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-rw-r--r--src/libmdsserver/config.h16
-rw-r--r--src/mds-vt.c371
-rw-r--r--src/mds-vt.h151
3 files changed, 538 insertions, 0 deletions
diff --git a/src/libmdsserver/config.h b/src/libmdsserver/config.h
index 3dd805c..4cc4fc3 100644
--- a/src/libmdsserver/config.h
+++ b/src/libmdsserver/config.h
@@ -60,6 +60,22 @@
/**
+ * The system's directory for pseudo-devices
+ */
+#ifndef DEVDIR
+#define DEVDIR "/dev"
+#endif
+
+
+/**
+ * Pathname pattern for virtual terminals
+ */
+#ifndef VT_PATH_PATTERN
+#define VT_PATH_PATTERN DEVDIR "/tty%i"
+#endif
+
+
+/**
* The root directory of all runtime data stored by MDS
*/
#ifndef MDS_RUNTIME_ROOT_DIRECTORY
diff --git a/src/mds-vt.c b/src/mds-vt.c
new file mode 100644
index 0000000..2167fb1
--- /dev/null
+++ b/src/mds-vt.c
@@ -0,0 +1,371 @@
+/**
+ * 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-vt.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 <sys/ioctl.h>
+#include <linux/kd.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <unistd.h>
+#include <signal.h>
+#define reconnect_to_display() -1 /* TODO */
+
+
+
+#define MDS_VT_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 = 1, /* we want to open the new tty (the rest is fine without root for some reason) */
+ .require_display = 1,
+ .require_respawn_info = 0,
+ .sanity_check_argc = 1,
+ .fork_for_safety = 0,
+ .danger_is_deadly = 0
+ };
+
+
+
+/**
+ * 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;
+
+
+
+/**
+ * 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)
+{
+ const char* const message =
+ "Command: intercept\n"
+ "Message ID: 0\n"
+ "Length: 14\n"
+ "\n"
+ "Command: echo\n";
+
+ if (full_send(message, strlen(message)))
+ return 1;
+ fail_if (server_initialised() < 0);
+ fail_if (mds_message_initialise(&received));
+
+ return 0;
+ pfail:
+ xperror(*argv);
+ mds_message_destroy(&received);
+ 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)
+{
+ return 2 * sizeof(int) + sizeof(int32_t) + mds_message_marshal_size(&received);
+}
+
+
+/**
+ * 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)
+{
+ buf_set_next(state_buf, int, MDS_VT_VARS_VERSION);
+ buf_set_next(state_buf, int, connected);
+ buf_set_next(state_buf, int32_t, message_id);
+ mds_message_marshal(&received, state_buf);
+
+ 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)
+{
+ int r;
+ /* buf_get_next(state_buf, int, MDS_VT_VARS_VERSION); */
+ buf_next(state_buf, int, 1);
+ buf_get_next(state_buf, int, connected);
+ buf_get_next(state_buf, int32_t, message_id);
+ r = mds_message_unmarshal(&received, state_buf);
+ if (r)
+ {
+ xperror(*argv);
+ mds_message_destroy(&received);
+ }
+ return r;
+}
+
+
+/**
+ * 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;
+
+ 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)
+ mds_message_destroy(&received);
+ 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;
+}
+
+
+/**
+ * Get the index of the next available virtual terminal
+ *
+ * @return -1 on error, 0 if the terminals are exhausted, otherwise the next terminal
+ */
+int vt_get_next_available(void)
+{
+ int next_vt = -1;
+ int r = ioctl(STDIN_FILENO, VT_OPENQRY, &next_vt);
+ if (r < 0)
+ return r;
+ return ((next_vt < 0) || (MAX_NR_CONSOLES < next_vt)) ? 0 : next_vt;
+}
+
+
+/**
+ * Get the currently active virtual terminal
+ *
+ * @return -1 on error, otherwise the current terminal
+ */
+int vt_get_active(void)
+{
+ struct vt_stat state;
+ if (ioctl(STDIN_FILENO, VT_GETSTATE, &state) < 0)
+ return -1;
+ return state.v_active;
+}
+
+
+/**
+ * Change currently active virtual terminal and wait for it to complete the switch
+ *
+ * @param vt The index of the terminal
+ * @return Zero on success, -1 on error
+ */
+int vt_set_active(int vt)
+{
+ if (ioctl(STDIN_FILENO, VT_ACTIVATE, vt) < 0)
+ return -1;
+
+ if (ioctl(STDIN_FILENO, VT_WAITACTIVE, vt) < 0)
+ xperror(*argv);
+
+ return 0;
+}
+
+
+/**
+ * Open a virtual terminal
+ *
+ * @param vt The index of the terminal
+ * @return The file descriptor for the terminal, -1 on error
+ */
+int vt_open(int vt)
+{
+ char vtpath[64]; /* Should be small enought and large enought for any
+ lunatic alternative to /dev/ttyNNN, if not you
+ will need to apply a patch (or fix your system.) */
+ sprintf(vtpath, VT_PATH_PATTERN, vt);
+ return open(vtpath, O_RDWR);
+}
+
+
+/**
+ * Construct a virtual terminal mode that can be used in `vt_get_set_mode`
+ *
+ * @param vt_switch_control Whether we want to be able to block and delay VT switches
+ * @param vt_leave_signal The signal that should be send to us we a process is trying
+ * to switch terminal to another terminal
+ * @param vt_enter_signal The signal that should be send to us we a process is trying
+ * to switch terminal to our terminal
+ * @param mode Output parameter
+ */
+void vt_construct_mode(int vt_switch_control, int vt_leave_signal,
+ int vt_enter_signal, struct vt_mode* restrict mode)
+{
+ mode->mode = vt_switch_control ? VT_PROCESS : VT_AUTO;
+ mode->waitv = 0;
+ mode->relsig = (short int)vt_leave_signal;
+ mode->acqsig = (short int)vt_enter_signal;
+}
+
diff --git a/src/mds-vt.h b/src/mds-vt.h
new file mode 100644
index 0000000..1f87726
--- /dev/null
+++ b/src/mds-vt.h
@@ -0,0 +1,151 @@
+/**
+ * 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/>.
+ */
+#ifndef MDS_MDS_VT_H
+#define MDS_MDS_VT_H
+
+
+#include "mds-base.h"
+
+#include <linux/vt.h>
+
+
+/**
+ * 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);
+
+
+/**
+ * Get the index of the next available virtual terminal
+ *
+ * @return -1 on error, 0 if the terminals are exhausted, otherwise the next terminal
+ */
+int vt_get_next_available(void);
+
+
+/**
+ * Get the currently active virtual terminal
+ *
+ * @return -1 on error, otherwise the current terminal
+ */
+int vt_get_active(void);
+
+
+/**
+ * Change currently active virtual terminal and wait for it to complete the switch
+ *
+ * @param vt The index of the terminal
+ * @return Zero on success, -1 on error
+ */
+int vt_set_active(int vt);
+
+
+/**
+ * Open a virtual terminal
+ *
+ * @param vt The index of the terminal
+ * @return The file descriptor for the terminal, -1 on error
+ */
+int vt_open(int vt);
+
+
+
+/**
+ * Block or stop blocking other programs to open the a terminal
+ *
+ * @param fd:int File descriptor for the terminal
+ * @param exclusive:int Whether to block other programs for using the terminal
+ * @return :int Zero on success, -1 on error
+ */
+#define vt_set_exclusive(fd, exclusive) \
+ (ioctl(fd, (exclusive) ? TIOCEXCL : TIOCNXCL))
+
+
+/**
+ * Configure a terminal to be set to either graphical mode or text mode
+ *
+ * @param fd:int File descriptor for the terminal
+ * @param graphical:int Whether to use graphical mode
+ * @return :int Zero on success, -1 on error
+ */
+#define vt_set_graphical(fd, graphical) \
+ (ioctl(fd, KDSETMODE, (graphical) ? KD_GRAPHICS : KD_TEXT))
+
+
+/**
+ * Construct a virtual terminal mode that can be used in `vt_get_set_mode`
+ *
+ * @param vt_switch_control Whether we want to be able to block and delay VT switches
+ * @param vt_leave_signal The signal that should be send to us we a process is trying
+ * to switch terminal to another terminal
+ * @param vt_enter_signal The signal that should be send to us we a process is trying
+ * to switch terminal to our terminal
+ * @param mode Output parameter
+ */
+void vt_construct_mode(int vt_switch_control, int vt_leave_signal,
+ int vt_enter_signal, struct vt_mode* restrict mode);
+
+
+/**
+ * Set or get the mode for a virtual terminal
+ *
+ * @param fd:int File descriptor for the terminal
+ * @param set:int Whether to set the mode
+ * @param mode:struct vt_mode* Input or outpur parameter for the mode
+ * @return :int Zero on success, -1 on error
+ */
+#define vt_get_set_mode(fd, set, mode) \
+ (ioctl(fd, set ? VT_SETMODE : VT_GETMODE, mode))
+
+
+/**
+ * Block or temporarily block virtual terminal switch
+ *
+ * @param fd:int File descriptor for our terminal
+ * @return :int Zero on success, -1 on error
+ */
+#define vt_stop_switch(fd) \
+ (ioctl(fd, VT_RELDISP, 0))
+
+
+/**
+ * Allow a temporarily block virtual terminal switch to continue
+ *
+ * @param fd:int File descriptor for our terminal
+ * @return :int Zero on success, -1 on error
+ */
+#define vt_continue_switch(fd) \
+ (ioctl(fd, VT_RELDISP, 1))
+
+
+/**
+ * Accept a virtual terminal switch
+ *
+ * @param fd:int File descriptor for our terminal
+ * @return :int Zero on success, -1 on error
+ */
+#define vt_accept_switch(fd) \
+ (ioctl(fd, VT_RELDISP, VT_ACKACQ))
+
+
+#endif
+
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