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@redhat.com> --- 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@redhat.com +1-801-349-2682 Libvirt virtualization library http://libvirt.org