/* -------------------- SAS/C Sample Program --------------------
 *
 * MODULE: rexeccmd.c - Main routine for sample rexec command
 * SYNTAX: rexec host username password cmd-words
 *
 * NOTE:   This command does not support sending input to the remote
 *         program. Non-UNIX implementations often restrict
 *         select() to sockets. Thus, there is no portable
 *         way to wait for sockets and "stdin" simultaneously.
 */
#include <sys/types.h>
#include <sys/socket.h>
#include <netdb.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
 
#ifdef __SASC__
static void to_ebcdic(char *buf, size_t n);
#endif
 
#define EXEC_PORT 512  /* Well-know port for exec server. */
 
main(int argc, char *argv[])
{
   int primary;     /* Socket for stdin/stdout. */
   int secondary;   /* Socket for stderr. */
   fd_set read_set; /* Set of sockets we will wait on. */
   char buf[256];   /* Set of buffer for incoming data. */
 
   char *host;      /* Pointer to hostname. */
   int port;        /* Port for exec server */
   char cmd[512];   /* Command string. */
   struct servent *serv; /* exec server information. */
   int i, n, rc;
 
   /*
    * Handle command line arguments.
    *    argv[1] = hostname
    *    argv[2] = username
    *    argv[3] = password
    *    argv[4] = first command word
    *    ...
    *    argv[argc-1] = last command word
    */
   if (argc <5 || *argv[1]=='?' || strcmp(argv[1],"-?")==0) {
      printf("Usage: %s hostname username password cmd-words\n",
                argv[0]);
      exit(EXIT_FAILURE);
   }
   host = argv[1];  /* Pointer can be modified by rexec() call. */
 
   /* Build up command string from remaining arguments. */
   strcpy(cmd,argv[4]);
   for (i=5; i<argc; i++) {
      strcat(cmd," ");
      strcat(cmd,argv[i]);
   }
 
   /* Lookup standard REXEC server port. */
   serv = getservbyname("exec","tcp");
   if (serv==NULL) {
      perror("getservbyname failed");
      port = EXEC_PORT;  /* Assume the usual. */
   }
   else
      port = serv->s_port;
 
   primary = rexec(&host, port, argv[2], argv[3], cmd, &secondary);
   if (primary<0) return EXIT_FAILURE;
 
   FD_ZERO(&read_set);
   while (primary>=0 || secondary>=0) {
      /*
       * Wait for incoming data on both sockets.
       *   select() clears bits from the mask, so we must reset
       *   the bits each time through the loop.
       */
      if (primary>=0) FD_SET(primary, &read_set);
      if (secondary>=0) FD_SET(secondary, &read_set);
 
      rc = select(FD_SETSIZE, &read_set, NULL, NULL, NULL);
      if (rc<0) {
         perror("select failed");
         exit(EXIT_FAILURE);
      }
 
      /*
       * If incoming data available on primary...
       */
      if (primary >= 0 /* Not end of file yet. */
      &&  FD_ISSET(primary, &read_set)) {
         /* read it (or at least some of it). */
         n = read(primary, buf, sizeof(buf));
         if (n==0)
            primary = -1;  /* Flag end-of-file on primary. */
         else if (n<0) {
            perror("read failed on remote program's standard output");
            exit(EXIT_FAILURE);
         }
         else {
            #ifdef __SASC__
            to_ebcdic(buf, n);
            #endif
            fwrite(buf, n, 1, stdout); /* Write to local stdout */
         }
      }
      /*
       * If incoming data available on secondary...
       */
      if (secondary >= 0  /* Not end of file yet. */
      &&  FD_ISSET(secondary, &read_set)) {
         n = read(secondary, buf, sizeof(buf)-1);
         if (n==0)
            secondary = -1;  /* Flag end-of-file on secondary. */
         else if (n<0) {
            perror("read failed on remote program's standard error");
            exit(EXIT_FAILURE);
         }
         else {
            #ifdef __SASC__
            to_ebcdic(buf, n);
            #endif
            fwrite(buf, n, 1, stderr); /* Write to local stderr */
         }
      }
   }  /* End of while loop. */
 
   return EXIT_SUCCESS;
}
 
#ifdef __SASC__   /* Need conversion to EBCDIC */
#include <netinet/in.h> /* prototype for htoncs(). */
static void to_ebcdic(char *buf, size_t n)
{
   int i;
   /*
    * htoncs() is a SAS/C specific function which converts
    *   a character from ASCII to EBCDIC.
    */
   for (i=0; i<n; i++) buf[i] = ntohcs(buf[i]);
   return;
}
#endif