Implemented UNIX like streams (STDIN, STDOUT, STDERR) and ported the existing code.

Author: pradosh-arduino

source/drivers/networking/ethernet/RTL/8139.c

@@ -34,8 +34,7 @@ void rtl8139_init(struct rtl8139* nic) {
     // Initialize MAC address
     read_mac_address();
 
-    print("Mac Address: ");
-    printf("%x:%x:%x:%x:%x:%x", nic->mac_address[0], nic->mac_address[1], nic->mac_address[2], nic->mac_address[3], nic->mac_address[4], nic->mac_address[5]);
+    printf("Mac Address : %x:%x:%x:%x:%x:%x", nic->mac_address[0], nic->mac_address[1], nic->mac_address[2], nic->mac_address[3], nic->mac_address[4], nic->mac_address[5]);
 
     // Enable receive and transmit
     outw(nic->io_base + RTL8139_REG_COMMAND, RTL8139_CMD_RX_ENABLE | RTL8139_CMD_TX_ENABLE);

source/includes/filesystems/vfs.h

@@ -11,8 +11,7 @@
 #ifndef VFS_H
 #define VFS_H
 
-#include <basics.h>
-#include <stdint.h>
+#include <graphics.h>
 #include <ahci.h>
 #include <filesystems/fat16.h>
 

source/includes/graphics.h

@@ -9,14 +9,15 @@
  * 
  */
 #ifndef __GRAPHICS_H_
-#define __GRAPHICS_H_ 1
+#define __GRAPHICS_H_
 
 #include <stdint.h>
 #include <stddef.h>
 #include <stdarg.h>
 #include <stdbool.h>
 #include <basics.h>
 #include <strings.h>
+#include <stream.h>
 
 // ANSI color codes for text formatting
 #define reset_color  "\033[37m"
@@ -39,6 +40,9 @@ extern bool enable_logging;
 #define printfnoln(fmt, ...) \
     printfnoln_internal(__FILE__, __func__, __LINE__, fmt, ##__VA_ARGS__)
 
+#define eprintf(fmt, ...) \
+    eprintf_internal(__FILE__, __func__, __LINE__, fmt, ##__VA_ARGS__)
+
 
 /**
  * @brief Display a warning message.
@@ -89,8 +93,6 @@ void done(cstring message, cstring  file);
  */
 void putc(char c);
 
-
-
 /**
  * @brief Prints a value in binary format
  * 
@@ -130,14 +132,15 @@ void printfnoln_internal(cstring file, cstring func, int64 line, cstring format,
  * The newline flag controls whether a newline character ('\n') is printed
  * automatically at the end of the output.
  * 
+ * @param stream  The unix like STDOUT, STDERR.
  * @param file    The source file name of the caller (for logging context)
  * @param func    The function name of the caller (for logging context)
  * @param line    The source line number of the call (for logging context)
  * @param newline If true, appends a newline at the end of the formatted output
  * @param format  The printf-style format string
  * @param argp    The variable argument list (already started via va_start)
  */
-void vprintf_internal(cstring file, cstring func, int64 line, bool newline, cstring format, va_list argp);
+void vprintf_internal(stream_t stream, cstring file, cstring func, int64 line, bool newline, cstring format, va_list argp);
 
 /**
  * @brief Formats a string into a buffer using a va_list.

source/includes/kernel.h

@@ -42,6 +42,7 @@
 #include <image/targa.h>
 #include <executables/fwde.h>
 #include <fdlfcn.h>
+#include <stream.h>
 
 /**
  * @brief  Long story short: linker is a mole-rat and gives virtual addresses. But we asked the linker to allocate at this address, so we are spoofing its "security" to get the real memory address of kernel start and end.

source/includes/stream.h

@@ -0,0 +1,38 @@
+/**
+ * @file stream.h
+ * @author Pradosh ([email protected])
+ * @brief Unix like standard streams.
+ * @version 0.1
+ * @date 2026-01-03
+ * 
+ * @copyright Copyright (c) Pradosh 2026
+ * 
+ */
+#ifndef STREAM_H
+#define STREAM_H
+
+#include <stddef.h>
+
+typedef enum {
+    STDIN  = 0,
+    STDOUT = 1,
+    STDERR = 2
+} stream_t;
+
+void stream_init(void);
+
+/**
+ * @brief Redirect output to a file.
+ * 
+ * @param s the stream type.
+ * @param file If file is 'null' then output will be in terminal.
+ */
+// void stream_set_file(stream_t s, vfs_file_t* file);
+
+
+void stream_write(stream_t s, const char* buf, size_t len);
+
+
+void stream_putc(stream_t s, char c);
+
+#endif

source/kernel/C/cpuid.c

@@ -81,7 +81,7 @@ void print_L1_cache_info() {
     int32 eax, ebx, ecx, edx;
     cpuid(0x80000006, &eax, &ebx, &ecx, &edx);
     if ((edx & 0xFF) == 0) {
-        print("L1 Cache not present.\n");
+        printf("L1 Cache not present.");
         return;
     }
     printf("CPU Line Size: %d B, Assoc. Type: %d; Cache Size: %d KB. (L1 INFO)", ecx & 0xff, (ecx >> 12) & 0x07, (ecx >> 16) & 0xffff);
@@ -94,7 +94,7 @@ void print_L2_cache_info() {
     int32 eax, ebx, ecx, edx;
     cpuid(0x80000006, &eax, &ebx, &ecx, &edx);
     if ((edx & 0xFF) == 0) {
-        print("L2 Cache not present.\n");
+        printf("L2 Cache not present.");
         return;
     }
     printf("CPU Line Size: %d B, Assoc. Type: %d; Cache Size: %d KB. (L2 INFO)", ecx & 0xff, (ecx >> 12) & 0x0F, (ecx >> 16) & 0xFFFF);
@@ -107,7 +107,7 @@ void print_L3_cache_info() {
     int32 eax, ebx, ecx, edx;
     cpuid(0x80000006, &eax, &ebx, &ecx, &edx);
     if ((edx & 0xFF) == 0) {
-        print("L3 Cache not present.\n");
+        printf("L3 Cache not present.");
         return;
     }
     printf("CPU Line Size: %d B, Assoc. Type: %d; Cache Size: %d KB. (L3 INFO)", edx & 0xff, (edx >> 12) & 0x0F, (edx >> 16) & 0xFFFF);

source/kernel/C/kernel.c

@@ -120,6 +120,7 @@ void main(void) {
         hcf2();
     }
 
+    stream_init();
     // Fetch the first framebuffer.
     framebuffer = framebuffer_request.response->framebuffers[0];
 
@@ -186,8 +187,7 @@ void main(void) {
 
     probe_pci();
 
-    print(public_key);
-    print("\n");
+    printf(public_key);
 
     printf("Display Resolution: %dx%d (%d) pixels. Pitch: %d", framebuffer->width, framebuffer->height, framebuffer->width*framebuffer->height, framebuffer->pitch);
 
@@ -244,7 +244,7 @@ void main(void) {
 }
 
 /**
- * @brief The basic print function.
+ * @brief The basic raw print function. (DO NOT HANDLE STREAMS)
  * 
  * @param msg The message to be printed
  */

source/kernel/C/logger.c

@@ -13,6 +13,7 @@
 
 static const char hex_digits[] = "0123456789abcdef";
 static const char caps_hex_digits[] = "0123456789ABCDEF";
+static stream_t printf_stream;
 
 string last_filename = "unknown"; // for warn, info, err, done
 string last_print_file = "unknown";
@@ -31,11 +32,7 @@ bool enable_logging = true;
  */
 void warn(cstring message, cstring file) {
     cstring warn_message = yellow_color "[***] → " reset_color;
-    print(warn_message);
-    print(message);
-    print(" at " blue_color);
-    print(file);
-    print(reset_color "\n");
+    printf("%s%s at " blue_color "%s" reset_color, warn_message, message, file);
 
     debug_print(warn_message);
     debug_print(message);
@@ -56,11 +53,7 @@ void warn(cstring message, cstring file) {
  */
 void error(cstring message, cstring file) {
     cstring err_message = red_color "[***] → " reset_color;
-    print(err_message);
-    print(message);
-    print(" at " blue_color);
-    print(file);
-    print(reset_color "\n");
+    eprintf("%s%s at " blue_color "%s" reset_color, err_message, message, file);
 
     debug_print(err_message);
     debug_print(message);
@@ -81,11 +74,7 @@ void error(cstring message, cstring file) {
  */
 void info(cstring message, cstring file) {
     cstring info_message = blue_color "[***] → " reset_color;
-    print(info_message);
-    print(message);
-    print(" at " blue_color);
-    print(file);
-    print(reset_color "\n");
+    printf("%s%s at " blue_color "%s" reset_color, info_message, message, file);
 
     debug_print(info_message);
     debug_print(message);
@@ -106,11 +95,7 @@ void info(cstring message, cstring file) {
  */
 void done(cstring message, cstring file) {
     cstring done_message = green_color "[***] → " reset_color;
-    print(done_message);
-    print(message);
-    print(" at " blue_color);
-    print(file);
-    print(reset_color "\n");
+    printf("%s%s at " blue_color "%s" reset_color, done_message, message, file);
 
     debug_print(done_message);
     debug_print(message);
@@ -128,10 +113,7 @@ void done(cstring message, cstring file) {
  * @note Internally using Flanterm's putchar function
  */
 void vputc(char c) {
-    char str[2];
-    str[0] = c;
-    str[1] = '\0';
-    print(str);
+    stream_putc(printf_stream, c);
 }
 
 void printdec_fmt(int num, int width, bool zero_pad)
@@ -250,13 +232,15 @@ static void printstr_fmt(const char* s, int width)
 }
 
 
-void vprintf_internal(cstring file, cstring func, int64 line, bool newline, cstring format, va_list argp) {
+void vprintf_internal(stream_t stream, cstring file, cstring func, int64 line, bool newline, cstring format, va_list argp) {
     if (enable_logging) {
         last_print_file = file;
         last_print_func = func;
         last_print_line = line;
     }
 
+    printf_stream = stream;
+
     while (*format != '\0') {
         if (*format == '%') {
             format++;
@@ -331,14 +315,21 @@ void vprintf_internal(cstring file, cstring func, int64 line, bool newline, cstr
 void printf_internal(cstring file, cstring func, int64 line, cstring format, ...) {
     va_list argp;
     va_start(argp, format);
-    vprintf_internal(file, func, line, true, format, argp);
+    vprintf_internal(STDOUT, file, func, line, true, format, argp);
     va_end(argp);
 }
 
 void printfnoln_internal(cstring file, cstring func, int64 line, cstring format, ...) {
     va_list argp;
     va_start(argp, format);
-    vprintf_internal(file, func, line, false, format, argp);
+    vprintf_internal(STDOUT, file, func, line, false, format, argp);
+    va_end(argp);
+}
+
+void eprintf_internal(cstring file, cstring func, int64 line, cstring format, ...) {
+    va_list argp;
+    va_start(argp, format);
+    vprintf_internal(STDERR, file, func, line, true, format, argp);
     va_end(argp);
 }
 

source/kernel/C/stream.c

@@ -0,0 +1,56 @@
+/**
+ * @file stream.c
+ * @author Pradosh ([email protected])
+ * @brief Unix like standard streams.
+ * @version 0.1
+ * @date 2026-01-03
+ * 
+ * @copyright Copyright (c) Pradosh 2026
+ * 
+ */
+
+#include <stream.h>
+#include <graphics.h>   // flanterm
+#include <basics.h>
+#include <filesystems/vfs.h>
+
+extern struct flanterm_context* ft_ctx;
+
+typedef struct {
+    vfs_file_t* file;   // NULL → terminal
+} stream_impl_t;
+
+static stream_impl_t streams[3];
+
+void stream_init(void)
+{
+    streams[STDIN].file  = NULL;
+    streams[STDOUT].file = NULL;
+    streams[STDERR].file = NULL;
+}
+
+void stream_set_file(stream_t s, vfs_file_t* file)
+{
+    streams[s].file = file;
+}
+
+void stream_write(stream_t s, const char* buf, size_t len)
+{
+    if (!buf || len == 0) return;
+
+    stream_impl_t* st = &streams[s];
+
+    if (st->file) {
+        vfs_write(st->file, (const uint8_t*)buf, len);
+    } else {
+        flanterm_write(ft_ctx, buf, len);
+    }
+}
+
+void stream_putc(stream_t s, char c)
+{
+    char str[2];
+    str[0] = c;
+    str[1] = '\0';
+    stream_write(s, str, 1);
+}