1 /* Duplicate an open file descriptor to a specified file descriptor. 2 3 Copyright (C) 1999, 2004-2007, 2009-2012 Free Software Foundation, Inc. 4 5 This program is free software: you can redistribute it and/or modify 6 it under the terms of the GNU General Public License as published by 7 the Free Software Foundation; either version 3 of the License, or 8 (at your option) any later version. 9 10 This program is distributed in the hope that it will be useful, 11 but WITHOUT ANY WARRANTY; without even the implied warranty of 12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 13 GNU General Public License for more details. 14 15 You should have received a copy of the GNU General Public License 16 along with this program. If not, see <http://www.gnu.org/licenses/>. */ 17 18 /* written by Paul Eggert */ 19 20 #include <config.h> 21 22 /* Specification. */ 23 #include <unistd.h> 24 25 #include <errno.h> 26 #include <fcntl.h> 27 28 #if HAVE_DUP2 29 30 # undef dup2 31 32 # if (defined _WIN32 || defined __WIN32__) && ! defined __CYGWIN__ 33 34 /* Get declarations of the native Windows API functions. */ 35 # define WIN32_LEAN_AND_MEAN 36 # include <windows.h> 37 38 # include "msvc-inval.h" 39 40 /* Get _get_osfhandle. */ 41 # include "msvc-nothrow.h" 42 43 static int 44 ms_windows_dup2 (int fd, int desired_fd) 45 { 46 int result; 47 48 /* If fd is closed, mingw hangs on dup2 (fd, fd). If fd is open, 49 dup2 (fd, fd) returns 0, but all further attempts to use fd in 50 future dup2 calls will hang. */ 51 if (fd == desired_fd) 52 { 53 if ((HANDLE) _get_osfhandle (fd) == INVALID_HANDLE_VALUE) 54 { 55 errno = EBADF; 56 return -1; 57 } 58 return fd; 59 } 60 61 /* Wine 1.0.1 return 0 when desired_fd is negative but not -1: 62 http://bugs.winehq.org/show_bug.cgi?id=21289 */ 63 if (desired_fd < 0) 64 { 65 errno = EBADF; 66 return -1; 67 } 68 69 TRY_MSVC_INVAL 70 { 71 result = dup2 (fd, desired_fd); 72 } 73 CATCH_MSVC_INVAL 74 { 75 errno = EBADF; 76 result = -1; 77 } 78 DONE_MSVC_INVAL; 79 80 if (result == 0) 81 result = desired_fd; 82 83 return result; 84 } 85 86 # define dup2 ms_windows_dup2 87 88 # endif 89 90 int 91 rpl_dup2 (int fd, int desired_fd) 92 { 93 int result; 94 95 # ifdef F_GETFL 96 /* On Linux kernels 2.6.26-2.6.29, dup2 (fd, fd) returns -EBADF. 97 On Cygwin 1.5.x, dup2 (1, 1) returns 0. 98 On Haiku, dup2 (fd, fd) mistakenly clears FD_CLOEXEC. */ 99 if (fd == desired_fd) 100 return fcntl (fd, F_GETFL) == -1 ? -1 : fd; 101 # endif 102 103 result = dup2 (fd, desired_fd); 104 105 /* Correct an errno value on FreeBSD 6.1 and Cygwin 1.5.x. */ 106 if (result == -1 && errno == EMFILE) 107 errno = EBADF; 108 # if REPLACE_FCHDIR 109 if (fd != desired_fd && result != -1) 110 result = _gl_register_dup (fd, result); 111 # endif 112 return result; 113 } 114 115 #else /* !HAVE_DUP2 */ 116 117 /* On older platforms, dup2 did not exist. */ 118 119 # ifndef F_DUPFD 120 static int 121 dupfd (int fd, int desired_fd) 122 { 123 int duplicated_fd = dup (fd); 124 if (duplicated_fd < 0 || duplicated_fd == desired_fd) 125 return duplicated_fd; 126 else 127 { 128 int r = dupfd (fd, desired_fd); 129 int e = errno; 130 close (duplicated_fd); 131 errno = e; 132 return r; 133 } 134 } 135 # endif 136 137 int 138 dup2 (int fd, int desired_fd) 139 { 140 int result = fcntl (fd, F_GETFL) < 0 ? -1 : fd; 141 if (result == -1 || fd == desired_fd) 142 return result; 143 close (desired_fd); 144 # ifdef F_DUPFD 145 result = fcntl (fd, F_DUPFD, desired_fd); 146 # if REPLACE_FCHDIR 147 if (0 <= result) 148 result = _gl_register_dup (fd, result); 149 # endif 150 # else 151 result = dupfd (fd, desired_fd); 152 # endif 153 if (result == -1 && (errno == EMFILE || errno == EINVAL)) 154 errno = EBADF; 155 return result; 156 } 157 #endif /* !HAVE_DUP2 */ 158
