On Sat, Sep 08, 2018 at 08:47:28PM +0800, Nan Xiao wrote:
> I don't think need "if (fd > STDERR_FILENO)" cause the fd is a new
> opened file descriptor. If its value is less or equal than
> `STDERR_FILENO', it means the stdin or stderr is already closed
> intentionally. So it should be OK close fd again.
In general it is a bad idea to start programs without opened 0 1 2
file descriptors. Then the next open will fill the gap and a
printf() or err() may write to random files.
Some paranoid daemons like syslogd(8) dup2 /dev/null to them. And
there is this check:
if (nullfd > 2)
close(nullfd);
If course nohup(1) is not that paranoid. And the isatty() checks
prevent that the stdio file decriptor gaps get filled. But before
you plugged the fd leak, "nohup true 2>&-" would write to nohup.out.
Perhaps we could make nohup(1) a bit more sane by checks like this.
errno = 0;
if (isatty(STDOUT_FILENO) || errno == EBADF)
bluhm
