/* netrc.c -- parse the .netrc file to get hosts, accounts, and passwords

   Gordon Matzigkeit <gord@gnu.ai.mit.edu>, 1996

   For license terms, see the file COPYING in this directory.

   Compile with -DSTANDALONE to test this module. */

#include <stdio.h>
#include <ctype.h>
#include <stdlib.h>
#include <string.h>

#include "netrc.h"

#define BUFSIZE 2048

#ifndef _
# define _(x) (x)
#endif

/* Normally defined in xstrdup.c. */
#ifndef xstrdup
# define xstrdup strdup
#endif

/* Normally defined in xmalloc.c */
#ifndef xmalloc
# define xmalloc malloc
#endif
#ifndef xrealloc
# define xrealloc realloc
#endif

# ifdef STANDALONE
char *program_name = "netrc";
#endif

/* Maybe add NEWENTRY to the account information list, LIST.  NEWENTRY is
   set to a ready-to-use netrc_entry, in any event. */
static void
maybe_add_to_list (netrc_entry ** newentry, netrc_entry ** list)
{
  netrc_entry *a, *l;
  a = *newentry;
  l = *list;

  /* We need an account name in order to add the entry to the list. */
  if (a && !a->account)
    {
      /* Free any allocated space. */
      if (a->host)
	free (a->host);
      if (a->password)
	free (a->password);
    }
  else
    {
      if (a)
	{
	  /* Add the current machine into our list. */
	  a->next = l;
	  l = a;
	}

      /* Allocate a new netrc_entry structure. */
      a = (netrc_entry *) xmalloc (sizeof (netrc_entry));
    }

  /* Zero the structure, so that it is ready to use. */
  memset (a, 0, sizeof (*a));

  /* Return the new pointers. */
  *newentry = a;
  *list = l;
  return;
}


/* Parse FILE as a .netrc file (as described in ftp(1)), and return a
   list of entries.  NULL is returned if the file could not be
   parsed. */
netrc_entry *
parse_netrc (file)
     char *file;
{
  FILE *fp;
  char buf[BUFSIZE + 1], *p, *tok;
  const char *premature_token;
  netrc_entry *current, *retval;
  int ln;

  /* The latest token we've seen in the file. */
  enum
  {
    tok_nothing, tok_account, tok_login, tok_macdef, tok_machine, tok_password
  }
  last_token = tok_nothing;

  current = retval = NULL;

  fp = fopen (file, "r");
  if (!fp)
    {
      /* Just return NULL if we can't open the file. */
      return NULL;
    }

  /* Initialize the file data. */
  ln = 0;
  premature_token = NULL;

  /* While there are lines in the file... */
  while (fgets (buf, BUFSIZE, fp))
    {
      ln++;

      /* Strip trailing CRLF */
      for (p = buf + strlen (buf) - 1; (p >= buf) && isspace (*p); p--)
	*p = '\0';

      /* Parse the line. */
      p = buf;

      /* If the line is empty... */
      if (!*p)
	{
	  if (last_token == tok_macdef)	/* end of macro */
	    last_token = tok_nothing;
	  else
	    continue;		/* otherwise ignore it */
	}

      /* If we are defining macros, then skip parsing the line. */
      while (*p && last_token != tok_macdef)
	{
	  char quote_char = 0;
	  char *pp;

	  /* Skip any whitespace. */
	  while (*p && isspace (*p))
	    p++;

	  /* Discard end-of-line comments. */
	  if (*p == '#')
	    break;

	  tok = pp = p;

	  /* Find the end of the token. */
	  while (*p && (quote_char || !isspace (*p)))
	    {
	      if (quote_char)
		{
		  if (quote_char == *p)
		    {
		      quote_char = 0;
		      p++;
		    }
		  else
		    {
		      *pp = *p;
		      p++;
		      pp++;
		    }
		}
	      else
		{
		  if (*p == '"' || *p == '\'')
		    quote_char = *p;
		  else
		    {
		      *pp = *p;
		      pp++;
		    }
		  p++;
		}
	    }
	  /* Null-terminate the token, if it isn't already. */
	  if (*p)
	    *p++ = '\0';
	  *pp = 0;

	  switch (last_token)
	    {
	    case tok_login:
	      if (current)
		current->account = (char *) xstrdup (tok);
	      else
		premature_token = "login";
	      break;

	    case tok_machine:
	      /* Start a new machine entry. */
	      maybe_add_to_list (&current, &retval);
	      current->host = (char *) xstrdup (tok);
	      break;

	    case tok_password:
	      if (current)
		current->password = (char *) xstrdup (tok);
	      else
		premature_token = "password";
	      break;

	      /* We handle most of tok_macdef above. */
	    case tok_macdef:
	      if (!current)
		premature_token = "macdef";
	      break;

	      /* We don't handle the account keyword at all. */
	    case tok_account:
	      if (!current)
		premature_token = "account";
	      break;

	      /* We handle tok_nothing below this switch. */
	    case tok_nothing:
	      break;
	    }

	  if (premature_token)
	    {
#ifdef HAVE_ERROR
	      error_at_line (0, file, ln,
			     _("warning: found \"%s\" before any host names"),
			     premature_token);
#else
	      fprintf (stderr,
		       _
		       ("mailcheck: %s:%d: warning: found \"%s\" before any host names\n"),
		       file, ln, premature_token);
#endif
	      premature_token = NULL;
	    }

	  if (last_token != tok_nothing)
	    /* We got a value, so reset the token state. */
	    last_token = tok_nothing;
	  else
	    {
	      /* Fetch the next token. */
	      if (!strcmp (tok, "default"))
		{
		  maybe_add_to_list (&current, &retval);
		}
	      else if (!strcmp (tok, "login"))
		last_token = tok_login;

	      else if (!strcmp (tok, "user"))
		last_token = tok_login;

	      else if (!strcmp (tok, "macdef"))
		last_token = tok_macdef;

	      else if (!strcmp (tok, "machine"))
		last_token = tok_machine;

	      else if (!strcmp (tok, "password"))
		last_token = tok_password;

	      else if (!strcmp (tok, "passwd"))
		last_token = tok_password;

	      else if (!strcmp (tok, "account"))
		last_token = tok_account;

	      else
		{
		  fprintf (stderr,
			   _("mailcheck: %s:%d: warning: unknown token \"%s\"\n"), file,
			   ln, tok);
		}
	    }
	}
    }

  fclose (fp);

  /* Finalize the last machine entry we found. */
  maybe_add_to_list (&current, &retval);
  free (current);

  /* Reverse the order of the list so that it appears in file order. */
  current = retval;
  retval = NULL;
  while (current)
    {
      netrc_entry *saved_reference;

      /* Change the direction of the pointers. */
      saved_reference = current->next;
      current->next = retval;

      /* Advance to the next node. */
      retval = current;
      current = saved_reference;
    }

  return retval;
}


/* Return the netrc entry from LIST corresponding to HOST.  NULL is
   returned if no such entry exists. */
netrc_entry *
search_netrc (list, host, account)
     netrc_entry *list;
     char *host, *account;
{
  /* Look for the HOST in LIST. */
  while (list)
    {
      if (list->host && !strcmp (list->host, host))
	if (!list->account || !strcmp (list->account, account))
	  /* We found a matching entry. */
	  break;

      list = list->next;
    }

  /* Return the matching entry, or NULL. */
  return list;
}


#ifdef STANDALONE
#include <sys/types.h>
#include <sys/stat.h>

extern int errno;

int
main (argc, argv)
     int argc;
     char **argv;
{
  struct stat sb;
  char *program_name, *file, *host, *account;
  netrc_entry *head, *a;

  program_name = argv[0];
  file = argv[1];
  host = argv[2];
  account = argv[3];

  if (stat (file, &sb))
    {
      fprintf (stderr, "%s: cannot stat %s: %s\n", argv[0], file,
	       strerror (errno));
      exit (1);
    }

  head = parse_netrc (file);
  if (!head)
    {
      fprintf (stderr, "%s: no entries found in %s\n", argv[0], file);
      exit (1);
    }

  if (host && account)
    {
      int i, status;
      status = 0;

      printf ("Host: %s, Account: %s\n", host, account);

      a = search_netrc (head, host, account);
      if (a)
	{
	  /* Print out the password (if any). */
	  if (a->password)
	    {
	      fputc (' ', stdout);
	      fputs (a->password, stdout);
	    }
	}
      fputc ('\n', stdout);

      exit (status);
    }

  /* Print out the entire contents of the netrc. */
  a = head;
  while (a)
    {
      /* Print the host name. */
      if (a->host)
	fputs (a->host, stdout);
      else
	fputs ("DEFAULT", stdout);

      fputc (' ', stdout);

      /* Print the account name. */
      fputs (a->account, stdout);

      if (a->password)
	{
	  /* Print the password, if there is any. */
	  fputc (' ', stdout);
	  fputs (a->password, stdout);
	}

      fputc ('\n', stdout);
      a = a->next;
    }

  exit (0);
}
#endif /* STANDALONE */
