diff options
Diffstat (limited to 'lib/libc/stdio/findfp.c')
| -rw-r--r-- | lib/libc/stdio/findfp.c | 217 |
1 files changed, 217 insertions, 0 deletions
diff --git a/lib/libc/stdio/findfp.c b/lib/libc/stdio/findfp.c new file mode 100644 index 0000000..89c0536 --- /dev/null +++ b/lib/libc/stdio/findfp.c @@ -0,0 +1,217 @@ +/*- + * 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) { \ + ._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); + +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 = { ._fl_mutex = PTHREAD_MUTEX_INITIALIZER }; + FILE *p; + + g = (struct glue *)malloc(sizeof(*g) + ALIGNBYTES + n * sizeof(FILE)); + if (g == NULL) + return (NULL); + p = (FILE *)ALIGN(g + 1); + 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() +{ + 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->_fl_mutex = NULL; */ /* once set always set (reused) */ + fp->_orientation = 0; + memset(&fp->_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(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)) { + 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() +{ + + /* Make sure we clean up on exit. */ + __cleanup = _cleanup; /* conservative */ + __sdidinit = 1; +} |
