1/*
2 * Copyright (C) 2014 The Android Open Source Project
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 *  * Redistributions of source code must retain the above copyright
9 *    notice, this list of conditions and the following disclaimer.
10 *  * Redistributions in binary form must reproduce the above copyright
11 *    notice, this list of conditions and the following disclaimer in
12 *    the documentation and/or other materials provided with the
13 *    distribution.
14 *
15 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
16 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
17 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
18 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
19 * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
20 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
21 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
22 * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
23 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
24 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
25 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26 * SUCH DAMAGE.
27 */
28
29#include <sys/sysinfo.h>
30
31#include <dirent.h>
32#include <stdio.h>
33#include <string.h>
34#include <unistd.h>
35
36#include "private/get_cpu_count_from_string.h"
37#include "private/ScopedReaddir.h"
38
39static bool __matches_cpuN(const char* s) {
40  // The %c trick is to ensure that we have the anchored match "^cpu[0-9]+$".
41  unsigned cpu;
42  char dummy;
43  return (sscanf(s, "cpu%u%c", &cpu, &dummy) == 1);
44}
45
46int get_nprocs_conf() {
47  // On x86 kernels you can use /proc/cpuinfo for this, but on ARM kernels offline CPUs disappear
48  // from there. This method works on both.
49  ScopedReaddir reader("/sys/devices/system/cpu");
50  if (reader.IsBad()) {
51    return 1;
52  }
53
54  int result = 0;
55  dirent* entry;
56  while ((entry = reader.ReadEntry()) != NULL) {
57    if (entry->d_type == DT_DIR && __matches_cpuN(entry->d_name)) {
58      ++result;
59    }
60  }
61  return result;
62}
63
64int get_nprocs() {
65  int cpu_count = 1;
66  FILE* fp = fopen("/sys/devices/system/cpu/online", "re");
67  if (fp != nullptr) {
68    char* line = nullptr;
69    size_t len = 0;
70    if (getline(&line, &len, fp) != -1) {
71      cpu_count = GetCpuCountFromString(line);
72      free(line);
73    }
74    fclose(fp);
75  }
76  return cpu_count;
77}
78
79static int __get_meminfo_page_count(const char* pattern) {
80  FILE* fp = fopen("/proc/meminfo", "re");
81  if (fp == NULL) {
82    return -1;
83  }
84
85  int page_count = -1;
86  char buf[256];
87  while (fgets(buf, sizeof(buf), fp) != NULL) {
88    long total;
89    if (sscanf(buf, pattern, &total) == 1) {
90      page_count = static_cast<int>(total / (sysconf(_SC_PAGE_SIZE) / 1024));
91      break;
92    }
93  }
94  fclose(fp);
95  return page_count;
96}
97
98long get_phys_pages() {
99  return __get_meminfo_page_count("MemTotal: %ld kB");
100}
101
102long get_avphys_pages() {
103  return __get_meminfo_page_count("MemFree: %ld kB");
104}
105