file manager

28 files changed, 539 insertions, 187 deletions

diff --git a/src/kernel/drive.c b/src/kernel/drive.c
index 731088c..2ae050f 100644
--- a/src/kernel/drive.c
+++ b/src/kernel/drive.c
@@ -36,6 +36,11 @@ static uint32_t unknown_enumerate_dir(const struct drive *d, const char *path, s
   return 0;
 }
 
+__attribute__ ((const))
+static uint32_t unknown_n_dir_entries(const struct drive *d, const char *path) {
+  return 0;
+}
+
 static inline void determine_fs(struct drive *d) {
   if (try_fat_init_drive(d))
     return;
@@ -46,6 +51,7 @@ static inline void determine_fs(struct drive *d) {
   d->load_sector = &unknown_load_sector;
   d->get_file_length = &unknown_get_file_length;
   d->enumerate_dir = &unknown_enumerate_dir;
+  d->n_dir_entries = &unknown_n_dir_entries;
   d->get_free_sectors = &unknown_get_free_sectors;
 }
 
diff --git a/src/kernel/drive.h b/src/kernel/drive.h
index b02b4ad..03fe4b6 100644
--- a/src/kernel/drive.h
+++ b/src/kernel/drive.h
@@ -13,10 +13,11 @@ typedef uint8_t drive_id_t;
 #define DCI_NAME_LEN 100
 
 struct directory_content_info {
-  bool is_dir;
   char name[DCI_NAME_LEN];
   uint32_t size;
-};
+  bool is_dir;
+  uint8_t pad[23];
+} __attribute__ ((packed));
 
 struct drive {
   char *drive_type;
@@ -34,6 +35,7 @@ struct drive {
   void      (*load_sector)     (const struct drive *d, file_id_t fid, uint32_t sector, void *at);
   uint32_t  (*get_file_length) (const struct drive *d, file_id_t fid);
   uint32_t  (*enumerate_dir)   (const struct drive *d, const char *path, struct directory_content_info *info, uint32_t max);
+  uint32_t  (*n_dir_entries)   (const struct drive *d, const char *path);
   uint32_t  (*get_free_sectors)(const struct drive *d);
   fs_id_t fs_id;
 };
diff --git a/src/kernel/fat.c b/src/kernel/fat.c
index c4461de..362539c 100644
--- a/src/kernel/fat.c
+++ b/src/kernel/fat.c
@@ -365,6 +365,72 @@ static uint32_t fat_enumerate_dir(const struct drive *d, const char *path, struc
   }
 }
 
+static uint32_t n_root_entries(const struct drive *d) {
+  uint32_t sect = infos[d->drive_id].root_start - 1;
+  struct directory_entry *entry = (struct directory_entry *)(fat_driver_buffer + 512);
+
+  uint32_t count = 0;
+
+  while (true) {
+    if (entry == (struct directory_entry *)(fat_driver_buffer + 512)) {
+      entry = (struct directory_entry *)fat_driver_buffer;
+      ++sect;
+      d->read_sectors(d, sect, 1, entry);
+    }
+
+    if (!*(uint8_t *)entry) {
+      d->done(d);
+      return count;
+    }
+
+    if (entry-> attrib & FA_LABEL) {
+      ++entry;
+      continue;
+    }
+
+    ++entry;
+    ++count;
+  }
+}
+
+static uint32_t fat_n_dir_entries(const struct drive *d, const char *path) {
+  d->ready(d);
+
+  if (!*path)
+    return n_root_entries(d);
+
+  if (!try_load_from_path(d, path)) {
+    d->done(d);
+    return 0;
+  }
+
+  uint16_t cluster = cur_dir->first_cluster;
+  load_cluster(cluster, fat_driver_buffer);
+  struct directory_entry *entry = (struct directory_entry *)fat_driver_buffer;
+
+  uint32_t count = 0;
+
+  while (true) {
+    if (entry == (struct directory_entry *)(fat_driver_buffer + 512)) {
+      entry = (struct directory_entry *)fat_driver_buffer;
+      load_cluster(cluster = next_cluster(cluster), fat_driver_buffer);
+    }
+
+    if (!*(uint8_t *)entry) {
+      d->done(d);
+      return count;
+    }
+
+    if (check_fat_names(entry->name, this_dir) || check_fat_names(entry->name, parent_dir)) {
+      ++entry;
+      continue;
+    }
+
+    ++entry;
+    ++count;
+  }
+}
+
 void init_fat() {
   next_fi = allocate_kernel_pages(1);
   next_id = 0;
@@ -388,6 +454,7 @@ bool try_fat_init_drive(struct drive *d) {
   d->load_sector = &fat_load_sector;
   d->get_file_length = &fat_get_file_length;
   d->enumerate_dir = &fat_enumerate_dir;
+  d->n_dir_entries = &fat_n_dir_entries;
   d->get_free_sectors = &fat_get_free_sectors;
 
   d->fs_id = next_id;
diff --git a/src/kernel/idt.c b/src/kernel/idt.c
index 90d8dc3..1b8e548 100644
--- a/src/kernel/idt.c
+++ b/src/kernel/idt.c
@@ -8,6 +8,7 @@
 #include "paging.h"
 #include "pmap.h"
 #include "kbd.h"
+#include "vga.h"
 
 enum {
   IDT_PRESENT = 0x80,
@@ -100,6 +101,10 @@ static uint32_t sc_enumerate_dir(uint32_t drive_number, const char *path, struct
   return drives[drive_number].enumerate_dir(drives + drive_number, path, buffer, max_entries);
 }
 
+static uint32_t sc_count_of_dir(uint32_t drive_number, const char *path) {
+  return drives[drive_number].n_dir_entries(drives + drive_number, path);
+}
+
 void const *syscall_table[] = {
   &sc_open_file,
   &sc_close_file,
@@ -111,7 +116,11 @@ void const *syscall_table[] = {
   &sc_allocate_ram,
   &sc_memory_info,
   &sc_wait_for_task,
-  &sc_enumerate_dir
+  &sc_enumerate_dir,
+  &vga_print_at,
+  &sc_count_of_dir,
+  &vga_blank,
+  &vga_set_color
 };
 
 //these aren't really void ()'s, but gcc complains if we take an address of a void, so we give it a type
diff --git a/src/kernel/isrs.asm b/src/kernel/isrs.asm
index 6ad469d..e7573ae 100644
--- a/src/kernel/isrs.asm
+++ b/src/kernel/isrs.asm
@@ -23,7 +23,7 @@ extern on_kbd_isr
 extern make_sure_tasks
 extern exception_halt
 
-n_syscalls equ 0xb
+n_syscalls equ 0xf
 
 ;section .bss
 ;_debug_is_start_task resb 1
diff --git a/src/kernel/kbd.c b/src/kernel/kbd.c
index f3eb323..c251db7 100644
--- a/src/kernel/kbd.c
+++ b/src/kernel/kbd.c
@@ -226,19 +226,34 @@ static const uint8_t codes_e0[] = {
   0,             0,    0,    0,              0,              0,              0, 0
 };
 
+#include "log.h"
+
+uint8_t get_code_byte() {
+  for (uint32_t spin = 0; spin < 10000000; ++spin)
+    ;
+  return inb(PS2_DATA);
+}
+
 void on_kbd_isr() {
   while (inb(PS2_CMD) & PS2S_CODE_READY) {
-    uint8_t code = inb(PS2_DATA);
+  //char nbuf[11];
+    uint8_t code = get_code_byte();
+  //logsz("code: 0x");
+  //u8_hex(code, nbuf);
+  //logsz(nbuf);
     if (code == 0xe1) {
-      code = inb(PS2_DATA);
+      code = get_code_byte();
+    //logsz(" 0x");
+    //u8_hex(code, nbuf);
+    //logsz(nbuf);
       if (code == 0x1d) {
-        if (inb(PS2_DATA) != 0x45)
+        if (get_code_byte() != 0x45)
           code = 0;
         else
           code = CODE_PAUSE;
       }
       else if (code == 0x9d) {
-        if (inb(PS2_DATA) != 0xc5)
+        if (get_code_byte() != 0xc5)
           code = 0;
         else
           code = 0xff;
@@ -247,17 +262,20 @@ void on_kbd_isr() {
         code = 0;
     }
     else if (code == 0xe0) {
-      code = inb(PS2_DATA);
+      code = get_code_byte();
+    //logsz(" 0x");
+    //u8_hex(code, nbuf);
+    //logsz(nbuf);
       if (code == 0x2a) {
-        if ((inb(PS2_DATA) != 0xe0) ||
-            (inb(PS2_DATA) != 0x37))
+        if ((get_code_byte() != 0xe0) ||
+            (get_code_byte() != 0x37))
           code = 0;
         else
           code = CODE_PRSCR;
       }
       else if (code == 0xb7) {
-        if ((inb(PS2_DATA) != 0xe0) ||
-            (inb(PS2_DATA) != 0xaa))
+        if ((get_code_byte() != 0xe0) ||
+            (get_code_byte() != 0xaa))
           code = 0;
         else
           code = 0xff;
@@ -268,6 +286,8 @@ void on_kbd_isr() {
     else
       code = codes[code];
 
+  //logch('\n');
+
     if (!code)
       PANIC("Unknown scancode.");
 
diff --git a/src/kernel/main.c b/src/kernel/main.c
index 06b83d1..b34f816 100644
--- a/src/kernel/main.c
+++ b/src/kernel/main.c
@@ -15,9 +15,6 @@
 #include "vga.h"
 #include "kbd.h"
 
-void reset_tree();
-void tree(struct drive *d);
-
 void _start_user_mode() __attribute__ ((noreturn));
 
 __attribute__ ((noreturn))
@@ -35,6 +32,7 @@ void main() {
 
   pci_init();
 
+/*
   u16_dec(n_pci_devices, nbuf);
   logsz(nbuf);
   logsz(" PCI device(s) found:\n");
@@ -63,6 +61,7 @@ void main() {
   }
 
   logch('\n');
+*/
 
   init_fat();
   //other fs drivers
@@ -72,6 +71,7 @@ void main() {
   init_ide();
   //other drive drivers
 
+/*
   u8_dec(n_drives, nbuf);
   logsz(nbuf);
   logsz(" drive(s) found:\n");
@@ -108,20 +108,7 @@ void main() {
   }
 
   logch('\n');
-
-  for (uint8_t n = 0;  n < n_drives; ++n) {
-    if (drives[n].get_free_sectors(drives + n) == -1)
-      continue;
-
-    u32_dec(n, nbuf);
-    logsz("sd");
-    logsz(nbuf);
-    logsz(" tree:\n");
-
-    reset_tree();
-    tree(drives + n);
-    logch('\n');
-  }
+*/
 
   if (BOOT_INFO->support_flags & BIS_PAE)
     logsz("Processor supports PAE (but Portland OS does not yet).\n");
diff --git a/src/kernel/main2.c b/src/kernel/main2.c
deleted file mode 100644
index 27ef8de..0000000
--- a/src/kernel/main2.c
+++ /dev/null
@@ -1,69 +0,0 @@
-#include <stdint.h>
-#include "drive.h"
-#include "util.h"
-#include "log.h"
-
-static char nbuf2[11];
-
-static char path_builder[200];
-static uint8_t path_builder_len;
-
-static char indent_builder[20];
-static uint8_t indent_builder_len;
-
-void reset_tree() {
-  path_builder[0] = '\0';
-  path_builder_len = 0;
-
-  indent_builder[0] = ' ';
-  indent_builder[1] = ' ';
-  indent_builder[2] = '\0';
-  indent_builder_len = 2;
-}
-
-void tree(struct drive *d) {
-  struct directory_content_info infos[100];
-  uint8_t n_infos = d->enumerate_dir(d, path_builder, infos, 100);
-
-  if (!n_infos) {
-    logsz(indent_builder);
-    logsz("(empty)\n");
-    return;
-  }
-
-  for (uint8_t i = 0; i < n_infos; ++i) {
-    logsz(indent_builder);
-    logsz(infos[i].name);
-
-    if (infos[i].is_dir) {
-      logsz(":\n");
-
-      indent_builder[indent_builder_len] = ' ';
-      indent_builder[indent_builder_len + 1] = ' ';
-      indent_builder[indent_builder_len + 2] = '\0';
-      indent_builder_len += 2;
-
-      uint8_t name_length = 0;
-      while (infos[i].name[name_length])
-        ++name_length;
-
-      memcpy(path_builder + path_builder_len, infos[i].name, name_length + 1);
-      path_builder_len += name_length;
-
-      tree(d);
-
-      path_builder_len -= name_length;
-      path_builder[path_builder_len] = '\0';
-
-      indent_builder_len -= 2;
-      indent_builder[indent_builder_len] = '\0';
-    }
-
-    else {
-      u32_dec(infos[i].size, nbuf2);
-      logsz(" (");
-      logsz(nbuf2);
-      logsz(" bytes)\n");
-    }
-  }
-}
\ No newline at end of file
diff --git a/src/kernel/vga.c b/src/kernel/vga.c
index daa92fe..42da312 100644
--- a/src/kernel/vga.c
+++ b/src/kernel/vga.c
@@ -2,8 +2,9 @@
 #include <stdint.h>
 
 #define VGA_COLUMNS 80
+#define VGA_ROWS 25
 #define VGA_START (uint16_t *)0x000b8000
-#define VGA_END (VGA_START + VGA_COLUMNS * 25)
+#define VGA_END (VGA_START + VGA_COLUMNS * VGA_ROWS)
 static uint16_t *cursor = VGA_START;
 static uint16_t mask;
 
@@ -25,7 +26,7 @@ void vga_blank() {
   uint32_t *p = (uint32_t *)VGA_START;
   while (p < (uint32_t *)VGA_END)
     *p++ = f;
-  cursor = VGA_START;
+  cursor = VGA_END - VGA_COLUMNS;
 }
 
 void vga_printch(char ch) {
@@ -37,4 +38,10 @@ void vga_printch(char ch) {
     *cursor++ = mask | (uint8_t)ch;
   if (cursor == VGA_END)
     vga_scroll();
+}
+
+void vga_print_at(uint16_t pos, const char *sz) {
+  cursor = VGA_START + (pos >> 8) * VGA_COLUMNS + (pos & 0xff);
+  while (*sz)
+    vga_printch(*sz++);
 }
\ No newline at end of file
diff --git a/src/kernel/vga.h b/src/kernel/vga.h
index bfc9fe6..fa97e11 100644
--- a/src/kernel/vga.h
+++ b/src/kernel/vga.h
@@ -3,6 +3,7 @@
 
 #include <stdint.h>
 
+void vga_print_at(uint16_t pos, const char *sz);
 void vga_set_color(uint8_t color);
 void vga_blank();
 void vga_printch(char ch);
diff --git a/src/user/dirinfo/dirinfo.c b/src/user/dirinfo/dirinfo.c
index 7484eb8..21afcc7 100644
--- a/src/user/dirinfo/dirinfo.c
+++ b/src/user/dirinfo/dirinfo.c
@@ -13,7 +13,7 @@ void main(const char *arg) {
   tell_user_sz(*arg ? arg : "drive root");
   tell_user_sz("\n");
 
-  _dir_info_entry infos[MAX_DIR_ENTRIES];
+  _dir_info_entry_t infos[MAX_DIR_ENTRIES];
   uint8_t count = _enumerate_dir(dn, path, infos, MAX_DIR_ENTRIES);
   tell_user_sz(
     count == MAX_DIR_ENTRIES
diff --git a/src/user/fileman/fileman.c b/src/user/fileman/fileman.c
new file mode 100644
index 0000000..0b28d1d
--- /dev/null
+++ b/src/user/fileman/fileman.c
@@ -0,0 +1,130 @@
+#include <pland/syscall.h>
+#include <knob/block.h>
+#include <knob/file.h>
+#include <knob/heap.h>
+#include <knob/task.h>
+
+char path_sz[1024] = "";
+uint32_t path_len = 0;
+
+_dir_info_entry_t *dir_info;
+uint32_t dir_info_len;
+
+uint32_t scroll;
+uint32_t selected;
+#define MAX_PER_SCREEN 18
+
+void paint_screen() {
+  _clear_screen();
+
+  _set_color(0x70);
+  _print_at(0, 0, path_sz);
+  _log_string("/");
+  _set_color(0x07);
+
+  for (uint32_t i = scroll, row = 2; (i < dir_info_len) && (row < MAX_PER_SCREEN + 2); ++i, ++row) {
+    if (i == selected)
+      _set_color(0x17);
+    _print_at(row, 0, dir_info[i].name);
+    if (dir_info[i].is_dir)
+      _log_string("/");
+    if (i == selected)
+      _set_color(0x07);
+  }
+
+  _print_at(21, 0, "keybindings:\n"
+                   "UP, DOWN, PAGE UP, PAGE DOWN, HOME, END: move selection\n"
+                   "ENTER: enter selected directory, run selected program\n"
+                   "ESC:   go up a directory   Q: quit");
+}
+
+void load_dir() {
+  free_block(dir_info);
+  dir_info = get_directory_info(path_sz, &dir_info_len);
+  scroll = 0;
+  selected = 0;
+}
+
+void main(const char *sz) {
+  path_len = strcpy(path_sz, sz);
+  dir_info = get_directory_info(sz, &dir_info_len);
+
+  paint_screen();
+
+  while (true) {
+    _key_code_t key;
+    switch (key = _get_key()) {
+    case 0:
+      _yield_task();
+      continue;
+    case '\n':
+      {
+      uint32_t old_len = path_len;
+      if (path_len)
+        path_sz[path_len++] = '/';
+      path_len += strcpy(path_sz + path_len, dir_info[selected].name);
+      if (dir_info[selected].is_dir)
+        load_dir();
+      else {
+        try_run_command_blocking(path_sz);
+        //TODO: handle error
+        path_sz[old_len] = '\0';
+        path_len = old_len;
+      }
+      }
+      break;
+    case _KEY_ESC:
+      {
+      char *cutoff = path_sz;
+      for (char *i = path_sz + path_len - 1; i >= path_sz; --i)
+        if (*i == '/') {
+          cutoff = i;
+          break;
+        }
+      *cutoff = '\0';
+      path_len = cutoff - path_sz;
+      load_dir();
+      }
+      break;
+    case _KEY_HOME:
+      scroll = 0;
+      selected = 0;
+      break;
+    case _KEY_END:
+      selected = dir_info_len - 1;
+      scroll = dir_info_len >= MAX_PER_SCREEN
+        ? dir_info_len - MAX_PER_SCREEN : 0;
+      break;
+    case _KEY_UP:
+      if (!selected)
+        continue;
+      if (--selected < scroll)
+        scroll = selected;
+      break;
+    case _KEY_DOWN:
+      if (selected == dir_info_len - 1)
+        continue;
+      if (++selected >= scroll + MAX_PER_SCREEN)
+        ++scroll;
+      break;
+    case _KEY_PUP:
+      selected = selected >= MAX_PER_SCREEN
+        ? selected - MAX_PER_SCREEN : 0;
+      scroll = scroll >= MAX_PER_SCREEN
+        ? scroll - MAX_PER_SCREEN : 0;
+      break;
+    case _KEY_PDOWN:
+      if ((selected += MAX_PER_SCREEN) >= dir_info_len)
+        selected = dir_info_len - 1;
+      if ((scroll += MAX_PER_SCREEN) > selected)
+        scroll = selected;
+      break;
+    case 'q':
+      _clear_screen();
+      return;
+    default:
+      continue;
+    }
+    paint_screen();
+  }
+}
\ No newline at end of file
diff --git a/src/user/highway/line.c b/src/user/highway/line.c
index ca38c9b..40dccfa 100644
--- a/src/user/highway/line.c
+++ b/src/user/highway/line.c
@@ -1,5 +1,5 @@
+#include <pland/pcrt.h>
 #include <knob/block.h>
-#include <knob/quit.h>
 #include <knob/task.h>
 #include <knob/user.h>
 #include "cmds.h"
@@ -68,7 +68,7 @@ void run_line(const char *original_line) {
   else if (blockequ(line, "vars", space - line))
     dump_vars();
   else if (blockequ(line, "quit", space - line))
-    quit(space + 1);
+    __pcrt_quit();
   else if (blockequ(line, "help", space - line))
     tell_user_sz("Highway is a command shell for Portland OS. It includes variables and a couple\n"
                  "of pseudo-commands. Variables are addressed by surrounding with \"$\". The\n"
@@ -78,7 +78,7 @@ void run_line(const char *original_line) {
                  "  echo STRING       print STRING\n"
                  "  vars              dump variables\n"
                  "  quit              exit highway\n"
-                 "  help              show this\n\n");
+                 "  help              show this\n");
   else if (!try_run_command_blocking(line)) {
     struct no_null_sn arg = {
       .data = "_path",
diff --git a/src/user/highway/main.c b/src/user/highway/main.c
index 1934920..61f736e 100644
--- a/src/user/highway/main.c
+++ b/src/user/highway/main.c
@@ -9,7 +9,7 @@ void main(const char *arg) {
   yield_task();
   tell_user_sz("Portland Highway\nType \"help\" for help.\n");
   while (1) {
-    tell_user_sz("> ");
+    tell_user_sz("\n> ");
     ask_user_line_sz(cmd_buf, 127);
     run_line(cmd_buf);
   }
diff --git a/src/user/include/knob/block.h b/src/user/include/knob/block.h
index 4625577..43137e1 100644
--- a/src/user/include/knob/block.h
+++ b/src/user/include/knob/block.h
@@ -7,4 +7,7 @@
 void blockcpy(void *to, const void *from, uint32_t size);
 bool blockequ(const void *a, const void *b, uint32_t size) __attribute__ ((__pure__));
 
+//returns length without null-terminator
+uint32_t strcpy(char *to, const char *from);
+
 #endif
\ No newline at end of file
diff --git a/src/user/include/knob/file.h b/src/user/include/knob/file.h
index a0d084f..8862098 100644
--- a/src/user/include/knob/file.h
+++ b/src/user/include/knob/file.h
@@ -2,6 +2,7 @@
 #define KNOB_FILE_H
 
 #include <stdint.h>
+#include <pland/syscall.h>
 
 struct file;
 
@@ -9,7 +10,6 @@ const char *remove_prefix(const char *path, uint8_t *dn_out);
 
 struct file *open_file(const char *path);
 void close_file(struct file *f);
-void _close_all_files();
 
 uint32_t read_from_file(struct file *f, uint32_t max, void *buf);
 //return value and max_length don't include null terminator
@@ -19,4 +19,7 @@ int32_t seek_file_by(struct file *f, int32_t by);
 
 uint32_t file_size(struct file *f) __attribute__ ((pure));
 
+//return value must be manually freed, unless it is a null pointer
+_dir_info_entry_t *get_directory_info(const char *path, uint32_t *count_out);
+
 #endif
\ No newline at end of file
diff --git a/src/user/include/knob/quit.h b/src/user/include/knob/quit.h
deleted file mode 100644
index 7b10d09..0000000
--- a/src/user/include/knob/quit.h
+++ /dev/null
@@ -1,7 +0,0 @@
-#ifndef KNOB_QUIT_H
-#define KNOB_QUIT_H
-
-void on_quit(void (*run_f)());
-void quit() __attribute__ ((noreturn));
-
-#endif
\ No newline at end of file
diff --git a/src/user/include/knob/user.h b/src/user/include/knob/user.h
index 479a731..cd7676c 100644
--- a/src/user/include/knob/user.h
+++ b/src/user/include/knob/user.h
@@ -2,6 +2,9 @@
 #define KNOB_USER_H
 
 #include <stdint.h>
+#include <pland/syscall.h>
+
+char key_to_char(_key_code_t key) __attribute__ ((const));
 
 void tell_user_sz(const char *sz);
 
diff --git a/src/user/include/pland/pcrt.h b/src/user/include/pland/pcrt.h
new file mode 100644
index 0000000..07ad453
--- /dev/null
+++ b/src/user/include/pland/pcrt.h
@@ -0,0 +1,16 @@
+#ifndef PLAND_PCRT_H
+#define PLAND_PCRT_H
+
+#define BEFORE_MAIN(f) \
+  __attribute__ ((section (".__pcrt_before_main"))) \
+  __attribute__ ((unused)) \
+  void (*const __pcrt_bm_##f)() = &f;
+
+#define BEFORE_QUIT(f) \
+  __attribute__ ((section (".__pcrt_before_quit"))) \
+  __attribute__ ((unused)) \
+  void (*const __pcrt_bq_##f)() = &f;
+
+void __pcrt_quit() __attribute__ ((noreturn));
+
+#endif
\ No newline at end of file
diff --git a/src/user/include/pland/syscall.h b/src/user/include/pland/syscall.h
index e16a7fb..331002e 100644
--- a/src/user/include/pland/syscall.h
+++ b/src/user/include/pland/syscall.h
@@ -7,14 +7,9 @@
 typedef uint32_t _file_handle_t;
 typedef uint32_t _task_handle_t;
 typedef uint32_t _drive_number_t;
-typedef uint32_t _pages_t;
 typedef uint32_t _process_handle_t;
 
 typedef enum {
-  _KEY_BACKSPACE = '\b',
-  _KEY_RETURN    = '\n',
-  //etc.
-
   _KEY_LSHIFT = 0x00000100,
   _KEY_RSHIFT = 0x00000200,
   _KEY_CAPS   = 0x00000400,
@@ -33,8 +28,103 @@ typedef enum {
   _KEY_ALT    = 0x0000c000,
   _KEY_CTRL   = 0x00030000,
   _KEY_META   = 0x000c0000,
+
+  _KEY_BEGIN_CAPS = 0x80,
+  _KEY_BEGIN_INSERT,
+  _KEY_BEGIN_NUM,
+  _KEY_BEGIN_SCROLL,
+  _KEY_BEGIN_LSHIFT,
+  _KEY_BEGIN_RSHIFT,
+  _KEY_BEGIN_LALT,
+  _KEY_BEGIN_RALT,
+  _KEY_BEGIN_LCTRL,
+  _KEY_BEGIN_RCTRL,
+  _KEY_BEGIN_LMETA,
+  _KEY_BEGIN_RMETA,
+  /* 0x8c - 0x97 reserved */
+  /* 0x98 - 0x9f unassigned */
+  _KEY_F1 = 0xa0,
+  _KEY_F2,
+  _KEY_F3,
+  _KEY_F4,
+  _KEY_F5,
+  _KEY_F6,
+  _KEY_F7,
+  _KEY_F8,
+  _KEY_F9,
+  _KEY_F10,
+  _KEY_F11,
+  _KEY_F12,
+  /* 0xac - 0xaf unassigned */
+  _KEY_NUM0 = 0xb0,
+  _KEY_NUM1,
+  _KEY_NUM2,
+  _KEY_NUM3,
+  _KEY_NUM4,
+  _KEY_NUM5,
+  _KEY_NUM6,
+  _KEY_NUM7,
+  _KEY_NUM8,
+  _KEY_NUM9,
+  _KEY_NTIMES,
+  _KEY_NPLUS,
+  _KEY_NENTER,
+  _KEY_NMINUS,
+  _KEY_NDOT,
+  _KEY_NSLASH,
+  /* 0xc0 unassigned */
+  _KEY_DELETE,
+  _KEY_HOME,
+  _KEY_END,
+  _KEY_PUP,
+  _KEY_PDOWN,
+  _KEY_UP,
+  _KEY_DOWN,
+  _KEY_LEFT,
+  _KEY_RIGHT,
+  _KEY_ESC,
+  _KEY_MENU,
+  _KEY_PAUSE,
+  _KEY_PRSCR,
+  /* 0xce - 0xef unassigned */
 } _key_code_t;
 
+typedef enum {
+  _COLOR_FG_BLACK   = 0x00,
+  _COLOR_FG_BLUE    = 0x01,
+  _COLOR_FG_GREEN   = 0x02,
+  _COLOR_FG_CYAN    = 0x03,
+  _COLOR_FG_RED     = 0x04,
+  _COLOR_FG_MAGENTA = 0x05,
+  _COLOR_FG_BROWN   = 0x06,
+  _COLOR_FG_LGRAY   = 0x07,
+
+  _COLOR_FG_DGRAY   = 0x08,
+  _COLOR_FG_LBLUE   = 0x09,
+  _COLOR_FG_LGREEN  = 0x0a,
+  _COLOR_FG_LCYAN   = 0x0b,
+  _COLOR_FG_LRED    = 0x0c,
+  _COLOR_FG_PINK    = 0x0d,
+  _COLOR_FG_YELLOW  = 0x0e,
+  _COLOR_FG_WHITE   = 0x0f,
+
+  _COLOR_BG_BLACK   = 0x00,
+  _COLOR_BG_BLUE    = 0x10,
+  _COLOR_BG_GREEN   = 0x20,
+  _COLOR_BG_CYAN    = 0x30,
+  _COLOR_BG_RED     = 0x40,
+  _COLOR_BG_MAGENTA = 0x50,
+  _COLOR_BG_BROWN   = 0x60,
+  _COLOR_BG_LGRAY   = 0x70
+} _vga_color_t;
+
+typedef struct __attribute__ ((packed)) {
+  char name[100];
+  uint32_t size;
+  bool is_dir;
+  uint8_t pad[23];
+} _dir_info_entry_t;
+
 enum _scn {
   _SCN_OPEN_FILE,
   _SCN_CLOSE_FILE,
@@ -46,72 +136,74 @@ enum _scn {
   _SCN_ALLOCATE_RAM,
   _SCN_MEMORY_INFO,
   _SCN_WAIT_FOR_TASK,
-  _SCN_ENUMERATE_DIR
+  _SCN_ENUMERATE_DIR,
+  _SCN_PRINT_AT,
+  _SCN_COUNT_OF_DIR,
+  _SCN_CLEAR_SCREEN,
+  _SCN_SET_COLOR
 };
 
-typedef struct {
-  bool is_dir;
-  char name[100];
-  uint32_t size;
-} _dir_info_entry;
-
 static inline uint32_t _sc0(enum _scn eax) {
-  volatile uint32_t out;
-  asm (
+  uint32_t out;
+  asm volatile (
     "int $0x30"
   : "=a" (out) : "a" (eax) : "ecx", "edx");
   return out;
 }
 
 static inline uint32_t _sc1(enum _scn eax, uint32_t ebx) {
-  volatile uint32_t out;
-  asm (
+  uint32_t out;
+  asm volatile (
     "int $0x30"
   : "=a" (out) : "a" (eax), "b" (ebx) : "ecx", "edx");
   return out;
 }
 
 static inline uint32_t _sc2(enum _scn eax, uint32_t ebx, uint32_t ecx) {
-  volatile uint32_t out;
-  asm (
+  uint32_t out;
+  uint32_t dummy;
+  asm volatile (
     "int $0x30"
-  : "=a" (out) : "a" (eax), "b" (ebx), "c" (ecx) : "edx");
+  : "=a" (out), "=c" (dummy) : "a" (eax), "b" (ebx), "c" (ecx) : "edx");
   return out;
 }
 
 static inline uint32_t _sc3(enum _scn eax, uint32_t ebx, uint32_t ecx, uint32_t edx) {
-  volatile uint32_t out;
-  asm (
+  uint32_t out;
+  uint32_t dummy;
+  asm volatile (
     "int $0x30"
-  : "=a" (out) : "a" (eax), "b" (ebx), "c" (ecx), "d" (edx));
+  : "=a" (out), "=c" (dummy), "=d" (dummy) : "a" (eax), "b" (ebx), "c" (ecx), "d" (edx));
   return out;
 }
 
 static inline uint32_t _sc4(enum _scn eax, uint32_t ebx, uint32_t ecx, uint32_t edx, uint32_t esi) {
-  volatile uint32_t out;
-  asm (
+  uint32_t out;
+  uint32_t dummy;
+  asm volatile (
     "int $0x30"
-  : "=a" (out) : "a" (eax), "b" (ebx), "c" (ecx), "d" (edx), "S" (esi));
+  : "=a" (out), "=c" (dummy), "=d" (dummy) : "a" (eax), "b" (ebx), "c" (ecx), "d" (edx), "S" (esi));
   return out;
 }
 
 static inline uint32_t _sc5(enum _scn eax, uint32_t ebx, uint32_t ecx, uint32_t edx, uint32_t esi, uint32_t edi) {
-  volatile uint32_t out;
-  asm (
+  uint32_t out;
+  uint32_t dummy;
+  asm volatile (
     "int $0x30"
-  : "=a" (out) : "a" (eax), "b" (ebx), "c" (ecx), "d" (edx), "S" (esi), "D" (edi));
+  : "=a" (out), "=c" (dummy), "=d" (dummy) : "a" (eax), "b" (ebx), "c" (ecx), "d" (edx), "S" (esi), "D" (edi));
   return out;
 }
 
 static inline void _yield_task() {
-  asm (
+  asm volatile (
     "int $0x39"
   : : : "eax");
 }
 
 __attribute__ ((noreturn))
 static inline void _exit_task() {
-  asm (
+  asm volatile (
     "int $0x38"
   );
   __builtin_unreachable();
@@ -145,27 +237,27 @@ static inline _key_code_t _get_key() {
   return _sc0(_SCN_GET_KEY);
 }
 
-static inline void *_allocate_ram(_pages_t pages) {
+static inline void *_allocate_ram(uint32_t pages) {
   return (void *)_sc1(_SCN_ALLOCATE_RAM, pages);
 }
 
-static inline _pages_t _kernel_dynamic_area_size() {
+static inline uint32_t _kernel_dynamic_area_size() {
   return _sc1(_SCN_MEMORY_INFO, 0x0);
 }
 
-static inline _pages_t _kernel_dynamic_area_left() {
+static inline uint32_t _kernel_dynamic_area_left() {
   return _sc1(_SCN_MEMORY_INFO, 0x1);
 }
 
-static inline _pages_t _total_userspace_size() {
+static inline uint32_t _total_userspace_size() {
   return _sc1(_SCN_MEMORY_INFO, 0x2);
 }
 
-static inline _pages_t _total_userspace_left() {
+static inline uint32_t _total_userspace_left() {
   return _sc1(_SCN_MEMORY_INFO, 0x3);
 }
 
-static inline _pages_t _this_process_memory_left() {
+static inline uint32_t _this_process_memory_left() {
   return _sc1(_SCN_MEMORY_INFO, 0x4);
 }
 
@@ -173,8 +265,24 @@ static inline void _wait_for_task(_process_handle_t handle) {
   _sc1(_SCN_WAIT_FOR_TASK, handle);
 }
 
-static inline uint32_t _enumerate_dir(_drive_number_t drive_number, const char *path, _dir_info_entry *buffer, uint32_t max_count) {
+static inline uint32_t _enumerate_dir(_drive_number_t drive_number, const char *path, _dir_info_entry_t *buffer, uint32_t max_count) {
   return _sc4(_SCN_ENUMERATE_DIR, drive_number, (uint32_t)path, (uint32_t)buffer, max_count);
 }
 
+static inline void _print_at(uint8_t row, uint8_t col, const char *sz) {
+  _sc2(_SCN_PRINT_AT, (row << 8) | col, (uint32_t)sz);
+}
+
+static inline uint32_t _count_of_dir(uint8_t drive_number, const char *path) {
+  return _sc2(_SCN_COUNT_OF_DIR, drive_number, (uint32_t)path);
+}
+
+static inline void _clear_screen() {
+  _sc0(_SCN_CLEAR_SCREEN);
+}
+
+static inline void _set_color(_vga_color_t color) {
+  _sc1(_SCN_SET_COLOR, color);
+}
+
 #endif
\ No newline at end of file
diff --git a/src/user/knob/block.c b/src/user/knob/block.c
index 7524ad3..4ec0564 100644
--- a/src/user/knob/block.c
+++ b/src/user/knob/block.c
@@ -14,4 +14,13 @@ bool blockequ(const void *a, const void *b, uint32_t size) {
     if (*(uint8_t *)(a++) != *(uint8_t *)(b++))
       return false;
   return true;
+}
+
+//returns length without null-terminator
+uint32_t strcpy(char *to, const char *from) {
+  uint32_t i = 0;
+  do
+    to[i] = from[i];
+  while (from[i++]);
+  return i - 1;
 }
\ No newline at end of file
diff --git a/src/user/knob/entry.asm b/src/user/knob/entry.asm
deleted file mode 100644
index e9548d4..0000000
--- a/src/user/knob/entry.asm
+++ /dev/null
@@ -1,23 +0,0 @@
-bits 32
-
-global _entry
-
-extern main
-extern quit
-
-extern current_disk
-
-section .text
-_entry:
-  mov esp, stack
-  push edx
-
-  ;TODO: determine current_disk
-  ;any further needed initialization
-
-  push quit
-  jmp main
-
-section .stack nobits alloc noexec write align=16
-resb 4096
-stack:
\ No newline at end of file
diff --git a/src/user/knob/file.c b/src/user/knob/file.c
index 23b7564..f1a039d 100644
--- a/src/user/knob/file.c
+++ b/src/user/knob/file.c
@@ -1,4 +1,5 @@
 #include <pland/syscall.h>
+#include <pland/pcrt.h>
 #include <knob/format.h>
 #include <knob/heap.h>
 #include <knob/env.h>
@@ -11,11 +12,13 @@ struct ofl_node {
 
 static struct ofl_node *head_ofl_node = 0;
 
-void _close_all_files() {
+static void _close_all_files() {
   for (struct ofl_node *i = head_ofl_node; i; i = i->next)
     _close_file(i->handle);
 }
 
+BEFORE_QUIT(_close_all_files)
+
 struct file {
   struct ofl_node *node;
   _file_handle_t handle;
@@ -121,4 +124,20 @@ int32_t seek_file_by(struct file *f, int32_t by) {
 __attribute__ ((pure))
 uint32_t file_size(struct file *f) {
   return f->length;
+}
+
+//return value must be manually freed, unless it is a null pointer
+_dir_info_entry_t *get_directory_info(const char *path, uint32_t *count_out) {
+  uint8_t dn;
+  path = remove_prefix(path, &dn);
+
+  uint32_t count = _count_of_dir(dn, path);
+  if (!count) {
+    *count_out = 0;
+    return 0;
+  }
+
+  _dir_info_entry_t *buffer = get_block(count * sizeof(_dir_info_entry_t));
+  *count_out = _enumerate_dir(dn, path, buffer, count);
+  return buffer;
 }
\ No newline at end of file
diff --git a/src/user/knob/quit.c b/src/user/knob/quit.c
deleted file mode 100644
index 98881b7..0000000
--- a/src/user/knob/quit.c
+++ /dev/null
@@ -1,8 +0,0 @@
-#include <pland/syscall.h>
-#include <knob/file.h>
-
-__attribute__ ((noreturn))
-void quit() {
-  _close_all_files();
-  _exit_task();
-}
\ No newline at end of file
diff --git a/src/user/knob/user.c b/src/user/knob/user.c
index b642f79..dfcb791 100644
--- a/src/user/knob/user.c
+++ b/src/user/knob/user.c
@@ -116,10 +116,8 @@ static const uint8_t shifted[] = {
   0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00
 };
 
-static char get_key_char() {
-  _key_code_t key;
-  while (!(key = _get_key()))
-    _yield_task();
+__attribute__ ((const))
+char key_to_char(_key_code_t key) {
   return
     key & _KEY_CAPS
     ? key & _KEY_SHIFT
@@ -130,6 +128,13 @@ static char get_key_char() {
       : key & 0xff;
 }
 
+static char get_key_char() {
+  _key_code_t key;
+  while (!(key = _get_key()))
+    _yield_task();
+  return key_to_char(key);
+}
+
 void tell_user_sz(const char *sz) {
   _log_string(sz);
 }
diff --git a/src/user/elf.ld b/src/user/runtimes/asm/elf.ld
index aaef517..aaef517 100644
--- a/src/user/elf.ld
+++ b/src/user/runtimes/asm/elf.ld
diff --git a/src/user/runtimes/c/elf.ld b/src/user/runtimes/c/elf.ld
new file mode 100644
index 0000000..f321be2
--- /dev/null
+++ b/src/user/runtimes/c/elf.ld
@@ -0,0 +1,22 @@
+OUTPUT_FORMAT(elf32-i386)
+OUTPUT_ARCH(i386)
+ENTRY(__pcrt_entry)
+
+MEMORY {
+  kernel (!a) : ORIGIN = 0x00000000, LENGTH = 0x08000000
+  user  (awx) : ORIGIN = 0x08000000, LENGTH = 0xf8000000
+}
+
+SECTIONS {
+  .__pcrt_before_main : {
+    __pcrt_before_main_start = .;
+    *(.__pcrt_before_main)
+    __pcrt_before_main_end = .;
+  }
+
+  .__pcrt_before_quit : {
+    __pcrt_before_quit_start = .;
+    *(.__pcrt_before_quit)
+    __pcrt_before_quit_end = .;
+  }
+}
\ No newline at end of file
diff --git a/src/user/runtimes/c/entry.asm b/src/user/runtimes/c/entry.asm
new file mode 100644
index 0000000..bba8060
--- /dev/null
+++ b/src/user/runtimes/c/entry.asm
@@ -0,0 +1,42 @@
+bits 32
+
+global __pcrt_entry
+global __pcrt_quit
+
+extern main
+extern __pcrt_before_main_start
+extern __pcrt_before_main_end
+extern __pcrt_before_quit_start
+extern __pcrt_before_quit_end
+
+section .text
+__pcrt_entry:
+  mov esp, stack
+  push edx
+
+  mov ebx, __pcrt_before_main_start
+.before_main_loop:
+  cmp ebx, __pcrt_before_main_end
+  je .call_main
+  call dword [ebx]
+  add ebx, 4
+  jmp .before_main_loop
+
+.call_main:
+  call main
+
+__pcrt_quit:
+  mov ebx, __pcrt_before_quit_start
+.before_quit_loop:
+  cmp ebx, __pcrt_before_quit_end
+  je .end_task
+  call dword [ebx]
+  add ebx, 4
+  jmp .before_quit_loop
+
+.end_task:
+  int 0x38
+
+section .stack nobits alloc noexec write align=16
+resb 4096
+stack:
\ No newline at end of file