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9940881f6d
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ba58c1579c
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/*
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* linux/init/main.c
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*
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* (C) 1991 Linus Torvalds
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*/
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#define __LIBRARY__
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#include <unistd.h>
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#include <time.h>
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/*
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* we need this inline - forking from kernel space will result
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* in NO COPY ON WRITE (!!!), until an execve is executed. This
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* is no problem, but for the stack. This is handled by not letting
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* main() use the stack at all after fork(). Thus, no function
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* calls - which means inline code for fork too, as otherwise we
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* would use the stack upon exit from 'fork()'.
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*
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* Actually only pause and fork are needed inline, so that there
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* won't be any messing with the stack from main(), but we define
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* some others too.
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*/
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__always_inline _syscall0(int,fork)
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__always_inline _syscall0(int,pause)
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__always_inline _syscall1(int,setup,void *,BIOS)
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__always_inline _syscall0(int,sync)
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#include <linux/tty.h>
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#include <linux/sched.h>
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#include <linux/head.h>
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#include <asm/system.h>
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#include <asm/io.h>
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#include <stddef.h>
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#include <stdarg.h>
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#include <fcntl.h>
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#include <sys/types.h>
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#include <linux/fs.h>
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static char printbuf[1024];
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extern int vsprintf();
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extern void init(void);
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extern void blk_dev_init(void);
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extern void chr_dev_init(void);
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extern void hd_init(void);
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extern void floppy_init(void);
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extern void mem_init(long start, long end);
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extern long rd_init(long mem_start, int length);
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extern long kernel_mktime(struct tm * tm);
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extern long startup_time;
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/*
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* This is set up by the setup-routine at boot-time
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*/
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#define EXT_MEM_K (*(unsigned short *)0x90002)
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#define DRIVE_INFO (*(struct drive_info *)0x90080)
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#define ORIG_ROOT_DEV (*(unsigned short *)0x901FC)
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/*
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* Yeah, yeah, it's ugly, but I cannot find how to do this correctly
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* and this seems to work. I anybody has more info on the real-time
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* clock I'd be interested. Most of this was trial and error, and some
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* bios-listing reading. Urghh.
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*/
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#define CMOS_READ(addr) ({ \
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outb_p(0x80|addr,0x70); \
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inb_p(0x71); \
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})
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#define BCD_TO_BIN(val) ((val)=((val)&15) + ((val)>>4)*10)
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static void time_init(void)
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{
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struct tm time;
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do {
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time.tm_sec = CMOS_READ(0);
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time.tm_min = CMOS_READ(2);
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time.tm_hour = CMOS_READ(4);
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time.tm_mday = CMOS_READ(7);
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time.tm_mon = CMOS_READ(8);
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time.tm_year = CMOS_READ(9);
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} while (time.tm_sec != CMOS_READ(0));
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BCD_TO_BIN(time.tm_sec);
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BCD_TO_BIN(time.tm_min);
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BCD_TO_BIN(time.tm_hour);
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BCD_TO_BIN(time.tm_mday);
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BCD_TO_BIN(time.tm_mon);
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BCD_TO_BIN(time.tm_year);
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time.tm_mon--;
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startup_time = kernel_mktime(&time);
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}
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static long memory_end = 0;
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static long buffer_memory_end = 0;
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static long main_memory_start = 0;
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struct drive_info { char dummy[32]; } drive_info;
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void main(void) /* This really IS void, no error here. */
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{ /* The startup routine assumes (well, ...) this */
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/*
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* Interrupts are still disabled. Do necessary setups, then
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* enable them
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*/
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ROOT_DEV = ORIG_ROOT_DEV;
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__asm__ volatile ("cld"); /* by wyj */
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drive_info = DRIVE_INFO;
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memory_end = (1<<20) + (EXT_MEM_K<<10);
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memory_end &= 0xfffff000;
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if (memory_end > 16*1024*1024)
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memory_end = 16*1024*1024;
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if (memory_end > 12*1024*1024)
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buffer_memory_end = 4*1024*1024;
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else if (memory_end > 6*1024*1024)
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buffer_memory_end = 2*1024*1024;
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else
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buffer_memory_end = 1*1024*1024;
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main_memory_start = buffer_memory_end;
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#ifdef RAMDISK
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main_memory_start += rd_init(main_memory_start, RAMDISK*1024);
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#endif
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mem_init(main_memory_start,memory_end);
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trap_init();
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blk_dev_init();
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chr_dev_init();
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tty_init();
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time_init();
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sched_init();
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buffer_init(buffer_memory_end);
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hd_init();
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floppy_init();
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sti();
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move_to_user_mode();
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if (!fork()) { /* we count on this going ok */
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init();
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}
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/*
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* NOTE!! For any other task 'pause()' would mean we have to get a
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* signal to awaken, but task0 is the sole exception (see 'schedule()')
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* as task 0 gets activated at every idle moment (when no other tasks
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* can run). For task0 'pause()' just means we go check if some other
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* task can run, and if not we return here.
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*/
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for(;;) pause();
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}
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static int printf(const char *fmt, ...)
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{
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va_list args;
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int i;
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va_start(args, fmt);
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write(1,printbuf,i=vsprintf(printbuf, fmt, args));
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va_end(args);
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return i;
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}
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static char * argv_rc[] = { "/bin/sh", NULL };
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static char * envp_rc[] = { "HOME=/", NULL, NULL };
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static char * argv[] = { "-/bin/sh",NULL };
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static char * envp[] = { "HOME=/usr/root", NULL, NULL };
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void init(void)
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{
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int pid,i;
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setup((void *) &drive_info);
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(void) open("/dev/tty0",O_RDWR,0);
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(void) dup(0);
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(void) dup(0);
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printf("%d buffers = %d bytes buffer space\n\r",NR_BUFFERS,
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NR_BUFFERS*BLOCK_SIZE);
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printf("Free mem: %d bytes\n\r",memory_end-main_memory_start);
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if (!(pid=fork())) {
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close(0);
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if (open("/etc/rc",O_RDONLY,0))
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_exit(1);
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execve("/bin/sh",argv_rc,envp_rc);
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_exit(2);
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}
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if (pid>0)
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while (pid != wait(&i))
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/* nothing */;
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while (1) {
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if ((pid=fork())<0) {
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printf("Fork failed in init\r\n");
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continue;
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}
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if (!pid) {
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close(0);close(1);close(2);
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setsid();
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(void) open("/dev/tty0",O_RDWR,0);
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(void) dup(0);
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(void) dup(0);
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_exit(execve("/bin/sh",argv,envp));
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}
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while (1)
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if (pid == wait(&i))
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break;
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printf("\n\rchild %d died with code %04x\n\r",pid,i);
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sync();
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}
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_exit(0); /* NOTE! _exit, not exit() */
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}
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