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Diffstat (limited to '')
| -rw-r--r-- | src/mds-registry/reexec.c | 180 |
1 files changed, 180 insertions, 0 deletions
diff --git a/src/mds-registry/reexec.c b/src/mds-registry/reexec.c new file mode 100644 index 0000000..dafbff1 --- /dev/null +++ b/src/mds-registry/reexec.c @@ -0,0 +1,180 @@ +/** + * 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 "reexec.h" + +#include "util.h" +#include "globals.h" + +#include <libmdsserver/macros.h> +#include <libmdsserver/hash-help.h> +#include <libmdsserver/client-list.h> + +#include <stddef.h> +#include <stdlib.h> +#include <string.h> +#include <errno.h> + + + +/** + * 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; +} + |