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      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 
     39 static 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 
     46 int 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 
     64 int 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 
     79 static 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 
     98 long get_phys_pages() {
     99   return __get_meminfo_page_count("MemTotal: %ld kB");
    100 }
    101 
    102 long get_avphys_pages() {
    103   return __get_meminfo_page_count("MemFree: %ld kB");
    104 }
    105