/* * linux/init/main.c * * Copyright (C) 1991, 1992 Linus Torvalds */ #include #include #include #include #include #include #include #include #include #include #include #include extern unsigned long * prof_buffer; extern unsigned long prof_len; extern int end; extern char *linux_banner; /* * 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,idle) static inline _syscall0(int,fork) static inline _syscall0(int,pause) static inline _syscall1(int,setup,void *,BIOS) 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 _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]; extern int vsprintf(); extern void init(void); extern void init_IRQ(void); extern long blk_dev_init(long,long); extern long chr_dev_init(long,long); extern void floppy_init(void); extern void sock_init(void); extern long rd_init(long mem_start, int length); extern long kernel_mktime(struct mktime * time); extern unsigned long simple_strtoul(const char *cp,char **endp,unsigned int base); #ifdef CONFIG_SCSI extern unsigned long scsi_dev_init(unsigned long, unsigned long); #endif /* * This is set up by the setup-routine at boot-time */ #define EXT_MEM_K (*(unsigned short *)0x90002) #define DRIVE_INFO (*(struct drive_info *)0x90080) #define SCREEN_INFO (*(struct screen_info *)0x90000) #define ORIG_ROOT_DEV (*(unsigned short *)0x901FC) #define AUX_DEVICE_INFO (*(unsigned char *)0x901FF) /* * Boot command-line arguments */ #define MAX_INIT_ARGS 8 #define MAX_INIT_ENVS 8 #define CL_MAGIC_ADDR (*(unsigned short *) 0x90020) #define CL_MAGIC 0xa33f #define CL_BASE_ADDR ((char *) 0x90000) #define CL_OFFSET (*(unsigned short *) 0x90022) /* * 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 mktime time; do { time.sec = CMOS_READ(0); time.min = CMOS_READ(2); time.hour = CMOS_READ(4); time.day = CMOS_READ(7); time.mon = CMOS_READ(8); time.year = CMOS_READ(9); } while (time.sec != CMOS_READ(0)); BCD_TO_BIN(time.sec); BCD_TO_BIN(time.min); BCD_TO_BIN(time.hour); BCD_TO_BIN(time.day); BCD_TO_BIN(time.mon); BCD_TO_BIN(time.year); time.mon--; startup_time = kernel_mktime(&time); } static unsigned long memory_start = 0; /* After mem_init, stores the */ /* amount of free user memory */ static unsigned long memory_end = 0; static unsigned long low_memory_start = 0; static char * argv_init[MAX_INIT_ARGS+2] = { "/bin/init", NULL, }; static char * envp_init[MAX_INIT_ENVS+2] = { "HOME=/", "TERM=console", NULL, }; static char * argv_rc[] = { "/bin/sh", NULL }; static char * envp_rc[] = { "HOME=/", "TERM=console", NULL }; static char * argv[] = { "-/bin/sh",NULL }; static char * envp[] = { "HOME=/usr/root", "TERM=console", NULL }; struct drive_info { char dummy[32]; } drive_info; struct screen_info screen_info; unsigned char aux_device_present; static char command_line[80] = { 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. */ static void parse_options(char *line) { char *next; int args, envs; if (!*line) return; args = 0; envs = 1; /* TERM is set to 'console' by default */ next = line; while (line = next) { if (next = strchr(line,' ')) *next++ = 0; /* * check for kernel options first.. */ if (!strncmp(line,"root=",5)) { ROOT_DEV = simple_strtoul(line+5,NULL,16); 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 start_kernel(void) { /* * Interrupts are still disabled. Do necessary setups, then * enable them */ ROOT_DEV = ORIG_ROOT_DEV; drive_info = DRIVE_INFO; screen_info = SCREEN_INFO; aux_device_present = AUX_DEVICE_INFO; memory_end = (1<<20) + (EXT_MEM_K<<10); memory_end &= 0xfffff000; #ifdef MAX_16M if (memory_end > 16*1024*1024) memory_end = 16*1024*1024; #endif memory_start = 1024*1024; low_memory_start = (unsigned long) &end; low_memory_start += 0xfff; low_memory_start &= 0xfffff000; memory_start = paging_init(memory_start,memory_end); if (CL_MAGIC_ADDR == CL_MAGIC) strcpy(command_line,CL_BASE_ADDR+CL_OFFSET); trap_init(); init_IRQ(); sched_init(); parse_options(command_line); #ifdef PROFILE_SHIFT prof_buffer = (unsigned long *) memory_start; prof_len = (unsigned long) &end; prof_len >>= PROFILE_SHIFT; memory_start += prof_len * sizeof(unsigned long); #endif memory_start = chr_dev_init(memory_start,memory_end); memory_start = blk_dev_init(memory_start,memory_end); #ifdef CONFIG_SCSI memory_start = scsi_dev_init(memory_start,memory_end); #endif mem_init(low_memory_start,memory_start,memory_end); buffer_init(); inode_init(); time_init(); floppy_init(); sock_init(); sti(); move_to_user_mode(); if (!fork()) /* we count on this going ok */ init(); /* * task[0] is meant to be used as an "idle" task: it may not sleep, but * it might do some general things like count free pages or it could be * used to implement a reasonable LRU algorithm for the paging routines: * anything that can be useful, but shouldn't take time from the real * processes. * * Right now task[0] just does a infinite idle loop. */ for(;;) idle(); } 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((void *) &drive_info); (void) open("/dev/tty1",O_RDWR,0); (void) dup(0); (void) dup(0); printf(linux_banner); execve("/etc/init",argv_init,envp_init); execve("/bin/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\r\n"); 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); /* NOTE! _exit, not exit() */ }