[apple/libc.git] / stdio / findfp-fbsd.c

/*-
 * Copyright (c) 1990, 1993
 *	The Regents of the University of California.  All rights reserved.
 *
 * This code is derived from software contributed to Berkeley by
 * Chris Torek.
 *
 * 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 the University of
 *	California, Berkeley and its contributors.
 * 4. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS 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.
 */

#if defined(LIBC_SCCS) && !defined(lint)
static char sccsid[] = "@(#)findfp.c	8.2 (Berkeley) 1/4/94";
#endif /* LIBC_SCCS and not lint */
#include <sys/cdefs.h>
__FBSDID("$FreeBSD: src/lib/libc/stdio/findfp.c,v 1.29 2004/05/22 15:19:41 tjr Exp $");

#include <sys/param.h>
#include <machine/atomic.h>
#include <unistd.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <libkern/OSAtomic.h>
#include <errno.h>

#include <pthread.h>
#include <spinlock.h>

#include "libc_private.h"
#include "local.h"
#include "glue.h"

int	__sdidinit;

#define	NDYNAMIC 10		/* add ten more whenever necessary */

#define	std(flags, file) \
  	{0,0,0,flags,file,{0},0,__sF+file,__sclose,__sread,__sseek,__swrite, \
	 {0}, __sFX + file}
  /*	 p r w flags file _bf z  cookie      close    read    seek    write */
  /*     _ub _extra */
#define	__sFXInit	{0, PTHREAD_MUTEX_INITIALIZER}
  /* set counted */
#define	__sFXInit3	{0, PTHREAD_MUTEX_INITIALIZER, 0, 0, 0, 1}
				/* the usual - (stdin + stdout + stderr) */

static int __scounted;		/* streams counted against STREAM_MAX */
static int __stream_max;

static FILE usual[FOPEN_MAX - 3];
static struct __sFILEX usual_extra[FOPEN_MAX - 3];
static struct glue uglue = { NULL, FOPEN_MAX - 3, usual };

static struct __sFILEX __sFX[3] = {__sFXInit3, __sFXInit3, __sFXInit3};

/*
 * We can't make this 'static' until 6.0-current due to binary
 * compatibility concerns.  This also means we cannot change the
 * sizeof(FILE) until that time either and must continue to use the
 * __sFILEX stuff to add to FILE.
 */
FILE __sF[3] = {
	std(__SRD, STDIN_FILENO),
	std(__SWR, STDOUT_FILENO),
	std(__SWR|__SNBF, STDERR_FILENO)
};

/*
 * The following kludge is done to ensure enough binary compatibility
 * with future versions of libc.  Or rather it allows us to work with
 * libraries that have been built with a newer libc that defines these
 * symbols and expects libc to provide them.  We only have need to support
 * i386 and alpha because they are the only "old" systems we have deployed.
 */
FILE *__stdinp = &__sF[0];
FILE *__stdoutp = &__sF[1];
FILE *__stderrp = &__sF[2];

struct glue __sglue = { &uglue, 3, __sF };
static struct glue *lastglue = &uglue;

static struct glue *	moreglue(int);

static spinlock_t thread_lock = _SPINLOCK_INITIALIZER;
#define THREAD_LOCK()	if (__isthreaded) _SPINLOCK(&thread_lock)
#define THREAD_UNLOCK()	if (__isthreaded) _SPINUNLOCK(&thread_lock)

#if NOT_YET
#define	SET_GLUE_PTR(ptr, val)	atomic_set_rel_ptr(&(ptr), (uintptr_t)(val))
#else
#define	SET_GLUE_PTR(ptr, val)	ptr = val
#endif

static struct glue *
moreglue(n)
	int n;
{
	struct glue *g;
	static FILE empty;
	static struct __sFILEX emptyx = __sFXInit;
	FILE *p;
	struct __sFILEX *fx;

	g = (struct glue *)malloc(sizeof(*g) + ALIGNBYTES + n * sizeof(FILE) +
	    n * sizeof(struct __sFILEX));
	if (g == NULL)
		return (NULL);
	p = (FILE *)ALIGN(g + 1);
	fx = (struct __sFILEX *)&p[n];
	g->next = NULL;
	g->niobs = n;
	g->iobs = p;
	while (--n >= 0) {
		*p = empty;
		p->_extra = fx;
		*p->_extra = emptyx;
		p++, fx++;
	}
	return (g);
}

/*
 * Find a free FILE for fopen et al.
 */
FILE *
__sfp(int count)
{
	FILE	*fp;
	int	n;
	struct glue *g;

	if (!__sdidinit)
		__sinit();

	if (count) {
		if (__scounted >= __stream_max) {
			THREAD_UNLOCK();
			errno = EMFILE;
			return NULL;
		}
		OSAtomicIncrement32(&__scounted);
	}
	/*
	 * The list must be locked because a FILE may be updated.
	 */
	THREAD_LOCK();
	for (g = &__sglue; g != NULL; g = g->next) {
		for (fp = g->iobs, n = g->niobs; --n >= 0; fp++)
			if (fp->_flags == 0)
				goto found;
	}
	THREAD_UNLOCK();	/* don't hold lock while malloc()ing. */
	if ((g = moreglue(NDYNAMIC)) == NULL)
		return (NULL);
	THREAD_LOCK();		/* reacquire the lock */
	SET_GLUE_PTR(lastglue->next, g); /* atomically append glue to list */
	lastglue = g;		/* not atomic; only accessed when locked */
	fp = g->iobs;
found:
	fp->_flags = 1;		/* reserve this slot; caller sets real flags */
	THREAD_UNLOCK();
	fp->_p = NULL;		/* no current pointer */
	fp->_w = 0;		/* nothing to read or write */
	fp->_r = 0;
	fp->_bf._base = NULL;	/* no buffer */
	fp->_bf._size = 0;
	fp->_lbfsize = 0;	/* not line buffered */
	fp->_file = -1;		/* no file */
/*	fp->_cookie = <any>; */	/* caller sets cookie, _read/_write etc */
	fp->_ub._base = NULL;	/* no ungetc buffer */
	fp->_ub._size = 0;
	fp->_lb._base = NULL;	/* no line buffer */
	fp->_lb._size = 0;
/*	fp->_lock = NULL; */	/* once set always set (reused) */
	fp->_extra->fl_mutex = (pthread_mutex_t)PTHREAD_MUTEX_INITIALIZER;
	fp->_extra->orientation = 0;
	fp->_extra->counted = count ? 1 : 0;
	memset(&fp->_extra->mbstate, 0, sizeof(mbstate_t));
	return (fp);
}

/*
 * Mark as free and update count as needed
 */
__private_extern__ void
__sfprelease(FILE *fp)
{
	if (fp->_extra->counted) {
		OSAtomicDecrement32(&__scounted);
		fp->_extra->counted = 0;
	}
	fp->_flags = 0;
}

/*
 * XXX.  Force immediate allocation of internal memory.  Not used by stdio,
 * but documented historically for certain applications.  Bad applications.
 */
__warn_references(f_prealloc, 
	"warning: this program uses f_prealloc(), which is not recommended.");

void
f_prealloc()
{
	struct glue *g;
	int n;

	n = getdtablesize() - FOPEN_MAX + 20;		/* 20 for slop. */
	/*
	 * It should be safe to walk the list without locking it;
	 * new nodes are only added to the end and none are ever
	 * removed.
	 */
	for (g = &__sglue; (n -= g->niobs) > 0 && g->next; g = g->next)
		/* void */;
	if ((n > 0) && ((g = moreglue(n)) != NULL)) {
		THREAD_LOCK();
		SET_GLUE_PTR(lastglue->next, g);
		lastglue = g;
		THREAD_UNLOCK();
	}
}

/*
 * exit() calls _cleanup() through *__cleanup, set whenever we
 * open or buffer a file.  This chicanery is done so that programs
 * that do not use stdio need not link it all in.
 *
 * The name `_cleanup' is, alas, fairly well known outside stdio.
 */
void
_cleanup()
{
	/* (void) _fwalk(fclose); */
	(void) _fwalk(__sflush);		/* `cheating' */
}

/*
 * __sinit() is called whenever stdio's internal variables must be set up.
 */
void
__sinit()
{
	int	i;

	THREAD_LOCK();
	if (__sdidinit == 0) {
		/* Set _extra for the usual suspects. */
		for (i = 0; i < FOPEN_MAX - 3; i++)
			usual[i]._extra = &usual_extra[i];

		/* Make sure we clean up on exit. */
		__cleanup = _cleanup;		/* conservative */
		__sdidinit = 1;
		__stream_max = sysconf(_SC_STREAM_MAX);
		__scounted = 3;			/* std{in,out,err} already exists */
	}
	THREAD_UNLOCK();
}
Commit	Line	Data
224c7076 A	1	/*-
	2	* Copyright (c) 1990, 1993
	3	* The Regents of the University of California. All rights reserved.
	4	*
	5	* This code is derived from software contributed to Berkeley by
	6	* Chris Torek.
	7	*
	8	* Redistribution and use in source and binary forms, with or without
	9	* modification, are permitted provided that the following conditions
	10	* are met:
	11	* 1. Redistributions of source code must retain the above copyright
	12	* notice, this list of conditions and the following disclaimer.
	13	* 2. Redistributions in binary form must reproduce the above copyright
	14	* notice, this list of conditions and the following disclaimer in the
	15	* documentation and/or other materials provided with the distribution.
	16	* 3. All advertising materials mentioning features or use of this software
	17	* must display the following acknowledgement:
	18	* This product includes software developed by the University of
	19	* California, Berkeley and its contributors.
	20	* 4. Neither the name of the University nor the names of its contributors
	21	* may be used to endorse or promote products derived from this software
	22	* without specific prior written permission.
	23	*
	24	* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
	25	* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
	26	* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
	27	* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
	28	* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
	29	* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
	30	* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
	31	* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
	32	* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
	33	* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
	34	* SUCH DAMAGE.
	35	*/
	36
	37	#if defined(LIBC_SCCS) && !defined(lint)
	38	static char sccsid[] = "@(#)findfp.c 8.2 (Berkeley) 1/4/94";
	39	#endif /* LIBC_SCCS and not lint */
	40	#include <sys/cdefs.h>
	41	__FBSDID("$FreeBSD: src/lib/libc/stdio/findfp.c,v 1.29 2004/05/22 15:19:41 tjr Exp $");
	42
	43	#include <sys/param.h>
	44	#include <machine/atomic.h>
	45	#include <unistd.h>
	46	#include <stdio.h>
	47	#include <stdlib.h>
	48	#include <string.h>
34e8f829 A	49	#include <libkern/OSAtomic.h>
34e8f829 A	50	#include <errno.h>
224c7076 A	51
	52	#include <pthread.h>
	53	#include <spinlock.h>
	54
	55	#include "libc_private.h"
	56	#include "local.h"
	57	#include "glue.h"
	58
	59	int __sdidinit;
	60
	61	#define NDYNAMIC 10 /* add ten more whenever necessary */
	62
	63	#define std(flags, file) \
	64	{0,0,0,flags,file,{0},0,__sF+file,__sclose,__sread,__sseek,__swrite, \
	65	{0}, __sFX + file}
	66	/* p r w flags file _bf z cookie close read seek write */
	67	/* _ub _extra */
	68	#define __sFXInit {0, PTHREAD_MUTEX_INITIALIZER}
34e8f829 A	69	/* set counted */
34e8f829 A	70	#define __sFXInit3 {0, PTHREAD_MUTEX_INITIALIZER, 0, 0, 0, 1}
224c7076	71	/* the usual - (stdin + stdout + stderr) */
34e8f829 A	72
	73	static int __scounted; /* streams counted against STREAM_MAX */
	74	static int __stream_max;
	75
224c7076 A	76	static FILE usual[FOPEN_MAX - 3];
	77	static struct __sFILEX usual_extra[FOPEN_MAX - 3];
	78	static struct glue uglue = { NULL, FOPEN_MAX - 3, usual };
	79
34e8f829	80	static struct __sFILEX __sFX[3] = {__sFXInit3, __sFXInit3, __sFXInit3};
224c7076 A	81
	82	/*
	83	* We can't make this 'static' until 6.0-current due to binary
	84	* compatibility concerns. This also means we cannot change the
	85	* sizeof(FILE) until that time either and must continue to use the
	86	* __sFILEX stuff to add to FILE.
	87	*/
	88	FILE __sF[3] = {
	89	std(__SRD, STDIN_FILENO),
	90	std(__SWR, STDOUT_FILENO),
	91	std(__SWR\|__SNBF, STDERR_FILENO)
	92	};
	93
	94	/*
	95	* The following kludge is done to ensure enough binary compatibility
	96	* with future versions of libc. Or rather it allows us to work with
	97	* libraries that have been built with a newer libc that defines these
	98	* symbols and expects libc to provide them. We only have need to support
	99	* i386 and alpha because they are the only "old" systems we have deployed.
	100	*/
	101	FILE *__stdinp = &__sF[0];
	102	FILE *__stdoutp = &__sF[1];
	103	FILE *__stderrp = &__sF[2];
	104
	105	struct glue __sglue = { &uglue, 3, __sF };
	106	static struct glue *lastglue = &uglue;
	107
	108	static struct glue * moreglue(int);
	109
	110	static spinlock_t thread_lock = _SPINLOCK_INITIALIZER;
	111	#define THREAD_LOCK() if (__isthreaded) _SPINLOCK(&thread_lock)
	112	#define THREAD_UNLOCK() if (__isthreaded) _SPINUNLOCK(&thread_lock)
	113
	114	#if NOT_YET
	115	#define SET_GLUE_PTR(ptr, val) atomic_set_rel_ptr(&(ptr), (uintptr_t)(val))
	116	#else
	117	#define SET_GLUE_PTR(ptr, val) ptr = val
	118	#endif
	119
	120	static struct glue *
	121	moreglue(n)
	122	int n;
	123	{
	124	struct glue *g;
	125	static FILE empty;
	126	static struct __sFILEX emptyx = __sFXInit;
	127	FILE *p;
	128	struct __sFILEX *fx;
	129
	130	g = (struct glue )malloc(sizeof(g) + ALIGNBYTES + n * sizeof(FILE) +
	131	n * sizeof(struct __sFILEX));
	132	if (g == NULL)
	133	return (NULL);
	134	p = (FILE *)ALIGN(g + 1);
	135	fx = (struct __sFILEX *)&p[n];
	136	g->next = NULL;
	137	g->niobs = n;
	138	g->iobs = p;
	139	while (--n >= 0) {
	140	*p = empty;
	141	p->_extra = fx;
	142	*p->_extra = emptyx;
	143	p++, fx++;
	144	}
145	return (g);
146	}
147
148	/*
149	* Find a free FILE for fopen et al.
150	*/
151	FILE *
34e8f829	152	__sfp(int count)
224c7076 A	153	{
	154	FILE *fp;
	155	int n;
	156	struct glue *g;
	157
	158	if (!__sdidinit)
	159	__sinit();
34e8f829 A	160
	161	if (count) {
	162	if (__scounted >= __stream_max) {
	163	THREAD_UNLOCK();
	164	errno = EMFILE;
	165	return NULL;
	166	}
	167	OSAtomicIncrement32(&__scounted);
	168	}
224c7076 A	169	/*
	170	* The list must be locked because a FILE may be updated.
	171	*/
	172	THREAD_LOCK();
	173	for (g = &__sglue; g != NULL; g = g->next) {
	174	for (fp = g->iobs, n = g->niobs; --n >= 0; fp++)
	175	if (fp->_flags == 0)
	176	goto found;
	177	}
	178	THREAD_UNLOCK(); /* don't hold lock while malloc()ing. */
	179	if ((g = moreglue(NDYNAMIC)) == NULL)
	180	return (NULL);
	181	THREAD_LOCK(); /* reacquire the lock */
	182	SET_GLUE_PTR(lastglue->next, g); /* atomically append glue to list */
	183	lastglue = g; /* not atomic; only accessed when locked */
	184	fp = g->iobs;
	185	found:
	186	fp->_flags = 1; /* reserve this slot; caller sets real flags */
	187	THREAD_UNLOCK();
	188	fp->_p = NULL; /* no current pointer */
	189	fp->_w = 0; /* nothing to read or write */
	190	fp->_r = 0;
	191	fp->_bf._base = NULL; /* no buffer */
	192	fp->_bf._size = 0;
	193	fp->_lbfsize = 0; /* not line buffered */
	194	fp->_file = -1; /* no file */
	195	/* fp->_cookie = <any>; / / caller sets cookie, _read/_write etc */
	196	fp->_ub._base = NULL; /* no ungetc buffer */
	197	fp->_ub._size = 0;
	198	fp->_lb._base = NULL; /* no line buffer */
	199	fp->_lb._size = 0;
	200	/* fp->_lock = NULL; / / once set always set (reused) */
	201	fp->_extra->fl_mutex = (pthread_mutex_t)PTHREAD_MUTEX_INITIALIZER;
	202	fp->_extra->orientation = 0;
34e8f829	203	fp->_extra->counted = count ? 1 : 0;
224c7076 A	204	memset(&fp->_extra->mbstate, 0, sizeof(mbstate_t));
	205	return (fp);
	206	}
	207
34e8f829 A	208	/*
	209	* Mark as free and update count as needed
	210	*/
	211	__private_extern__ void
	212	__sfprelease(FILE *fp)
	213	{
	214	if (fp->_extra->counted) {
	215	OSAtomicDecrement32(&__scounted);
	216	fp->_extra->counted = 0;
	217	}
	218	fp->_flags = 0;
	219	}
	220
224c7076 A	221	/*
	222	* XXX. Force immediate allocation of internal memory. Not used by stdio,
	223	* but documented historically for certain applications. Bad applications.
	224	*/
	225	__warn_references(f_prealloc,
	226	"warning: this program uses f_prealloc(), which is not recommended.");
	227
	228	void
	229	f_prealloc()
	230	{
	231	struct glue *g;
	232	int n;
	233
	234	n = getdtablesize() - FOPEN_MAX + 20; /* 20 for slop. */
	235	/*
	236	* It should be safe to walk the list without locking it;
	237	* new nodes are only added to the end and none are ever
	238	* removed.
	239	*/
	240	for (g = &__sglue; (n -= g->niobs) > 0 && g->next; g = g->next)
	241	/* void */;
	242	if ((n > 0) && ((g = moreglue(n)) != NULL)) {
	243	THREAD_LOCK();
	244	SET_GLUE_PTR(lastglue->next, g);
	245	lastglue = g;
	246	THREAD_UNLOCK();
	247	}
	248	}
	249
	250	/*
	251	* exit() calls _cleanup() through *__cleanup, set whenever we
	252	* open or buffer a file. This chicanery is done so that programs
	253	* that do not use stdio need not link it all in.
	254	*
	255	* The name `_cleanup' is, alas, fairly well known outside stdio.
	256	*/
	257	void
	258	_cleanup()
	259	{
	260	/* (void) _fwalk(fclose); */
	261	(void) _fwalk(__sflush); /* `cheating' */
	262	}
	263
	264	/*
	265	* __sinit() is called whenever stdio's internal variables must be set up.
	266	*/
	267	void
	268	__sinit()
	269	{
	270	int i;
	271
	272	THREAD_LOCK();
	273	if (__sdidinit == 0) {
	274	/* Set _extra for the usual suspects. */
	275	for (i = 0; i < FOPEN_MAX - 3; i++)
	276	usual[i]._extra = &usual_extra[i];
	277
	278	/* Make sure we clean up on exit. */
	279	__cleanup = _cleanup; /* conservative */
	280	__sdidinit = 1;
34e8f829 A	281	__stream_max = sysconf(_SC_STREAM_MAX);
34e8f829 A	282	__scounted = 3; /* std{in,out,err} already exists */
224c7076 A	283	}
	284	THREAD_UNLOCK();
	285	}