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51 lines
1.4 KiB
C
51 lines
1.4 KiB
C
///////////////////////////////////////////////////////////////////////////////
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//
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/// \file open_stdxxx.h
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/// \brief Make sure that file descriptors 0, 1, and 2 are open
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//
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// This code has been put into the public domain.
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//
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// This library is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
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//
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///////////////////////////////////////////////////////////////////////////////
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#ifndef OPEN_STDXXX_H
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#define OPEN_STDXXX_H
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#include <stdlib.h>
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#include <fcntl.h>
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#include <unistd.h>
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static void
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open_stdxxx(int status)
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{
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for (int i = 0; i <= 2; ++i) {
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// We use fcntl() to check if the file descriptor is open.
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if (fcntl(i, F_GETFD) == -1 && errno == EBADF) {
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// With stdin, we could use /dev/full so that
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// writing to stdin would fail. However, /dev/full
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// is Linux specific, and if the program tries to
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// write to stdin, there's already a problem anyway.
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const int fd = open("/dev/null", O_NOCTTY
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| (i == 0 ? O_WRONLY : O_RDONLY));
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if (fd != i) {
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// Something went wrong. Exit with the
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// exit status we were given. Don't try
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// to print an error message, since stderr
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// may very well be non-existent. This
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// error should be extremely rare.
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(void)close(fd);
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exit(status);
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}
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}
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}
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return;
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}
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#endif
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