crash-reporter: Create a list_proxies command

get_proxies.cc

+// Copyright (c) 2011 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 <string.h>
+#include <unistd.h>
+
+#include <deque>
+#include <string>
+
+#include <dbus/dbus-glib-lowlevel.h>
+#include <glib.h>
+
+#include "base/command_line.h"
+#include "base/file_util.h"
+#include "base/json/json_reader.h"
+#include "base/string_tokenizer.h"
+#include "base/string_util.h"
+#include "base/values.h"
+#include "chromeos/dbus/dbus.h"
+#include "chromeos/syslog_logging.h"
+#include "gflags/gflags.h"
+
+
+#pragma GCC diagnostic ignored "-Wstrict-aliasing"
+DEFINE_bool(force_browser_proxies, false, "Force printing the list of "
+                                          "browser proxies");
+DEFINE_bool(force_session_proxies, false, "Force printing the list of "
+                                          "session proxies");
+DEFINE_bool(quiet, false, "Only print the proxies");
+DEFINE_bool(verbose, false, "Print additional messages even "
+                            "when not run from a TTY");
+#pragma GCC diagnostic error "-Wstrict-aliasing"
+
+
+const char kNoProxy[] = "direct://";
+
+// For ShowBrowserProxies()
+const char kLibCrosServiceName[] = "org.chromium.LibCrosService";
+const char kLibCrosServicePath[] = "/org/chromium/LibCrosService";
+const char kLibCrosServiceInterface[] = "org.chromium.LibCrosServiceInterface";

[kmixter1, 2011/04/06 04:28:53]

Sort these if there is no specific sequence?

[Michael Krebs, 2011/04/12 00:53:38]

They're in top-down order.  You contact the service name, with a path, on an
interface, using a specific method.  The last two are actually opposite to this,
for some reason.

I've reordered the last two, and added a couple comments.  If you'd rather I
sort them, though, that's perfectly fine by me.

[kmixter1, 2011/04/12 01:17:41]

I'd go for abc order, to simplify adding new constants in the future - otherwise
new sections need to be created for all string constants.

[Michael Krebs, 2011/04/13 02:40:24]

Done.

+const char kLibCrosServiceResolveNetworkProxyMethodName[] =
+    "ResolveNetworkProxy";
+const char kLibCrosProxyResolveName[] = "ProxyResolved";
+const char kLibCrosProxyResolveSignalInterface[] =
+    "org.chromium.CrashReporterLibcrosProxyResolvedInterface";
+
+// For ShowSessionProxies()
+const char kSessionManagerService[] = "org.chromium.SessionManager";
+const char kSessionManagerPath[] = "/org/chromium/SessionManager";
+const char kSessionManagerInterface[] = "org.chromium.SessionManagerInterface";
+const char kSessionManagerRetrievePropertyMethod[] = "RetrieveProperty";
+const char kSessionManagerProxySettingsKey[] = "cros.proxy.everywhere";
+
+
+// Number of seconds to wait for browser to send us a signal
+const int kBrowserTimeout = 5;
+
+
+static const char* GetGErrorMessage(const GError* error) {

[kmixter1, 2011/04/06 04:28:53]

consistently use space-star not star-space here and elsewhere

[Michael Krebs, 2011/04/12 00:53:38]

Done.

+  if (!error)
+    return "Unknown error.";
+  return error->message;
+}
+
+
+// Copied from src/update_engine/chrome_browser_proxy_resolver.cc

[kmixter1, 2011/04/12 01:17:41]

1 line between functions

[Michael Krebs, 2011/04/13 02:40:24]

Done.

+std::deque<std::string> ParseProxyString(const std::string &input) {
+  std::deque<std::string> ret;
+  // Some of this code taken from
+  // http://src.chromium.org/svn/trunk/src/net/proxy/proxy_server.cc and
+  // http://src.chromium.org/svn/trunk/src/net/proxy/proxy_list.cc
+  StringTokenizer entry_tok(input, ";");
+  while (entry_tok.GetNext()) {
+    std::string token = entry_tok.token();
+    TrimWhitespaceASCII(token, TRIM_ALL, &token);
+
+    // Start by finding the first space (if any).
+    std::string::iterator space;
+    for (space = token.begin(); space != token.end(); ++space) {
+      if (IsAsciiWhitespace(*space)) {
+        break;
+      }
+    }
+
+    std::string scheme = std::string(token.begin(), space);
+    StringToLowerASCII(&scheme);
+    // Chrome uses "socks" to mean socks4 and "proxy" to mean http.
+    if (scheme == "socks")
+      scheme += "4";
+    else if (scheme == "proxy")
+      scheme = "http";
+    else if (scheme != "https" &&
+             scheme != "socks4" &&
+             scheme != "socks5" &&
+             scheme != "direct")
+      continue;  // Invalid proxy scheme
+
+    std::string host_and_port = std::string(space, token.end());
+    TrimWhitespaceASCII(host_and_port, TRIM_ALL, &host_and_port);
+    if (scheme != "direct" && host_and_port.empty())
+      continue;  // Must supply host/port when non-direct proxy used.
+    ret.push_back(scheme + "://" + host_and_port);
+  }
+  if (ret.empty() || *ret.rbegin() != kNoProxy)
+    ret.push_back(kNoProxy);
+  return ret;
+}
+
+class BrowserProxyResolvedSignalWatcher : public chromeos::dbus::SignalWatcher {

[kmixter1, 2011/04/12 01:17:41]

Add comment describing purpose of class.

[Michael Krebs, 2011/04/13 02:40:24]

Done.

+ public:
+  explicit BrowserProxyResolvedSignalWatcher(GMainLoop *main_loop,
+                                             std::deque<std::string> *proxies)
+      : main_loop_(main_loop), proxies_(proxies) { }
+
+  virtual void OnSignal(DBusMessage *message) {
+    // Get args
+    char *source_url = NULL;
+    char *proxy_list = NULL;
+    char *error = NULL;
+    DBusError arg_error;
+    dbus_error_init(&arg_error);
+    if (!dbus_message_get_args(message, &arg_error,
+                               DBUS_TYPE_STRING, &source_url,
+                               DBUS_TYPE_STRING, &proxy_list,
+                               DBUS_TYPE_STRING, &error,
+                               DBUS_TYPE_INVALID)) {
+      LOG(ERROR) << "Error reading D-Bus signal";
+      return;
+    }
+    if (!source_url || !proxy_list) {
+      LOG(ERROR) << "Error getting url, proxy list from D-Bus signal";
+      return;
+    }
+
+    const std::deque<std::string> &proxies = ParseProxyString(proxy_list);
+    for (std::deque<std::string>::const_iterator it = proxies.begin();
+         it != proxies.end(); ++it) {
+      LOG(INFO) << "Found proxy via browser signal: " << (*it).c_str();
+      proxies_->push_back(*it);
+    }
+
+    g_main_loop_quit(main_loop_);
+  }
+
+ private:
+  GMainLoop *main_loop_;
+  std::deque<std::string> *proxies_;
+};
+
+static gboolean HandleBrowserTimeout(void *data) {
+  GMainLoop *main_loop = reinterpret_cast<GMainLoop *>(data);
+  LOG(ERROR) << "Timeout while waiting for browser to resolve proxy";
+  g_main_loop_quit(main_loop);
+  return false;  // only call once
+}
+
+static bool ShowBrowserProxies(const char *url) {
+  GMainLoop *main_loop = g_main_loop_new(NULL, false);
+
+  chromeos::dbus::BusConnection dbus = chromeos::dbus::GetSystemBusConnection();
+  if (!dbus.HasConnection()) {
+    LOG(ERROR) << "Error connecting to system D-Bus";
+    return false;
+  }
+  chromeos::dbus::Proxy browser_proxy(dbus,
+                                      kLibCrosServiceName,
+                                      kLibCrosServicePath,
+                                      kLibCrosServiceInterface);
+  if (!browser_proxy) {
+    LOG(ERROR) << "Error creating D-Bus proxy to interface "
+               << "'" << kLibCrosServiceName << "'";
+    return false;
+  }
+
+  // Watch for a proxy-resolved signal sent to us
+  std::deque<std::string> proxies;
+  BrowserProxyResolvedSignalWatcher proxy_resolver(main_loop, &proxies);
+  proxy_resolver.StartMonitoring(kLibCrosProxyResolveSignalInterface,
+                                 kLibCrosProxyResolveName);
+
+  // Request the proxies for our URL.  The answer is sent to us via a
+  // proxy-resolved signal.
+  GError *gerror = NULL;
+  if (!dbus_g_proxy_call(browser_proxy.gproxy(),
+                         kLibCrosServiceResolveNetworkProxyMethodName,
+                         &gerror,
+                         G_TYPE_STRING, url,
+                         G_TYPE_STRING, kLibCrosProxyResolveSignalInterface,
+                         G_TYPE_STRING, kLibCrosProxyResolveName,
+                         G_TYPE_INVALID, G_TYPE_INVALID)) {
+    LOG(ERROR) << "Error performing D-Bus proxy call "
+               << "'" << kLibCrosServiceResolveNetworkProxyMethodName << "'"
+               << ": " << GetGErrorMessage(gerror);
+    return false;
+  }
+
+  // Setup a timeout in case the browser doesn't respond with our signal
+  g_timeout_add_seconds(kBrowserTimeout, &HandleBrowserTimeout, main_loop);
+
+  // Loop until we either get the proxy-resolved signal, or until the
+  // timeout is reached.
+  g_main_loop_run(main_loop);
+
+  for (std::deque<std::string>::const_iterator it = proxies.begin();
+       it != proxies.end(); ++it) {
+    g_print("%s\n", (*it).c_str());
+  }
+
+  return true;
+}
+
+
+namespace {
+enum ProxyMode {
+  kProxyModeDirect = 0,
+  kProxyModeAutoDetect = 1,
+  kProxyModePACScript = 2,
+  kProxyModeSingle = 3,
+  kProxyModeProxyPerScheme = 4
+};
+}  // namespace {}
+
+// Returns the scheme portion of a URL.
+const char *GetUrlScheme(const char *url) {
+  const char *ptr;
+  // An undefined URL or scheme defaults to "http://".
+  if (!url || !(ptr = strstr(url, "://")))
+    return strdup("http");
+  return strndup(url, ptr - url);
+}
+
+const char *GetProtocolPathFromScheme(const char *scheme) {
+  if (!strcasecmp(scheme, "http"))
+    return strdup("http.server");
+  if (!strcasecmp(scheme, "https"))
+    return strdup("https.server");
+  return NULL;
+}
+
+// Given a JSON string from the Session Manager describing the session's
+// proxies, set "out_proxies" to the appropriate proxies for a given "url".
+// Copied from src/update_engine/chrome_proxy_resolver.cc.
+static bool GetProxiesFromJsonSettings(const char *url,
+                                       const char *settings,
+                                       std::deque<std::string> *out_proxies) {
+  base::JSONReader parser;
+
+  out_proxies->clear();
+
+  scoped_ptr<Value> root(
+      parser.JsonToValue(settings,
+                         true,  // check root is obj/arr
+                         false));  // false = disallow trailing comma
+  if (!root.get()) {
+    LOG(ERROR) << "Unable to parse JSON: " << parser.GetErrorMessage().c_str();
+    return false;
+  }
+
+  if (!root->IsType(Value::TYPE_DICTIONARY)) {
+    LOG(ERROR) << "Invalid root JSON type";
+    return false;
+  }
+
+  DictionaryValue* root_dict = dynamic_cast<DictionaryValue*>(root.get());
+  if (!root_dict) {
+    LOG(ERROR) << "Expected a DictionaryValue";
+    return false;
+  }
+  int mode = -1;
+  if (!root_dict->GetInteger("mode", &mode)) {
+    LOG(ERROR) << "Error parsing \"mode\" attribute";
+    return false;
+  }
+
+  // TODO(mkrebs): This ignores any "bypass_rules" setting.

[kmixter1, 2011/04/06 04:28:53]

Not sure what is to be done based on this TODO.

[Michael Krebs, 2011/04/12 00:53:38]

Moot now, because I removed the Session Manager proxy stuff per your comment
below.

+  switch (mode) {
+    case kProxyModeDirect: {
+      // Do nothing.
+      break;
+    }
+
+    case kProxyModeSingle: {
+      LOG(INFO) << "single proxy mode";
+      std::string proxy_string;
+      if (!root_dict->GetString("single.server", &proxy_string)) {
+        LOG(ERROR) << "Unable to find \"single.server\" key in "
+                   << "session manager proxy message";
+        return false;
+      }
+      if (proxy_string.find("://") == std::string::npos) {
+        // missing protocol, assume http.
+        proxy_string = std::string("http://") + proxy_string;
+      }
+      LOG(INFO) << "Found proxy via session manager: " << (*out_proxies)[0];
+      out_proxies->push_back(proxy_string);
+      break;
+    }
+
+    case kProxyModeProxyPerScheme: {
+      // Proxy per scheme mode.
+      LOG(INFO) << "proxy per scheme mode";
+
+      // Using "proto_*" variables to refer to http or https.
+      const char *scheme = GetUrlScheme(url);
+      const char *proto_path = GetProtocolPathFromScheme(scheme);
+      free(const_cast<char *>(scheme));
+      if (!proto_path) {
+        LOG(ERROR) << "Unknown scheme '" << scheme
+                   << "' for URL '" << url << "'";
+        return false;
+      }
+      const char *socks_path = "socks.server";
+
+      std::string proto_server, socks_server;
+      if (root_dict->GetString(proto_path, &proto_server)) {
+        if (proto_server.find("://") == std::string::npos) {
+          // missing protocol, assume http.
+          proto_server = std::string("http://") + proto_server;
+        }
+        out_proxies->push_back(proto_server);
+        LOG(INFO) << "got http/https server: " << proto_server;
+      }
+      if (root_dict->GetString(socks_path, &socks_server)) {
+        out_proxies->push_back(socks_server);
+        LOG(INFO) << "got socks server: " << proto_server;
+      }
+
+      free(const_cast<char *>(proto_path));
+      break;
+    }
+
+    default: {
+      LOG(INFO) << "unsupported proxy mode: " << mode;
+      break;
+    }
+  }
+
+  // Always add direct proxy.
+  out_proxies->push_back(kNoProxy);
+  return true;
+}
+
+static bool ShowSessionProxies(const char *url) {
+  chromeos::dbus::BusConnection dbus = chromeos::dbus::GetSystemBusConnection();
+  if (!dbus.HasConnection()) {
+    LOG(ERROR) << "Error connecting to system D-Bus";
+    return false;
+  }
+  chromeos::dbus::Proxy session_proxy(dbus,
+                                      kSessionManagerService,
+                                      kSessionManagerPath,
+                                      kSessionManagerInterface);
+  if (!session_proxy) {
+    LOG(ERROR) << "Error creating D-Bus proxy to interface "
+               << "'" << kSessionManagerInterface << "'";
+    return false;
+  }
+
+  // First, query dbus for the currently stored settings.
+  gchar *json_settings = NULL;
+  GError *gerror = NULL;
+  GArray *sig = NULL;
+  if (!dbus_g_proxy_call(session_proxy.gproxy(),
+                      kSessionManagerRetrievePropertyMethod,
+                      &gerror,
+                      G_TYPE_STRING, kSessionManagerProxySettingsKey,
+                      G_TYPE_INVALID,
+                      G_TYPE_STRING, &json_settings,
+                      DBUS_TYPE_G_UCHAR_ARRAY, &sig,
+                      G_TYPE_INVALID)) {
+    LOG(ERROR) << "Error retrieving proxy settings via D-Bus proxy call: "
+               << GetGErrorMessage(gerror);
+    return false;
+  }
+  g_array_free(sig, false);
+  LOG(INFO) << "Received session manager proxy settings: " << json_settings;
+
+  std::deque<std::string> proxies;
+  if (!GetProxiesFromJsonSettings(url, json_settings, &proxies))
+    LOG(ERROR) << "Error parsing JSON '" << json_settings << "'";
+  g_free(json_settings);
+
+  for (std::deque<std::string>::const_iterator it = proxies.begin();
+       it != proxies.end(); ++it) {
+    g_print("%s\n", (*it).c_str());
+  }
+  return true;
+}
+
+
+int main(int argc, char *argv[]) {
+  google::ParseCommandLineFlags(&argc, &argv, true);
+  CommandLine::Init(argc, argv);
+
+  // Default to logging to syslog.
+  int init_flags = chromeos::kLogToSyslog;
+  // Log to stderr if a TTY (and "-quiet" wasn't passed), or if "-verbose"
+  // was passed.
+  if ((!FLAGS_quiet && isatty(STDERR_FILENO)) || FLAGS_verbose)
+    init_flags |= chromeos::kLogToStderr;
+  chromeos::InitLog(init_flags);
+
+  ::g_type_init();
+
+  const char *url = (argc >= 2) ? argv[1] : NULL;
+
+  LOG(INFO) << "Resolving proxies for URL: " << (url ? url : "<n/a>");
+
+  if (FLAGS_force_browser_proxies || FLAGS_force_session_proxies) {
+    if (FLAGS_force_browser_proxies) {
+      if (!ShowBrowserProxies(url))
+        LOG(ERROR) << "Error resolving proxies via the browser";
+    }
+    if (FLAGS_force_session_proxies) {
+      if (!ShowSessionProxies(url))
+        LOG(ERROR) << "Error resolving proxies via the session manager";
+    }
+  } else {
+    if (!ShowBrowserProxies(url)) {
+      LOG(ERROR) << "Error resolving proxies via the browser";
+      if (!ShowSessionProxies(url)) {

[kmixter1, 2011/04/06 04:28:53]

I've heard we're moving away from global proxy settings.  You should check with
cmasone on this.  If so, I'd rather not add the complexity to this code to query
session_manager on its idea of proxy when the chrome request times out.

[Michael Krebs, 2011/04/12 00:53:38]

Removed.

+        LOG(ERROR) << "Error resolving proxies via the session manager";
+        LOG(INFO) << "Assuming direct proxy";
+        g_print("%s\n", kNoProxy);
+      }
+    }
+  }
+
+  return 0;
+}