pvfs_shortname.c

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	} else {
		extension[0] = 0;
	}

	if (extension[0]) {
		return talloc_asprintf(mem_ctx, "%s.%s", prefix, extension);
	}

	return talloc_strdup(mem_ctx, prefix);
}


/*
  look for a DOS reserved name
*/
static bool is_reserved_name(struct pvfs_mangle_context *ctx, const char *name)
{
	if (FLAG_CHECK(name[0], FLAG_POSSIBLE1) &&
	    FLAG_CHECK(name[1], FLAG_POSSIBLE2) &&
	    FLAG_CHECK(name[2], FLAG_POSSIBLE3) &&
	    FLAG_CHECK(name[3], FLAG_POSSIBLE4)) {
		/* a likely match, scan the lot */
		int i;
		for (i=0; reserved_names[i]; i++) {
			if (strcasecmp(name, reserved_names[i]) == 0) {
				return true;
			}
		}
	}

	return false;
}


/*
 See if a filename is a legal long filename.
 A filename ending in a '.' is not legal unless it's "." or "..". JRA.
*/
static bool is_legal_name(struct pvfs_mangle_context *ctx, const char *name)
{
	while (*name) {
		size_t c_size;
		codepoint_t c = next_codepoint(ctx->iconv_convenience, name, &c_size);
		if (c == INVALID_CODEPOINT) {
			return false;
		}
		/* all high chars are OK */
		if (c >= 128) {
			name += c_size;
			continue;
		}
		if (FLAG_CHECK(c, FLAG_ILLEGAL)) {
			return false;
		}
		name += c_size;
	}

	return true;
}

/*
  the main forward mapping function, which converts a long filename to 
  a 8.3 name

  if need83 is not set then we only do the mangling if the name is illegal
  as a long name

  if cache83 is not set then we don't cache the result

  return NULL if we don't need to do any conversion
*/
static char *name_map(struct pvfs_mangle_context *ctx,
		      const char *name, bool need83, bool cache83)
{
	char *dot_p;
	char lead_chars[7];
	char extension[4];
	unsigned int extension_length, i;
	unsigned int prefix_len;
	uint32_t hash, v;
	char *new_name;
	const char *basechars = MANGLE_BASECHARS;

	/* reserved names are handled specially */
	if (!is_reserved_name(ctx, name)) {
		/* if the name is already a valid 8.3 name then we don't need to 
		   do anything */
		if (is_8_3(ctx, name, false, false)) {
			return NULL;
		}

		/* if the caller doesn't strictly need 8.3 then just check for illegal 
		   filenames */
		if (!need83 && is_legal_name(ctx, name)) {
			return NULL;
		}
	}

	/* find the '.' if any */
	dot_p = strrchr(name, '.');

	if (dot_p) {
		/* if the extension contains any illegal characters or
		   is too long or zero length then we treat it as part
		   of the prefix */
		for (i=0; i<4 && dot_p[i+1]; i++) {
			if (! FLAG_CHECK(dot_p[i+1], FLAG_ASCII)) {
				dot_p = NULL;
				break;
			}
		}
		if (i == 0 || i == 4) dot_p = NULL;
	}

	/* the leading characters in the mangled name is taken from
	   the first characters of the name, if they are ascii otherwise
	   '_' is used
	*/
	for (i=0;i<ctx->mangle_prefix && name[i];i++) {
		lead_chars[i] = name[i];
		if (! FLAG_CHECK(lead_chars[i], FLAG_ASCII)) {
			lead_chars[i] = '_';
		}
		lead_chars[i] = toupper((unsigned char)lead_chars[i]);
	}
	for (;i<ctx->mangle_prefix;i++) {
		lead_chars[i] = '_';
	}

	/* the prefix is anything up to the first dot */
	if (dot_p) {
		prefix_len = PTR_DIFF(dot_p, name);
	} else {
		prefix_len = strlen(name);
	}

	/* the extension of the mangled name is taken from the first 3
	   ascii chars after the dot */
	extension_length = 0;
	if (dot_p) {
		for (i=1; extension_length < 3 && dot_p[i]; i++) {
			unsigned char c = dot_p[i];
			if (FLAG_CHECK(c, FLAG_ASCII)) {
				extension[extension_length++] = toupper(c);
			}
		}
	}
	   
	/* find the hash for this prefix */
	v = hash = mangle_hash(ctx, name, prefix_len);

	new_name = talloc_array(ctx, char, 13);
	if (new_name == NULL) {
		return NULL;
	}

	/* now form the mangled name. */
	for (i=0;i<ctx->mangle_prefix;i++) {
		new_name[i] = lead_chars[i];
	}
	new_name[7] = basechars[v % 36];
	new_name[6] = '~';	
	for (i=5; i>=ctx->mangle_prefix; i--) {
		v = v / 36;
		new_name[i] = basechars[v % 36];
	}

	/* add the extension */
	if (extension_length) {
		new_name[8] = '.';
		memcpy(&new_name[9], extension, extension_length);
		new_name[9+extension_length] = 0;
	} else {
		new_name[8] = 0;
	}

	if (cache83) {
		/* put it in the cache */
		cache_insert(ctx, name, prefix_len, hash);
	}

	M_DEBUG(10,("name_map: %s -> %08X -> %s (cache=%d)\n", 
		   name, hash, new_name, cache83));

	return new_name;
}


/* initialise the flags table 

  we allow only a very restricted set of characters as 'ascii' in this
  mangling backend. This isn't a significant problem as modern clients
  use the 'long' filenames anyway, and those don't have these
  restrictions. 
*/
static void init_tables(struct pvfs_mangle_context *ctx)
{
	const char *basechars = MANGLE_BASECHARS;
	int i;
	/* the list of reserved dos names - all of these are illegal */

	ZERO_STRUCT(ctx->char_flags);

	for (i=1;i<128;i++) {
		if ((i >= '0' && i <= '9') || 
		    (i >= 'a' && i <= 'z') || 
		    (i >= 'A' && i <= 'Z')) {
			ctx->char_flags[i] |=  (FLAG_ASCII | FLAG_BASECHAR);
		}
		if (strchr("_-$~", i)) {
			ctx->char_flags[i] |= FLAG_ASCII;
		}

		if (strchr("*\\/?<>|\":", i)) {
			ctx->char_flags[i] |= FLAG_ILLEGAL;
		}

		if (strchr("*?\"<>", i)) {
			ctx->char_flags[i] |= FLAG_WILDCARD;
		}
	}

	ZERO_STRUCT(ctx->base_reverse);
	for (i=0;i<36;i++) {
		ctx->base_reverse[(uint8_t)basechars[i]] = i;
	}	

	/* fill in the reserved names flags. These are used as a very
	   fast filter for finding possible DOS reserved filenames */
	for (i=0; reserved_names[i]; i++) {
		unsigned char c1, c2, c3, c4;

		c1 = (unsigned char)reserved_names[i][0];
		c2 = (unsigned char)reserved_names[i][1];
		c3 = (unsigned char)reserved_names[i][2];
		c4 = (unsigned char)reserved_names[i][3];

		ctx->char_flags[c1] |= FLAG_POSSIBLE1;
		ctx->char_flags[c2] |= FLAG_POSSIBLE2;
		ctx->char_flags[c3] |= FLAG_POSSIBLE3;
		ctx->char_flags[c4] |= FLAG_POSSIBLE4;
		ctx->char_flags[tolower(c1)] |= FLAG_POSSIBLE1;
		ctx->char_flags[tolower(c2)] |= FLAG_POSSIBLE2;
		ctx->char_flags[tolower(c3)] |= FLAG_POSSIBLE3;
		ctx->char_flags[tolower(c4)] |= FLAG_POSSIBLE4;

		ctx->char_flags[(unsigned char)'.'] |= FLAG_POSSIBLE4;
	}

	ctx->mangle_modulus = 1;
	for (i=0;i<(7-ctx->mangle_prefix);i++) {
		ctx->mangle_modulus *= 36;
	}
}

/* 
   initialise the mangling code 
 */
NTSTATUS pvfs_mangle_init(struct pvfs_state *pvfs)
{
	struct pvfs_mangle_context *ctx;

	ctx = talloc(pvfs, struct pvfs_mangle_context);
	if (ctx == NULL) {
		return NT_STATUS_NO_MEMORY;
	}

	ctx->iconv_convenience = lp_iconv_convenience(pvfs->ntvfs->ctx->lp_ctx);

	/* by default have a max of 512 entries in the cache. */
	ctx->cache_size = lp_parm_int(pvfs->ntvfs->ctx->lp_ctx, NULL, "mangle", "cachesize", 512);

	ctx->prefix_cache = talloc_array(ctx, char *, ctx->cache_size);
	if (ctx->prefix_cache == NULL) {
		return NT_STATUS_NO_MEMORY;
	}
	ctx->prefix_cache_hashes = talloc_array(ctx, uint32_t, ctx->cache_size);
	if (ctx->prefix_cache_hashes == NULL) {
		return NT_STATUS_NO_MEMORY;
	}

	memset(ctx->prefix_cache, 0, sizeof(char *) * ctx->cache_size);
	memset(ctx->prefix_cache_hashes, 0, sizeof(uint32_t) * ctx->cache_size);

	ctx->mangle_prefix = lp_parm_int(pvfs->ntvfs->ctx->lp_ctx, NULL, "mangle", "prefix", -1);
	if (ctx->mangle_prefix < 0 || ctx->mangle_prefix > 6) {
		ctx->mangle_prefix = DEFAULT_MANGLE_PREFIX;
	}

	init_tables(ctx);

	pvfs->mangle_ctx = ctx;

	return NT_STATUS_OK;
}


/*
  return the short name for a component of a full name
*/
char *pvfs_short_name_component(struct pvfs_state *pvfs, const char *name)
{
	return name_map(pvfs->mangle_ctx, name, true, true);
}


/*
  return the short name for a given entry in a directory
*/
const char *pvfs_short_name(struct pvfs_state *pvfs, TALLOC_CTX *mem_ctx, 
			    struct pvfs_filename *name)
{
	char *p = strrchr(name->full_name, '/');
	char *ret = pvfs_short_name_component(pvfs, p+1);
	if (ret == NULL) {
		return p+1;
	}
	talloc_steal(mem_ctx, ret);
	return ret;
}

/*
  lookup a mangled name, returning the original long name if present
  in the cache
*/
char *pvfs_mangled_lookup(struct pvfs_state *pvfs, TALLOC_CTX *mem_ctx, 
			  const char *name)
{
	return check_cache(pvfs->mangle_ctx, mem_ctx, name);
}


/*
  look for a DOS reserved name
*/
bool pvfs_is_reserved_name(struct pvfs_state *pvfs, const char *name)
{
	return is_reserved_name(pvfs->mangle_ctx, name);
}


/*
  see if a component of a filename could be a mangled name from our
  mangling code
*/
bool pvfs_is_mangled_component(struct pvfs_state *pvfs, const char *name)
{
	return is_mangled_component(pvfs->mangle_ctx, name, strlen(name));
}