Move the core of the lib/config/config.c functionality into libdevmapper,

leaving behind the LVM-specific parts of the code (convenience wrappers that
handle `struct device` and `struct cmd_context`, basically). A number of
functions have been renamed (in addition to getting a dm_ prefix) -- namely,
all of the config interface now has a dm_config_ prefix.

libdm/libdm-string.c

@@ -161,3 +161,225 @@ int dm_asprintf(char **result, const char *format, ...)
 	dm_free(buf);
 	return n + 1;
 }
+
+/*
+ * Count occurences of 'c' in 'str' until we reach a null char.
+ *
+ * Returns:
+ *  len - incremented for each char we encounter.
+ *  count - number of occurrences of 'c' and 'c2'.
+ */
+static void _count_chars(const char *str, size_t *len, int *count,
+			 const int c1, const int c2)
+{
+	const char *ptr;
+
+	for (ptr = str; *ptr; ptr++, (*len)++)
+		if (*ptr == c1 || *ptr == c2)
+			(*count)++;
+}
+
+unsigned dm_count_chars(const char *str, size_t len, const int c)
+{
+	size_t i;
+	unsigned count = 0;
+
+	for (i = 0; i < len; i++)
+		if (str[i] == c)
+			count++;
+
+	return count;
+}
+
+size_t dm_escaped_len(const char *str)
+{
+	size_t len = 1;
+	int count = 0;
+
+	_count_chars(str, &len, &count, '\"', '\\');
+
+	return count + len;
+}
+
+/*
+ * Copies a string, quoting orig_char with quote_char.
+ * Optionally also quote quote_char.
+ */
+static void _quote_characters(char **out, const char *src,
+			      const int orig_char, const int quote_char,
+			      int quote_quote_char)
+{
+	while (*src) {
+		if (*src == orig_char ||
+		    (*src == quote_char && quote_quote_char))
+			*(*out)++ = quote_char;
+
+		*(*out)++ = *src++;
+	}
+}
+
+static void _unquote_one_character(char *src, const char orig_char,
+				   const char quote_char)
+{
+	char *out;
+	char s, n;
+
+	/* Optimise for the common case where no changes are needed. */
+	while ((s = *src++)) {
+		if (s == quote_char &&
+		    ((n = *src) == orig_char || n == quote_char)) {
+			out = src++;
+			*(out - 1) = n;
+
+			while ((s = *src++)) {
+				if (s == quote_char &&
+				    ((n = *src) == orig_char || n == quote_char)) {
+					s = n;
+					src++;
+				}
+				*out = s;
+				out++;
+			}
+
+			*out = '\0';
+			return;
+		}
+	}
+}
+
+/*
+ * Unquote each character given in orig_char array and unquote quote_char
+ * as well. Also save the first occurrence of each character from orig_char
+ * that was found unquoted in arr_substr_first_unquoted array. This way we can
+ * process several characters in one go.
+ */
+static void _unquote_characters(char *src, const char *orig_chars,
+				size_t num_orig_chars,
+				const char quote_char,
+				char *arr_substr_first_unquoted[])
+{
+	char *out = src;
+	char c, s, n;
+	unsigned i;
+
+	while ((s = *src++)) {
+		for (i = 0; i < num_orig_chars; i++) {
+			c = orig_chars[i];
+			if (s == quote_char &&
+			    ((n = *src) == c || n == quote_char)) {
+				s = n;
+				src++;
+				break;
+			}
+			if (arr_substr_first_unquoted && (s == c) &&
+			    !arr_substr_first_unquoted[i])
+				arr_substr_first_unquoted[i] = out;
+		};
+		*out++ = s;
+	}
+
+	*out = '\0';
+}
+
+/*
+ * Copies a string, quoting hyphens with hyphens.
+ */
+static void _quote_hyphens(char **out, const char *src)
+{
+	_quote_characters(out, src, '-', '-', 0);
+}
+
+char *dm_build_dm_name(struct dm_pool *mem, const char *vgname,
+		       const char *lvname, const char *layer)
+{
+	size_t len = 1;
+	int hyphens = 1;
+	char *r, *out;
+
+	_count_chars(vgname, &len, &hyphens, '-', 0);
+	_count_chars(lvname, &len, &hyphens, '-', 0);
+
+	if (layer && *layer) {
+		_count_chars(layer, &len, &hyphens, '-', 0);
+		hyphens++;
+	}
+
+	len += hyphens;
+
+	if (!(r = dm_pool_alloc(mem, len))) {
+		log_error("build_dm_name: Allocation failed for %" PRIsize_t
+			  " for %s %s %s.", len, vgname, lvname, layer);
+		return NULL;
+	}
+
+	out = r;
+	_quote_hyphens(&out, vgname);
+	*out++ = '-';
+	_quote_hyphens(&out, lvname);
+
+	if (layer && *layer) {
+		/* No hyphen if the layer begins with _ e.g. _mlog */
+		if (*layer != '_')
+			*out++ = '-';
+		_quote_hyphens(&out, layer);
+	}
+	*out = '\0';
+
+	return r;
+}
+
+char *dm_build_dm_uuid(struct dm_pool *mem, const char *prefix, const char *lvid, const char *layer)
+{
+	char *dmuuid;
+	size_t len;
+
+	if (!layer)
+		layer = "";
+
+	len = strlen(prefix) + strlen(lvid) + strlen(layer) + 1;
+
+	if (!(dmuuid = dm_pool_alloc(mem, len))) {
+		log_error("build_dm_name: Allocation failed for %" PRIsize_t
+			  " %s %s.", len, lvid, layer);
+		return NULL;
+	}
+
+	sprintf(dmuuid, "%s%s%s%s", prefix, lvid, (*layer) ? "-" : "", layer);
+
+	return dmuuid;
+}
+
+/*
+ * Copies a string, quoting double quotes with backslashes.
+ */
+char *dm_escape_double_quotes(char *out, const char *src)
+{
+	char *buf = out;
+
+	_quote_characters(&buf, src, '\"', '\\', 1);
+	*buf = '\0';
+
+	return out;
+}
+
+void dm_unescape_double_quotes(char *src)
+{
+	_unquote_one_character(src, '\"', '\\');
+}
+
+void dm_unescape_colons_and_at_signs(char *src,
+				     char **substr_first_unquoted_colon,
+				     char **substr_first_unquoted_at_sign)
+{
+	const char *orig_chars = ":@";
+	char *arr_substr_first_unquoted[] = {NULL, NULL, NULL};
+
+	_unquote_characters(src, orig_chars, 2, '\\', arr_substr_first_unquoted);
+
+	if (substr_first_unquoted_colon)
+		*substr_first_unquoted_colon = arr_substr_first_unquoted[0];
+
+	if (substr_first_unquoted_at_sign)
+		*substr_first_unquoted_at_sign = arr_substr_first_unquoted[1];
+}
+