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authorAdhemerval Zanella <adhemerval.zanella@linaro.org>2015-08-27 16:44:04 -0300
committerAdhemerval Zanella <adhemerval.zanella@linaro.com>2015-08-28 10:42:07 -0300
commitd3573f61aca67a398de7eaa7593d3973cb5fd154 (patch)
treeae2d3f6feeb9c8109da990bbd9c93dcb0291e769 /sysdeps
parent8c17cb1f6455c7a5fd6a1d05a2394129dbce012b (diff)
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Fix wordsize-32 mmap offset for negative value (BZ#18877)
This patch fixes the default wordsize-32 mmap implementation offset
calculation for negative values.  Current code uses signed shift
operation to calculate the multiple size to use with syscall and
it is implementation defined.  Change it to use a division base
on mmap page size (default being as before, 4096).

Tested on armv7hf.

	[BZ #18877]
	* posix/Makefile (tests): Add tst-mmap-offset.
	* posix/tst-mmap.c: New file.
	* sysdeps/unix/sysv/linux/generic/wordsize-32/mmap.c (__mmap): Fix
	offset calculation for negative values.
Diffstat (limited to 'sysdeps')
-rw-r--r--sysdeps/unix/sysv/linux/generic/wordsize-32/mmap.c8
1 files changed, 4 insertions, 4 deletions
diff --git a/sysdeps/unix/sysv/linux/generic/wordsize-32/mmap.c b/sysdeps/unix/sysv/linux/generic/wordsize-32/mmap.c
index 24835ce9cc..75790f1996 100644
--- a/sysdeps/unix/sysv/linux/generic/wordsize-32/mmap.c
+++ b/sysdeps/unix/sysv/linux/generic/wordsize-32/mmap.c
@@ -21,20 +21,20 @@
 #include <errno.h>
 #include <sysdep.h>
 
-#ifndef MMAP_PAGE_SHIFT
-#define MMAP_PAGE_SHIFT 12
+#ifndef MMAP_PAGE_UNIT
+# define MMAP_PAGE_UNIT 4096UL
 #endif
 
 __ptr_t
 __mmap (__ptr_t addr, size_t len, int prot, int flags, int fd, off_t offset)
 {
-  if (offset & ((1 << MMAP_PAGE_SHIFT) - 1))
+  if (offset & (MMAP_PAGE_UNIT - 1))
     {
       __set_errno (EINVAL);
       return MAP_FAILED;
     }
   return (__ptr_t) INLINE_SYSCALL (mmap2, 6, addr, len, prot, flags, fd,
-                                   offset >> MMAP_PAGE_SHIFT);
+                                   offset / MMAP_PAGE_UNIT);
 }
 
 weak_alias (__mmap, mmap)