src/Backend/inc_solver.cc

   1 /*      Copyright (c) 2015 Regents of the University of California
   2  *
   3  *      Author: Brian Demsky <bdemsky@uci.edu>
   4  *
   5  *      This program is free software; you can redistribute it and/or
   6  *      modify it under the terms of the GNU General Public License
   7  *      version 2 as published by the Free Software Foundation.
   8  */
   9
  10 #include "inc_solver.h"
  11 #define SATSOLVER "sat_solver"
  12 #include <fcntl.h>
  13 #include "common.h"
  14 #include <string.h>
  15
  16 IncrementalSolver *allocIncrementalSolver() {
  17         IncrementalSolver *This = (IncrementalSolver *)ourmalloc(sizeof(IncrementalSolver));
  18         This->buffer = ((int *)ourmalloc(sizeof(int) * IS_BUFFERSIZE));
  19         This->solution = NULL;
  20         This->solutionsize = 0;
  21         This->offset = 0;
  22         This->timeout = NOTIMEOUT;
  23         createSolver(This);
  24         return This;
  25 }
  26
  27 void deleteIncrementalSolver(IncrementalSolver *This) {
  28         killSolver(This);
  29         ourfree(This->buffer);
  30         if (This->solution != NULL)
  31                 ourfree(This->solution);
  32         ourfree(This);
  33 }
  34
  35 void resetSolver(IncrementalSolver *This) {
  36         killSolver(This);
  37         This->offset = 0;
  38         createSolver(This);
  39 }
  40
  41 void addClauseLiteral(IncrementalSolver *This, int literal) {
  42         This->buffer[This->offset++] = literal;
  43         if (This->offset == IS_BUFFERSIZE) {
  44                 flushBufferSolver(This);
  45         }
  46 }
  47
  48 void addArrayClauseLiteral(IncrementalSolver *This, uint numliterals, int *literals) {
  49         uint index = 0;
  50         while (true) {
  51                 uint bufferspace = IS_BUFFERSIZE - This->offset;
  52                 uint numtowrite = numliterals - index;
  53                 if (bufferspace > numtowrite) {
  54                         memcpy(&This->buffer[This->offset], &literals[index], numtowrite * sizeof(int));
  55                         This->offset += numtowrite;
  56                         This->buffer[This->offset++] = 0;       //have one extra spot always
  57                         if (This->offset == IS_BUFFERSIZE) {//Check if full
  58                                 flushBufferSolver(This);
  59                         }
  60                         return;
  61                 } else {
  62                         memcpy(&This->buffer[This->offset], &literals[index], bufferspace * sizeof(int));
  63                         This->offset += bufferspace;
  64                         index += bufferspace;
  65                         flushBufferSolver(This);
  66                 }
  67         }
  68 }
  69
  70 void finishedClauses(IncrementalSolver *This) {
  71         This->buffer[This->offset++] = 0;
  72         if (This->offset == IS_BUFFERSIZE) {
  73                 flushBufferSolver(This);
  74         }
  75 }
  76
  77 void freeze(IncrementalSolver *This, int variable) {
  78         addClauseLiteral(This, IS_FREEZE);
  79         addClauseLiteral(This, variable);
  80 }
  81
  82 int solve(IncrementalSolver *This) {
  83         //add an empty clause
  84         startSolve(This);
  85         return getSolution(This);
  86 }
  87
  88 void startSolve(IncrementalSolver *This) {
  89         addClauseLiteral(This, IS_RUNSOLVER);
  90         flushBufferSolver(This);
  91 }
  92
  93 int getSolution(IncrementalSolver *This) {
  94         int result = readStatus(This);
  95         if (result == IS_SAT) {
  96                 int numVars = readIntSolver(This);
  97                 if (numVars > This->solutionsize) {
  98                         if (This->solution != NULL)
  99                                 ourfree(This->solution);
 100                         This->solution = (int *) ourmalloc((numVars + 1) * sizeof(int));
 101                         This->solution[0] = 0;
 102                 }
 103                 readSolver(This, &This->solution[1], numVars * sizeof(int));
 104                 This->solutionsize = numVars;
 105         }
 106         return result;
 107 }
 108
 109 int readIntSolver(IncrementalSolver *This) {
 110         int value;
 111         readSolver(This, &value, 4);
 112         return value;
 113 }
 114
 115 int readStatus(IncrementalSolver *This) {
 116         int retval;
 117         fd_set rfds;
 118         FD_ZERO(&rfds);
 119         FD_SET(This->from_solver_fd, &rfds);
 120         fd_set * temp;
 121         if(This->timeout == NOTIMEOUT){
 122                 retval = select(This->from_solver_fd+1, &rfds, NULL, NULL, NULL);
 123         }else {
 124                 struct timeval tv;
 125                 tv.tv_sec = This->timeout;
 126                 tv.tv_usec = 0;
 127                 retval = select(This->from_solver_fd+1, &rfds, NULL, NULL, &tv);
 128         }
 129         if(retval == -1){
 130                 perror("Error in select()");
 131                 exit(EXIT_FAILURE);
 132         }
 133         else if (retval){
 134                 printf("Data is available now.\n");
 135                 return readIntSolver(This);
 136         }else{
 137                 printf("Timeout for the solver\n");
 138                 return IS_INDETER;
 139         }
 140 }
 141
 142 void readSolver(IncrementalSolver *This, void *tmp, ssize_t size) {
 143         char *result = (char *) tmp;
 144         ssize_t bytestoread = size;
 145         ssize_t bytesread = 0;
 146         do {
 147                 ssize_t n = read(This->from_solver_fd, &((char *)result)[bytesread], bytestoread);
 148                 if (n == -1) {
 149                         model_print("Read failure\n");
 150                         exit(-1);
 151                 }
 152                 bytestoread -= n;
 153                 bytesread += n;
 154         } while (bytestoread != 0);
 155 }
 156
 157 bool getValueSolver(IncrementalSolver *This, int variable) {
 158         return This->solution[variable];
 159 }
 160
 161 void createSolver(IncrementalSolver *This) {
 162         int to_pipe[2];
 163         int from_pipe[2];
 164         if (pipe(to_pipe) || pipe(from_pipe)) {
 165                 model_print("Error creating pipe.\n");
 166                 exit(-1);
 167         }
 168         if ((This->solver_pid = fork()) == -1) {
 169                 model_print("Error forking.\n");
 170                 exit(-1);
 171         }
 172         if (This->solver_pid == 0) {
 173                 //Solver process
 174                 close(to_pipe[1]);
 175                 close(from_pipe[0]);
 176                 int fd = open("log_file", O_WRONLY | O_CREAT | O_TRUNC, S_IRWXU);
 177
 178                 if ((dup2(to_pipe[0], 0) == -1) ||
 179                                 (dup2(from_pipe[1], IS_OUT_FD) == -1) ||
 180                                 (dup2(fd, 1) == -1)) {
 181                         model_print("Error duplicating pipes\n");
 182                 }
 183                 //    setsid();
 184                 execlp(SATSOLVER, SATSOLVER, NULL);
 185                 model_print("execlp Failed\n");
 186                 close(fd);
 187         } else {
 188                 //Our process
 189                 This->to_solver_fd = to_pipe[1];
 190                 This->from_solver_fd = from_pipe[0];
 191                 close(to_pipe[0]);
 192                 close(from_pipe[1]);
 193         }
 194 }
 195
 196 void killSolver(IncrementalSolver *This) {
 197         close(This->to_solver_fd);
 198         close(This->from_solver_fd);
 199         //Stop the solver
 200         if (This->solver_pid > 0) {
 201                 int status;
 202                 kill(This->solver_pid, SIGKILL);
 203                 waitpid(This->solver_pid, &status, 0);
 204         }
 205 }
 206
 207 //DEBUGGING CODE STARTS
 208 bool first = true;
 209 //DEBUGGING CODE ENDS
 210
 211 void flushBufferSolver(IncrementalSolver *This) {
 212         ssize_t bytestowrite = sizeof(int) * This->offset;
 213         ssize_t byteswritten = 0;
 214 #ifdef CONFIG_DEBUG
 215         for (uint i = 0; i < This->offset; i++) {
 216                 if (first)
 217                         printf("(");
 218                 if (This->buffer[i] == 0) {
 219                         printf(")\n");
 220                         first = true;
 221                 } else {
 222                         if (!first)
 223                                 printf(" + ");
 224                         first = false;
 225                         printf("%d", This->buffer[i]);
 226                 }
 227         }
 228 #endif
 229         do {
 230                 ssize_t n = write(This->to_solver_fd, &((char *)This->buffer)[byteswritten], bytestowrite);
 231                 if (n == -1) {
 232                         perror("Write failure\n");
 233                         model_print("to_solver_fd=%d\n",This->to_solver_fd);
 234                         exit(-1);
 235                 }
 236                 bytestowrite -= n;
 237                 byteswritten += n;
 238         } while (bytestowrite != 0);
 239         This->offset = 0;
 240 }