this fix was taken from FreeBSD SVN rev 199953 (Jilles Tjoelker)
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r199953 | jilles | 2009-11-30 07:33:59 +0900 (Mon, 30 Nov 2009) | 16 lines
Fix some cases where file descriptors from redirections leak to programs.
- Redirecting fds that were not open before kept two copies of the
redirected file.
sh -c '{ :; } 7>/dev/null; fstat -p $$; true'
(both fd 7 and 10 remained open)
- File descriptors used to restore things after redirection were not
set close-on-exec, instead they were explicitly closed before executing
a program normally and before executing a shell procedure. The latter
must remain but the former is replaced by close-on-exec.
sh -c 'exec 7</; { exec fstat -p $$; } 7>/dev/null; true'
(fd 10 remained open)
The examples above are simpler than the testsuite because I do not want to
use fstat or procstat in the testsuite.
44f7683783