proc.c

   1 #define _GNU_SOURCE
   2 #include <sched.h>
   3 #include <sys/wait.h>
   4 #include <sys/types.h>
   5 #include <sys/resource.h>
   6 #include <unistd.h>
   7 #include <string.h>
   8 #include <errno.h>
   9
  10 #include "proc.h"
  11 #include "die.h"
  12
  13 void cpu_affinity(int cpu)
  14 {
  15         int ret;
  16         cpu_set_t cpu_bitmask;
  17
  18         CPU_ZERO(&cpu_bitmask);
  19         CPU_SET(cpu, &cpu_bitmask);
  20
  21         ret = sched_setaffinity(getpid(), sizeof(cpu_bitmask),
  22                                 &cpu_bitmask);
  23         if (ret)
  24                 panic("Can't set this cpu affinity!\n");
  25 }
  26
  27 int set_proc_prio(int priority)
  28 {
  29         int ret = setpriority(PRIO_PROCESS, getpid(), priority);
  30         if (ret)
  31                 panic("Can't set nice val to %i!\n", priority);
  32
  33         return 0;
  34 }
  35
  36 int set_sched_status(int policy, int priority)
  37 {
  38         int ret, min_prio, max_prio;
  39         struct sched_param sp;
  40
  41         max_prio = sched_get_priority_max(policy);
  42         min_prio = sched_get_priority_min(policy);
  43
  44         if (max_prio == -1 || min_prio == -1)
  45                 printf("Cannot determine scheduler prio limits!\n");
  46         else if (priority < min_prio)
  47                 priority = min_prio;
  48         else if (priority > max_prio)
  49                 priority = max_prio;
  50
  51         memset(&sp, 0, sizeof(sp));
  52         sp.sched_priority = priority;
  53
  54         ret = sched_setscheduler(getpid(), policy, &sp);
  55         if (ret) {
  56                 printf("Cannot set scheduler policy!\n");
  57                 return -EINVAL;
  58         }
  59
  60         ret = sched_setparam(getpid(), &sp);
  61         if (ret) {
  62                 printf("Cannot set scheduler prio!\n");
  63                 return -EINVAL;
  64         }
  65
  66         return 0;
  67 }
  68
  69 ssize_t proc_get_cmdline(unsigned int pid, char *cmdline, size_t len)
  70 {
  71         ssize_t ret;
  72         char path[1024];
  73
  74         snprintf(path, sizeof(path), "/proc/%u/exe", pid);
  75         ret = readlink(path, cmdline, len - 1);
  76         if (ret < 0)
  77                 cmdline[0] = '\0';
  78         else
  79                 cmdline[ret] = '\0';
  80
  81         return ret;
  82 }
  83
  84 int proc_exec(const char *proc, char *const argv[])
  85 {
  86         int status;
  87         pid_t pid;
  88
  89         pid = fork();
  90         if (pid < 0) {
  91                 perror("fork");
  92                 return -1;
  93         } else if (pid == 0) {
  94                 if (execvp(proc, argv) < 0)
  95                         fprintf(stderr, "Failed to exec: %s\n", proc);
  96                 _exit(1);
  97         }
  98
  99         if (waitpid(pid, &status, 0) < 0) {
 100                 perror("waitpid");
 101                 return -2;
 102         }
 103
 104         if (!WIFEXITED(status))
 105                 return -WEXITSTATUS(status);
 106
 107         return 0;
 108 }