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netrc.c

/* 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 */

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