parseline.c

/*
   General line parsing routine

   Copyright (C) Stephen Fegan 1995, 1996

   This program is free software; you can redistribute it and/or modify it under
   the terms of the GNU General Public License as published by the Free Software
   Foundation; either version 2 of the License, or (at your option) any later
   version.
   
   This program is distributed in the hope that it will be useful, but WITHOUT
   ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
   FOR A PARTICULAR PURPOSE.  See the GNU General Public License for more
   details.
   
   You should have received a copy of the GNU General Public License along with
   this program; if not, write to the Free Software Foundation, Inc., 675 Mass
   Ave, Cambridge, MA 02139, USA.
   
   please send patches or advice on flash to: `flash@netsoc.ucd.ie'
   */

#include<stdio.h>
#include<stdlib.h>
#include<string.h>
#include<pwd.h>
#include<sys/types.h>
#include<sys/wait.h>
#include<sys/stat.h>
#include<fcntl.h>
#include<unistd.h>

#include"set.h"
#include"config.h"
#include"parseline.h"
#include"misc.h"

extern char *progname;

int parseline (char *buffer, int *argc, char **argv, int maxargc)
{
  enum parse_state state=S_LWSP,savedstate=0; 
  int remaining;
  char *here = buffer;
  char *storage, *addhere=NULL, *rememberme=NULL, *charpointer=NULL;
  char lastquote='\0';
  struct passwd *pwd;

  *argc = 0;

  storage = xmalloc ((strlen (buffer) + 265) * sizeof (char));
  *storage = '0';

  remaining = strlen (buffer);
  addhere = storage;

  while ((remaining) && (*argc < maxargc))
    {
      switch (state)
	{
	case S_LWSP:
	  switch (*here)
	    {
	    case ' ':
	    case '\t':
	    case '\n':
	      here++, remaining--;
	      break;
	    case '~':
/*            savedstate=state; */
	      rememberme = addhere;
	      state = S_TILDE;
	      *(addhere++) = *(here++);
	      remaining--;
	      break;
	    default:
	      state = S_WORD;
	      break;
	    }
	  break;
	case S_WORD:
	  switch (*here)
	    {
	    case ' ':
	    case '\t':
	    case '\n':
	      state = S_LWSP;
	      *addhere = '\0';
	      *(argv + *argc) =
		xmalloc ((strlen (storage) + 1) * sizeof (char));
	      strcpy (*(argv + *argc), storage);
	      addhere = storage;
	      (*argc)++;
	      here++, remaining--;
	      break;
	    case COMMENT:
	      here++,remaining=0;
	      break;
	    case ESCAPE:
	      savedstate = state;
	      state = S_ESCAPED;
	      here++, remaining--;
	      break;
	    case '"':
	    case '\'':
	      state = S_QUOTED;
	      lastquote = *(here++);
	      remaining--;
	      break;
	    case '$':
/*            savedstate=state; */
	      rememberme = addhere;
	      state = S_DOLLAR;
	      *(addhere++) = *(here++);
	      remaining--;
	      break;
	    default:
	      *(addhere++) = *(here++);
	      remaining--;
	      break;
	    }
	  break;
	case S_QUOTED:
	  if (*here == ESCAPE)
	    {
	      savedstate = state;
	      state = S_ESCAPED;
	      here++, remaining--;
	    }
	  else if (*here == lastquote)
	    {
	      state = S_WORD;
	      here++, remaining--;
	    }
	  else
	    {
	      *(addhere++) = *(here++);
	      remaining--;
	    }
	  break;
	case S_ESCAPED:
	  *(addhere++) = *(here++);
	  remaining--;
	  state = savedstate;
	  break;
	case S_TILDE:
	  switch (*here)
	    {
	    case ESCAPE:
	      savedstate = state;
	      state = S_ESCAPED;
	      here++, remaining--;
	      break;
	    case '/':
	    case ' ':
	    case '\t':
	    case '\n':
	      state = S_WORD;
	      *addhere = '\0';
	      if (addhere == rememberme + 1)
		pwd = getpwuid (getuid ());
	      else
		pwd = getpwnam (rememberme + 1);
	      if (pwd != NULL)
		{
		  strcpy (rememberme, pwd->pw_dir);
		  addhere = rememberme + strlen (rememberme);
		}
	      break;
	    case COMMENT:
	      here++,remaining=0;
	      break;
	    default:
	      *(addhere++) = *(here++);
	      remaining--;
	      break;
	    }
	  break;
	case S_DOLLAR:
	  switch (*here)
	    {
	    case ESCAPE:
	      savedstate = state;
	      state = S_ESCAPED;
	      here++, remaining--;
	      break;
	    case COMMENT:
	      here++,remaining=0;
	      break;
	    case '\'':
	    case '\"':
	    case ' ':
	    case '\t':
	    case '\n':
	      state = S_WORD;
	      *addhere = '\0';
	      if (addhere == rememberme + 1)
		charpointer = NULL;
	      else
		charpointer = getenv (rememberme + 1);
	      if (charpointer != NULL)
		{
		  strcpy (rememberme, charpointer);
		  addhere = rememberme + strlen (rememberme);
		}
	      break;
	    default:
	      *(addhere++) = *(here++);
	      remaining--;
	      break;
	    }
	  break;
	default:
	  fprintf (stderr, "Weirdness Factor 12\n");
	  return -1;
	  break;
	}
    }

  if (state == S_TILDE)
    {
      *addhere = '\0';
      if (addhere == (rememberme + 1))
	pwd = getpwuid (getuid ());
      else
	pwd = getpwnam (rememberme + 1);
      if (pwd != NULL)
	{
	  strcpy (rememberme, pwd->pw_dir);
	  addhere = rememberme + strlen (rememberme);
	}
    }
  else if (state == S_DOLLAR)
    {
      *addhere = '\0';
      if (addhere == rememberme + 1)
	charpointer = NULL;
      else
	charpointer = getenv (rememberme + 1);
      if (charpointer != NULL)
	{
	  strcpy (rememberme, charpointer);
	  addhere = rememberme + strlen (rememberme);
	}
    }

  *addhere = '\0';

  if ((*argc < maxargc) && (strlen (storage) != 0))
    {
      *(argv + *argc) = xmalloc ((strlen (storage) + 1) * sizeof (char));
      strcpy (*(argv + *argc), storage);
      addhere = storage;
      (*argc)++;
    }

  free ((void *) storage);
  return *argc;
}