
-					/* Pop the thread off the queue: */
-					TAILQ_REMOVE(&p->l_head,p->owner,qe);
-					p->owner->flags &= ~PTHREAD_FLAGS_IN_FILEQ;
-
-					if (p->owner->interrupted == 0) {
-						/*
-						 * This is the first lock for
-						 * the new owner:
-						 */
-						p->count = 1;
-
-						/* Allow the new owner to run: */
-						PTHREAD_NEW_STATE(p->owner,PS_RUNNING);
-
-						/* End the loop when we find a
-						 * thread that hasn't been
-						 * cancelled or interrupted;
-						 */
-						break;
-					}
-				}
-			}
-		}
-
-		/* Unlock the hash table: */
-		_SPINUNLOCK(&hash_lock);
+	pthread_t curthread = _pthread_self();
 
-		/*
-		 * Undefer and handle pending signals, yielding if
-		 * necessary:
-		 */
-		_thread_kern_sig_undefer();
-	}
+	curthread->lineno = lineno;
+	curthread->fname = fname;
+	_flockfile(fp);
 }
-
-void
-_funlock_owned(pthread_t pthread)
-{
-	int			idx;
-	struct file_lock	*p, *next_p;
-
-	/*
-	 * Defer signals to protect the scheduling queues from
-	 * access by the signal handler:
-	 */
-	_thread_kern_sig_defer();
-
-	/* Lock the hash table: */
-	_SPINLOCK(&hash_lock);
-
-	for (idx = 0; idx < NUM_HEADS; idx++) {
-		/* Check the static file lock first: */
-		p = &flh[idx].fl;
-		next_p = LIST_FIRST(&flh[idx].head);
-
-		while (p != NULL) {
-			if (p->owner == pthread) {
-				/*
-				 * The running thread will release the
-				 * lock now:
-				 */
-				p->count = 0;
-
-				/* Get the new owner of the lock: */
-				while ((p->owner = TAILQ_FIRST(&p->l_head)) != NULL) {
-					/* Pop the thread off the queue: */
-					TAILQ_REMOVE(&p->l_head,p->owner,qe);
-					p->owner->flags &= ~PTHREAD_FLAGS_IN_FILEQ;
-
-					if (p->owner->interrupted == 0) {
-						/*
-						 * This is the first lock for
-						 * the new owner:
-						 */
-						p->count = 1;
-
-						/* Allow the new owner to run: */
-						PTHREAD_NEW_STATE(p->owner,PS_RUNNING);
-
-						/* End the loop when we find a
-						 * thread that hasn't been
-						 * cancelled or interrupted;
-						 */
-						break;
-					}
-				}
-			}
-			p = next_p;
-			if (next_p != NULL)
-				next_p = LIST_NEXT(next_p, entry);
-		}
-	}
-
-	/* Unlock the hash table: */
-	_SPINUNLOCK(&hash_lock);
-
-	/*
-	 * Undefer and handle pending signals, yielding if
-	 * necessary:
-	 */
-	_thread_kern_sig_undefer();
-}
-
-void 
-_flockfile_backout(pthread_t pthread)
-{
-	int	idx = file_idx(pthread->data.fp);
-	struct	file_lock	*p;
-
-	/*
-	 * Defer signals to protect the scheduling queues from
-	 * access by the signal handler:
-	 */
-	_thread_kern_sig_defer();
-
-	/*
-	 * Get a pointer to the lock for the file and check that
-	 * the running thread is the one with the lock:
-	 */
-	if (((pthread->flags & PTHREAD_FLAGS_IN_FILEQ) != 0) &&
-	    ((p = find_lock(idx, pthread->data.fp)) != NULL)) {
-		/* Lock the hash table: */
-		_SPINLOCK(&hash_lock);
-
-		/* Remove the thread from the queue: */
-		TAILQ_REMOVE(&p->l_head, pthread, qe);
-		pthread->flags &= ~PTHREAD_FLAGS_IN_FILEQ;
-
-		/* Unlock the hash table: */
-		_SPINUNLOCK(&hash_lock);
-	}
-
-	/*
-	 * Undefer and handle pending signals, yielding if necessary:
-	 */
-	_thread_kern_sig_undefer();
-}
-
diff --git a/lib/libc_r/uthread/uthread_sig.c b/lib/libc_r/uthread/uthread_sig.c
index 9559bb7..a005adf 100644
--- a/lib/libc_r/uthread/uthread_sig.c
+++ b/lib/libc_r/uthread/uthread_sig.c
@@ -941,11 +941,6 @@ _thread_sig_wrapper(void)
 			psf->saved_state.psd_state = PS_RUNNING;
 			break;
 
-		case PS_FILE_WAIT:
-			_flockfile_backout(thread);
-			psf->saved_state.psd_state = PS_RUNNING;
-			break;
-
 		case PS_COND_WAIT:
 			_cond_wait_backout(thread);
 			psf->saved_state.psd_state = PS_RUNNING;