/**
* 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;
}