Fix the handle locking in stdio to use flockfile/funlockfile

internally when and where required.  Macros in <stdio.h> are updated
to automatically call the underlying functions when the process is
threaded to obtain the necessary locking.  A private mutex is added
to protect __sglue, the internal list of FILE handles, and another
to protect the one-time initialization.  Some routines in libc that
use getc() change to use getc_unlocked() as they're either protected
by their own lock or aren't thread-safe routines anyway.

committing on behalf of and okay guenther@ now that we have install
media space available.

1 files changed, 122 insertions, 131 deletions

diff --git a/lib/libpthread/uthread/uthread_file.c b/lib/libpthread/uthread/uthread_file.c
index d8c9cdcb818..25c2d0945cc 100644
--- a/lib/libpthread/uthread/uthread_file.c
+++ b/lib/libpthread/uthread/uthread_file.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: uthread_file.c,v 1.16 2009/10/22 01:23:16 guenther Exp $	*/
+/*	$OpenBSD: uthread_file.c,v 1.17 2009/11/09 00:18:27 kurt Exp $	*/
 /*
  * Copyright (c) 1995 John Birrell <jb@cimlogic.com.au>.
  * All rights reserved.
@@ -41,6 +41,7 @@
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
+#include <unistd.h>
 #include <sys/queue.h>
 #ifdef _THREAD_SAFE
 #include <pthread.h>
@@ -173,68 +174,65 @@ do_lock(int idx, FILE *fp)
 	return(p);
 }
 
+
 void
 flockfile(FILE * fp)
 {
 	int	idx = file_idx(fp);
 	struct	file_lock	*p;
 
-	/* Check if this is a real file: */
-	if (fileno(fp) >= 0) {
-		/* Lock the hash table: */
-		_SPINLOCK(&hash_lock);
+	/* 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));
+	/* 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;
-		}
+		/* 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);
+	/* 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);
+		/* 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 == _thread_run) {
 		/*
-		 * The file is already locked, so check if the
-		 * running thread is the owner:
+		 * The running thread is already the
+		 * owner, so increment the count of
+		 * the number of times it has locked
+		 * the file:
 		 */
-		} else if (p->owner == _thread_run) {
-			/*
-			 * The running thread is already the
-			 * owner, so increment the count of
-			 * the number of times it has locked
-			 * the file:
-			 */
-			p->count++;
+		p->count++;
 
-			/* Unlock the hash table: */
-			_SPINUNLOCK(&hash_lock);
-		} else {
-			/*
-			 * 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,_thread_run,qe);
+		/* Unlock the hash table: */
+		_SPINUNLOCK(&hash_lock);
+	} else {
+		/*
+		 * 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,_thread_run,qe);
 
-			/* Unlock the hash table: */
-			_SPINUNLOCK(&hash_lock);
+		/* Unlock the hash table: */
+		_SPINUNLOCK(&hash_lock);
 
-			/* Wait on the FILE lock: */
-			_thread_kern_sched_state(PS_FILE_WAIT, "", 0);
-		}
+		/* Wait on the FILE lock: */
+		_thread_kern_sched_state(PS_FILE_WAIT, "", 0);
 	}
-	return;
 }
 
 int
@@ -244,48 +242,45 @@ ftrylockfile(FILE * fp)
 	int	idx = file_idx(fp);
 	struct	file_lock	*p;
 
-	/* Check if this is a real file: */
-	if (fileno(fp) >= 0) {
-		/* Lock the hash table: */
-		_SPINLOCK(&hash_lock);
+	/* 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);
+	/* 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 == _thread_run) {
 		/*
-		 * The file is already locked, so check if the
-		 * running thread is the owner:
+		 * The running thread is already the
+		 * owner, so increment the count of
+		 * the number of times it has locked
+		 * the file:
 		 */
-		} else if (p->owner == _thread_run) {
-			/*
-			 * 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;
-		}
+		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;
+	/* Check if the lock was obtained: */
+	if (p != NULL)
+		/* Return success: */
+		ret = 0;
 
-		/* Unlock the hash table: */
-		_SPINUNLOCK(&hash_lock);
+	/* Unlock the hash table: */
+	_SPINUNLOCK(&hash_lock);
 
-	}
 	return (ret);
 }
 
@@ -295,68 +290,64 @@ funlockfile(FILE * fp)
 	int	idx = file_idx(fp);
 	struct	file_lock	*p;
 
-	/* Check if this is a real file: */
-	if (fileno(fp) >= 0) {
-		/*
-		 * Defer signals to protect the scheduling queues from
-		 * access by the signal handler:
-		 */
-		_thread_kern_sig_defer();
+	/*
+	 * Defer signals to protect the scheduling queues from
+	 * access by the signal handler:
+	 */
+	_thread_kern_sig_defer();
 
-		/* Lock the hash table: */
-		_SPINLOCK(&hash_lock);
+	/* 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 == _thread_run) {
 		/*
-		 * Get a pointer to the lock for the file and check that
-		 * the running thread is the one with the lock:
+		 * Check if this thread has locked the FILE
+		 * more than once:
 		 */
-		if ((p = find_lock(idx, fp)) != NULL &&
-		    p->owner == _thread_run) {
+		if (p->count > 1)
 			/*
-			 * Check if this thread has locked the FILE
-			 * more than once:
+			 * Decrement the count of the number of
+			 * times the running thread has locked this
+			 * file:
 			 */
-			if (p->count > 1)
-				/*
-				 * Decrement the count of the number of
-				 * times the running thread has locked this
-				 * file:
-				 */
-				p->count--;
-			else {
+			p->count--;
+		else {
+			/*
+			 * The running thread will release the
+			 * lock now:
+			 */
+			p->count = 0;
+
+			/* Get the new owner of the lock: */
+			if ((p->owner = TAILQ_FIRST(&p->l_head)) != NULL) {
+				/* Pop the thread off the queue: */
+				TAILQ_REMOVE(&p->l_head,p->owner,qe);
+
 				/*
-				 * The running thread will release the
-				 * lock now:
+				 * This is the first lock for the new
+				 * owner:
 				 */
-				p->count = 0;
-
-				/* Get the new owner of the lock: */
-				if ((p->owner = TAILQ_FIRST(&p->l_head)) != NULL) {
-					/* Pop the thread off the queue: */
-					TAILQ_REMOVE(&p->l_head,p->owner,qe);
-
-					/*
-					 * 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);
-				}
+				p->count = 1;
+
+				/* Allow the new owner to run: */
+				PTHREAD_NEW_STATE(p->owner,PS_RUNNING);
 			}
 		}
+	}
 
-		/* Unlock the hash table: */
-		_SPINUNLOCK(&hash_lock);
+	/* Unlock the hash table: */
+	_SPINUNLOCK(&hash_lock);
 
-		/*
-		 * Undefer and handle pending signals, yielding if
-		 * necessary:
-		 */
-		_thread_kern_sig_undefer();
-	}
-	return;
+	/*
+	 * Undefer and handle pending signals, yielding if
+	 * necessary:
+	 */
+	_thread_kern_sig_undefer();
 }
 
 #endif