| 1 | /* Duplicate an open file descriptor to a specified file descriptor. |
| 2 | |
| 3 | Copyright (C) 1999, 2004-2007, 2009-2020 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 <https://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 __CYGWIN__ |
| 33 | |
| 34 | /* Get declarations of the native Windows API functions. */ |
| 35 | # define WIN32_LEAN_AND_MEAN |
| 36 | # include <windows.h> |
| 37 | |
| 38 | # if HAVE_MSVC_INVALID_PARAMETER_HANDLER |
| 39 | # include "msvc-inval.h" |
| 40 | # endif |
| 41 | |
| 42 | /* Get _get_osfhandle. */ |
| 43 | # if GNULIB_MSVC_NOTHROW |
| 44 | # include "msvc-nothrow.h" |
| 45 | # else |
| 46 | # include <io.h> |
| 47 | # endif |
| 48 | |
| 49 | # if HAVE_MSVC_INVALID_PARAMETER_HANDLER |
| 50 | static int |
| 51 | dup2_nothrow (int fd, int desired_fd) |
| 52 | { |
| 53 | int result; |
| 54 | |
| 55 | TRY_MSVC_INVAL |
| 56 | { |
| 57 | result = dup2 (fd, desired_fd); |
| 58 | } |
| 59 | CATCH_MSVC_INVAL |
| 60 | { |
| 61 | errno = EBADF; |
| 62 | result = -1; |
| 63 | } |
| 64 | DONE_MSVC_INVAL; |
| 65 | |
| 66 | return result; |
| 67 | } |
| 68 | # else |
| 69 | # define dup2_nothrow dup2 |
| 70 | # endif |
| 71 | |
| 72 | static int |
| 73 | ms_windows_dup2 (int fd, int desired_fd) |
| 74 | { |
| 75 | int result; |
| 76 | |
| 77 | /* If fd is closed, mingw hangs on dup2 (fd, fd). If fd is open, |
| 78 | dup2 (fd, fd) returns 0, but all further attempts to use fd in |
| 79 | future dup2 calls will hang. */ |
| 80 | if (fd == desired_fd) |
| 81 | { |
| 82 | if ((HANDLE) _get_osfhandle (fd) == INVALID_HANDLE_VALUE) |
| 83 | { |
| 84 | errno = EBADF; |
| 85 | return -1; |
| 86 | } |
| 87 | return fd; |
| 88 | } |
| 89 | |
| 90 | /* Wine 1.0.1 return 0 when desired_fd is negative but not -1: |
| 91 | https://bugs.winehq.org/show_bug.cgi?id=21289 */ |
| 92 | if (desired_fd < 0) |
| 93 | { |
| 94 | errno = EBADF; |
| 95 | return -1; |
| 96 | } |
| 97 | |
| 98 | result = dup2_nothrow (fd, desired_fd); |
| 99 | |
| 100 | if (result == 0) |
| 101 | result = desired_fd; |
| 102 | |
| 103 | return result; |
| 104 | } |
| 105 | |
| 106 | # define dup2 ms_windows_dup2 |
| 107 | |
| 108 | # elif defined __KLIBC__ |
| 109 | |
| 110 | # include <InnoTekLIBC/backend.h> |
| 111 | |
| 112 | static int |
| 113 | klibc_dup2dirfd (int fd, int desired_fd) |
| 114 | { |
| 115 | int tempfd; |
| 116 | int dupfd; |
| 117 | |
| 118 | tempfd = open ("NUL", O_RDONLY); |
| 119 | if (tempfd == -1) |
| 120 | return -1; |
| 121 | |
| 122 | if (tempfd == desired_fd) |
| 123 | { |
| 124 | close (tempfd); |
| 125 | |
| 126 | char path[_MAX_PATH]; |
| 127 | if (__libc_Back_ioFHToPath (fd, path, sizeof (path))) |
| 128 | return -1; |
| 129 | |
| 130 | return open(path, O_RDONLY); |
| 131 | } |
| 132 | |
| 133 | dupfd = klibc_dup2dirfd (fd, desired_fd); |
| 134 | |
| 135 | close (tempfd); |
| 136 | |
| 137 | return dupfd; |
| 138 | } |
| 139 | |
| 140 | static int |
| 141 | klibc_dup2 (int fd, int desired_fd) |
| 142 | { |
| 143 | int dupfd; |
| 144 | struct stat sbuf; |
| 145 | |
| 146 | dupfd = dup2 (fd, desired_fd); |
| 147 | if (dupfd == -1 && errno == ENOTSUP \ |
| 148 | && !fstat (fd, &sbuf) && S_ISDIR (sbuf.st_mode)) |
| 149 | { |
| 150 | close (desired_fd); |
| 151 | |
| 152 | return klibc_dup2dirfd (fd, desired_fd); |
| 153 | } |
| 154 | |
| 155 | return dupfd; |
| 156 | } |
| 157 | |
| 158 | # define dup2 klibc_dup2 |
| 159 | # endif |
| 160 | |
| 161 | int |
| 162 | rpl_dup2 (int fd, int desired_fd) |
| 163 | { |
| 164 | int result; |
| 165 | |
| 166 | # ifdef F_GETFL |
| 167 | /* On Linux kernels 2.6.26-2.6.29, dup2 (fd, fd) returns -EBADF. |
| 168 | On Cygwin 1.5.x, dup2 (1, 1) returns 0. |
| 169 | On Cygwin 1.7.17, dup2 (1, -1) dumps core. |
| 170 | On Cygwin 1.7.25, dup2 (1, 256) can dump core. |
| 171 | On Haiku, dup2 (fd, fd) mistakenly clears FD_CLOEXEC. */ |
| 172 | # if HAVE_SETDTABLESIZE |
| 173 | setdtablesize (desired_fd + 1); |
| 174 | # endif |
| 175 | if (desired_fd < 0) |
| 176 | fd = desired_fd; |
| 177 | if (fd == desired_fd) |
| 178 | return fcntl (fd, F_GETFL) == -1 ? -1 : fd; |
| 179 | # endif |
| 180 | |
| 181 | result = dup2 (fd, desired_fd); |
| 182 | |
| 183 | /* Correct an errno value on FreeBSD 6.1 and Cygwin 1.5.x. */ |
| 184 | if (result == -1 && errno == EMFILE) |
| 185 | errno = EBADF; |
| 186 | # if REPLACE_FCHDIR |
| 187 | if (fd != desired_fd && result != -1) |
| 188 | result = _gl_register_dup (fd, result); |
| 189 | # endif |
| 190 | return result; |
| 191 | } |
| 192 | |
| 193 | #else /* !HAVE_DUP2 */ |
| 194 | |
| 195 | /* On older platforms, dup2 did not exist. */ |
| 196 | |
| 197 | # ifndef F_DUPFD |
| 198 | static int |
| 199 | dupfd (int fd, int desired_fd) |
| 200 | { |
| 201 | int duplicated_fd = dup (fd); |
| 202 | if (duplicated_fd < 0 || duplicated_fd == desired_fd) |
| 203 | return duplicated_fd; |
| 204 | else |
| 205 | { |
| 206 | int r = dupfd (fd, desired_fd); |
| 207 | int e = errno; |
| 208 | close (duplicated_fd); |
| 209 | errno = e; |
| 210 | return r; |
| 211 | } |
| 212 | } |
| 213 | # endif |
| 214 | |
| 215 | int |
| 216 | dup2 (int fd, int desired_fd) |
| 217 | { |
| 218 | int result = fcntl (fd, F_GETFL) < 0 ? -1 : fd; |
| 219 | if (result == -1 || fd == desired_fd) |
| 220 | return result; |
| 221 | close (desired_fd); |
| 222 | # ifdef F_DUPFD |
| 223 | result = fcntl (fd, F_DUPFD, desired_fd); |
| 224 | # if REPLACE_FCHDIR |
| 225 | if (0 <= result) |
| 226 | result = _gl_register_dup (fd, result); |
| 227 | # endif |
| 228 | # else |
| 229 | result = dupfd (fd, desired_fd); |
| 230 | # endif |
| 231 | if (result == -1 && (errno == EMFILE || errno == EINVAL)) |
| 232 | errno = EBADF; |
| 233 | return result; |
| 234 | } |
| 235 | #endif /* !HAVE_DUP2 */ |