54 lines
1.7 KiB
Awk
54 lines
1.7 KiB
Awk
# From arnold@f7.net Fri Nov 26 11:53:12 2004
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# X-Envelope-From: james@nocrew.org
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# X-Envelope-To: <arnold@skeeve.com>
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# To: bug-gawk@gnu.org
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# Subject: gawk 3.1.4: reproducible hang, regression from 3.1.3
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# From: James Troup <james@nocrew.org>
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# Date: Fri, 26 Nov 2004 03:14:05 +0000
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# Message-ID: <877jo9qp36.fsf@shiri.gloaming.local>
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# User-Agent: Gnus/5.1006 (Gnus v5.10.6) Emacs/21.3 (gnu/linux)
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# MIME-Version: 1.0
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# Content-Type: text/plain; charset=us-ascii
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#
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#
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# Hi,
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#
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# A Debian user reported[0] gawk 3.1.4 broke a (relatively) complex
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# program that makes extensive use of awk, called 'apt-move'. I finally
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# managed to reduced the problem down to a 3 line test case, enclosed
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# below[1].
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#
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# I believe the problem comes from the following code, introduced in
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# 3.1.4:
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#
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# [io.c, line 560]
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# | for (rp = red_head; rp != NULL; rp = rp->next) {
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# | if ((rp->flag & RED_EOF) && tree->type == Node_redirect_pipein) {
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# | if (rp->pid != -1)
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# | wait_any(0);
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# | }
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#
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# The problem is that, if we have an existing redirect which is a simple
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# file redirect[b] and it's hit EOF and we try to create a new '|'
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# redirect[c], this new code will try to wait(2) and if there are any
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# other redirects which _did_ spawn a child (like [a]) the wait() will
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# hang indefinitely waiting for it to exit.
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#
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# Hope that makes sense :)
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#
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# --
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# James
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#
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# [0] http://bugs.debian.org/263964
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#
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# [1]
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# ================================================================================
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#!/usr/bin/gawk -f
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BEGIN {
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printf "" | "cat" # [a]
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getline line < "/dev/null" # [b]
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"true" | getline line # [c]
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}
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# ================================================================================
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