distr/util/restart.c

   1 #include <stdio.h>
   2 #include "util.h"
   3
   4 #if (defined(sun) && ! defined(sparc)) || defined(vax)
   5
   6 #include <signal.h>
   7 #include <sys/types.h>
   8 #include <sys/time.h>
   9
  10 static char *save_stack_base;
  11 static char *stack_lo_addr;
  12 static char *stack_hi_addr;
  13 static int stack_size;
  14
  15 static int restart_global_flag;
  16 static char *old_file_name;
  17 static char *new_file_name;
  18
  19 char *util_save_sp;             /* set by util_restart_save_state() */
  20 extern char *sbrk();
  21 \f
  22 static void
  23 grow_stack()
  24 {
  25     int i, space[256];
  26
  27     for(i = 0; i < 256; i++) {
  28         space[i] = 0;
  29     }
  30     if ((char *) &i > stack_lo_addr) {
  31         grow_stack();
  32     }
  33 }
  34
  35
  36 /* ARGSUSED */
  37 static int
  38 handle_sigquit(int sig, int code, struct sigcontext *scp)
  39 {
  40     if (util_restart_save_state()) {
  41         /* we are restarting ! -- return from signal */
  42
  43     } else {
  44         /* copy stack to user data space */
  45         stack_lo_addr = util_save_sp;
  46         stack_size = stack_hi_addr - stack_lo_addr + 1;
  47         save_stack_base = sbrk(stack_size);
  48         (void) memcpy(save_stack_base, stack_lo_addr, stack_size);
  49
  50         /* write a new executable */
  51         (void) fprintf(stderr, "Writing executable %s ...\n", new_file_name);
  52         (void) util_save_image(old_file_name, new_file_name);
  53
  54         /* terminate if signal was a QUIT */
  55         if (sig == SIGQUIT) {
  56             (void) _exit(1);
  57         }
  58     }
  59 }
  60
  61
  62 static void
  63 restart_program()
  64 {
  65     (void) fprintf(stderr, "Continuing execution ...\n");
  66
  67     /* create the stack */
  68     grow_stack();
  69
  70 #ifdef vax
  71     asm("movl _util_save_sp,sp");
  72 #endif
  73 #ifdef sun
  74     asm("movl _util_save_sp,sp");
  75 #endif
  76
  77     /* copy the stack back from user space */
  78     (void) memcpy(stack_lo_addr, save_stack_base, stack_size);
  79
  80     /* remove the sbrk for the stack */
  81     if (sbrk(-stack_size) < 0) {
  82         perror("sbrk");
  83     }
  84
  85     util_restart_restore_state();       /* jump back into handle_sigquit() */
  86 }
  87 \f
  88 void
  89 util_restart(char const *old, char const *neW, int interval)
  90 {
  91     struct itimerval itimer;
  92
  93 #ifdef vax
  94 #ifdef ultrix
  95     stack_hi_addr = (char *) 0x7fffe3ff;        /* ultrix */
  96 #else
  97     stack_hi_addr = (char *) 0x7fffebff;        /* bsd 4.3 */
  98 #endif
  99 #endif
 100 #ifdef sun
 101     stack_hi_addr = (char *) 0x0effffff;        /* Sun OS 3.2, 3.4 */
 102 #endif
 103
 104     old_file_name = old;
 105     new_file_name = neW;
 106
 107     (void) signal(SIGQUIT, handle_sigquit);
 108
 109     if (interval > 0) {
 110         (void) signal(SIGVTALRM, handle_sigquit);
 111         itimer.it_interval.tv_sec = interval;
 112         itimer.it_interval.tv_usec = 0;
 113         itimer.it_value.tv_sec = interval;
 114         itimer.it_value.tv_usec = 0;
 115         if (setitimer(ITIMER_VIRTUAL, &itimer, (struct itimerval *) 0) < 0) {
 116             perror("setitimer");
 117             exit(1);
 118         }
 119     }
 120
 121     if (restart_global_flag) {
 122         restart_program();
 123     }
 124     restart_global_flag = 1;
 125 }
 126
 127 #else
 128
 129 /* ARGSUSED */
 130 void
 131 util_restart(char const *old, char const *neW, int interval)
 132 {
 133     (void) fprintf(stderr,
 134         "util_restart: not supported on your operating system/hardware\n");
 135 }
 136
 137 #endif