freebsd-dev/lib/libc/stdio/findfp.c
Pedro F. Giffuni 8a16b7a18f General further adoption of SPDX licensing ID tags.
Mainly focus on files that use BSD 3-Clause license.

The Software Package Data Exchange (SPDX) group provides a specification
to make it easier for automated tools to detect and summarize well known
opensource licenses. We are gradually adopting the specification, noting
that the tags are considered only advisory and do not, in any way,
superceed or replace the license texts.

Special thanks to Wind River for providing access to "The Duke of
Highlander" tool: an older (2014) run over FreeBSD tree was useful as a
starting point.
2017-11-20 19:49:47 +00:00

222 lines
6.1 KiB
C

/*-
* SPDX-License-Identifier: BSD-3-Clause
*
* 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. 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("$FreeBSD$");
#include <sys/param.h>
#include <machine/atomic.h>
#include <unistd.h>
#include <stdio.h>
#include <stdlib.h>
#include <stdint.h>
#include <string.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) { \
._flags = (flags), \
._file = (file), \
._cookie = __sF + (file), \
._close = __sclose, \
._read = __sread, \
._seek = __sseek, \
._write = __swrite, \
._fl_mutex = PTHREAD_MUTEX_INITIALIZER, \
}
/* the usual - (stdin + stdout + stderr) */
static FILE usual[FOPEN_MAX - 3];
static struct glue uglue = { NULL, FOPEN_MAX - 3, usual };
static FILE __sF[3] = {
std(__SRD, STDIN_FILENO),
std(__SWR, STDOUT_FILENO),
std(__SWR|__SNBF, STDERR_FILENO)
};
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);
spinlock_t __stdio_thread_lock = _SPINLOCK_INITIALIZER;
#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(int n)
{
struct glue *g;
static FILE empty = { ._fl_mutex = PTHREAD_MUTEX_INITIALIZER };
FILE *p;
size_t align;
align = __alignof__(FILE);
g = (struct glue *)malloc(sizeof(*g) + align + n * sizeof(FILE));
if (g == NULL)
return (NULL);
p = (FILE *)roundup((uintptr_t)(g + 1), align);
g->next = NULL;
g->niobs = n;
g->iobs = p;
while (--n >= 0)
*p++ = empty;
return (g);
}
/*
* Find a free FILE for fopen et al.
*/
FILE *
__sfp(void)
{
FILE *fp;
int n;
struct glue *g;
if (!__sdidinit)
__sinit();
/*
* The list must be locked because a FILE may be updated.
*/
STDIO_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;
}
STDIO_THREAD_UNLOCK(); /* don't hold lock while malloc()ing. */
if ((g = moreglue(NDYNAMIC)) == NULL)
return (NULL);
STDIO_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 */
STDIO_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->_fl_mutex = NULL; */ /* once set always set (reused) */
fp->_orientation = 0;
memset(&fp->_mbstate, 0, sizeof(mbstate_t));
fp->_flags2 = 0;
return (fp);
}
/*
* 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(void);
void
f_prealloc(void)
{
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)) {
STDIO_THREAD_LOCK();
SET_GLUE_PTR(lastglue->next, g);
lastglue = g;
STDIO_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)
{
/* (void) _fwalk(fclose); */
(void) _fwalk(__sflush); /* `cheating' */
}
/*
* __sinit() is called whenever stdio's internal variables must be set up.
*/
void
__sinit(void)
{
/* Make sure we clean up on exit. */
__cleanup = _cleanup; /* conservative */
__sdidinit = 1;
}