[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 <hahn(a)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