src/cpuset_parse.c

   1 /* SPDX-License-Identifier: LGPL-2.1+ */
   2
   3 #include "config.h"
   4
   5 #include <stdio.h>
   6 #include <string.h>
   7 #include <stdbool.h>
   8 #include <stdlib.h>
   9
  10 #include "cgroups/cgroup.h"
  11 #include "cgroups/cgroup_utils.h"
  12 #include "memory_utils.h"
  13
  14 /*
  15  * Helper functions for cpuset_in-set
  16  */
  17 static char *cpuset_nexttok(const char *c)
  18 {
  19         char *r;
  20
  21         if (!strlen(c))
  22                 return NULL;
  23
  24         r = strchr(c + 1, ',');
  25         return r ? (r + 1) : NULL;
  26 }
  27
  28 static int cpuset_getrange(const char *c, int *a, int *b)
  29 {
  30         int ret;
  31
  32         ret = sscanf(c, "%d-%d", a, b);
  33         return ret;
  34 }
  35
  36 /*
  37  * cpusets are in format "1,2-3,4"
  38  * iow, comma-delimited ranges
  39  */
  40 bool cpu_in_cpuset(int cpu, const char *cpuset)
  41 {
  42         for (const char *c = cpuset; c; c = cpuset_nexttok(c)) {
  43                 int a, b, ret;
  44
  45                 ret = cpuset_getrange(c, &a, &b);
  46                 if (ret == 1 && cpu == a) /* "1" or "1,6" */
  47                         return true;
  48                 else if (ret == 2 && cpu >= a && cpu <= b) /* range match */
  49                         return true;
  50         }
  51
  52         return false;
  53 }
  54
  55 /*
  56  * get cpu number in cpuset
  57  */
  58 int cpu_number_in_cpuset(const char *cpuset)
  59 {
  60         int cpu_number = 0;
  61
  62         for (const char *c = cpuset; c; c = cpuset_nexttok(c)) {
  63                 int a, b, ret;
  64
  65                 ret = cpuset_getrange(c, &a, &b);
  66                 if (ret == 1)
  67                         cpu_number++;
  68                 else if (ret == 2)
  69                         cpu_number += a > b ? a - b + 1 : b - a + 1;
  70         }
  71
  72         return cpu_number;
  73 }