From bfb74dd57aa0943934647bf56ea5ce7eb927136c Mon Sep 17 00:00:00 2001
From: Freywar Ulvnaudgari <freywar.ulvnaudgari@neuroeventlabs.com>
Date: Fri, 17 Jul 2026 20:30:35 +0300
Subject: [PATCH] Separate log and output streams

---
 src/kernel/fat16.c               |  3 +-
 src/kernel/kernel.c              | 10 ++++---
 src/kernel/process.c             |  9 +++---
 src/lib/util.h                   |  4 +++
 src/user/app/cat/cat.c           |  9 ++----
 src/user/app/cp/cp.c             | 14 ++++-----
 src/user/app/echo/echo.c         |  8 +++---
 src/user/app/ls/ls.c             | 22 +++++++-------
 src/user/app/mkdir/mkdir.c       | 15 ++++------
 src/user/app/rm/rm.c             | 15 ++++------
 src/user/app/shell/shell.c       | 49 ++++++++++++++++++--------------
 src/user/app/terminal/terminal.c | 33 ++++++++++-----------
 src/user/app/wc/wc.c             |  9 ++----
 src/user/syscall.h               |  7 +++++
 14 files changed, 101 insertions(+), 106 deletions(-)

diff --git a/src/kernel/fat16.c b/src/kernel/fat16.c
index 1b14c54..c703cb7 100644
--- a/src/kernel/fat16.c
+++ b/src/kernel/fat16.c
@@ -713,9 +713,8 @@ static uint64_t directory_stream_read(stream_t *self, uint64_t max, char *to) {
     return 0;
   }
   uint64_t length = string_length(node->name);
-  uint64_t to_read = length + 1 > max ? max : length + 1;
+  uint64_t to_read = length > max ? max : length;
   memory_copy(node->name, to_read, to);
-  to[to_read - 1] = '\0';
   return to_read;
 }
 
diff --git a/src/kernel/kernel.c b/src/kernel/kernel.c
index fcd48fb..ac90532 100644
--- a/src/kernel/kernel.c
+++ b/src/kernel/kernel.c
@@ -58,8 +58,10 @@ void kernel_main() {
   kernel->kernel_stack = kernel->kernel_rsp = (uint8_t *)memory_allocate(PAGE_SIZE) + PAGE_SIZE;
   kernel->user_stack = kernel->user_rsp = (uint8_t *)memory_allocate(PAGE_SIZE) + PAGE_SIZE;
   kernel->cwd = memory_allocate(sizeof(path_t));
-  kernel->fds[kernel->free_fd++] = keyboard_init();
-  kernel->fds[kernel->free_fd++] = vga_init();
+  kernel->fds[STDIN] = keyboard_init();
+  kernel->fds[STDOUT] = vga_init();
+  kernel->fds[STDERR] = kernel->fds[STDOUT];
+  kernel->free_fd = STDERR + 1;
   kernel->code = EXIT_CODE_OK;
 
   current_process = kernel;
@@ -79,10 +81,10 @@ void kernel_main() {
   fs_read(shell_node, 0, shell_node->size, shell_code);
   fs_close(shell_node);
 
-  process_t *terminal = process_create(kernel, terminal_code, terminal_node->size, 0, 1);
+  process_t *terminal = process_create(kernel, terminal_code, terminal_node->size, STDIN, STDOUT);
   memory_free(terminal_code);
 
-  process_t *shell = process_create(kernel, shell_code, shell_node->size, 0, 1);
+  process_t *shell = process_create(kernel, shell_code, shell_node->size, STDIN, STDOUT);
   memory_free(shell_code);
 
   uint64_t *terminal_stack = (uint64_t *)terminal->user_stack;
diff --git a/src/kernel/process.c b/src/kernel/process.c
index f5cec1c..b37d2b0 100644
--- a/src/kernel/process.c
+++ b/src/kernel/process.c
@@ -75,9 +75,10 @@ process_t *process_create(const process_t *parent, const uint8_t *code, uint64_t
   proc->pid = free_pid++;
   proc->state = PROCESS_RUNNING;
   proc->cwd = path_open_again(parent->cwd);
-  proc->fds[0] = parent->fds[stdin];
-  proc->fds[1] = parent->fds[stdout];
-  proc->free_fd = 2;
+  proc->fds[STDIN] = parent->fds[stdin];
+  proc->fds[STDOUT] = parent->fds[stdout];
+  proc->fds[STDERR] = parent->fds[STDERR];
+  proc->free_fd = STDERR + 1;
   proc->code = EXIT_CODE_OK;
 
   return proc;
@@ -129,7 +130,7 @@ void process_next() {
 }
 
 void process_destroy(process_t *proc) {
-  for (uint64_t i = 2; i < MAX_FDS; i++) {
+  for (uint64_t i = STDERR + 1; i < MAX_FDS; i++) {
     if (proc->fds[i]) {
       proc->fds[i]->close(proc->fds[i]);
       proc->fds[i] = NUL;
diff --git a/src/lib/util.h b/src/lib/util.h
index 9cffaf5..cfa4afb 100644
--- a/src/lib/util.h
+++ b/src/lib/util.h
@@ -4,6 +4,10 @@
 
 #define NUL 0 // TODO Fix VSCode thinking `NULL` conflicts with some other definition.
 
+#define STDIN 0
+#define STDOUT 1
+#define STDERR 2
+
 typedef uint64_t exit_code_t;
 
 #define EXIT_CODE_OK 0
diff --git a/src/user/app/cat/cat.c b/src/user/app/cat/cat.c
index 407d848..b7820be 100644
--- a/src/user/app/cat/cat.c
+++ b/src/user/app/cat/cat.c
@@ -4,18 +4,15 @@
 
 #define BLOCK_SIZE 65536
 
-#define PRINT_S(s) write(1, s, sizeof(s) - 1);
-#define PRINT_D(s) write(1, s, string_length(s));
-
 exit_code_t pass(uint64_t fd) {
   static char buffer[BLOCK_SIZE];
   uint64_t bytes;
   while ((bytes = read(fd, BLOCK_SIZE, buffer))) {
     if (bytes == (uint64_t)-1) {
-      PRINT_S("cat: could not read file\n");
+      ERR_S("cat: could not read file\n");
       return EXIT_CODE_GENERAL_FAILURE;
     }
-    write(1, buffer, bytes);
+    write(STDOUT, buffer, bytes);
   }
 
   return EXIT_CODE_OK;
@@ -25,7 +22,7 @@ exit_code_t cat(const char *path) {
   uint64_t fd = open(path, OPEN_FILE);
 
   if (fd == (uint64_t)-1) {
-    PRINT_S("cat: path does not exist\n");
+    ERR_S("cat: path does not exist\n");
     return EXIT_CODE_GENERAL_FAILURE;
   }
 
diff --git a/src/user/app/cp/cp.c b/src/user/app/cp/cp.c
index 1258553..005ba61 100644
--- a/src/user/app/cp/cp.c
+++ b/src/user/app/cp/cp.c
@@ -4,29 +4,27 @@
 
 #define BLOCK_SIZE 65536
 
-#define PRINT_S(s) write(1, s, sizeof(s) - 1);
-#define PRINT_D(s) write(1, s, string_length(s));
-
 exit_code_t main(uint64_t argc, const char **argv) {
   if (argc != 3) {
-    PRINT_S("cp: requires source and target");
+    ERR_S("cp: requires source and target\n");
     return EXIT_CODE_GENERAL_FAILURE;
   }
 
   uint64_t source = open(argv[1], OPEN_FILE);
   if (source == (uint64_t)-1) {
-    PRINT_S("cp: source does not exist\n");
+    ERR_S("cp: source does not exist\n");
     return EXIT_CODE_GENERAL_FAILURE;
   }
 
   uint64_t target = open(argv[2], OPEN_FILE | OPEN_CREATE);
   if (target == (uint64_t)-1) {
-    PRINT_S("cp: target path does not exist\n");
+    ERR_S("cp: target path does not exist\n");
     close(source);
     return EXIT_CODE_GENERAL_FAILURE;
   }
 
   if (truncate(target, 0) == (uint64_t)-1) {
+    ERR_S("cp: could not write file\n");
     close(source);
     close(target);
     return EXIT_CODE_GENERAL_FAILURE;
@@ -36,13 +34,13 @@ exit_code_t main(uint64_t argc, const char **argv) {
   uint64_t bytes;
   while ((bytes = read(source, BLOCK_SIZE, buffer))) {
     if (bytes == (uint64_t)-1) {
-      PRINT_S("cp: could not read file\n");
+      ERR_S("cp: could not read file\n");
       close(source);
       close(target);
       return EXIT_CODE_GENERAL_FAILURE;
     }
     if (write(target, buffer, bytes) == (uint64_t)-1) {
-      PRINT_S("cp: could not write file\n");
+      ERR_S("cp: could not write file\n");
       close(source);
       close(target);
       return EXIT_CODE_GENERAL_FAILURE;
diff --git a/src/user/app/echo/echo.c b/src/user/app/echo/echo.c
index 8e06eb8..f5fadbb 100644
--- a/src/user/app/echo/echo.c
+++ b/src/user/app/echo/echo.c
@@ -1,14 +1,14 @@
-#include "src/lib/string.h"
 #include "src/lib/util.h"
 #include "src/user/syscall.h"
 
 exit_code_t main(uint64_t argc, const char **argv) {
   for (uint64_t i = 1; i < argc; i++) {
     if (i > 1) {
-      write(1, " ", 1);
+      OUT_S(" ");
     }
-    write(1, argv[i], string_length(argv[i]));
+    OUT_D(argv[i]);
   }
-  write(1, "\n", 1);
+  OUT_S("\n");
+
   return EXIT_CODE_OK;
 }
diff --git a/src/user/app/ls/ls.c b/src/user/app/ls/ls.c
index 5308a52..d434753 100644
--- a/src/user/app/ls/ls.c
+++ b/src/user/app/ls/ls.c
@@ -1,29 +1,27 @@
-#include "src/lib/string.h"
 #include "src/lib/syscall.h"
 #include "src/lib/util.h"
 #include "src/user/syscall.h"
 
-#define PRINT_S(s) write(1, s, sizeof(s) - 1);
-#define PRINT_D(s) write(1, s, string_length(s));
+#define BLOCK_SIZE 256
 
 exit_code_t ls(const char *path) {
   uint64_t fd = open(path, OPEN_DIRECTORY);
 
   if (fd == (uint64_t)-1) {
-    PRINT_S("ls: path does not exist\n");
+    ERR_S("ls: path does not exist\n");
     return EXIT_CODE_GENERAL_FAILURE;
   }
 
-  char buffer[100];
+  char buffer[BLOCK_SIZE];
   uint64_t bytes;
-  while ((bytes = read(fd, 100, buffer))) {
+  while ((bytes = read(fd, BLOCK_SIZE, buffer))) {
     if (bytes == (uint64_t)-1) {
-      PRINT_S("ls: could not read directory\n");
+      ERR_S("ls: could not read directory\n");
       close(fd);
       return EXIT_CODE_GENERAL_FAILURE;
     }
-    write(1, buffer, bytes - 1);
-    PRINT_S("\n");
+    write(STDOUT, buffer, bytes);
+    OUT_S("\n");
   }
 
   close(fd);
@@ -39,9 +37,9 @@ exit_code_t main(uint64_t argc, const char **argv) {
   exit_code_t code = EXIT_CODE_OK;
   for (uint64_t i = 1; i < argc; i++) {
     if (argc > 2) {
-      PRINT_S("\n");
-      PRINT_D(argv[i]);
-      PRINT_S(":\n");
+      OUT_S("\n");
+      OUT_D(argv[i]);
+      OUT_S(":\n");
     }
     exit_code_t c = ls(argv[i]);
     if (c != EXIT_CODE_OK) {
diff --git a/src/user/app/mkdir/mkdir.c b/src/user/app/mkdir/mkdir.c
index eb552d2..aa07a26 100644
--- a/src/user/app/mkdir/mkdir.c
+++ b/src/user/app/mkdir/mkdir.c
@@ -1,28 +1,23 @@
 #include "src/lib/syscall.h"
 #include "src/lib/util.h"
 #include "src/user/syscall.h"
-#include <stdint.h>
-
-#define BLOCK_SIZE 65536
-
-#define PRINT_S(s) write(1, s, sizeof(s) - 1);
-#define PRINT_D(s) write(1, s, string_length(s));
 
 exit_code_t main(uint64_t argc, const char **argv) {
   if (argc < 2) {
-    PRINT_S("mkdir: requires target(s)\n");
+    ERR_S("mkdir: requires target(s)\n");
     return EXIT_CODE_GENERAL_FAILURE;
   }
 
+  exit_code_t code = EXIT_CODE_OK;
   for (uint64_t i = 1; i < argc; i++) {
     uint64_t fd = open(argv[i], OPEN_DIRECTORY | OPEN_CREATE | OPEN_EXCLUSIVE);
     if (fd == (uint64_t)-1) {
-      PRINT_S("mkdir: could not create directory\n");
-      return EXIT_CODE_GENERAL_FAILURE;
+      ERR_S("mkdir: could not create directory\n");
+      code = EXIT_CODE_GENERAL_FAILURE;
     } else {
       close(fd);
     }
   }
 
-  return EXIT_CODE_OK;
+  return code;
 }
diff --git a/src/user/app/rm/rm.c b/src/user/app/rm/rm.c
index f954f33..b557e6f 100644
--- a/src/user/app/rm/rm.c
+++ b/src/user/app/rm/rm.c
@@ -2,23 +2,18 @@
 #include "src/lib/util.h"
 #include "src/user/syscall.h"
 
-#define BLOCK_SIZE 65536
-
-#define PRINT_S(s) write(1, s, sizeof(s) - 1);
-#define PRINT_D(s) write(1, s, string_length(s));
-
 exit_code_t main(uint64_t argc, const char **argv) {
   if (argc < 2) {
-    PRINT_S("rm: requires one or more arguments\n");
+    ERR_S("rm: requires one or more arguments\n");
     return EXIT_CODE_GENERAL_FAILURE;
   }
 
   uint64_t code = EXIT_CODE_OK;
   for (uint64_t i = 1; i < argc; i++) {
-    exit_code_t c = remove(argv[i]);
-    if (c != EXIT_CODE_OK) {
-      PRINT_S("rm: coult not remove file\n");
-      code = c;
+    uint64_t removed = remove(argv[i]);
+    if (removed == (uint64_t)-1) {
+      ERR_S("rm: could not remove file\n");
+      code = EXIT_CODE_GENERAL_FAILURE;
     }
   }
 
diff --git a/src/user/app/shell/shell.c b/src/user/app/shell/shell.c
index 693cbd4..9553799 100644
--- a/src/user/app/shell/shell.c
+++ b/src/user/app/shell/shell.c
@@ -3,15 +3,15 @@
 #include "src/lib/util.h"
 #include "src/user/syscall.h"
 
-static void help(uint8_t argc, char **argv, uint64_t stdin, uint64_t stdout);
-static void cd(uint8_t argc, char **argv, uint64_t stdin, uint64_t stdout);
+static exit_code_t help(uint8_t argc, char **argv, uint64_t stdin, uint64_t stdout);
+static exit_code_t cd(uint8_t argc, char **argv, uint64_t stdin, uint64_t stdout);
 
 #define PATH "/bin/"
 
-#define PRINT_S(o, s) write(o, s, sizeof(s) - 1);
-#define PRINT_D(o, s) write(o, s, string_length(s));
+#define WRITE_S(o, s) write(o, s, sizeof(s) - 1);
+#define WRITE_D(o, s) write(o, s, string_length(s));
 
-typedef void (*app_t)(uint8_t argc, char **argv, uint64_t stdin, uint64_t stdout);
+typedef exit_code_t (*app_t)(uint8_t argc, char **argv, uint64_t stdin, uint64_t stdout);
 
 typedef struct {
   const char *name;
@@ -23,28 +23,33 @@ static app_entry_t builtins[] = {
     {"cd", cd},
 };
 
-static void help(uint8_t argc, __attribute__((unused)) char **argv, __attribute__((unused)) uint64_t stdin, uint64_t stdout) {
+static exit_code_t help(uint8_t argc, __attribute__((unused)) char **argv, __attribute__((unused)) uint64_t stdin, uint64_t stdout) {
   if (argc > 1) {
-    PRINT_S(stdout, "help: expects no arguments\n");
-    return;
+    ERR_S("help: expects no arguments\n");
+    return EXIT_CODE_GENERAL_FAILURE;
   }
 
-  PRINT_S(stdout, "Available commands:\n");
+  WRITE_S(stdout, "Available commands:\n");
   for (uint64_t i = 0; i < sizeof(builtins) / sizeof(app_entry_t); i++) {
-    PRINT_D(stdout, builtins[i].name);
-    PRINT_S(stdout, "\n");
+    WRITE_D(stdout, builtins[i].name);
+    WRITE_S(stdout, "\n");
   }
+
+  return EXIT_CODE_OK;
 }
 
-static void cd(uint8_t argc, char **argv, __attribute__((unused)) uint64_t stdin, uint64_t stdout) {
+static exit_code_t cd(uint8_t argc, char **argv, __attribute__((unused)) uint64_t stdin, __attribute__((unused)) uint64_t stdout) {
   if (argc != 2) {
-    PRINT_S(stdout, "cd: requires a single path\n");
-    return;
+    ERR_S("cd: requires a single path\n");
+    return EXIT_CODE_GENERAL_FAILURE;
   }
 
   if (chdir(argv[1]) == (uint64_t)-1) {
-    PRINT_S(stdout, "cd: path does not exist\n");
+    ERR_S("cd: path does not exist\n");
+    return EXIT_CODE_GENERAL_FAILURE;
   }
+
+  return EXIT_CODE_OK;
 }
 
 static void print_prompt() {
@@ -53,9 +58,9 @@ static void print_prompt() {
   char *components[16];
   uint8_t cl = string_split(path, '/', 16, components);
 
-  PRINT_S(1, "[")
-  PRINT_D(1, pl == 1 ? "/" : components[cl - 1]);
-  PRINT_S(1, "]$ ");
+  OUT_S("[")
+  OUT_D(pl == 1 ? "/" : components[cl - 1]);
+  OUT_S("]$ ");
 }
 
 static void free_fds(uint64_t *fds, uint8_t fds_count) {
@@ -69,7 +74,7 @@ static void kill_pids(__attribute__((unused)) uint64_t *pids, __attribute__((unu
 }
 
 static void execute(char *command) {
-  PRINT_S(1, "\n");
+  OUT_S("\n");
 
   if (string_equal(command, "^C")) {
     print_prompt();
@@ -155,8 +160,8 @@ static void execute(char *command) {
   print_prompt();
 }
 
-uint64_t main() {
-  PRINT_D(1, "Welcome to FreywarOS v" VERSION "!\n\n");
+exit_code_t main() {
+  ERR_S("Welcome to FreywarOS v" VERSION "!\n\n");
 
   print_prompt();
 
@@ -178,5 +183,5 @@ uint64_t main() {
     }
   }
 
-  return 0;
+  return EXIT_CODE_OK;
 }
diff --git a/src/user/app/terminal/terminal.c b/src/user/app/terminal/terminal.c
index b4d101b..6d841f7 100644
--- a/src/user/app/terminal/terminal.c
+++ b/src/user/app/terminal/terminal.c
@@ -2,9 +2,6 @@
 #include "src/lib/util.h"
 #include "src/user/syscall.h"
 
-#define PRINT_S(s) write(1, s, sizeof(s) - 1);
-#define PRINT_D(s) write(1, s, string_length(s));
-
 #define PROMPT_LENGTH 255
 
 static const char bs[PROMPT_LENGTH + 1];
@@ -19,7 +16,7 @@ static void on_home_pressed() {
     return;
   }
 
-  write(1, bs, prompt_offset);
+  write(STDOUT, bs, prompt_offset);
   prompt_offset = 0;
 }
 
@@ -28,7 +25,7 @@ static void on_left_pressed() {
     return;
   }
 
-  write(1, bs, 1);
+  write(STDOUT, bs, 1);
   prompt_offset--;
 }
 
@@ -37,7 +34,7 @@ static void on_right_pressed() {
     return;
   }
 
-  write(1, prompt + prompt_offset, 1);
+  write(STDOUT, prompt + prompt_offset, 1);
   prompt_offset++;
 }
 
@@ -46,27 +43,27 @@ static void on_end_pressed() {
     return;
   }
 
-  write(1, prompt + prompt_offset, prompt_length - prompt_offset);
+  write(STDOUT, prompt + prompt_offset, prompt_length - prompt_offset);
   prompt_offset = prompt_length;
 }
 
 static void on_enter_pressed() {
   prompt[prompt_length] = '\n';
 
-  write(2, prompt, prompt_length + 1);
+  write(3, prompt, prompt_length + 1);
 
   prompt_length = prompt_offset = 0;
 }
 
 static void on_cancel_pressed() {
-  PRINT_S("^C\n");
-  write(2, "^C\n", 3);
+  OUT_S("^C\n");
+  write(3, "^C\n", 3);
   prompt_length = prompt_offset = 0;
 }
 
 static void on_disconnect_pressed() {
-  PRINT_S("^D\n");
-  write(2, "^D\n", 3);
+  OUT_S("^D\n");
+  write(3, "^D\n", 3);
   exit(EXIT_CODE_OK);
 }
 
@@ -80,9 +77,9 @@ static void on_ctrl_character_pressed(char c) {
 
 static void redraw_from_cursor() {
   uint64_t tail = prompt_length - prompt_offset;
-  write(1, prompt + prompt_offset, tail);
-  write(1, ws, 1);        // erase the character past the end
-  write(1, bs, tail + 1); // move back to cursor position
+  write(STDOUT, prompt + prompt_offset, tail);
+  write(STDOUT, ws, 1);        // erase the character past the end
+  write(STDOUT, bs, tail + 1); // move back to cursor position
 }
 
 static void on_character_pressed(char c) {
@@ -96,7 +93,7 @@ static void on_character_pressed(char c) {
   prompt_length++;
   prompt_offset++;
 
-  write(1, &c, 1); // emit the character itself
+  write(STDOUT, &c, 1); // emit the character itself
   redraw_from_cursor();
 }
 
@@ -110,7 +107,7 @@ static void on_backspace_pressed() {
   prompt_offset--;
   prompt_length--;
 
-  write(1, bs, 1);
+  write(STDOUT, bs, 1);
   redraw_from_cursor();
 }
 
@@ -197,7 +194,7 @@ uint64_t main() {
   memory_set(' ', PROMPT_LENGTH, (char *)ws);
 
   char c;
-  while (read(0, 1, &c)) {
+  while (read(STDIN, 1, &c)) {
     on_char_received(c);
   }
 
diff --git a/src/user/app/wc/wc.c b/src/user/app/wc/wc.c
index f437f81..36f20af 100644
--- a/src/user/app/wc/wc.c
+++ b/src/user/app/wc/wc.c
@@ -5,16 +5,13 @@
 
 #define BLOCK_SIZE 65536
 
-#define PRINT_S(s) write(1, s, sizeof(s) - 1);
-#define PRINT_D(s) write(1, s, string_length(s));
-
 exit_code_t pass(uint64_t fd) {
   static char buffer[BLOCK_SIZE];
   uint64_t bytes;
   uint64_t total = 0;
   while ((bytes = read(fd, BLOCK_SIZE, buffer))) {
     if (bytes == (uint64_t)-1) {
-      PRINT_S("wc: could not read file\n");
+      ERR_S("wc: could not read file\n");
       return EXIT_CODE_GENERAL_FAILURE;
     } else {
       total += bytes;
@@ -22,7 +19,7 @@ exit_code_t pass(uint64_t fd) {
   }
 
   uint64_t l = string_format("%d\n", BLOCK_SIZE, buffer, total);
-  write(1, buffer, l);
+  write(STDOUT, buffer, l);
 
   return EXIT_CODE_OK;
 }
@@ -31,7 +28,7 @@ exit_code_t wc(const char *path) {
   uint64_t fd = open(path, OPEN_FILE);
 
   if (fd == (uint64_t)-1) {
-    PRINT_S("wc: path does not exist\n");
+    OUT_S("wc: path does not exist\n");
     return EXIT_CODE_GENERAL_FAILURE;
   }
 
diff --git a/src/user/syscall.h b/src/user/syscall.h
index b96ea21..842ae18 100644
--- a/src/user/syscall.h
+++ b/src/user/syscall.h
@@ -1,6 +1,13 @@
 #pragma once
 
 #include "src/lib/util.h"
+#include "src/lib/string.h"
+
+#define OUT_S(s) write(STDOUT, s, sizeof(s) - 1);
+#define OUT_D(s) write(STDOUT, s, string_length(s));
+
+#define ERR_S(s) write(STDERR, s, sizeof(s) - 1);
+#define ERR_D(s) write(STDERR, s, string_length(s));
 
 uint64_t read(int64_t fd, uint64_t max, void *to);