kernel settings file

doc/internal/settings.txt

@@ -0,0 +1,31 @@
+header format:
+  dword: offset of main area start
+  dword: number of main area entries
+  dword: offset of name area start
+  dword: offset of data area start
+
+main area entry format:
+  dword: offset into name area of setting name
+  byte: setting name length
+  byte: setting type
+    0x00: string
+    0x01: color
+    others: reserved
+  word: reserved
+  qword:
+    if sz string:
+      dword: offset into data area of start
+      dword: length of string
+    if color:
+      byte: red value
+      byte: green value
+      byte: blue value
+      byte: reserved
+      dword: reserved
+
+currently used settings:
+  "kbd-layout", sz string:
+    the name of the scancode table for the keyboard driver to use.
+    if it is <layout>, the file at sys/scantabs/<layout>.sct is loaded.
+  "wm-border-color", color:
+    the color to use for window borders

makefile

@@ -55,7 +55,7 @@ out/kernel.bin: obj/kernel/drive.ko  obj/kernel/fat.ko    obj/kernel/ide.ko  \
                 obj/kernel/serial.ko obj/kernel/task.ko   obj/kernel/util.ko \
                 obj/kernel/window.ko obj/kernel/isrs.kao  obj/kernel/kbd.ko  \
                 obj/kernel/pmap.ko   obj/kernel/paging.ko obj/kernel/dump.ko \
-                obj/kernel/cmos.ko
+                obj/kernel/cmos.ko   obj/kernel/settings.ko
 	mkdir -p out
 	ld -T src/kernel/elf-link.ld $^ -o obj/kernel.elf
 	objcopy -O binary obj/kernel.elf out/kernel.bin

src/kernel/kbd.c

@@ -1,14 +1,16 @@
 #include <stdint.h>
 
+#include "settings.h"
 #include "window.h"
 #include "drive.h"
 #include "panic.h"
 #include "pmap.h"
 #include "util.h"
 #include "kbd.h"
+#include "log.h"
 
-#define SCANTAB_DIR "sys/scantabs"
+#define SCANTAB_DIR "sys/scantabs/"
-#define LAYOUT_HARDCODE_TMP "qwerty"
+#define SCANTAB_DIR_LEN 13
 
 enum {
   PS2_CMD  = 0x64,
@@ -45,14 +47,29 @@ enum {
   ST_SKIP
 };
 
+#define LAYOUT_NAME_MAX_LEN 31
+static char scantab_path[SCANTAB_DIR_LEN + LAYOUT_NAME_MAX_LEN + 5] = SCANTAB_DIR;
+
 void init_kbd() {
   outb(PS2_CMD, PS2C_READ_CONFIG);
   uint8_t config = inb(PS2_DATA);
   outb(PS2_CMD, PS2C_WRITE_CONFIG);
   outb(PS2_DATA, config | PS2G_XT_COMPAT);
 
-  //TODO: get layout from some config file
+  uint32_t layout_len;
-  file_id_t stf = drives->get_file(drives, SCANTAB_DIR "/" LAYOUT_HARDCODE_TMP ".sct");
+  if (!try_get_sz_setting("kbd-layout", scantab_path + SCANTAB_DIR_LEN, LAYOUT_NAME_MAX_LEN, &layout_len))
+    PANIC("keyboard layout not found in settings file.");
+  if (layout_len == LAYOUT_NAME_MAX_LEN)
+    logf(LOG_WARN, "keyboard layout name potentially cropped.");
+  scantab_path[SCANTAB_DIR_LEN + layout_len] = '.';
+  scantab_path[SCANTAB_DIR_LEN + layout_len + 1] = 's';
+  scantab_path[SCANTAB_DIR_LEN + layout_len + 2] = 'c';
+  scantab_path[SCANTAB_DIR_LEN + layout_len + 3] = 't';
+  scantab_path[SCANTAB_DIR_LEN + layout_len + 4] = '\0';
+  logf(LOG_INFO, "Using scantab file at \"%s\".", scantab_path);
+  file_id_t stf = drives->get_file(drives, scantab_path);
+  if (!stf)
+    PANIC("could not load scantab file.");
 
   fmcpy(&n_scantabs, drives, stf, 0, 4);
   scantabs = allocate_kernel_pages((sizeof(struct scantab_info) * n_scantabs - 1) / 4096 + 1);

src/kernel/main.c

@@ -1,4 +1,4 @@
-#include <stdint.h>
+#include "settings.h"
 #include "paging.h"
 #include "serial.h"
 #include "window.h"
@@ -17,6 +17,8 @@
 #include "pci.h"
 #include "vbe.h"
 
+#include <stdint.h>
+
 void _start_user_mode() __attribute__ ((noreturn));
 
 __attribute__ ((noreturn))
@@ -25,7 +27,6 @@ void main() {
   init_paging();
   init_tasks();
   init_serial();
-
   pci_init();
 
   init_fat();
@@ -37,10 +38,10 @@ void main() {
   //other drive drivers
 
   init_log();
+  init_settings();
 
   init_kbd();
   init_idt();
-
   init_win();
 
   logf(LOG_INFO, "Kernel initialization done.");

src/kernel/settings.c

@@ -0,0 +1,91 @@
+#include "window.h"
+#include "drive.h"
+#include "panic.h"
+#include "util.h"
+
+#include <stdint.h>
+
+#define SETTINGS_FILE "sys/settings.pls"
+
+static struct {
+  uint32_t main_start;
+  uint32_t main_entries;
+  uint32_t names_start;
+  uint32_t data_start;
+} settings_header;
+
+enum {
+  ST_SZ_STRING = 0x00,
+  ST_COLOR     = 0x01
+};
+
+struct main_entry {
+  uint32_t name_offset;
+  uint8_t name_len;
+  uint8_t type;
+  uint16_t pad;
+  union {
+    struct {
+      uint32_t data_offset;
+      uint32_t length;
+    } as_string;
+    struct pixel as_pixel;
+  };
+} __attribute__ ((__packed__));
+
+static file_id_t fid;
+static uint32_t main_end;
+
+void init_settings() {
+  fid = drives->get_file(drives, SETTINGS_FILE);
+  if (!fid)
+    PANIC("could not open settings file at \"" SETTINGS_FILE "\".");
+
+  fmcpy(&settings_header, drives, fid, 0, 16);
+
+  main_end = settings_header.main_start + settings_header.main_entries * sizeof(struct main_entry);
+}
+
+bool try_find_setting(const char *name, struct main_entry *entry_out) {
+  uint16_t name_len = 0;
+  while (name[name_len])
+    if (++name_len == 256)
+      return false;
+
+  for (uint32_t i = settings_header.main_start; i < main_end; i += sizeof(struct main_entry)) {
+    fmcpy(entry_out, drives, fid, i, sizeof(struct main_entry));
+    if (entry_out->name_len != name_len)
+      continue;
+    char found_name[255];
+    fmcpy(found_name, drives, fid, settings_header.names_start + entry_out->name_offset, name_len);
+    for (uint8_t j = 0; j < name_len; ++j)
+      if (found_name[j] != name[j])
+        goto lc;
+    return true;
+  lc:
+    ;
+  }
+
+  return false;
+}
+
+bool try_get_sz_setting(const char *name, char *out, uint32_t max_len, uint32_t *len_out) {
+  struct main_entry entry;
+  if (!try_find_setting(name, &entry) || (entry.type != ST_SZ_STRING))
+    return false;
+
+  const uint32_t len = entry.as_string.length > max_len ? max_len : entry.as_string.length;
+  fmcpy(out, drives, fid, settings_header.data_start + entry.as_string.data_offset, len);
+  out[len] = '\0';
+  *len_out = len;
+  return true;
+}
+
+bool try_get_color_setting(const char *name, struct pixel *out) {
+  struct main_entry entry;
+  if (!try_find_setting(name, &entry) || (entry.type != ST_COLOR))
+    return false;
+
+  *out = entry.as_pixel;
+  return true;
+}

src/kernel/settings.h

@@ -0,0 +1,16 @@
+#ifndef SETTINGS_H
+#define SETTINGS_H
+
+#include "window.h"
+
+#include <stdbool.h>
+#include <stdint.h>
+
+void init_settings();
+
+//lengths do not include null terminator. if setting value is too long, it is cropped.
+bool try_get_sz_setting(const char *name, char *out, uint32_t max_len, uint32_t *len_out);
+
+bool try_get_color_setting(const char *name, struct pixel *out);
+
+#endif

src/kernel/window.c

@@ -1,3 +1,4 @@
+#include "settings.h"
 #include "paging.h"
 #include "window.h"
 #include "drive.h"
@@ -16,7 +17,7 @@
 #define GSC(x, y) (x / 4 + y / 4 >= 256 ? 255 : x / 4 + y / 4)
 #define BACKGROUND(x, y) ((struct pixel){.r = GSC(x / 2, y / 3), .g = GSC(x, y), .b = GSC(x, y / 2)})
 
-#define BORDER_COLOR ((struct pixel){.r = 0x11, .g = 0x11, .b = 0x11})
+static struct pixel border_color;
 
 #define MOVE_BY 5
 
@@ -52,6 +53,8 @@ static void load_mode_params() {
   const uint32_t fb_len = VBE_MODE_INFO->width * VBE_MODE_INFO->height;
   buffer_pages = (fb_len * sizeof(struct pixel) - 1) / 4096 + 1;
   buffer = allocate_kernel_pages(buffer_pages);
+  if (!buffer)
+    PANIC("could not allocate intermediate framebuffer");
 
   #define MASK(offset, length) ((~((1 << offset) - 1)) - (offset + length == 32 ? 0 : (~((1 << (offset + length)) - 1))))
   pix_clear_mask = ~(
@@ -116,14 +119,14 @@ static void paint_and_above(const struct window *w) {
       for (uint16_t x = xs; x < xm; ++x)
         buffer[((y + i->ypos) & 0xffff) * VBE_MODE_INFO->width + ((x + i->xpos) & 0xffff)] = i->pixel_buffer_pma[y * i->width + x];
 
-    draw_hz_line(i->ypos             - 2, i->xpos - 2, i->xpos + i->width + 2, BORDER_COLOR);
+    draw_hz_line(i->ypos             - 2, i->xpos - 2, i->xpos + i->width + 2, border_color);
-    draw_hz_line(i->ypos             - 1, i->xpos - 2, i->xpos + i->width + 2, BORDER_COLOR);
+    draw_hz_line(i->ypos             - 1, i->xpos - 2, i->xpos + i->width + 2, border_color);
-    draw_hz_line(i->ypos + i->height,     i->xpos - 2, i->xpos + i->width + 2, BORDER_COLOR);
+    draw_hz_line(i->ypos + i->height,     i->xpos - 2, i->xpos + i->width + 2, border_color);
-    draw_hz_line(i->ypos + i->height + 1, i->xpos - 2, i->xpos + i->width + 2, BORDER_COLOR);
+    draw_hz_line(i->ypos + i->height + 1, i->xpos - 2, i->xpos + i->width + 2, border_color);
-    draw_vt_line(i->xpos             - 2, i->ypos,     i->ypos + i->height,    BORDER_COLOR);
+    draw_vt_line(i->xpos             - 2, i->ypos,     i->ypos + i->height,    border_color);
-    draw_vt_line(i->xpos             - 1, i->ypos,     i->ypos + i->height,    BORDER_COLOR);
+    draw_vt_line(i->xpos             - 1, i->ypos,     i->ypos + i->height,    border_color);
-    draw_vt_line(i->xpos + i->width,      i->ypos,     i->ypos + i->height,    BORDER_COLOR);
+    draw_vt_line(i->xpos + i->width,      i->ypos,     i->ypos + i->height,    border_color);
-    draw_vt_line(i->xpos + i->width  + 1, i->ypos,     i->ypos + i->height,    BORDER_COLOR);
+    draw_vt_line(i->xpos + i->width  + 1, i->ypos,     i->ypos + i->height,    border_color);
   }
 
   blit();
@@ -296,6 +299,9 @@ static char *run_command;
 static char *run_command_pass = "";
 
 void init_win() {
+  if (!try_get_color_setting("wm-border-color", &border_color))
+    PANIC("could not load window border color setting.");
+
   buffer = 0;
   load_mode_params();