/** * mds — A micro-display server * Copyright © 2014, 2015, 2016, 2017 Mattias Andrée (m@maandree.se) * * 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 . */ #include "mds-clipboard.h" #include #include #include #include #include #include #include #include #define reconnect_to_display() -1 #define MDS_CLIPBOARD_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 = 1, .sanity_check_argc = 1, .fork_for_safety = 0, .danger_is_deadly = 1 }; /** * Value of the ‘Message ID’ header for the next message */ static uint32_t message_id = 1; /** * Buffer for received messages */ static mds_message_t received; /** * Whether the server is connected to the display */ static int connected = 1; /** * The size of each clipstack */ static size_t clipboard_size[CLIPBOARD_LEVELS] = { 10, 1, 1 }; /** * The number of used elements in each clipstack */ static size_t clipboard_used[CLIPBOARD_LEVELS] = { 0, 0, 0 }; /** * The entries in each clipstack */ static clipitem_t *clipboard[CLIPBOARD_LEVELS]; /** * Send a full message even if interrupted * * @param message:const char* The message to send * @param length:size_t The length of the message * @return :int Zero on success, -1 on error */ #define full_send(message, length)\ ((full_send)(socket_fd, message, length)) /** * 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) { 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) { ssize_t i = 0; int stage = 0; const char* const message = "Command: intercept\n" "Message ID: 0\n" "Length: 33\n" "\n" "Command: clipboard\n" "Client closed\n"; fail_if (full_send(message, strlen(message))); if (is_respawn) { const char* const crash_message = "Command: clipboard-info\n" "Event: crash\n" "Message ID: 1\n" "\n"; fail_if (full_send(crash_message, strlen(crash_message))); message_id++; } stage++; fail_if (server_initialised() < 0); stage++; fail_if (mds_message_initialise(&received)); for (i = 0; i < CLIPBOARD_LEVELS; i++) fail_if (xcalloc(clipboard[i], clipboard_size[i], clipitem_t)); return 0; fail: xperror(*argv); if (stage == 0) return 1; mds_message_destroy(&received); if (stage == 1) return 1; while (i--) free(clipboard[i]); return 1; } /** * 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; fail_if (reconnect_to_display()); connected = 1; return 0; fail: mds_message_destroy(&received); return 1; } /** * 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, j, rc = 2 * sizeof(int) + sizeof(uint32_t) + mds_message_marshal_size(&received); clipitem_t clip; rc += 2 * CLIPBOARD_LEVELS * sizeof(size_t); for (i = 0; i < CLIPBOARD_LEVELS; i++) { for (j = 0; j < clipboard_used[i]; j++) { clip = clipboard[i][j]; rc += sizeof(size_t) + sizeof(time_t) + sizeof(long) + sizeof(uint64_t) + sizeof(int); rc += clip.length * sizeof(char); } } return rc; } /** * `memset`, but the compiler does not know that */ void *(*volatile mds_clipboard_my_explicit_memset)(void *s, int c, size_t n) = memset; /** * Wipe a memory area and free it * * @param s The memory area * @param n The number of bytes to write */ static inline void wipe_and_free(void *s, size_t n) { if (s) free(mds_clipboard_my_explicit_memset(s, 0, n)); } /** * 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, j; clipitem_t clip; buf_set_next(state_buf, int, MDS_CLIPBOARD_VARS_VERSION); buf_set_next(state_buf, int, connected); buf_set_next(state_buf, uint32_t, message_id); mds_message_marshal(&received, state_buf); /* Removed entires from the clipboard that may not be marshalled. */ for (i = 0; i < CLIPBOARD_LEVELS; i++) { for (j = 0; j < clipboard_used[i]; j++) { clip = clipboard[i][j]; if (clip.autopurge == CLIPITEM_AUTOPURGE_NEVER) continue; wipe_and_free(clip.content, clip.length * sizeof(char)); memmove(clipboard[i] + j, clipboard[i] + j + 1, (clipboard_used[i] - j - 1) * sizeof(clipitem_t)); clipboard_used[i]--; j--; } } /* Marshal clipboard. */ for (i = 0; i < CLIPBOARD_LEVELS; i++) { buf_set_next(state_buf, size_t, clipboard_size[i]); buf_set_next(state_buf, size_t, clipboard_used[i]); for (j = 0; j < clipboard_used[i]; j++) { clip = clipboard[i][j]; buf_set_next(state_buf, size_t, clip.length); buf_set_next(state_buf, time_t, clip.dethklok.tv_sec); buf_set_next(state_buf, long, clip.dethklok.tv_nsec); buf_set_next(state_buf, uint64_t, clip.client); buf_set_next(state_buf, int, clip.autopurge); memcpy(state_buf, clip.content, clip.length * sizeof(char)); state_buf += clip.length; free(clip.content); } free(clipboard[i]); } 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) { size_t i, j; clipitem_t *clip; for (i = 0; i < CLIPBOARD_LEVELS; i++) clipboard[i] = NULL; /* buf_get_next(state_buf, int, MDS_CLIPBOARD_VARS_VERSION); */ buf_next(state_buf, int, 1); buf_get_next(state_buf, int, connected); buf_get_next(state_buf, uint32_t, message_id); fail_if (mds_message_unmarshal(&received, state_buf)); for (i = 0; i < CLIPBOARD_LEVELS; i++) { buf_get_next(state_buf, size_t, clipboard_size[i]); buf_get_next(state_buf, size_t, clipboard_used[i]); fail_if (xcalloc(clipboard[i], clipboard_size[i], clipitem_t)); for (j = 0; j < clipboard_used[i]; j++) { clip = clipboard[i] + j; buf_get_next(state_buf, size_t, clip->length); buf_get_next(state_buf, time_t, clip->dethklok.tv_sec); buf_get_next(state_buf, long, clip->dethklok.tv_nsec); buf_get_next(state_buf, uint64_t, clip->client); buf_get_next(state_buf, int, clip->autopurge); fail_if (xmemdup(clip->content, state_buf, clip->length, char)); state_buf += clip->length; } } return 0; fail: xperror(*argv); mds_message_destroy(&received); for (i = 0; i < CLIPBOARD_LEVELS; i++) { if (clipboard[i] != NULL) { for (j = 0; j < clipboard_used[i]; j++) free(clipboard[i][j].content); free(clipboard[i]); } } 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, r; size_t i, j; while (!reexecing && !terminating) { if (danger) { danger = 0; clipboard_danger(); } if (r = mds_message_read(&received, socket_fd), r == 0) if (r = handle_message(), r == 0) continue; if (r == -2) { eprint("corrupt message received, aborting."); goto done; } else if (errno == EINTR) { continue; } else { fail_if (errno != ECONNRESET); } eprint("lost connection to server."); mds_message_destroy(&received); mds_message_initialise(&received); connected = 0; fail_if (reconnect_to_display()); connected = 1; } rc = 0; goto done; fail: xperror(*argv); done: if (!rc && reexecing) return 0; mds_message_destroy(&received); for (i = 0; i < CLIPBOARD_LEVELS; i++) { if (clipboard[i] != NULL) { for (j = 0; j < clipboard_used[i]; j++) wipe_and_free(clipboard[i][j].content, clipboard[i][j].length); free(clipboard[i]); } } return rc; } /** * Handle the received message * * @return Zero on success, -1 on error */ int handle_message(void) { /* Fetch message headers. */ const char *recv_client_id = "0:0"; const char *recv_message_id = NULL; const char *recv_length = NULL; const char *recv_level = NULL; const char *recv_action = NULL; const char *recv_size = NULL; const char *recv_index = "0"; const char *recv_time_to_live = "forever"; const char *recv_client_closed = NULL; size_t i; int level; #define __get_header(storage, header)\ (strstarts(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 if __get_header(recv_level, "Level: "); else if __get_header(recv_size, "Size: "); else if __get_header(recv_index, "Index: "); else if __get_header(recv_time_to_live, "Time to live: "); else if __get_header(recv_client_closed, "Client closed: "); } #undef __get_header /* Validate headers and take appropriate action. */ if (!recv_message_id) return eprint("received message without ID, ignoring, master server is misbehaving."), 0; if (recv_client_closed) { if (streq(recv_client_closed, "0:0")) return 0; return clipboard_death(recv_client_closed); } if (!recv_action) return eprint("received message without any action, ignoring."), 0; if (!recv_level) return eprint("received message without specified clipboard level, ignoring."), 0; level = atoi(recv_level); if ((level < 0) || (CLIPBOARD_LEVELS <= level)) return eprint("received message without invalid clipboard level, ignoring."), 0; if (streq(recv_client_id, "0:0")) if (streq(recv_action, "read") || streq(recv_action, "get-size")) return eprint("received information request from an anonymous client, ignoring."), 0; if (streq(recv_action, "add")) { if (recv_length == NULL) return eprint("received request for adding a clipboard entry " "but did not receive any content, ignoring."), 0; if ((streq(recv_client_id, "0:0")) && strstarts(recv_time_to_live, "until-death")) return eprint("received request new clipboard entry with autopurge upon " "client close from an anonymous client, ignoring."), 0; return clipboard_add(level, recv_time_to_live, recv_client_id); } else if (streq(recv_action, "read")) { return clipboard_read(level, atoz(recv_index), recv_client_id, recv_message_id); } else if (streq(recv_action, "clear")) { return clipboard_clear(level); } else if (streq(recv_action, "set-size")) { if (recv_size == NULL) return eprint("received request for clipboard resizing without a new size, ignoring."), 0; return clipboard_set_size(level, atoz(recv_size)); } else if (streq(recv_action, "get-size")) { return clipboard_get_size(level, recv_client_id, recv_message_id); } eprint("received message with invalid action, ignoring."); return 0; } /** * Free an entry from the clipboard * * @param entry The clipboard entry to free */ static inline void __attribute__((nonnull)) free_clipboard_entry(clipitem_t *entry) { if (entry->autopurge == CLIPITEM_AUTOPURGE_NEVER) free(entry->content); else wipe_and_free(entry->content, entry->length); entry->content = NULL; } /** * Broadcast notification about an automatic removal of an entry * * @param level The clipboard level * @param index The index in the clipstack of the removed entry * @return Zero on success, -1 on error, `errno` will be set accordingly */ static int clipboard_notify_pop(int level, size_t index) { size_t size = clipboard_size[level]; size_t used = clipboard_used[level]; char message[10 + 3 * (sizeof(int) + 3 * sizeof(size_t)) + sizeof("Command: clipboard-info\n" "Event: crash\n" "Message ID: \n" "Level: \n" "Popped: \n" "Size: \n" "Used: \n" "\n") / sizeof(char)]; sprintf(message, "Command: clipboard-info\n" "Event: crash\n" "Message ID: %" PRIu32 "\n" "Level: %i\n" "Popped: %zu\n" "Size: %zu\n" "Used: %zu\n" "\n", message_id, level, index, size, used); message_id = message_id == UINT32_MAX ? 0 : (message_id + 1); fail_if (full_send(message, strlen(message)) ? -1 : 0); return 0; fail: return -1; } /** * Remove old entries from a clipstack * * @param level The clipboard level * @param client_id The ID of the client that has newly closed, `NULL` if none * @return Zero on success, -1 on error */ static int clipboard_purge(int level, const char *client_id) { uint64_t client = client_id ? parse_client_id(client_id) : 0; struct timespec now; clipitem_t *clip; size_t i; fail_if (monotone(&now)); for (i = 0; i < clipboard_used[level]; i++) { clip = clipboard[level] + i; if ((clip->autopurge & CLIPITEM_AUTOPURGE_UPON_DEATH)) { if (clip->client == client) goto removed; } if ((clip->autopurge & CLIPITEM_AUTOPURGE_UPON_CLOCK)) { if (clip->dethklok.tv_sec > now.tv_sec) goto removed; if (clip->dethklok.tv_sec == now.tv_sec) if (clip->dethklok.tv_nsec >= now.tv_nsec) goto removed; } continue; removed: free_clipboard_entry(clipboard[level] + i); clipboard_used[level]--; fail_if (clipboard_notify_pop(level, i)); memmove(clipboard[level] + i, clipboard[level] + i + 1, (clipboard_used[level] - i) * sizeof(clipitem_t)); i--; } return 0; fail: xperror(*argv); return -1; } /** * Remove expired entries * * @return Zero on success, -1 on error */ int clipboard_danger(void) { int i; for (i = 0; i < CLIPBOARD_LEVELS; i++) fail_if (clipboard_purge(i, NULL)); return 0; fail: return -1; } /** * Remove entries in the clipboard added by a client * * @param recv_client_id The ID of the client * @return Zero on success, -1 on error */ int clipboard_death(const char *recv_client_id) { int i; for (i = 0; i < CLIPBOARD_LEVELS; i++) fail_if (clipboard_purge(i, recv_client_id)); return 0; fail: return -1; } /** * Add a new entry to the clipboard * * @param level The clipboard level * @param time_to_live When the entry should be removed * @param recv_client_id The ID of the client * @return Zero on success, -1 on error */ int clipboard_add(int level, const char *time_to_live, const char *recv_client_id) { int autopurge = CLIPITEM_AUTOPURGE_UPON_CLOCK; uint64_t client = parse_client_id(recv_client_id); clipitem_t new_clip; struct timespec dethklok; fail_if (clipboard_purge(level, NULL)); if (streq(time_to_live, "forever")) { autopurge = CLIPITEM_AUTOPURGE_NEVER; } else if (streq(time_to_live, "until-death")) { autopurge = CLIPITEM_AUTOPURGE_UPON_DEATH; } else if (strstarts(time_to_live, "until-death ")) { autopurge = CLIPITEM_AUTOPURGE_UPON_DEATH_OR_CLOCK; time_to_live += strlen("until-death "); } if ((autopurge & CLIPITEM_AUTOPURGE_UPON_CLOCK)) { fail_if (monotone(&dethklok)); dethklok.tv_sec += (time_t)atoll(time_to_live); /* It should really be `atol`, but we want to be future-proof. */ new_clip.dethklok = dethklok; } else { new_clip.dethklok.tv_sec = 0; new_clip.dethklok.tv_nsec = 0; } new_clip.client = client; new_clip.autopurge = autopurge; new_clip.length = received.payload_size; fail_if (xmemdup(new_clip.content, received.payload, new_clip.length, char)); if (clipboard_used[level] == clipboard_size[level]) free_clipboard_entry(clipboard[level] + clipboard_used[level] - 1); memmove(clipboard[level] + 1, clipboard[level], (clipboard_used[level] - 1) * sizeof(clipitem_t)); clipboard[level][0] = new_clip; return 0; fail: xperror(*argv); return -1; } /** * Read an entry to the clipboard * * @param level The clipboard level * @param index The index of the clipstack element * @param recv_client_id The ID of the client * @param recv_message_id The message ID of the received message * @return Zero on success, -1 on error */ int clipboard_read(int level, size_t index, const char *recv_client_id, const char *recv_message_id) { char *message = NULL; clipitem_t *clip = NULL; size_t n; fail_if (clipboard_purge(level, NULL)); if (clipboard_used[level] == 0) { n = sizeof("To: \n" "In response to: \n" "Message ID: \n" "Origin command: clipboard\n" "\n") / sizeof(char); n += strlen(recv_client_id) + strlen(recv_message_id) + 10; fail_if (xmalloc(message, n, char)); sprintf(message, "To: %s\n" "In response to: %s\n" "Message ID: %" PRIu32 "\n" "Origin command: clipboard\n" "\n", recv_client_id, recv_message_id, message_id); goto send; } if (index >= clipboard_used[level]) index = clipboard_used[level] - 1; clip = clipboard[level] + index; n = sizeof("To: \n" "In response to: \n" "Message ID: \n" "Origin command: clipboard\n" "Length: \n" "\n") / sizeof(char); n += strlen(recv_client_id) + strlen(recv_message_id) + 10 + 3 * sizeof(size_t); fail_if (xmalloc(message, n, char)); sprintf(message, "To: %s\n" "In response to: %s\n" "Message ID: %" PRIu32 "\n" "Origin command: clipboard\n" "Length: %zu\n" "\n", recv_client_id, recv_message_id, message_id, clip->length); send: message_id = message_id == INT32_MAX ? 0 : (message_id + 1); fail_if (full_send(message, strlen(message))); if (clip) fail_if (full_send(clip->content, clip->length)); free(message); return 0; fail: xperror(*argv); free(message); return errno = 0, -1; } /** * Clear a clipstack * * @param level The clipboard level * @return Zero on success, -1 on error */ int clipboard_clear(int level) { size_t i; for (i = 0; i < clipboard_used[level]; i++) free_clipboard_entry(clipboard[level] + i); clipboard_used[level] = 0; return 0; } /** * Resize a clipstack * * @param level The clipboard level * @param size The new clipstack size * @return Zero on success, -1 on error */ int clipboard_set_size(int level, size_t size) { size_t i, old_used; clipitem_t* old; fail_if (clipboard_purge(level, NULL)); if (size < clipboard_size[level]) { old_used = clipboard_used[level]; if (size < old_used) { clipboard_used[level] = size; for (i = size; i < old_used; i++) free_clipboard_entry(clipboard[level] + i); } } if (size != clipboard_size[level]) { old = clipboard[level]; if (xrealloc(clipboard[level], size, clipitem_t)) { clipboard[level] = old; fail_if (1); } clipboard_size[level] = size; } return 0; fail: xperror(*argv); return -1; } /** * Get the size of a clipstack and how many entries it contains * * @param level The clipboard level * @param recv_client_id The ID of the client * @param recv_message_id The message ID of the received message * @return Zero on success, -1 on error */ int clipboard_get_size(int level, const char *recv_client_id, const char *recv_message_id) { char *message = NULL; size_t n; fail_if (clipboard_purge(level, NULL)); n = sizeof("To: \n" "In response to: \n" "Message ID: \n" "Origin command: clipboard\n" "Size: \n" "Used: \n" "\n") / sizeof(char); n += strlen(recv_client_id) + strlen(recv_message_id) + 10 + 2 * 3 * sizeof(size_t); fail_if (xmalloc(message, n, char)); sprintf(message, "To: %s\n" "In response to: %s\n" "Message ID: %" PRIu32 "\n" "Origin command: clipboard\n" "Size: %zu\n" "Used: %zu\n" "\n", recv_client_id, recv_message_id, message_id, clipboard_size[level], clipboard_used[level]); message_id = message_id == INT32_MAX ? 0 : (message_id + 1); fail_if (full_send(message, strlen(message))); free(message); return 0; fail: xperror(*argv); free(message); return errno = 0, -1; } /** * This function is called when a signal that * signals that the system to dump state information * and statistics has been received * * @param signo The signal that has been received */ void received_info(int signo) { SIGHANDLER_START; clipitem_t clipitem; size_t i, j, n; struct timespec now; if (monotone(&now) < 0) iprint("(unable to get current time)"); else iprintf("current time: %ji.%09li", (intmax_t)(now.tv_sec), (long)(now.tv_nsec)); iprintf("next message ID: %" PRIu32, message_id); iprintf("connected: %s", connected ? "yes" : "no"); for (i = 0; i < CLIPBOARD_LEVELS; i++) { n = clipboard_used[i]; iprintf("clipstack %zu: allocated: %zu", i, clipboard_size[i]); iprintf("clipstack %zu: used: %zu", i, n); for (j = 0; j < n; j++) { clipitem = clipboard[i][j]; iprintf("clipstack %zu: item %zu:", i, j); iprintf(" autopurge: %s", clipitem.autopurge == CLIPITEM_AUTOPURGE_NEVER ? "as needed" : clipitem.autopurge == CLIPITEM_AUTOPURGE_UPON_DEATH ? "upon death or as needed" : clipitem.autopurge == CLIPITEM_AUTOPURGE_UPON_CLOCK ? "timeout or as needed" : clipitem.autopurge == CLIPITEM_AUTOPURGE_UPON_DEATH_OR_CLOCK ? "upon death, timeout or as needed" : "unrecognised rule, something is wrong here!"); iprintf(" client: %" PRIu32 ":%" PRIu32, (uint32_t)(clipitem.client >> 32), (uint32_t)(clipitem.client)); if (clipitem.autopurge & CLIPITEM_AUTOPURGE_UPON_CLOCK) iprintf(" timeout: %ji.%09li", (intmax_t)(clipitem.dethklok.tv_sec), (long)(clipitem.dethklok.tv_nsec)); iprintf(" butes: %zu", clipitem.length); iprintf(" content (possibily truncated): %.*s", (int)strnlen(clipitem.content, clipitem.length > 50 ? (size_t)50 : clipitem.length), clipitem.content); } } SIGHANDLER_END; (void) signo; }