[tor-commits] [tor-browser/tor-browser-60.1.0esr-8.0-1] Revert "Bug 20283: Tor Browser should run without a `/proc` filesystem."

[gk at torproject.org]

commit 2edb3478a22331e0fc882e25874b9403ee2575ee
Author: Georg Koppen <gk at torproject.org>
Date:   Wed Jul 4 16:51:23 2018 +0000

    Revert "Bug 20283: Tor Browser should run without a `/proc` filesystem."
    
    This reverts commit 5bd6e492edc3fc4df748d1228360c80fee38e276.
---
 js/src/util/NativeStack.cpp | 60 +++------------------------------------------
 1 file changed, 4 insertions(+), 56 deletions(-)

diff --git a/js/src/util/NativeStack.cpp b/js/src/util/NativeStack.cpp
index a695cb3bcd6c..2507374a36da 100644
--- a/js/src/util/NativeStack.cpp
+++ b/js/src/util/NativeStack.cpp
@@ -13,24 +13,10 @@
 # if defined(__FreeBSD__) || defined(__OpenBSD__) || defined(__DragonFly__)
 #  include <pthread_np.h>
 # endif
-# if defined(SOLARIS) || defined(AIX)
-#  include <ucontext.h>
-# endif
 # if defined(ANDROID) && !defined(__aarch64__)
 #  include <sys/types.h>
 #  include <unistd.h>
 # endif
-# if defined(XP_LINUX) && !defined(ANDROID) && defined(__GLIBC__)
-#  include <dlfcn.h>
-#  include <sys/syscall.h>
-#  include <sys/types.h>
-#  include <unistd.h>
-static pid_t
-gettid()
-{
-    return syscall(__NR_gettid);
-}
-# endif
 #else
 # error "Unsupported platform"
 #endif
@@ -48,6 +34,8 @@ js::GetNativeStackBaseImpl()
 
 #elif defined(SOLARIS)
 
+#include <ucontext.h>
+
 JS_STATIC_ASSERT(JS_STACK_GROWTH_DIRECTION < 0);
 
 void*
@@ -60,6 +48,8 @@ js::GetNativeStackBaseImpl()
 
 #elif defined(AIX)
 
+#include <ucontext.h>
+
 JS_STATIC_ASSERT(JS_STACK_GROWTH_DIRECTION < 0);
 
 void*
@@ -71,48 +61,6 @@ js::GetNativeStackBaseImpl()
         context.uc_stack.ss_size;
 }
 
-#elif defined(XP_LINUX) && !defined(ANDROID) && defined(__GLIBC__)
-void*
-js::GetNativeStackBaseImpl()
-{
-    // On the main thread, get stack base from glibc's __libc_stack_end rather than pthread APIs
-    // to avoid filesystem calls /proc/self/maps.  Non-main threads spawned with pthreads can read
-    // this information directly from their pthread struct, but the main thread must go parse
-    // /proc/self/maps to figure the mapped stack address space ranges.  We want to avoid reading
-    // from /proc/ so that firefox can run in sandboxed environments where /proc may not be mounted
-    if (gettid() == getpid()) {
-        void** pLibcStackEnd = (void**)dlsym(RTLD_DEFAULT, "__libc_stack_end");
-        // If __libc_stack_end is not found, architecture specific frame pointer hopping will need
-        // to be implemented.
-        MOZ_RELEASE_ASSERT(pLibcStackEnd, "__libc_stack_end unavailable, unable to setup stack range for JS");
-        void* stackBase = *pLibcStackEnd;
-        MOZ_RELEASE_ASSERT(stackBase, "invalid stack base, unable to setup stack range for JS");
-        // We don't need to fix stackBase, as it already roughly points to beginning of the stack
-        return stackBase;
-    } else {
-    // Non-main threads have the required info stored in memory, so no filesystem calls are made.
-        pthread_t thread = pthread_self();
-        pthread_attr_t sattr;
-        pthread_attr_init(&sattr);
-        pthread_getattr_np(thread, &sattr);
-        // stackBase will be the *lowest* address on all architectures.
-        void* stackBase = nullptr;
-        size_t stackSize = 0;
-        int rc = pthread_attr_getstack(&sattr, &stackBase, &stackSize);
-        if (rc) {
-            MOZ_CRASH("call to pthread_attr_getstack failed, unable to setup stack range for JS");
-        }
-        MOZ_RELEASE_ASSERT(stackBase, "invalid stack base, unable to setup stack range for JS");
-        pthread_attr_destroy(&sattr);
-
-# if JS_STACK_GROWTH_DIRECTION > 0
-        return stackBase;
-# else
-        return static_cast<char*>(stackBase) + stackSize;
-# endif
-    }
-}
-
 #else /* XP_UNIX */
 
 void*