Merge branch 'signal' into 'master'

buffyboard: track virtual terminals with /sys/class/tty/tty0/active

Closes #32, #11, and #3

See merge request postmarketOS/buffybox!58

CHANGELOG.md

@@ -16,6 +16,8 @@ If a change only affects particular applications, they are listed in parentheses
 - fix: Do not hang if graphics backend is not available (!57, thanks @vstoiakin)
 - fix!(unl0kr): Disable software rotation due to regressed performance (!56)
 - feat(buffyboard): Rotate the keyboard according to /sys/class/graphics/fbcon/rotate by default (!60, thanks @vstoiakin)
+- fix(buffyboard): Prevent overlap of the keyboard and the terminal (!58, thanks @vstoiakin)
+- feat(buffyboard): Add a handler for SIGUSR1 to redraw the keyboard (!58, thanks @vstoiakin)
 
 ## 3.3.0 (2025-04-15)
 

buffyboard/buffyboard.conf

@@ -7,3 +7,4 @@ default=breezy-light
 
 #[quirks]
 #fbdev_force_refresh=true
+#ignore_unused_terminals=false

buffyboard/buffyboard.service.in

@@ -1,5 +1,6 @@
 [Unit]
 Documentation=https://gitlab.postmarketos.org/postmarketOS/buffybox
+After=getty.target
 
 [Service]
 ExecStart=@bindir@/buffyboard
@@ -36,3 +37,6 @@ SystemCallArchitectures=native
 SystemCallFilter=@system-service
 SystemCallFilter=~@privileged
 SystemCallFilter=~@resources
+
+[Install]
+WantedBy=multi-user.target

buffyboard/config.c

@@ -63,6 +63,10 @@ static int parsing_handler(void* user_data, const char* section, const char* key
             if (bbx_config_parse_bool(value, &(opts->quirks.fbdev_force_refresh))) {
                 return 1;
             }
+        } else if (strcmp(key, "ignore_unused_terminals") == 0) {
+            if (bbx_config_parse_bool(value, &(opts->quirks.ignore_unused_terminals))) {
+                return 1;
+            }
         }
     }
 
@@ -80,6 +84,7 @@ void bb_config_init_opts(bb_config_opts *opts) {
     opts->input.pointer = true;
     opts->input.touchscreen = true;
     opts->quirks.fbdev_force_refresh = false;
+    opts->quirks.ignore_unused_terminals = true;
 }
 
 void bb_config_parse_directory(const char *path, bb_config_opts *opts) {

buffyboard/config.h

@@ -35,6 +35,8 @@ typedef struct {
 typedef struct {
     /* If true and using the framebuffer backend, force a refresh on every draw operation */
     bool fbdev_force_refresh;
+    /* If true, do not automatically update the layout of new terminals and wait for SIGUSR1 */
+    bool ignore_unused_terminals;
 } bb_config_opts_quirks;
 
 /**

buffyboard/getty-buffyboard.conf

@@ -0,0 +1,3 @@
+[Service]
+ExecStartPost=-/usr/bin/kill -s SIGUSR1 buffyboard
+StandardError=journal

buffyboard/main.c

@@ -19,13 +19,14 @@
 #include "../shared/themes.h"
 #include "../squeek2lvgl/sq2lv.h"
 
-#include <limits.h>
+#include <sys/epoll.h>
+#include <errno.h>
+#include <fcntl.h>
 #include <signal.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <unistd.h>
 
-#include <sys/time.h>
 
 
 /**
@@ -35,37 +36,19 @@
 bb_cli_opts cli_opts;
 bb_config_opts conf_opts;
 
-static bool resize_terminals = false;
 static lv_obj_t *keyboard = NULL;
-
+static sig_atomic_t redraw_requested = false;
 
 /**
  * Static prototypes
  */
 
 /**
- * Compute the denominator of the keyboard height factor. The keyboard height is calculated
+ * Handle signals sent to the process.
- * by dividing the display height by the denominator.
- *
- * @param width display width
- * @param height display height
- * @return denominator
- */
-static int keyboard_height_denominator(int32_t width, int32_t height);
-
-/**
- * Handle termination signals sent to the process.
  *
  * @param signum the signal's number
  */
-static void sigaction_handler(int signum);
+static void signal_handler(int signum);
-
-/**
- * Callback for the terminal resizing timer.
- *
- * @param timer the timer object
- */
-static void terminal_resize_timer_cb(lv_timer_t *timer);
 
 /**
  * Handle LV_EVENT_VALUE_CHANGED events from the keyboard widget.
@@ -93,25 +76,16 @@ static void pop_checked_modifier_keys(void);
  * Static functions
  */
 
-static int keyboard_height_denominator(int32_t width, int32_t height) {
+static void signal_handler(int signum) {
-    return (height > width) ? 3 : 2;
+    if (signum == SIGUSR1) {
-}
+        redraw_requested = true;
-
+        return;
-static void sigaction_handler(int signum) {
-    LV_UNUSED(signum);
-    if (resize_terminals) {
-        bb_terminal_reset_all();
     }
+
+    bb_terminal_reset_all();
     exit(0);
 }
 
-static void terminal_resize_timer_cb(lv_timer_t *timer) {
-    LV_UNUSED(timer);
-    if (resize_terminals) {
-        bb_terminal_shrink_current();
-    }
-}
-
 static void keyboard_value_changed_cb(lv_event_t *event) {
     lv_obj_t *kb = lv_event_get_target(event);
 
@@ -196,23 +170,9 @@ int main(int argc, char *argv[]) {
     bb_config_parse_directory("/etc/buffyboard.conf.d", &conf_opts);
     bb_config_parse_files(cli_opts.config_files, cli_opts.num_config_files, &conf_opts);
 
-    /* Prepare for terminal resizing and reset */
-    resize_terminals = bb_terminal_init(2.0f / 3.0f);
-    if (resize_terminals) {
-        /* Clean up on termination */
-        struct sigaction action;
-        lv_memset(&action, 0, sizeof(action));
-        action.sa_handler = sigaction_handler;
-        sigaction(SIGINT, &action, NULL);
-        sigaction(SIGTERM, &action, NULL);
-
-        /* Resize current terminal */
-        bb_terminal_shrink_current();
-    }
-
     /* Set up uinput device */
     if (!bb_uinput_device_init(sq2lv_unique_scancodes, sq2lv_num_unique_scancodes)) {
-        return 1;
+        return EXIT_FAILURE;
     }
 
     /* Initialise LVGL and set up logging callback */
@@ -223,17 +183,19 @@ int main(int argc, char *argv[]) {
     lv_display_t *disp = lv_linux_fbdev_create();
     if (access("/dev/fb0", F_OK) != 0) {
         bbx_log(BBX_LOG_LEVEL_ERROR, "/dev/fb0 is not available");
-        sigaction_handler(SIGTERM);
+        return EXIT_FAILURE;
     }
     lv_linux_fbdev_set_file(disp, "/dev/fb0");
     if (conf_opts.quirks.fbdev_force_refresh) {
         lv_linux_fbdev_set_force_refresh(disp, true);
     }
+    lv_display_set_physical_resolution(disp,
+        lv_display_get_horizontal_resolution(disp),
+        lv_display_get_vertical_resolution(disp));
 
     /* Override display properties with command line options if necessary */
     lv_display_set_offset(disp, cli_opts.x_offset, cli_opts.y_offset);
-    if (cli_opts.hor_res > 0 || cli_opts.ver_res > 0) {
+    if (cli_opts.hor_res > 0 && cli_opts.ver_res > 0) {
-        lv_display_set_physical_resolution(disp, lv_display_get_horizontal_resolution(disp), lv_display_get_vertical_resolution(disp));
         lv_display_set_resolution(disp, cli_opts.hor_res, cli_opts.ver_res);
     }
     if (cli_opts.dpi > 0) {
@@ -241,27 +203,29 @@ int main(int argc, char *argv[]) {
     }
 
     /* Set up display rotation */
-    int32_t hor_res_phys = lv_display_get_horizontal_resolution(disp);
-    int32_t ver_res_phys = lv_display_get_vertical_resolution(disp);
-    lv_display_set_physical_resolution(disp, hor_res_phys, ver_res_phys);
     lv_display_set_rotation(disp, cli_opts.rotation);
+
+    const int32_t hor_res = lv_display_get_horizontal_resolution(disp);
+    const int32_t ver_res = lv_display_get_vertical_resolution(disp);
+    const int32_t keyboard_height = ver_res > hor_res ? ver_res / 3 : ver_res / 2;
+    const int32_t tty_height = ver_res - keyboard_height;
+
     switch (cli_opts.rotation) {
-        case LV_DISPLAY_ROTATION_0:
+    case LV_DISPLAY_ROTATION_0:
-        case LV_DISPLAY_ROTATION_180: {
+    case LV_DISPLAY_ROTATION_180:
-            int32_t denom = keyboard_height_denominator(hor_res_phys, ver_res_phys);
+        lv_display_set_resolution(disp, hor_res, keyboard_height);
-            lv_display_set_resolution(disp, hor_res_phys, ver_res_phys / denom);
+        lv_display_set_offset(disp, 0, cli_opts.rotation == LV_DISPLAY_ROTATION_0? tty_height : 0);
-            lv_display_set_offset(disp, 0, (cli_opts.rotation == LV_DISPLAY_ROTATION_0) ? (denom - 1) * ver_res_phys / denom : 0);
+        break;
-            break;
+    case LV_DISPLAY_ROTATION_90:
-        }
+    case LV_DISPLAY_ROTATION_270:
-        case LV_DISPLAY_ROTATION_90:
+        lv_display_set_resolution(disp, keyboard_height, hor_res);
-        case LV_DISPLAY_ROTATION_270: {
+        lv_display_set_offset(disp, cli_opts.rotation == LV_DISPLAY_ROTATION_90? tty_height : 0, 0);
-            int32_t denom = keyboard_height_denominator(ver_res_phys, hor_res_phys);
+        break;
-            lv_display_set_resolution(disp, hor_res_phys / denom, ver_res_phys);
-            lv_display_set_offset(disp, 0, (cli_opts.rotation == LV_DISPLAY_ROTATION_90) ? (denom - 1) * hor_res_phys / denom : 0);
-            break;
-        }
     }
 
+    /* Prepare for terminal resizing and reset */
+    bb_terminal_init(tty_height - 8, hor_res, ver_res);
+
     /* Start input device monitor and auto-connect available devices */
     bbx_indev_start_monitor_and_autoconnect(false, conf_opts.input.pointer, conf_opts.input.touchscreen);
 
@@ -286,13 +250,89 @@ int main(int argc, char *argv[]) {
     /* Apply default keyboard layout */
     sq2lv_switch_layout(keyboard, SQ2LV_LAYOUT_TERMINAL_US);
 
-    /* Start timer for periodically resizing terminals */
+    /* Open the file to track virtual terminals */
-    lv_timer_create(terminal_resize_timer_cb, 1000,  NULL);
+    int fd_tty = open("/sys/class/tty/tty0/active", O_RDONLY|O_NOCTTY|O_CLOEXEC);
+    if (fd_tty < 0) {
+        perror("Can't open /sys/class/tty/tty0/active");
+        return EXIT_FAILURE;
+    }
+
+    int fd_epoll = epoll_create1(EPOLL_CLOEXEC);
+    if (fd_epoll == -1) {
+        perror("epoll_create1() is failed");
+        return EXIT_FAILURE;
+    }
+
+    struct epoll_event event;
+    event.events = EPOLLIN|EPOLLET;
+    event.data.fd = fd_tty;
+
+    int r = epoll_ctl(fd_epoll, EPOLL_CTL_ADD, fd_tty, &event);
+    if (r == -1) {
+        perror("epoll_ctl() is failed");
+        return EXIT_FAILURE;
+    }
+
+    /* Set signal handlers */
+    struct sigaction action;
+    action.sa_handler = signal_handler;
+    action.sa_flags = 0;
+    sigfillset(&action.sa_mask);
+    sigaction(SIGINT, &action, NULL);
+    sigaction(SIGTERM, &action, NULL);
+
+    action.sa_flags = SA_RESTART;
+    sigemptyset(&action.sa_mask);
+    sigaction(SIGUSR1, &action, NULL);
+
+    sigset_t sigmask;
+    sigemptyset(&sigmask);
+    sigaddset(&sigmask, SIGUSR1);
+
+    sigprocmask(SIG_BLOCK, &sigmask, NULL);
+
+    sigemptyset(&sigmask);
 
     /* Periodically run timer / task handler */
     while(1) {
         uint32_t time_till_next = lv_timer_handler();
-        usleep(time_till_next * 1000);
+
+        int r = epoll_pwait(fd_epoll, &event, 1, time_till_next, &sigmask);
+        if (r == 0)
+            continue;
+        if (r < 0) {
+            if (errno != EINTR) {
+                perror("epoll_wait() is failed");
+                return EXIT_FAILURE;
+            }
+            if (!redraw_requested)
+                continue;
+            redraw_requested = false;
+        } else if (conf_opts.quirks.ignore_unused_terminals) {
+            lseek(fd_tty, 0, SEEK_SET);
+
+            char buffer[8];
+            ssize_t size = read(fd_tty, buffer, sizeof(buffer));
+            if (size <= 0) {
+                bbx_log(BBX_LOG_LEVEL_WARNING, "Can't read /sys/class/tty/tty0/active");
+                continue;
+            }
+            buffer[size] = 0;
+
+            unsigned int tty;
+            if (sscanf(buffer, "tty%u", &tty) != 1) {
+                bbx_log(BBX_LOG_LEVEL_WARNING, "Unexpected value of /sys/class/tty/tty0/active");
+                continue;
+            }
+
+            if (!bb_terminal_is_busy(tty)) {
+                bbx_log(BBX_LOG_LEVEL_VERBOSE, "Terminal %u isn't used, skip automatic update.", tty);
+                continue;
+            }
+        }
+
+        bb_terminal_shrink_current();
+        lv_obj_invalidate(keyboard);
     }
 
     return 0;

buffyboard/meson.build

@@ -40,4 +40,10 @@ if depsystemd.found()
         install_dir: system_unit_dir,
         install_tag: 'buffyboard'
     )
+
+    install_data('getty-buffyboard.conf',
+        rename: 'buffyboard.conf',
+        install_dir: system_unit_dir / 'getty@.service.d',
+        install_tag: 'buffyboard'
+    )
 endif

buffyboard/terminal.c

@@ -3,16 +3,14 @@
  * SPDX-License-Identifier: GPL-3.0-or-later
  */
 
-
 #include "terminal.h"
 
-#include <errno.h>
 #include <fcntl.h>
-#include <math.h>
+#include <limits.h>
 #include <stdio.h>
-#include <string.h>
 #include <unistd.h>
 
+#include <linux/kd.h>
 #include <linux/vt.h>
 
 #include <sys/ioctl.h>
@@ -22,260 +20,121 @@
  * Static variables
  */
 
-static int current_fd = -1;
+static int32_t _tty_size;
-static int current_vt = -1;
+static int32_t _h_display_size;
-static bool resized_vts[MAX_NR_CONSOLES];
+static int32_t _v_display_size;
-static float height_factor = 1;
-
-
-/**
- * Static prototypes
- */
-
-/**
- * Close the current file descriptor and reopen /dev/tty0.
- * 
- * @return true if opening was successful, false otherwise
- */
-static bool reopen_current_terminal(void);
-
-/**
- * Close the current file descriptor.
- */
-static void close_current_terminal(void);
-
-/**
- * Get the currently active virtual terminal.
- * 
- * @return number of the active VT (e.g. 7 for /dev/tty7)
- */
-static int get_active_terminal(void);
-
-/**
- * Retrieve a terminal's size.
- * 
- * @param fd TTY file descriptor
- * @param size pointer to winsize struct for writing the size into
- * @return true if the operation was successful, false otherwise. On failure, errno will be set
- * to the value set by the failed system call.
- */
-static bool get_terminal_size(int fd, struct winsize *size);
-
-/**
- * Update a terminal's size.
- * 
- * @param fd TTY file descriptor
- * @param size pointer to winsize struct for reading the new size from
- * @return true if the operation was successful, false otherwise. On failure, errno will be set
- * to the value set by the failed system call.
- */
-static bool set_terminal_size(int fd, struct winsize *size);
-
-/**
- * Shrink the height of a terminal by the current factor.
- * 
- * @param fd TTY file descriptor
- * @return true if the operation was successful, false otherwise
- */
-static bool shrink_terminal(int fd);
-
-/**
- * Reset the height of a terminal to the maximum.
- * 
- * @param fd TTY file descriptor
- * @param size pointer to winsize struct for writing the final size into
- * @return true if the operation was successful, false otherwise
- */
-static bool reset_terminal(int fd, struct winsize *size);
-
-
-/**
- * Static functions
- */
-
-static bool reopen_current_terminal(void) {
-    close_current_terminal();
-
-    current_fd = open("/dev/tty0", O_RDWR | O_NOCTTY);
-	if (current_fd < 0) {
-		perror("Could not open /dev/tty0");
-		return false;
-	}
-
-    return true;
-}
-
-static void close_current_terminal(void) {
-    if (current_fd < 0) {
-        return;
-    }
-
-    close(current_fd);
-    current_fd = -1;
-}
-
-static int get_active_terminal(void) {
-    struct vt_stat stat;
-    if (ioctl(current_fd, VT_GETSTATE, &stat) != 0) {
-        perror("Could not retrieve current termimal state");
-        return -1;
-    }
-    return stat.v_active;
-}
-
-static bool get_terminal_size(int fd, struct winsize *size) {
-	if (ioctl(fd, TIOCGWINSZ, size) != 0) {
-        int errsv = errno;
-        perror("Could not retrieve current terminal size");
-        errno = errsv;
-        return false;
-	}
-    return true;
-}
-
-static bool set_terminal_size(int fd, struct winsize *size) {
-    if (ioctl(fd, TIOCSWINSZ, size) != 0) {
-        int errsv = errno;
-        perror("Could not update current terminal size");
-        errno = errsv;
-        return false;
-    }
-    return true;
-}
-
-static bool shrink_terminal(int fd) {
-    struct winsize size = { 0, 0, 0, 0 };
-    
-    if (!reset_terminal(fd, &size)) {
-        perror("Could not shrink terminal size");
-        return false;
-    }
-
-    size.ws_row = floor((float)size.ws_row * height_factor);
-    if (!set_terminal_size(fd, &size)) {
-        perror("Could not shrink terminal size");
-        return false;
-    }
-
-    return true;
-}
-
-static bool reset_terminal(int fd, struct winsize *size) {
-    if (!get_terminal_size(fd, size)) {
-        perror("Could not reset terminal size");
-        return false;
-    }
-
-    /* Test-resize by two rows. If the terminal is already maximised, this will fail and we can exit early. */
-    size->ws_row += 2;
-    if (!set_terminal_size(fd, size)) {
-        bool is_max = (errno == EINVAL);
-        size->ws_row -= 2;
-        return is_max;
-    }
-
-    size->ws_row = floor((float)size->ws_row / height_factor);
-    if (!set_terminal_size(fd, size)) {
-        if (errno != EINVAL) {
-            perror("Could not reset terminal size");
-            return false;
-        }
-
-        /* Size too large. Reduce by one row until it fits. */
-        do {
-            size->ws_row -= 1;
-        } while (size->ws_row > 0 && !set_terminal_size(fd, size) && errno == EINVAL);
-
-        if (errno != EINVAL || size->ws_row == 0) {
-            perror("Could not reset terminal size");
-            return false;
-        }
-    } else {
-        /* Size fits but may not max out available space. Increase by one row until it doesn't fit anymore. */
-        do {
-            size->ws_row += 1;
-        } while (set_terminal_size(fd, size));
-
-        if (errno != EINVAL) {
-            perror("Could not reset terminal size");
-            return false;
-        }
-
-        size->ws_row -= 1;
-    }
-
-    return true;
-}
 
 
 /**
  * Public functions
  */
 
-bool bb_terminal_init(float factor) {
+void bb_terminal_init(int32_t tty_size, int32_t h_display_size, int32_t v_display_size) {
-    if (!reopen_current_terminal()) {
+    _tty_size = tty_size;
-        perror("Could not prepare for terminal resizing");
+    _h_display_size = h_display_size;
+    _v_display_size = v_display_size;
+}
+
+void bb_terminal_shrink_current() {
+    int fd = open("/dev/tty0", O_RDONLY|O_NOCTTY);
+    if (fd < 0)
+        return;
+
+    /* KDFONTOP returns EINVAL if we are not in the text mode,
+       so we can skip this check */
+/*
+    int mode;
+    if (ioctl(fd, KDGETMODE, &mode) != 0)
+        goto end;
+
+    if (mode != KD_TEXT)
+        goto end;
+*/
+    struct console_font_op cfo = {
+        .op = KD_FONT_OP_GET,
+        .width = UINT_MAX,
+        .height = UINT_MAX,
+        .charcount = UINT_MAX,
+        .data = NULL
+    };
+    if (ioctl(fd, KDFONTOP, &cfo) != 0)
+        goto end;
+
+    struct winsize size;
+    size.ws_row = _tty_size / cfo.height;
+    size.ws_col = _h_display_size / cfo.width;
+    ioctl(fd, TIOCSWINSZ, &size);
+end:
+    close(fd);
+}
+
+void bb_terminal_reset_all() {
+    int fd = open("/dev/tty0", O_RDONLY|O_NOCTTY);
+    if (fd < 0)
+        return;
+
+    struct vt_stat state;
+    if (ioctl(fd, VT_GETSTATE, &state) != 0) {
+        close(fd);
+        return;
+    }
+
+    close(fd);
+
+    char buffer[sizeof("/dev/tty") + 2];
+    unsigned short mask = state.v_state >> 1;
+    unsigned int tty = 1;
+
+    for (; mask; mask >>= 1, tty++) {
+        if (mask & 0x01) {
+            sprintf(buffer, "/dev/tty%u", tty);
+            int tty_fd = open(buffer, O_RDONLY|O_NOCTTY);
+            if (tty_fd < 0)
+                continue;
+
+            /* KDFONTOP returns EINVAL if we are not in the text mode,
+               so we can skip this check */
+/*
+            int mode;
+            if (ioctl(tty_fd, KDGETMODE, &mode) != 0)
+                goto end;
+
+            if (mode != KD_TEXT)
+                goto end;
+*/
+            struct console_font_op cfo = {
+                .op = KD_FONT_OP_GET,
+                .width = UINT_MAX,
+                .height = UINT_MAX,
+                .charcount = UINT_MAX,
+                .data = NULL
+            };
+            if (ioctl(tty_fd, KDFONTOP, &cfo) != 0)
+                goto end;
+
+            struct winsize size;
+            size.ws_row = _v_display_size / cfo.height;
+            size.ws_col = _h_display_size / cfo.width;
+            ioctl(tty_fd, TIOCSWINSZ, &size);
+end:
+            close(tty_fd);
+        }
+    }
+}
+
+bool bb_terminal_is_busy(unsigned int tty) {
+    /* We can use any other terminal than `tty` here. */
+    int fd = open(tty == 1? "/dev/tty2" : "/dev/tty1", O_RDONLY|O_NOCTTY);
+    if (fd < 0)
         return false;
-    }
 
-    current_vt = get_active_terminal();
+    struct vt_stat state;
-    if (current_vt < 0) {
+    int r = ioctl(fd, VT_GETSTATE, &state);
-        perror("Could not prepare for terminal resizing");
+
+    close(fd);
+
+    if (r != 0)
         return false;
-    }
 
-    height_factor = factor;
+    return (state.v_state >> tty) & 0x01;
-    return true;
-}
-
-void bb_terminal_shrink_current(void) {
-    int active_vt = get_active_terminal();
-    if (active_vt < 0) {
-        perror("Could not resize current terminal");
-        return;
-    }
-
-    if (active_vt < 0 || active_vt > MAX_NR_CONSOLES - 1) {
-        perror("Could not resize current terminal, index is out of bounds");
-        return;
-    }
-
-    if (resized_vts[active_vt - 1]) {
-        return; /* Already resized */
-    }
-
-    if (active_vt != current_vt) {
-        if (!reopen_current_terminal()) {
-            perror("Could not resize current terminal");
-            return;
-        }
-        current_vt = active_vt;
-    }
-
-    if (!shrink_terminal(current_fd)) {
-        perror("Could not resize current terminal");
-        return;
-    }
-
-    resized_vts[current_vt - 1] = true;
-}
-
-void bb_terminal_reset_all(void) {
-    char device[16];
-    struct winsize size = { 0, 0, 0, 0 };
-
-    for (int i = 0; i < MAX_NR_CONSOLES; ++i) {
-        if (!resized_vts[i]) {
-            continue;
-        }
-
-        snprintf(device, 16, "/dev/tty%d", i + 1);
-        int fd = open(device, O_RDWR | O_NOCTTY);
-        if (fd < 0) {
-            perror("Could not reset TTY, unable to open TTY");
-            continue;
-        }
-
-        reset_terminal(fd, &size);
-    }
 }

buffyboard/terminal.h

@@ -8,24 +8,30 @@
 #define BB_TERMINAL_H
 
 #include <stdbool.h>
+#include <stdint.h>
 
 /**
- * Prepare for resizing terminals by opening the current one.
+ * Prepare for resizing terminals.
  * 
- * @param factor factor (between 0 and 1) by which to adapt terminal sizes
+ * @param tty_size vertical size of the tty area in pixels
- * @return true if the operation was successful, false otherwise. No other bb_terminal_* functions
+ * @param h_display_size horizontal resolution of the display in pixels
- * must be called if false is returned.
+ * @param v_display_size vertical resolution of the display in pixels
  */
-bool bb_terminal_init(float factor);
+void bb_terminal_init(int32_t tty_size, int32_t h_display_size, int32_t v_display_size);
 
 /**
- * Shrink the height of the active terminal by the current factor.
+ * Shrink the height of the active terminal.
  */
-void bb_terminal_shrink_current(void);
+void bb_terminal_shrink_current();
 
 /**
- * Re-maximise the height of all previously resized terminals.
+ * Re-maximise the size of all active terminals.
  */
-void bb_terminal_reset_all(void);
+void bb_terminal_reset_all();
+
+/**
+ * Check whether the terminal is opened by some process
+ */
+bool bb_terminal_is_busy(unsigned int tty);
 
 #endif /* BB_TERMINAL_H */

man/buffyboard.1.scd

@@ -52,6 +52,15 @@ result.
 *-V, --version*
 	Print the unl0kr version and exit.
 
+# NOTES
+
+Some terminal commands, like _clear_ or _setfont_, can erase the keyboard or brake the layout of the terminal. In this case you should send a signal to Buffyboard or switch to another terminal to update the screen:
+
+```
+setfont solar24x32;/usr/bin/kill -s SIGUSR1 buffyboard
+setfont solar24x32;chvt $((`fgconsole`+1));chvt $((`fgconsole`-1))
+```
+
 # EXAMPLES
 
 *Execute Buffyboard using the default config*

man/buffyboard.conf.5.scd

@@ -45,6 +45,17 @@ for and, if found, merged in the following order:
 	after every draw operation. This has a negative performance impact.
 	Default: false.
 
+*ignore_unused_terminals* = <true|false>
+	If true, buffyboard won't automatically update the layout of a new terminal and
+	draw the keyboard, if the terminal is not opened by any process. In this case
+	SIGUSR1 should be sent to buffyboard to update the layout. This quirk was introduced to resolve a race between buffyboard and systemd-logind according to the following scenario:
+	- A user switches to a new virtual terminal
+	- Buffyboard opens the terminal and changes the number of rows
+	- systemd-logind sees that the terminal is opened by some other process and don't start getty@.service
+
+	The race is resolved by enabling this option and installing a drop-in file
+	for getty@.service that sends SIGUSR1 to buffyboard. Default: true.
+
 # SEE ALSO
 	*buffyboard*(1)