diff options
Diffstat (limited to 'variables.c')
| -rw-r--r-- | variables.c | 30 |
1 files changed, 28 insertions, 2 deletions
diff --git a/variables.c b/variables.c index 7aac2b71..11f074da 100644 --- a/variables.c +++ b/variables.c @@ -185,6 +185,7 @@ static SHELL_VAR *init_seconds_var __P((void)); static int brand __P((void)); static void sbrand __P((unsigned long)); /* set bash random number generator. */ +static void seedrand __P((void)); /* seed generator randomly */ static SHELL_VAR *assign_random __P((SHELL_VAR *, char *, arrayind_t)); static SHELL_VAR *get_random __P((SHELL_VAR *)); @@ -499,7 +500,7 @@ initialize_shell_variables (env, privmode) #endif /* HISTORY */ /* Seed the random number generator. */ - sbrand (dollar_dollar_pid + shell_start_time); + seedrand (); /* Handle some "special" variables that we may have inherited from a parent shell. */ @@ -1165,8 +1166,24 @@ static int seeded_subshell = 0; static int brand () { +#if 0 rseed = rseed * 1103515245 + 12345; return ((unsigned int)((rseed >> 16) & 32767)); /* was % 32768 */ +#else + /* From "Random number generators: good ones are hard to find", + Park and Miller, Communications of the ACM, vol. 31, no. 10, + October 1988, p. 1195. filtered through FreeBSD */ + long h, l; + + if (rseed == 0) + seedrand (); + h = rseed / 127773; + l = rseed % 127773; + rseed = 16807 * l - 2836 * h; + if (rseed < 0) + rseed += 0x7fffffff; + return ((unsigned int)(rseed & 32767)); /* was % 32768 */ +#endif } /* Set the random number generator seed to SEED. */ @@ -1178,6 +1195,15 @@ sbrand (seed) last_random_value = 0; } +static void +seedrand () +{ + struct timeval tv; + + gettimeofday (&tv, NULL); + sbrand (tv.tv_sec ^ tv.tv_usec ^ getpid ()); +} + static SHELL_VAR * assign_random (self, value, unused) SHELL_VAR *self; @@ -1199,7 +1225,7 @@ get_random_number () pid = getpid (); if (subshell_environment && seeded_subshell != pid) { - sbrand (rseed + pid + NOW); + seedrand (); seeded_subshell = pid; } |