Bug 1701182 - Prepend SNAP-specific prefix to shm path. r=stransky

Differential Revision: https://phabricator.services.mozilla.com/D110269

browser/components/shell/nsGNOMEShellService.cpp

@@ -23,6 +23,7 @@
 #include "imgIRequest.h"
 #include "imgIContainer.h"
 #include "mozilla/Sprintf.h"
+#include "mozilla/WidgetUtils.h"
 #include "mozilla/dom/Element.h"
 #if defined(MOZ_WIDGET_GTK)
 #  include "nsIImageToPixbuf.h"
@@ -72,17 +73,15 @@ static const MimeTypeAssociation appTypes[] = {
 #define kDesktopColorGSKey "primary-color"
 
 static bool IsRunningAsASnap() {
-  // SNAP holds the path to the snap, use SNAP_NAME
-  // which is easier to parse.
-  const char* snap_name = PR_GetEnv("SNAP_NAME");
+  const char* snapName = mozilla::widget::WidgetUtils::GetSnapInstanceName();
 
   // return early if not set.
-  if (snap_name == nullptr) {
+  if (snapName == nullptr) {
     return false;
   }
 
-  // snap_name as defined on https://snapcraft.io/firefox
-  return (strcmp(snap_name, "firefox") == 0);
+  // snapName as defined on https://snapcraft.io/firefox
+  return (strcmp(snapName, "firefox") == 0);
 }
 
 nsresult nsGNOMEShellService::Init() {

toolkit/profile/nsToolkitProfileService.cpp

@@ -6,6 +6,7 @@
 #include "mozilla/ArrayUtils.h"
 #include "mozilla/UniquePtr.h"
 #include "mozilla/UniquePtrExtensions.h"
+#include "mozilla/WidgetUtils.h"
 
 #include <stdio.h>
 #include <stdlib.h>
@@ -1833,14 +1834,15 @@ nsToolkitProfileService::CreateProfile(nsIFile* aRootDir,
  * get essentially the same benefits as dedicated profiles provides.
  */
 bool nsToolkitProfileService::IsSnapEnvironment() {
-  // Copied from IsRunningAsASnap() in
-  // browser/components/shell/nsGNOMEShellService.cpp
-  // TODO: factor out this common code in one place.
-  const char* snap_name = PR_GetEnv("SNAP_NAME");
-  if (snap_name == nullptr) {
+  const char* snapName = mozilla::widget::WidgetUtils::GetSnapInstanceName();
+
+  // return early if not set.
+  if (snapName == nullptr) {
     return false;
   }
-  return (strcmp(snap_name, "firefox") == 0);
+
+  // snapName as defined on https://snapcraft.io/firefox
+  return (strcmp(snapName, "firefox") == 0);
 }
 
 /**

widget/WidgetUtils.cpp

@@ -13,6 +13,7 @@
 #include "nsIBidiKeyboard.h"
 #include "nsIStringBundle.h"
 #include "nsTArray.h"
+#include "prenv.h"
 #ifdef XP_WIN
 #  include "WinUtils.h"
 #endif
@@ -145,5 +146,14 @@ void WidgetUtils::GetBrandShortName(nsAString& aBrandName) {
   }
 }
 
+const char* WidgetUtils::GetSnapInstanceName() {
+  char* instanceName = PR_GetEnv("SNAP_INSTANCE_NAME");
+  if (instanceName != nullptr) {
+    return instanceName;
+  }
+  // Compatibility for snapd <= 2.35:
+  return PR_GetEnv("SNAP_NAME");
+}
+
 }  // namespace widget
 }  // namespace mozilla

widget/WidgetUtils.h

@@ -93,6 +93,11 @@ class WidgetUtils {
    * Get branchShortName from string bundle
    */
   static void GetBrandShortName(nsAString& aBrandName);
+
+  /* When packaged as a snap, strict confinement needs to be accounted for.
+     See https://snapcraft.io/docs for details.
+     Return the snap's instance name, or null when not running as a snap. */
+  static const char* GetSnapInstanceName();
 };
 
 }  // namespace widget

widget/gtk/WindowSurfaceWayland.cpp

@@ -16,6 +16,7 @@
 #include "nsTArray.h"
 #include "mozilla/ScopeExit.h"
 #include "mozilla/StaticPrefs_widget.h"
+#include "mozilla/WidgetUtils.h"
 
 #include <sys/mman.h>
 #include <fcntl.h>
@@ -169,9 +170,17 @@ RefPtr<nsWaylandDisplay> WindowBackBuffer::GetWaylandDisplay() {
 
 static int WaylandAllocateShmMemory(int aSize) {
   int fd = -1;
+
+  nsCString shmPrefix("/");
+  const char* snapName = mozilla::widget::WidgetUtils::GetSnapInstanceName();
+  if (snapName != nullptr) {
+    shmPrefix.AppendPrintf("snap.%s.", snapName);
+  }
+  shmPrefix.Append("wayland.mozilla.ipc");
+
   do {
     static int counter = 0;
-    nsPrintfCString shmName("/wayland.mozilla.ipc.%d", counter++);
+    nsPrintfCString shmName("%s.%d", shmPrefix.get(), counter++);
     fd = shm_open(shmName.get(), O_CREAT | O_RDWR | O_EXCL, 0600);
     if (fd >= 0) {
       // We don't want to use leaked file