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Diffstat (limited to '')
-rw-r--r-- | src/common/open_stdxxx.h | 50 |
1 files changed, 50 insertions, 0 deletions
diff --git a/src/common/open_stdxxx.h b/src/common/open_stdxxx.h new file mode 100644 index 00000000..d0ac15af --- /dev/null +++ b/src/common/open_stdxxx.h @@ -0,0 +1,50 @@ +/////////////////////////////////////////////////////////////////////////////// +// +/// \file open_stdxxx.h +/// \brief Make sure that file descriptors 0, 1, and 2 are open +// +// This code has been put into the public domain. +// +// This library 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. +// +/////////////////////////////////////////////////////////////////////////////// + +#ifndef OPEN_STDXXX_H +#define OPEN_STDXXX_H + +#include <stdlib.h> +#include <fcntl.h> +#include <unistd.h> + + +static void +open_stdxxx(int status) +{ + for (int i = 0; i <= 2; ++i) { + // We use fcntl() to check if the file descriptor is open. + if (fcntl(i, F_GETFD) == -1 && errno == EBADF) { + // With stdin, we could use /dev/full so that + // writing to stdin would fail. However, /dev/full + // is Linux specific, and if the program tries to + // write to stdin, there's already a problem anyway. + const int fd = open("/dev/null", O_NOCTTY + | (i == 0 ? O_WRONLY : O_RDONLY)); + + if (fd != i) { + // Something went wrong. Exit with the + // exit status we were given. Don't try + // to print an error message, since stderr + // may very well be non-existent. This + // error should be extremely rare. + (void)close(fd); + exit(status); + } + } + } + + return; +} + +#endif |