void caerConfigInit(const char *configFile, int argc, char *argv[]) {
// If configFile is NULL, no config file will be accessed at all,
// and neither will it be written back at shutdown.
if (configFile != NULL) {
// Let's try to open the file for reading, or create it.
int configFileFd = open(configFile, O_RDONLY | O_CREAT, S_IWUSR | S_IRUSR | S_IRGRP);
if (configFileFd >= 0) {
// File opened for reading successfully.
// This means it exists and we can access it, so let's remember
// it for writing the config later at shutdown (if permitted).
caerConfigFilePath = realpath(configFile, NULL);
// Determine if there is actual content to parse first.
struct stat configFileStat;
fstat(configFileFd, &configFileStat);
if (configFileStat.st_size > 0) {
sshsNodeImportSubTreeFromXML(sshsGetNode(sshsGetGlobal(), "/"), configFileFd, true);
}
close(configFileFd);
// Ensure configuration is written back at shutdown.
atexit(&caerConfigShutDownWriteBack);
}
else {
caerLog(CAER_LOG_EMERGENCY, "Config",
"Could not create and/or read from the configuration file '%s'. Error: %d.", configFile, errno);
exit(EXIT_FAILURE);
}
}
else {
caerLog(CAER_LOG_EMERGENCY, "Config", "No configuration file defined, using default values for everything.");
}
// Override with command line arguments if requested.
if (argc > 1) {
// Format: -o node key type value (5 arguments). Equal to caerctl format.
for (size_t i = 1; i < (size_t) argc; i += 5) {
if ((i + 4) < (size_t) argc && caerStrEquals(argv[i], "-o")) {
sshsNode node = sshsGetNode(sshsGetGlobal(), argv[i + 1]);
if (node == NULL) {
caerLog(CAER_LOG_EMERGENCY, "Config", "SSHS Node %s doesn't exist.", argv[i + 1]);
continue;
}
if (!sshsNodeStringToNodeConverter(node, argv[i + 2], argv[i + 3], argv[i + 4])) {
caerLog(CAER_LOG_EMERGENCY, "Config", "Failed to convert attribute %s of type %s with value %s.",
argv[i + 2], argv[i + 3], argv[i + 4]);
}
}
}
}
}
void caerConfigWriteBack(void) {
if (caerConfigFilePath != NULL) {
int configFileFd = open(caerConfigFilePath, O_WRONLY | O_TRUNC);
if (configFileFd >= 0) {
sshsNodeExportSubTreeToXML(sshsGetNode(sshsGetGlobal(), "/"), configFileFd, (const char *[] ) { "running",
"connectedClients" }, 2, (const char *[] ) { "sourceInfo" }, 1);
static int caerConfigServerRunner(void *inPtr) {
UNUSED_ARGUMENT(inPtr);
// Get the right configuration node first.
sshsNode serverNode = sshsGetNode(sshsGetGlobal(), "/server/");
// Ensure default values are present.
sshsNodePutStringIfAbsent(serverNode, "ipAddress", "127.0.0.1");
sshsNodePutIntIfAbsent(serverNode, "portNumber", 4040);
sshsNodePutShortIfAbsent(serverNode, "backlogSize", 5);
sshsNodePutShortIfAbsent(serverNode, "concurrentConnections", 5);
// Open a TCP server socket for configuration handling.
// TCP chosen for reliability, which is more important here than speed.
int configServerSocket = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
if (configServerSocket < 0) {
caerLog(CAER_LOG_CRITICAL, "Config Server", "Could not create server socket. Error: %d.", errno);
return (EXIT_FAILURE);
}
// Make socket address reusable right away.
socketReuseAddr(configServerSocket, true);
struct sockaddr_in configServerAddress;
memset(&configServerAddress, 0, sizeof(struct sockaddr_in));
configServerAddress.sin_family = AF_INET;
configServerAddress.sin_port = htons(sshsNodeGetInt(serverNode, "portNumber"));
char *ipAddress = sshsNodeGetString(serverNode, "ipAddress");
inet_aton(ipAddress, &configServerAddress.sin_addr); // htonl() is implicit here.
free(ipAddress);
// Bind socket to above address.
if (bind(configServerSocket, (struct sockaddr *) &configServerAddress, sizeof(struct sockaddr_in)) < 0) {
caerLog(CAER_LOG_CRITICAL, "Config Server", "Could not bind server socket. Error: %d.", errno);
return (EXIT_FAILURE);
}
// Listen to new connections on the socket.
if (listen(configServerSocket, sshsNodeGetShort(serverNode, "backlogSize")) < 0) {
caerLog(CAER_LOG_CRITICAL, "Config Server", "Could not listen on server socket. Error: %d.", errno);
return (EXIT_FAILURE);
}
// Control message format: 1 byte ACTION, 1 byte TYPE, 2 bytes EXTRA_LEN,
// 2 bytes NODE_LEN, 2 bytes KEY_LEN, 2 bytes VALUE_LEN, then up to 4086
// bytes split between EXTRA, NODE, KEY, VALUE (with 4 bytes for NUL).
// Basically: (EXTRA_LEN + NODE_LEN + KEY_LEN + VALUE_LEN) <= 4086.
// EXTRA, NODE, KEY, VALUE have to be NUL terminated, and their length
// must include the NUL termination byte.
// This results in a maximum message size of 4096 bytes (4KB).
uint8_t configServerBuffer[4096];
caerLog(CAER_LOG_NOTICE, "Config Server", "Ready and listening on %s:%" PRIu16 ".",
inet_ntoa(configServerAddress.sin_addr), ntohs(configServerAddress.sin_port));
size_t connections = (size_t) sshsNodeGetShort(serverNode, "concurrentConnections") + 1;// +1 for listening socket.
struct pollfd pollSockets[connections];
// Initially ignore all pollfds, and react only to POLLIN events.
for (size_t i = 0; i < connections; i++) {
pollSockets[i].fd = -1;
pollSockets[i].events = POLLIN;
}
// First pollfd is the listening socket, always.
pollSockets[0].fd = configServerSocket;
while (atomic_load_explicit(&configServerThread.running, memory_order_relaxed)) {
int pollResult = poll(pollSockets, (nfds_t) connections, 1000);
if (pollResult > 0) {
// First let's check if there's a new connection waiting to be accepted.
if ((pollSockets[0].revents & POLLIN) != 0) {
int newClientSocket = accept(pollSockets[0].fd, NULL, NULL);
if (newClientSocket >= 0) {
// Put it in the list of watched fds if possible, or close.
bool putInFDList = false;
for (size_t i = 1; i < connections; i++) {
if (pollSockets[i].fd == -1) {
// Empty place in watch list, add this one.
pollSockets[i].fd = newClientSocket;
putInFDList = true;
break;
}
}
// No space for new connection, just close it (client will exit).
if (!putInFDList) {
close(newClientSocket);
caerLog(CAER_LOG_DEBUG, "Config Server", "Rejected client (fd %d), queue full.",
newClientSocket);
}
else {
caerLog(CAER_LOG_DEBUG, "Config Server", "Accepted new connection from client (fd %d).",
newClientSocket);
}
}
}
for (size_t i = 1; i < connections; i++) {
// Work on existing connections, valid and with read events.
if (pollSockets[i].fd != -1 && (pollSockets[i].revents & POLLIN) != 0) {
// Accepted client connection, let's get all the data we need: first
// the 10 byte header, and then whatever remains based on that.
if (!recvUntilDone(pollSockets[i].fd, configServerBuffer, 10)) {
// Closed on other side or error. Let's just close here too.
close(pollSockets[i].fd);
caerLog(CAER_LOG_DEBUG, "Config Server", "Disconnected client on recv (fd %d).",
pollSockets[i].fd);
pollSockets[i].fd = -1;
continue;
}
// Decode header fields (all in little-endian).
uint8_t action = configServerBuffer[0];
uint8_t type = configServerBuffer[1];
uint16_t extraLength = le16toh(*(uint16_t * )(configServerBuffer + 2));
uint16_t nodeLength = le16toh(*(uint16_t * )(configServerBuffer + 4));
uint16_t keyLength = le16toh(*(uint16_t * )(configServerBuffer + 6));
uint16_t valueLength = le16toh(*(uint16_t * )(configServerBuffer + 8));
// Total length to get for command.
size_t readLength = (size_t) (extraLength + nodeLength + keyLength + valueLength);
if (!recvUntilDone(pollSockets[i].fd, configServerBuffer + 10, readLength)) {
// Closed on other side or error. Let's just close here too.
close(pollSockets[i].fd);
caerLog(CAER_LOG_DEBUG, "Config Server", "Disconnected client on recv (fd %d).",
pollSockets[i].fd);
pollSockets[i].fd = -1;
continue;
}
// Now we have everything. The header fields are already
// fully decoded: handle request (and send back data eventually).
caerConfigServerHandleRequest(pollSockets[i].fd, action, type, configServerBuffer + 10, extraLength,
configServerBuffer + 10 + extraLength, nodeLength,
configServerBuffer + 10 + extraLength + nodeLength, keyLength,
configServerBuffer + 10 + extraLength + nodeLength + keyLength, valueLength);
}
}
}
else if (pollResult < 0) {
caerLog(CAER_LOG_ALERT, "Config Server", "poll() failed. Error: %d.", errno);
}
// pollResult == 0 just means nothing to do (timeout reached).
}
// Shutdown!
close(configServerSocket);
return (EXIT_SUCCESS);
}
static void caerConfigServerHandleRequest(int connectedClientSocket, uint8_t action, uint8_t type, const uint8_t *extra,
size_t extraLength, const uint8_t *node, size_t nodeLength, const uint8_t *key, size_t keyLength,
const uint8_t *value, size_t valueLength) {
UNUSED_ARGUMENT(extra);
caerLog(CAER_LOG_DEBUG, "Config Server",
"Handling request: action=%" PRIu8 ", type=%" PRIu8 ", extraLength=%zu, nodeLength=%zu, keyLength=%zu, valueLength=%zu.",
action, type, extraLength, nodeLength, keyLength, valueLength);
// Interpretation of data is up to each action individually.
sshs configStore = sshsGetGlobal();
switch (action) {
case NODE_EXISTS: {
// We only need the node name here. Type is not used (ignored)!
bool result = sshsExistsNode(configStore, (const char *) node);
// Send back result to client. Format is the same as incoming data.
const uint8_t *sendResult = (const uint8_t *) ((result) ? ("true") : ("false"));
size_t sendResultLength = (result) ? (5) : (6);
caerConfigSendResponse(connectedClientSocket, NODE_EXISTS, BOOL, sendResult, sendResultLength);
break;
}
case ATTR_EXISTS: {
bool nodeExists = sshsExistsNode(configStore, (const char *) node);
// Only allow operations on existing nodes, this is for remote
// control, so we only manipulate what's already there!
if (!nodeExists) {
// Send back error message to client.
caerConfigSendError(connectedClientSocket,
"Node doesn't exist. Operations are only allowed on existing data.");
break;
}
// This cannot fail, since we know the node exists from above.
sshsNode wantedNode = sshsGetNode(configStore, (const char *) node);
// Check if attribute exists.
bool result = sshsNodeAttributeExists(wantedNode, (const char *) key, type);
// Send back result to client. Format is the same as incoming data.
const uint8_t *sendResult = (const uint8_t *) ((result) ? ("true") : ("false"));
size_t sendResultLength = (result) ? (5) : (6);
caerConfigSendResponse(connectedClientSocket, ATTR_EXISTS, BOOL, sendResult, sendResultLength);
break;
}
case GET: {
bool nodeExists = sshsExistsNode(configStore, (const char *) node);
// Only allow operations on existing nodes, this is for remote
// control, so we only manipulate what's already there!
if (!nodeExists) {
// Send back error message to client.
caerConfigSendError(connectedClientSocket,
"Node doesn't exist. Operations are only allowed on existing data.");
break;
}
// This cannot fail, since we know the node exists from above.
sshsNode wantedNode = sshsGetNode(configStore, (const char *) node);
// Check if attribute exists. Only allow operations on existing attributes!
bool attrExists = sshsNodeAttributeExists(wantedNode, (const char *) key, type);
if (!attrExists) {
// Send back error message to client.
caerConfigSendError(connectedClientSocket,
"Attribute of given type doesn't exist. Operations are only allowed on existing data.");
break;
}
union sshs_node_attr_value result = sshsNodeGetAttribute(wantedNode, (const char *) key, type);
char *resultStr = sshsHelperValueToStringConverter(type, result);
if (resultStr == NULL) {
// Send back error message to client.
caerConfigSendError(connectedClientSocket, "Failed to allocate memory for value string.");
}
else {
caerConfigSendResponse(connectedClientSocket, GET, type, (const uint8_t *) resultStr,
strlen(resultStr) + 1);
free(resultStr);
}
// If this is a string, we must remember to free the original result.str
// too, since it will also be a copy of the string coming from SSHS.
if (type == STRING) {
free(result.string);
}
break;
}
case PUT: {
bool nodeExists = sshsExistsNode(configStore, (const char *) node);
// Only allow operations on existing nodes, this is for remote
// control, so we only manipulate what's already there!
if (!nodeExists) {
// Send back error message to client.
caerConfigSendError(connectedClientSocket,
"Node doesn't exist. Operations are only allowed on existing data.");
break;
}
// This cannot fail, since we know the node exists from above.
sshsNode wantedNode = sshsGetNode(configStore, (const char *) node);
// Check if attribute exists. Only allow operations on existing attributes!
bool attrExists = sshsNodeAttributeExists(wantedNode, (const char *) key, type);
if (!attrExists) {
// Send back error message to client.
caerConfigSendError(connectedClientSocket,
"Attribute of given type doesn't exist. Operations are only allowed on existing data.");
break;
}
// Put given value into config node. Node, attr and type are already verified.
const char *typeStr = sshsHelperTypeToStringConverter(type);
if (!sshsNodeStringToNodeConverter(wantedNode, (const char *) key, typeStr, (const char *) value)) {
// Send back error message to client.
caerConfigSendError(connectedClientSocket, "Impossible to convert value according to type.");
break;
}
// Send back confirmation to the client.
caerConfigSendResponse(connectedClientSocket, PUT, BOOL, (const uint8_t *) "true", 5);
break;
}
case GET_CHILDREN: {
bool nodeExists = sshsExistsNode(configStore, (const char *) node);
// Only allow operations on existing nodes, this is for remote
// control, so we only manipulate what's already there!
if (!nodeExists) {
// Send back error message to client.
caerConfigSendError(connectedClientSocket,
"Node doesn't exist. Operations are only allowed on existing data.");
break;
}
// This cannot fail, since we know the node exists from above.
sshsNode wantedNode = sshsGetNode(configStore, (const char *) node);
// Get the names of all the child nodes and return them.
size_t numNames;
const char **childNames = sshsNodeGetChildNames(wantedNode, &numNames);
// No children at all, return empty.
if (childNames == NULL) {
// Send back error message to client.
caerConfigSendError(connectedClientSocket, "Node has no children.");
break;
}
// We need to return a big string with all of the child names,
// separated by a NUL character.
size_t namesLength = 0;
for (size_t i = 0; i < numNames; i++) {
namesLength += strlen(childNames[i]) + 1; // +1 for terminating NUL byte.
}
// Allocate a buffer for the names and copy them over.
char namesBuffer[namesLength];
for (size_t i = 0, acc = 0; i < numNames; i++) {
size_t len = strlen(childNames[i]) + 1;
memcpy(namesBuffer + acc, childNames[i], len);
acc += len;
}
caerConfigSendResponse(connectedClientSocket, GET_CHILDREN, STRING, (const uint8_t *) namesBuffer,
namesLength);
break;
}
case GET_ATTRIBUTES: {
bool nodeExists = sshsExistsNode(configStore, (const char *) node);
// Only allow operations on existing nodes, this is for remote
// control, so we only manipulate what's already there!
if (!nodeExists) {
// Send back error message to client.
caerConfigSendError(connectedClientSocket,
"Node doesn't exist. Operations are only allowed on existing data.");
break;
}
// This cannot fail, since we know the node exists from above.
sshsNode wantedNode = sshsGetNode(configStore, (const char *) node);
// Get the keys of all the attributes and return them.
size_t numKeys;
const char **attrKeys = sshsNodeGetAttributeKeys(wantedNode, &numKeys);
// No attributes at all, return empty.
if (attrKeys == NULL) {
// Send back error message to client.
caerConfigSendError(connectedClientSocket, "Node has no attributes.");
break;
}
// We need to return a big string with all of the attribute keys,
// separated by a NUL character.
size_t keysLength = 0;
for (size_t i = 0; i < numKeys; i++) {
keysLength += strlen(attrKeys[i]) + 1; // +1 for terminating NUL byte.
}
// Allocate a buffer for the keys and copy them over.
char keysBuffer[keysLength];
for (size_t i = 0, acc = 0; i < numKeys; i++) {
size_t len = strlen(attrKeys[i]) + 1;
memcpy(keysBuffer + acc, attrKeys[i], len);
acc += len;
}
caerConfigSendResponse(connectedClientSocket, GET_ATTRIBUTES, STRING, (const uint8_t *) keysBuffer,
keysLength);
break;
}
case GET_TYPES: {
bool nodeExists = sshsExistsNode(configStore, (const char *) node);
// Only allow operations on existing nodes, this is for remote
// control, so we only manipulate what's already there!
if (!nodeExists) {
// Send back error message to client.
caerConfigSendError(connectedClientSocket,
"Node doesn't exist. Operations are only allowed on existing data.");
break;
}
// This cannot fail, since we know the node exists from above.
sshsNode wantedNode = sshsGetNode(configStore, (const char *) node);
// Check if any keys match the given one and return its types.
size_t numTypes;
enum sshs_node_attr_value_type *attrTypes = sshsNodeGetAttributeTypes(wantedNode, (const char *) key,
&numTypes);
// No attributes for specified key, return empty.
if (attrTypes == NULL) {
// Send back error message to client.
caerConfigSendError(connectedClientSocket, "Node has no attributes with specified key.");
break;
}
// We need to return a big string with all of the attribute types,
// separated by a NUL character.
size_t typesLength = 0;
for (size_t i = 0; i < numTypes; i++) {
const char *typeString = sshsHelperTypeToStringConverter(attrTypes[i]);
typesLength += strlen(typeString) + 1; // +1 for terminating NUL byte.
}
// Allocate a buffer for the types and copy them over.
char typesBuffer[typesLength];
for (size_t i = 0, acc = 0; i < numTypes; i++) {
const char *typeString = sshsHelperTypeToStringConverter(attrTypes[i]);
size_t len = strlen(typeString) + 1;
memcpy(typesBuffer + acc, typeString, len);
acc += len;
}
caerConfigSendResponse(connectedClientSocket, GET_TYPES, STRING, (const uint8_t *) typesBuffer,
typesLength);
break;
}
default:
// Unknown action, send error back to client.
caerConfigSendError(connectedClientSocket, "Unknown action.");
break;
}
}
