50 lines
2.0 KiB
Diff
50 lines
2.0 KiB
Diff
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Subject: tools/console: xenconsole tolerate tty errors
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From: Ian Jackson ian.jackson@eu.citrix.com Thu Feb 27 17:46:49 2014 +0000
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Date: Wed Mar 19 13:37:19 2014 +0000:
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Git: 39ba2989b10b6a1852e253b204eb010f8e7026f1
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Since 28d386fc4341 (XSA-57), libxl writes an empty value for the
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console tty node, with read-only permission for the guest, when
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setting up pv console "frontends". (The actual tty value is later set
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by xenconsoled.) Writing an empty node is not strictly necessary to
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stop the frontend from writing dangerous values here, but it is a good
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belt-and-braces approach.
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Unfortunately this confuses xenconsole. It reads the empty value, and
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tries to open it as the tty. xenconsole then exits.
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Fix this by having xenconsole treat an empty value the same way as no
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value at all.
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Also, make the error opening the tty be nonfatal: we just print a
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warning, but do not exit. I think this is helpful in theoretical
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situations where xenconsole is racing with libxl and/or xenconsoled.
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Signed-off-by: Ian Jackson <Ian.Jackson@eu.citrix.com>
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Acked-by: Ian Campbell <Ian.Campbell@citrix.com>
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CC: George Dunlap <george.dunlap@eu.citrix.com>
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---
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v2: Combine two conditions and move the free
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Index: xen-4.4.0-testing/tools/console/client/main.c
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===================================================================
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--- xen-4.4.0-testing.orig/tools/console/client/main.c
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+++ xen-4.4.0-testing/tools/console/client/main.c
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@@ -115,12 +115,12 @@ static int get_pty_fd(struct xs_handle *
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/* We only watch for one thing, so no need to
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* disambiguate: just read the pty path */
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pty_path = xs_read(xs, XBT_NULL, path, &len);
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- if (pty_path != NULL) {
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+ if (pty_path != NULL && pty_path[0] != '\0') {
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pty_fd = open(pty_path, O_RDWR | O_NOCTTY);
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if (pty_fd == -1)
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- err(errno, "Could not open tty `%s'", pty_path);
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- free(pty_path);
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+ warn("Could not open tty `%s'", pty_path);
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}
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+ free(pty_path);
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}
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} while (pty_fd == -1 && (now = time(NULL)) < start + seconds);
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