remove usage of /dev/random in case openshit has a problem with this

remove usage of /dev/random in case openshit has a problem with this

openair1/SIMULATION/TOOLS/random_channel.c

@@ -530,12 +530,9 @@ channel_desc_t *new_channel_desc_scm(uint8_t nb_tx,
                                      float noise_power_dB) {
 
   // To create tables for normal distribution
-  uint64_t rand;
-  FILE *h = fopen("/dev/random", "r");
-  if (fread(&rand, sizeof(rand), 1, h) != 1) {
-    LOG_W(HW, "Simulator can't read /dev/random\n");
-  }
-  tableNor(rand);
+  struct timespec t;
+  clock_gettime(CLOCK_MONOTONIC, &t);
+  tableNor((long)(t.tv_nsec%INT_MAX));
 
   channel_desc_t *chan_desc = (channel_desc_t *)calloc(1,sizeof(channel_desc_t));
 

openair1/SIMULATION/TOOLS/rangen_double.c

@@ -110,6 +110,7 @@ double __attribute__ ((no_sanitize_address)) gaussdouble(double mean, double var
 }
 
 // Ziggurat
+static bool tableNordDone=false;
 static double wn[128], fn[128];
 static uint32_t iz, jz, jsr = 123456789, kn[128];
 static int32_t hz;
@@ -171,12 +172,18 @@ void tableNor(unsigned long seed)
     fn[i] = (exp(-0.5 * dn * dn));
     wn[i] = (dn / m1);
   }
-
+  tableNordDone=true;
   return;
 }
 
 double __attribute__ ((no_sanitize_address)) gaussZiggurat(double mean, double variance)
 {
+  if (!tableNordDone) {
+    // let's make reasonnable constant tables
+    struct timespec t;
+    clock_gettime(CLOCK_MONOTONIC, &t);
+    tableNor((long)(t.tv_nsec%INT_MAX));
+  }
   hz = SHR3;
   iz = hz & 127;
   return abs(hz) < kn[iz] ? hz * wn[iz] : nfix();