Line data    Source code

       1             : #include <unistd.h>
       2             : 
       3             : #include "memory-util.h"
       4             : 
       5       93704 : size_t page_size(void) {
       6             :         static thread_local size_t pgsz = 0;
       7             :         long r;
       8             : 
       9       93704 :         if (_likely_(pgsz > 0))
      10       93528 :                 return pgsz;
      11             : 
      12         176 :         r = sysconf(_SC_PAGESIZE);
      13         176 :         assert(r > 0);
      14             : 
      15         176 :         pgsz = (size_t) r;
      16         176 :         return pgsz;
      17             : }
      18             : 
      19           4 : bool memeqzero(const void *data, size_t length) {
      20             :         /* Does the buffer consist entirely of NULs?
      21             :          * Copied from https://github.com/systemd/casync/, copied in turn from
      22             :          * https://github.com/rustyrussell/ccan/blob/master/ccan/mem/mem.c#L92,
      23             :          * which is licensed CC-0.
      24             :          */
      25             : 
      26           4 :         const uint8_t *p = data;
      27             :         size_t i;
      28             : 
      29             :         /* Check first 16 bytes manually */
      30          36 :         for (i = 0; i < 16; i++, length--) {
      31          35 :                 if (length == 0)
      32           1 :                         return true;
      33          34 :                 if (p[i])
      34           2 :                         return false;
      35             :         }
      36             : 
      37             :         /* Now we know first 16 bytes are NUL, memcmp with self.  */
      38           1 :         return memcmp(data, p + i, length) == 0;
      39             : }
      40             : 
      41             : #if !HAVE_EXPLICIT_BZERO
      42             : /*
      43             :  * The pointer to memset() is volatile so that compiler must de-reference the pointer and can't assume that
      44             :  * it points to any function in particular (such as memset(), which it then might further "optimize"). This
      45             :  * approach is inspired by openssl's crypto/mem_clr.c.
      46             :  */
      47             : typedef void *(*memset_t)(void *,int,size_t);
      48             : 
      49             : static volatile memset_t memset_func = memset;
      50             : 
      51             : void* explicit_bzero_safe(void *p, size_t l) {
      52             :         if (l > 0)
      53             :                 memset_func(p, '\0', l);
      54             : 
      55             :         return p;
      56             : }
      57             : #endif