ifrename.c

wireless tools: used to manipulate the Wireless Extensions. The Wireless Extensions is an interface

      if(slen == strlen(selector_list[i].name))
	return &selector_list[i];

      /* Partial match */
      if(found == NULL)
	/* First time */
	found = &selector_list[i];
      else
	/* Another time */
	if (selector_list[i].add_fn != found->add_fn)
	  ambig = 1;
    }

  if(found == NULL)
    {
      fprintf(stderr, "Error: Unknown selector `%.*s' at line %d.\n",
	      (int) slen, string, linenum);
      return NULL;
    }

  if(ambig)
    {
      fprintf(stderr, "Selector `%.*s'at line %d is ambiguous.\n",
	      (int) slen, string, linenum);
      return NULL;
    }

  return found;
}

/*------------------------------------------------------------------*/
/*
 * Read the configuration file and extract all valid mappings and their
 * selectors.
 */
static int
mapping_readfile(const char *	filename)
{
  FILE *		stream;
  char *		linebuf = NULL;
  size_t		linelen = 0; 
  int			linenum = 0; 
  struct add_extra	extrainfo;

  /* Reset the list of filters */
  bzero(selector_active, sizeof(selector_active));

  /* Check filename */
  if(!strcmp(filename, "-"))
    {
      /* Read from stdin */
      stream = stdin;

    }
  else
    {
      /* Open the file for reading */
      stream = fopen(filename, "r");
      if(!stream) 
	{
	  fprintf(stderr, "Error: Can't open configuration file `%s': %s\n",
		  filename, strerror(errno)); 
	  return(-1);
	}
    }

  /* Read each line of file
   * getline is a GNU extension :-( The buffer is recycled and increased
   * as needed by getline. */
  while(getline(&linebuf, &linelen, stream) > 0)
    {
      struct if_mapping *	ifnode;
      char *			p;
      char *			e;
      size_t			n;
      int			ret = -13;	/* Complain if no selectors */

      /* Keep track of line number */
      linenum++;

      /* Every comments terminates parsing */
      if((p = strchr(linebuf,'#')) != NULL)
	*p = '\0';

      /* Get interface name */
      p = linebuf;
      while(isspace(*p))
	++p; 
      if(*p == '\0')
	continue;	/* Line ended */
      n = strcspn(p, " \t\n");

      /* Create mapping */
      ifnode = mapping_create(p, n, linenum);
      if(!ifnode)
	continue;	/* Ignore this line */
      p += n;
      p += strspn(p, " \t\n"); 

      /* Loop on all selectors */
      while(*p != '\0')
	{
	  const struct mapping_selector *	selector = NULL;
	  struct add_extra *			extra = NULL;

	  /* Selector name length - stop at modifier start */
	  n = strcspn(p, " \t\n{");

	  /* Find it */
	  selector = selector_find(p, n, linenum);
	  if(!selector)
	    {
	      ret = -1;
	      break;
	    }
	  p += n;

	  /* Check for modifier */
	  if(*p == '{')
	    {
	      p++;
	      /* Find end of modifier */
	      e = strchr(p, '}');
	      if(e == NULL)
		{
		  fprintf(stderr,
			  "Error: unterminated selector modifier value on line %d\n",
			  linenum);
		  ret = -1;
		  break;	/* Line ended */
		}
	      /* Fill in struct and hook it */
	      extrainfo.modif_pos = p;
	      extrainfo.modif_len = e - p;
	      extra = &extrainfo;
	      /* Terminate modifier value */
	      e[0] = '\0';
	      /* Skip it */
	      p = e + 1;
	    }

	  /* Get to selector value */
	  p += strspn(p, " \t\n"); 
	  if(*p == '\0')
	    {
	      fprintf(stderr, "Error: no value for selector `%s' on line %d\n",
		      selector->name, linenum);
	      ret = -1;
	      break;	/* Line ended */
	    }
	  /* Check for quoted arguments */
	  if(*p == '"')
	    {
	      p++;
	      e = strchr(p, '"');
	      if(e == NULL)
		{
		  fprintf(stderr,
			  "Error: unterminated quoted value on line %d\n",
			  linenum);
		  ret = -1;
		  break;	/* Line ended */
		}
	      n = e - p;
	      e++;
	    }
	  else
	    {
	      /* Just end at next blank */
	      n = strcspn(p, " \t\n");
	      e = p + n;
	    }
	  /* Make 'e' point past the '\0' we are going to add */
	  if(*e != '\0')
	    e++;
	  /* Terminate selector value */
	  p[n] = '\0';

	  /* Add it to the mapping */
	  ret = selector->add_fn(ifnode, selector_active, p, n,
				 extra, linenum);
	  if(ret < 0)
	    break;

	  /* Go to next selector */
	  p = e;
	  p += strspn(p, " \t\n"); 
	}

      /* We add a mapping only if it has at least one selector and if all
       * selectors were parsed properly. */
      if(ret < 0)
	{
	  /* If we have not yet printed an error, now is a good time ;-) */
	  if(ret == -13)
	    fprintf(stderr, "Error: Line %d ignored, no valid selectors\n",
		    linenum);
	  else
	    fprintf(stderr, "Error: Line %d ignored due to prior errors\n",
		    linenum);

	  free(ifnode);
	}
      else
	{
	  /* Link it in the list */
	  ifnode->next = mapping_list;
	  mapping_list = ifnode;
	}
    }

  /* Cleanup */
  free(linebuf);

  /* Finished reading, close the file */
  if(stream != stdin)
    fclose(stream);
  return(0);
}

/*------------------------------------------------------------------*/
/*
 * Extract all the interesting selectors for the interface in consideration
 */
static struct if_mapping *
mapping_extract(int		skfd,
		const char *	ifname)
{
  struct if_mapping *	target;
  int			i;

  /* Create mapping, zero it */
  target = calloc(1, sizeof(if_mapping));
  if(!target)
    {
      fprintf(stderr, "Error: Can't allocate interface mapping.\n");  
      return(NULL);
    }

  /* Set the interface name */
  strcpy(target->ifname, ifname);

  /* Loop on all active selectors */
  for(i = 0; i < SELECT_NUM; i++)
    {
      /* Check if this selector is active */
      if(selector_active[i] != 0)
	{
	  /* Extract selector */
	  selector_list[i].get_fn(skfd, ifname, target, selector_active[i]);

	  /* Ignore errors. Some mapping may not need all selectors */
	}
    }

  return(target);
} 

/*------------------------------------------------------------------*/
/*
 * Find the first mapping in the list matching the one we want.
 */
static struct if_mapping *
mapping_find(struct if_mapping *	target)
{
  struct if_mapping *	ifnode;
  int			i;

  /* Look over all our mappings */
  for(ifnode = mapping_list; ifnode != NULL; ifnode = ifnode->next)
    {
      int		matches = 1;

      /* Look over all our selectors, all must match */
      for(i = 0; i < SELECT_NUM; i++)
	{
	  /* Check if this selector is active */
	  if(ifnode->active[i] != 0)
	    {
	      /* If this selector doesn't match, game over for this mapping */
	      if((target->active[i] == 0) ||
		 (selector_list[i].cmp_fn(ifnode, target) != 0))
		{
		  matches = 0;
		  break;
		}
	    }
	}

      /* Check is this mapping was "the one" */
      if(matches)
	return(ifnode);
    }

  /* Not found */
  return(NULL);
} 

/************************** MODULE SUPPORT **************************/
/*
 * Load all necessary module so that interfaces do exist.
 * This is necessary for system that are fully modular when
 * doing the boot time processing, because we need to run before
 * 'ifup -a'.
 */

/*------------------------------------------------------------------*/
/*
 * Probe interfaces based on our list of mappings.
 * This is the default, but usually not the best way to do it.
 */
static void
probe_mappings(int		skfd)
{
  struct if_mapping *	ifnode;
  struct ifreq		ifr;

  /* Look over all our mappings */
  for(ifnode = mapping_list; ifnode != NULL; ifnode = ifnode->next)
    {
      /* Can't load wildcards interface name :-( */
      if(strchr(ifnode->ifname, '%') != NULL)
	continue;

      if(verbose)
	fprintf(stderr, "Probing : Trying to load interface [%s]\n",
		ifnode->ifname);

      /* Trick the kernel into loading the interface.
       * This allow us to not depend on the exact path and
       * name of the '/sbin/modprobe' command.
       * Obviously, we expect this command to 'fail', as
       * the interface will load with the old/wrong name.
       */
      strncpy(ifr.ifr_name, ifnode->ifname, IFNAMSIZ);
      ioctl(skfd, SIOCGIFHWADDR, &ifr);
    }
}

/*------------------------------------------------------------------*/
/*
 * Probe interfaces based on Debian's config files.
 * This allow to enly load modules for interfaces the user want active,
 * all built-in interfaces that should remain unconfigured won't
 * be probed (and can have mappings).
 */
static void
probe_debian(int		skfd)
{
  FILE *		stream;
  char *		linebuf = NULL;
  size_t		linelen = 0; 
  struct ifreq		ifr;

  /* Open Debian config file */
  stream = fopen(DEBIAN_CONFIG_FILE, "r");
  if(stream == NULL)
    {
      fprintf(stderr, "Error: can't open file [%s]\n", DEBIAN_CONFIG_FILE);
      return;
    }

  /* Read each line of file
   * getline is a GNU extension :-( The buffer is recycled and increased
   * as needed by getline. */
  while(getline(&linebuf, &linelen, stream) > 0)
    {
      char *			p;
      char *			e;
      size_t			n;

      /* Check for auto keyword, ignore when commented out */
      if(!strncasecmp(linebuf, "auto ", 5))
	{
	  /* Skip "auto" keyword */
	  p = linebuf + 5;

	  /* Terminate at first comment */
	  e = strchr(p, '#');
	  if(e != NULL)
	    *e = '\0';

	  /* Loop on all interfaces given */
	  while(*p != '\0')
	    {
	      /* Interface name length */
	      n = strcspn(p, " \t\n");

	      /* Look for end of interface name */
	      e = p + n;
	      /* Make 'e' point past the '\0' we are going to add */
	      if(*e != '\0')
		e++;
	      /* Terminate interface name */
	      p[n] = '\0';

	      if(verbose)
		fprintf(stderr, "Probing : Trying to load interface [%s]\n",
			p);

	      /* Load interface */
	      strncpy(ifr.ifr_name, p, IFNAMSIZ);
	      ioctl(skfd, SIOCGIFHWADDR, &ifr);

	      /* Go to next interface name */
	      p = e;
	      p += strspn(p, " \t\n"); 
	    }
	}
    }

  /* Done */
  fclose(stream);
  return;
}

/**************************** MAIN LOGIC ****************************/

/*------------------------------------------------------------------*/
/*
 * Rename an interface to a specified new name.
 */
static int
process_rename(int	skfd,
	       char *	ifname,
	       char *	newname)
{
  char		retname[IFNAMSIZ+1];
  int		len;
  char *	star;

  len = strlen(newname);
  star = strchr(newname, '*');

  /* Check newname length, need one extra char for wildcard */
  if((len + (star != NULL)) > IFNAMSIZ)
    {
      fprintf(stderr, "Error: Interface name `%s' too long.\n",
	      newname);  
      return(-1);
    }

  /* Change the name of the interface */
  if(if_set_name(skfd, ifname, newname, retname) < 0)
    {
      fprintf(stderr, "Error: cannot change name of %s to %s: %s\n",
	      ifname, newname, strerror(errno)); 
      return(-1);
    }

  /* Always print out the *new* interface name so that
   * the calling script can pick it up and know where its interface
   * has gone. */
  printf("%s\n", retname);

  /* Done */
  return(0);
}

/*------------------------------------------------------------------*/
/*
 * Process a specified interface.
 */
static int
process_ifname(int	skfd,
	       char *	ifname,
	       char *	args[],
	       int	count)
{
  struct if_mapping *		target;
  const struct if_mapping *	mapping;
  char				retname[IFNAMSIZ+1];

  /* Avoid "Unused parameter" warning */
  args = args; count = count;

  /* Get description of this interface */
  target = mapping_extract(skfd, ifname);
  if(target == NULL)
    return(-1);

  /* If udev is calling us, get the real devpath. */
  if(udev_output)
    {
      const char *env;
      /* It's passed to us as an environment variable */
      env = getenv("DEVPATH");
      if(env)
	{
	  int	env_len = strlen(env);
	  target->sysfs_devplen = env_len;
	  /* Make enough space for new interface name */
	  target->sysfs_devpath = malloc(env_len + IFNAMSIZ + 1);
	  if(target->sysfs_devpath != NULL)
	    memcpy(target->sysfs_devpath, env, env_len + 1);
	}
      /* We will get a second chance is the user has some sysfs selectors */
    }

  /* Find matching mapping */