11dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project/* $OpenBSD: freopen.c,v 1.9 2005/08/08 08:05:36 espie Exp $ */ 21dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project/*- 31dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * Copyright (c) 1990, 1993 41dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * The Regents of the University of California. All rights reserved. 51dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * 61dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * This code is derived from software contributed to Berkeley by 71dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * Chris Torek. 81dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * 91dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * Redistribution and use in source and binary forms, with or without 101dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * modification, are permitted provided that the following conditions 111dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * are met: 121dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * 1. Redistributions of source code must retain the above copyright 131dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * notice, this list of conditions and the following disclaimer. 141dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * 2. Redistributions in binary form must reproduce the above copyright 151dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * notice, this list of conditions and the following disclaimer in the 161dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * documentation and/or other materials provided with the distribution. 171dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * 3. Neither the name of the University nor the names of its contributors 181dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * may be used to endorse or promote products derived from this software 191dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * without specific prior written permission. 201dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * 211dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 221dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 231dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 241dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 251dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 261dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 271dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 281dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 291dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 301dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 311dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * SUCH DAMAGE. 321dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project */ 331dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 341dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project#include <sys/types.h> 351dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project#include <sys/stat.h> 361dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project#include <fcntl.h> 371dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project#include <errno.h> 381dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project#include <unistd.h> 391dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project#include <stdio.h> 401dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project#include <stdlib.h> 411dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project#include "local.h" 421dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 43a910abcd194830d2d113b3e183eb7df4d36cd92eAndré Goddard Rosa/* 44a910abcd194830d2d113b3e183eb7df4d36cd92eAndré Goddard Rosa * Re-direct an existing, open (probably) file to some other file. 451dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * ANSI is written such that the original file gets closed if at 461dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * all possible, no matter what. 471dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project */ 481dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source ProjectFILE * 491dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Projectfreopen(const char *file, const char *mode, FILE *fp) 501dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project{ 511dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project int f; 521dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project int flags, isopen, oflags, sverrno, wantfd; 531dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 541dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project if ((flags = __sflags(mode, &oflags)) == 0) { 551dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project (void) fclose(fp); 561dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project return (NULL); 571dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project } 581dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 591dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project if (!__sdidinit) 601dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project __sinit(); 611dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 62f582340a6a48588aa50da17e1620e8f91b146941Kenny Root FLOCKFILE(fp); 63f582340a6a48588aa50da17e1620e8f91b146941Kenny Root 641dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project /* 651dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * There are actually programs that depend on being able to "freopen" 661dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * descriptors that weren't originally open. Keep this from breaking. 671dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * Remember whether the stream was open to begin with, and which file 681dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * descriptor (if any) was associated with it. If it was attached to 691dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * a descriptor, defer closing it; freopen("/dev/stdin", "r", stdin) 701dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * should work. This is unnecessary if it was not a Unix file. 711dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project */ 721dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project if (fp->_flags == 0) { 731dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project fp->_flags = __SEOF; /* hold on to it */ 741dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project isopen = 0; 751dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project wantfd = -1; 761dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project } else { 771dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project /* flush the stream; ANSI doesn't require this. */ 781dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project if (fp->_flags & __SWR) 791dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project (void) __sflush(fp); 801dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project /* if close is NULL, closing is a no-op, hence pointless */ 811dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project isopen = fp->_close != NULL; 821dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project if ((wantfd = fp->_file) < 0 && isopen) { 831dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project (void) (*fp->_close)(fp->_cookie); 841dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project isopen = 0; 851dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project } 861dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project } 871dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 881dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project /* Get a new descriptor to refer to the new file. */ 891dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project f = open(file, oflags, DEFFILEMODE); 901dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project if (f < 0 && isopen) { 911dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project /* If out of fd's close the old one and try again. */ 921dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project if (errno == ENFILE || errno == EMFILE) { 931dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project (void) (*fp->_close)(fp->_cookie); 941dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project isopen = 0; 951dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project f = open(file, oflags, DEFFILEMODE); 961dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project } 971dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project } 981dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project sverrno = errno; 991dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 1001dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project /* 1011dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * Finish closing fp. Even if the open succeeded above, we cannot 1021dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * keep fp->_base: it may be the wrong size. This loses the effect 1031dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * of any setbuffer calls, but stdio has always done this before. 1041dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project */ 1051dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project if (isopen && f != wantfd) 1061dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project (void) (*fp->_close)(fp->_cookie); 1071dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project if (fp->_flags & __SMBF) 1081dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project free((char *)fp->_bf._base); 1091dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project fp->_w = 0; 1101dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project fp->_r = 0; 1111dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project fp->_p = NULL; 1121dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project fp->_bf._base = NULL; 1131dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project fp->_bf._size = 0; 1141dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project fp->_lbfsize = 0; 1151dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project if (HASUB(fp)) 1161dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project FREEUB(fp); 1171dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project _UB(fp)._size = 0; 1181dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project WCIO_FREE(fp); 1191dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project if (HASLB(fp)) 1201dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project FREELB(fp); 1211dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project fp->_lb._size = 0; 1221dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 1231dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project if (f < 0) { /* did not get it after all */ 1241dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project fp->_flags = 0; /* set it free */ 125f582340a6a48588aa50da17e1620e8f91b146941Kenny Root FUNLOCKFILE(fp); 1261dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project errno = sverrno; /* restore in case _close clobbered */ 1271dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project return (NULL); 1281dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project } 1291dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 1301dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project /* 1311dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * If reopening something that was open before on a real file, try 1321dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * to maintain the descriptor. Various C library routines (perror) 1331dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * assume stderr is always fd STDERR_FILENO, even if being freopen'd. 1341dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project */ 1351dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project if (wantfd >= 0 && f != wantfd) { 1361dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project if (dup2(f, wantfd) >= 0) { 1371dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project (void) close(f); 1381dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project f = wantfd; 1391dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project } 1401dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project } 1411dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 1421dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project fp->_flags = flags; 1431dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project fp->_file = f; 1441dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project fp->_cookie = fp; 1451dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project fp->_read = __sread; 1461dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project fp->_write = __swrite; 1471dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project fp->_seek = __sseek; 1481dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project fp->_close = __sclose; 1491dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 1501dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project /* 1511dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * When opening in append mode, even though we use O_APPEND, 1521dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * we need to seek to the end so that ftell() gets the right 1531dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * answer. If the user then alters the seek pointer, or 1541dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * the file extends, this will fail, but there is not much 1551dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * we can do about this. (We could set __SAPP and check in 1561dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * fseek and ftell.) 1571dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project */ 1581dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project if (oflags & O_APPEND) 1591dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project (void) __sseek((void *)fp, (fpos_t)0, SEEK_END); 160f582340a6a48588aa50da17e1620e8f91b146941Kenny Root FUNLOCKFILE(fp); 1611dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project return (fp); 1621dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project} 163