diff options
Diffstat (limited to 'lib/dup2.c')
| -rw-r--r-- | lib/dup2.c | 235 |
1 files changed, 235 insertions, 0 deletions
diff --git a/lib/dup2.c b/lib/dup2.c new file mode 100644 index 0000000..88ef259 --- /dev/null +++ b/lib/dup2.c @@ -0,0 +1,235 @@ +/* Duplicate an open file descriptor to a specified file descriptor. + + Copyright (C) 1999, 2004-2007, 2009-2020 Free Software Foundation, Inc. + + This program is free software: you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation; either version 3 of the License, or + (at your option) any later version. + + This program is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU General Public License for more details. + + You should have received a copy of the GNU General Public License + along with this program. If not, see <https://www.gnu.org/licenses/>. */ + +/* written by Paul Eggert */ + +#include <config.h> + +/* Specification. */ +#include <unistd.h> + +#include <errno.h> +#include <fcntl.h> + +#if HAVE_DUP2 + +# undef dup2 + +# if defined _WIN32 && ! defined __CYGWIN__ + +/* Get declarations of the native Windows API functions. */ +# define WIN32_LEAN_AND_MEAN +# include <windows.h> + +# if HAVE_MSVC_INVALID_PARAMETER_HANDLER +# include "msvc-inval.h" +# endif + +/* Get _get_osfhandle. */ +# if GNULIB_MSVC_NOTHROW +# include "msvc-nothrow.h" +# else +# include <io.h> +# endif + +# if HAVE_MSVC_INVALID_PARAMETER_HANDLER +static int +dup2_nothrow (int fd, int desired_fd) +{ + int result; + + TRY_MSVC_INVAL + { + result = dup2 (fd, desired_fd); + } + CATCH_MSVC_INVAL + { + errno = EBADF; + result = -1; + } + DONE_MSVC_INVAL; + + return result; +} +# else +# define dup2_nothrow dup2 +# endif + +static int +ms_windows_dup2 (int fd, int desired_fd) +{ + int result; + + /* If fd is closed, mingw hangs on dup2 (fd, fd). If fd is open, + dup2 (fd, fd) returns 0, but all further attempts to use fd in + future dup2 calls will hang. */ + if (fd == desired_fd) + { + if ((HANDLE) _get_osfhandle (fd) == INVALID_HANDLE_VALUE) + { + errno = EBADF; + return -1; + } + return fd; + } + + /* Wine 1.0.1 return 0 when desired_fd is negative but not -1: + https://bugs.winehq.org/show_bug.cgi?id=21289 */ + if (desired_fd < 0) + { + errno = EBADF; + return -1; + } + + result = dup2_nothrow (fd, desired_fd); + + if (result == 0) + result = desired_fd; + + return result; +} + +# define dup2 ms_windows_dup2 + +# elif defined __KLIBC__ + +# include <InnoTekLIBC/backend.h> + +static int +klibc_dup2dirfd (int fd, int desired_fd) +{ + int tempfd; + int dupfd; + + tempfd = open ("NUL", O_RDONLY); + if (tempfd == -1) + return -1; + + if (tempfd == desired_fd) + { + close (tempfd); + + char path[_MAX_PATH]; + if (__libc_Back_ioFHToPath (fd, path, sizeof (path))) + return -1; + + return open(path, O_RDONLY); + } + + dupfd = klibc_dup2dirfd (fd, desired_fd); + + close (tempfd); + + return dupfd; +} + +static int +klibc_dup2 (int fd, int desired_fd) +{ + int dupfd; + struct stat sbuf; + + dupfd = dup2 (fd, desired_fd); + if (dupfd == -1 && errno == ENOTSUP \ + && !fstat (fd, &sbuf) && S_ISDIR (sbuf.st_mode)) + { + close (desired_fd); + + return klibc_dup2dirfd (fd, desired_fd); + } + + return dupfd; +} + +# define dup2 klibc_dup2 +# endif + +int +rpl_dup2 (int fd, int desired_fd) +{ + int result; + +# ifdef F_GETFL + /* On Linux kernels 2.6.26-2.6.29, dup2 (fd, fd) returns -EBADF. + On Cygwin 1.5.x, dup2 (1, 1) returns 0. + On Cygwin 1.7.17, dup2 (1, -1) dumps core. + On Cygwin 1.7.25, dup2 (1, 256) can dump core. + On Haiku, dup2 (fd, fd) mistakenly clears FD_CLOEXEC. */ +# if HAVE_SETDTABLESIZE + setdtablesize (desired_fd + 1); +# endif + if (desired_fd < 0) + fd = desired_fd; + if (fd == desired_fd) + return fcntl (fd, F_GETFL) == -1 ? -1 : fd; +# endif + + result = dup2 (fd, desired_fd); + + /* Correct an errno value on FreeBSD 6.1 and Cygwin 1.5.x. */ + if (result == -1 && errno == EMFILE) + errno = EBADF; +# if REPLACE_FCHDIR + if (fd != desired_fd && result != -1) + result = _gl_register_dup (fd, result); +# endif + return result; +} + +#else /* !HAVE_DUP2 */ + +/* On older platforms, dup2 did not exist. */ + +# ifndef F_DUPFD +static int +dupfd (int fd, int desired_fd) +{ + int duplicated_fd = dup (fd); + if (duplicated_fd < 0 || duplicated_fd == desired_fd) + return duplicated_fd; + else + { + int r = dupfd (fd, desired_fd); + int e = errno; + close (duplicated_fd); + errno = e; + return r; + } +} +# endif + +int +dup2 (int fd, int desired_fd) +{ + int result = fcntl (fd, F_GETFL) < 0 ? -1 : fd; + if (result == -1 || fd == desired_fd) + return result; + close (desired_fd); +# ifdef F_DUPFD + result = fcntl (fd, F_DUPFD, desired_fd); +# if REPLACE_FCHDIR + if (0 <= result) + result = _gl_register_dup (fd, result); +# endif +# else + result = dupfd (fd, desired_fd); +# endif + if (result == -1 && (errno == EMFILE || errno == EINVAL)) + errno = EBADF; + return result; +} +#endif /* !HAVE_DUP2 */ |