diff options
Diffstat (limited to 'lib/libc/stdio/findfp.c')
| -rw-r--r-- | lib/libc/stdio/findfp.c | 245 |
1 files changed, 245 insertions, 0 deletions
diff --git a/lib/libc/stdio/findfp.c b/lib/libc/stdio/findfp.c new file mode 100644 index 0000000..73a0d4b --- /dev/null +++ b/lib/libc/stdio/findfp.c @@ -0,0 +1,245 @@ +/*- + * 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. + * 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("$FreeBSD$"); + +#include <sys/param.h> +#include <machine/atomic.h> +#include <unistd.h> +#include <stdio.h> +#include <stdlib.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) \ + {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 */ + /* the usual - (stdin + stdout + stderr) */ +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]; + +/* + * 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 because it is the only "old" system 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; + 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() +{ + FILE *fp; + int n; + struct glue *g; + + if (!__sdidinit) + __sinit(); + /* + * 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->orientation = 0; + memset(&fp->_extra->mbstate, 0, sizeof(mbstate_t)); + 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() +{ + 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; + } + THREAD_UNLOCK(); +} |
