System commands from c

[Fernando RUIZ CASAS]

On Mon, 10 May 2004 15:27:14 -0600, Steve Holle wrote:

> 
> I there any way to issue a file system command from within c, such as 'ls'?

Hi,
  at 

http://www.rtems.com/cgi-bin/cvsweb.cgi/rtems/cpukit/libmisc/shell/cmds.c?rev=1.17&content-type=text/x-cvsweb-markup

you can see this & more ready to use.

int main_ls(int argc, char *argv[])
{
   char * fname;
   DIR                 *dirp;
   struct dirent       *dp;
   struct stat         stat_buf;
   struct passwd     * pwd;
   struct group      * grp;
   char * user;
   char * group;
   char   sbuf[256];
   char   nbuf[1024];
   int  n,size;

   fname=".";
   if (argc>1) fname=argv[1];

   if ((dirp = opendir(fname)) == NULL)
   {
      fprintf(stdout,"%s: No such file or directory.\n", fname);
      return errno;
   }
   n=0;
   size=0;
   while ((dp = readdir(dirp)) != NULL)
   {
      strcpy(nbuf,fname);
      if (nbuf[strlen(nbuf)-1]!='/') strcat(nbuf,"/");
      strcat(nbuf,dp->d_name); /* always the fullpathname. Avoid ftpd problem.*/
      if (stat(nbuf, &stat_buf) == 0)
      { /* AWFUL buts works...*/
         strftime(sbuf,sizeof(sbuf)-1,"%b %d %H:%M",gmtime(&stat_buf.st_mtime));
         pwd=getpwuid(stat_buf.st_uid);
         user=pwd?pwd->pw_name:"nouser";
         grp=getgrgid(stat_buf.st_gid);
         group=grp?grp->gr_name:"nogrp";
         fprintf(stdout,"%c%c%c%c%c%c%c%c%c%c %3d %6.6s %6.6s %11d %s %s%c\n",
                 (S_ISLNK(stat_buf.st_mode)?('l'):
                    (S_ISDIR(stat_buf.st_mode)?('d'):('-'))),
                 (stat_buf.st_mode & S_IRUSR)?('r'):('-'),
                 (stat_buf.st_mode & S_IWUSR)?('w'):('-'),
                 (stat_buf.st_mode & S_IXUSR)?('x'):('-'),
                 (stat_buf.st_mode & S_IRGRP)?('r'):('-'),
                 (stat_buf.st_mode & S_IWGRP)?('w'):('-'),
                 (stat_buf.st_mode & S_IXGRP)?('x'):('-'),
                 (stat_buf.st_mode & S_IROTH)?('r'):('-'),
                 (stat_buf.st_mode & S_IWOTH)?('w'):('-'),
                 (stat_buf.st_mode & S_IXOTH)?('x'):('-'),
                 (int)stat_buf.st_nlink,
                  user,group,
                 (int)stat_buf.st_size,
                 sbuf,
                 dp->d_name,
                 S_ISDIR(stat_buf.st_mode)?'/':' ');
         n++;
         size+=stat_buf.st_size;
      }
   }
   fprintf(stdout,"%d files %d bytes occupied\n",n,size);
   closedir(dirp);
   return 0;
}