make-random-seed-more-random-1.patch

diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index eedc617..2d5a0ac 100644
*** a/src/backend/postmaster/postmaster.c
--- b/src/backend/postmaster/postmaster.c
*************** ClosePostmasterPorts(bool am_syslogger)
*** 2520,2530 ****
  /*
   * InitProcessGlobals -- set MyProcPid, MyStartTime[stamp], random seeds
   *
!  * Called early in every backend.
   */
  void
  InitProcessGlobals(void)
  {
  	MyProcPid = getpid();
  	MyStartTimestamp = GetCurrentTimestamp();
  	MyStartTime = timestamptz_to_time_t(MyStartTimestamp);
--- 2520,2532 ----
  /*
   * InitProcessGlobals -- set MyProcPid, MyStartTime[stamp], random seeds
   *
!  * Called early in the postmaster and every backend.
   */
  void
  InitProcessGlobals(void)
  {
+ 	unsigned int rseed;
+ 
  	MyProcPid = getpid();
  	MyStartTimestamp = GetCurrentTimestamp();
  	MyStartTime = timestamptz_to_time_t(MyStartTimestamp);
*************** InitProcessGlobals(void)
*** 2539,2553 ****
  #endif
  
  	/*
! 	 * Set a different seed for random() in every backend.  Since PIDs and
! 	 * timestamps tend to change more frequently in their least significant
! 	 * bits, shift the timestamp left to allow a larger total number of seeds
! 	 * in a given time period.  Since that would leave only 20 bits of the
! 	 * timestamp that cycle every ~1 second, also mix in some higher bits.
  	 */
! 	srandom(((uint64) MyProcPid) ^
  			((uint64) MyStartTimestamp << 12) ^
! 			((uint64) MyStartTimestamp >> 20));
  }
  
  
--- 2541,2570 ----
  #endif
  
  	/*
! 	 * Set a different seed for random() in every process.  We want something
! 	 * unpredictable, so if possible, use high-quality random bits for the
! 	 * seed.  Otherwise, fall back to a seed based on timestamp and PID.
! 	 *
! 	 * Note we can't use pg_backend_random here, since this is used in the
! 	 * postmaster, and even in a backend we might not be attached to shared
! 	 * memory yet.
  	 */
! #ifdef HAVE_STRONG_RANDOM
! 	if (!pg_strong_random(&rseed, sizeof(rseed)))
! #endif
! 	{
! 		/*
! 		 * Since PIDs and timestamps tend to change more frequently in their
! 		 * least significant bits, shift the timestamp left to allow a larger
! 		 * total number of seeds in a given time period.  Since that would
! 		 * leave only 20 bits of the timestamp that cycle every ~1 second,
! 		 * also mix in some higher bits.
! 		 */
! 		rseed = ((uint64) MyProcPid) ^
  			((uint64) MyStartTimestamp << 12) ^
! 			((uint64) MyStartTimestamp >> 20);
! 	}
! 	srandom(rseed);
  }