/*- * 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(); }