On 11/19/2010 09:15 AM, Cole Robinson wrote:
> If we don't escape ' or \ xend can't parse the generated sexpr. This
> might over apply the EscapeSexpr routine, but it shouldn't hurt.
>
> Signed-off-by: Cole Robinson <crobinso@xxxxxxxxxx>
> ---
> src/util/buf.c | 79 +++++++++++++++++++
> src/util/buf.h | 1 +
> src/xen/xend_internal.c | 115 +++++++++++++++-------------
> tests/xml2sexprdata/xml2sexpr-escape.sexpr | 1 +
> tests/xml2sexprdata/xml2sexpr-escape.xml | 24 ++++++
> tests/xml2sexprtest.c | 1 +
> 6 files changed, 169 insertions(+), 52 deletions(-)
> create mode 100644 tests/xml2sexprdata/xml2sexpr-escape.sexpr
> create mode 100644 tests/xml2sexprdata/xml2sexpr-escape.xml
>
> diff --git a/src/util/buf.c b/src/util/buf.c
> index 553e2a0..90034ad 100644
> --- a/src/util/buf.c
> +++ b/src/util/buf.c
> @@ -379,6 +379,85 @@ err:
> }
>
> /**
> + * virBufferEscapeSexpr:
> + * @buf: the buffer to dump
> + * @format: a printf like format string but with only one %s parameter
> + * @str: the string argument which need to be escaped
> + *
> + * Do a formatted print with a single string to an sexpr buffer. The string
> + * is escaped to avoid generating a sexpr that xen will choke on. This
> + * doesn't fully escape the sexpr, just enough for our code to work.
> + */
> +void
> +virBufferEscapeSexpr(const virBufferPtr buf,
> + const char *format,
> + const char *str)
> +{
> + int size, count, len, grow_size;
> + char *escaped, *out;
> + const char *cur;
> +
> + if ((format == NULL) || (buf == NULL) || (str == NULL))
> + return;
> +
> + if (buf->error)
> + return;
> +
> + len = strlen(str);
Right here, is it worth adding:
if (strcspn(str, "\\'") == len) {
virBufferVSprintf(buf, format, str);
return;
}
> + if (VIR_ALLOC_N(escaped, 2 * len + 1) < 0) {
> + virBufferNoMemory(buf);
> + return;
> + }
so as to avoid the alloc in the common case of nothing to escape?
> + *out = 0;
> +
> + if ((buf->use >= buf->size) &&
> + virBufferGrow(buf, 100) < 0) {
> + goto err;
> + }
That 100 looks wrong; shouldn't it instead be max(100,out-escaped)? For
that matter, why do all this low level stuff; wouldn't it be easier
after *out = 0 to just do:
virBufferVSpring(buf, format, escaped);
VIR_FREE(escaped);
return;
and leave all the resizing and snprintf stuff to the already written
function?
> diff --git a/src/util/buf.h b/src/util/buf.h
> index 6616898..54f4de5 100644
> --- a/src/util/buf.h
> @@ -5400,39 +5401,42 @@ xenDaemonFormatSxprDisk(virConnectPtr conn ATTRIBUTE_UNUSED,
>
> if (hvm) {
> /* Xend <= 3.0.2 wants a ioemu: prefix on devices for HVM */
> - if (xendConfigVersion == 1)
> - virBufferVSprintf(buf, "(dev 'ioemu:%s')", def->dst);
> - else /* But newer does not */
> - virBufferVSprintf(buf, "(dev '%s:%s')", def->dst,
> - def->device == VIR_DOMAIN_DISK_DEVICE_CDROM ?
> - "cdrom" : "disk");
> + if (xendConfigVersion == 1) {
> + virBufferEscapeSexpr(buf, "(dev 'ioemu:%s')", def->dst);
> + } else {
> + /* But newer does not */
> + virBufferEscapeSexpr(buf, "(dev '%s:", def->dst);
> + virBufferEscapeSexpr(buf, "%s')",
> + def->device == VIR_DOMAIN_DISK_DEVICE_CDROM ?
> + "cdrom" : "disk");
This can be virBufferVSprintf(buf, "%s')",...), given that the only two
possible strings for %s don't need escaping.
> @@ -5680,7 +5685,8 @@ xenDaemonFormatSxprSound(virDomainDefPtr def,
> def->sounds[i]->model);
> return -1;
> }
> - virBufferVSprintf(buf, "%s%s", i ? "," : "", str);
> + virBufferVSprintf(buf, "%s", i ? "," : "");
I'd write this as 'if (i) virBufferAddChar(buf, ',')' rather than a
complicated VSprintf.
> diff --git a/tests/xml2sexprdata/xml2sexpr-escape.xml b/tests/xml2sexprdata/xml2sexpr-escape.xml
> new file mode 100644
> index 0000000..73beb6b
> --- /dev/null
> +++ b/tests/xml2sexprdata/xml2sexpr-escape.xml
> @@ -0,0 +1,24 @@
> +<domain type='xen' id='15'>
> + <name>fvtest</name>
> + <uuid>596a5d2171f48fb2e068e2386a5c413e</uuid>
> + <os>
> + <type>hvm</type>
> + <kernel>/var/lib/xen/vmlinuz.2Dn2YT</kernel>
> + <initrd>/var/lib/xen/initrd.img.0u-Vhq</initrd>
> + <cmdline> method=http://&""download.fedora.devel.redhat.com/pub/fedora/linux/core/test/5.91/x86_64/os </cmdline>
Seems unusual to have & and " in a URL; but the point of this test was
not so much a real configuration as a way to expose the sexpr escaping
code path. Is there any better place to stick this where it won't be
quite so confusing?
--
Eric Blake eblake@xxxxxxxxxx +1-801-349-2682
Libvirt virtualization library http://libvirt.org
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