release/src-rt-6.x.4708/linux/linux-2.6.36/testrootfs/init.c

   1 /*
   2  * Simple user-land program instead of real "init"
   3  */
   4 #include <stdlib.h>
   5 #include <unistd.h>
   6 #include <stdio.h>
   7 #include <errno.h>
   8 #include <string.h>
   9 #include <asm/ioctls.h>
  10 #include <sys/wait.h>
  11
  12 #include <linux/reboot.h>
  13
  14
  15 static volatile unsigned long long counter ;
  16
  17 void
  18 main_test_speed(unsigned sec, unsigned n)
  19 {
  20         int pfd[2];
  21         unsigned long start ;
  22         unsigned i;
  23
  24         printf("Testing speed with %d threads\n", n );
  25         start = time(NULL);
  26         counter = 0;
  27         pipe( pfd );
  28
  29         for(i = 0; i < n; i ++ )
  30                 {
  31                 int pid ;
  32                 if( (pid = fork()) != 0 )
  33                         continue;
  34                 /* Child process */
  35                 close(pfd[0]);
  36                 while( time(NULL) < (start + sec ) )
  37                         counter ++ ;
  38                 printf("Counter %llu\n", counter );
  39                 write( pfd[1], (void *) &counter, sizeof(counter) );
  40                 exit(0);
  41                 }
  42         /* Children running, parent waits */
  43         close(pfd[1]);
  44         while( time(NULL) < (start + sec ) )
  45                 sleep(1);
  46
  47         /* Retreive child exist status */
  48         for(counter = i = 0; i < n; i ++ )
  49                 {
  50                 unsigned long long cnt ;
  51                 int res;
  52                 if( read(pfd[0], &cnt, sizeof(cnt)) == sizeof(cnt))
  53                         counter += cnt ;
  54                 wait( &res );
  55                 printf("child %d status %d\n", i, WEXITSTATUS(res));
  56                 }
  57         printf("Average count %llu, or %d per sec \n",
  58                 counter / n, (int) (counter / n / sec) );
  59 }
  60
  61
  62 int
  63 main(int argc, char ** argv )
  64 {
  65         unsigned i, j;
  66         const unsigned seconds = 60;
  67         const unsigned dt = 5;
  68         char buf[128];
  69
  70         printf("Howdy from user-land! ! ! !\n");
  71
  72         for(j = i = 0; i < seconds; i += dt )
  73                 {
  74                 sleep(dt);
  75                 printf("Time is %d sec\n", time(NULL) );
  76                 ioctl(0, FIONREAD, &j);
  77                 if(j > 0 )
  78                         {
  79                         memset(buf, 0, sizeof(buf));
  80                         j = read(0, buf, sizeof(buf));
  81                         printf("Received %d characters from input:\n", j);
  82                         printf("'%s'\n", buf );
  83                         }
  84                 }
  85
  86 sleep(2);
  87 main_test_speed( 30, 1 );
  88 sleep(2);
  89 main_test_speed( 30, 2 );
  90 sleep(2);
  91 main_test_speed( 30, 3 );
  92 sleep(2);
  93 main_test_speed( 30, 4 );
  94
  95                 ioctl(0, FIONREAD, &j);
  96                 if(j > 0 )
  97                         {
  98                         memset(buf, 0, sizeof(buf));
  99                         j = read(0, buf, sizeof(buf));
 100                         printf("Received %d characters from input:\n", j);
 101                         printf("'%s'\n", buf );
 102                         }
 103 sleep(1);
 104 printf("Done couning, commiting suicide...\n");
 105 sleep(3);
 106 reboot( LINUX_REBOOT_CMD_RESTART );
 107 sleep(5);
 108 printf("reboot failed: %s\n", strerror(errno) );
 109 }