init.c

   1 #include "internal.h"
   2 #include <stdio.h>
   3 #include <stdlib.h>
   4 #include <stdarg.h>
   5 #include <unistd.h>
   6 #include <errno.h>
   7 #include <signal.h>
   8 #include <termios.h>
   9 #include <sys/types.h>
  10 #include <sys/fcntl.h>
  11 #include <sys/wait.h>
  12 #include <string.h>
  13 #include <sys/mount.h>
  14 #include <sys/reboot.h>
  15 #include <sys/kdaemon.h>
  16 #include <sys/swap.h>
  17 #include <sys/sysmacros.h>
  18
  19 const char              init_usage[] = "Used internally by the system.";
  20 char                    console[16] = "";
  21 const char *    default_console = "/dev/tty1";
  22 char *                  first_terminal = NULL;
  23 const char *    second_terminal = "/dev/tty2";
  24 const char              log[] = "/dev/tty3";
  25 char * term_ptr = NULL;
  26
  27 static void
  28 message(const char * terminal, const char * pattern, ...)
  29 {
  30         int     fd;
  31         FILE *  con = 0;
  32         va_list arguments;
  33
  34         /*
  35          * Open the console device each time a message is printed. If the user
  36          * has switched consoles, the open will get the new console. If we kept
  37          * the console open, we'd always print to the same one.
  38          */
  39         if ( ((fd = open(terminal, O_WRONLY|O_NOCTTY)) < 0)
  40          ||  ((con = fdopen(fd, "w")) == NULL) )
  41                 return;
  42
  43         va_start(arguments, pattern);
  44         vfprintf(con, pattern, arguments);
  45         va_end(arguments);
  46         fclose(con);
  47 }
  48
  49 static int
  50 waitfor(int pid)
  51 {
  52         int     status;
  53         int     wpid;
  54
  55         message(log, "Waiting for process %d.\n", pid);
  56         while ( (wpid = wait(&status)) != pid ) {
  57                 if ( wpid > 0 ) {
  58                         message(
  59                          log
  60                         ,"pid %d exited, status=%x.\n"
  61                         ,wpid
  62                         ,status);
  63                 }
  64         }
  65         return wpid;
  66 }
  67
  68 static int
  69 run(const char* program, const char* const* arguments,
  70         const char* terminal, int get_enter)
  71 {
  72         static const char       control_characters[] = {
  73                 '\003',
  74                 '\034',
  75                 '\177',
  76                 '\025',
  77                 '\004',
  78                 '\0',
  79                 '\1',
  80                 '\0',
  81                 '\021',
  82                 '\023',
  83                 '\032',
  84                 '\0',
  85                 '\022',
  86                 '\017',
  87                 '\027',
  88                 '\026',
  89                 '\0'
  90         };
  91
  92         static char * environment[] = {
  93                 "HOME=/",
  94                 "PATH=/bin:/sbin:/usr/bin:/usr/sbin",
  95                 "SHELL=/bin/sh",
  96                 0,
  97                 "USER=root",
  98                 0
  99         };
 100
 101         static const char       press_enter[] =
 102  "\nPlease press Enter to activate this console. ";
 103
 104         int     pid;
 105
 106         environment[3]=term_ptr;
 107
 108         pid = fork();
 109         if ( pid == 0 ) {
 110                 struct termios  t;
 111                 const char * const * arg;
 112
 113                 close(0);
 114                 close(1);
 115                 close(2);
 116                 setsid();
 117
 118                 open(terminal, O_RDWR);
 119                 dup(0);
 120                 dup(0);
 121                 tcsetpgrp(0, getpgrp());
 122
 123                 tcgetattr(0, &t);
 124                 memcpy(t.c_cc, control_characters, sizeof(control_characters));
 125                 t.c_line = 0;
 126                 t.c_iflag = ICRNL|IXON|IXOFF;
 127                 t.c_oflag = OPOST|ONLCR;
 128                 t.c_lflag = ISIG|ICANON|ECHO|ECHOE|ECHOK|ECHOCTL|ECHOKE|IEXTEN;
 129                 tcsetattr(0, TCSANOW, &t);
 130
 131                 if ( get_enter ) {
 132                         /*
 133                          * Save memory by not exec-ing anything large (like a shell)
 134                          * before the user wants it. This is critical if swap is not
 135                          * enabled and the system has low memory. Generally this will
 136                          * be run on the second virtual console, and the first will
 137                          * be allowed to start a shell or whatever an init script
 138                          * specifies.
 139                          */
 140                         char    c;
 141                         write(1, press_enter, sizeof(press_enter) - 1);
 142                         read(0, &c, 1);
 143                 }
 144
 145                 message(log, "Executing ");
 146                 arg = arguments;
 147                 while ( *arg != 0 )
 148                         message(log, "%s ", *arg++);
 149                 message(log, "\n");
 150
 151                 execve(program, (char * *)arguments, (char * *)environment);
 152                 message(log, "%s: could not execute: %s.\r\n", program, strerror(errno));
 153                 exit(-1);
 154         }
 155         return pid;
 156 }
 157
 158 static int
 159 mem_total()
 160 {
 161   char s[80];
 162   char *p;
 163   FILE *f;
 164   const char pattern[]="MemTotal:";
 165
 166   f=fopen("/proc/meminfo","r");
 167   while (NULL != fgets(s,79,f)) {
 168     p=strstr(s, pattern);
 169     if (NULL != p) {
 170       fclose(f);
 171       return(atoi(p+strlen(pattern)));
 172     }
 173   }
 174   return -1;
 175 }
 176
 177 static void
 178 set_free_pages()
 179 {
 180   char s[80];
 181   FILE *f;
 182
 183   f=fopen("/proc/sys/vm/freepages","r");
 184   fgets(s,79,f);
 185   if (atoi(s) < 32) {
 186     fclose(f);
 187     f=fopen("/proc/sys/vm/freepages","w");
 188     fprintf(f,"30\t40\t50\n");
 189     printf("\nIncreased /proc/sys/vm/freepages values to 30/40/50\n");
 190   }
 191   fclose(f);
 192 }
 193
 194 static void
 195 shutdown_system(int do_reboot)
 196 {
 197         static const char * const umount_args[] = {"/bin/umount", "-a", "-n", 0};
 198
 199         sync();
 200         /* Allow Ctrl-Alt-Del to reboot system. */
 201         reboot(RB_ENABLE_CAD);
 202
 203         /* Send signals to every process _except_ pid 1 */
 204         message(console, "Sending SIGHUP to all processes.\r\n");
 205         kill(-1, SIGHUP);
 206         sleep(2);
 207         sync();
 208         message(console, "Sending SIGKILL to all processes.\r\n");
 209         kill(-1, SIGKILL);
 210         sleep(1);
 211         waitfor(run("/bin/umount", umount_args, console, 0));
 212         sync();
 213         bdflush(1, 0);
 214         sync();
 215         reboot(do_reboot ?RB_AUTOBOOT : RB_HALT_SYSTEM);
 216         exit(0);
 217 }
 218
 219 static void
 220 halt_signal(int sig)
 221 {
 222         shutdown_system(0);
 223 }
 224
 225 static void
 226 reboot_signal(int sig)
 227 {
 228         shutdown_system(1);
 229 }
 230
 231 static void
 232 exit_signal(int sig)
 233 {
 234
 235   /* initrd doesn't work anyway */
 236
 237   shutdown_system(1);
 238
 239         /* This is used on the initial ramdisk */
 240
 241   /*    message(log, "Init exiting.");
 242         exit(0);
 243         */
 244 }
 245
 246 void
 247 configure_terminals( int serial_cons )
 248 {
 249         //struct stat statbuf;
 250         char *tty;
 251
 252         switch (serial_cons) {
 253         case 1:
 254                 strcpy( console, "/dev/ttyS0" );
 255                 break;
 256         case 2:
 257                 strcpy( console, "/dev/ttyS1" );
 258                 break;
 259         default:
 260                 tty = ttyname(0);
 261                 if (tty) {
 262                         strcpy( console, tty );
 263                         if (!strncmp( tty, "/dev/ttyS", 9 ))
 264                                 serial_cons=1;
 265                 }
 266                 else
 267                         /* falls back to /dev/tty1 if an error occurs */
 268                         strcpy( console, default_console );
 269         }
 270         if (!first_terminal)
 271                 first_terminal = console;
 272         if (serial_cons && !strncmp(term_ptr,"TERM=linux",10))
 273                 term_ptr = "TERM=vt100";
 274 }
 275
 276 extern int
 277 init_main(int argc, char * * argv)
 278 {
 279         static const char* const    rc = "etc/rc";
 280         const char *                arguments[100];
 281         int                         run_rc = 1;
 282         int                         j;
 283         int                         pid1 = 0;
 284         int                         pid2 = 0;
 285         int                         create_swap= -1;
 286         struct stat                 statbuf;
 287         const char *                tty_commands[2] = { "bin/sh", "bin/sh"};
 288         char                        swap[20];
 289         int                         serial_console = 0;
 290
 291         /*
 292          * If I am started as /linuxrc instead of /sbin/init, I don't have the
 293          * environment that init expects. I can't fix the signal behavior. Try
 294          * to divorce from the controlling terminal with setsid(). This won't work
 295          * if I am the process group leader.
 296          */
 297         setsid();
 298
 299         signal(SIGUSR1, halt_signal);
 300         signal(SIGUSR2, reboot_signal);
 301         signal(SIGINT, reboot_signal);
 302         signal(SIGTERM, exit_signal);
 303
 304         reboot(RB_DISABLE_CAD);
 305
 306         message(log, "%s: started. ", argv[0]);
 307
 308         for ( j = 1; j < argc; j++ ) {
 309                 if ( strcmp(argv[j], "single") == 0 ) {
 310                         run_rc = 0;
 311                         tty_commands[0] = "bin/sh";
 312                         tty_commands[1] = 0;
 313                 }
 314         }
 315         for ( j = 0; __environ[j] != 0; j++ ) {
 316                 if ( strncmp(__environ[j], "tty", 3) == 0
 317                  && __environ[j][3] >= '1'
 318                  && __environ[j][3] <= '2'
 319                  && __environ[j][4] == '=' ) {
 320                         const char * s = &__environ[j][5];
 321
 322                         if ( *s == 0 || strcmp(s, "off") == 0 )
 323                                 s = 0;
 324
 325                         tty_commands[__environ[j][3] - '1'] = s;
 326                 }
 327                 /* Should catch the syntax of Sparc kernel console setting.   */
 328                 /* The kernel does not recognize a serial console when getting*/
 329                 /* console=/dev/ttySX !! */
 330                 else if ( strcmp(__environ[j], "console=ttya") == 0 ) {
 331                         serial_console=1;
 332                 }
 333                 else if ( strcmp(__environ[j], "console=ttyb") == 0 ) {
 334                         serial_console=2;
 335                 }
 336                 /* standard console settings */
 337                 else if ( strncmp(__environ[j], "console=", 8) == 0 ) {
 338                         first_terminal=&(__environ[j][8]);
 339                 }
 340                 else if ( strncmp(__environ[j], "TERM=", 5) == 0) {
 341                         term_ptr=__environ[j];
 342                 }
 343         }
 344         configure_terminals( serial_console );
 345
 346         printf("mounting /proc ...\n");
 347         if (mount("/proc","/proc","proc",0,0)) {
 348           perror("mounting /proc failed\n");
 349         }
 350         printf("\tdone.\n");
 351
 352         set_free_pages();
 353
 354         /* not enough memory to do anything useful*/
 355         if (mem_total() < 2000) {
 356           int retval;
 357           retval= stat("/etc/swappartition",&statbuf);
 358           if (retval) {
 359             printf("You do not have enough RAM, sorry.\n");
 360             while (1) { sleep(1);}
 361           } else { /* everything OK */
 362             FILE *f;
 363
 364             f=fopen("/etc/swappartition","r");
 365             fgets(swap,19,f);
 366             fclose(f);
 367             *(strstr(swap,"\n"))='\0';
 368
 369             if (swapon(swap,0)) {
 370               perror("swapon failed\n");
 371             } else {
 372               f=fopen("/etc/swaps","w");
 373               fprintf(f,"%s none swap rw 0 0",swap);
 374                 fclose(f);
 375               create_swap = 0;
 376             }
 377           }
 378         }
 379
 380         /*
 381          * Don't modify **argv directly, it would show up in the "ps" display.
 382          * I don't want "init" to look like "rc".
 383          */
 384         arguments[0] = rc;
 385         for ( j = 1; j < argc; j++ ) {
 386                 arguments[j] = argv[j];
 387         }
 388         arguments[j] = 0;
 389
 390         if ( run_rc ) {
 391                 run(rc, arguments, console, 0);
 392                 //waitfor(run(rc, arguments, console, 0));
 393         }
 394
 395         if ( 0 == create_swap) {
 396           if (unlink("/etc/swappartition")) {
 397             perror("unlinking /etc/swappartition");
 398           }
 399         }
 400
 401         arguments[0] = "-sh";
 402         arguments[1] = 0;
 403         for ( ; ; ) {
 404                 int     wpid;
 405                 int     status;
 406
 407                 if ( pid1 == 0 && tty_commands[0] ) {
 408                         /* Ask before starting a shell */
 409                         /*
 410                          arguments[0] = tty_commands[0];
 411                          */
 412                         pid1 = run(tty_commands[0], arguments, first_terminal, 1);
 413                 }
 414                 if ( pid2 == 0 && tty_commands[1] ) {
 415                         pid2 = run(tty_commands[1], arguments, second_terminal, 1);
 416                 }
 417                 wpid = wait(&status);
 418                 if ( wpid > 0 ) {
 419                         /* DEBUGGING */
 420                         message(log, "pid %d exited, status=%x.\n", wpid, status);
 421                 }
 422                 if ( wpid == pid1 ) {
 423                   pid1 = 0;
 424                 }
 425                 if ( wpid == pid2 )
 426                         pid2 = 0;
 427         }
 428 }
 429