/*

 * Copyright (C) 2004 The X.Org fundation

 * 

 * Permission is hereby granted, free of charge, to any person

 * obtaining a copy of this software and associated documentation

 * files (the "Software"), to deal in the Software without

 * restriction, including without limitation the rights to use, copy,

 * modify, merge, publish, distribute, sublicense, and/or sell copies

 * of the Software, and to permit persons to whom the Software is fur-

 * nished to do so, subject to the following conditions:

 * 

 * The above copyright notice and this permission notice shall be

 * included in all copies or substantial portions of the Software.

 * 

 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,

 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF

 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND

 * NONINFRINGEMENT.  IN NO EVENT SHALL THE X CONSORTIUM BE LIABLE FOR

 * ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF

 * CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION

 * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

 * 

 * Except as contained in this notice, the name of the X.Org fundation

 * shall not be used in advertising or otherwise to promote the sale,

 * use or other dealings in this Software without prior written

 * authorization from the X.Org fundation.

 */

/*

** This is a secure but NOT 100% compatible replacement for popen()

** Note:        - don't use pclose() use fclose() for closing the returned

**                filedesc.!!!

**

** Known Bugs:  - unable to use i/o-redirection like > or <

** Author:      - Thomas Biege <thomas@suse.de>

** Credits:     - Andreas Pfaller <a.pfaller@pop.gun.de> for fixing a SEGV when

**                calling strtok()

*/

#include <sys/types.h>

#include <sys/wait.h>

#include <stdio.h>

#include <stdlib.h>

#include <unistd.h>

#include <string.h>

#define __SEC_POPEN_TOKEN " "

FILE *Xpms_popen(char *cmd, const char *type)

{

  pid_t pid;

  int pfd[2];

  int rpipe = 0, wpipe = 0, i;

  char **argv;

  char *ptr;

  char *cmdcpy;

  if(cmd == NULL || cmd == "")

    return(NULL);

  if(type[0] != 'r' && type[0] != 'w')

    return(NULL);

  if ((cmdcpy = strdup(cmd)) == NULL)

    return(NULL);

  argv = NULL;

  if( (ptr = strtok(cmdcpy, __SEC_POPEN_TOKEN)) == NULL)

  {

    free(cmdcpy);

    return(NULL);

  }

  for(i = 0;; i++)

  {

    if( ( argv = (char **) realloc(argv, (i+1) * sizeof(char *)) ) == NULL)

    {

      free(cmdcpy);

      return(NULL);

    }

    if( (*(argv+i) = (char *) malloc((strlen(ptr)+1) * sizeof(char))) == NULL)

    {

      free(cmdcpy);

      return(NULL);

    }

    strcpy(argv[i], ptr);

    if( (ptr = strtok(NULL, __SEC_POPEN_TOKEN)) == NULL)

    {

      if( ( argv = (char **) realloc(argv, (i+2) * sizeof(char *))) == NULL)

      {

        free(cmdcpy);

        return(NULL);

      }

      argv[i+1] = NULL;

      break;

    }

  }

  if(type[0] == 'r')

    rpipe = 1;

  else

    wpipe = 1;

  if (pipe(pfd) < 0)

  {

    free(cmdcpy);

    return(NULL);

  }

	if((pid = fork()) < 0)

  {

    close(pfd[0]);

    close(pfd[1]);

    free(cmdcpy);

    return(NULL);

  }

	if(pid == 0)    /* child */

  {

    if((pid = fork()) < 0)

    {

      close(pfd[0]);

      close(pfd[1]);

      free(cmdcpy);

      return(NULL);

    }

    if(pid > 0)

    {

      exit(0);  /* child nr. 1 exits */

    }

    /* child nr. 2 */

    if(rpipe)

    {

      close(pfd[0]);  /* close reading end, we don't need it */

      dup2(STDOUT_FILENO, STDERR_FILENO);

      if (pfd[1] != STDOUT_FILENO)

        dup2(pfd[1], STDOUT_FILENO);  /* redirect stdout to writing end of pipe */

    }

    else

    {

      close(pfd[1]);  /* close writing end, we don't need it */

      if (pfd[0] != STDIN_FILENO)

        dup2(pfd[0], STDIN_FILENO);    /* redirect stdin to reading end of pipe */

	  }

    if(strchr(argv[0], '/') == NULL)

      execvp(argv[0], argv);  /* search in $PATH */

    else

      execv(argv[0], argv);

    close(pfd[0]);

    close(pfd[1]);

    free(cmdcpy);

    return(NULL);  /* exec failed.. ooops! */

  }

  else          /* parent */

  {

    waitpid(pid, NULL, 0); /* wait for child nr. 1 */

    if(rpipe)

    {

      close(pfd[1]);

      free(cmdcpy);

      return(fdopen(pfd[0], "r"));

    }

    else

    {

      close(pfd[0]);

      free(cmdcpy);

      return(fdopen(pfd[1], "w"));

    }

  }

}