cgroup.c

   1 #include <limits.h>
   2 #include <stdio.h>
   3 #include <stdlib.h>
   4 #include <string.h>
   5 #include <sys/mount.h>
   6 #include <sys/stat.h>
   7 #include <unistd.h>
   8
   9 #include "cgroup.h"
  10
  11 void (*cgroup_perror)(const char *s) = perror;
  12 static const char cgroupfs[] = "/sys/fs/cgroup/";
  13
  14 int
  15 cgroup_setup(const char *chier, const char *controllers)
  16 {
  17         char chierdir[PATH_MAX];
  18         snprintf(chierdir, sizeof(chierdir), "%s%s", cgroupfs, chier);
  19         if (access(chierdir, F_OK) >= 0)
  20                 return 0;
  21
  22         if (mount("none", cgroupfs, "tmpfs", 0, NULL) < 0) {
  23                 cgroup_perror(cgroupfs);
  24                 return -1;
  25         }
  26         if (mkdir(chierdir, 0777) < 0) {
  27                 cgroup_perror(chierdir);
  28                 return -1;
  29         }
  30         if (mount("none", chierdir, "cgroup", 0, controllers) < 0) {
  31                 cgroup_perror(chierdir);
  32                 return -1;
  33         }
  34         return 1;
  35 }
  36
  37 int
  38 cgroup_create(const char *chier, const char *cgroup)
  39 {
  40         char cgroupdir[PATH_MAX];
  41         snprintf(cgroupdir, sizeof(cgroupdir), "%s%s/%s", cgroupfs, chier, cgroup);
  42         if (access(cgroupdir, F_OK) >= 0)
  43                 return 0;
  44         if (mkdir(cgroupdir, 0777) < 0) {
  45                 cgroup_perror(cgroupdir);
  46                 return -1;
  47         }
  48         return 1;
  49 }
  50
  51
  52 int
  53 cgroup_add_task(const char *chier, const char *cgroup, pid_t pid)
  54 {
  55         char tasksfile[PATH_MAX];
  56         snprintf(tasksfile, sizeof(tasksfile), "%s%s/%s/tasks", cgroupfs, chier, cgroup);
  57         FILE *tasks = fopen(tasksfile, "a");
  58         if (!tasks) {
  59                 cgroup_perror(tasksfile);
  60                 return -1;
  61         }
  62         fprintf(tasks, "%d\n", pid);
  63         fclose(tasks);
  64         return 1;
  65 }
  66
  67 int
  68 cgroup_is_task_in_cgroup(const char *chier, const char *cgroup, pid_t pid)
  69 {
  70         char tasksfile[PATH_MAX];
  71         snprintf(tasksfile, sizeof(tasksfile), "%s%s/%s/tasks", cgroupfs, chier, cgroup);
  72         FILE *tasks = fopen(tasksfile, "r");
  73         if (!tasks) {
  74                 cgroup_perror(tasksfile);
  75                 return -1;
  76         }
  77
  78         bool exists = false;
  79         char line[128];
  80         while (fgets(line, sizeof(line), tasks)) {
  81                 if (atoi(line) == pid) {
  82                         exists = true;
  83                         break;
  84                 }
  85         }
  86         fclose(tasks);
  87         return exists;
  88 }
  89
  90 int
  91 cgroup_task_list(const char *chier, const char *cgroup, pid_t **tasklist)
  92 {
  93         char tasksfile[PATH_MAX];
  94         snprintf(tasksfile, sizeof(tasksfile), "%s%s/%s/tasks", cgroupfs, chier, cgroup);
  95         FILE *tasks = fopen(tasksfile, "r");
  96         if (!tasks) {
  97                 cgroup_perror(tasksfile);
  98                 return -1;
  99         }
 100
 101         int ntasks = 0;
 102         *tasklist = NULL;
 103         char line[128];
 104         while (fgets(line, sizeof(line), tasks)) {
 105                 if (!(ntasks % 32))
 106                         *tasklist = realloc(*tasklist, (ntasks + 32) * sizeof(*tasklist));
 107                 (*tasklist)[ntasks++] = atoi(line);
 108         }
 109         fclose(tasks);
 110         return ntasks;
 111 }
 112
 113
 114 size_t
 115 cgroup_get_mem_limit(const char *chier, const char *cgroup)
 116 {
 117         char limitfile[PATH_MAX];
 118         snprintf(limitfile, sizeof(limitfile), "%s%s/%s/memory.limit_in_bytes", cgroupfs, chier, cgroup);
 119         FILE *limit = fopen(limitfile, "r");
 120         if (!limit) {
 121                 cgroup_perror(limitfile);
 122                 return -1;
 123         }
 124         size_t nlimit = 0;
 125         fscanf(limit, "%zu", &nlimit); /* FIXME is this really unsigned? */
 126         fclose(limit);
 127         return nlimit;
 128 }
 129
 130 int
 131 cgroup_set_mem_limit(const char *chier, const char *cgroup, size_t nlimit)
 132 {
 133         char limitfile[PATH_MAX];
 134         snprintf(limitfile, sizeof(limitfile), "%s%s/%s/memory.limit_in_bytes", cgroupfs, chier, cgroup);
 135         FILE *limit = fopen(limitfile, "w");
 136         if (!limit) {
 137                 cgroup_perror(limitfile);
 138                 return -1;
 139         }
 140         fprintf(limit, "%zu\n", nlimit);
 141         fclose(limit);
 142         return 1;
 143 }
 144
 145 size_t
 146 cgroup_get_mem_usage(const char *chier, const char *cgroup)
 147 {
 148         char usagefile[PATH_MAX];
 149         snprintf(usagefile, sizeof(usagefile), "%s%s/%s/memory.usage_in_bytes", cgroupfs, chier, cgroup);
 150         FILE *usage = fopen(usagefile, "r");
 151         if (!usage) {
 152                 cgroup_perror(usagefile);
 153                 return -1;
 154         }
 155         size_t nusage = 0;
 156         fscanf(usage, "%zu", &nusage);
 157         fclose(usage);
 158         return nusage;
 159 }