/**
* 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>
#include <time.h>
#define reconnect_to_display() -1 /* TODO */
#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
};
/**
* Delete entry only when needed
*/
#define CLIPITEM_AUTOPURGE_NEVER 0
/**
* Delete entry when the client closes, or needed
*/
#define CLIPITEM_AUTOPURGE_UPON_DEATH 1
/**
* Delete entry when a point in time has elapsed, or needed
*/
#define CLIPITEM_AUTOPURGE_UPON_CLOCK 2
/**
* A clipboard entry
*/
typedef struct clipitem
{
/**
* The stored content
*/
char* content;
/**
* The length of the stored content
*/
size_t length;
/**
* Time of planned death if `autopurge` is `CLIPITEM_AUTOPURGE_UPON_CLOCK`
*/
struct timespec dethklok;
/**
* The client that issued the inclusion of this entry
*/
uint64_t client;
/**
* Rule for automatic deletion
*/
int autopurge;
} clipitem_t;
/**
* The number of levels in the clipboard
*/
#define CLIPBOARD_LEVELS 3
/**
* Value of the ‘Message ID’ header for the next message
*/
static int32_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: 19\n"
"\n"
"Command: clipboard\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++;
}
server_initialised();
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(int32_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, int32_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, int32_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;
size_t i, j;
while (!reexecing && !terminating)
{
int r = mds_message_read(&received, socket_fd);
if (r == 0)
{
r = 0; /* FIXME */
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:
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;
}
