feat: extend alarmdefault and argecho

user/consolereader1.c

@@ -0,0 +1,37 @@
+#include "ulib.h"
+
+/*
+ * Boot-spawned independently of consolereader2.c (see kmain.c's spawnUser
+ * calls) -- like namedreader.c/namedwriter.c, neither process's pid, argv,
+ * or fd table ever mentions the other. Both simply read fd 0, which every
+ * process gets for free (vfs.c's vfsFdInit) as its own console reader queue
+ * (keyboard.h) rather than a single kernel-wide buffer: proving that two
+ * completely unrelated processes reading "the keyboard" each get their own
+ * independent copy of every keystroke instead of racing each other for it.
+ *
+ * kmain.c's consoleInjectorThread fires exactly one synthetic keystroke a
+ * few hundred milliseconds after boot (there is no automated way to drive a
+ * real PS/2 device under headless QEMU, see its own comment) through the
+ * same keyboardHandleScancode the real IRQ handler calls -- so this process
+ * has to genuinely park in userRead across many timer ticks and be woken
+ * later, not just win a race against a byte that was already queued.
+ */
+
+int main(void)
+{
+    print("consolereader1: start, pid=");
+    printDec(userGetpid());
+    print(", blocking on fd 0\n");
+
+    char c = 0;
+    long got = userRead(0, &c, 1);
+    if (got != 1) {
+        print("consolereader1: FAIL read\n");
+        return 1;
+    }
+
+    print("consolereader1: got byte '");
+    userWrite(1, &c, 1);
+    print("' -> console-fanout-1-ok\n");
+    return 0;
+}