root/init/main.c

/* */

DEFINITIONS

1. get_options
2. profile_setup
3. ramdisk_setup
4. checksetup
5. calibrate_delay
6. parse_options
7. start_secondary
8. smp_idle
9. smp_init
10. smp_begin
11. start_kernel
12. printf
13. do_rc
14. do_shell
15. init

   1 /*
   2  *  linux/init/main.c
   3  *
   4  *  Copyright (C) 1991, 1992  Linus Torvalds
   5  *
   6  *  GK 2/5/95  -  Changed to support mounting root fs via NFS
   7  */
   8 
   9 #define __KERNEL_SYSCALLS__
  10 #include <stdarg.h>
  11 
  12 #include <asm/system.h>
  13 #include <asm/io.h>
  14 
  15 #include <linux/types.h>
  16 #include <linux/fcntl.h>
  17 #include <linux/config.h>
  18 #include <linux/sched.h>
  19 #include <linux/tty.h>
  20 #include <linux/head.h>
  21 #include <linux/unistd.h>
  22 #include <linux/string.h>
  23 #include <linux/timer.h>
  24 #include <linux/fs.h>
  25 #include <linux/ctype.h>
  26 #include <linux/delay.h>
  27 #include <linux/utsname.h>
  28 #include <linux/ioport.h>
  29 #include <linux/hdreg.h>
  30 #include <linux/mm.h>
  31 #include <linux/major.h>
  32 
  33 #include <asm/bugs.h>
  34 
  35 extern char _stext, _etext;
  36 extern char *linux_banner;
  37 
  38 static char printbuf[1024];
  39 
  40 extern int console_loglevel;
  41 
  42 static int init(void *);
  43 
  44 extern void init_IRQ(void);
  45 extern void init_modules(void);
  46 extern long console_init(long, long);
  47 extern long kmalloc_init(long,long);
  48 extern void sock_init(void);
  49 extern long rd_init(long mem_start, int length);
  50 extern long pci_init(long, long);
  51 
  52 extern void swap_setup(char *str, int *ints);
  53 extern void buff_setup(char *str, int *ints);
  54 extern void bmouse_setup(char *str, int *ints);
  55 extern void eth_setup(char *str, int *ints);
  56 extern void xd_setup(char *str, int *ints);
  57 extern void floppy_setup(char *str, int *ints);
  58 extern void st_setup(char *str, int *ints);
  59 extern void st0x_setup(char *str, int *ints);
  60 extern void tmc8xx_setup(char *str, int *ints);
  61 extern void t128_setup(char *str, int *ints);
  62 extern void pas16_setup(char *str, int *ints);
  63 extern void generic_NCR5380_setup(char *str, int *intr);
  64 extern void aha152x_setup(char *str, int *ints);
  65 extern void aha1542_setup(char *str, int *ints);
  66 extern void aic7xxx_setup(char *str, int *ints);
  67 extern void BusLogic_Setup(char *str, int *ints);
  68 extern void fdomain_setup(char *str, int *ints);
  69 extern void NCR53c406a_setup(char *str, int *ints);
  70 extern void scsi_luns_setup(char *str, int *ints);
  71 extern void sound_setup(char *str, int *ints);
  72 #ifdef CONFIG_CDU31A
  73 extern void cdu31a_setup(char *str, int *ints);
  74 #endif CONFIG_CDU31A
  75 #ifdef CONFIG_MCD
  76 extern void mcd_setup(char *str, int *ints);
  77 #endif CONFIG_MCD
  78 #ifdef CONFIG_MCDX
  79 extern void mcdx_setup(char *str, int *ints);
  80 #endif CONFIG_MCDX
  81 #ifdef CONFIG_SBPCD
  82 extern void sbpcd_setup(char *str, int *ints);
  83 #endif CONFIG_SBPCD
  84 #ifdef CONFIG_AZTCD
  85 extern void aztcd_setup(char *str, int *ints);
  86 #endif CONFIG_AZTCD
  87 #ifdef CONFIG_CDU535
  88 extern void sonycd535_setup(char *str, int *ints);
  89 #endif CONFIG_CDU535
  90 #ifdef CONFIG_GSCD
  91 extern void gscd_setup(char *str, int *ints);
  92 #endif CONFIG_GSCD
  93 #ifdef CONFIG_CM206
  94 extern void cm206_setup(char *str, int *ints);
  95 #endif CONFIG_CM206
  96 #ifdef CONFIG_OPTCD
  97 extern void optcd_setup(char *str, int *ints);
  98 #endif CONFIG_OPTCD
  99 #ifdef CONFIG_SJCD
 100 extern void sjcd_setup(char *str, int *ints);
 101 #endif CONFIG_SJCD
 102 static void ramdisk_setup(char *str, int *ints);
 103 
 104 #ifdef CONFIG_SYSVIPC
 105 extern void ipc_init(void);
 106 #endif
 107 
 108 /*
 109  * Boot command-line arguments
 110  */
 111 #define MAX_INIT_ARGS 8
 112 #define MAX_INIT_ENVS 8
 113 
 114 extern void time_init(void);
 115 
 116 static unsigned long memory_start = 0;
 117 static unsigned long memory_end = 0;
 118 
 119 int rows, cols;
 120 
 121 int ramdisk_size;
 122 int root_mountflags = MS_RDONLY;
 123 char *execute_command = 0;
 124 
 125 #ifdef CONFIG_ROOT_NFS
 126 char nfs_root_name[256] = { NFS_ROOT };
 127 char nfs_root_addrs[128] = { "" };
 128 #endif
 129 
 130 static char * argv_init[MAX_INIT_ARGS+2] = { "init", NULL, };
 131 static char * envp_init[MAX_INIT_ENVS+2] = { "HOME=/", "TERM=linux", NULL, };
 132 
 133 static char * argv_rc[] = { "/bin/sh", NULL };
 134 static char * envp_rc[] = { "HOME=/", "TERM=linux", NULL };
 135 
 136 static char * argv[] = { "-/bin/sh",NULL };
 137 static char * envp[] = { "HOME=/usr/root", "TERM=linux", NULL };
 138 
 139 char *get_options(char *str, int *ints)
     /*  */
 140 {
 141         char *cur = str;
 142         int i=1;
 143 
 144         while (cur && isdigit(*cur) && i <= 10) {
 145                 ints[i++] = simple_strtoul(cur,NULL,0);
 146                 if ((cur = strchr(cur,',')) != NULL)
 147                         cur++;
 148         }
 149         ints[0] = i-1;
 150         return(cur);
 151 }
 152 
 153 static void profile_setup(char *str, int *ints)
     /*  */
 154 {
 155         if (ints[0] > 0)
 156                 prof_shift = (unsigned long) ints[1];
 157         else
 158 #ifdef CONFIG_PROFILE_SHIFT
 159                 prof_shift = CONFIG_PROFILE_SHIFT;
 160 #else
 161                 prof_shift = 2;
 162 #endif
 163 }
 164 
 165 struct {
 166         const char *str;
 167         void (*setup_func)(char *, int *);
 168 } bootsetups[] = {
 169         { "reserve=", reserve_setup },
 170         { "profile=", profile_setup },
 171         { "ramdisk=", ramdisk_setup },
 172         { "swap=", swap_setup },
 173         { "buff=", buff_setup },
 174 #ifdef CONFIG_BUGi386
 175         { "no-hlt", no_halt },
 176         { "no387", no_387 },
 177 #endif
 178 #ifdef CONFIG_INET
 179         { "ether=", eth_setup },
 180 #endif
 181 #ifdef CONFIG_SCSI
 182         { "max_scsi_luns=", scsi_luns_setup },
 183 #endif
 184 #if defined(CONFIG_BLK_DEV_HD)
 185         { "hd=", hd_setup },
 186 #endif
 187 #ifdef CONFIG_CHR_DEV_ST
 188         { "st=", st_setup },
 189 #endif
 190 #ifdef CONFIG_BUSMOUSE
 191         { "bmouse=", bmouse_setup },
 192 #endif
 193 #ifdef CONFIG_SCSI_SEAGATE
 194         { "st0x=", st0x_setup },
 195         { "tmc8xx=", tmc8xx_setup },
 196 #endif
 197 #ifdef CONFIG_SCSI_T128
 198         { "t128=", t128_setup },
 199 #endif
 200 #ifdef CONFIG_SCSI_PAS16
 201         { "pas16=", pas16_setup },
 202 #endif
 203 #ifdef CONFIG_SCSI_GENERIC_NCR5380
 204         { "ncr5380=", generic_NCR5380_setup },
 205 #endif
 206 #ifdef CONFIG_SCSI_AHA152X
 207         { "aha152x=", aha152x_setup},
 208 #endif
 209 #ifdef CONFIG_SCSI_AHA1542
 210         { "aha1542=", aha1542_setup},
 211 #endif
 212 #ifdef CONFIG_SCSI_AIC7XXX
 213         { "aic7xxx=", aic7xxx_setup},
 214 #endif
 215 #ifdef CONFIG_SCSI_BUSLOGIC
 216         { "BusLogic=", BusLogic_Setup},
 217 #endif
 218 #ifdef CONFIG_SCSI_NCR53C406A
 219         { "ncr53c406a=", NCR53c406a_setup},
 220 #endif
 221 #ifdef CONFIG_SCSI_FUTURE_DOMAIN
 222         { "fdomain=", fdomain_setup},
 223 #endif
 224 #ifdef CONFIG_BLK_DEV_XD
 225         { "xd=", xd_setup },
 226 #endif
 227 #ifdef CONFIG_BLK_DEV_FD
 228         { "floppy=", floppy_setup },
 229 #endif
 230 #ifdef CONFIG_CDU31A
 231         { "cdu31a=", cdu31a_setup },
 232 #endif CONFIG_CDU31A
 233 #ifdef CONFIG_MCD
 234         { "mcd=", mcd_setup },
 235 #endif CONFIG_MCD
 236 #ifdef CONFIG_MCDX
 237         { "mcdx=", mcdx_setup },
 238 #endif CONFIG_MCDX
 239 #ifdef CONFIG_SBPCD
 240         { "sbpcd=", sbpcd_setup },
 241 #endif CONFIG_SBPCD
 242 #ifdef CONFIG_AZTCD
 243         { "aztcd=", aztcd_setup },
 244 #endif CONFIG_AZTCD
 245 #ifdef CONFIG_CDU535
 246         { "sonycd535=", sonycd535_setup },
 247 #endif CONFIG_CDU535
 248 #ifdef CONFIG_GSCD
 249         { "gscd=", gscd_setup },
 250 #endif CONFIG_GSCD
 251 #ifdef CONFIG_CM206
 252         { "cm206=", cm206_setup },
 253 #endif CONFIG_CM206
 254 #ifdef CONFIG_OPTCD
 255         { "optcd=", optcd_setup },
 256 #endif CONFIG_OPTCD
 257 #ifdef CONFIG_SJCD
 258         { "sjcd=", sjcd_setup },
 259 #endif CONFIG_SJCD
 260 #ifdef CONFIG_SOUND
 261         { "sound=", sound_setup },
 262 #endif
 263         { 0, 0 }
 264 };
 265 
 266 static void ramdisk_setup(char *str, int *ints)
     /*  */
 267 {
 268    if (ints[0] > 0 && ints[1] >= 0)
 269       ramdisk_size = ints[1];
 270 }
 271 
 272 static int checksetup(char *line)
     /*  */
 273 {
 274         int i = 0;
 275         int ints[11];
 276 
 277 #ifdef CONFIG_BLK_DEV_IDE
 278         /* ide driver needs the basic string, rather than pre-processed values */
 279         if (!strncmp(line,"ide",3) || (!strncmp(line,"hd",2) && line[2] != '=')) {
 280                 ide_setup(line);
 281                 return 1;
 282         }
 283 #endif
 284         while (bootsetups[i].str) {
 285                 int n = strlen(bootsetups[i].str);
 286                 if (!strncmp(line,bootsetups[i].str,n)) {
 287                         bootsetups[i].setup_func(get_options(line+n,ints), ints);
 288                         return 1;
 289                 }
 290                 i++;
 291         }
 292         return 0;
 293 }
 294 
 295 /* this should be approx 2 Bo*oMips to start (note initial shift), and will
 296    still work even if initally too large, it will just take slightly longer */
 297 unsigned long loops_per_sec = (1<<12);
 298 
 299 /* This is the number of bits of precision for the loops_per_second.  Each
 300    bit takes on average 1.5/HZ seconds.  This (like the original) is a little
 301    better than 1% */
 302 #define LPS_PREC 8
 303 
 304 void calibrate_delay(void)
     /*  */
 305 {
 306         int ticks;
 307         int loopbit;
 308         int lps_precision = LPS_PREC;
 309 
 310         loops_per_sec = (1<<12);
 311 
 312         printk("Calibrating delay loop.. ");
 313         while (loops_per_sec <<= 1) {
 314                 /* wait for "start of" clock tick */
 315                 ticks = jiffies;
 316                 while (ticks == jiffies)
 317                         /* nothing */;
 318                 /* Go .. */
 319                 ticks = jiffies;
 320                 __delay(loops_per_sec);
 321                 ticks = jiffies - ticks;
 322                 if (ticks)
 323                         break;
 324                 }
 325 
 326 /* Do a binary approximation to get loops_per_second set to equal one clock
 327    (up to lps_precision bits) */
 328         loops_per_sec >>= 1;
 329         loopbit = loops_per_sec;
 330         while ( lps_precision-- && (loopbit >>= 1) ) {
 331                 loops_per_sec |= loopbit;
 332                 ticks = jiffies;
 333                 while (ticks == jiffies);
 334                 ticks = jiffies;
 335                 __delay(loops_per_sec);
 336                 if (jiffies != ticks)   /* longer than 1 tick */
 337                         loops_per_sec &= ~loopbit;
 338         }
 339 
 340 /* finally, adjust loops per second in terms of seconds instead of clocks */    
 341         loops_per_sec *= HZ;
 342 /* Round the value and print it */      
 343         printk("ok - %lu.%02lu BogoMIPS\n",
 344                 (loops_per_sec+2500)/500000,
 345                 ((loops_per_sec+2500)/5000) % 100);
 346 }
 347 
 348 /*
 349  * This is a simple kernel command line parsing function: it parses
 350  * the command line, and fills in the arguments/environment to init
 351  * as appropriate. Any cmd-line option is taken to be an environment
 352  * variable if it contains the character '='.
 353  *
 354  *
 355  * This routine also checks for options meant for the kernel.
 356  * These options are not given to init - they are for internal kernel use only.
 357  */
 358 static void parse_options(char *line)
     /*  */
 359 {
 360         char *next;
 361 #ifdef CONFIG_ROOT_NFS
 362         char *devnames[] = { "nfs", "hda", "hdb", "hdc", "hdd", "sda", "sdb", "sdc", "sdd", "sde", "fd", "xda", "xdb", NULL };
 363         int devnums[]    = { 0x0FF, 0x300, 0x340, 0x1600, 0x1640, 0x800, 0x810, 0x820, 0x830, 0x840, 0x200, 0xD00, 0xD40, 0};
 364 #else
 365         static const char *devnames[] = { "hda", "hdb", "hdc", "hdd", "sda", "sdb", "sdc", "sdd", "sde", "fd", "xda", "xdb", NULL };
 366         static int devnums[]    = { 0x300, 0x340, 0x1600, 0x1640, 0x800, 0x810, 0x820, 0x830, 0x840, 0x200, 0xD00, 0xD40, 0};
 367 #endif
 368         int args, envs;
 369         if (!*line)
 370                 return;
 371         args = 0;
 372         envs = 1;       /* TERM is set to 'linux' by default */
 373         next = line;
 374         while ((line = next) != NULL) {
 375                 if ((next = strchr(line,' ')) != NULL)
 376                         *next++ = 0;
 377                 /*
 378                  * check for kernel options first..
 379                  */
 380                 if (!strncmp(line,"root=",5)) {
 381                         int n;
 382                         line += 5;
 383                         if (strncmp(line,"/dev/",5)) {
 384                                 ROOT_DEV = to_kdev_t(
 385                                              simple_strtoul(line,NULL,16));
 386                                 continue;
 387                         }
 388                         line += 5;
 389                         for (n = 0 ; devnames[n] ; n++) {
 390                                 int len = strlen(devnames[n]);
 391                                 if (!strncmp(line,devnames[n],len)) {
 392                                         ROOT_DEV = to_kdev_t(devnums[n]+
 393                                              simple_strtoul(line+len,NULL,0));
 394                                         break;
 395                                 }
 396                         }
 397                         continue;
 398                 }
 399 #ifdef CONFIG_ROOT_NFS
 400                 if (!strncmp(line, "nfsroot=", 8)) {
 401                         int n;
 402                         line += 8;
 403                         if (line[0] == '/' || (line[0] >= '0' && line[0] <= '9')) {
 404                                 strncpy(nfs_root_name, line, sizeof(nfs_root_name));
 405                                 nfs_root_name[sizeof(nfs_root_name)] = '\0';
 406                                 continue;
 407                         }
 408                         n = strlen(line) + strlen(NFS_ROOT);
 409                         if (n >= sizeof(nfs_root_name))
 410                                 line[sizeof(nfs_root_name) - strlen(NFS_ROOT) - 1] = '\0';
 411                         sprintf(nfs_root_name, NFS_ROOT, line);
 412                         continue;
 413                 }
 414                 if (!strncmp(line, "nfsaddrs=", 9)) {
 415                         line += 9;
 416                         strncpy(nfs_root_addrs, line, sizeof(nfs_root_addrs));
 417                         nfs_root_addrs[sizeof(nfs_root_addrs)] = '\0';
 418                         continue;
 419                 }
 420 #endif
 421                 if (!strcmp(line,"ro")) {
 422                         root_mountflags |= MS_RDONLY;
 423                         continue;
 424                 }
 425                 if (!strcmp(line,"rw")) {
 426                         root_mountflags &= ~MS_RDONLY;
 427                         continue;
 428                 }
 429                 if (!strcmp(line,"debug")) {
 430                         console_loglevel = 10;
 431                         continue;
 432                 }
 433                 if (!strncmp(line,"init=",5)) {
 434                         line += 5;
 435                         execute_command = line;
 436                         continue;
 437                 }
 438                 if (checksetup(line))
 439                         continue;
 440                 /*
 441                  * Then check if it's an environment variable or
 442                  * an option.
 443                  */
 444                 if (strchr(line,'=')) {
 445                         if (envs >= MAX_INIT_ENVS)
 446                                 break;
 447                         envp_init[++envs] = line;
 448                 } else {
 449                         if (args >= MAX_INIT_ARGS)
 450                                 break;
 451                         argv_init[++args] = line;
 452                 }
 453         }
 454         argv_init[args+1] = NULL;
 455         envp_init[envs+1] = NULL;
 456 }
 457 
 458 extern void setup_arch(char **, unsigned long *, unsigned long *);
 459 
 460 #ifdef __SMP__
 461 /*
 462  *      Activate a secondary processor.
 463  */
 464  
 465 asmlinkage void start_secondary(void)
     /*  */
 466 {
 467         trap_init();
 468         init_IRQ();
 469         smp_callin();
 470         for(;;)
 471                 idle();
 472 }
 473 
 474 int smp_idle(void * unused)
     /*  */
 475 {
 476         for (;;)
 477                 idle();
 478 }
 479 
 480 /*
 481  *      Called by CPU#0 to activate the rest.
 482  */
 483  
 484 static void smp_init(void)
     /*  */
 485 {
 486         int i=0;
 487         smp_boot_cpus();
 488         
 489         /*
 490          *      Create the slave init tasks as sharing pid 0.
 491          */
 492 
 493         for(i=1;i<smp_num_cpus;i++)
 494         {
 495                 kernel_thread(smp_idle, NULL, CLONE_PID);
 496                 /*
 497                  *      Assume linear processor numbering
 498                  */
 499                 current_set[i]=task[i];
 500                 current_set[i]->processor=i;
 501         }
 502 }               
 503 
 504 /*
 505  *      The autoprobe routines assume CPU#0 on the i386
 506  *      so we don't actually set the game in motion until
 507  *      they are finished.
 508  */
 509  
 510 static void smp_begin(void)
     /*  */
 511 {
 512         smp_threads_ready=1;
 513         smp_commence();
 514 }
 515         
 516 #endif
 517 
 518 /*
 519  *      Activate the first processor.
 520  */
 521  
 522 asmlinkage void start_kernel(void)
     /*  */
 523 {
 524         char * command_line;
 525 
 526 /*
 527  *      This little check will move.
 528  */
 529 
 530 #ifdef __SMP__
 531         static int first_cpu=1;
 532         
 533         if(!first_cpu)
 534                 start_secondary();
 535         first_cpu=0;
 536         
 537 #endif  
 538 /*
 539  * Interrupts are still disabled. Do necessary setups, then
 540  * enable them
 541  */
 542         setup_arch(&command_line, &memory_start, &memory_end);
 543         memory_start = paging_init(memory_start,memory_end);
 544         trap_init();
 545         init_IRQ();
 546         sched_init();
 547         time_init();
 548         parse_options(command_line);
 549         init_modules();
 550 #ifdef CONFIG_PROFILE
 551         if (!prof_shift)
 552 #ifdef CONFIG_PROFILE_SHIFT
 553                 prof_shift = CONFIG_PROFILE_SHIFT;
 554 #else
 555                 prof_shift = 2;
 556 #endif
 557 #endif
 558         if (prof_shift) {
 559                 prof_buffer = (unsigned long *) memory_start;
 560                 /* only text is profiled */
 561                 prof_len = (unsigned long) &_etext - (unsigned long) &_stext;
 562                 prof_len >>= prof_shift;
 563                 memory_start += prof_len * sizeof(unsigned long);
 564         }
 565         memory_start = console_init(memory_start,memory_end);
 566 #ifdef CONFIG_PCI
 567         memory_start = pci_init(memory_start,memory_end);
 568 #endif
 569         memory_start = kmalloc_init(memory_start,memory_end);
 570         sti();
 571         calibrate_delay();
 572         memory_start = inode_init(memory_start,memory_end);
 573         memory_start = file_table_init(memory_start,memory_end);
 574         memory_start = name_cache_init(memory_start,memory_end);
 575         if (ramdisk_size)
 576                 memory_start += rd_init(memory_start, ramdisk_size*1024);
 577         mem_init(memory_start,memory_end);
 578         buffer_init();
 579         sock_init();
 580 #ifdef CONFIG_SYSVIPC
 581         ipc_init();
 582 #endif
 583         sti();
 584         check_bugs();
 585 
 586         printk(linux_banner);
 587 #ifdef __SMP__
 588         smp_init();
 589 #endif
 590         /* we count on the initial thread going ok */
 591         kernel_thread(init, NULL, 0);
 592 /*
 593  * task[0] is meant to be used as an "idle" task: it may not sleep, but
 594  * it might do some general things like count free pages or it could be
 595  * used to implement a reasonable LRU algorithm for the paging routines:
 596  * anything that can be useful, but shouldn't take time from the real
 597  * processes.
 598  *
 599  * Right now task[0] just does a infinite idle loop.
 600  */
 601         for(;;)
 602                 idle();
 603 }
 604 
 605 static int printf(const char *fmt, ...)
     /*  */
 606 {
 607         va_list args;
 608         int i;
 609 
 610         va_start(args, fmt);
 611         write(1,printbuf,i=vsprintf(printbuf, fmt, args));
 612         va_end(args);
 613         return i;
 614 }
 615 
 616 static int do_rc(void * rc)
     /*  */
 617 {
 618         close(0);
 619         if (open(rc,O_RDONLY,0))
 620                 return -1;
 621         return execve("/bin/sh", argv_rc, envp_rc);
 622 }
 623 
 624 static int do_shell(void * shell)
     /*  */
 625 {
 626         close(0);close(1);close(2);
 627         setsid();
 628         (void) open("/dev/tty1",O_RDWR,0);
 629         (void) dup(0);
 630         (void) dup(0);
 631         return execve(shell, argv, envp);
 632 }
 633 
 634 static int init(void * unused)
     /*  */
 635 {
 636         int pid,i;
 637 
 638         setup();
 639 
 640 #ifdef __SMP__
 641         /*
 642          *      With the devices probed and setup we can
 643          *      now enter SMP mode.
 644          */
 645         
 646         smp_begin();
 647 #endif  
 648 
 649         #ifdef CONFIG_UMSDOS_FS
 650         {
 651                 /*
 652                         When mounting a umsdos fs as root, we detect
 653                         the pseudo_root (/linux) and initialise it here.
 654                         pseudo_root is defined in fs/umsdos/inode.c
 655                 */
 656                 extern struct inode *pseudo_root;
 657                 if (pseudo_root != NULL){
 658                         current->fs->root = pseudo_root;
 659                         current->fs->pwd  = pseudo_root;
 660                 }
 661         }
 662         #endif
 663 
 664         (void) open("/dev/tty1",O_RDWR,0);
 665         (void) dup(0);
 666         (void) dup(0);
 667 
 668         if (!execute_command) {
 669                 execve("/etc/init",argv_init,envp_init);
 670                 execve("/bin/init",argv_init,envp_init);
 671                 execve("/sbin/init",argv_init,envp_init);
 672                 /* if this fails, fall through to original stuff */
 673 
 674                 pid = kernel_thread(do_rc, "/etc/rc", SIGCHLD);
 675                 if (pid>0)
 676                         while (pid != wait(&i))
 677                                 /* nothing */;
 678                 }
 679 
 680         while (1) {
 681                 pid = kernel_thread(do_shell,
 682                         execute_command ? execute_command : "/bin/sh",
 683                         SIGCHLD);
 684                 if (pid < 0) {
 685                         printf("Fork failed in init\n\r");
 686                         continue;
 687                 }
 688                 while (1)
 689                         if (pid == wait(&i))
 690                                 break;
 691                 printf("\n\rchild %d died with code %04x\n\r",pid,i);
 692                 sync();
 693         }
 694         return -1;
 695 }

/* */