1 // Copyright (C) 2013-2018 Internet Systems Consortium, Inc. ("ISC")
2 //
3 // This Source Code Form is subject to the terms of the Mozilla Public
4 // License, v. 2.0. If a copy of the MPL was not distributed with this
5 // file, You can obtain one at http://mozilla.org/MPL/2.0/.
6
7 #include <config.h>
8
9 #include <exceptions/exceptions.h>
10 #include <hooks/hooks_log.h>
11 #include <hooks/server_hooks.h>
12
13 #include <algorithm>
14 #include <utility>
15 #include <vector>
16
17 using namespace std;
18 using namespace isc;
19
20 namespace isc {
21 namespace hooks {
22
23 // Constructor - register the pre-defined hooks and check that the indexes
24 // assigned to them are as expected.
25 //
26 // Note that there are no logging messages here or in registerHooks(). The
27 // recommended way to initialize hook names is to use static initialization.
28 // Here, a static object is declared in a file outside of any function or
29 // method. As a result, it is instantiated and its constructor run before the
30 // program starts. By putting calls to ServerHooks::registerHook() in there,
31 // hooks names are already registered when the program runs. However, at that
32 // point, the logging system is not initialized, so messages are unable to
33 // be output.
34
ServerHooks()35 ServerHooks::ServerHooks() {
36 initialize();
37 }
38
39 // Register a hook. The index assigned to the hook is the current number
40 // of entries in the collection, so ensuring that hook indexes are unique
41 // and non-negative.
42
43 int
registerHook(const string & name)44 ServerHooks::registerHook(const string& name) {
45
46 // Determine index for the new element and insert.
47 int index = hooks_.size();
48 pair<HookCollection::iterator, bool> result =
49 hooks_.insert(make_pair(name, index));
50
51 /// @todo: We also need to call CalloutManager::ensureVectorSize(), so it
52 /// adjusts its vector. Since CalloutManager is not a singleton, there's
53 /// no getInstance() or similar. Also, CalloutManager uses ServerHooks,
54 /// so such a call would induce circular dependencies. Ugh.
55
56 if (!result.second) {
57
58 // There's a problem with hook libraries that need to be linked with
59 // libdhcpsrv. For example host_cmds hook library requires host
60 // parser, so it needs to be linked with libdhcpsrv. However, when
61 // unit-tests are started, the hook points are not registered.
62 // When the library is loaded new hook points are registered.
63 // This causes issues in the hooks framework, especially when
64 // LibraryManager::unloadLibrary() iterates through all hooks
65 // and then calls deregisterAllCallouts. This method gets
66 // hook_index that is greater than number of elements in
67 // hook_vector_ and then we have a read past the array boundary.
68 /// @todo: See ticket 5251 and 5208 for details.
69 return (getIndex(name));
70
71 // New element was not inserted because an element with the same name
72 // already existed.
73 //isc_throw(DuplicateHook, "hook with name " << name <<
74 // " is already registered");
75 }
76
77 // Element was inserted, so add to the inverse hooks collection.
78 inverse_hooks_[index] = name;
79
80 // ... and return numeric index.
81 return (index);
82 }
83
84 // Set ServerHooks object to initial state.
85
86 void
initialize()87 ServerHooks::initialize() {
88
89 // Clear out the name->index and index->name maps.
90 hooks_.clear();
91 inverse_hooks_.clear();
92 parking_lots_.reset(new ParkingLots());
93
94 // Register the pre-defined hooks.
95 int create = registerHook("context_create");
96 int destroy = registerHook("context_destroy");
97
98 // Check registration went as expected.
99 if ((create != CONTEXT_CREATE) || (destroy != CONTEXT_DESTROY)) {
100 isc_throw(Unexpected, "pre-defined hook indexes are not as expected. "
101 "context_create: expected = " << CONTEXT_CREATE <<
102 ", actual = " << create <<
103 ". context_destroy: expected = " << CONTEXT_DESTROY <<
104 ", actual = " << destroy);
105 }
106 }
107
108 // Reset ServerHooks object to initial state.
109
110 void
reset()111 ServerHooks::reset() {
112
113 // Clear all hooks then initialize the pre-defined ones.
114 initialize();
115
116 // Log a warning - although this is done during testing, it should never be
117 // seen in a production system.
118 LOG_WARN(hooks_logger, HOOKS_HOOK_LIST_RESET);
119 }
120
121 // Find the name associated with a hook index.
122
123 std::string
getName(int index) const124 ServerHooks::getName(int index) const {
125
126 // Get iterator to matching element.
127 InverseHookCollection::const_iterator i = inverse_hooks_.find(index);
128 if (i == inverse_hooks_.end()) {
129 isc_throw(NoSuchHook, "hook index " << index << " is not recognized");
130 }
131
132 return (i->second);
133 }
134
135 // Find the index associated with a hook name.
136
137 int
getIndex(const string & name) const138 ServerHooks::getIndex(const string& name) const {
139
140 // Get iterator to matching element.
141 HookCollection::const_iterator i = hooks_.find(name);
142 if (i == hooks_.end()) {
143 isc_throw(NoSuchHook, "hook name " << name << " is not recognized");
144 }
145
146 return (i->second);
147 }
148
149 int
findIndex(const std::string & name) const150 ServerHooks::findIndex(const std::string& name) const {
151 // Get iterator to matching element.
152 auto i = hooks_.find(name);
153 return ((i == hooks_.end()) ? -1 : i->second);
154 }
155
156 // Return vector of hook names. The names are not sorted - it is up to the
157 // caller to perform sorting if required.
158
159 vector<string>
getHookNames() const160 ServerHooks::getHookNames() const {
161
162 vector<string> names;
163 HookCollection::const_iterator i;
164 for (i = hooks_.begin(); i != hooks_.end(); ++i) {
165 names.push_back(i->first);
166 }
167
168 return (names);
169 }
170
171 // Return global ServerHooks object
172
173 ServerHooks&
getServerHooks()174 ServerHooks::getServerHooks() {
175 return (*getServerHooksPtr());
176 }
177
178 ServerHooksPtr
getServerHooksPtr()179 ServerHooks::getServerHooksPtr() {
180 static ServerHooksPtr hooks(new ServerHooks());
181 return (hooks);
182 }
183
184 ParkingLotsPtr
getParkingLotsPtr() const185 ServerHooks::getParkingLotsPtr() const {
186 return (parking_lots_);
187 }
188
189 ParkingLotPtr
getParkingLotPtr(const int hook_index)190 ServerHooks::getParkingLotPtr(const int hook_index) {
191 return (parking_lots_->getParkingLotPtr(hook_index));
192 }
193
194 ParkingLotPtr
getParkingLotPtr(const std::string & hook_name)195 ServerHooks::getParkingLotPtr(const std::string& hook_name) {
196 return (parking_lots_->getParkingLotPtr(getServerHooks().getIndex(hook_name)));
197 }
198
199 std::string
commandToHookName(const std::string & command_name)200 ServerHooks::commandToHookName(const std::string& command_name) {
201 // Prefix the command name with a dollar sign.
202 std::string hook_name = std::string("$") + command_name;
203 // Replace all hyphens with underscores.
204 std::replace(hook_name.begin(), hook_name.end(), '-', '_');
205 return (hook_name);
206 }
207
208 std::string
hookToCommandName(const std::string & hook_name)209 ServerHooks::hookToCommandName(const std::string& hook_name) {
210 if (!hook_name.empty() && hook_name.front() == '$') {
211 std::string command_name = hook_name.substr(1);
212 std::replace(command_name.begin(), command_name.end(), '_', '-');
213 return (command_name);
214 }
215 return ("");
216 }
217
218
219
220 } // namespace hooks
221 } // namespace isc
222