Set errno in various failure cases. Do not attempt to zero nullptr.

microsoft · Feb 22, 2022 · 6f6f4df · 6f6f4df
1 parent 6a71b84
commit 6f6f4df
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Showing 4 changed files with 15 additions and 4 deletions.
diff --git a/src/mem/chunkallocator.h b/src/mem/chunkallocator.h
@@ -194,6 +194,7 @@ namespace snmalloc
       if (slab_sizeclass >= NUM_SLAB_SIZES)
       {
         // Your address space is not big enough for this allocation!
+        errno = ENOMEM;
         return {nullptr, nullptr};
       }
 

diff --git a/src/mem/external_alloc.h b/src/mem/external_alloc.h
@@ -56,15 +56,20 @@ namespace snmalloc::external_alloc
     if constexpr (bits::BITS == 64)
     {
       if (size >= 0x10000000000)
+      {
+        errno = ENOMEM;
         return nullptr;
+      }
     }
 
     if (alignment < sizeof(void*))
       alignment = sizeof(void*);
 
     void* result;
-    if (posix_memalign(&result, alignment, size) != 0)
+    int err = posix_memalign(&result, alignment, size);
+    if (err != 0)
     {
+      errno = err;
       result = nullptr;
     }
     return result;

diff --git a/src/mem/localalloc.h b/src/mem/localalloc.h
@@ -198,7 +198,7 @@ namespace snmalloc
         if (meta != nullptr)
           meta->initialise_large();
 
-        if (zero_mem == YesZero)
+        if (zero_mem == YesZero && chunk.unsafe_ptr() != nullptr)
         {
           SharedStateHandle::Pal::template zero<false>(
             chunk.unsafe_ptr(), size);
@@ -427,7 +427,7 @@ namespace snmalloc
       // would guarantee.
       void* result = external_alloc::aligned_alloc(
         natural_alignment(size), round_size(size));
-      if constexpr (zero_mem == YesZero)
+      if (zero_mem == YesZero && result != nullptr)
         memset(result, 0, size);
       return result;
 #else

diff --git a/src/pal/pal_windows.h b/src/pal/pal_windows.h
@@ -186,13 +186,18 @@ namespace snmalloc
 
       void* ret = VirtualAlloc2FromApp(
         nullptr, nullptr, size, flags, PAGE_READWRITE, &param, 1);
+      if (ret == nullptr)
+        errno = ENOMEM;
       return ret;
     }
 #  endif
 
     static void* reserve(size_t size) noexcept
     {
-      return VirtualAlloc(nullptr, size, MEM_RESERVE, PAGE_READWRITE);
+      void* ret = VirtualAlloc(nullptr, size, MEM_RESERVE, PAGE_READWRITE);
+      if (ret == nullptr)
+        errno = ENOMEM;
+      return ret;
     }
 
     /**