source/misc.cpp

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