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1.1 root 1: #define __LIBRARY__
2: #include <unistd.h>
3: #include <time.h>
4:
5: /*
6: * we need this inline - forking from kernel space will result
7: * in NO COPY ON WRITE (!!!), until an execve is executed. This
8: * is no problem, but for the stack. This is handled by not letting
9: * main() use the stack at all after fork(). Thus, no function
10: * calls - which means inline code for fork too, as otherwise we
11: * would use the stack upon exit from 'fork()'.
12: *
13: * Actually only pause and fork are needed inline, so that there
14: * won't be any messing with the stack from main(), but we define
15: * some others too.
16: */
17: static inline _syscall0(int,fork)
18: static inline _syscall0(int,pause)
19: static inline _syscall0(int,setup)
20: static inline _syscall0(int,sync)
21:
22: #include <linux/tty.h>
23: #include <linux/sched.h>
24: #include <linux/head.h>
25: #include <asm/system.h>
26: #include <asm/io.h>
27:
28: #include <stddef.h>
29: #include <stdarg.h>
30: #include <unistd.h>
31: #include <fcntl.h>
32: #include <sys/types.h>
33:
34: #include <linux/fs.h>
35:
36: static char printbuf[1024];
37:
38: extern int vsprintf();
39: extern void init(void);
40: extern void hd_init(void);
41: extern long kernel_mktime(struct tm * tm);
42: extern long startup_time;
43:
44: /*
45: * Yeah, yeah, it's ugly, but I cannot find how to do this correctly
46: * and this seems to work. I anybody has more info on the real-time
47: * clock I'd be interested. Most of this was trial and error, and some
48: * bios-listing reading. Urghh.
49: */
50:
51: #define CMOS_READ(addr) ({ \
52: outb_p(0x80|addr,0x70); \
53: inb_p(0x71); \
54: })
55:
56: #define BCD_TO_BIN(val) ((val)=((val)&15) + ((val)>>4)*10)
57:
58: static void time_init(void)
59: {
60: struct tm time;
61:
62: do {
63: time.tm_sec = CMOS_READ(0);
64: time.tm_min = CMOS_READ(2);
65: time.tm_hour = CMOS_READ(4);
66: time.tm_mday = CMOS_READ(7);
67: time.tm_mon = CMOS_READ(8)-1;
68: time.tm_year = CMOS_READ(9);
69: } while (time.tm_sec != CMOS_READ(0));
70: BCD_TO_BIN(time.tm_sec);
71: BCD_TO_BIN(time.tm_min);
72: BCD_TO_BIN(time.tm_hour);
73: BCD_TO_BIN(time.tm_mday);
74: BCD_TO_BIN(time.tm_mon);
75: BCD_TO_BIN(time.tm_year);
76: startup_time = kernel_mktime(&time);
77: }
78:
79: void main(void) /* This really IS void, no error here. */
80: { /* The startup routine assumes (well, ...) this */
81: /*
82: * Interrupts are still disabled. Do necessary setups, then
83: * enable them
84: */
85: time_init();
86: tty_init();
87: trap_init();
88: sched_init();
89: buffer_init();
90: hd_init();
91: sti();
92: move_to_user_mode();
93: if (!fork()) { /* we count on this going ok */
94: init();
95: }
96: /*
97: * NOTE!! For any other task 'pause()' would mean we have to get a
98: * signal to awaken, but task0 is the sole exception (see 'schedule()')
99: * as task 0 gets activated at every idle moment (when no other tasks
100: * can run). For task0 'pause()' just means we go check if some other
101: * task can run, and if not we return here.
102: */
103: for(;;) pause();
104: }
105:
106: static int printf(const char *fmt, ...)
107: {
108: va_list args;
109: int i;
110:
111: va_start(args, fmt);
112: write(1,printbuf,i=vsprintf(printbuf, fmt, args));
113: va_end(args);
114: return i;
115: }
116:
117: static char * argv[] = { "-",NULL };
118: static char * envp[] = { "HOME=/usr/root", NULL };
119:
120: void init(void)
121: {
122: int i,j;
123:
124: setup();
125: if (!fork())
126: _exit(execve("/bin/update",NULL,NULL));
127: (void) open("/dev/tty0",O_RDWR,0);
128: (void) dup(0);
129: (void) dup(0);
130: printf("%d buffers = %d bytes buffer space\n\r",NR_BUFFERS,
131: NR_BUFFERS*BLOCK_SIZE);
132: printf(" Ok.\n\r");
133: if ((i=fork())<0)
134: printf("Fork failed in init\r\n");
135: else if (!i) {
136: close(0);close(1);close(2);
137: setsid();
138: (void) open("/dev/tty0",O_RDWR,0);
139: (void) dup(0);
140: (void) dup(0);
141: _exit(execve("/bin/sh",argv,envp));
142: }
143: j=wait(&i);
144: printf("child %d died with code %04x\n",j,i);
145: sync();
146: _exit(0); /* NOTE! _exit, not exit() */
147: }
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