21 files changed, 635 insertions, 204 deletions

diff --git a/src/user/elf.ld b/src/user/elf.ld
new file mode 100644
index 0000000..aaef517
--- /dev/null
+++ b/src/user/elf.ld
@@ -0,0 +1,8 @@
+OUTPUT_FORMAT(elf32-i386)
+OUTPUT_ARCH(i386)
+ENTRY(_entry)
+
+MEMORY {
+  kernel (!a) : ORIGIN = 0x00000000, LENGTH = 0x08000000
+  user  (awx) : ORIGIN = 0x08000000, LENGTH = 0xf8000000
+}
\ No newline at end of file
diff --git a/src/user/hello/hello.asm b/src/user/hello/hello.asm
deleted file mode 100644
index 345abb4..0000000
--- a/src/user/hello/hello.asm
+++ /dev/null
@@ -1,15 +0,0 @@
-global _entry
-
-section .text
-_entry:
-  mov eax, 3
-  mov ebx, msg
-  int 0x32
-
-  int 0x30
-
-section .rodata
-msg db "Hello, world!", 0x0a, 0x00
-
-section .bss
-stack resb 8
\ No newline at end of file
diff --git a/src/user/include/canyo/file.h b/src/user/include/canyo/file.h
deleted file mode 100644
index 5f09387..0000000
--- a/src/user/include/canyo/file.h
+++ /dev/null
@@ -1,9 +0,0 @@
-#ifndef CANYO_FILE_H
-#define CANYO_FILE_H
-
-#include <stdint.h>
-#include <pland.h>
-
-uint32_t read_line(fs_handle handle, uint32_t max_length, void *buffer);
-
-#endif
\ No newline at end of file
diff --git a/src/user/include/knob/block.h b/src/user/include/knob/block.h
new file mode 100644
index 0000000..53b3deb
--- /dev/null
+++ b/src/user/include/knob/block.h
@@ -0,0 +1,8 @@
+#ifndef KNOB_BLOCK_H
+#define KNOB_BLOCK_H
+
+#include <stdint.h>
+
+void blockcpy(void *to, const void *from, uint32_t count);
+
+#endif
\ No newline at end of file
diff --git a/src/user/include/knob/env.h b/src/user/include/knob/env.h
new file mode 100644
index 0000000..6d750ae
--- /dev/null
+++ b/src/user/include/knob/env.h
@@ -0,0 +1,9 @@
+#ifndef KNOB_ENV_H
+#define KNOB_ENV_H
+
+#include <stdint.h>
+
+//not implemented yet
+extern uint32_t current_drive;
+
+#endif
\ No newline at end of file
diff --git a/src/user/include/knob/file.h b/src/user/include/knob/file.h
new file mode 100644
index 0000000..6068077
--- /dev/null
+++ b/src/user/include/knob/file.h
@@ -0,0 +1,17 @@
+#ifndef KNOB_FILE_H
+#define KNOB_FILE_H
+
+#include <stdint.h>
+
+struct file;
+
+struct file *open_file(const char *path);
+void close_file(struct file *f);
+
+uint32_t read_from_file(struct file *f, uint32_t max, void *buf);
+uint32_t seek_file_to(struct file *f, uint32_t to);
+int32_t seek_file_by(struct file *f, int32_t by);
+
+uint32_t file_size(struct file *f) __attribute__ ((pure));
+
+#endif
\ No newline at end of file
diff --git a/src/user/include/knob/format.h b/src/user/include/knob/format.h
new file mode 100644
index 0000000..16d3d83
--- /dev/null
+++ b/src/user/include/knob/format.h
@@ -0,0 +1,9 @@
+#ifndef KNOB_FORMAT_H
+#define KNOB_FORMAT_H
+
+#include <stdbool.h>
+#include <stdint.h>
+
+bool try_sntoi(const char *s, uint32_t n, uint32_t *out);
+
+#endif
\ No newline at end of file
diff --git a/src/user/include/knob/heap.h b/src/user/include/knob/heap.h
new file mode 100644
index 0000000..32dc44c
--- /dev/null
+++ b/src/user/include/knob/heap.h
@@ -0,0 +1,9 @@
+#ifndef KNOB_HEAP_H
+#define KNOB_HEAP_H
+
+#include <stdint.h>
+
+void *get_block(uint32_t bytes) __attribute__ ((malloc));
+void free_block(void *block);
+
+#endif
\ No newline at end of file
diff --git a/src/user/include/knob/quit.h b/src/user/include/knob/quit.h
new file mode 100644
index 0000000..7b10d09
--- /dev/null
+++ b/src/user/include/knob/quit.h
@@ -0,0 +1,7 @@
+#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
new file mode 100644
index 0000000..c4ec7db
--- /dev/null
+++ b/src/user/include/knob/user.h
@@ -0,0 +1,12 @@
+#ifndef KNOB_USER_H
+#define KNOB_USER_H
+
+#include <stdint.h>
+
+void tell_user_sz(const char *sz);
+void tell_user_n(uint32_t n);
+
+//return value and max_length both include null terminator
+uint32_t ask_user_line_sz(char *sz, uint32_t max_length);
+
+#endif
\ No newline at end of file
diff --git a/src/user/include/pland.h b/src/user/include/pland.h
deleted file mode 100644
index f174a51..0000000
--- a/src/user/include/pland.h
+++ /dev/null
@@ -1,157 +0,0 @@
-#ifndef PLAND_H
-#define PLAND_H
-
-#include <stdint.h>
-#include <stdbool.h>
-
-typedef uint8_t fs_handle;
-typedef uint8_t task_handle;
-
-static inline void exit() __attribute__ ((noreturn)) {
-  asm volatile ("int $0x30");
-  __builtin_unreachable();
-}
-
-static inline void yield() {
-  asm volatile ("int $0x31");
-}
-
-static inline uint32_t data_extend(uint32_t amount) {
-  uint32_t actual_amount;
-  asm volatile (
-    "int $0x33"
-  : "eax" (actual_amount) : "eax" (amount));
-  return actual_amount;
-}
-
-static inline void vga_blank() {
-  asm volatile (
-    "xor %%eax, %%eax\n"
-    "int $0x32"
-  : : : "eax");
-}
-
-static inline void vga_set_color(uint8_t color) {
-  asm volatile (
-    "mov $0x1, %%eax\n"
-    "int $0x32"
-  : : "ebx" (color) : "eax");
-}
-
-static inline void vga_printch(uint8_t ch) {
-  asm volatile (
-    "mov $0x2, %%eax\n"
-    "int $0x32"
-  : : "ebx" (ch) : "eax");
-}
-
-static inline void vga_printsz(uint8_t *sz) {
-  asm volatile (
-    "mov $0x3, %%eax\n"
-    "int $0x32"
-  : : "ebx" (sz) : "eax");
-}
-
-static inline void vga_printsn(uint8_t *sn, uint8_t length) {
-  asm volatile (
-    "mov $0x4, %%eax\n"
-    "int $0x32"
-  : : "ebx" (sn), "ecx" (length) : "eax");
-}
-
-static inline fs_handle fs_open(uint8_t *path) {
-  fs_handle handle;
-  asm volatile (
-    "mov $0x5, %%eax\n"
-    "int $0x32"
-  : "eax" (handle) : "ebx" (path));
-  return handle;
-}
-
-static inline fs_handle fs_open_root() {
-  fs_handle handle;
-  asm volatile (
-    "mov $0x6, %%eax\n"
-    "int $0x32"
-  : "eax" (handle));
-  return handle;
-}
-
-static inline fs_handle fs_new(uint8_t *path) {
-  fs_handle handle;
-  asm volatile (
-    "mov $0x7, %%eax\n"
-    "int $0x32"
-  : "eax" (handle) : "ebx" (path));
-  return handle;
-}
-
-static inline void fs_close(fs_handle handle) {
-  asm volatile (
-    "mov $0x8, %%eax\n"
-    "int $0x32"
-  : : "ebx" (handle) : "eax");
-}
-
-static inline void fs_delete(uint8_t *path) {
-  asm volatile (
-    "mov $0x9, %%eax\n"
-    "int $0x32"
-  : : "ebx" (path) : "eax");
-}
-
-static inline bool fs_exists(uint8_t *path) {
-  bool does;
-  asm volatile (
-    "mov $0xa, %%eax\n"
-    "int $0x32"
-  : "eax" (does) : "ebx" (path));
-  return does;
-}
-
-static inline int32_t fs_seek(fs_handle handle, int32_t by) {
-  int32_t seeked_by;
-  asm volatile (
-    "mov $0xb, %%eax\n"
-    "int $0x32"
-  : "eax" (seeked_by) : "ebx" (handle), "ecx" (by));
-  return seeked_by;
-}
-
-static inline uint32_t fs_tell(fs_handle handle) {
-  uint32_t position;
-  asm volatile (
-    "mov $0xc, %%eax\n"
-    "int $0x32"
-  : "eax" (position) : "ebx" (handle));
-  return position;
-}
-
-static inline uint32_t fs_read(fs_handle handle, uint32_t max, void *buffer) {
-  uint32_t read;
-  asm volatile (
-    "mov %0xd, %%eax\n"
-    "int $0x32"
-  : "eax" (read) : "ebx" (handle), "ecx" (max), "edx" (buffer) : "memory");
-  return read;
-}
-
-static inline uint32_t fs_write(fs_handle handle, uint32_t max, void *buffer) {
-  uint32_t written;
-  asm volatile (
-    "mov %0xe, %%eax\n"
-    "int $0x32"
-  : "eax" (written) : "ebx" (handle), "ecx" (max), "edx" (buffer));
-  return written;
-}
-
-static inline task_handle plef_run(uint8_t *image_path) {
-  task_handle handle;
-  asm volatile (
-    "mov %0xf, %%eax\n"
-    "int $0x32"
-  : "eax" (handle) : "ebx" (image_path));
-  return handle;
-}
-
-#endif
diff --git a/src/user/include/pland/syscall.h b/src/user/include/pland/syscall.h
new file mode 100644
index 0000000..01f7151
--- /dev/null
+++ b/src/user/include/pland/syscall.h
@@ -0,0 +1,139 @@
+#ifndef PLAND_SYSCALL_H
+#define PLAND_SYSCALL_H
+
+#include <stdint.h>
+
+typedef uint32_t _file_handle_t;
+typedef uint32_t _task_handle_t;
+typedef uint32_t _drive_number_t;
+typedef enum {
+  _KEY_BACKSPACE = '\b',
+  _KEY_RETURN    = '\n',
+  //etc.
+
+  _KEY_LSHIFT = 0x00000100,
+  _KEY_RSHIFT = 0x00000200,
+  _KEY_CAPS   = 0x00000400,
+  _KEY_INSERT = 0x00000800,
+  _KEY_NUM    = 0x00001000,
+  _KEY_SCROLL = 0x00002000,
+  _KEY_LALT   = 0x00004000,
+  _KEY_RALT   = 0x00008000,
+  _KEY_LCTRL  = 0x00010000,
+  _KEY_RCTRL  = 0x00020000,
+  _KEY_LMETA  = 0x00040000,
+  _KEY_RMETA  = 0x00080000,
+
+  _KEY_SHIFT  = 0x00000300,
+  _KEY_SCAPS  = 0x00000700,
+  _KEY_ALT    = 0x0000c000,
+  _KEY_CTRL   = 0x00030000,
+  _KEY_META   = 0x000c0000,
+} _key_code_t;
+
+enum _scn {
+  _SCN_OPEN_FILE,
+  _SCN_CLOSE_FILE,
+  _SCN_FILE_READ,
+  _SCN_FILE_SIZE,
+  _SCN_START_TASK,
+  _SCN_LOG_STRING,
+  _SCN_GET_KEY,
+  _SCN_ALLOCATE_RAM
+};
+
+static inline uint32_t _sc0(enum _scn eax) {
+  volatile uint32_t out;
+  asm (
+    "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 (
+    "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 (
+    "int $0x30"
+  : "=a" (out) : "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 (
+    "int $0x30"
+  : "=a" (out) : "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 (
+    "int $0x30"
+  : "=a" (out) : "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 (
+    "int $0x30"
+  : "=a" (out) : "a" (eax), "b" (ebx), "c" (ecx), "d" (edx), "S" (esi), "D" (edi));
+  return out;
+}
+
+static inline void _yield_task() {
+  asm (
+    "int $0x39"
+  );
+}
+
+__attribute__ ((noreturn))
+static inline void _exit_task() {
+  asm (
+    "int $0x38"
+  );
+  __builtin_unreachable();
+}
+
+static inline _file_handle_t _open_file(_drive_number_t drive_number, const char *path) {
+  return _sc2(_SCN_OPEN_FILE, drive_number, (uint32_t)path);
+}
+
+static inline void _close_file(_file_handle_t handle) {
+  _sc1(_SCN_CLOSE_FILE, handle);
+}
+
+static inline uint32_t _file_read(_file_handle_t handle, uint32_t file_offset, uint32_t count, void *buffer) {
+  return _sc4(_SCN_FILE_READ, handle, file_offset, count, (uint32_t)buffer);
+}
+
+static inline uint32_t _file_size(_file_handle_t handle) {
+  return _sc1(_SCN_FILE_SIZE, handle);
+}
+
+static inline void _start_task(_drive_number_t drive_number, char *path) {
+  _sc2(_SCN_START_TASK, drive_number, (uint32_t)path);
+}
+
+static inline void _log_string(const char *sz) {
+  _sc1(_SCN_LOG_STRING, (uint32_t)sz);
+}
+
+static inline _key_code_t _get_key() {
+  return _sc0(_SCN_GET_KEY);
+}
+
+static inline void *_allocate_ram(uint32_t pages) {
+  return (void *)_sc1(_SCN_ALLOCATE_RAM, pages);
+}
+
+#endif
\ No newline at end of file
diff --git a/src/user/init/main.c b/src/user/init/main.c
index 002fd92..9a411e7 100644
--- a/src/user/init/main.c
+++ b/src/user/init/main.c
@@ -1,16 +1,29 @@
-#include <pland.h>
-#include <canyo/file.h>
+#include <knob/user.h>
+#include <knob/file.h>
+#include <knob/heap.h>
 
 void main() {
-  fs_handle f = fs_open("sys/startup.rc");
+  tell_user_sz("\n\nThis is a userland program.\n");
+
+  tell_user_sz("Opening sd0:TEST.TXT.\n");
+  struct file *f = open_file("sd0:TEST.TXT");
   if (!f) {
-    vga_printsz("Couldn't open sys/startup.rc\n");
+    tell_user_sz("Failed to open.\n");
     return;
   }
 
-  uint8_t line_buffer[128];
-  while (read_line(f, 128, line_buffer))
-    plef_run(line_buffer);
+  tell_user_sz("Length: ");
+  uint32_t size = file_size(f);
+  tell_user_n(size);
+  tell_user_sz(" bytes\n\nContents:\n");
+
+  char *buf = get_block(size + 1);
+  read_from_file(f, size, buf);
+  buf[size] = '\0';
+
+  close_file(f);
+
+  tell_user_sz(buf);
 
-  fs_close(f);
+  tell_user_sz("\n\nGoodbye!\n");
 }
diff --git a/src/user/knob/entry.asm b/src/user/knob/entry.asm
new file mode 100644
index 0000000..ae024c4
--- /dev/null
+++ b/src/user/knob/entry.asm
@@ -0,0 +1,23 @@
+bits 32
+
+global _entry
+
+extern main
+extern quit
+
+extern current_disk
+
+section .text
+_entry:
+  mov esp, stack
+
+  ;TODO: heap stuff?
+  ;TODO: determine current_disk
+  ;any further needed initialization
+
+  push quit
+  jmp main
+
+section .stack nobits alloc noexec write align=16
+resb 1024
+stack:
\ No newline at end of file
diff --git a/src/user/knob/env.c b/src/user/knob/env.c
new file mode 100644
index 0000000..952ab86
--- /dev/null
+++ b/src/user/knob/env.c
@@ -0,0 +1,3 @@
+#include <stdint.h>
+
+uint32_t current_drive;
\ No newline at end of file
diff --git a/src/user/knob/file.c b/src/user/knob/file.c
new file mode 100644
index 0000000..8ab7acd
--- /dev/null
+++ b/src/user/knob/file.c
@@ -0,0 +1,82 @@
+#include <pland/syscall.h>
+#include <knob/format.h>
+#include <knob/heap.h>
+#include <knob/env.h>
+
+struct file {
+  _file_handle_t handle;
+  uint32_t position;
+  uint32_t length;
+};
+
+static const char *try_remove_prefix(const char *path, uint8_t *dn_out) {
+  if ((path[0] != 's') || (path[1] != 'd'))
+    return 0;
+
+  const char *num_part = path + 2;
+  for (uint32_t i = 0; num_part[i]; ++i)
+    if (num_part[i] == ':') {
+
+      uint32_t dn_large;
+      if (!try_sntoi(num_part, i, &dn_large) || dn_large > 255)
+        return 0;
+
+      *dn_out = (uint8_t)dn_large;
+      return num_part + i + 1;
+    }
+
+  return 0;
+}
+
+struct file *open_file(const char *path) {
+  uint8_t dn;
+  const char *path_part = try_remove_prefix(path, &dn);
+  if (path_part)
+    path = path_part;
+  else
+    dn = current_drive;
+
+  _file_handle_t h = _open_file(dn, path);
+  if (!h)
+    return 0;
+
+  struct file *f = get_block(sizeof(struct file));
+  f->handle = h;
+  f->position = 0;
+  f->length = _file_size(h);
+
+  return f;
+}
+
+void close_file(struct file *f) {
+  _close_file(f->handle);
+  free_block(f);
+}
+
+uint32_t read_from_file(struct file *f, uint32_t max, void *buf) {
+  if (f->position + max > f->length)
+    max = f->length - f->position;
+
+  uint32_t read = _file_read(f->handle, f->position, max, buf);
+
+  f->position += read;
+  return read;
+}
+
+uint32_t seek_file_to(struct file *f, uint32_t to) {
+  if (to > f->length)
+    to = f->length;
+  return f->position = to;
+}
+
+int32_t seek_file_by(struct file *f, int32_t by) {
+  uint32_t old = f->position;
+  uint32_t to = old + by > f->length ? f->length : old + by;
+  f->position = to;
+  return to - old;
+}
+
+__attribute__ ((pure))
+uint32_t file_size(struct file *f) {
+  return f->length;
+}
\ No newline at end of file
diff --git a/src/user/knob/format.c b/src/user/knob/format.c
new file mode 100644
index 0000000..f55e857
--- /dev/null
+++ b/src/user/knob/format.c
@@ -0,0 +1,13 @@
+#include <stdbool.h>
+#include <stdint.h>
+
+bool try_sntoi(const char *s, uint32_t n, uint32_t *out) {
+  uint32_t calc = 0;
+  for (uint32_t i = 0; i < n; ++i) {
+    if ((s[i] < '0') || (s[i] > '9'))
+      return false;
+    calc = calc * 10 + s[i] - '0';
+  }
+  *out = calc;
+  return true;
+}
\ No newline at end of file
diff --git a/src/user/knob/heap.c b/src/user/knob/heap.c
new file mode 100644
index 0000000..ec21129
--- /dev/null
+++ b/src/user/knob/heap.c
@@ -0,0 +1,112 @@
+#include <pland/syscall.h>
+#include <stdbool.h>
+#include <stdint.h>
+
+//structure appears at the start of each block
+struct block_header {
+  struct block_header *next;
+  struct block_header *prev;
+
+  //does not include header
+  uint32_t length;
+  bool allocated;
+};
+
+static struct block_header *first_block = 0;
+
+static void add_header(struct block_header *bh) {
+  bh->next = first_block;
+  bh->prev = 0;
+  if (first_block)
+    first_block->prev = bh;
+  first_block = bh;
+}
+
+__attribute__ ((malloc))
+void *get_block(uint32_t bytes) {
+  struct block_header *header = 0;
+
+  for (struct block_header *ptr = first_block; ptr; ptr = ptr->next) {
+    if (ptr->allocated)
+      continue;
+    if (ptr->length == bytes) {
+      header = ptr;
+      break;
+    }
+    if (ptr->length > bytes + sizeof(struct block_header)) {
+      struct block_header *bh = (void *)ptr + sizeof(struct block_header) + bytes;
+
+      bh->length = ptr->length - sizeof(struct block_header) - bytes;
+      bh->allocated = false;
+      add_header(bh);
+
+      ptr->length = bytes;
+      header = ptr;
+      break;
+    }
+  }
+
+  if (!header) {
+    uint32_t size_with_header = bytes + sizeof(struct block_header);
+    if (!(size_with_header % 4096)) {
+      header = _allocate_ram(size_with_header / 4096);
+      if (!header)
+        return 0;
+      header->length = bytes;
+      add_header(header);
+    }
+    else {
+      uint32_t pages = (bytes + sizeof(struct block_header) * 2) / 4096 + 1;
+      header = _allocate_ram(pages);
+      if (!header)
+        return 0;
+      header->length = bytes;
+      add_header(header);
+
+      struct block_header *bh = (void *)header + sizeof(struct block_header) + bytes;
+      bh->length = pages * 4096 - bytes - 2 * sizeof(struct block_header);
+      bh->allocated = false;
+      add_header(bh);
+    }
+  }
+
+  header->allocated = true;
+  return (void *)header + sizeof(struct block_header);
+}
+
+static void remove_header(struct block_header *bh) {
+  if (bh == first_block)
+    first_block = bh->next;
+  if (bh->prev)
+    bh->prev->next = bh->next;
+  if (bh->next)
+    bh->next->prev = bh->prev;
+}
+
+void free_block(void *block) {
+  struct block_header *header = block - sizeof(struct block_header);
+
+  header->allocated = false;
+
+  void *after = block + header->length;
+  for (struct block_header *ptr = first_block; ptr; ptr = ptr->next) {
+    if (ptr == after) {
+      if (!ptr->allocated) {
+        header->length += ptr->length + sizeof(struct block_header);
+        remove_header(ptr);
+      }
+      break;
+    }
+  }
+
+  //we traverse the linked list twice. it would probably be more efficient
+  //to do both finding the after and finding the before in the same loop.
+  for (struct block_header *ptr = first_block; ptr; ptr = ptr->next)
+    if ((void *)ptr + sizeof(struct block_header) + ptr->length == header) {
+      if (!ptr->allocated) {
+        ptr->length += sizeof(struct block_header) + header->length;
+        remove_header(header);
+      }
+      break;
+    }
+}
\ No newline at end of file
diff --git a/src/user/knob/quit.c b/src/user/knob/quit.c
new file mode 100644
index 0000000..a2ef5aa
--- /dev/null
+++ b/src/user/knob/quit.c
@@ -0,0 +1,29 @@
+#include <pland/syscall.h>
+#include <knob/heap.h>
+
+struct quit_list_node {
+  struct quit_list_node *prev;
+  void (*f)();
+};
+
+static struct quit_list_node head = {
+  .f = &_exit_task
+};
+
+static struct quit_list_node *last = &head;
+
+void on_quit(void (*run_f)()) {
+  struct quit_list_node *new = get_block(sizeof(struct quit_list_node));
+  new->prev = last;
+  new->f = run_f;
+  last = new;
+}
+
+__attribute__ ((noreturn))
+void quit() {
+  struct quit_list_node *node = last;
+  while (1) {
+    node->f();
+    node = node->prev;
+  }
+}
\ No newline at end of file
diff --git a/src/user/knob/user.c b/src/user/knob/user.c
new file mode 100644
index 0000000..fb39851
--- /dev/null
+++ b/src/user/knob/user.c
@@ -0,0 +1,134 @@
+#include <pland/syscall.h>
+#include <stdint.h>
+#include <stdbool.h>
+
+static const uint8_t caps_and_shift[] = {
+  0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07,
+  0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f,
+  0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16, 0x17,
+  0x18, 0x19, 0x1a, 0x1b, 0x1c, 0x1d, 0x1e, 0x1f,
+  0x20, 0x21, 0x22, 0x23, 0x24, 0x25, 0x26, 0x22,
+  0x28, 0x29, 0x2a, 0x2b, 0x3c, 0x5f, 0x3e, 0x3f,
+  0x29, 0x21, 0x40, 0x23, 0x24, 0x25, 0x5e, 0x26,
+  0x2a, 0x28, 0x3a, 0x3a, 0x3c, 0x2d, 0x3e, 0x3f,
+
+  0x40, 0x61, 0x62, 0x63, 0x64, 0x65, 0x66, 0x67,
+  0x68, 0x69, 0x6a, 0x6b, 0x6c, 0x6d, 0x6e, 0x6f,
+  0x70, 0x71, 0x72, 0x73, 0x74, 0x75, 0x76, 0x77,
+  0x78, 0x79, 0x7a, 0x57, 0x7c, 0x7d, 0x5e, 0x5f,
+  0x7e, 0x61, 0x62, 0x63, 0x64, 0x65, 0x66, 0x67,
+  0x68, 0x69, 0x6a, 0x6b, 0x6c, 0x6d, 0x6e, 0x6f,
+  0x70, 0x71, 0x72, 0x73, 0x74, 0x75, 0x76, 0x77,
+  0x78, 0x79, 0x7a, 0x7b, 0x7c, 0x7d, 0x7e, 0x00
+
+  //TODO: higher
+};
+
+static const uint8_t caps_no_shift[] = {
+  0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07,
+  0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f,
+  0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16, 0x17,
+  0x18, 0x19, 0x1a, 0x1b, 0x1c, 0x1d, 0x1e, 0x1f,
+  0x20, 0x21, 0x22, 0x23, 0x24, 0x25, 0x26, 0x27,
+  0x28, 0x29, 0x2a, 0x2b, 0x2c, 0x2d, 0x2e, 0x2f,
+  0x30, 0x31, 0x32, 0x33, 0x34, 0x35, 0x36, 0x37,
+  0x38, 0x39, 0x3a, 0x3b, 0x3c, 0x3d, 0x3e, 0x3f,
+
+  0x40, 0x41, 0x42, 0x43, 0x44, 0x45, 0x46, 0x47,
+  0x48, 0x49, 0x4a, 0x4b, 0x4c, 0x4d, 0x4e, 0x4f,
+  0x50, 0x51, 0x52, 0x53, 0x54, 0x55, 0x56, 0x57,
+  0x58, 0x59, 0x5a, 0x5b, 0x5c, 0x5d, 0x5e, 0x5f,
+  0x60, 0x41, 0x42, 0x43, 0x44, 0x45, 0x46, 0x47,
+  0x48, 0x49, 0x4a, 0x4b, 0x4c, 0x4d, 0x4e, 0x4f,
+  0x50, 0x51, 0x52, 0x53, 0x54, 0x55, 0x56, 0x57,
+  0x58, 0x59, 0x5a, 0x7b, 0x7c, 0x7d, 0x7e, 0x00
+
+  //TODO: higher
+};
+
+static const uint8_t shifted[] = {
+  0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07,
+  0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f,
+  0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16, 0x17,
+  0x18, 0x19, 0x1a, 0x1b, 0x1c, 0x1d, 0x1e, 0x1f,
+  0x20, 0x21, 0x22, 0x23, 0x24, 0x25, 0x26, 0x22,
+  0x28, 0x29, 0x2a, 0x2b, 0x3c, 0x5f, 0x3e, 0x3f,
+  0x29, 0x21, 0x40, 0x23, 0x24, 0x25, 0x5e, 0x26,
+  0x2a, 0x28, 0x3a, 0x3a, 0x3c, 0x2d, 0x3e, 0x3f,
+
+  0x40, 0x61, 0x62, 0x63, 0x64, 0x65, 0x66, 0x67,
+  0x68, 0x69, 0x6a, 0x6b, 0x6c, 0x6d, 0x6e, 0x6f,
+  0x70, 0x71, 0x72, 0x73, 0x74, 0x75, 0x76, 0x77,
+  0x78, 0x79, 0x7a, 0x57, 0x7c, 0x7d, 0x5e, 0x5f,
+  0x7e, 0x41, 0x42, 0x43, 0x44, 0x45, 0x46, 0x47,
+  0x48, 0x49, 0x4a, 0x4b, 0x4c, 0x4d, 0x4e, 0x4f,
+  0x50, 0x51, 0x52, 0x53, 0x54, 0x55, 0x56, 0x57,
+  0x58, 0x59, 0x5a, 0x7b, 0x7c, 0x7d, 0x7e, 0x00
+
+  //TODO: higher
+};
+
+static char get_key_char() {
+  _key_code_t key;
+  while (!(key = _get_key()))
+    _yield_task();
+  return (char)(
+    (key & (_KEY_ALT | _KEY_CTRL | _KEY_META))
+    ? 0
+    : (key & _KEY_CAPS)
+      ? (key & _KEY_SHIFT)
+        ? caps_and_shift[key & 0xff]
+        : caps_no_shift[key & 0xff]
+      : (key & _KEY_SHIFT)
+        ? shifted[key & 0xff]
+        : (key & 0x80)
+          ? 0
+          : (key & 0x7f)
+  );
+}
+
+void tell_user_sz(const char *sz) {
+  _log_string(sz);
+}
+
+void tell_user_n(uint32_t n) {
+  char buf[11];
+  char *buf_ptr = buf;
+  bool zero_yet = false;
+  for (uint32_t d = 1000000000U; d; d /= 10) {
+    uint8_t v = (n / d ) % 10;
+    if (v || zero_yet) {
+      zero_yet = true;
+      *buf_ptr++ = v | '0';
+    }
+  }
+  if (buf_ptr == buf)
+    *buf_ptr++ = '0';
+  *buf_ptr = '\0';
+  tell_user_sz(buf);
+}
+
+//return value and max_length don't include null terminator
+uint32_t ask_user_line_sz(char *sz, uint32_t max_length) {
+  char log_buf[2];
+  log_buf[1] = '\0';
+
+  uint32_t i;
+  for (i = 0; i != max_length; ++i) {
+    char key = get_key_char();
+    if (key) {
+      log_buf[0] = key;
+      _log_string(log_buf);
+
+      if (key == '\b')
+        i -= i ? 2 : 1;
+      else if (key == '\n')
+        break;
+      else
+        sz[i] = key;
+    }
+  }
+
+  sz[i] = '\0';
+  return i;
+}
\ No newline at end of file
diff --git a/src/user/libcanyo/file.c b/src/user/libcanyo/file.c
deleted file mode 100644
index d314887..0000000
--- a/src/user/libcanyo/file.c
+++ /dev/null
@@ -1,15 +0,0 @@
-#include <stdint.h>
-#include <pland.h>
-
-//max_length and return value include null-terminator
-uint32_t read_line(fs_handle handle, uint32_t max_length, void *buffer) {
-  int index = 0;
-
-  while (++index < max_length) {
-    if (!fs_read(handle, 1, buffer + index - 1) || (*(uint8_t *)(buffer + index - 1) == '\n'))
-      break;
-  }
-
-  *(uint8_t *)(buffer + index - 1) = '\0';
-  return index;
-}
\ No newline at end of file