import FIREFOX_52_6_0esr_RELEASE from mozilla-esr52 hg repo

widget/xremoteclient/XRemoteClient.cpp

@@ -0,0 +1,805 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim:expandtab:shiftwidth=2:tabstop=8:
+ */
+/* vim:set ts=8 sw=2 et cindent: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "mozilla/ArrayUtils.h"
+#include "mozilla/Sprintf.h"
+#include "XRemoteClient.h"
+#include "prmem.h"
+#include "plstr.h"
+#include "prsystem.h"
+#include "mozilla/Logging.h"
+#include "prenv.h"
+#include "prdtoa.h"
+#include <stdlib.h>
+#include <unistd.h>
+#include <string.h>
+#include <strings.h>
+#include <sys/time.h>
+#include <sys/types.h>
+#include <unistd.h>
+#include <limits.h>
+#include <X11/Xatom.h>
+
+#define MOZILLA_VERSION_PROP   "_MOZILLA_VERSION"
+#define MOZILLA_LOCK_PROP      "_MOZILLA_LOCK"
+#define MOZILLA_COMMANDLINE_PROP "_MOZILLA_COMMANDLINE"
+#define MOZILLA_RESPONSE_PROP  "_MOZILLA_RESPONSE"
+#define MOZILLA_USER_PROP      "_MOZILLA_USER"
+#define MOZILLA_PROFILE_PROP   "_MOZILLA_PROFILE"
+#define MOZILLA_PROGRAM_PROP   "_MOZILLA_PROGRAM"
+
+#ifdef IS_BIG_ENDIAN
+#define TO_LITTLE_ENDIAN32(x) \
+    ((((x) & 0xff000000) >> 24) | (((x) & 0x00ff0000) >> 8) | \
+    (((x) & 0x0000ff00) << 8) | (((x) & 0x000000ff) << 24))
+#else
+#define TO_LITTLE_ENDIAN32(x) (x)
+#endif
+    
+#ifndef MAX_PATH
+#ifdef PATH_MAX
+#define MAX_PATH PATH_MAX
+#else
+#define MAX_PATH 1024
+#endif
+#endif
+
+using mozilla::LogLevel;
+
+static PRLogModuleInfo *sRemoteLm = nullptr;
+
+static int (*sOldHandler)(Display *, XErrorEvent *);
+static bool sGotBadWindow;
+
+XRemoteClient::XRemoteClient()
+{
+  mDisplay = 0;
+  mInitialized = false;
+  mMozVersionAtom = 0;
+  mMozLockAtom = 0;
+  mMozCommandLineAtom = 0;
+  mMozResponseAtom = 0;
+  mMozWMStateAtom = 0;
+  mMozUserAtom = 0;
+  mMozProfileAtom = 0;
+  mMozProgramAtom = 0;
+  mLockData = 0;
+  if (!sRemoteLm)
+    sRemoteLm = PR_NewLogModule("XRemoteClient");
+  MOZ_LOG(sRemoteLm, LogLevel::Debug, ("XRemoteClient::XRemoteClient"));
+}
+
+XRemoteClient::~XRemoteClient()
+{
+  MOZ_LOG(sRemoteLm, LogLevel::Debug, ("XRemoteClient::~XRemoteClient"));
+  if (mInitialized)
+    Shutdown();
+}
+
+// Minimize the roundtrips to the X-server
+static const char *XAtomNames[] = {
+  MOZILLA_VERSION_PROP,
+  MOZILLA_LOCK_PROP,
+  MOZILLA_RESPONSE_PROP,
+  "WM_STATE",
+  MOZILLA_USER_PROP,
+  MOZILLA_PROFILE_PROP,
+  MOZILLA_PROGRAM_PROP,
+  MOZILLA_COMMANDLINE_PROP
+};
+static Atom XAtoms[MOZ_ARRAY_LENGTH(XAtomNames)];
+
+nsresult
+XRemoteClient::Init()
+{
+  MOZ_LOG(sRemoteLm, LogLevel::Debug, ("XRemoteClient::Init"));
+
+  if (mInitialized)
+    return NS_OK;
+
+  // try to open the display
+  mDisplay = XOpenDisplay(0);
+  if (!mDisplay)
+    return NS_ERROR_FAILURE;
+
+  // get our atoms
+  XInternAtoms(mDisplay, const_cast<char**>(XAtomNames),
+               MOZ_ARRAY_LENGTH(XAtomNames), False, XAtoms);
+
+  int i = 0;
+  mMozVersionAtom  = XAtoms[i++];
+  mMozLockAtom     = XAtoms[i++];
+  mMozResponseAtom = XAtoms[i++];
+  mMozWMStateAtom  = XAtoms[i++];
+  mMozUserAtom     = XAtoms[i++];
+  mMozProfileAtom  = XAtoms[i++];
+  mMozProgramAtom  = XAtoms[i++];
+  mMozCommandLineAtom = XAtoms[i++];
+
+  mInitialized = true;
+
+  return NS_OK;
+}
+
+void
+XRemoteClient::Shutdown (void)
+{
+  MOZ_LOG(sRemoteLm, LogLevel::Debug, ("XRemoteClient::Shutdown"));
+
+  if (!mInitialized)
+    return;
+
+  // shut everything down
+  XCloseDisplay(mDisplay);
+  mDisplay = 0;
+  mInitialized = false;
+  if (mLockData) {
+    free(mLockData);
+    mLockData = 0;
+  }
+}
+
+static int
+HandleBadWindow(Display *display, XErrorEvent *event)
+{
+  if (event->error_code == BadWindow) {
+    sGotBadWindow = true;
+    return 0; // ignored
+  }
+  else {
+    return (*sOldHandler)(display, event);
+  }
+}
+
+nsresult
+XRemoteClient::SendCommandLine (const char *aProgram, const char *aUsername,
+                                const char *aProfile,
+                                int32_t argc, char **argv,
+                                const char* aDesktopStartupID,
+                                char **aResponse, bool *aWindowFound)
+{
+  MOZ_LOG(sRemoteLm, LogLevel::Debug, ("XRemoteClient::SendCommandLine"));
+
+  *aWindowFound = false;
+
+  // FindBestWindow() iterates down the window hierarchy, so catch X errors
+  // when windows get destroyed before being accessed.
+  sOldHandler = XSetErrorHandler(HandleBadWindow);
+
+  Window w = FindBestWindow(aProgram, aUsername, aProfile);
+
+  nsresult rv = NS_OK;
+
+  if (w) {
+    // ok, let the caller know that we at least found a window.
+    *aWindowFound = true;
+
+    // Ignore BadWindow errors up to this point.  The last request from
+    // FindBestWindow() was a synchronous XGetWindowProperty(), so no need to
+    // Sync.  Leave the error handler installed to detect if w gets destroyed.
+    sGotBadWindow = false;
+
+    // make sure we get the right events on that window
+    XSelectInput(mDisplay, w,
+                 (PropertyChangeMask|StructureNotifyMask));
+
+    bool destroyed = false;
+
+    // get the lock on the window
+    rv = GetLock(w, &destroyed);
+
+    if (NS_SUCCEEDED(rv)) {
+      // send our command
+      rv = DoSendCommandLine(w, argc, argv, aDesktopStartupID, aResponse,
+                             &destroyed);
+
+      // if the window was destroyed, don't bother trying to free the
+      // lock.
+      if (!destroyed)
+          FreeLock(w); // doesn't really matter what this returns
+
+    }
+  }
+
+  XSetErrorHandler(sOldHandler);
+
+  MOZ_LOG(sRemoteLm, LogLevel::Debug, ("SendCommandInternal returning 0x%x\n", rv));
+
+  return rv;
+}
+
+Window
+XRemoteClient::CheckWindow(Window aWindow)
+{
+  Atom type = None;
+  int  format;
+  unsigned long nitems, bytesafter;
+  unsigned char *data;
+  Window innerWindow;
+
+  XGetWindowProperty(mDisplay, aWindow, mMozWMStateAtom,
+		     0, 0, False, AnyPropertyType,
+		     &type, &format, &nitems, &bytesafter, &data);
+
+  if (type) {
+    XFree(data);
+    return aWindow;
+  }
+
+  // didn't find it here so check the children of this window
+  innerWindow = CheckChildren(aWindow);
+
+  if (innerWindow)
+    return innerWindow;
+
+  return aWindow;
+}
+
+Window
+XRemoteClient::CheckChildren(Window aWindow)
+{
+  Window root, parent;
+  Window *children;
+  unsigned int nchildren;
+  unsigned int i;
+  Atom type = None;
+  int format;
+  unsigned long nitems, after;
+  unsigned char *data;
+  Window retval = None;
+  
+  if (!XQueryTree(mDisplay, aWindow, &root, &parent, &children,
+		  &nchildren))
+    return None;
+  
+  // scan the list first before recursing into the list of windows
+  // which can get quite deep.
+  for (i=0; !retval && (i < nchildren); i++) {
+    XGetWindowProperty(mDisplay, children[i], mMozWMStateAtom,
+		       0, 0, False, AnyPropertyType, &type, &format,
+		       &nitems, &after, &data);
+    if (type) {
+      XFree(data);
+      retval = children[i];
+    }
+  }
+
+  // otherwise recurse into the list
+  for (i=0; !retval && (i < nchildren); i++) {
+    retval = CheckChildren(children[i]);
+  }
+
+  if (children)
+    XFree((char *)children);
+
+  return retval;
+}
+
+nsresult
+XRemoteClient::GetLock(Window aWindow, bool *aDestroyed)
+{
+  bool locked = false;
+  bool waited = false;
+  *aDestroyed = false;
+
+  nsresult rv = NS_OK;
+
+  if (!mLockData) {
+    
+    char pidstr[32];
+    char sysinfobuf[SYS_INFO_BUFFER_LENGTH];
+    SprintfLiteral(pidstr, "pid%d@", getpid());
+    PRStatus status;
+    status = PR_GetSystemInfo(PR_SI_HOSTNAME, sysinfobuf,
+			      SYS_INFO_BUFFER_LENGTH);
+    if (status != PR_SUCCESS) {
+      return NS_ERROR_FAILURE;
+    }
+    
+    // allocate enough space for the string plus the terminating
+    // char
+    mLockData = (char *)malloc(strlen(pidstr) + strlen(sysinfobuf) + 1);
+    if (!mLockData)
+      return NS_ERROR_OUT_OF_MEMORY;
+
+    strcpy(mLockData, pidstr);
+    if (!strcat(mLockData, sysinfobuf))
+      return NS_ERROR_FAILURE;
+  }
+
+  do {
+    int result;
+    Atom actual_type;
+    int actual_format;
+    unsigned long nitems, bytes_after;
+    unsigned char *data = 0;
+
+    XGrabServer(mDisplay);
+
+    result = XGetWindowProperty (mDisplay, aWindow, mMozLockAtom,
+				 0, (65536 / sizeof (long)),
+				 False, /* don't delete */
+				 XA_STRING,
+				 &actual_type, &actual_format,
+				 &nitems, &bytes_after,
+				 &data);
+
+    // aWindow may have been destroyed before XSelectInput was processed, in
+    // which case there may not be any DestroyNotify event in the queue to
+    // tell us.  XGetWindowProperty() was synchronous so error responses have
+    // now been processed, setting sGotBadWindow.
+    if (sGotBadWindow) {
+      *aDestroyed = true;
+      rv = NS_ERROR_FAILURE;
+    }
+    else if (result != Success || actual_type == None) {
+      /* It's not now locked - lock it. */
+      XChangeProperty (mDisplay, aWindow, mMozLockAtom, XA_STRING, 8,
+		       PropModeReplace,
+		       (unsigned char *)mLockData,
+		       strlen(mLockData));
+      locked = True;
+    }
+
+    XUngrabServer(mDisplay);
+    XFlush(mDisplay); // ungrab now!
+
+    if (!locked && !NS_FAILED(rv)) {
+      /* We tried to grab the lock this time, and failed because someone
+	 else is holding it already.  So, wait for a PropertyDelete event
+	 to come in, and try again. */
+      MOZ_LOG(sRemoteLm, LogLevel::Debug, 
+	     ("window 0x%x is locked by %s; waiting...\n",
+	      (unsigned int) aWindow, data));
+      waited = True;
+      while (1) {
+	XEvent event;
+	int select_retval;
+	fd_set select_set;
+	struct timeval delay;
+	delay.tv_sec = 10;
+	delay.tv_usec = 0;
+
+	FD_ZERO(&select_set);
+	// add the x event queue to the select set
+	FD_SET(ConnectionNumber(mDisplay), &select_set);
+	select_retval = select(ConnectionNumber(mDisplay) + 1,
+			       &select_set, nullptr, nullptr, &delay);
+	// did we time out?
+	if (select_retval == 0) {
+	  MOZ_LOG(sRemoteLm, LogLevel::Debug, ("timed out waiting for window\n"));
+          rv = NS_ERROR_FAILURE;
+          break;
+	}
+	MOZ_LOG(sRemoteLm, LogLevel::Debug, ("xevent...\n"));
+	XNextEvent (mDisplay, &event);
+	if (event.xany.type == DestroyNotify &&
+	    event.xdestroywindow.window == aWindow) {
+	  *aDestroyed = true;
+          rv = NS_ERROR_FAILURE;
+          break;
+	}
+	else if (event.xany.type == PropertyNotify &&
+		 event.xproperty.state == PropertyDelete &&
+		 event.xproperty.window == aWindow &&
+		 event.xproperty.atom == mMozLockAtom) {
+	  /* Ok!  Someone deleted their lock, so now we can try
+	     again. */
+	  MOZ_LOG(sRemoteLm, LogLevel::Debug,
+		 ("(0x%x unlocked, trying again...)\n",
+		  (unsigned int) aWindow));
+		  break;
+	}
+      }
+    }
+    if (data)
+      XFree(data);
+  } while (!locked && !NS_FAILED(rv));
+
+  if (waited && locked) {
+    MOZ_LOG(sRemoteLm, LogLevel::Debug, ("obtained lock.\n"));
+  } else if (*aDestroyed) {
+    MOZ_LOG(sRemoteLm, LogLevel::Debug,
+           ("window 0x%x unexpectedly destroyed.\n",
+            (unsigned int) aWindow));
+  }
+
+  return rv;
+}
+
+Window
+XRemoteClient::FindBestWindow(const char *aProgram, const char *aUsername,
+                              const char *aProfile)
+{
+  Window root = RootWindowOfScreen(DefaultScreenOfDisplay(mDisplay));
+  Window bestWindow = 0;
+  Window root2, parent, *kids;
+  unsigned int nkids;
+
+  // Get a list of the children of the root window, walk the list
+  // looking for the best window that fits the criteria.
+  if (!XQueryTree(mDisplay, root, &root2, &parent, &kids, &nkids)) {
+    MOZ_LOG(sRemoteLm, LogLevel::Debug,
+           ("XQueryTree failed in XRemoteClient::FindBestWindow"));
+    return 0;
+  }
+
+  if (!(kids && nkids)) {
+    MOZ_LOG(sRemoteLm, LogLevel::Debug, ("root window has no children"));
+    return 0;
+  }
+
+  // We'll walk the list of windows looking for a window that best
+  // fits the criteria here.
+
+  for (unsigned int i = 0; i < nkids; i++) {
+    Atom type;
+    int format;
+    unsigned long nitems, bytesafter;
+    unsigned char *data_return = 0;
+    Window w;
+    w = kids[i];
+    // find the inner window with WM_STATE on it
+    w = CheckWindow(w);
+
+    int status = XGetWindowProperty(mDisplay, w, mMozVersionAtom,
+                                    0, (65536 / sizeof (long)),
+                                    False, XA_STRING,
+                                    &type, &format, &nitems, &bytesafter,
+                                    &data_return);
+
+    if (!data_return)
+      continue;
+
+    double version = PR_strtod((char*) data_return, nullptr);
+    XFree(data_return);
+
+    if (!(version >= 5.1 && version < 6))
+      continue;
+
+    data_return = 0;
+
+    if (status != Success || type == None)
+      continue;
+
+    // If someone passed in a program name, check it against this one
+    // unless it's "any" in which case, we don't care.  If someone did
+    // pass in a program name and this window doesn't support that
+    // protocol, we don't include it in our list.
+    if (aProgram && strcmp(aProgram, "any")) {
+        status = XGetWindowProperty(mDisplay, w, mMozProgramAtom,
+                                    0, (65536 / sizeof(long)),
+                                    False, XA_STRING,
+                                    &type, &format, &nitems, &bytesafter,
+                                    &data_return);
+        
+        // If the return name is not the same as what someone passed in,
+        // we don't want this window.
+        if (data_return) {
+            if (strcmp(aProgram, (const char *)data_return)) {
+                XFree(data_return);
+                continue;
+            }
+
+            // This is actually the success condition.
+            XFree(data_return);
+        }
+        else {
+            // Doesn't support the protocol, even though the user
+            // requested it.  So we're not going to use this window.
+            continue;
+        }
+    }
+
+    // Check to see if it has the user atom on that window.  If there
+    // is then we need to make sure that it matches what we have.
+    const char *username;
+    if (aUsername) {
+      username = aUsername;
+    }
+    else {
+      username = PR_GetEnv("LOGNAME");
+    }
+
+    if (username) {
+        status = XGetWindowProperty(mDisplay, w, mMozUserAtom,
+                                    0, (65536 / sizeof(long)),
+                                    False, XA_STRING,
+                                    &type, &format, &nitems, &bytesafter,
+                                    &data_return);
+
+        // if there's a username compare it with what we have
+        if (data_return) {
+            // If the IDs aren't equal, we don't want this window.
+            if (strcmp(username, (const char *)data_return)) {
+                XFree(data_return);
+                continue;
+            }
+
+            XFree(data_return);
+        }
+    }
+
+    // Check to see if there's a profile name on this window.  If
+    // there is, then we need to make sure it matches what someone
+    // passed in.
+    if (aProfile) {
+        status = XGetWindowProperty(mDisplay, w, mMozProfileAtom,
+                                    0, (65536 / sizeof(long)),
+                                    False, XA_STRING,
+                                    &type, &format, &nitems, &bytesafter,
+                                    &data_return);
+
+        // If there's a profile compare it with what we have
+        if (data_return) {
+            // If the profiles aren't equal, we don't want this window.
+            if (strcmp(aProfile, (const char *)data_return)) {
+                XFree(data_return);
+                continue;
+            }
+
+            XFree(data_return);
+        }
+    }
+
+    // Check to see if the window supports the new command-line passing
+    // protocol, if that is requested.
+
+    // If we got this far, this is the best window.  It passed
+    // all the tests.
+    bestWindow = w;
+    break;
+  }
+
+  if (kids)
+    XFree((char *) kids);
+
+  return bestWindow;
+}
+
+nsresult
+XRemoteClient::FreeLock(Window aWindow)
+{
+  int result;
+  Atom actual_type;
+  int actual_format;
+  unsigned long nitems, bytes_after;
+  unsigned char *data = 0;
+
+  result = XGetWindowProperty(mDisplay, aWindow, mMozLockAtom,
+                              0, (65536 / sizeof(long)),
+                              True, /* atomic delete after */
+                              XA_STRING,
+                              &actual_type, &actual_format,
+                              &nitems, &bytes_after,
+                              &data);
+  if (result != Success) {
+      MOZ_LOG(sRemoteLm, LogLevel::Debug,
+             ("unable to read and delete " MOZILLA_LOCK_PROP
+              " property\n"));
+      return NS_ERROR_FAILURE;
+  }
+  else if (!data || !*data){
+      MOZ_LOG(sRemoteLm, LogLevel::Debug,
+             ("invalid data on " MOZILLA_LOCK_PROP
+              " of window 0x%x.\n",
+              (unsigned int) aWindow));
+      return NS_ERROR_FAILURE;
+  }
+  else if (strcmp((char *)data, mLockData)) {
+      MOZ_LOG(sRemoteLm, LogLevel::Debug,
+             (MOZILLA_LOCK_PROP " was stolen!  Expected \"%s\", saw \"%s\"!\n",
+              mLockData, data));
+      return NS_ERROR_FAILURE;
+  }
+
+  if (data)
+      XFree(data);
+  return NS_OK;
+}
+
+/* like strcpy, but return the char after the final null */
+static char*
+estrcpy(const char* s, char* d)
+{
+  while (*s)
+    *d++ = *s++;
+
+  *d++ = '\0';
+  return d;
+}
+
+nsresult
+XRemoteClient::DoSendCommandLine(Window aWindow, int32_t argc, char **argv,
+                                 const char* aDesktopStartupID,
+                                 char **aResponse, bool *aDestroyed)
+{
+  *aDestroyed = false;
+
+  char cwdbuf[MAX_PATH];
+  if (!getcwd(cwdbuf, MAX_PATH))
+    return NS_ERROR_UNEXPECTED;
+
+  // the commandline property is constructed as an array of int32_t
+  // followed by a series of null-terminated strings:
+  //
+  // [argc][offsetargv0][offsetargv1...]<workingdir>\0<argv[0]>\0argv[1]...\0
+  // (offset is from the beginning of the buffer)
+
+  static char desktopStartupPrefix[] = " DESKTOP_STARTUP_ID=";
+
+  int32_t argvlen = strlen(cwdbuf);
+  for (int i = 0; i < argc; ++i) {
+    int32_t len = strlen(argv[i]);
+    if (i == 0 && aDesktopStartupID) {
+      len += sizeof(desktopStartupPrefix) - 1 + strlen(aDesktopStartupID);
+    }
+    argvlen += len;
+  }
+
+  int32_t* buffer = (int32_t*) malloc(argvlen + argc + 1 +
+                                      sizeof(int32_t) * (argc + 1));
+  if (!buffer)
+    return NS_ERROR_OUT_OF_MEMORY;
+
+  buffer[0] = TO_LITTLE_ENDIAN32(argc);
+
+  char *bufend = (char*) (buffer + argc + 1);
+
+  bufend = estrcpy(cwdbuf, bufend);
+
+  for (int i = 0; i < argc; ++i) {
+    buffer[i + 1] = TO_LITTLE_ENDIAN32(bufend - ((char*) buffer));
+    bufend = estrcpy(argv[i], bufend);
+    if (i == 0 && aDesktopStartupID) {
+      bufend = estrcpy(desktopStartupPrefix, bufend - 1);
+      bufend = estrcpy(aDesktopStartupID, bufend - 1);
+    }
+  }
+
+#ifdef DEBUG_bsmedberg
+  int32_t   debug_argc   = TO_LITTLE_ENDIAN32(*buffer);
+  char *debug_workingdir = (char*) (buffer + argc + 1);
+
+  printf("Sending command line:\n"
+         "  working dir: %s\n"
+         "  argc:\t%i",
+         debug_workingdir,
+         debug_argc);
+
+  int32_t  *debug_offset = buffer + 1;
+  for (int debug_i = 0; debug_i < debug_argc; ++debug_i)
+    printf("  argv[%i]:\t%s\n", debug_i,
+           ((char*) buffer) + TO_LITTLE_ENDIAN32(debug_offset[debug_i]));
+#endif
+
+  XChangeProperty (mDisplay, aWindow, mMozCommandLineAtom, XA_STRING, 8,
+                   PropModeReplace, (unsigned char *) buffer,
+                   bufend - ((char*) buffer));
+  free(buffer);
+
+  if (!WaitForResponse(aWindow, aResponse, aDestroyed, mMozCommandLineAtom))
+    return NS_ERROR_FAILURE;
+  
+  return NS_OK;
+}
+
+bool
+XRemoteClient::WaitForResponse(Window aWindow, char **aResponse,
+                               bool *aDestroyed, Atom aCommandAtom)
+{
+  bool done = false;
+  bool accepted = false;
+
+  while (!done) {
+    XEvent event;
+    XNextEvent (mDisplay, &event);
+    if (event.xany.type == DestroyNotify &&
+        event.xdestroywindow.window == aWindow) {
+      /* Print to warn user...*/
+      MOZ_LOG(sRemoteLm, LogLevel::Debug,
+             ("window 0x%x was destroyed.\n",
+              (unsigned int) aWindow));
+      *aResponse = strdup("Window was destroyed while reading response.");
+      *aDestroyed = true;
+      return false;
+    }
+    else if (event.xany.type == PropertyNotify &&
+             event.xproperty.state == PropertyNewValue &&
+             event.xproperty.window == aWindow &&
+             event.xproperty.atom == mMozResponseAtom) {
+      Atom actual_type;
+      int actual_format;
+      unsigned long nitems, bytes_after;
+      unsigned char *data = 0;
+      Bool result;
+      result = XGetWindowProperty (mDisplay, aWindow, mMozResponseAtom,
+                                   0, (65536 / sizeof (long)),
+                                   True, /* atomic delete after */
+                                   XA_STRING,
+                                   &actual_type, &actual_format,
+                                   &nitems, &bytes_after,
+                                   &data);
+      if (result != Success) {
+        MOZ_LOG(sRemoteLm, LogLevel::Debug,
+               ("failed reading " MOZILLA_RESPONSE_PROP
+                " from window 0x%0x.\n",
+                (unsigned int) aWindow));
+        *aResponse = strdup("Internal error reading response from window.");
+        done = true;
+      }
+      else if (!data || strlen((char *) data) < 5) {
+        MOZ_LOG(sRemoteLm, LogLevel::Debug,
+               ("invalid data on " MOZILLA_RESPONSE_PROP
+                " property of window 0x%0x.\n",
+                (unsigned int) aWindow));
+        *aResponse = strdup("Server returned invalid data in response.");
+        done = true;
+      }
+      else if (*data == '1') {  /* positive preliminary reply */
+        MOZ_LOG(sRemoteLm, LogLevel::Debug,  ("%s\n", data + 4));
+        /* keep going */
+        done = false;
+      }
+
+      else if (!strncmp ((char *)data, "200", 3)) { /* positive completion */
+        *aResponse = strdup((char *)data);
+        accepted = true;
+        done = true;
+      }
+
+      else if (*data == '2') {  /* positive completion */
+        MOZ_LOG(sRemoteLm, LogLevel::Debug, ("%s\n", data + 4));
+        *aResponse = strdup((char *)data);
+        accepted = true;
+        done = true;
+      }
+
+      else if (*data == '3') {  /* positive intermediate reply */
+        MOZ_LOG(sRemoteLm, LogLevel::Debug,
+               ("internal error: "
+                "server wants more information?  (%s)\n",
+                data));
+        *aResponse = strdup((char *)data);
+        done = true;
+      }
+
+      else if (*data == '4' ||  /* transient negative completion */
+               *data == '5') {  /* permanent negative completion */
+        MOZ_LOG(sRemoteLm, LogLevel::Debug, ("%s\n", data + 4));
+        *aResponse = strdup((char *)data);
+        done = true;
+      }
+
+      else {
+        MOZ_LOG(sRemoteLm, LogLevel::Debug,
+               ("unrecognised " MOZILLA_RESPONSE_PROP
+                " from window 0x%x: %s\n",
+                (unsigned int) aWindow, data));
+        *aResponse = strdup((char *)data);
+        done = true;
+      }
+
+      if (data)
+        XFree(data);
+    }
+
+    else if (event.xany.type == PropertyNotify &&
+             event.xproperty.window == aWindow &&
+             event.xproperty.state == PropertyDelete &&
+             event.xproperty.atom == aCommandAtom) {
+      MOZ_LOG(sRemoteLm, LogLevel::Debug,
+             ("(server 0x%x has accepted "
+              MOZILLA_COMMANDLINE_PROP ".)\n",
+              (unsigned int) aWindow));
+    }
+    
+  }
+
+  return accepted;
+}

widget/xremoteclient/XRemoteClient.h

@@ -0,0 +1,56 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include <X11/X.h>
+#include <X11/Xlib.h>
+
+#include "nsRemoteClient.h"
+
+class XRemoteClient : public nsRemoteClient
+{
+public:
+  XRemoteClient();
+  ~XRemoteClient();
+
+  virtual nsresult Init();
+  virtual nsresult SendCommandLine(const char *aProgram, const char *aUsername,
+                                   const char *aProfile,
+                                   int32_t argc, char **argv,
+                                   const char* aDesktopStartupID,
+                                   char **aResponse, bool *aSucceeded);
+  void Shutdown();
+
+private:
+
+  Window         CheckWindow      (Window aWindow);
+  Window         CheckChildren    (Window aWindow);
+  nsresult       GetLock          (Window aWindow, bool *aDestroyed);
+  nsresult       FreeLock         (Window aWindow);
+  Window         FindBestWindow   (const char *aProgram,
+                                   const char *aUsername,
+                                   const char *aProfile);
+  nsresult       DoSendCommandLine(Window aWindow,
+                                   int32_t argc, char **argv,
+                                   const char* aDesktopStartupID,
+                                   char **aResponse,
+                                   bool *aDestroyed);
+  bool           WaitForResponse  (Window aWindow, char **aResponse,
+                                   bool *aDestroyed, Atom aCommandAtom);
+
+  Display       *mDisplay;
+
+  Atom           mMozVersionAtom;
+  Atom           mMozLockAtom;
+  Atom           mMozCommandLineAtom;
+  Atom           mMozResponseAtom;
+  Atom           mMozWMStateAtom;
+  Atom           mMozUserAtom;
+  Atom           mMozProfileAtom;
+  Atom           mMozProgramAtom;
+
+  char          *mLockData;
+
+  bool           mInitialized;
+};

widget/xremoteclient/moz.build

@@ -0,0 +1,11 @@
+# -*- Mode: python; indent-tabs-mode: nil; tab-width: 40 -*-
+# vim: set filetype=python:
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+FINAL_LIBRARY = 'xul'
+
+SOURCES += [
+    'XRemoteClient.cpp',
+]

widget/xremoteclient/nsRemoteClient.h

@@ -0,0 +1,62 @@
+/* -*- Mode: IDL; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim:expandtab:shiftwidth=4:tabstop=4:
+ */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef nsRemoteClient_h__
+#define nsRemoteClient_h__
+
+#include "nscore.h"
+
+/**
+ * Pure-virtual common base class for remoting implementations.
+ */
+
+class nsRemoteClient
+{
+public:
+  /**
+   * Initializes the client
+   */
+  virtual nsresult Init() = 0;
+
+  /**
+   * Send a complete command line to a running instance.
+   *
+   * @param aProgram This is the preferred program that we want to use
+   * for this particular command.
+   *
+   * @param aUsername This allows someone to only talk to an instance
+   * of the server that's running under a particular username.  If
+   * this isn't specified here it's pulled from the LOGNAME
+   * environmental variable if it's set.
+   *
+   * @param aProfile This allows you to specify a particular server
+   * running under a named profile.  If it is not specified the
+   * profile is not checked.
+   *
+   * @param argc The number of command-line arguments.
+   *
+   * @param argv The command-line arguments.
+   *
+   * @param aDesktopStartupID the contents of the DESKTOP_STARTUP_ID environment
+   * variable defined by the Startup Notification specification
+   * http://standards.freedesktop.org/startup-notification-spec/startup-notification-0.1.txt
+   *
+   * @param aResponse If there is a response, it will be here.  This
+   * includes error messages.  The string is allocated using stdlib
+   * string functions, so free it with free().
+   *
+   * @return true if succeeded, false if no running instance was found.
+   * 
+   */
+  virtual nsresult SendCommandLine(const char *aProgram, const char *aUsername,
+                                   const char *aProfile,
+                                   int32_t argc, char **argv,
+                                   const char* aDesktopStartupID,
+                                   char **aResponse, bool *aSucceeded) = 0;
+};
+
+#endif // nsRemoteClient_h__