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   int r, status;
  29
  30   if (!child) return;
  31
  32   r= waitpid(child,&status,WNOHANG); if (!r) return;
  33   if (r==-1) {
  34     Message(M_ERR,"hacky_par: waitpid: %s\n",strerror(errno));
  35     return;
  36   }
  37   child= 0;
  38
  39   if (WIFSIGNALED(status)) {
  40     Message(M_ERR,"hacky_par: signaled! %s\n",strsignal(WTERMSIG(status)));
  41   } else if (!WIFEXITED(status)) {
  42     Message(M_ERR,"hacky_par: unexpected status! %d\n", r);
  43   }
  44 }
  45
  46 static HPState start(void) {
  47   assert(!child);
  48
  49   child= fork();
  50   if (child == -1) {
  51     Message(M_ERR,"hacky_par: fork failed: %s\n",strerror(errno));
  52     return hp_fail;
  53   }
  54
  55   if (!child) { /* we are the child */
  56     return hp_compute;
  57   }
  58
  59   Message(M_INFO,"hacky_par: started, punting\n");
  60   return hp_deferring;
  61 }
  62
  63 int hacky_par_start_failnow(void) {
  64   state= hp_idle;
  65   checkchild();
  66   if (child) {
  67     state= hp_deferring;
  68     Message(M_INFO,"hacky_par: busy, punting\n");
  69     return 1;
  70   }
  71   return 0;
  72 }
  73
  74 int hacky_par_mid_failnow(void) {
  75   state= start();
  76   return state != hp_compute;
  77 }
  78
  79 bool_t (*packy_par_gen)(struct site *st);
  80
  81 void hacky_par_end(int *ok,
  82                    int32_t retries, int32_t timeout,
  83                    bool_t (*send_msg)(struct site *st), struct site *st) {
  84   int i;
  85
  86   switch (state) {
  87   case hp_deferring:
  88     assert(!*ok);
  89     *ok= 1;
  90     return;
  91   case hp_fail:
  92     assert(!*ok);
  93     return;
  94   case hp_idle:
  95     return;
  96   case hp_compute:
  97     if (!ok) {
  98       Message(M_ERR,"hacky_par: compute failed\n");
  99       _exit(2);
 100     }
 101     Message(M_INFO,"hacky_par: got result, sending\n");
 102     for (i=1; i<retries; i++) {
 103         sleep((timeout + 999)/1000);
 104         if (!send_msg(st)) {
 105             Message(M_ERR,"hacky_par: retry failed\n");
 106             _exit(1);
 107         }
 108     }
 109     _exit(0);
 110   }
 111 }
 112
 113 #else /*!HACKY_PARALLEL*/
 114
 115 int hacky_par_start_failnow(void) { return 0; }
 116 int hacky_par_mid_failnow(void) { return 0; }
 117 void hacky_par_end(int *ok,
 118                    int32_t retries, int32_t timeout,
 119                    bool_t (*send_msg)(struct site *st), struct site *st) { }
 120
 121 #endif /*HACKY_PARALLEL...else*/