Messages in this thread | | | From | Zefram <> | Subject | Opening half a pseudo tty | Date | Fri, 12 Apr 1996 22:12:42 +0100 (BST) |
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In Linux 1.3.80, I tried opening /dev/tty5, when /dev/pty5 had not been opened at all. The process busy-waited in kernel space, in the open syscall, until either interrupted (by, for example, SIGINT), or another process opened /dev/pty5, at which point the open succeeded and returned normally. The mode in which the two ends of the pty are opened makes no difference. If the pty end is opened first, the tty open succeeds and returns quickly.
Using the Alt-ScrollLock thing, I got a list of EIPs in functions such as n_tty_open(), pty_open() and related functions. pty_open() is evidently being called arbitrarily many times. At a rough guess, the ERESTARTSYS in pty_open() is the culprit. I'm not certain of that though. Could someone explain just what ERESTARTSYS does?
-zefram
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