third_party/sqlite/patches/0012-Allow-read-only-memory-mapping.patch

   1 From 0b346776e7a4d775932a18970801fa48d7a5ce11 Mon Sep 17 00:00:00 2001
   2 From: Scott Hess <shess@chromium.org>
   3 Date: Wed, 5 Aug 2015 16:44:32 -0700
   4 Subject: [PATCH 12/12] Allow read-only memory mapping.
   5
   6 In memory-mapped I/O mode, SQLite writes pages by using memcpy() from
   7 the staging memory into the underlying memory-mapped file.  This allows
   8 anyone in the process to also write into that space.  Modify SQLite to
   9 map things read-only.
  10
  11 TODO: Upstream.
  12
  13 BUG=489784
  14 ---
  15  third_party/sqlite/src/src/os_unix.c | 4 ++++
  16  third_party/sqlite/src/src/os_win.c  | 4 ++++
  17  2 files changed, 8 insertions(+)
  18
  19 diff --git a/third_party/sqlite/src/src/os_unix.c b/third_party/sqlite/src/src/os_unix.c
  20 index 75b71dc..eaa97cf 100644
  21 --- a/third_party/sqlite/src/src/os_unix.c
  22 +++ b/third_party/sqlite/src/src/os_unix.c
  23 @@ -3341,6 +3341,7 @@ static int unixWrite(
  24    }
  25  #endif
  26
  27 +#if !SQLITE_MMAP_READ_ONLY
  28  #if SQLITE_MAX_MMAP_SIZE>0
  29    /* Deal with as much of this write request as possible by transfering
  30    ** data from the memory mapping using memcpy().  */
  31 @@ -3357,6 +3358,7 @@ static int unixWrite(
  32      }
  33    }
  34  #endif
  35 +#endif
  36
  37    while( amt>0 && (wrote = seekAndWrite(pFile, offset, pBuf, amt))>0 ){
  38      amt -= wrote;
  39 @@ -4743,7 +4745,9 @@ static void unixRemapfile(
  40    assert( pFd->mmapSizeActual>=pFd->mmapSize );
  41    assert( MAP_FAILED!=0 );
  42
  43 +#if !SQLITE_MMAP_READ_ONLY
  44    if( (pFd->ctrlFlags & UNIXFILE_RDONLY)==0 ) flags |= PROT_WRITE;
  45 +#endif
  46
  47    if( pOrig ){
  48  #if HAVE_MREMAP
  49 diff --git a/third_party/sqlite/src/src/os_win.c b/third_party/sqlite/src/src/os_win.c
  50 index 9320bfc..2e757f8 100644
  51 --- a/third_party/sqlite/src/src/os_win.c
  52 +++ b/third_party/sqlite/src/src/os_win.c
  53 @@ -2558,6 +2558,7 @@ static int winWrite(
  54    OSTRACE(("WRITE file=%p, buffer=%p, amount=%d, offset=%lld, lock=%d\n",
  55             pFile->h, pBuf, amt, offset, pFile->locktype));
  56
  57 +#if !SQLITE_MMAP_READ_ONLY
  58  #if SQLITE_MAX_MMAP_SIZE>0
  59    /* Deal with as much of this write request as possible by transfering
  60    ** data from the memory mapping using memcpy().  */
  61 @@ -2575,6 +2576,7 @@ static int winWrite(
  62      }
  63    }
  64  #endif
  65 +#endif
  66
  67  #if SQLITE_OS_WINCE
  68    rc = winSeekFile(pFile, offset);
  69 @@ -4021,10 +4023,12 @@ static int winMapfile(winFile *pFd, sqlite3_int64 nByte){
  70      DWORD flags = FILE_MAP_READ;
  71
  72      winUnmapfile(pFd);
  73 +#if !SQLITE_MMAP_READ_ONLY
  74      if( (pFd->ctrlFlags & WINFILE_RDONLY)==0 ){
  75        protect = PAGE_READWRITE;
  76        flags |= FILE_MAP_WRITE;
  77      }
  78 +#endif
  79  #if SQLITE_OS_WINRT
  80      pFd->hMap = osCreateFileMappingFromApp(pFd->h, NULL, protect, nMap, NULL);
  81  #elif defined(SQLITE_WIN32_HAS_WIDE)
  82 --
  83 2.4.5
  84