diff options
Diffstat (limited to 'src/mds-registry')
| -rw-r--r-- | src/mds-registry/mds-registry.c | 890 | ||||
| -rw-r--r-- | src/mds-registry/mds-registry.h | 91 |
2 files changed, 981 insertions, 0 deletions
diff --git a/src/mds-registry/mds-registry.c b/src/mds-registry/mds-registry.c new file mode 100644 index 0000000..b0c6962 --- /dev/null +++ b/src/mds-registry/mds-registry.c @@ -0,0 +1,890 @@ +/** + * mds — A micro-display server + * Copyright © 2014 Mattias Andrée (maandree@member.fsf.org) + * + * This program is free software: you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation, either version 3 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program. If not, see <http://www.gnu.org/licenses/>. + */ +#include "mds-registry.h" + +#include <libmdsserver/macros.h> +#include <libmdsserver/util.h> +#include <libmdsserver/mds-message.h> +#include <libmdsserver/hash-table.h> +#include <libmdsserver/hash-help.h> +#include <libmdsserver/client-list.h> + +#include <errno.h> +#include <inttypes.h> +#include <string.h> +#include <stdio.h> +#include <stdlib.h> +#define reconnect_to_display() -1 /* TODO */ + + + +#define MDS_REGISTRY_VARS_VERSION 0 + + + +/** + * This variable should declared by the actual server implementation. + * It must be configured before `main` is invoked. + * + * This tells the server-base how to behave + */ +server_characteristics_t server_characteristics = + { + .require_privileges = 0, + .require_display = 1, + .require_respawn_info = 0, + .sanity_check_argc = 1 + }; + + + +/** + * Value of the ‘Message ID’ header for the next message + */ +static int32_t message_id = 2; + +/** + * Buffer for received messages + */ +static mds_message_t received; + +/** + * Whether the server is connected to the display + */ +static int connected = 1; + +/** + * Protocol registry table + */ +static hash_table_t reg_table; + +/** + * Reusable buffer for data to send + */ +static char* send_buffer = NULL; + +/** + * The size of `send_buffer` + */ +static size_t send_buffer_size = 0; + +/** + * General mutex + */ +static pthread_mutex_t reg_mutex; + +/** + * General condition + */ +static pthread_cond_t reg_cond; + +/** + * Used to temporarily store the old value when reallocating heap-allocations + */ +static char* old; + + + +/** + * This function will be invoked before `initialise_server` (if not re-exec:ing) + * or before `unmarshal_server` (if re-exec:ing) + * + * @return Non-zero on error + */ +int __attribute__((const)) preinitialise_server(void) +{ + if ((errno = pthread_mutex_init(®_mutex, NULL))) + { + perror(*argv); + return 1; + } + + if ((errno = pthread_cond_init(®_cond, NULL))) + { + perror(*argv); + pthread_mutex_destroy(®_mutex); + return 1; + } + + return 0; +} + + +/** + * This function should initialise the server, + * and it not invoked after a re-exec. + * + * @return Non-zero on error + */ +int initialise_server(void) +{ + const char* const message = + "Command: intercept\n" + "Message ID: 0\n" + "Length: 32\n" + "\n" + "Command: register\n" + "Client closed\n" + /* -- NEXT MESSAGE -- */ + "Command: reregister\n" + "Message ID: 1\n" + "\n"; + + /* We are asking all servers to reregister their + protocols for two reasons: + + 1) The server would otherwise not get registrations + from servers started before this server. + 2) If this server crashes we may miss registrations + that happen between the crash and the recovery. + */ + + if (full_send(message, strlen(message))) + return 1; + if (hash_table_create_tuned(®_table, 32)) + { + perror(*argv); + hash_table_destroy(®_table, NULL, NULL); + return 1; + } + reg_table.key_comparator = (compare_func*)string_comparator; + reg_table.hasher = (hash_func*)string_hash; + server_initialised(); + mds_message_initialise(&received); + return 0; +} + + +/** + * This function will be invoked after `initialise_server` (if not re-exec:ing) + * or after `unmarshal_server` (if re-exec:ing) + * + * @return Non-zero on error + */ +int postinitialise_server(void) +{ + if (connected) + return 0; + + if (reconnect_to_display()) + { + mds_message_destroy(&received); + return 1; + } + connected = 1; + return 0; +} + + +/** + * Calculate the number of bytes that will be stored by `marshal_server` + * + * On failure the program should `abort()` or exit by other means. + * However it should not be possible for this function to fail. + * + * @return The number of bytes that will be stored by `marshal_server` + */ +size_t marshal_server_size(void) +{ + size_t i, rc = 2 * sizeof(int) + sizeof(int32_t) + 3 * sizeof(size_t); + hash_entry_t* entry; + + rc += mds_message_marshal_size(&received); + + foreach_hash_table_entry (reg_table, i, entry) + { + char* command = (char*)(void*)(entry->key); + size_t len = strlen(command) + 1; + client_list_t* list = (client_list_t*)(void*)(entry->value); + + rc += len + sizeof(size_t) + client_list_marshal_size(list); + } + + return rc; +} + + +/** + * Marshal server implementation specific data into a buffer + * + * @param state_buf The buffer for the marshalled data + * @return Non-zero on error + */ +int marshal_server(char* state_buf) +{ + size_t i, n = mds_message_marshal_size(&received); + hash_entry_t* entry; + + buf_set_next(state_buf, int, MDS_REGISTRY_VARS_VERSION); + buf_set_next(state_buf, int, connected); + buf_set_next(state_buf, int32_t, message_id); + buf_set_next(state_buf, size_t, n); + mds_message_marshal(&received, state_buf); + state_buf += n / sizeof(char); + + buf_set_next(state_buf, size_t, reg_table.capacity); + buf_set_next(state_buf, size_t, reg_table.size); + foreach_hash_table_entry (reg_table, i, entry) + { + char* command = (char*)(void*)(entry->key); + size_t len = strlen(command) + 1; + client_list_t* list = (client_list_t*)(void*)(entry->value); + + memcpy(state_buf, command, len * sizeof(char)); + state_buf += len; + + n = client_list_marshal_size(list); + buf_set_next(state_buf, size_t, n); + client_list_marshal(list, state_buf); + state_buf += n / sizeof(char); + } + + hash_table_destroy(®_table, (free_func*)reg_table_free_key, (free_func*)reg_table_free_value); + mds_message_destroy(&received); + return 0; +} + + +/** + * Unmarshal server implementation specific data and update the servers state accordingly + * + * On critical failure the program should `abort()` or exit by other means. + * That is, do not let `reexec_failure_recover` run successfully, if it unrecoverable + * error has occurred or one severe enough that it is better to simply respawn. + * + * @param state_buf The marshalled data that as not been read already + * @return Non-zero on error + */ +int unmarshal_server(char* state_buf) +{ + char* command; + client_list_t* list; + size_t i, n, m; + int stage = 0; + + /* buf_get_next(state_buf, int, MDS_REGISTRY_VARS_VERSION); */ + buf_next(state_buf, int, 1); + buf_get_next(state_buf, int, connected); + buf_get_next(state_buf, int32_t, message_id); + buf_get_next(state_buf, size_t, n); + fail_if (mds_message_unmarshal(&received, state_buf)); + state_buf += n / sizeof(char); + stage = 1; + + buf_get_next(state_buf, size_t, n); + fail_if (hash_table_create_tuned(®_table, n)); + buf_get_next(state_buf, size_t, n); + for (i = 0; i < n; i++) + { + stage = 1; + fail_if ((command = strdup(state_buf)) == NULL); + state_buf += strlen(command) + 1; + + stage = 2; + fail_if ((list = malloc(sizeof(client_list_t))) == NULL); + buf_get_next(state_buf, size_t, m); + stage = 3; + fail_if (client_list_unmarshal(list, state_buf)); + state_buf += m / sizeof(char); + + hash_table_put(®_table, (size_t)(void*)command, (size_t)(void*)list); + fail_if (errno); + } + + reg_table.key_comparator = (compare_func*)string_comparator; + reg_table.hasher = (hash_func*)string_hash; + + return 0; + pfail: + perror(*argv); + mds_message_destroy(&received); + if (stage >= 1) + hash_table_destroy(®_table, (free_func*)reg_table_free_key, (free_func*)reg_table_free_value); + if (stage >= 2) + free(command); + if (stage >= 3) + { + client_list_destroy(list); + free(list); + } + abort(); + return -1; +} + + +/** + * Attempt to recover from a re-exec failure that has been + * detected after the server successfully updated it execution image + * + * @return Non-zero on error + */ +int __attribute__((const)) reexec_failure_recover(void) +{ + return -1; +} + + +/** + * Perform the server's mission + * + * @return Non-zero on error + */ +int master_loop(void) +{ + int rc = 1; + + while (!reexecing && !terminating) + { + int r = mds_message_read(&received, socket_fd); + if (r == 0) + { + r = handle_message(); + if (r == 0) + continue; + } + + if (r == -2) + { + eprint("corrupt message received, aborting."); + goto fail; + } + else if (errno == EINTR) + continue; + else if (errno != ECONNRESET) + goto pfail; + + eprint("lost connection to server."); + mds_message_destroy(&received); + mds_message_initialise(&received); + connected = 0; + if (reconnect_to_display()) + goto fail; + connected = 1; + } + + rc = 0; + goto fail; + pfail: + perror(*argv); + fail: + if (rc || !reexecing) + { + hash_table_destroy(®_table, (free_func*)reg_table_free_key, (free_func*)reg_table_free_value); + mds_message_destroy(&received); + } + pthread_mutex_destroy(®_mutex); + pthread_cond_destroy(®_cond); + free(send_buffer); + return rc; +} + + +/** + * Handle the received message containing ‘Command: register’-header–value + * + * @return Zero on success -1 on error or interruption, + * errno will be set accordingly + */ +static int handle_register_message(void) +{ + const char* recv_client_id = NULL; + const char* recv_message_id = NULL; + const char* recv_length = NULL; + const char* recv_action = NULL; + size_t i, length = 0; + +#define __get_header(storage, header) \ + (startswith(received.headers[i], header)) \ + storage = received.headers[i] + strlen(header) + + for (i = 0; i < received.header_count; i++) + { + if __get_header(recv_client_id, "Client ID: "); + else if __get_header(recv_message_id, "Message ID: "); + else if __get_header(recv_length, "Length: "); + else if __get_header(recv_action, "Action: "); + else + continue; + if (recv_client_id && recv_message_id && recv_length && recv_action) + break; + } + +#undef __get_header + + + if ((recv_client_id == NULL) || (strequals(recv_client_id, "0:0"))) + { + eprint("received message from anonymous sender, ignoring."); + return 0; + } + else if (strchr(recv_client_id, ':') == NULL) + { + eprint("received message from sender without a colon it its ID, ignoring, invalid ID."); + return 0; + } + else if ((recv_length == NULL) && ((recv_action == NULL) || !strequals(recv_action, "list"))) + { + eprint("received empty message without `Action: list`, ignoring, has no effect."); + return 0; + } + else if (recv_message_id == NULL) + { + eprint("received message with ID, ignoring, master server is misbehaving."); + return 0; + } + + + if (recv_length != NULL) + length = (size_t)atoll(recv_length); + if (recv_action != NULL) + recv_action = "add"; + +#define __registry_action(action) registry_action(length, action, recv_client_id, recv_message_id) + + if (strequals(recv_action, "add")) return __registry_action(1); + else if (strequals(recv_action, "remove")) return __registry_action(-1); + else if (strequals(recv_action, "wait")) return __registry_action(0); + else if (strequals(recv_action, "list")) return list_registry(recv_client_id, recv_message_id); + else + { + eprint("received invalid action, ignoring."); + return 0; + } + +#undef __registry_action +} + + +/** + * Handle the received message containing a ‘Client closed’-header + * + * @return Zero on success -1 on error or interruption, + * errno will be set accordingly + */ +static int handle_close_message(void) +{ + /* Servers do not close too often, there is no need to + optimise this with another hash table. */ + + size_t i, j, ptr = 0, size = 1; + size_t* keys = NULL; + size_t* old_keys; + + fail_if ((errno = pthread_mutex_lock(®_mutex))); + + for (i = 0; i < received.header_count; i++) + if (startswith(received.headers[i], "Client closed: ")) + { + uint64_t client = parse_client_id(received.headers[i] + strlen("Client closed: ")); + hash_entry_t* entry; + + foreach_hash_table_entry (reg_table, j, entry) + { + client_list_t* list = (client_list_t*)(void*)(entry->value); + client_list_remove(list, client); + if (list->size) + continue; + + fail_if ((keys == NULL) && xmalloc(keys, size, size_t)); + if (ptr == size ? growalloc(old_keys, keys, size, size_t) : 0) + goto fail; + keys[ptr++] = entry->key; + } + } + + for (i = 0; i < ptr; i++) + { + hash_entry_t* entry = hash_table_get_entry(®_table, keys[i]); + client_list_t* list = (client_list_t*)(void*)(entry->value); + char* command = (char*)(void*)(entry->key); + + hash_table_remove(®_table, entry->key); + + client_list_destroy(list); + free(list); + free(command); + } + + pthread_mutex_unlock(®_mutex); + + free(keys); + return 0; + pfail: + perror(*argv); + fail: + free(keys); + return -1; +} + + +/** + * Handle the received message + * + * @return Zero on success -1 on error or interruption, + * errno will be set accordingly + */ +int handle_message(void) +{ + size_t i; + for (i = 0; i < received.header_count; i++) + if (strequals(received.headers[i], "Command: register")) + return handle_register_message(); + return handle_close_message(); +} + + +/** + * Convert a client ID string into a client ID integer + * + * @param str The client ID string + * @return The client ID integer + */ +uint64_t parse_client_id(const char* str) +{ + char client_words[22]; + char* client_high; + char* client_low; + uint64_t client; + + strcpy(client_high = client_words, str); + client_low = rawmemchr(client_words, ':'); + *client_low++ = '\0'; + client = (uint64_t)atoll(client_high); + client <<= 32; + client |= (uint64_t)atoll(client_low); + + return client; +} + + +/** + * Add a protocol to the registry + * + * @param has_key Whether the command is already in the registry + * @param command The command + * @param command_key The address of `command` + * @param client The ID of the client that implements the server-side of the protocol + * @return Non-zero on error + */ +static int registry_action_add(int has_key, char* command, size_t command_key, uint64_t client) +{ + if (has_key) + { + size_t address = hash_table_get(®_table, command_key); + client_list_t* list = (client_list_t*)(void*)address; + if (client_list_add(list, client) < 0) + goto pfail; + } + else + { + client_list_t* list = malloc(sizeof(client_list_t)); + void* address = list; + if (list == NULL) + goto pfail; + if ((command = strdup(command)) == NULL) + { + free(list); + goto pfail; + } + command_key = (size_t)(void*)command; + if (client_list_create(list, 1) || + client_list_add(list, client) || + (hash_table_put(®_table, command_key, (size_t)address) == 0)) + { + client_list_destroy(list); + free(list); + free(command); + goto pfail; + } + } + + return 0; + pfail: + perror(*argv); + return -1; +} + + +/** + * Remove a protocol from the registry + * + * @param command_key The address of a string that contains the command + * @param client The ID of the client that implements the server-side of the protocol + * @return Non-zero on error + */ +static void registry_action_remove(size_t command_key, uint64_t client) +{ + hash_entry_t* entry = hash_table_get_entry(®_table, command_key); + size_t address = entry->value; + client_list_t* list = (client_list_t*)(void*)address; + client_list_remove(list, client); + if (list->size == 0) + { + client_list_destroy(list); + free(list); + hash_table_remove(®_table, command_key); + reg_table_free_key(entry->key); + } +} + + +/** + * Modify the protocol registry or list missing protocols + * + * @param command The command + * @param action -1 to remove command, +1 to add commands, 0 to + * wait until the message commnds are registered + * @param client The ID of the client that implements the server-side of the protocol + * @param wait_set Table to fill with missing protocols if `action == 0` + * @return Non-zero on error + */ +static int registry_action_act(char* command, int action, uint64_t client, hash_table_t* wait_set) +{ + size_t command_key = (size_t)(void*)command; + int has_key = hash_table_contains_key(®_table, command_key); + + if (action == 1) + { + if (registry_action_add(has_key, command, command_key, client)) + return -1; + } + else if ((action == -1) && has_key) + registry_action_remove(command_key, client); + else if ((action == 0) && !has_key) + { + if ((command = strdup(command)) == NULL) + goto pfail_wait; + command_key = (size_t)(void*)command; + if (hash_table_put(wait_set, command_key, 1) == 0) + if (errno) + { + free(command); + goto pfail_wait; + } + } + + return 0; + pfail_wait: + perror(*argv); + hash_table_destroy(wait_set, (free_func*)reg_table_free_key, NULL); + free(wait_set); + return -1; +} + + +/** + * Perform an action over the registry + * + * @param length The length of the received message + * @param action -1 to remove command, +1 to add commands, 0 to + * wait until the message commnds are registered + * @param recv_client_id The ID of the client + * @param recv_message_id The ID of the received message + * @return Zero on success -1 on error or interruption, + * errno will be set accordingly + */ +int registry_action(size_t length, int action, const char* recv_client_id, const char* recv_message_id) +{ + char* payload = received.payload; + uint64_t client = action ? parse_client_id(recv_client_id) : 0; + hash_table_t* wait_set = NULL; + size_t begin; + + if (action == 0) + { + wait_set = malloc(sizeof(hash_table_t)); + if (hash_table_create(wait_set)) + { + hash_table_destroy(wait_set, NULL, NULL); + free(wait_set); + goto pfail; + } + wait_set->key_comparator = (compare_func*)string_comparator; + wait_set->hasher = (hash_func*)string_hash; + } + + if (received.payload_size == length) + { + if (growalloc(old, received.payload, received.payload_size, char)) + { + if (wait_set != NULL) + hash_table_destroy(wait_set, NULL, NULL), free(wait_set); + return -1; + } + else + payload = received.payload; + } + + payload[length] = '\n'; + + fail_if ((errno = pthread_mutex_lock(®_mutex))); + + for (begin = 0; begin < length;) + { + char* end = rawmemchr(payload + begin, '\n'); + size_t len = (size_t)(end - payload) - begin - 1; + char* command = payload + begin; + + command[len] = '\0'; + begin += len + 1; + + if (registry_action_act(command, action, client, wait_set)) + goto fail_in_mutex; + } + + pthread_mutex_unlock(®_mutex); + + if (action == 0) + { + /* FIXME */ + } + + return 0; + + + pfail: + perror(*argv); + return -1; + fail_in_mutex: + pthread_mutex_unlock(®_mutex); + return -1; +} + + +/** + * Send a list of all registered commands to a client + * + * @param recv_client_id The ID of the client + * @param recv_message_id The ID of the received message + * @return Zero on success -1 on error or interruption, + * errno will be set accordingly + */ +int list_registry(const char* recv_client_id, const char* recv_message_id) +{ + size_t ptr = 0, i; + hash_entry_t* entry; + + if (send_buffer_size == 0) + { + fail_if (xmalloc(send_buffer, 256, char)); + send_buffer_size = 256; + } + + fail_if ((errno = pthread_mutex_lock(®_mutex))); + + foreach_hash_table_entry (reg_table, i, entry) + { + size_t key = entry->key; + char* command = (char*)(void*)key; + size_t len = strlen(command); + + while (ptr + len + 1 >= send_buffer_size) + if (growalloc(old, send_buffer, send_buffer_size, char)) + goto fail_in_mutex; + + memcpy(send_buffer + ptr, command, len * sizeof(char)); + ptr += len; + send_buffer[ptr++] = '\n'; + } + + i = strlen(recv_message_id) + strlen(recv_client_id) + 10 + 19; + i += strlen("To: %s\nIn response to: %s\nMessage ID: %" PRIi32 "\nLength: %" PRIu64 "\n\n"); + + while (ptr + i >= send_buffer_size) + { + if (growalloc(old, send_buffer, send_buffer_size, char)) + goto fail_in_mutex; + } + + sprintf(send_buffer + ptr, "To: %s\nIn response to: %s\nMessage ID: %" PRIi32 "\nLength: %" PRIu64 "\n\n", + recv_message_id, recv_client_id, message_id, ptr); + + message_id = message_id == INT32_MAX ? 0 : (message_id + 1); + + pthread_mutex_unlock(®_mutex); + + if (full_send(send_buffer + ptr, strlen(send_buffer + ptr))) + return 1; + return full_send(send_buffer, ptr); + + + fail_in_mutex: + pthread_mutex_unlock(®_mutex); + return -1; + + pfail: + perror(*argv); + return -1; +} + + +/** + * Free a key from a table + * + * @param obj The key + */ +void reg_table_free_key(size_t obj) +{ + char* command = (char*)(void*)obj; + free(command); +} + + +/** + * Free a value from a table + * + * @param obj The value + */ +void reg_table_free_value(size_t obj) +{ + client_list_t* list = (client_list_t*)(void*)obj; + client_list_destroy(list); + free(list); +} + + +/** + * Send a full message even if interrupted + * + * @param message The message to send + * @param length The length of the message + * @return Non-zero on success + */ +int full_send(const char* message, size_t length) +{ + size_t sent; + + while (length > 0) + { + sent = send_message(socket_fd, message, length); + if (sent > length) + { + eprint("Sent more of a message than exists in the message, aborting."); + return -1; + } + else if ((sent < length) && (errno != EINTR)) + { + perror(*argv); + return -1; + } + message += sent; + length -= sent; + } + return 0; +} + diff --git a/src/mds-registry/mds-registry.h b/src/mds-registry/mds-registry.h new file mode 100644 index 0000000..6f9355d --- /dev/null +++ b/src/mds-registry/mds-registry.h @@ -0,0 +1,91 @@ +/** + * mds — A micro-display server + * Copyright © 2014 Mattias Andrée (maandree@member.fsf.org) + * + * This program is free software: you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation, either version 3 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program. If not, see <http://www.gnu.org/licenses/>. + */ +#ifndef MDS_MDS_REGISTRY_H +#define MDS_MDS_REGISTRY_H + + +#include "../mds-base.h" + +#include <stdint.h> + + +/** + * Handle the received message + * + * @return Zero on success -1 on error or interruption, + * errno will be set accordingly + */ +int handle_message(void); + +/** + * Convert a client ID string into a client ID integer + * + * @param str The client ID string + * @return The client ID integer + */ +uint64_t parse_client_id(const char* str); + +/** + * Perform an action over the registry + * + * @param length The length of the received message + * @param action -1 to remove command, +1 to add commands, 0 to + * wait until the message commnds are registered + * @param recv_client_id The ID of the client + * @param recv_message_id The ID of the received message + * @return Zero on success -1 on error or interruption, + * errno will be set accordingly + */ +int registry_action(size_t length, int action, const char* recv_client_id, const char* recv_message_id); + +/** + * Send a list of all registered commands to a client + * + * @param recv_client_id The ID of the client + * @param recv_message_id The ID of the received message + * @return Zero on success -1 on error or interruption, + * errno will be set accordingly + */ +int list_registry(const char* recv_client_id, const char* recv_message_id); + +/** + * Free a key from a table + * + * @param obj The key + */ +void reg_table_free_key(size_t obj); + +/** + * Free a value from a table + * + * @param obj The value + */ +void reg_table_free_value(size_t obj); + +/** + * Send a full message even if interrupted + * + * @param message The message to send + * @param length The length of the message + * @return Non-zero on success + */ +int full_send(const char* message, size_t length); + + +#endif + |