1 files changed, 147 insertions, 0 deletions
diff --git a/linux/init/main.c b/linux/init/main.c
new file mode 100644
index 0000000..1192119
--- /dev/null
+++ b/linux/init/main.c
@@ -0,0 +1,147 @@
+#define __LIBRARY__
+#include <unistd.h>
+#include <time.h>
+
+/*
+ * we need this inline - forking from kernel space will result
+ * in NO COPY ON WRITE (!!!), until an execve is executed. This
+ * is no problem, but for the stack. This is handled by not letting
+ * main() use the stack at all after fork(). Thus, no function
+ * calls - which means inline code for fork too, as otherwise we
+ * would use the stack upon exit from 'fork()'.
+ *
+ * Actually only pause and fork are needed inline, so that there
+ * won't be any messing with the stack from main(), but we define
+ * some others too.
+ */
+static inline _syscall0(int,fork)
+static inline _syscall0(int,pause)
+static inline _syscall0(int,setup)
+static inline _syscall0(int,sync)
+
+#include <linux/tty.h>
+#include <linux/sched.h>
+#include <linux/head.h>
+#include <asm/system.h>
+#include <asm/io.h>
+
+#include <stddef.h>
+#include <stdarg.h>
+#include <unistd.h>
+#include <fcntl.h>
+#include <sys/types.h>
+
+#include <linux/fs.h>
+
+static char printbuf[1024];
+
+extern int vsprintf();
+extern void init(void);
+extern void hd_init(void);
+extern long kernel_mktime(struct tm * tm);
+extern long startup_time;
+
+/*
+ * Yeah, yeah, it's ugly, but I cannot find how to do this correctly
+ * and this seems to work. I anybody has more info on the real-time
+ * clock I'd be interested. Most of this was trial and error, and some
+ * bios-listing reading. Urghh.
+ */
+
+#define CMOS_READ(addr) ({ \
+outb_p(0x80|addr,0x70); \
+inb_p(0x71); \
+})
+
+#define BCD_TO_BIN(val) ((val)=((val)&15) + ((val)>>4)*10)
+
+static void time_init(void)
+{
+	struct tm time;
+
+	do {
+		time.tm_sec = CMOS_READ(0);
+		time.tm_min = CMOS_READ(2);
+		time.tm_hour = CMOS_READ(4);
+		time.tm_mday = CMOS_READ(7);
+		time.tm_mon = CMOS_READ(8)-1;
+		time.tm_year = CMOS_READ(9);
+	} while (time.tm_sec != CMOS_READ(0));
+	BCD_TO_BIN(time.tm_sec);
+	BCD_TO_BIN(time.tm_min);
+	BCD_TO_BIN(time.tm_hour);
+	BCD_TO_BIN(time.tm_mday);
+	BCD_TO_BIN(time.tm_mon);
+	BCD_TO_BIN(time.tm_year);
+	startup_time = kernel_mktime(&time);
+}
+
+void main(void)		/* This really IS void, no error here. */
+{			/* The startup routine assumes (well, ...) this */
+/*
+ * Interrupts are still disabled. Do necessary setups, then
+ * enable them
+ */
+	time_init();
+	tty_init();
+	trap_init();
+	sched_init();
+	buffer_init();
+	hd_init();
+	sti();
+	move_to_user_mode();
+	if (!fork()) {		/* we count on this going ok */
+		init();
+	}
+/*
+ *   NOTE!!   For any other task 'pause()' would mean we have to get a
+ * signal to awaken, but task0 is the sole exception (see 'schedule()')
+ * as task 0 gets activated at every idle moment (when no other tasks
+ * can run). For task0 'pause()' just means we go check if some other
+ * task can run, and if not we return here.
+ */
+	for(;;) pause();
+}
+
+static int printf(const char *fmt, ...)
+{
+	va_list args;
+	int i;
+
+	va_start(args, fmt);
+	write(1,printbuf,i=vsprintf(printbuf, fmt, args));
+	va_end(args);
+	return i;
+}
+
+static char * argv[] = { "-",NULL };
+static char * envp[] = { "HOME=/usr/root", NULL };
+
+void init(void)
+{
+	int i,j;
+
+	setup();
+	if (!fork())
+		_exit(execve("/bin/update",NULL,NULL));
+	(void) open("/dev/tty0",O_RDWR,0);
+	(void) dup(0);
+	(void) dup(0);
+	printf("%d buffers = %d bytes buffer space\n\r",NR_BUFFERS,
+		NR_BUFFERS*BLOCK_SIZE);
+	printf(" Ok.\n\r");
+	if ((i=fork())<0)
+		printf("Fork failed in init\r\n");
+	else if (!i) {
+		close(0);close(1);close(2);
+		setsid();
+		(void) open("/dev/tty0",O_RDWR,0);
+		(void) dup(0);
+		(void) dup(0);
+		_exit(execve("/bin/sh",argv,envp));
+	}
+	j=wait(&i);
+	printf("child %d died with code %04x\n",j,i);
+	sync();
+	_exit(0);	/* NOTE! _exit, not exit() */
+}