[PATCH] Use arc4random instead of rand where available
Jeremy Huddleston
jeremyhu at freedesktop.org
Mon Mar 22 12:16:13 PDT 2010
Mainly to shut up clang. These are not security-sensitive uses of rand()
Signed-off-by: Jeremy Huddleston <jeremyhu at apple.com>
---
configure.ac | 2 +-
dix/window.c | 18 ++++++++++++++++++
exa/exa_glyphs.c | 8 ++++++++
include/dix-config.h.in | 3 +++
4 files changed, 30 insertions(+), 1 deletions(-)
diff --git a/configure.ac b/configure.ac
index d379b3a..361f380 100644
--- a/configure.ac
+++ b/configure.ac
@@ -206,7 +206,7 @@ dnl Checks for library functions.
AC_FUNC_VPRINTF
AC_CHECK_FUNCS([geteuid getuid link memmove memset mkstemp strchr strrchr \
strtol getopt getopt_long vsnprintf walkcontext backtrace \
- getisax getzoneid shmctl64 strcasestr ffs])
+ getisax getzoneid shmctl64 strcasestr ffs arc4random])
AC_FUNC_ALLOCA
dnl Old HAS_* names used in os/*.c.
AC_CHECK_FUNC([getdtablesize],
diff --git a/dix/window.c b/dix/window.c
index c7201df..303cf4d 100644
--- a/dix/window.c
+++ b/dix/window.c
@@ -3189,10 +3189,17 @@ dixSaveScreens(ClientPtr client, int on, int mode)
if (logoScreenSaver)
(*pWin->drawable.pScreen->ClearToBackground)(pWin, 0, 0, 0, 0, FALSE);
#endif
+#ifdef HAVE_ARC4RANDOM
+ (*pWin->drawable.pScreen->MoveWindow)(pWin,
+ (short)(-(arc4random() % RANDOM_WIDTH)),
+ (short)(-(arc4random() % RANDOM_WIDTH)),
+ pWin->nextSib, VTMove);
+#else
(*pWin->drawable.pScreen->MoveWindow)(pWin,
(short)(-(rand() % RANDOM_WIDTH)),
(short)(-(rand() % RANDOM_WIDTH)),
pWin->nextSib, VTMove);
+#endif
#ifndef NOLOGOHACK
if (logoScreenSaver)
DrawLogo(pWin);
@@ -3732,7 +3739,11 @@ DrawLogo(WindowPtr pWin)
if (!pGC)
return;
+#ifdef HAVE_ARC4RANDOM
+ if ((arc4random() % 100) <= 17) /* make the probability for white fairly low */
+#else
if ((rand() % 100) <= 17) /* make the probability for white fairly low */
+#endif
fore[0].val = pScreen->whitePixel;
else
fore[0].val = pScreen->blackPixel;
@@ -3776,10 +3787,17 @@ DrawLogo(WindowPtr pWin)
size = width;
if (height < width)
size = height;
+#ifdef HAVE_ARC4RANDOM
+ size = RANDOM_WIDTH + arc4random() % (size - RANDOM_WIDTH);
+ size &= ~1;
+ x += arc4random() % (width - size);
+ y += arc4random() % (height - size);
+#else
size = RANDOM_WIDTH + rand() % (size - RANDOM_WIDTH);
size &= ~1;
x += rand() % (width - size);
y += rand() % (height - size);
+#endif
/*
* Draw what will be the thin strokes.
diff --git a/exa/exa_glyphs.c b/exa/exa_glyphs.c
index fd14e9b..8c9e591 100644
--- a/exa/exa_glyphs.c
+++ b/exa/exa_glyphs.c
@@ -223,7 +223,11 @@ exaRealizeGlyphCaches(ScreenPtr pScreen,
for (j = 0; j < cache->hashSize; j++)
cache->hashEntries[j] = -1;
+#ifdef HAVE_ARC4RANDOM
+ cache->evictionPosition = arc4random() % cache->size;
+#else
cache->evictionPosition = rand() % cache->size;
+#endif
}
/* Each cache references the picture individually */
@@ -504,7 +508,11 @@ exaGlyphCacheBufferGlyph(ScreenPtr pScreen,
exaGlyphCacheHashInsert(cache, pGlyph, pos);
/* And pick a new eviction position */
+#ifdef HAVE_ARC4RANDOM
+ cache->evictionPosition = arc4random() % cache->size;
+#else
cache->evictionPosition = rand() % cache->size;
+#endif
}
exaGlyphCacheUploadGlyph(pScreen, cache, x, y, pGlyph);
diff --git a/include/dix-config.h.in b/include/dix-config.h.in
index 058c8fd..2ded353 100644
--- a/include/dix-config.h.in
+++ b/include/dix-config.h.in
@@ -54,6 +54,9 @@
/* Support XDM-AUTH*-1 */
#undef HASXDMAUTH
+/* Define to 1 if you have the `arc4random' function. */
+#undef HAVE_ARC4RANDOM
+
/* Define to 1 if you have the `getdtablesize' function. */
#undef HAS_GETDTABLESIZE
--
1.6.2
-------------- next part --------------
A non-text attachment was scrubbed...
Name: smime.p7s
Type: application/pkcs7-signature
Size: 5820 bytes
Desc: not available
URL: <http://lists.x.org/archives/xorg-devel/attachments/20100322/403466b0/attachment-0001.bin>
More information about the xorg-devel
mailing list