Implement quote escaping. String values may now contain " if you

it is preceded by \.

foo="I \"like\" C++"

gives the value 'I "like" C++' to the variable 'foo'. If a character
other than " follows the \, both the \ and that character are passed
through.

Differential Revision: https://reviews.freebsd.org/D6286
Sponsored by: Netflix

1 files changed, 33 insertions, 2 deletions

diff --git a/sbin/devd/devd.cc b/sbin/devd/devd.cc
index baeb472a96f6..d37f0ee66c9e 100644
--- a/sbin/devd/devd.cc
+++ b/sbin/devd/devd.cc
@@ -411,6 +411,32 @@ var_list::is_set(const string &var) const
 	return (_vars.find(var) != _vars.end());
 }
 
+/** fix_value
+ *
+ * Removes quoted characters that have made it this far. \" are
+ * converted to ". For all other characters, both \ and following
+ * character. So the string 'fre\:\"' is translated to 'fred\:"'.
+ */
+const std::string &
+var_list::fix_value(const std::string &val) const
+{
+	char *tmp, *dst;
+	const char *src;
+	std::string *rv;
+
+	dst = tmp = new char[val.length()];
+	src = val.c_str();
+	while (*src) {
+		if (*src == '\\' && src[1] == '"')
+			src++;
+		else
+			*dst++ = *src++;
+	}
+	rv = new string(tmp);
+	delete tmp;
+	return *rv;
+}
+
 void
 var_list::set_variable(const string &var, const string &val)
 {
@@ -420,9 +446,9 @@ var_list::set_variable(const string &var, const string &val)
 	 * can consume excessive amounts of systime inside of connect().  Only
 	 * log when we're in -d mode.
 	 */
+	_vars[var] = fix_value(val);
 	if (no_daemon)
 		devdlog(LOG_DEBUG, "setting %s=%s\n", var.c_str(), val.c_str());
-	_vars[var] = val;
 }
 
 void
@@ -711,8 +737,13 @@ config::chop_var(char *&buffer, char *&lhs, char *&rhs) const
 	if (*walker == '"') {
 		walker++;	// skip "
 		rhs = walker;
-		while (*walker && *walker != '"')
+		while (*walker && *walker != '"') {
+			// Skip \" ... We leave it in the string and strip the \ later.
+			// due to the super simplistic parser that we have here.
+			if (*walker == '\\' && walker[1] == '"')
+				walker++;
 			walker++;
+		}
 		if (*walker != '"')
 			return (false);
 		rhs[-2] = '\0';