first usable version of kernel and commands

After an year of hard work, this is a first "usable" version of Jehanne.

sys/src/kern/port/devtab.c

@@ -0,0 +1,103 @@
+/*
+ * Stub.
+ */
+#include "u.h"
+#include "../port/lib.h"
+#include "mem.h"
+#include "dat.h"
+#include "fns.h"
+#include "../port/error.h"
+
+extern Dev* devtab[];
+
+void
+devtabreset(void)
+{
+	int i;
+	Dev *d;
+
+	for(i = 0; devtab[i] != nil; i++){
+		d = devtab[i];
+		d->reset();
+	}
+}
+
+void
+devtabinit(void)
+{
+	int i;
+
+	for(i = 0; devtab[i] != nil; i++)
+		devtab[i]->init();
+}
+
+void
+devtabshutdown(void)
+{
+	int i;
+
+	/*
+	 * Shutdown in reverse order.
+	 */
+	for(i = 0; devtab[i] != nil; i++)
+		;
+	for(i--; i >= 0; i--)
+		devtab[i]->shutdown();
+}
+
+
+Dev*
+devtabget(int dc, int user)
+{
+	int i;
+
+	for(i = 0; devtab[i] != nil; i++){
+		if(devtab[i]->dc == dc)
+			return devtab[i];
+	}
+
+	if(user == 0)
+		panic("devtabget %C\n", dc);
+
+	return nil;
+}
+
+Dev*
+devbyname(char *name)
+{
+	int i;
+
+	for(i = 0; devtab[i] != nil; i++)
+		if(strcmp(devtab[i]->name, name) == 0)
+			return devtab[i];
+	return nil;
+}
+
+long
+devtabread(Chan* _1, void* buf, long n, int64_t off)
+{
+	int i;
+	Dev *dev;
+	char *alloc, *e, *p;
+
+	alloc = malloc(READSTR);
+	if(alloc == nil)
+		error(Enomem);
+
+	p = alloc;
+	e = p + READSTR;
+	for(i = 0; devtab[i] != nil; i++){
+		dev = devtab[i];
+		p = seprint(p, e, "#%C %s\n", dev->dc, dev->name);
+	}
+
+	if(waserror()){
+		free(alloc);
+		nexterror();
+	}
+	n = readstr(off, buf, n, alloc);
+	free(alloc);
+	poperror();
+
+	return n;
+}