Add process state

meson.build

@@ -52,6 +52,7 @@ kernel_sources = files(
   'src/keyboard.c',
   'src/memory.c',
   'src/panic.c',
+  'src/path.c',
   'src/pic.c',
   'src/string.c',
   'src/vga.c',

src/app/cat.c

@@ -1,78 +1,31 @@
 #include "src/app/cat.h"
 #include "src/fs.h"
 #include "src/memory.h"
-#include "src/string.h"
-#include "src/util.h"
-
+#include "src/path.h"
 #include <stdint.h>
 
-static stream_t *stream_in;
-static stream_t *stream_out;
-
-#define WRITE_S(s) stream_out->write(stream_out, s, sizeof(s) - 1);
-#define WRITE_D(s) stream_out->write(stream_out, s, string_length(s));
-
-void cat(stream_t *stdin, stream_t *stdout, uint8_t argc, char **argv) {
-  stream_in = stdin;
-  stream_out = stdout;
-
+void cat(process_t *proc, uint8_t argc, char **argv) {
   if (argc != 2) {
     WRITE_S("cat: requires a single path\n");
     return;
   }
 
-  char *path_components[16];
-  uint64_t path_length = string_split(argv[1], '/', 16, path_components);
-  if (!string_empty(path_components[0])) {
-    WRITE_S("cat: relative paths not supported\n");
-    return;
-  }
-
-  fs_node_t *root = fs_mount();
-
-  fs_node_t *prev = NUL;
-  fs_node_t *curr = root;
-  uint8_t i = 1;
-  while (i < path_length) {
-    if (string_empty(path_components[i])) {
-      i++;
-      continue;
-    }
-
-    if (!curr->is_dir) {
-      WRITE_S("cat: can not navigate into a file\n");
-      fs_close(curr);
-      return;
-    }
-
-    prev = curr;
-    curr = fs_open_by(curr, path_components[i]);
-    if (prev != root) {
-      fs_close(prev);
-    }
-
-    if (!curr) {
+  path_t *path = path_open(proc->root, proc->cwd, argv[1]);
+  if (!path) {
     WRITE_S("cat: invalid path\n");
     return;
   }
-    i++;
-  }
 
+  fs_node_t *curr = path->depth ? path->stack[path->depth - 1] : proc->root;
   if (curr->is_dir) {
     WRITE_S("cat: can not print a directory\n");
-    if (curr != root) {
-      fs_close(curr);
-    }
+    path_close(path);
     return;
   }
 
   char *content = memory_allocate(curr->size + 1);
   fs_read(curr, 0, curr->size, content);
-  stream_out->write(stream_out, content, curr->size);
+  proc->stdout->write(proc->stdout, content, curr->size);
   memory_free(content);
-  fs_close(curr);
-
-  fs_unmount(root);
-
-  stream_in = stream_out = NUL;
+  path_close(path);
 }

src/app/cat.h

@@ -1,5 +1,5 @@
 #pragma once
 
-#include "src/stream.h"
+#include "src/process.h"
 
-void cat(stream_t *stdin, stream_t *stdout, uint8_t argc, char **argv);
+void cat(process_t *proc, uint8_t argc, char **argv);

src/app/ls.c

@@ -1,65 +1,24 @@
 #include "src/app/ls.h"
 #include "src/fs.h"
-#include "src/string.h"
-#include "src/util.h"
-
+#include "src/path.h"
 #include <stdint.h>
 
-static stream_t *stream_in;
-static stream_t *stream_out;
-
-#define WRITE_S(s) stream_out->write(stream_out, s, sizeof(s) - 1);
-#define WRITE_D(s) stream_out->write(stream_out, s, string_length(s));
-
-void ls(stream_t *stdin, stream_t *stdout, uint8_t argc, char **argv) {
-  stream_in = stdin;
-  stream_out = stdout;
-
-  if (argc != 2) {
+void ls(process_t *proc, uint8_t argc, char **argv) {
+  if (argc > 2) {
     WRITE_S("ls: requires a single path\n");
     return;
   }
 
-  char *path_components[16];
-  uint64_t path_length = string_split(argv[1], '/', 16, path_components);
-  if (!string_empty(path_components[0])) {
-    WRITE_S("ls: relative paths not supported\n");
-    return;
-  }
-
-  fs_node_t *root = fs_mount();
-
-  fs_node_t *prev = NUL;
-  fs_node_t *curr = root;
-  uint8_t i = 1;
-  while (i < path_length) {
-    if (string_empty(path_components[i])) {
-      i++;
-      continue;
-    }
-
-    if (!curr->is_dir) {
-      WRITE_S("ls: can not navigate into a file\n");
-      fs_close(curr);
-      return;
-    }
-
-    prev = curr;
-    curr = fs_open_by(curr, path_components[i]);
-    if (prev != root) {
-      fs_close(prev);
-    }
-
-    if (!curr) {
+  path_t *path = path_open(proc->root, proc->cwd, argc == 1 ? "." : argv[1]);
+  if (!path) {
     WRITE_S("ls: invalid path\n");
     return;
   }
-    i++;
-  }
 
+  fs_node_t *curr = path->depth ? path->stack[path->depth - 1] : proc->root;
   if (!curr->is_dir) {
-    WRITE_S("ls: can not list file\n");
-    fs_close(curr);
+    WRITE_S("ls: can not list a file\n");
+    path_close(path);
     return;
   }
 
@@ -71,11 +30,5 @@ void ls(stream_t *stdin, stream_t *stdout, uint8_t argc, char **argv) {
     fs_close(item);
     item = fs_open_at(curr, j++);
   }
-  if (curr != root) {
-    fs_close(curr);
-  }
-
-  fs_unmount(root);
-
-  stream_in = stream_out = NUL;
+  path_close(path);
 }

src/app/ls.h

@@ -1,5 +1,5 @@
 #pragma once
 
-#include "src/stream.h"
+#include "src/process.h"
 
-void ls(stream_t *stdin, stream_t *stdout, uint8_t argc, char **argv);
+void ls(process_t *proc, uint8_t argc, char **argv);

src/app/terminal.c

@@ -3,14 +3,17 @@
 #include "src/app/ls.h"
 #include "src/fs.h"
 #include "src/memory.h"
+#include "src/path.h"
+#include "src/process.h"
 #include "src/string.h"
 #include "src/util.h"
 
 #include <stdint.h>
 
-#define PROMPT_LENGTH 255
+static void help(process_t *proc, uint8_t argc, char **argv);
+static void cd(process_t *proc, uint8_t argc, char **argv);
 
-fs_node_t *root;
+#define PROMPT_LENGTH 255
 
 static const char bs[PROMPT_LENGTH + 1];
 static const char ws[PROMPT_LENGTH + 1];
@@ -19,20 +22,63 @@ static char prompt[PROMPT_LENGTH + 1];
 static uint8_t prompt_length = 0;
 static uint8_t prompt_offset = 0;
 
-static stream_t *stream_in;
-static stream_t *stream_out;
+process_t *proc;
 
 static uint8_t active = 1;
 
-#define WRITE_S(s) stream_out->write(stream_out, s, sizeof(s) - 1);
-#define WRITE_D(s) stream_out->write(stream_out, s, string_length(s));
+typedef struct {
+  const char *name;
+  app_t app;
+} app_entry_t;
+
+static app_entry_t apps[] = {
+    {"help", help},
+    {"cd", cd},
+    {"ls", ls},
+    {"cat", cat},
+};
+
+static void help(process_t *proc, uint8_t argc, __attribute__((unused)) char **argv) {
+  if (argc > 1) {
+    WRITE_S("help: accepts no arguments\n");
+  }
+
+  WRITE_S("Available commands:\n");
+  for (uint64_t i = 0; i < sizeof(apps) / sizeof(app_entry_t); i++) {
+    WRITE_D(apps[i].name);
+    WRITE_S("\n");
+  }
+}
+
+static void cd(process_t *proc, uint8_t argc, char **argv) {
+  if (argc != 2) {
+    WRITE_S("cd: requires a single path\n");
+    return;
+  }
+
+  path_t *new = path_open(proc->root, proc->cwd, argv[1]);
+  if (!new) {
+    WRITE_S("cd: path does not exist\n");
+    return;
+  }
+
+  path_close(proc->cwd);
+  proc->cwd = new;
+}
+
+static void print_prompt() {
+  WRITE_S("[");
+  fs_node_t *curr = proc->cwd->depth ? proc->cwd->stack[proc->cwd->depth - 1] : proc->root;
+  WRITE_D(curr->name);
+  WRITE_S("]$ ");
+}
 
 static void on_home_pressed() {
   if (!prompt_offset) {
     return;
   }
 
-  stream_out->write(stream_out, bs, prompt_offset);
+  proc->stdout->write(proc->stdout, bs, prompt_offset);
   prompt_offset = 0;
 }
 
@@ -41,7 +87,7 @@ static void on_left_pressed() {
     return;
   }
 
-  stream_out->write(stream_out, bs, 1);
+  proc->stdout->write(proc->stdout, bs, 1);
   prompt_offset--;
 }
 
@@ -50,7 +96,7 @@ static void on_right_pressed() {
     return;
   }
 
-  stream_out->write(stream_out, prompt + prompt_offset, 1);
+  proc->stdout->write(proc->stdout, prompt + prompt_offset, 1);
   prompt_offset++;
 }
 
@@ -59,21 +105,10 @@ static void on_end_pressed() {
     return;
   }
 
-  stream_out->write(stream_out, prompt + prompt_offset, prompt_length - prompt_offset);
+  proc->stdout->write(proc->stdout, prompt + prompt_offset, prompt_length - prompt_offset);
   prompt_offset = prompt_length;
 }
 
-static void help(uint8_t argc, __attribute__((unused)) char **argv) {
-  if (argc > 1) {
-    WRITE_S("help: accepts no arguments\n");
-  }
-
-  WRITE_S("Available commands:\n"
-          "help\n"
-          "ls DIR\n"
-          "cat FILE\n")
-}
-
 static void on_enter_pressed() {
   prompt[prompt_length] = '\0';
 
@@ -82,23 +117,24 @@ static void on_enter_pressed() {
 
   WRITE_S("\n");
 
-  if (string_equal(argv[0], "help")) {
-    help(argc, argv);
-  } else if (string_equal(argv[0], "ls")) {
-    ls(stream_in, stream_out, argc, argv);
-  } else if (string_equal(argv[0], "cat")) {
-    cat(stream_in, stream_out, argc, argv);
-  } else {
+  uint8_t i;
+  for (i = 0; i < sizeof(apps) / sizeof(app_entry_t); i++) {
+    if (string_equal(argv[0], apps[i].name)) {
+      apps[i].app(proc, argc, argv);
+      break;
+    }
+  }
+  if (i == sizeof(apps) / sizeof(app_entry_t)) {
     WRITE_S("Unknown command\n");
   }
-  WRITE_S("$ ");
   prompt_length = prompt_offset = 0;
+  print_prompt();
 }
 
 static void on_cancel_pressed() {
   WRITE_S("^C\n");
-  WRITE_S("$ ");
   prompt_length = prompt_offset = 0;
+  print_prompt();
 }
 
 static void on_disconnect_pressed() {
@@ -116,9 +152,9 @@ static void on_ctrl_character_pressed(char c) {
 
 static void redraw_from_cursor() {
   uint64_t tail = prompt_length - prompt_offset;
-  stream_out->write(stream_out, prompt + prompt_offset, tail);
-  stream_out->write(stream_out, ws, 1);        // erase the character past the end
-  stream_out->write(stream_out, bs, tail + 1); // move back to cursor position
+  proc->stdout->write(proc->stdout, prompt + prompt_offset, tail);
+  proc->stdout->write(proc->stdout, ws, 1);        // erase the character past the end
+  proc->stdout->write(proc->stdout, bs, tail + 1); // move back to cursor position
 }
 
 static void on_character_pressed(char c) {
@@ -132,7 +168,7 @@ static void on_character_pressed(char c) {
   prompt_length++;
   prompt_offset++;
 
-  stream_out->write(stream_out, &c, 1); // emit the character itself
+  proc->stdout->write(proc->stdout, &c, 1); // emit the character itself
   redraw_from_cursor();
 }
 
@@ -146,7 +182,7 @@ static void on_backspace_pressed() {
   prompt_offset--;
   prompt_length--;
 
-  stream_out->write(stream_out, bs, 1);
+  proc->stdout->write(proc->stdout, bs, 1);
   redraw_from_cursor();
 }
 
@@ -228,28 +264,24 @@ static void on_char_received(char c) {
   }
 }
 
-void terminal(stream_t *stdin, stream_t *stdout, __attribute__((unused)) uint8_t argc, __attribute__((unused)) char **argv) {
+void terminal(process_t *p, __attribute__((unused)) uint8_t argc, __attribute__((unused)) char **argv) {
   memory_set('\b', PROMPT_LENGTH, (char *)bs);
   memory_set(' ', PROMPT_LENGTH, (char *)ws);
 
-  stream_in = stdin;
-  stream_out = stdout;
-
-  root = fs_mount();
+  proc = p;
 
   char *greeting = string_format("Welcome to FreywarOS v%s!\n\n", VERSION);
   WRITE_D(greeting);
   memory_free(greeting);
 
-  WRITE_S("$ ");
+  print_prompt();
 
   while (active) {
     char c;
-    if (stream_in->read(stream_in, 1, &c)) {
+    if (proc->stdin->read(proc->stdin, 1, &c)) {
       on_char_received(c);
     }
   }
 
-  // fs_unmount(root);
-  stream_in = stream_out = NUL;
+  proc = NUL;
 }

src/app/terminal.h

@@ -1,5 +1,5 @@
 #pragma once
 
-#include "src/stream.h"
+#include "src/process.h"
 
-void terminal(stream_t *stdin, stream_t *stdout, uint8_t argc, char **argv);
+void terminal(process_t *proc, uint8_t argc, char **argv);

src/fat16.c

@@ -1,5 +1,6 @@
 #include "src/fat16.h"
 #include "src/ata.h"
+#include "src/fs.h"
 #include "src/memory.h"
 #include "src/string.h"
 #include "src/util.h"
@@ -86,7 +87,7 @@ fs_node_t *fat16_mount() { // Assuming one partition.
 }
 
 static void ensure_fat() {
-  ASSERT(bpb.sectors_per_fat<256, "ensure_fat: big FAT not implemented")
+  ASSERT(bpb.sectors_per_fat < 256, "ensure_fat: big FAT not implemented")
   if (!fat) {
     fat = memory_allocate(bpb.sectors_per_fat * SECTOR_SIZE);
     ata_read_sectors(FIRST_PARTITION_SECTOR + bpb.reserved_sectors, (uint8_t)bpb.sectors_per_fat, fat);
@@ -193,6 +194,12 @@ fs_node_t *fat16_open_at(const fs_node_t *directory, uint64_t index) {
   return result;
 }
 
+fs_node_t *fat16_open_again(const fs_node_t *source) {
+  fs_node_t *result = memory_allocate(sizeof(fat16_node_t));
+  memory_copy(source, sizeof(fat16_node_t), result);
+  return result;
+}
+
 void fat16_read(const fs_node_t *file, uint64_t offset, uint64_t size, void *to) {
   ASSERT(file->type == FAT16, "fat16_read: file is not FAT16");
   ASSERT(!file->is_dir, "fat16_read: can not read directory");

src/fat16.h

@@ -10,6 +10,8 @@ fs_node_t *fat16_open_by(const fs_node_t *directory, const char *name);
 
 fs_node_t *fat16_open_at(const fs_node_t *directory, uint64_t index);
 
+fs_node_t *fat16_open_again(const fs_node_t *source);
+
 void fat16_read(const fs_node_t *file, uint64_t offset, uint64_t size, void *to);
 
 void fat16_close(fs_node_t *node);

src/fs.c

@@ -13,6 +13,10 @@ fs_node_t *fs_open_at(const fs_node_t *directory, uint64_t index) {
   return fat16_open_at(directory, index);
 }
 
+fs_node_t *fs_open_again(const fs_node_t *source) {
+  return fat16_open_again(source);
+}
+
 void fs_read(const fs_node_t *file, uint64_t offset, uint64_t size, void *to) {
   fat16_read(file, offset, size, to);
 }

src/fs.h

@@ -18,6 +18,8 @@ fs_node_t *fs_open_by(const fs_node_t *directory, const char *name);
 
 fs_node_t *fs_open_at(const fs_node_t *directory, uint64_t index);
 
+fs_node_t *fs_open_again(const fs_node_t *source);
+
 void fs_read(const fs_node_t *file, uint64_t offset, uint64_t size, void *to);
 
 void fs_close(fs_node_t *node);

src/kernel.c

@@ -1,9 +1,11 @@
 #include "src/app/terminal.h"
+#include "src/fs.h"
 #include "src/idt.h"
 #include "src/keyboard.h"
 #include "src/memory.h"
+#include "src/path.h"
 #include "src/pic.h"
-#include "src/stream.h"
+#include "src/process.h"
 #include "src/util.h"
 #include "src/vga.h"
 
@@ -42,10 +44,13 @@ void kernel_main() {
 
   memory_init();
 
-  stream_t *stdin = keyboard_init();
-  stream_t *stdout = vga_init();
+  process_t *proc = memory_allocate(sizeof(process_t));
+  proc->cwd = memory_allocate(sizeof(path_t));
+  proc->root = fs_mount();
+  proc->stdin = keyboard_init();
+  proc->stdout = vga_init();
 
-  terminal(stdin, stdout, 0, NUL);
+  terminal(proc, 0, NUL);
 
   outw(0x604, 0x2000); // TODO: parse ACPI tables for real hardware
   __asm__ volatile("cli; hlt");

src/path.c

@@ -0,0 +1,46 @@
+#include "src/path.h"
+#include "src/fs.h"
+#include "src/memory.h"
+#include "src/string.h"
+#include "src/util.h"
+#include <stdint.h>
+
+path_t *path_open(const fs_node_t *root, const path_t *source, char *path) {
+  path_t *result = memory_allocate(sizeof(path_t));
+
+  char *path_components[PATH_DEPTH];
+  uint8_t path_length = (uint8_t)string_split(path, '/', PATH_DEPTH, path_components);
+  if (!string_empty(path_components[0])) {
+    for (uint8_t i = 0; i < source->depth; i++) {
+      result->stack[result->depth++] = fs_open_again(source->stack[i]);
+    }
+  }
+
+  for (uint8_t i = 0; i < path_length; i++) {
+    if (string_empty(path_components[i]) || string_equal(path_components[i], ".")) {
+      continue;
+    } else if (string_equal(path_components[i], "..")) {
+      if (result->depth) {
+        fs_close(result->stack[--result->depth]);
+      }
+    } else {
+      const fs_node_t *prev = result->depth ? result->stack[result->depth - 1] : root;
+      fs_node_t *next = prev->is_dir ? fs_open_by(prev, path_components[i]) : NUL;
+      if (!next || result->depth >= PATH_DEPTH) {
+        path_close(result);
+        return NUL;
+      } else {
+        result->stack[result->depth++] = next;
+      }
+    }
+  }
+
+  return result;
+}
+
+void path_close(path_t *path) {
+  for (uint64_t i = 0; i < path->depth; i++) {
+    fs_close(path->stack[i]);
+  }
+  memory_free(path);
+}

src/path.h

@@ -0,0 +1,15 @@
+#pragma once
+
+#include "src/fs.h"
+#include <stdint.h>
+
+#define PATH_DEPTH 255
+
+typedef struct {
+  fs_node_t *stack[PATH_DEPTH];
+  uint8_t depth;
+} path_t;
+
+path_t *path_open(const fs_node_t *root, const path_t *source, char *path);
+
+void path_close(path_t *path);

src/process.h

@@ -0,0 +1,18 @@
+#pragma once
+
+#include "src/fs.h"
+#include "src/path.h"
+#include "src/stream.h"
+#include "src/string.h"
+
+typedef struct {
+  path_t *cwd;
+  fs_node_t *root;
+  stream_t *stdin;
+  stream_t *stdout;
+} process_t;
+
+typedef void (*app_t)(process_t *proc, uint8_t argc, char **argv);
+
+#define WRITE_S(s) proc->stdout->write(proc->stdout, s, sizeof(s) - 1);
+#define WRITE_D(s) proc->stdout->write(proc->stdout, s, string_length(s));