mdw@git.distorted.org.uk Git - secnet/blob - hackypar.c

   1 /* Hacky parallelism; Ian Jackson */
   2
   3 #define _GNU_SOURCE
   4
   5 #include "secnet.h"
   6 #include "util.h"
   7 #include "hackypar.h"
   8
   9 #ifdef HACKY_PARALLEL
  10
  11 #include <stdio.h>
  12 #include <unistd.h>
  13 #include <errno.h>
  14 #include <string.h>
  15 #include <signal.h>
  16 #include <assert.h>
  17 #include <sys/wait.h>
  18
  19 #define HASHSIZE 16
  20 #define CACHESIZE 16
  21
  22 typedef enum { hp_idle, hp_compute, hp_deferring, hp_fail } HPState;
  23
  24 static HPState state;
  25 static pid_t child;
  26
  27 static void checkchild(void)
  28 {
  29     int r, status;
  30
  31     if (!child) return;
  32
  33     r= waitpid(child,&status,WNOHANG); if (!r) return;
  34     if (r==-1) {
  35         Message(M_ERR,"hacky_par: waitpid: %s\n",strerror(errno));
  36         return;
  37     }
  38     child= 0;
  39
  40     if (WIFSIGNALED(status)) {
  41         Message(M_ERR,"hacky_par: signaled! %s\n",strsignal(WTERMSIG(status)));
  42     } else if (!WIFEXITED(status)) {
  43         Message(M_ERR,"hacky_par: unexpected status! %d\n", r);
  44     }
  45 }
  46
  47 static HPState start(void)
  48 {
  49     assert(!child);
  50
  51     child= fork();
  52     if (child == -1) {
  53         Message(M_ERR,"hacky_par: fork failed: %s\n",strerror(errno));
  54         return hp_fail;
  55     }
  56
  57     if (!child) { /* we are the child */
  58         return hp_compute;
  59     }
  60
  61     Message(M_INFO,"hacky_par: started, punting\n");
  62     return hp_deferring;
  63 }
  64
  65 int hacky_par_start_failnow(void)
  66 {
  67     state= hp_idle;
  68     checkchild();
  69     if (child) {
  70         state= hp_deferring;
  71         Message(M_INFO,"hacky_par: busy, punting\n");
  72         return 1;
  73     }
  74     return 0;
  75 }
  76
  77 int hacky_par_mid_failnow(void)
  78 {
  79     state= start();
  80     return state != hp_compute;
  81 }
  82
  83 bool_t (*packy_par_gen)(struct site *st);
  84
  85 void hacky_par_end(int *ok,
  86                    int32_t retries, int32_t timeout,
  87                    bool_t (*send_msg)(struct site *st), struct site *st)
  88 {
  89     int i;
  90
  91     switch (state) {
  92     case hp_deferring:
  93         assert(!*ok);
  94         *ok= 1;
  95         return;
  96     case hp_fail:
  97         assert(!*ok);
  98         return;
  99     case hp_idle:
 100         return;
 101     case hp_compute:
 102         if (!ok) {
 103             Message(M_ERR,"hacky_par: compute failed\n");
 104             _exit(2);
 105         }
 106         Message(M_INFO,"hacky_par: got result, sending\n");
 107         for (i=1; i<retries; i++) {
 108             sleep((timeout + 999)/1000);
 109             if (!send_msg(st)) {
 110                 Message(M_ERR,"hacky_par: retry failed\n");
 111                 _exit(1);
 112             }
 113         }
 114         _exit(0);
 115     }
 116 }
 117
 118 #else /*!HACKY_PARALLEL*/
 119
 120 int hacky_par_start_failnow(void) { return 0; }
 121 int hacky_par_mid_failnow(void) { return 0; }
 122 void hacky_par_end(int *ok,
 123                    int32_t retries, int32_t timeout,
 124                    bool_t (*send_msg)(struct site *st), struct site *st) { }
 125
 126 #endif /*HACKY_PARALLEL...else*/