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Diffstat (limited to 'libc/stdio/findfp.c')
| -rw-r--r-- | libc/stdio/findfp.c | 181 |
1 files changed, 181 insertions, 0 deletions
diff --git a/libc/stdio/findfp.c b/libc/stdio/findfp.c new file mode 100644 index 0000000..a55a65d --- /dev/null +++ b/libc/stdio/findfp.c @@ -0,0 +1,181 @@ +/* $OpenBSD: findfp.c,v 1.9 2005/08/08 08:05:36 espie Exp $ */ +/*- + * 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. + */ + +#include <sys/param.h> +#include <unistd.h> +#include <stdio.h> +#include <errno.h> +#include <stdlib.h> +#include <string.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},0,__sF+file,__sclose,__sread,__sseek,__swrite, \ + {(unsigned char *)(__sFext+file), 0},NULL,0,{0,0,0},{0},{0,0},0,0} +/* p r w flags file _bf z cookie close read seek write + ext */ + + /* the usual - (stdin + stdout + stderr) */ +static FILE usual[FOPEN_MAX - 3]; +static struct __sfileext usualext[FOPEN_MAX - 3]; +static struct glue uglue = { 0, FOPEN_MAX - 3, usual }; + +struct __sfileext __sFext[3]; +FILE __sF[3] = { + std(__SRD, STDIN_FILENO), /* stdin */ + std(__SWR, STDOUT_FILENO), /* stdout */ + std(__SWR|__SNBF, STDERR_FILENO) /* stderr */ +}; +struct glue __sglue = { &uglue, 3, __sF }; + +static struct glue * +moreglue(int n) +{ + struct glue *g; + FILE *p; + struct __sfileext *pext; + static FILE empty; + char *data; + + data = malloc(sizeof(*g) + ALIGNBYTES + n * sizeof(FILE) + + n * sizeof(struct __sfileext)); + if (data == NULL) + return (NULL); + g = (struct glue *)data; + p = (FILE *)ALIGN(data + sizeof(*g)); + pext = (struct __sfileext *) + (ALIGN(data + sizeof(*g)) + n * sizeof(FILE)); + g->next = NULL; + g->niobs = n; + g->iobs = p; + while (--n >= 0) { + *p = empty; + _FILEEXT_SETUP(p, pext); + p++; + pext++; + } + return (g); +} + +/* + * Find a free FILE for fopen et al. + */ +FILE * +__sfp(void) +{ + FILE *fp; + int n; + struct glue *g; + + if (!__sdidinit) + __sinit(); + for (g = &__sglue;; g = g->next) { + for (fp = g->iobs, n = g->niobs; --n >= 0; fp++) + if (fp->_flags == 0) + goto found; + if (g->next == NULL && (g->next = moreglue(NDYNAMIC)) == NULL) + break; + } + return (NULL); +found: + fp->_flags = 1; /* reserve this slot; caller sets real flags */ + 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->_lb._base = NULL; /* no line buffer */ + fp->_lb._size = 0; + _FILEEXT_INIT(fp); + return (fp); +} + +#if 0 +#define getdtablesize() sysconf(_SC_OPEN_MAX) + +/* + * XXX. Force immediate allocation of internal memory. Not used by stdio, + * but documented historically for certain applications. Bad applications. + */ +void +f_prealloc(void) +{ + struct glue *g; + int n; + + n = getdtablesize() - FOPEN_MAX + 20; /* 20 for slop. */ + for (g = &__sglue; (n -= g->niobs) > 0 && g->next; g = g->next) + /* void */; + if (n > 0) + g->next = moreglue(n); +} +#endif + +/* + * exit() and abort() call _cleanup() through the callback registered + * with __atexit_register_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) +{ + int i; + + for (i = 0; i < FOPEN_MAX - 3; i++) { + _FILEEXT_SETUP(usual+i, usualext+i); + } + /* make sure we clean up on exit */ + __atexit_register_cleanup(_cleanup); /* conservative */ + __sdidinit = 1; +} |