Almost there...
git-svn-id: svn://chrome-svn/chromeos/trunk@24 06c00378-0e64-4dae-be16-12b19f9950a1
diff --git a/update_check_action.cc b/update_check_action.cc
new file mode 100644
index 0000000..a4942a6
--- /dev/null
+++ b/update_check_action.cc
@@ -0,0 +1,281 @@
+// Copyright (c) 2009 The Chromium OS Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "update_engine/update_check_action.h"
+#include <sstream>
+
+#include <libxml/parser.h>
+#include <libxml/xpath.h>
+#include <libxml/xpathInternals.h>
+
+#include "update_engine/action_pipe.h"
+
+using std::string;
+
+namespace chromeos_update_engine {
+
+const char* const UpdateCheckParams::kAppId(
+ "87efface-864d-49a5-9bb3-4b050a7c227a");
+const char* const UpdateCheckParams::kOsPlatform("Chrome OS");
+const char* const UpdateCheckParams::kOsVersion("Indy");
+
+namespace {
+
+const string kGupdateVersion("ChromeOSUpdateEngine-0.1.0.0");
+
+// This is handy for passing strings into libxml2
+#define ConstXMLStr(x) (reinterpret_cast<const xmlChar*>(x))
+
+// These are for scoped_ptr_malloc, which is like scoped_ptr, but allows
+// a custom free() function to be specified.
+class ScopedPtrXmlDocFree {
+ public:
+ inline void operator()(void* x) const {
+ xmlFreeDoc(reinterpret_cast<xmlDoc*>(x));
+ }
+};
+class ScopedPtrXmlFree {
+ public:
+ inline void operator()(void* x) const {
+ xmlFree(x);
+ }
+};
+class ScopedPtrXmlXPathObjectFree {
+ public:
+ inline void operator()(void* x) const {
+ xmlXPathFreeObject(reinterpret_cast<xmlXPathObject*>(x));
+ }
+};
+class ScopedPtrXmlXPathContextFree {
+ public:
+ inline void operator()(void* x) const {
+ xmlXPathFreeContext(reinterpret_cast<xmlXPathContext*>(x));
+ }
+};
+
+// Returns a properly formatted omaha request for an update check
+string FormatRequest(const UpdateCheckParams& params) {
+ return string("<?xml version=\"1.0\" encoding=\"UTF-8\"?>\n"
+ "<o:gupdate xmlns:o=\"http://www.google.com/update2/request\" "
+ "version=\"" + XmlEncode(kGupdateVersion) + "\" protocol=\"2.0\" "
+ "machineid=\"") + XmlEncode(params.machine_id) + "\" ismachine=\"1\" "
+ "userid=\"" + XmlEncode(params.user_id) + "\">\n"
+ " <o:os version=\"" + XmlEncode(params.os_version) + "\" platform=\"" +
+ XmlEncode(params.os_platform) + "\" sp=\"" +
+ XmlEncode(params.os_sp) + "\"></o:os>\n"
+ " <o:app appid=\"" + XmlEncode(params.app_id) + "\" version=\"" +
+ XmlEncode(params.app_version) + "\" "
+ "lang=\"" + XmlEncode(params.app_lang) + "\" track=\"" +
+ XmlEncode(params.app_track) + "\">\n"
+ " <o:ping active=\"0\"></o:ping>\n"
+ " <o:updatecheck></o:updatecheck>\n"
+ " </o:app>\n"
+ "</o:gupdate>\n";
+}
+} // namespace {}
+
+// Encodes XML entities in a given string with libxml2. input must be
+// UTF-8 formatted. Output will be UTF-8 formatted.
+string XmlEncode(const string& input) {
+// // TODO(adlr): if allocating a new xmlDoc each time is taking up too much
+// // cpu, considering creating one and caching it.
+// scoped_ptr_malloc<xmlDoc, ScopedPtrXmlDocFree> xml_doc(
+// xmlNewDoc(ConstXMLStr("1.0")));
+// if (!xml_doc.get()) {
+// LOG(ERROR) << "Unable to create xmlDoc";
+// return "";
+// }
+ scoped_ptr_malloc<xmlChar, ScopedPtrXmlFree> str(
+ xmlEncodeEntitiesReentrant(NULL, ConstXMLStr(input.c_str())));
+ return string(reinterpret_cast<const char *>(str.get()));
+}
+
+UpdateCheckAction::UpdateCheckAction(const UpdateCheckParams& params,
+ HttpFetcher* http_fetcher)
+ : params_(params), http_fetcher_(http_fetcher) {}
+
+UpdateCheckAction::~UpdateCheckAction() {}
+
+void UpdateCheckAction::PerformAction() {
+ http_fetcher_->set_delegate(this);
+ string request_post(FormatRequest(params_));
+ http_fetcher_->SetPostData(request_post.data(), request_post.size());
+ http_fetcher_->BeginTransfer("https://tools.google.com/service/update2");
+}
+
+void UpdateCheckAction::TerminateProcessing() {
+ http_fetcher_->TerminateTransfer();
+}
+
+// We just store the response in the buffer. Once we've received all bytes,
+// we'll look in the buffer and decide what to do.
+void UpdateCheckAction::ReceivedBytes(HttpFetcher *fetcher,
+ const char* bytes,
+ int length) {
+ response_buffer_.reserve(response_buffer_.size() + length);
+ response_buffer_.insert(response_buffer_.end(), bytes, bytes + length);
+}
+
+namespace {
+// A little object to call ActionComplete on the ActionProcessor when
+// it's destructed.
+class ScopedActionCompleter {
+ public:
+ explicit ScopedActionCompleter(ActionProcessor* processor,
+ AbstractAction* action)
+ : processor_(processor), action_(action), success_(false) {}
+ ~ScopedActionCompleter() {
+ processor_->ActionComplete(action_, success_);
+ }
+ void set_success(bool success) {
+ success_ = success;
+ }
+ private:
+ ActionProcessor* processor_;
+ AbstractAction* action_;
+ bool success_;
+ DISALLOW_COPY_AND_ASSIGN(ScopedActionCompleter);
+};
+
+// If non-NULL response, caller is responsible for calling xmlXPathFreeObject()
+// on the returned object.
+// This code is roughly based on the libxml tutorial at:
+// http://xmlsoft.org/tutorial/apd.html
+xmlXPathObject* GetNodeSet(xmlDoc* doc, const xmlChar* xpath,
+ const xmlChar* ns, const xmlChar* ns_url) {
+ xmlXPathObject* result = NULL;
+
+ scoped_ptr_malloc<xmlXPathContext, ScopedPtrXmlXPathContextFree> context(
+ xmlXPathNewContext(doc));
+ if (!context.get()) {
+ LOG(ERROR) << "xmlXPathNewContext() returned NULL";
+ return NULL;
+ }
+ if (xmlXPathRegisterNs(context.get(), ns, ns_url) < 0) {
+ LOG(ERROR) << "xmlXPathRegisterNs() returned error";
+ return NULL;
+ }
+
+ result = xmlXPathEvalExpression(xpath, context.get());
+
+ if (result == NULL) {
+ LOG(ERROR) << "xmlXPathEvalExpression returned error";
+ return NULL;
+ }
+ if(xmlXPathNodeSetIsEmpty(result->nodesetval)){
+ LOG(INFO) << "xpath not found in doc";
+ xmlXPathFreeObject(result);
+ return NULL;
+ }
+ return result;
+}
+
+// Returns the string value of a named attribute on a node, or empty string
+// if no such node exists. If the attribute exists and has a value of
+// empty string, there's no way to distinguish that from the attribute
+// not existing.
+string XmlGetProperty(xmlNode* node, const char* name) {
+ if (!xmlHasProp(node, ConstXMLStr(name)))
+ return "";
+ scoped_ptr_malloc<xmlChar, ScopedPtrXmlFree> str(
+ xmlGetProp(node, ConstXMLStr(name)));
+ string ret(reinterpret_cast<const char *>(str.get()));
+ return ret;
+}
+
+// Parses a 64 bit base-10 int from a string and returns it. Returns 0
+// on error. If the string contains "0", that's indistinguishable from
+// error.
+off_t ParseInt(const string& str) {
+ off_t ret = 0;
+
+ int rc = sscanf(str.c_str(), "%lld", &ret);
+ if (rc < 1) {
+ // failure
+ return 0;
+ }
+ return ret;
+}
+} // namespace {}
+
+// If the transfer was successful, this uses libxml2 to parse the response
+// and fill in the appropriate fields of the output object. Also, notifies
+// the processor that we're done.
+void UpdateCheckAction::TransferComplete(HttpFetcher *fetcher,
+ bool successful) {
+ ScopedActionCompleter completer(processor_, this);
+ if (!successful)
+ return;
+ if (!HasOutputPipe()) {
+ // Just set success to whether or not the http transfer succeeded,
+ // which must be true at this point in the code.
+ completer.set_success(true);
+ return;
+ }
+
+ // parse our response and fill the fields in the output object
+ scoped_ptr_malloc<xmlDoc, ScopedPtrXmlDocFree> doc(
+ xmlParseMemory(&response_buffer_[0], response_buffer_.size()));
+ if (!doc.get()) {
+ LOG(ERROR) << "Omaha response not valid XML";
+ return;
+ }
+
+ static const char* kNamespace("x");
+ static const char* kUpdatecheckNodeXpath("/x:gupdate/x:app/x:updatecheck");
+ static const char* kNsUrl("http://www.google.com/update2/response");
+
+ scoped_ptr_malloc<xmlXPathObject, ScopedPtrXmlXPathObjectFree>
+ xpath_nodeset(GetNodeSet(doc.get(),
+ ConstXMLStr(kUpdatecheckNodeXpath),
+ ConstXMLStr(kNamespace),
+ ConstXMLStr(kNsUrl)));
+ if (!xpath_nodeset.get()) {
+ return;
+ }
+ xmlNodeSet* nodeset = xpath_nodeset->nodesetval;
+ CHECK(nodeset) << "XPath missing NodeSet";
+ CHECK_GE(nodeset->nodeNr, 1);
+
+ xmlNode* updatecheck_node = nodeset->nodeTab[0];
+ // get status
+ if (!xmlHasProp(updatecheck_node, ConstXMLStr("status"))) {
+ LOG(ERROR) << "Response missing status";
+ return;
+ }
+
+ const string status(XmlGetProperty(updatecheck_node, "status"));
+ UpdateCheckResponse output_object;
+ if (status == "noupdate") {
+ LOG(INFO) << "No update.";
+ output_object.update_exists = false;
+ SetOutputObject(output_object);
+ completer.set_success(true);
+ return;
+ }
+
+ if (status != "ok") {
+ LOG(ERROR) << "Unknown status: " << status;
+ return;
+ }
+
+ // In best-effort fashion, fetch the rest of the expected attributes
+ // from the updatecheck node, then return the object
+ output_object.update_exists = true;
+ completer.set_success(true);
+
+ output_object.display_version =
+ XmlGetProperty(updatecheck_node, "DisplayVersion");
+ output_object.codebase = XmlGetProperty(updatecheck_node, "codebase");
+ output_object.more_info_url = XmlGetProperty(updatecheck_node, "MoreInfo");
+ output_object.hash = XmlGetProperty(updatecheck_node, "hash");
+ output_object.size = ParseInt(XmlGetProperty(updatecheck_node, "size"));
+ output_object.needs_admin =
+ XmlGetProperty(updatecheck_node, "needsadmin") == "true";
+ output_object.prompt = XmlGetProperty(updatecheck_node, "Prompt") == "true";
+ SetOutputObject(output_object);
+ return;
+}
+
+}; // namespace chromeos_update_engine