source/misc.cpp

   1 #include <iostream>
   2 #include <sys/wait.h>
   3 #include "misc.h"
   4
   5 using namespace std;
   6 using namespace Msp;
   7
   8 /**
   9 Runs a command and returns its output as a string.  The exit status of the
  10 command is lost.
  11 */
  12 string run_command(const StringList &argv)
  13 {
  14         int pfd[2];
  15         pipe(pfd);
  16
  17         string result;
  18
  19         pid_t pid=fork();
  20         if(pid==0)
  21         {
  22                 char *argv_[argv.size()+1];
  23
  24                 unsigned j=0;
  25                 for(StringList::const_iterator i=argv.begin(); i!=argv.end(); ++i)
  26                         argv_[j++]=strdup(i->c_str());
  27                 argv_[j]=0;
  28
  29                 close(pfd[0]);
  30                 dup2(pfd[1], 1);
  31                 dup2(pfd[1], 2);
  32
  33                 execvp(argv_[0], argv_);
  34                 ::exit(1);
  35         }
  36         else if(pid==-1)
  37                 cerr<<"Failed to execute "<<argv.front()<<'\n';
  38         else
  39         {
  40                 close(pfd[1]);
  41                 while(1)
  42                 {
  43                         char buf[1024];
  44                         int len=read(pfd[0], buf, sizeof(buf));
  45                         if(len<=0)
  46                         {
  47                                 if(waitpid(pid, 0, WNOHANG))
  48                                         break;
  49                         }
  50                         else
  51                                 result.append(buf, len);
  52                 }
  53         }
  54
  55         return result;
  56 }
  57
  58