1/* An fseeko() function that, together with fflush(), is POSIX compliant. 2 Copyright (C) 2007-2009 Free Software Foundation, Inc. 3 4 This program is free software; you can redistribute it and/or modify 5 it under the terms of the GNU General Public License as published by 6 the Free Software Foundation; either version 3, or (at your option) 7 any later version. 8 9 This program is distributed in the hope that it will be useful, 10 but WITHOUT ANY WARRANTY; without even the implied warranty of 11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 12 GNU General Public License for more details. 13 14 You should have received a copy of the GNU General Public License along 15 with this program; if not, write to the Free Software Foundation, 16 Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. */ 17 18#include <config.h> 19 20/* Specification. */ 21#include <stdio.h> 22 23/* Get off_t and lseek. */ 24#include <unistd.h> 25 26#include "stdio-impl.h" 27 28#undef fseeko 29#if !HAVE_FSEEKO 30# undef fseek 31# define fseeko fseek 32#endif 33 34int 35rpl_fseeko (FILE *fp, off_t offset, int whence) 36{ 37#if LSEEK_PIPE_BROKEN 38 /* mingw gives bogus answers rather than failure on non-seekable files. */ 39 if (lseek (fileno (fp), 0, SEEK_CUR) == -1) 40 return EOF; 41#endif 42 43 /* These tests are based on fpurge.c. */ 44#if defined _IO_ftrylockfile || __GNU_LIBRARY__ == 1 /* GNU libc, BeOS, Haiku, Linux libc5 */ 45 if (fp->_IO_read_end == fp->_IO_read_ptr 46 && fp->_IO_write_ptr == fp->_IO_write_base 47 && fp->_IO_save_base == NULL) 48#elif defined __sferror || defined __DragonFly__ /* FreeBSD, NetBSD, OpenBSD, DragonFly, MacOS X, Cygwin */ 49# if defined __SL64 && defined __SCLE /* Cygwin */ 50 if ((fp->_flags & __SL64) == 0) 51 { 52 /* Cygwin 1.5.0 through 1.5.24 failed to open stdin in 64-bit 53 mode; but has an fseeko that requires 64-bit mode. */ 54 FILE *tmp = fopen ("/dev/null", "r"); 55 if (!tmp) 56 return -1; 57 fp->_flags |= __SL64; 58 fp->_seek64 = tmp->_seek64; 59 fclose (tmp); 60 } 61# endif 62 if (fp_->_p == fp_->_bf._base 63 && fp_->_r == 0 64 && fp_->_w == ((fp_->_flags & (__SLBF | __SNBF | __SRD)) == 0 /* fully buffered and not currently reading? */ 65 ? fp_->_bf._size 66 : 0) 67 && fp_ub._base == NULL) 68#elif defined __EMX__ /* emx+gcc */ 69 if (fp->_ptr == fp->_buffer 70 && fp->_rcount == 0 71 && fp->_wcount == 0 72 && fp->_ungetc_count == 0) 73#elif defined _IOERR /* AIX, HP-UX, IRIX, OSF/1, Solaris, OpenServer, mingw */ 74 if (fp_->_ptr == fp_->_base 75 && (fp_->_ptr == NULL || fp_->_cnt == 0)) 76#elif defined __UCLIBC__ /* uClibc */ 77 if (((fp->__modeflags & __FLAG_WRITING) == 0 78 || fp->__bufpos == fp->__bufstart) 79 && ((fp->__modeflags & (__FLAG_READONLY | __FLAG_READING)) == 0 80 || fp->__bufpos == fp->__bufread)) 81#elif defined __QNX__ /* QNX */ 82 if ((fp->_Mode & 0x2000 /* _MWRITE */ ? fp->_Next == fp->_Buf : fp->_Next == fp->_Rend) 83 && fp->_Rback == fp->_Back + sizeof (fp->_Back) 84 && fp->_Rsave == NULL) 85#elif defined __MINT__ /* Atari FreeMiNT */ 86 if (fp->__bufp == fp->__buffer 87 && fp->__get_limit == fp->__bufp 88 && fp->__put_limit == fp->__bufp 89 && !fp->__pushed_back) 90#else 91 #error "Please port gnulib fseeko.c to your platform! Look at the code in fpurge.c, then report this to bug-gnulib." 92#endif 93 { 94 /* We get here when an fflush() call immediately preceded this one. We 95 know there are no buffers. 96 POSIX requires us to modify the file descriptor's position. 97 But we cannot position beyond end of file here. */ 98 off_t pos = 99 lseek (fileno (fp), 100 whence == SEEK_END && offset > 0 ? 0 : offset, 101 whence); 102 if (pos == -1) 103 { 104#if defined __sferror || defined __DragonFly__ /* FreeBSD, NetBSD, OpenBSD, DragonFly, MacOS X, Cygwin */ 105 fp_->_flags &= ~__SOFF; 106#endif 107 return -1; 108 } 109 110#if defined _IO_ftrylockfile || __GNU_LIBRARY__ == 1 /* GNU libc, BeOS, Haiku, Linux libc5 */ 111 fp->_flags &= ~_IO_EOF_SEEN; 112#elif defined __sferror || defined __DragonFly__ /* FreeBSD, NetBSD, OpenBSD, DragonFly, MacOS X, Cygwin */ 113 fp_->_offset = pos; 114 fp_->_flags |= __SOFF; 115 fp_->_flags &= ~__SEOF; 116#elif defined __EMX__ /* emx+gcc */ 117 fp->_flags &= ~_IOEOF; 118#elif defined _IOERR /* AIX, HP-UX, IRIX, OSF/1, Solaris, OpenServer, mingw */ 119 fp->_flag &= ~_IOEOF; 120#elif defined __MINT__ /* Atari FreeMiNT */ 121 fp->__offset = pos; 122 fp->__eof = 0; 123#endif 124 /* If we were not requested to position beyond end of file, we're 125 done. */ 126 if (!(whence == SEEK_END && offset > 0)) 127 return 0; 128 } 129 return fseeko (fp, offset, whence); 130} 131