root/init/main.c

/* */

DEFINITIONS

1. get_options
2. profile_setup
3. ramdisk_start_setup
4. load_ramdisk
5. prompt_ramdisk
6. checksetup
7. calibrate_delay
8. parse_options
9. cpu_idle
10. start_secondary
11. smp_init
12. smp_begin
13. start_kernel
14. printf
15. do_rc
16. do_shell
17. 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 #ifdef CONFIG_APM
  33 #include <linux/apm_bios.h>
  34 #endif
  35 
  36 #include <asm/bugs.h>
  37 
  38 extern char _stext, _etext;
  39 extern char *linux_banner;
  40 
  41 static char printbuf[1024];
  42 
  43 extern int console_loglevel;
  44 
  45 static int init(void *);
  46 extern int bdflush(void *);
  47 extern int kswapd(void *);
  48 
  49 extern void init_IRQ(void);
  50 extern void init_modules(void);
  51 extern long console_init(long, long);
  52 extern long kmalloc_init(long,long);
  53 extern void sock_init(void);
  54 extern long pci_init(long, long);
  55 extern void sysctl_init(void);
  56 
  57 extern void swap_setup(char *str, int *ints);
  58 extern void buff_setup(char *str, int *ints);
  59 extern void bmouse_setup(char *str, int *ints);
  60 extern void eth_setup(char *str, int *ints);
  61 extern void xd_setup(char *str, int *ints);
  62 extern void floppy_setup(char *str, int *ints);
  63 extern void st_setup(char *str, int *ints);
  64 extern void st0x_setup(char *str, int *ints);
  65 extern void advansys_setup(char *str, int *ints);
  66 extern void tmc8xx_setup(char *str, int *ints);
  67 extern void t128_setup(char *str, int *ints);
  68 extern void pas16_setup(char *str, int *ints);
  69 extern void generic_NCR5380_setup(char *str, int *intr);
  70 extern void generic_NCR53C400_setup(char *str, int *intr);
  71 extern void aha152x_setup(char *str, int *ints);
  72 extern void aha1542_setup(char *str, int *ints);
  73 extern void aic7xxx_setup(char *str, int *ints);
  74 extern void AM53C974_setup(char *str, int *ints);
  75 extern void BusLogic_Setup(char *str, int *ints);
  76 extern void fdomain_setup(char *str, int *ints);
  77 extern void NCR53c406a_setup(char *str, int *ints);
  78 extern void scsi_luns_setup(char *str, int *ints);
  79 extern void sound_setup(char *str, int *ints);
  80 #ifdef CONFIG_CDU31A
  81 extern void cdu31a_setup(char *str, int *ints);
  82 #endif CONFIG_CDU31A
  83 #ifdef CONFIG_MCD
  84 extern void mcd_setup(char *str, int *ints);
  85 #endif CONFIG_MCD
  86 #ifdef CONFIG_MCDX
  87 extern void mcdx_setup(char *str, int *ints);
  88 #endif CONFIG_MCDX
  89 #ifdef CONFIG_SBPCD
  90 extern void sbpcd_setup(char *str, int *ints);
  91 #endif CONFIG_SBPCD
  92 #ifdef CONFIG_AZTCD
  93 extern void aztcd_setup(char *str, int *ints);
  94 #endif CONFIG_AZTCD
  95 #ifdef CONFIG_CDU535
  96 extern void sonycd535_setup(char *str, int *ints);
  97 #endif CONFIG_CDU535
  98 #ifdef CONFIG_GSCD
  99 extern void gscd_setup(char *str, int *ints);
 100 #endif CONFIG_GSCD
 101 #ifdef CONFIG_CM206
 102 extern void cm206_setup(char *str, int *ints);
 103 #endif CONFIG_CM206
 104 #ifdef CONFIG_OPTCD
 105 extern void optcd_setup(char *str, int *ints);
 106 #endif CONFIG_OPTCD
 107 #ifdef CONFIG_SJCD
 108 extern void sjcd_setup(char *str, int *ints);
 109 #endif CONFIG_SJCD
 110 #ifdef CONFIG_BLK_DEV_RAM
 111 static void ramdisk_start_setup(char *str, int *ints);
 112 static void load_ramdisk(char *str, int *ints);
 113 static void prompt_ramdisk(char *str, int *ints);
 114 #endif CONFIG_BLK_DEV_RAM
 115 
 116 #if defined(CONFIG_SYSVIPC) || defined(CONFIG_KERNELD)
 117 extern void ipc_init(void);
 118 #endif
 119 
 120 /*
 121  * Boot command-line arguments
 122  */
 123 #define MAX_INIT_ARGS 8
 124 #define MAX_INIT_ENVS 8
 125 
 126 extern void time_init(void);
 127 
 128 static unsigned long memory_start = 0;
 129 static unsigned long memory_end = 0;
 130 
 131 int rows, cols;
 132 
 133 #ifdef CONFIG_BLK_DEV_RAM
 134 extern int rd_doload;           /* 1 = load ramdisk, 0 = don't load */
 135 extern int rd_prompt;           /* 1 = prompt for ramdisk, 0 = don't prompt */
 136 extern int rd_image_start;      /* starting block # of image */
 137 #endif
 138 
 139 int root_mountflags = MS_RDONLY;
 140 char *execute_command = 0;
 141 
 142 #ifdef CONFIG_ROOT_NFS
 143 char nfs_root_name[256] = { NFS_ROOT };
 144 char nfs_root_addrs[128] = { "" };
 145 #endif
 146 
 147 extern void dquot_init(void);
 148 
 149 static char * argv_init[MAX_INIT_ARGS+2] = { "init", NULL, };
 150 static char * envp_init[MAX_INIT_ENVS+2] = { "HOME=/", "TERM=linux", NULL, };
 151 
 152 static char * argv_rc[] = { "/bin/sh", NULL };
 153 static char * envp_rc[] = { "HOME=/", "TERM=linux", NULL };
 154 
 155 static char * argv[] = { "-/bin/sh",NULL };
 156 static char * envp[] = { "HOME=/usr/root", "TERM=linux", NULL };
 157 
 158 char *get_options(char *str, int *ints)
     /*  */
 159 {
 160         char *cur = str;
 161         int i=1;
 162 
 163         while (cur && isdigit(*cur) && i <= 10) {
 164                 ints[i++] = simple_strtoul(cur,NULL,0);
 165                 if ((cur = strchr(cur,',')) != NULL)
 166                         cur++;
 167         }
 168         ints[0] = i-1;
 169         return(cur);
 170 }
 171 
 172 static void profile_setup(char *str, int *ints)
     /*  */
 173 {
 174         if (ints[0] > 0)
 175                 prof_shift = (unsigned long) ints[1];
 176         else
 177 #ifdef CONFIG_PROFILE_SHIFT
 178                 prof_shift = CONFIG_PROFILE_SHIFT;
 179 #else
 180                 prof_shift = 2;
 181 #endif
 182 }
 183 
 184 struct {
 185         const char *str;
 186         void (*setup_func)(char *, int *);
 187 } bootsetups[] = {
 188         { "reserve=", reserve_setup },
 189         { "profile=", profile_setup },
 190 #ifdef CONFIG_BLK_DEV_RAM
 191         { "ramdisk_start=", ramdisk_start_setup },
 192         { "load_ramdisk=", load_ramdisk },
 193         { "prompt_ramdisk=", prompt_ramdisk },
 194 #endif
 195         { "swap=", swap_setup },
 196         { "buff=", buff_setup },
 197 #ifdef CONFIG_BUGi386
 198         { "no-hlt", no_halt },
 199         { "no387", no_387 },
 200 #endif
 201 #ifdef CONFIG_INET
 202         { "ether=", eth_setup },
 203 #endif
 204 #ifdef CONFIG_SCSI
 205         { "max_scsi_luns=", scsi_luns_setup },
 206 #endif
 207 #ifdef CONFIG_SCSI_ADVANSYS
 208         { "advansys=", advansys_setup },
 209 #endif
 210 #if defined(CONFIG_BLK_DEV_HD)
 211         { "hd=", hd_setup },
 212 #endif
 213 #ifdef CONFIG_CHR_DEV_ST
 214         { "st=", st_setup },
 215 #endif
 216 #ifdef CONFIG_BUSMOUSE
 217         { "bmouse=", bmouse_setup },
 218 #endif
 219 #ifdef CONFIG_SCSI_SEAGATE
 220         { "st0x=", st0x_setup },
 221         { "tmc8xx=", tmc8xx_setup },
 222 #endif
 223 #ifdef CONFIG_SCSI_T128
 224         { "t128=", t128_setup },
 225 #endif
 226 #ifdef CONFIG_SCSI_PAS16
 227         { "pas16=", pas16_setup },
 228 #endif
 229 #ifdef CONFIG_SCSI_GENERIC_NCR5380
 230         { "ncr5380=", generic_NCR5380_setup },
 231         { "ncr53c400=", generic_NCR53C400_setup },
 232 #endif
 233 #ifdef CONFIG_SCSI_AHA152X
 234         { "aha152x=", aha152x_setup},
 235 #endif
 236 #ifdef CONFIG_SCSI_AHA1542
 237         { "aha1542=", aha1542_setup},
 238 #endif
 239 #ifdef CONFIG_SCSI_AIC7XXX
 240         { "aic7xxx=", aic7xxx_setup},
 241 #endif
 242 #ifdef CONFIG_SCSI_BUSLOGIC
 243         { "BusLogic=", BusLogic_Setup},
 244 #endif
 245 #ifdef CONFIG_SCSI_AM53C974
 246         { "AM53C974=", AM53C974_setup},
 247 #endif
 248 #ifdef CONFIG_SCSI_NCR53C406A
 249         { "ncr53c406a=", NCR53c406a_setup},
 250 #endif
 251 #ifdef CONFIG_SCSI_FUTURE_DOMAIN
 252         { "fdomain=", fdomain_setup},
 253 #endif
 254 #ifdef CONFIG_BLK_DEV_XD
 255         { "xd=", xd_setup },
 256 #endif
 257 #ifdef CONFIG_BLK_DEV_FD
 258         { "floppy=", floppy_setup },
 259 #endif
 260 #ifdef CONFIG_CDU31A
 261         { "cdu31a=", cdu31a_setup },
 262 #endif CONFIG_CDU31A
 263 #ifdef CONFIG_MCD
 264         { "mcd=", mcd_setup },
 265 #endif CONFIG_MCD
 266 #ifdef CONFIG_MCDX
 267         { "mcdx=", mcdx_setup },
 268 #endif CONFIG_MCDX
 269 #ifdef CONFIG_SBPCD
 270         { "sbpcd=", sbpcd_setup },
 271 #endif CONFIG_SBPCD
 272 #ifdef CONFIG_AZTCD
 273         { "aztcd=", aztcd_setup },
 274 #endif CONFIG_AZTCD
 275 #ifdef CONFIG_CDU535
 276         { "sonycd535=", sonycd535_setup },
 277 #endif CONFIG_CDU535
 278 #ifdef CONFIG_GSCD
 279         { "gscd=", gscd_setup },
 280 #endif CONFIG_GSCD
 281 #ifdef CONFIG_CM206
 282         { "cm206=", cm206_setup },
 283 #endif CONFIG_CM206
 284 #ifdef CONFIG_OPTCD
 285         { "optcd=", optcd_setup },
 286 #endif CONFIG_OPTCD
 287 #ifdef CONFIG_SJCD
 288         { "sjcd=", sjcd_setup },
 289 #endif CONFIG_SJCD
 290 #ifdef CONFIG_SOUND
 291         { "sound=", sound_setup },
 292 #endif
 293         { 0, 0 }
 294 };
 295 
 296 #ifdef CONFIG_BLK_DEV_RAM
 297 static void ramdisk_start_setup(char *str, int *ints)
     /*  */
 298 {
 299    if (ints[0] > 0 && ints[1] >= 0)
 300       rd_image_start = ints[1];
 301 }
 302 
 303 static void load_ramdisk(char *str, int *ints)
     /*  */
 304 {
 305    if (ints[0] > 0 && ints[1] >= 0)
 306       rd_doload = ints[1] & 1;
 307 }
 308 
 309 static void prompt_ramdisk(char *str, int *ints)
     /*  */
 310 {
 311    if (ints[0] > 0 && ints[1] >= 0)
 312       rd_prompt = ints[1] & 1;
 313 }
 314 #endif
 315 
 316 static int checksetup(char *line)
     /*  */
 317 {
 318         int i = 0;
 319         int ints[11];
 320 
 321 #ifdef CONFIG_BLK_DEV_IDE
 322         /* ide driver needs the basic string, rather than pre-processed values */
 323         if (!strncmp(line,"ide",3) || (!strncmp(line,"hd",2) && line[2] != '=')) {
 324                 ide_setup(line);
 325                 return 1;
 326         }
 327 #endif
 328         while (bootsetups[i].str) {
 329                 int n = strlen(bootsetups[i].str);
 330                 if (!strncmp(line,bootsetups[i].str,n)) {
 331                         bootsetups[i].setup_func(get_options(line+n,ints), ints);
 332                         return 1;
 333                 }
 334                 i++;
 335         }
 336         return 0;
 337 }
 338 
 339 /* this should be approx 2 Bo*oMips to start (note initial shift), and will
 340    still work even if initally too large, it will just take slightly longer */
 341 unsigned long loops_per_sec = (1<<12);
 342 
 343 /* This is the number of bits of precision for the loops_per_second.  Each
 344    bit takes on average 1.5/HZ seconds.  This (like the original) is a little
 345    better than 1% */
 346 #define LPS_PREC 8
 347 
 348 void calibrate_delay(void)
     /*  */
 349 {
 350         int ticks;
 351         int loopbit;
 352         int lps_precision = LPS_PREC;
 353 
 354         loops_per_sec = (1<<12);
 355 
 356         printk("Calibrating delay loop.. ");
 357         while (loops_per_sec <<= 1) {
 358                 /* wait for "start of" clock tick */
 359                 ticks = jiffies;
 360                 while (ticks == jiffies)
 361                         /* nothing */;
 362                 /* Go .. */
 363                 ticks = jiffies;
 364                 __delay(loops_per_sec);
 365                 ticks = jiffies - ticks;
 366                 if (ticks)
 367                         break;
 368                 }
 369 
 370 /* Do a binary approximation to get loops_per_second set to equal one clock
 371    (up to lps_precision bits) */
 372         loops_per_sec >>= 1;
 373         loopbit = loops_per_sec;
 374         while ( lps_precision-- && (loopbit >>= 1) ) {
 375                 loops_per_sec |= loopbit;
 376                 ticks = jiffies;
 377                 while (ticks == jiffies);
 378                 ticks = jiffies;
 379                 __delay(loops_per_sec);
 380                 if (jiffies != ticks)   /* longer than 1 tick */
 381                         loops_per_sec &= ~loopbit;
 382         }
 383 
 384 /* finally, adjust loops per second in terms of seconds instead of clocks */    
 385         loops_per_sec *= HZ;
 386 /* Round the value and print it */      
 387         printk("ok - %lu.%02lu BogoMIPS\n",
 388                 (loops_per_sec+2500)/500000,
 389                 ((loops_per_sec+2500)/5000) % 100);
 390 }
 391 
 392 /*
 393  * This is a simple kernel command line parsing function: it parses
 394  * the command line, and fills in the arguments/environment to init
 395  * as appropriate. Any cmd-line option is taken to be an environment
 396  * variable if it contains the character '='.
 397  *
 398  *
 399  * This routine also checks for options meant for the kernel.
 400  * These options are not given to init - they are for internal kernel use only.
 401  */
 402 static void parse_options(char *line)
     /*  */
 403 {
 404         char *next;
 405         char *devnames[] = { "nfs", "hda", "hdb", "hdc", "hdd", "sda", "sdb",
 406                 "sdc", "sdd", "sde", "fd", "xda", "xdb", NULL };
 407         int devnums[]    = { 0x0FF, 0x300, 0x340, 0x1600, 0x1640, 0x800,
 408                 0x810, 0x820, 0x830, 0x840, 0x200, 0xD00, 0xD40, 0};
 409         int args, envs;
 410         if (!*line)
 411                 return;
 412         args = 0;
 413         envs = 1;       /* TERM is set to 'linux' by default */
 414         next = line;
 415         while ((line = next) != NULL) {
 416                 if ((next = strchr(line,' ')) != NULL)
 417                         *next++ = 0;
 418                 /*
 419                  * check for kernel options first..
 420                  */
 421                 if (!strncmp(line,"root=",5)) {
 422                         int n;
 423                         line += 5;
 424                         if (strncmp(line,"/dev/",5)) {
 425                                 ROOT_DEV = to_kdev_t(
 426                                              simple_strtoul(line,NULL,16));
 427                                 continue;
 428                         }
 429                         line += 5;
 430                         for (n = 0 ; devnames[n] ; n++) {
 431                                 int len = strlen(devnames[n]);
 432                                 if (!strncmp(line,devnames[n],len)) {
 433                                         ROOT_DEV = to_kdev_t(devnums[n]+
 434                                              simple_strtoul(line+len,NULL,0));
 435                                         break;
 436                                 }
 437                         }
 438                         continue;
 439                 }
 440 #ifdef CONFIG_ROOT_NFS
 441                 if (!strncmp(line, "nfsroot=", 8)) {
 442                         int n;
 443                         line += 8;
 444                         ROOT_DEV = MKDEV(UNNAMED_MAJOR, 255);
 445                         if (line[0] == '/' || (line[0] >= '0' && line[0] <= '9')) {
 446                                 strncpy(nfs_root_name, line, sizeof(nfs_root_name));
 447                                 nfs_root_name[sizeof(nfs_root_name)-1] = '\0';
 448                                 continue;
 449                         }
 450                         n = strlen(line) + strlen(NFS_ROOT);
 451                         if (n >= sizeof(nfs_root_name))
 452                                 line[sizeof(nfs_root_name) - strlen(NFS_ROOT) - 1] = '\0';
 453                         sprintf(nfs_root_name, NFS_ROOT, line);
 454                         continue;
 455                 }
 456                 if (!strncmp(line, "nfsaddrs=", 9)) {
 457                         line += 9;
 458                         strncpy(nfs_root_addrs, line, sizeof(nfs_root_addrs));
 459                         nfs_root_addrs[sizeof(nfs_root_addrs)] = '\0';
 460                         continue;
 461                 }
 462 #endif
 463                 if (!strcmp(line,"ro")) {
 464                         root_mountflags |= MS_RDONLY;
 465                         continue;
 466                 }
 467                 if (!strcmp(line,"rw")) {
 468                         root_mountflags &= ~MS_RDONLY;
 469                         continue;
 470                 }
 471                 if (!strcmp(line,"debug")) {
 472                         console_loglevel = 10;
 473                         continue;
 474                 }
 475                 if (!strncmp(line,"init=",5)) {
 476                         line += 5;
 477                         execute_command = line;
 478                         continue;
 479                 }
 480                 if (checksetup(line))
 481                         continue;
 482                 /*
 483                  * Then check if it's an environment variable or
 484                  * an option.
 485                  */
 486                 if (strchr(line,'=')) {
 487                         if (envs >= MAX_INIT_ENVS)
 488                                 break;
 489                         envp_init[++envs] = line;
 490                 } else {
 491                         if (args >= MAX_INIT_ARGS)
 492                                 break;
 493                         argv_init[++args] = line;
 494                 }
 495         }
 496         argv_init[args+1] = NULL;
 497         envp_init[envs+1] = NULL;
 498 }
 499 
 500 
 501 extern void setup_arch(char **, unsigned long *, unsigned long *);
 502 extern void arch_syms_export(void);
 503 
 504 #ifndef __SMP__
 505 
 506 /*
 507  *      Uniprocessor idle thread
 508  */
 509  
 510 int cpu_idle(void *unused)
     /*  */
 511 {
 512         for(;;)
 513                 idle();
 514 }
 515 
 516 #else
 517 
 518 /*
 519  *      Multiprocessor idle thread is in arch/...
 520  */
 521  
 522 extern int cpu_idle(void * unused);
 523 
 524 /*
 525  *      Activate a secondary processor.
 526  */
 527  
 528 asmlinkage void start_secondary(void)
     /*  */
 529 {
 530         trap_init();
 531         init_IRQ();
 532         smp_callin();
 533         cpu_idle(NULL);
 534 }
 535 
 536 
 537 
 538 /*
 539  *      Called by CPU#0 to activate the rest.
 540  */
 541  
 542 static void smp_init(void)
     /*  */
 543 {
 544         int i=0;
 545         smp_boot_cpus();
 546         
 547         /*
 548          *      Create the slave init tasks as sharing pid 0.
 549          */
 550 
 551         for(i=1;i<smp_num_cpus;i++)
 552         {
 553                 /*
 554                  *      We use kernel_thread for the idlers which are
 555                  *      unlocked tasks running in kernel space.
 556                  */
 557                 kernel_thread(cpu_idle, NULL, CLONE_PID);
 558                 /*
 559                  *      Assume linear processor numbering
 560                  */
 561                 current_set[i]=task[i];
 562                 current_set[i]->processor=i;
 563         }
 564 }               
 565 
 566 /*
 567  *      The autoprobe routines assume CPU#0 on the i386
 568  *      so we don't actually set the game in motion until
 569  *      they are finished.
 570  */
 571  
 572 static void smp_begin(void)
     /*  */
 573 {
 574         smp_threads_ready=1;
 575         smp_commence();
 576 }
 577         
 578 #endif
 579 
 580 /*
 581  *      Activate the first processor.
 582  */
 583  
 584 asmlinkage void start_kernel(void)
     /*  */
 585 {
 586         char * command_line;
 587 
 588 /*
 589  *      This little check will move.
 590  */
 591 
 592 #ifdef __SMP__
 593         static int first_cpu=1;
 594         
 595         if(!first_cpu)
 596                 start_secondary();
 597         first_cpu=0;
 598         
 599 #endif  
 600 /*
 601  * Interrupts are still disabled. Do necessary setups, then
 602  * enable them
 603  */
 604         setup_arch(&command_line, &memory_start, &memory_end);
 605         memory_start = paging_init(memory_start,memory_end);
 606         trap_init();
 607         init_IRQ();
 608         sched_init();
 609         time_init();
 610         parse_options(command_line);
 611 #ifdef CONFIG_MODULES
 612         init_modules();
 613 #endif
 614 #ifdef CONFIG_PROFILE
 615         if (!prof_shift)
 616 #ifdef CONFIG_PROFILE_SHIFT
 617                 prof_shift = CONFIG_PROFILE_SHIFT;
 618 #else
 619                 prof_shift = 2;
 620 #endif
 621 #endif
 622         if (prof_shift) {
 623                 prof_buffer = (unsigned long *) memory_start;
 624                 /* only text is profiled */
 625                 prof_len = (unsigned long) &_etext - (unsigned long) &_stext;
 626                 prof_len >>= prof_shift;
 627                 memory_start += prof_len * sizeof(unsigned long);
 628         }
 629         memory_start = console_init(memory_start,memory_end);
 630 #ifdef CONFIG_PCI
 631         memory_start = pci_init(memory_start,memory_end);
 632 #endif
 633         memory_start = kmalloc_init(memory_start,memory_end);
 634         sti();
 635         calibrate_delay();
 636         memory_start = inode_init(memory_start,memory_end);
 637         memory_start = file_table_init(memory_start,memory_end);
 638         memory_start = name_cache_init(memory_start,memory_end);
 639         mem_init(memory_start,memory_end);
 640         buffer_init();
 641         sock_init();
 642 #if defined(CONFIG_SYSVIPC) || defined(CONFIG_KERNELD)
 643         ipc_init();
 644 #endif
 645 #ifdef CONFIG_APM
 646         apm_bios_init();
 647 #endif
 648         dquot_init();
 649         arch_syms_export();
 650         sti();
 651         check_bugs();
 652 
 653         printk(linux_banner);
 654 #ifdef __SMP__
 655         smp_init();
 656 #endif
 657         sysctl_init();
 658         /* 
 659          *      We count on the initial thread going ok 
 660          *      Like idlers init is an unlocked kernel thread, which will
 661          *      make syscalls (and thus be locked).
 662          */
 663         kernel_thread(init, NULL, 0);
 664 /*
 665  * task[0] is meant to be used as an "idle" task: it may not sleep, but
 666  * it might do some general things like count free pages or it could be
 667  * used to implement a reasonable LRU algorithm for the paging routines:
 668  * anything that can be useful, but shouldn't take time from the real
 669  * processes.
 670  *
 671  * Right now task[0] just does a infinite idle loop.
 672  */
 673         cpu_idle(NULL);
 674 }
 675 
 676 static int printf(const char *fmt, ...)
     /*  */
 677 {
 678         va_list args;
 679         int i;
 680 
 681         va_start(args, fmt);
 682         write(1,printbuf,i=vsprintf(printbuf, fmt, args));
 683         va_end(args);
 684         return i;
 685 }
 686 
 687 static int do_rc(void * rc)
     /*  */
 688 {
 689         close(0);
 690         if (open(rc,O_RDONLY,0))
 691                 return -1;
 692         return execve("/bin/sh", argv_rc, envp_rc);
 693 }
 694 
 695 static int do_shell(void * shell)
     /*  */
 696 {
 697         close(0);close(1);close(2);
 698         setsid();
 699         (void) open("/dev/tty1",O_RDWR,0);
 700         (void) dup(0);
 701         (void) dup(0);
 702         return execve(shell, argv, envp);
 703 }
 704 
 705 static int init(void * unused)
     /*  */
 706 {
 707         int pid,i;
 708 
 709         /* Launch bdflush from here, instead of the old syscall way. */
 710         kernel_thread(bdflush, NULL, 0);
 711         /* Start the background pageout daemon. */
 712         kernel_thread(kswapd, NULL, 0);
 713 
 714         setup();
 715 
 716 #ifdef __SMP__
 717         /*
 718          *      With the devices probed and setup we can
 719          *      now enter SMP mode.
 720          */
 721         
 722         smp_begin();
 723 #endif  
 724 
 725         #ifdef CONFIG_UMSDOS_FS
 726         {
 727                 /*
 728                         When mounting a umsdos fs as root, we detect
 729                         the pseudo_root (/linux) and initialise it here.
 730                         pseudo_root is defined in fs/umsdos/inode.c
 731                 */
 732                 extern struct inode *pseudo_root;
 733                 if (pseudo_root != NULL){
 734                         current->fs->root = pseudo_root;
 735                         current->fs->pwd  = pseudo_root;
 736                 }
 737         }
 738         #endif
 739 
 740         (void) open("/dev/tty1",O_RDWR,0);
 741         (void) dup(0);
 742         (void) dup(0);
 743 
 744         if (!execute_command) {
 745                 execve("/etc/init",argv_init,envp_init);
 746                 execve("/bin/init",argv_init,envp_init);
 747                 execve("/sbin/init",argv_init,envp_init);
 748                 /* if this fails, fall through to original stuff */
 749 
 750                 pid = kernel_thread(do_rc, "/etc/rc", SIGCHLD);
 751                 if (pid>0)
 752                         while (pid != wait(&i))
 753                                 /* nothing */;
 754                 }
 755 
 756         while (1) {
 757                 pid = kernel_thread(do_shell,
 758                         execute_command ? execute_command : "/bin/sh",
 759                         SIGCHLD);
 760                 if (pid < 0) {
 761                         printf("Fork failed in init\n\r");
 762                         continue;
 763                 }
 764                 while (1)
 765                         if (pid == wait(&i))
 766                                 break;
 767                 printf("\n\rchild %d died with code %04x\n\r",pid,i);
 768                 sync();
 769         }
 770         return -1;
 771 }

/* */