Commit ed363b36 authored by Stephen Morris's avatar Stephen Morris

[2981] Added storage of hooks library names to the DHCP config manager

parent dd01c785
......@@ -266,6 +266,24 @@ std::string CfgMgr::getDataDir() {
return (datadir_);
CfgMgr::setHooksLibraries(const std::vector<std::string>& hooks_libraries) {
hooks_libraries_.reset(new std::vector<std::string>(hooks_libraries));
boost::shared_ptr<std::vector<std::string> >
CfgMgr::getAndClearHooksLibraries() {
// Create shared pointer pointing to nothing.
boost::shared_ptr<std::vector<std::string> > libraries;
// Set the new variable to point to the stored hooks libraries and clear
// the stored value.
return (libraries);
:datadir_(DHCP_DATA_DIR) {
......@@ -38,10 +38,19 @@ namespace dhcp {
/// @brief Configuration Manager
/// This singleton class holds the whole configuration for DHCPv4 and DHCPv6
/// servers. It currently holds information about zero or more subnets6.
/// Each subnet may contain zero or more pools. Pool4 and Pool6 is the most
/// basic "chunk" of configuration. It contains a range of assignable
/// addresses.
/// servers. It currently holds information about:
/// - Zero or more subnets. Each subnet may contain zero or more pools. Pool4
/// and Pool6 is the most basic "chunk" of configuration. It contains a range
/// of assignable addresses.
/// - Hook libraries. Hooks library names are stored here, but only up to the
/// point that the libraries are reloaded. In more detail: libraries
/// containing hooks callouts can only be loaded and reloaded safely (or, more
/// accurately, unloaded safely) when no data structure in the server contains
/// a reference to any memory allocated by a function in them. In practice
/// this means when there are no packets being activly processed. Rather than
/// take a chance that the configuration code will do the unload/load at the
/// right time, the configuration code sets the names of the new libraries in
/// this object and the server decides when to reconfigure the hooks.
/// Below is a sketch of configuration inheritance (not implemented yet).
/// Let's investigate the following configuration:
......@@ -68,6 +77,7 @@ namespace dhcp {
/// routines, so there is no storage capability in a global scope for
/// subnet-specific parameters.
/// @todo: Implement Subnet4 support (ticket #2237)
/// @todo: Implement option definition support
/// @todo: Implement parameter inheritance
......@@ -229,7 +239,6 @@ public:
/// completely new?
void deleteSubnets4();
/// @brief returns path do the data directory
/// This method returns a path to writeable directory that DHCP servers
......@@ -237,6 +246,25 @@ public:
/// @return data directory
std::string getDataDir();
/// @brief Sets list of hooks libraries
/// Sets the list of hooks libraries. It is possible for there to be no
/// hooks libraries, in which case this is indicated by an emopty vector.
/// @param hooks_libraries Vector (possibly empty) of current hook libraries.
void setHooksLibraries(const std::vector<std::string>& hooks_libraries);
/// @brief Get and clear list of hooks libraries
/// Gets the currently-set vector of hooks libraries. If there is no data
/// (as opposed to an empty vector), there has been no change to the data
/// since the last time this method was called. Should there be a necessity
/// to know this information, it can be obtained from the HooksManager.
/// @return Pointer to vector of strings listing the hooks libraries. This
/// may be empty.
boost::shared_ptr<std::vector<std::string> > getAndClearHooksLibraries();
/// @brief Protected constructor.
......@@ -283,6 +311,28 @@ private:
/// @brief directory where data files (e.g. server-id) are stored
std::string datadir_;
/// @brief Hooks libraries
/// Unlike other configuration items that can be referenced all the time,
/// this is a "one-shot" item. When the list of libraries is altered, the
/// server needs to know about the change: once the libraries are loaded,
/// the list is ignored. As configuration updates cause an update of the
/// entire configuration and we wish to reload the libraries only if the
/// list has changed, we could check the library list against that stored
/// in the hooks manager. Unfortunately, since the libraries are reloaded
/// when a new packet is received, this would mean a set of string
/// comparisons on each packet. Instead, the data is flagged to indicate
/// that it has changed.
/// The parsing checks the set of hooks libraries in the configuration
/// against the list stored in the HooksManager and only updates the data
/// here if they have changed. Although a flag could be used to indicate
/// a change, a more streamlined approach is used: the data in this object
/// is cleared when it is read. As the data is a vector of strings and as
/// an empty vector is valid data, we'll store the data as a shared pointer
/// to a vector of strings. The pointer is zeroed when the data is read.
boost::shared_ptr<std::vector<std::string> > hooks_libraries_;
} // namespace isc::dhcp
......@@ -165,6 +165,7 @@ public:
/// @brief generates interface-id option based on provided text
......@@ -182,6 +183,7 @@ public:
......@@ -577,4 +579,35 @@ TEST_F(CfgMgrTest, optionSpace6) {
// in Dhcpv6SrvTest.selectSubnetAddr and Dhcpv6SrvTest.selectSubnetIface
// (see src/bin/dhcp6/tests/
// Checks that the hooks libraries can be set correctly.
TEST_F(CfgMgrTest, hooksLibraries) {
std::vector<std::string> test_libraries;
std::vector<std::string> no_libraries;
// The pointer should be empty initially.
boost::shared_ptr<std::vector<std::string> > config_libraries =
// Set the new set of libraries and get them.
config_libraries = CfgMgr::instance().getAndClearHooksLibraries();
EXPECT_TRUE(test_libraries == *config_libraries);
// Expect the get operation to have cleared the stored libraries.
config_libraries = CfgMgr::instance().getAndClearHooksLibraries();
// Check that the methods also work with an empty library vector.
config_libraries = CfgMgr::instance().getAndClearHooksLibraries();
} // end of anonymous namespace
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