feat: extend keyboard with ConsoleReader and keyboardForegroundPgid

src/keyboard.c

@@ -1,8 +1,26 @@
 #include "keyboard.h"
 #include "ports.h"
+#include "ring.h"
+#include "sched.h"
+#include "signal.h"
 
 #define keyboardData 0x60
 
+/* Left-Ctrl's own PS/2 Set 1 make/break scancodes -- exactly the same
+   convention keyboardHandleScancode already had for Shift (0x2A/0x36 make,
+   0xAA/0xB6 break): held state tracked in a single bool, never forwarded
+   to scancodeLower/scancodeUpper (there is no printable character for a
+   modifier key on its own). */
+#define scancodeLeftCtrlMake  0x1D
+#define scancodeLeftCtrlBreak 0x9D
+
+static bool ctrlHeld;
+
+/* Real tcsetpgrp(3)'s target -- see keyboard.h's own doc comment for why 0
+   (keyboardInit's initial value) safely means "nobody yet" with no extra
+   sentinel needed. */
+static uint32 foregroundPgid;
+
 static const char scancodeLower[128] = {
     0, 27, '1', '2', '3', '4', '5', '6', '7', '8', '9', '0', '-', '=', '\b',
     '\t', 'q', 'w', 'e', 'r', 't', 'y', 'u', 'i', 'o', 'p', '[', ']', '\n',
@@ -19,32 +37,138 @@ static const char scancodeUpper[128] = {
     '*', 0, ' ', 0
 };
 
-#define keyBufferSize 128
-static volatile char keyBuffer[keyBufferSize];
-static volatile uint32 bufferHead;
-static volatile uint32 bufferTail;
 static bool shiftHeld;
 
+#define consoleReaderBufferSize 32
+
+typedef struct ConsoleReader {
+    RingBuffer ring;
+    uint8 backing[consoleReaderBufferSize];
+    bool used;
+} ConsoleReader;
+
+static ConsoleReader consoleReaders[maxConsoleReaders];
+
 void keyboardInit(void)
 {
-    bufferHead = 0;
-    bufferTail = 0;
     shiftHeld = false;
+    ctrlHeld = false;
+    foregroundPgid = 0;
+    for (int i = 0; i < maxConsoleReaders; i++)
+        consoleReaders[i].used = false;
 }
 
-static void pushChar(char c)
+void keyboardSetForegroundPgid(uint32 pgid)
 {
-    uint32 next = (bufferHead + 1) % keyBufferSize;
+    foregroundPgid = pgid;
-    if (next != bufferTail) {
+}
-        keyBuffer[bufferHead] = c;
+
-        bufferHead = next;
+uint32 keyboardForegroundPgid(void)
+{
+    return foregroundPgid;
+}
+
+int keyboardOpenReader(void)
+{
+    for (int i = 0; i < maxConsoleReaders; i++) {
+        if (!consoleReaders[i].used) {
+            ringInit(&consoleReaders[i].ring, consoleReaders[i].backing, consoleReaderBufferSize);
+            consoleReaders[i].used = true;
+            return i;
+        }
+    }
+    return consoleReaderInvalid;
+}
+
+static ConsoleReader* readerAt(int handle)
+{
+    if (handle < 0 || handle >= maxConsoleReaders)
+        return nullptr;
+    if (!consoleReaders[handle].used)
+        return nullptr;
+    return &consoleReaders[handle];
+}
+
+void keyboardCloseReader(int handle)
+{
+    ConsoleReader* r = readerAt(handle);
+    if (!r)
+        return;
+    r->used = false;
+}
+
+int64 keyboardReaderRead(int handle, void* buffer, uint64 length)
+{
+    ConsoleReader* r = readerAt(handle);
+    if (!r)
+        return -1;
+    if (length == 0)
+        return 0;
+    if (ringIsEmpty(&r->ring))
+        return -1;
+
+    usize got = ringRead(&r->ring, (uint8*)buffer, (usize)length);
+    return (int64)got;
+}
+
+int64 keyboardReaderReadBlocking(int handle, void* buffer, uint64 length)
+{
+    ConsoleReader* r = readerAt(handle);
+    if (!r)
+        return -1;
+
+    for (;;) {
+        int64 result = keyboardReaderRead(handle, buffer, length);
+        if (result != -1)
+            return result;
+
+        schedBlockCurrent((const void*)r);
+        halt();
     }
 }
 
-void keyboardHandler(void)
+const void* keyboardReaderChannel(int handle)
 {
-    uint8 scancode = inb(keyboardData);
+    return (const void*)readerAt(handle);
+}
 
+bool keyboardReaderHasData(int handle)
+{
+    ConsoleReader* r = readerAt(handle);
+    if (!r)
+        return false;
+    return !ringIsEmpty(&r->ring);
+}
+
+/*
+ * Real cooked-mode tty line discipline's INTR/SUSP characters (termios's
+ * VINTR/VSUSP, both Ctrl-<letter> by default): keyboardHandleScancode now
+ * tracks left-Ctrl as a THIRD modifier alongside Shift, and when it is held
+ * for a 'c'/'C' or 'z'/'Z' keypress, the resulting sigInt/sigTstp is
+ * delivered to the WHOLE foreground process group (sigRaiseGroup, signal.h)
+ * -- keyboardSetForegroundPgid's target, real tcsetpgrp(3)'s own job --
+ * instead of the raw byte ever reaching any consoleReaders fan-out below.
+ * This is the scope real Ctrl-C actually has: every process in the
+ * foreground job, not "whichever process happens to be reading fd 0 right
+ * now" -- a BACKGROUND job (a different pgid, one keyboardSetForegroundPgid
+ * was never told about) must never be disturbed by a keypress aimed at
+ * whatever IS currently in the foreground, the same isolation a real shell's
+ * job control gives. kmain.c's pgroupfg.c/pgroupbg.c is the live ring-3
+ * proof: pgroupfg (foreground, no handler installed) actually dies to the
+ * injected Ctrl-C's default-Terminate disposition, while pgroupbg
+ * (deliberately left in a DIFFERENT group) proves itself still alive and
+ * responsive afterwards.
+ */
+void keyboardHandleScancode(uint8 scancode)
+{
+    if (scancode == scancodeLeftCtrlMake) {
+        ctrlHeld = true;
+        return;
+    }
+    if (scancode == scancodeLeftCtrlBreak) {
+        ctrlHeld = false;
+        return;
+    }
     if (scancode == 0x2A || scancode == 0x36) {
         shiftHeld = true;
         return;
@@ -57,21 +181,39 @@ void keyboardHandler(void)
         return;
 
     char c = shiftHeld ? scancodeUpper[scancode] : scancodeLower[scancode];
-    if (c)
+    if (!c)
-        pushChar(c);
+        return;
+
+    /* Consumed here, never forwarded as data below -- exactly like a real
+       cooked-mode terminal driver never hands a reading program the raw
+       0x03/0x1A byte either. siCodeKernel/0: no sending PROCESS raised
+       this, the keyboard itself did, the same "kernel, not a process, is
+       the source" reasoning schedule()'s own SIGALRM raise already uses
+       for siCodeKernel. Harmless no-op (sigRaiseGroup's own contract) if
+       foregroundPgid currently names no live group at all. */
+    if (ctrlHeld && (c == 'c' || c == 'C')) {
+        sigRaiseGroup(foregroundPgid, sigInt, siCodeKernel, 0);
+        return;
+    }
+    if (ctrlHeld && (c == 'z' || c == 'Z')) {
+        sigRaiseGroup(foregroundPgid, sigTstp, siCodeKernel, 0);
+        return;
+    }
+
+    for (int i = 0; i < maxConsoleReaders; i++) {
+        if (!consoleReaders[i].used)
+            continue;
+        ringPush(&consoleReaders[i].ring, (uint8)c);
+        /* Mirrors pipeWrite's wake-after-write: harmless no-op (schedWakeChannel's
+           own contract) if nobody is currently blocked on this particular
+           reader's channel. */
+        schedWakeChannel((const void*)&consoleReaders[i]);
+    }
+    schedWakeChannel(schedPollChannel());
 }
 
-bool keyboardHasChar(void)
+void keyboardHandler(void)
 {
-    return bufferHead != bufferTail;
+    uint8 scancode = inb(keyboardData);
-}
+    keyboardHandleScancode(scancode);
-
-char keyboardReadChar(void)
-{
-    while (bufferHead == bufferTail)
-        __asm__ volatile("sti; hlt");
-
-    char c = keyBuffer[bufferTail];
-    bufferTail = (bufferTail + 1) % keyBufferSize;
-    return c;
 }