path: root/init/init.c

/*
 *  linux/init/init.c
 *
 *  Copyright (C) 1991, 1992  Linus Torvalds
 */

#include <stdarg.h>

#include <asm/system.h>
#include <asm/io.h>

#include <linux/types.h>
#include <linux/fcntl.h>
#include <linux/config.h>
#include <linux/sched.h>
#include <linux/tty.h>
#include <linux/head.h>
#include <linux/unistd.h>
#include <linux/string.h>
#include <linux/timer.h>
#include <linux/fs.h>
#include <linux/ctype.h>
#include <linux/ioport.h>
#include <linux/kernel.h>

extern unsigned long * prof_buffer;
extern unsigned long prof_len;
extern char edata, end;
extern char *linux_banner;
extern int parse_machine_options(char *line);
extern int root_mountflags;
extern int console_loglevel;

extern struct {
        char *str;
        void (*setup_func)(char *, int *);
} *bootsetups;

/*
 * Boot command-line arguments
 */
void copy_options(char * to, char * from);
void parse_options(char *line);
#define MAX_INIT_ARGS 8
#define MAX_INIT_ENVS 8
#define COMMAND_LINE ((char *) (PARAM+2048))
#define COMMAND_LINE_SIZE 256

extern unsigned long memory_start;		/* After mem_init, stores the */
                                                /* amount of free user memory */
extern unsigned long memory_end;
extern unsigned long low_memory_start;

static char term[21];
int rows, cols;

static char * argv_init[MAX_INIT_ARGS+2] = { "init", NULL, };
static char * envp_init[MAX_INIT_ENVS+2] = { "HOME=/", term, NULL, };

static char * argv_rc[] = { "/bin/sh", NULL };
static char * envp_rc[] = { "HOME=/", term, NULL };

static char * argv[] = { "-/bin/sh",NULL };
static char * envp[] = { "HOME=/usr/root", term, NULL };

/*
 * 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.
 */
#define __NR__exit __NR_exit
static inline _syscall0(int,idle)
static inline _syscall0(int,fork)
static inline _syscall0(int,pause)
static inline _syscall0(int,setup)
static inline _syscall0(int,sync)
static inline _syscall0(pid_t,setsid)
static inline _syscall3(int,write,int,fd,const char *,buf,off_t,count)
static inline _syscall1(int,dup,int,fd)
static inline _syscall3(int,execve,const char *,file,char **,argv,char **,envp)
static inline _syscall3(int,open,const char *,file,int,flag,int,mode)
static inline _syscall1(int,close,int,fd)
static inline _syscall1(int,_exit,int,exitcode)
static inline _syscall3(pid_t,waitpid,pid_t,pid,int *,wait_stat,int,options)

static inline pid_t wait(int * wait_stat)
{
	return waitpid(-1,wait_stat,0);
}

static char printbuf[1024];

char *get_options(char *str, int *ints)
{
	char *cur = str;
	int i=1;

	while (cur && isdigit(*cur) && i <= 10) {
		ints[i++] = simple_strtoul(cur,NULL,0);
		if ((cur = strchr(cur,',')) != NULL)
			cur++;
	}
	ints[0] = i-1;
	return(cur);
}

static int checksetup(char *line)
{
        int i = 0;
        int ints[11];

        while (bootsetups[i].str) {
                int n = strlen(bootsetups[i].str);
                if (!strncmp(line,bootsetups[i].str,n)) {
                        bootsetups[i].setup_func(get_options(line+n,ints), ints);
                        return 1;
                }
                i++;
        }
        return 0;
}

/*
 * This is a simple kernel command line parsing function: it parses
 * the command line, and fills in the arguments/environment to init
 * as appropriate. Any cmd-line option is taken to be an environment
 * variable if it contains the character '='.
 *
 *
 * This routine also checks for options meant for the kernel - currently
 * only the "root=XXXX" option is recognized. These options are not given
 * to init - they are for internal kernel use only.
 */
void parse_options(char *line)
{
	char *next;
	char *devnames[] = { "hda", "hdb", "sda", "sdb", "sdc", "sdd", "sde", "fd", "xda", "xdb", NULL };
	int devnums[]    = { 0x300, 0x340, 0x800, 0x810, 0x820, 0x830, 0x840, 0x200, 0xD00, 0xD40, 0};
	int args, envs;

	if (!*line)
		return;
	args = 0;
	envs = 1;	/* TERM is set to 'console' by default */
	next = line;
	while ((line = next) != NULL) {
		if ((next = strchr(line,' ')) != NULL)
			*next++ = 0;
		/*
		 * check for kernel options first..
		 */
		if (!strncmp(line,"root=",5)) {
			int n;
			line += 5;
			if (strncmp(line,"/dev/",5)) {
				ROOT_DEV = simple_strtoul(line,NULL,16);
				continue;
			}
			line += 5;
			for (n = 0 ; devnames[n] ; n++) {
				int len = strlen(devnames[n]);
				if (!strncmp(line,devnames[n],len)) {
					ROOT_DEV = devnums[n]+simple_strtoul(line+len,NULL,0);
					break;
				}
			}
			continue;
		}
		if (!strcmp(line,"ro")) {
			root_mountflags |= MS_RDONLY;
			continue;
		}
		if (!strcmp(line,"rw")) {
			root_mountflags &= ~MS_RDONLY;
			continue;
		}
		if (!strcmp(line,"debug")) {
			console_loglevel = 10;
			continue;
		}
		if (parse_machine_options(line))
			continue;

		if (checksetup(line))
			continue;
		/*
		 * Then check if it's an environment variable or
		 * an option.
		 */	
		if (strchr(line,'=')) {
			if (envs >= MAX_INIT_ENVS)
				break;
			envp_init[++envs] = line;
		} else {
			if (args >= MAX_INIT_ARGS)
				break;
			argv_init[++args] = line;
		}
	}
	argv_init[args+1] = NULL;
	envp_init[envs+1] = NULL;
}

void copy_options(char * to, char * from)
{
	char c = ' ';
	int len = 0;

	for (;;) {
		if (c == ' ' && *(unsigned long *)from == *(unsigned long *)"mem=")
			memory_end = simple_strtoul(from+4, &from, 0);
		c = *(from++);
		if (!c)
			break;
		if (COMMAND_LINE_SIZE <= ++len)
			break;
		*(to++) = c;
	}
	*to = '\0';
}

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;
}

void init(void)
{
	int pid,i;

	setup();
	sprintf(term, "TERM=con%dx%d", ORIG_VIDEO_COLS, ORIG_VIDEO_LINES);

	#ifdef CONFIG_UMSDOS_FS
	{
		/*
			When mounting a umsdos fs as root, we detect
			the pseudo_root (/linux) and initialise it here.
			pseudo_root is defined in fs/umsdos/inode.c
		*/
		extern struct inode *pseudo_root;
		if (pseudo_root != NULL){
			current->fs->root = pseudo_root;
			current->fs->pwd  = pseudo_root;
		}
	}
	#endif

	(void) open("/dev/tty1",O_RDWR,0);
	(void) dup(0);
	(void) dup(0);

	execve("/etc/init",argv_init,envp_init);
	execve("/bin/init",argv_init,envp_init);
	execve("/sbin/init",argv_init,envp_init);
	/* if this fails, fall through to original stuff */

	if (!(pid=fork())) {
		close(0);
		if (open("/etc/rc",O_RDONLY,0))
			_exit(1);
		execve("/bin/sh",argv_rc,envp_rc);
		_exit(2);
	}
	if (pid>0)
		while (pid != wait(&i))
			/* nothing */;
	while (1) {
		if ((pid = fork()) < 0) {
			printf("Fork failed in init\n\r");
			continue;
		}
		if (!pid) {
			close(0);close(1);close(2);
			setsid();
			(void) open("/dev/tty1",O_RDWR,0);
			(void) dup(0);
			(void) dup(0);
			_exit(execve("/bin/sh",argv,envp));
		}
		while (1)
			if (pid == wait(&i))
				break;
		printf("\n\rchild %d died with code %04x\n\r",pid,i);
		sync();
	}
	_exit(0);
}