/**
* 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-clipboard.h"
#include <libmdsserver/macros.h>
#include <libmdsserver/util.h>
#include <libmdsserver/mds-message.h>
#include <errno.h>
#include <inttypes.h>
#include <string.h>
#include <stdio.h>
#include <stdlib.h>
#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];
/**
* 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;
const char* const message =
"Command: intercept\n"
"Message ID: 0\n"
"Length: 33\n"
"\n"
"Command: clipboard\n"
"Client closed\n";
if (full_send(message, strlen(message)))
return 1;
if (is_respawn)
{
const char* const crash_message =
"Command: clipboard-info\n"
"Event: crash\n"
"Message ID: 1\n"
"\n";
if (full_send(crash_message, strlen(crash_message)))
return 1;
message_id++;
}
fail_if (server_initialised() < 0);
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;
pfail:
xperror(*argv);
mds_message_destroy(&received);
while (--i >= 0)
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;
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, j, rc = 2 * sizeof(int) + sizeof(uint32_t) + mds_message_marshal_size(&received);
rc += 2 * CLIPBOARD_LEVELS * sizeof(size_t);
for (i = 0; i < CLIPBOARD_LEVELS; i++)
for (j = 0; j < clipboard_used[i]; j++)
{
clipitem_t 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;
}
/**
* Wipe a memory area and free it
*
* @param s The memory area
* @param n The number of bytes to write
*/
static inline __attribute__((optimize("-O0"))) void wipe_and_free(void* s, size_t n)
{
if (s != NULL)
free(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;
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++)
{
clipitem_t 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++)
{
clipitem_t 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;
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++)
{
clipitem_t* 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 (xmalloc(clip->content, clip->length, char));
memcpy(clip->content, state_buf, clip->length * sizeof(char));
state_buf += clip->length;
}
}
return 0;
pfail:
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 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:
xperror(*argv);
fail:
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;
}
/**
* 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))
{
xperror(*argv);
return -1;
}
message += sent;
length -= sent;
}
return 0;
}
/**
* 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) \
(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 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 == NULL)
{
eprint("received message with ID, ignoring, master server is misbehaving.");
return 0;
}
if (recv_client_closed)
{
if (strequals(recv_client_closed, "0:0"))
return 0;
return clipboard_death(recv_client_closed);
}
if (recv_action == NULL)
{
eprint("received message without any action, ignoring.");
return 0;
}
if (recv_level == NULL)
{
eprint("received message without specified clipboard level, ignoring.");
return 0;
}
level = atoi(recv_level);
if ((level < 0) || (CLIPBOARD_LEVELS <= level))
{
eprint("received message without invalid clipboard level, ignoring.");
return 0;
}
if (strequals(recv_client_id, "0:0"))
if (strequals(recv_action, "read") || strequals(recv_action, "get-size"))
{
eprint("received information request from an anonymous client, ignoring.");
return 0;
}
if (strequals(recv_action, "add"))
{
if (recv_length == NULL)
{
eprint("received request for adding a clipboard entry but did not receive any content, ignoring.");
return 0;
}
if ((strequals(recv_client_id, "0:0")) && startswith(recv_time_to_live, "until-death"))
{
eprint("received request new clipboard entry with autopurge upon"
" client close from an anonymous client, ignoring.");
return 0;
}
return clipboard_add(level, recv_time_to_live, recv_client_id);
}
else if (strequals(recv_action, "read"))
return clipboard_read(level, atoz(recv_index), recv_client_id, recv_message_id);
else if (strequals(recv_action, "clear"))
return clipboard_clear(level);
else if (strequals(recv_action, "set-size"))
{
if (recv_size == NULL)
{
eprint("received request for clipboard resizing without a new size, ignoring.");
return 0;
}
return clipboard_set_size(level, atoz(recv_size));
}
else if (strequals(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 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];
size_t n = 10 + 3 * (3 * sizeof(size_t) + sizeof(int));
char* message;
n += strlen("Command: clipboard-info\n"
"Event: crash\n"
"Message ID: %" PRIu32 "\n"
"Level: %i\n"
"Popped: %zu\n"
"Size: %zu\n"
"Used: %zu\n"
"\n");
if (xmalloc(message, n, char))
return -1;
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);
return full_send(message, strlen(message)) ? -1 : 0;
}
/**
* 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;
size_t i;
fail_if (monotone(&now));
for (i = 0; i < clipboard_used[level]; i++)
{
clipitem_t* 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;
pfail:
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++)
if (clipboard_purge(i, NULL))
return -1;
return 0;
}
/**
* 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++)
if (clipboard_purge(i, recv_client_id))
return -1;
return 0;
}
/**
* 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 = recv_client_id ? parse_client_id(recv_client_id) : 0;
clipitem_t new_clip;
if (clipboard_purge(level, NULL))
return -1;
if (strequals(time_to_live, "forever"))
autopurge = CLIPITEM_AUTOPURGE_NEVER;
else if (strequals(time_to_live, "until-death"))
autopurge = CLIPITEM_AUTOPURGE_UPON_DEATH;
else if (startswith(time_to_live, "until-death "))
{
autopurge = CLIPITEM_AUTOPURGE_UPON_DEATH_OR_CLOCK;
time_to_live += strlen("until-death ");
}
if ((autopurge & CLIPITEM_AUTOPURGE_UPON_CLOCK))
{
struct timespec dethklok;
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 (xmalloc(new_clip.content, new_clip.length, char));
memcpy(new_clip.content, received.payload, new_clip.length * sizeof(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;
pfail:
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;
if (clipboard_purge(level, NULL))
return -1;
if (clipboard_used[level] == 0)
{
n = strlen("To: %s\n"
"In response to: %s\n"
"Message ID: %" PRIu32 "\n"
"\n");
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"
"\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 = strlen("To: %s\n"
"In response to: %s\n"
"Message ID: %" PRIu32 "\n"
"Length: %zu\n"
"\n");
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"
"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 != NULL)
fail_if (full_send(clip->content, clip->length));
free(message);
return 0;
pfail:
xperror(*argv);
return -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;
if (clipboard_purge(level, NULL))
return -1;
if (size < clipboard_size[level])
{
size_t 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])
{
clipitem_t* old = clipboard[level];
if (xrealloc(clipboard[level], size, clipitem_t))
{
clipboard[level] = old;
goto pfail;
}
clipboard_size[level] = size;
}
return 0;
pfail:
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;
if (clipboard_purge(level, NULL))
return -1;
n = strlen("To: %s\n"
"In response to: %s\n"
"Message ID: %" PRIu32 "\n"
"Size: %zu\n"
"Used: %zu\n"
"\n");
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"
"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;
pfail:
xperror(*argv);
free(message);
return -1;
}
