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
print(const char * s)29 static int print(const char *s)
30 {
31 return write(STDOUT_FILENO, s, __builtin_strlen(s));
32 }
33
num_to_str(unsigned long num,char * buf,int len)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
print_num(unsigned long num)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
print_k_value(const char * s,unsigned long num,unsigned long units)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 */
_start(void)73 void _start(void)
74 {
75 int ccode;
76 struct sysinfo info;
77 unsigned long used;
78 static const char *test_name = " get runtime memory use\n";
79
80 print("TAP version 13\n");
81 print("# Testing system size.\n");
82
83 ccode = sysinfo(&info);
84 if (ccode < 0) {
85 print("not ok 1");
86 print(test_name);
87 print(" ---\n reason: \"could not get sysinfo\"\n ...\n");
88 _exit(ccode);
89 }
90 print("ok 1");
91 print(test_name);
92
93 /* ignore cache complexities for now */
94 used = info.totalram - info.freeram - info.bufferram;
95 print("# System runtime memory report (units in Kilobytes):\n");
96 print(" ---\n");
97 print_k_value(" Total: ", info.totalram, info.mem_unit);
98 print_k_value(" Free: ", info.freeram, info.mem_unit);
99 print_k_value(" Buffer: ", info.bufferram, info.mem_unit);
100 print_k_value(" In use: ", used, info.mem_unit);
101 print(" ...\n");
102 print("1..1\n");
103
104 _exit(0);
105 }
106