FileMap::create: remove duplicate addition.android-security-8.0.0_r54android-security-8.0.0_r53android-security-8.0.0_r52oreo-security-release

The previous change was intended to detect the overflow, but
accidentally retained the existing addition, so we'd abort before
getting to the explicit check.

Also reformat slightly to better match the current code in qt-dev and
beyond, to reduce merge conflicts.

Bug: 156997193
Test: treehugger
Change-Id: I73a3a4e75f0aad00888e8f2b49a07b7e8b4eda05
Merged-In: I73a3a4e75f0aad00888e8f2b49a07b7e8b4eda05
(cherry picked from commit 54794ac613d50bf4072174476f60527e2b0b4cdf)

1 files changed, 7 insertions, 14 deletions

diff --git a/libutils/FileMap.cpp b/libutils/FileMap.cpp
index b9f411ef2..45ca85392 100644
--- a/libutils/FileMap.cpp
+++ b/libutils/FileMap.cpp
@@ -160,12 +160,6 @@ bool FileMap::create(const char* origFileName, int fd, off64_t offset, size_t le
         return false;
     }
 #else // !defined(__MINGW32__)
-    int     prot, flags, adjust;
-    off64_t adjOffset;
-    size_t  adjLength;
-
-    void* ptr;
-
     assert(fd >= 0);
     assert(offset >= 0);
     assert(length > 0);
@@ -179,20 +173,19 @@ bool FileMap::create(const char* origFileName, int fd, off64_t offset, size_t le
         }
     }
 
-    adjust = offset % mPageSize;
-    adjOffset = offset - adjust;
-    adjLength = length + adjust;
+    int adjust = offset % mPageSize;
+    off64_t adjOffset = offset - adjust;
+    size_t adjLength;
     if (__builtin_add_overflow(length, adjust, &adjLength)) {
         ALOGE("adjusted length overflow: length %zu adjust %d", length, adjust);
         return false;
     }
 
-    flags = MAP_SHARED;
-    prot = PROT_READ;
-    if (!readOnly)
-        prot |= PROT_WRITE;
+    int flags = MAP_SHARED;
+    int prot = PROT_READ;
+    if (!readOnly) prot |= PROT_WRITE;
 
-    ptr = mmap(NULL, adjLength, prot, flags, fd, adjOffset);
+    void* ptr = mmap(nullptr, adjLength, prot, flags, fd, adjOffset);
     if (ptr == MAP_FAILED) {
         ALOGE("mmap(%lld,%zu) failed: %s\n",
             (long long)adjOffset, adjLength, strerror(errno));