src/main.cpp

   1 #include <stdlib.h>
   2 #include <stdio.h>
   3 #include <string.h>
   4 #include <time.h>
   5 #include <unistd.h>
   6
   7 #include <sys/wait.h>
   8 #include <sys/types.h>
   9
  10
  11
  12 #define ERR_WRONGARGS   -1
  13 #define ERR_EXECVE      -2
  14 #define ERR_FORK        -3
  15 #define ERR_WAITPID     -4
  16 #define ERR_KILL        -5
  17
  18
  19
  20 void printUsage(FILE* out, int argc, char** argv)
  21 {
  22         fprintf(out, "Run command <command> for at least a specific time. Kill\n");
  23         fprintf(out, "process executing <command> if time is over. \n");
  24         fprintf(out, "\n");
  25         fprintf(out, "Usage: %s [options] <command>\n", argv[0]);
  26         fprintf(out, "\n");
  27         fprintf(out, "Options:\n");
  28         fprintf(out, "  -h        Print this help.\n");
  29         fprintf(out, "  -t <sec>  Number of seconds.\n");
  30         fprintf(out, "  -v        Be verbose.\n");
  31 }
  32
  33
  34 int main(int argc, char** argv)
  35 {
  36         bool argHelp=false;
  37         bool argTime=false;
  38         bool argVerbose=false;
  39         float maxtime=0;
  40
  41         //Wrong arguments
  42         if( argc<=1 )
  43         {
  44                 printUsage(stderr, argc, argv);
  45                 return ERR_WRONGARGS;
  46         }
  47
  48
  49         //Get the argument index of the head of <command>
  50         int fiarg=1;
  51
  52         //Aha, argument -- skip it
  53         while( fiarg<argc && strncmp(argv[fiarg], "-", 1)==0 )
  54         {
  55                 //Help option
  56                 if( strncmp(argv[fiarg], "-h", 2) == 0 )
  57                 {
  58                         argHelp = true;
  59                 }
  60
  61                 //Parse time
  62                 else if( strncmp(argv[fiarg], "-t", 2) == 0 )
  63                 {
  64                         //Time is given -- goto next argument
  65                         argTime=true;
  66                         fiarg++;
  67                         if( fiarg >= argc)
  68                         {
  69                                 fprintf(stderr, "Missing time.\n");
  70                                 fprintf(stderr, "\n");
  71                                 printUsage(stderr, argc, argv);
  72                                 return ERR_WRONGARGS;
  73                         }
  74
  75                         //Convert the time given in seconds to float
  76                         char* endptr;
  77                         maxtime = strtof( argv[fiarg], &endptr);
  78                         if( endptr != argv[fiarg] + strlen(argv[fiarg]) ||
  79                                 maxtime<0.0)
  80                         {
  81                                 fprintf(stderr, "Invalid time.\n");
  82                                 fprintf(stderr, "\n");
  83                                 printUsage(stderr, argc, argv);
  84                                 return ERR_WRONGARGS;
  85                         }
  86                 }
  87
  88                 //Help option
  89                 else if( strncmp(argv[fiarg], "-v", 2) == 0 )
  90                 {
  91                         argVerbose = true;
  92                 }
  93
  94
  95                 //Unknown option
  96                 else
  97                 {
  98                         fprintf(stderr, "Invalid argument: %s\n", argv[fiarg]);
  99                         fprintf(stderr, "\n");
 100                         printUsage(stderr, argc, argv);
 101                         return ERR_WRONGARGS;
 102                 }
 103
 104                 //Goto next argument
 105                 fiarg++;
 106         }
 107
 108
 109         //Print help
 110         if( argHelp )
 111         {
 112                 printUsage(stdout, argc, argv);
 113                 return 0;
 114         }
 115
 116
 117         //No time given...
 118         if( !argTime )
 119         {
 120                 fprintf(stderr, "No time given!\n");
 121                 fprintf(stderr, "\n");
 122                 printUsage(stderr, argc, argv);
 123                 return ERR_WRONGARGS;
 124         }
 125
 126         //No command left
 127         if( fiarg>=argc )
 128         {
 129                 fprintf(stderr, "No command given!\n");
 130                 fprintf(stderr, "\n");
 131                 printUsage(stderr, argc, argv);
 132                 return ERR_WRONGARGS;
 133         }
 134
 135
 136
 137         //Fork process
 138         pid_t pid = fork();
 139
 140
 141         //Childrens code...
 142         if( pid == 0)
 143         {
 144                 char** newargv = (char**) malloc( sizeof(char*)*(argc-fiarg+1) );
 145                 char* newenv[] = {NULL};
 146
 147                 //Copy arguments
 148                 for( int i=fiarg; i<argc; i++)
 149                 {
 150                         newargv[i-fiarg] = (char*)malloc(strlen(argv[i])+1);
 151                         strcpy(newargv[i-fiarg], argv[i]);
 152                 }
 153                 newargv[argc-fiarg] = NULL;
 154
 155
 156                 //Execute child process
 157                 execve(newargv[0], newargv, newenv);
 158                 perror("execve");
 159                 return ERR_EXECVE;
 160         }
 161         //Parents code...
 162         else
 163         {
 164                 //Failure
 165                 if(pid==-1)
 166                 {
 167                         perror("fork");
 168                         return ERR_FORK;
 169                 }
 170
 171
 172                 //Nmb of loops=seconds
 173                 float loops=0;
 174                 //Status flags of child process
 175                 int status, w;
 176
 177                 do
 178                 {
 179                         //Kill the child
 180                         if( loops >= maxtime )
 181                         {
 182                                 if( argVerbose )
 183                                         printf("Kill child...\n");
 184
 185                                 if( kill(pid, SIGTERM ) < 0)
 186                                         break;
 187                         }
 188
 189                         //Sleep a round
 190                         sleep(1);
 191                         loops++;
 192
 193                         //Test for child
 194                         if( waitpid(-1, &status, WNOHANG | WUNTRACED | WCONTINUED) < 0 )
 195                                 break;
 196
 197                 }while( !WIFEXITED(status) );
 198         }
 199
 200
 201         if( argVerbose)
 202                 printf("Finished\n");
 203
 204         return 0;
 205 }
 206
 207