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Diffstat (limited to '')
-rw-r--r-- | grub-core/lib/gnulib/cloexec.c | 83 |
1 files changed, 83 insertions, 0 deletions
diff --git a/grub-core/lib/gnulib/cloexec.c b/grub-core/lib/gnulib/cloexec.c new file mode 100644 index 0000000..db42576 --- /dev/null +++ b/grub-core/lib/gnulib/cloexec.c @@ -0,0 +1,83 @@ +/* cloexec.c - set or clear the close-on-exec descriptor flag + + Copyright (C) 1991, 2004-2006, 2009-2019 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/>. + + The code is taken from glibc/manual/llio.texi */ + +#include <config.h> + +#include "cloexec.h" + +#include <errno.h> +#include <fcntl.h> +#include <unistd.h> + +/* Set the 'FD_CLOEXEC' flag of DESC if VALUE is true, + or clear the flag if VALUE is false. + Return 0 on success, or -1 on error with 'errno' set. + + Note that on MingW, this function does NOT protect DESC from being + inherited into spawned children. Instead, either use dup_cloexec + followed by closing the original DESC, or use interfaces such as + open or pipe2 that accept flags like O_CLOEXEC to create DESC + non-inheritable in the first place. */ + +int +set_cloexec_flag (int desc, bool value) +{ +#ifdef F_SETFD + + int flags = fcntl (desc, F_GETFD, 0); + + if (0 <= flags) + { + int newflags = (value ? flags | FD_CLOEXEC : flags & ~FD_CLOEXEC); + + if (flags == newflags + || fcntl (desc, F_SETFD, newflags) != -1) + return 0; + } + + return -1; + +#else /* !F_SETFD */ + + /* Use dup2 to reject invalid file descriptors; the cloexec flag + will be unaffected. */ + if (desc < 0) + { + errno = EBADF; + return -1; + } + if (dup2 (desc, desc) < 0) + /* errno is EBADF here. */ + return -1; + + /* There is nothing we can do on this kind of platform. Punt. */ + return 0; +#endif /* !F_SETFD */ +} + + +/* Duplicates a file handle FD, while marking the copy to be closed + prior to exec or spawn. Returns -1 and sets errno if FD could not + be duplicated. */ + +int +dup_cloexec (int fd) +{ + return fcntl (fd, F_DUPFD_CLOEXEC, 0); +} |