Initial commit: SUB-OS 64-Bit Production Monolithic Operating System with LazyBox userland suite

kernel/printk.c

@@ -0,0 +1,91 @@
+#include <kernel/printk.h>
+#include <drivers/tty.h>
+#include <drivers/serial.h>
+#include <lib/printf.h>
+#include <lib/string.h>
+#include <kernel/sync.h>
+
+#define DMESG_BUFFER_SIZE 65536 // 64 KB Ring Buffer
+
+static char dmesg_buffer[DMESG_BUFFER_SIZE];
+static size_t dmesg_head = 0;
+static size_t dmesg_total = 0;
+static spinlock_t printk_lock = SPINLOCK_INIT;
+
+void printk_init(void) {
+    memset(dmesg_buffer, 0, sizeof(dmesg_buffer));
+    dmesg_head = 0;
+    dmesg_total = 0;
+}
+
+static void dmesg_append(const char* str, size_t len) {
+    for (size_t i = 0; i < len; i++) {
+        dmesg_buffer[dmesg_head] = str[i];
+        dmesg_head = (dmesg_head + 1) % DMESG_BUFFER_SIZE;
+        if (dmesg_total < DMESG_BUFFER_SIZE) {
+            dmesg_total++;
+        }
+    }
+}
+
+int vprintk(const char* fmt, va_list args) {
+    char buffer[1024];
+    int len = vsnprintf(buffer, sizeof(buffer), fmt, args);
+    if (len <= 0) return 0;
+
+    spin_lock(&printk_lock);
+
+    // Skip loglevel prefix if present (e.g. "\0016")
+    const char* display_ptr = buffer;
+    if (buffer[0] == '\001' && buffer[1] >= '0' && buffer[1] <= '7') {
+        display_ptr += 2;
+        len -= 2;
+    }
+
+    // 1. Output to active TTY console
+    tty_write(display_ptr, (size_t)len);
+
+    // 2. Output to COM1 serial port for host debugging
+    for (int i = 0; i < len; i++) {
+        serial_write_char(display_ptr[i]);
+    }
+
+    // 3. Store in kernel dmesg ring buffer
+    dmesg_append(display_ptr, (size_t)len);
+
+    spin_unlock(&printk_lock);
+    return len;
+}
+
+int printk(const char* fmt, ...) {
+    va_list args;
+    va_start(args, fmt);
+    int ret = vprintk(fmt, args);
+    va_end(args);
+    return ret;
+}
+
+int kprintf(const char* fmt, ...) {
+    va_list args;
+    va_start(args, fmt);
+    int ret = vprintk(fmt, args);
+    va_end(args);
+    return ret;
+}
+
+void dmesg_dump(void) {
+    spin_lock(&printk_lock);
+    if (dmesg_total < DMESG_BUFFER_SIZE) {
+        tty_write(dmesg_buffer, dmesg_total);
+    } else {
+        // Output from head to end, then 0 to head
+        tty_write(dmesg_buffer + dmesg_head, DMESG_BUFFER_SIZE - dmesg_head);
+        tty_write(dmesg_buffer, dmesg_head);
+    }
+    spin_unlock(&printk_lock);
+}
+
+const char* dmesg_get_buffer(size_t* size_out) {
+    if (size_out) *size_out = dmesg_total;
+    return dmesg_buffer;
+}