1 /* Retrieve information about a FILE stream. 2 Copyright (C) 2007-2021 Free Software Foundation, Inc. 3 4 This file is free software: you can redistribute it and/or modify 5 it under the terms of the GNU Lesser General Public License as 6 published by the Free Software Foundation; either version 3 of the 7 License, or (at your option) any later version. 8 9 This file 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 Lesser General Public License for more details. 13 14 You should have received a copy of the GNU Lesser General Public License 15 along with this program. If not, see <https://www.gnu.org/licenses/>. */ 16 17 #include <config.h> 18 19 /* Specification. */ 20 #include "freadable.h" 21 22 #include "stdio-impl.h" 23 24 #if defined EPLAN9 /* Plan9 */ 25 # include <fcntl.h> 26 #endif 27 28 /* This file is not used on systems that have the __freadable function, 29 namely glibc >= 2.2, Solaris >= 7, UnixWare >= 7.1.4.MP4, Cygwin >= 1.7.34, 30 Android API >= 23, musl libc. */ 31 32 bool 33 freadable (FILE *fp) /* */ 34 { 35 /* Most systems provide FILE as a struct and the necessary bitmask in 36 <stdio.h>, because they need it for implementing getc() and putc() as 37 fast macros. */ 38 #if defined _IO_EOF_SEEN || defined _IO_ftrylockfile || __GNU_LIBRARY__ == 1 39 /* GNU libc, BeOS, Haiku, Linux libc5 */ 40 return (fp->_flags & _IO_NO_READS) == 0; 41 #elif defined __sferror || defined __DragonFly__ || defined __ANDROID__ 42 /* FreeBSD, NetBSD, OpenBSD, DragonFly, Mac OS X, Cygwin < 1.7.34, Minix 3, Android */ 43 return (fp_->_flags & (__SRW | __SRD)) != 0; 44 #elif defined __EMX__ /* emx+gcc */ 45 return (fp->_flags & (_IORW | _IOREAD)) != 0; 46 #elif defined __minix /* Minix */ 47 return (fp->_flags & _IOREAD) != 0; 48 #elif defined _IOERR /* AIX, HP-UX, IRIX, OSF/1, Solaris, OpenServer, UnixWare, mingw, MSVC, NonStop Kernel, OpenVMS */ 49 return (fp_->_flag & (_IORW | _IOREAD)) != 0; 50 #elif defined __QNX__ /* QNX */ 51 return (fp->_Mode & 0x1 /* _MOPENR */) != 0; 52 #elif defined __MINT__ /* Atari FreeMiNT */ 53 return fp->__mode.__read; 54 #elif defined EPLAN9 /* Plan9 */ 55 int fd = fp->fd; 56 if (fd >= 0) 57 { 58 int flags = fcntl (fd, F_GETFL, NULL); 59 if (flags >= 0) 60 { 61 flags &= O_ACCMODE; 62 return (flags == O_RDONLY || flags == O_RDWR); 63 } 64 } 65 return 0; 66 #else 67 # error "Please port gnulib freadable.c to your platform! Look at the definition of fopen, fdopen on your system, then report this to bug-gnulib." 68 #endif 69 }