[libvirt] [PATCH] XML: Escape double-hyphens in XML comment
To quote http://www.w3.org/TR/REC-xml/#sec-comments:
For compatibility, the string -- (double-hyphen) must not occur within
comments.
For example this breaks creating snapshots:
$ virsh snapshot-create-as $VM comment--bug
$ xmllint --noout /var/lib/libvirt/qemu/snapshot/$VM/comment--bug.xml
/var/lib/libvirt/qemu/snapshot/$VM/comment--bug.xml:4: parser error : Comment
not terminated
!--
WARNING: THIS IS AN AUTO-GENERATED FILE. CHANGES
virsh snapshot-edit $VM comment--bug
$ /etc/init.d/libvirt-bin restart
error : qemuDomainSnapshotLoad:367 : Failed to parse snapshot XML from file
'/var/lib/libvirt/qemu/snapshot/$VM/comment--bug.xml'
$ virsh snapshot-list ucs32-33787-performance
Name Creation Time State
Also applies to QEMU domains, where the name contains double-hyphens.
As a work-around break any sequence of consecutive hyphens by inserting
(arbitrarily chosen) backslashes, as there is no escaping rule defined
as far as I know.
I've not yet checked, how libvirt/libxml handles a document with
multiple root nodes, as this would create interesting possibilities if I
can name my domain
--domain...devices...disk...source dev=/dev/sda/...
It might break on the / as this is the only prohibited character for
QEMU domains, as the name is directly used as a file name.
To fix such broken files (by hand), remove the broken comment by doing
something like this after making sure libvirtd is stopped:
sed -i -ne '/^domainsnapshot$/,$p' /var/lib/libvirt/qemu/snapshot/*/*.xml
sed -i -ne '/^domain /,$p' /etc/libvirt/qemu/*.xml
sed -i -ne '/^pool /,$p' /etc/libvirt/storage/*.xml
@Debian: The bug is also in libvirt-0.9.12.
Signed-off-by: Philipp Hahn h...@univention.de
---
src/util/virxml.c | 34 ++
1 file changed, 30 insertions(+), 4 deletions(-)
diff --git a/src/util/virxml.c b/src/util/virxml.c
index dd530a6..ad45e68 100644
--- a/src/util/virxml.c
+++ b/src/util/virxml.c
@@ -798,6 +798,34 @@ const char *virXMLPickShellSafeComment(const char *str1,
const char *str2)
return NULL;
}
+/*
+ * Break sequence of hyphens by inserting (arbitrarily chosen) backslashes.
+ * http://www.w3.org/TR/REC-xml/#sec-comments:
+ * For compatibility, the string -- (double-hyphen) must not occur within
+ * comments.
+ */
+static int virXMLEmitEscapedComment(int fd,
+const char *str)
+{
+size_t len;
+
+if (!strstr(str, --)) {
+len = strlen(str);
+if (safewrite(fd, str, len) != len)
+return -1;
+return 0;
+}
+
+for (;*str;str++) {
+if (safewrite(fd, str, 1) != 1)
+return -1;
+if (str[0] == '-' str[1] == '-')
+if (safewrite(fd, \\, 1) != 1)
+return -1;
+}
+return 0;
+}
+
static int virXMLEmitWarning(int fd,
const char *name,
const char *cmd)
@@ -822,16 +850,14 @@ static int virXMLEmitWarning(int fd,
if (safewrite(fd, prologue, len) != len)
return -1;
-len = strlen(cmd);
-if (safewrite(fd, cmd, len) != len)
+if (virXMLEmitEscapedComment(fd, cmd) 0)
return -1;
if (name) {
if (safewrite(fd, , 1) != 1)
return -1;
-len = strlen(name);
-if (safewrite(fd, name, len) != len)
+if (virXMLEmitEscapedComment(fd, name) 0)
return -1;
}
--
1.8.5.3
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Re: [libvirt] [PATCH] XML: Escape double-hyphens in XML comment
On 02/21/2014 10:01 AM, Philipp Hahn wrote: To quote http://www.w3.org/TR/REC-xml/#sec-comments: For compatibility, the string -- (double-hyphen) must not occur within comments. For example this breaks creating snapshots: $ virsh snapshot-create-as $VM comment--bug $ xmllint --noout /var/lib/libvirt/qemu/snapshot/$VM/comment--bug.xml /var/lib/libvirt/qemu/snapshot/$VM/comment--bug.xml:4: parser error : Comment not terminated !-- WARNING: THIS IS AN AUTO-GENERATED FILE. CHANGES virsh snapshot-edit $VM comment--bug $ /etc/init.d/libvirt-bin restart error : qemuDomainSnapshotLoad:367 : Failed to parse snapshot XML from file '/var/lib/libvirt/qemu/snapshot/$VM/comment--bug.xml' $ virsh snapshot-list ucs32-33787-performance Name Creation Time State Also applies to QEMU domains, where the name contains double-hyphens. This no longer reproduces with current master, it has been fixed by either of: commit 0b121614a2086a8e66ae1f004fe912ba7c1d8a75 Author: Ján Tomko jto...@redhat.com CommitDate: 2012-10-29 14:38:43 +0100 xml: print uuids in the warning commit 9b704ab8235af010b1fda4886201aab02098b969 Author: Ján Tomko jto...@redhat.com CommitDate: 2012-10-23 14:24:31 +0200 xml: omit domain name from comment if it contains double hyphen Jan signature.asc Description: OpenPGP digital signature -- libvir-list mailing list libvir-list@redhat.com https://www.redhat.com/mailman/listinfo/libvir-list
Re: [libvirt] [PATCH] XML: Escape double-hyphens in XML comment
On 21.02.2014 12:18, Ján Tomko wrote: This no longer reproduces with current master, it has been fixed by either of: commit 0b121614a2086a8e66ae1f004fe912ba7c1d8a75 Author: Ján Tomko jto...@redhat.com CommitDate: 2012-10-29 14:38:43 +0100 xml: print uuids in the warning commit 9b704ab8235af010b1fda4886201aab02098b969 Author: Ján Tomko jto...@redhat.com CommitDate: 2012-10-23 14:24:31 +0200 xml: omit domain name from comment if it contains double hyphen Thanks and sorry for the noise - your solution looks much better :-) Philipp signature.asc Description: OpenPGP digital signature -- libvir-list mailing list libvir-list@redhat.com https://www.redhat.com/mailman/listinfo/libvir-list
Re: [libvirt] [PATCH] XML: Escape double-hyphens in XML comment
On 02/21/2014 02:01 AM, Philipp Hahn wrote:
To quote http://www.w3.org/TR/REC-xml/#sec-comments:
For compatibility, the string -- (double-hyphen) must not occur within
comments.
+/*
+ * Break sequence of hyphens by inserting (arbitrarily chosen) backslashes.
+ * http://www.w3.org/TR/REC-xml/#sec-comments:
+ * For compatibility, the string -- (double-hyphen) must not occur within
+ * comments.
+ */
+static int virXMLEmitEscapedComment(int fd,
+const char *str)
+{
+size_t len;
+
+if (!strstr(str, --)) {
+len = strlen(str);
+if (safewrite(fd, str, len) != len)
+return -1;
+return 0;
+}
+
+for (;*str;str++) {
Style: spaces after ';'.
This would also be a perfect candidate for Dan's virStringReplace patch,
rather than open-coding your own replacement loop.
That, and Jan already pointed out better patches to be backported :)
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Eric Blake eblake redhat com+1-919-301-3266
Libvirt virtualization library http://libvirt.org
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