tools/testing/selftests/size/get_size.c

   1 /*
   2  * Copyright 2014 Sony Mobile Communications Inc.
   3  *
   4  * Licensed under the terms of the GNU GPL License version 2
   5  *
   6  * Selftest for runtime system size
   7  *
   8  * Prints the amount of RAM that the currently running system is using.
   9  *
  10  * This program tries to be as small as possible itself, to
  11  * avoid perturbing the system memory utilization with its
  12  * own execution.  It also attempts to have as few dependencies
  13  * on kernel features as possible.
  14  *
  15  * It should be statically linked, with startup libs avoided.
  16  * It uses no library calls, and only the following 3 syscalls:
  17  *   sysinfo(), write(), and _exit()
  18  *
  19  * For output, it avoids printf (which in some C libraries
  20  * has large external dependencies) by  implementing it's own
  21  * number output and print routines, and using __builtin_strlen()
  22  */
  23
  24 #include <sys/sysinfo.h>
  25 #include <unistd.h>
  26
  27 #define STDOUT_FILENO 1
  28
  29 static int print(const char *s)
  30 {
  31         return write(STDOUT_FILENO, s, __builtin_strlen(s));
  32 }
  33
  34 static inline char *num_to_str(unsigned long num, char *buf, int len)
  35 {
  36         unsigned int digit;
  37
  38         /* put digits in buffer from back to front */
  39         buf += len - 1;
  40         *buf = 0;
  41         do {
  42                 digit = num % 10;
  43                 *(--buf) = digit + '0';
  44                 num /= 10;
  45         } while (num > 0);
  46
  47         return buf;
  48 }
  49
  50 static int print_num(unsigned long num)
  51 {
  52         char num_buf[30];
  53
  54         return print(num_to_str(num, num_buf, sizeof(num_buf)));
  55 }
  56
  57 static int print_k_value(const char *s, unsigned long num, unsigned long units)
  58 {
  59         unsigned long long temp;
  60         int ccode;
  61
  62         print(s);
  63
  64         temp = num;
  65         temp = (temp * units)/1024;
  66         num = temp;
  67         ccode = print_num(num);
  68         print("\n");
  69         return ccode;
  70 }
  71
  72 /* this program has no main(), as startup libraries are not used */
  73 void _start(void)
  74 {
  75         int ccode;
  76         struct sysinfo info;
  77         unsigned long used;
  78
  79         print("Testing system size.\n");
  80         print("1..1\n");
  81
  82         ccode = sysinfo(&info);
  83         if (ccode < 0) {
  84                 print("not ok 1 get runtime memory use\n");
  85                 print("# could not get sysinfo\n");
  86                 _exit(ccode);
  87         }
  88         /* ignore cache complexities for now */
  89         used = info.totalram - info.freeram - info.bufferram;
  90         print_k_value("ok 1 get runtime memory use # size = ", used,
  91                 info.mem_unit);
  92
  93         print("# System runtime memory report (units in Kilobytes):\n");
  94         print_k_value("#   Total:  ", info.totalram, info.mem_unit);
  95         print_k_value("#   Free:   ", info.freeram, info.mem_unit);
  96         print_k_value("#   Buffer: ", info.bufferram, info.mem_unit);
  97         print_k_value("#   In use: ", used, info.mem_unit);
  98
  99         _exit(0);
 100 }