C:/Users/Dennis/src/lang/russell.orig/src/gc/os_dep.c

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/*
 * Copyright (c) 1991-1993 by Xerox Corporation.  All rights reserved.
 *
 * THIS MATERIAL IS PROVIDED AS IS, WITH ABSOLUTELY NO WARRANTY EXPRESSED
 * OR IMPLIED.  ANY USE IS AT YOUR OWN RISK.
 *
 * Permission is hereby granted to copy this garbage collector for any purpose,
 * provided the above notices are retained on all copies.
 */
# include "gc_private.h"
# include <stdio.h>
# include <signal.h>

/* Blatantly OS dependent routines, except for those that are related   */
/* dynamic loading.                                                     */

/* Disable and enable signals during nontrivial allocations     */

# ifdef OS2

# define INCL_DOSEXCEPTIONS
# define INCL_DOSPROCESS
# define INCL_DOSERRORS
# define INCL_DOSMODULEMGR
# include <os2.h>

/* A kludge to get around what appears to be a header file bug */
# ifndef WORD
#   define WORD unsigned short
# endif
# ifndef DWORD
#   define DWORD unsigned long
# endif

# define EXE386 1
# include <newexe.h>
# include <exe386.h>

void GC_disable_signals(void)
{
    ULONG nest;
    
    DosEnterMustComplete(&nest);
    if (nest != 1) ABORT("nested GC_disable_signals");
}

void GC_enable_signals(void)
{
    ULONG nest;
    
    DosExitMustComplete(&nest);
    if (nest != 0) ABORT("GC_enable_signals");
}


# else

#  ifndef PCR

#   ifdef sigmask
        /* Use the traditional BSD interface */
#       define SIGSET_T int
#       define SIG_DEL(set, signal) (set) &= ~(sigmask(signal))
#       define SIG_FILL(set)  (set) = 0x7fffffff
          /* Setting the leading bit appears to provoke a bug in some   */
          /* longjmp implementations.  Most systems appear not to have  */
          /* a signal 32.                                               */
#       define SIGSETMASK(old, new) (old) = sigsetmask(new)
#   else
        /* Use POSIX/SYSV interface     */
#       define SIGSET_T sigset_t
#       define SIG_DEL(set, signal) sigdelset(&(set), (signal))
#       define SIG_FILL(set) sigfillset(&set)
#       define SIGSETMASK(old, new) sigprocmask(SIG_SETMASK, &(new), &(old))
#   endif

static bool mask_initialized = FALSE;

static SIGSET_T new_mask;

static SIGSET_T old_mask;

static SIGSET_T dummy;

void GC_disable_signals()
{
    if (!mask_initialized) {
        SIG_FILL(new_mask);

        SIG_DEL(new_mask, SIGSEGV);
        SIG_DEL(new_mask, SIGILL);
        SIG_DEL(new_mask, SIGQUIT);
#       ifdef SIGBUS
            SIG_DEL(new_mask, SIGBUS);
#       endif
#       ifdef SIGIOT
            SIG_DEL(new_mask, SIGIOT);
#       endif
#       ifdef SIGEMT
            SIG_DEL(new_mask, SIGEMT);
#       endif
#       ifdef SIGTRAP
            SIG_DEL(new_mask, SIGTRAP);
#       endif 
        mask_initialized = TRUE;
    }     
    SIGSETMASK(old_mask,new_mask);
}

void GC_enable_signals()
{
    SIGSETMASK(dummy,old_mask);
}

#  endif  /* !PCR */

# endif 
/*
 * Find the base of the stack.
 * Used only in single-threaded environment.
 * With threads, GC_mark_roots needs to know how to do this.
 * Called with allocator lock held.
 */

# ifdef OS2

ptr_t GC_get_stack_base()
{
    PTIB ptib;
    PPIB ppib;
    
    if (DosGetInfoBlocks(&ptib, &ppib) != NO_ERROR) {
        GC_err_printf0("DosGetInfoBlocks failed\n");
        ABORT("DosGetInfoBlocks failed\n");
    }
    return((ptr_t)(ptib -> tib_pstacklimit));
}

# else

# if !defined(THREADS) && !defined(STACKBOTTOM) && defined(HEURISTIC2)
  /* Some tools to implement HEURISTIC2 */
#   define MIN_PAGE_SIZE 256    /* Smallest conceivable page size, bytes */
#   include <setjmp.h>
    /* static */ jmp_buf GC_jmp_buf;
    
    /*ARGSUSED*/
    void GC_fault_handler(sig)
    int sig;
    {
        longjmp(GC_jmp_buf, 1);
    }
# endif

ptr_t GC_get_stack_base()
{
    word dummy;
    static ptr_t result;
                /* Needs to be static, since otherwise it may not be    */
                /* preserved across the longjmp.  Can safely be         */
                /* static since it's only called once, with the         */
                /* allocation lock held.                                */
#   ifdef __STDC__
        typedef void (*handler)(int);
#   else
        typedef void (*handler)();
#   endif
#   ifdef HEURISTIC2
      static handler old_segv_handler, old_bus_handler;
                /* See above for static declaration.                    */
#   endif
#   define STACKBOTTOM_ALIGNMENT_M1 0xffffff

#   ifdef STACKBOTTOM
        return(STACKBOTTOM);
#   else
#       ifdef HEURISTIC1
#          ifdef STACK_GROWS_DOWN
             result = (ptr_t)((((word)(&dummy))
                               + STACKBOTTOM_ALIGNMENT_M1)
                              & ~STACKBOTTOM_ALIGNMENT_M1);
#          else
             result = (ptr_t)(((word)(&dummy))
                              & ~STACKBOTTOM_ALIGNMENT_M1);
#          endif
#       endif /* HEURISTIC1 */
#       ifdef HEURISTIC2
           old_segv_handler = signal(SIGSEGV, GC_fault_handler);
#          ifdef SIGBUS
             old_bus_handler = signal(SIGBUS, GC_fault_handler);
#          endif
           if (setjmp(GC_jmp_buf) == 0) {
             result = (ptr_t)(((word)(&dummy))
                              & ~(MIN_PAGE_SIZE-1));
             for (;;) {
#                ifdef STACK_GROWS_DOWN
                   result += MIN_PAGE_SIZE;
#                else
                   result -= MIN_PAGE_SIZE;
#                endif
                 GC_noop(*result);
             }
           }
           (void) signal(SIGSEGV, old_segv_handler);
#          ifdef SIGBUS
               (void) signal(SIGBUS, old_bus_handler);
#          endif
#          ifdef STACK_GROWS_UP
              result += MIN_PAGE_SIZE;
#          endif
#       endif /* HEURISTIC2 */
        return(result);
#   endif /* STACKBOTTOM */
}

# endif /* ! OS2 */

/*
 * Register static data segment(s) as roots.
 * If more data segments are added later then they need to be registered
 * add that point (as we do with SunOS dynamic loading),
 * or GC_mark_roots needs to check for them (as we do with PCR).
 * Called with allocator lock held.
 */

# ifdef OS2

void GC_register_data_segments()
{
    PTIB ptib;
    PPIB ppib;
    HMODULE module_handle;
#   define PBUFSIZ 512
    UCHAR path[PBUFSIZ];
    FILE * myexefile;
    struct exe_hdr hdrdos;      /* MSDOS header.        */
    struct e32_exe hdr386;      /* Real header for my executable */
    struct o32_obj seg; /* Currrent segment */
    int nsegs;
    
    
    if (DosGetInfoBlocks(&ptib, &ppib) != NO_ERROR) {
        GC_err_printf0("DosGetInfoBlocks failed\n");
        ABORT("DosGetInfoBlocks failed\n");
    }
    module_handle = ppib -> pib_hmte;
    if (DosQueryModuleName(module_handle, PBUFSIZ, path) != NO_ERROR) {
        GC_err_printf0("DosQueryModuleName failed\n");
        ABORT("DosGetInfoBlocks failed\n");
    }
    myexefile = fopen(path, "rb");
    if (myexefile == 0) {
        GC_err_puts("Couldn't open executable ");
        GC_err_puts(path); GC_err_puts("\n");
        ABORT("Failed to open executable\n");
    }
    if (fread((char *)(&hdrdos), 1, sizeof hdrdos, myexefile) < sizeof hdrdos) {
        GC_err_puts("Couldn't read MSDOS header from ");
        GC_err_puts(path); GC_err_puts("\n");
        ABORT("Couldn't read MSDOS header");
    }
    if (E_MAGIC(hdrdos) != EMAGIC) {
        GC_err_puts("Executable has wrong DOS magic number: ");
        GC_err_puts(path); GC_err_puts("\n");
        ABORT("Bad DOS magic number");
    }
    if (fseek(myexefile, E_LFANEW(hdrdos), SEEK_SET) != 0) {
        GC_err_puts("Seek to new header failed in ");
        GC_err_puts(path); GC_err_puts("\n");
        ABORT("Bad DOS magic number");
    }
    if (fread((char *)(&hdr386), 1, sizeof hdr386, myexefile) < sizeof hdr386) {
        GC_err_puts("Couldn't read MSDOS header from ");
        GC_err_puts(path); GC_err_puts("\n");
        ABORT("Couldn't read OS/2 header");
    }
    if (E32_MAGIC1(hdr386) != E32MAGIC1 || E32_MAGIC2(hdr386) != E32MAGIC2) {
        GC_err_puts("Executable has wrong OS/2 magic number:");
        GC_err_puts(path); GC_err_puts("\n");
        ABORT("Bad OS/2 magic number");
    }
    if ( E32_BORDER(hdr386) != E32LEBO || E32_WORDER(hdr386) != E32LEWO) {
        GC_err_puts("Executable %s has wrong byte order: ");
        GC_err_puts(path); GC_err_puts("\n");
        ABORT("Bad byte order");
    }
    if ( E32_CPU(hdr386) == E32CPU286) {
        GC_err_puts("GC can't handle 80286 executables: ");
        GC_err_puts(path); GC_err_puts("\n");
        EXIT();
    }
    if (fseek(myexefile, E_LFANEW(hdrdos) + E32_OBJTAB(hdr386),
              SEEK_SET) != 0) {
        GC_err_puts("Seek to object table failed: ");
        GC_err_puts(path); GC_err_puts("\n");
        ABORT("Seek to object table failed");
    }
    for (nsegs = E32_OBJCNT(hdr386); nsegs > 0; nsegs--) {
      int flags;
      if (fread((char *)(&seg), 1, sizeof seg, myexefile) < sizeof seg) {
        GC_err_puts("Couldn't read obj table entry from ");
        GC_err_puts(path); GC_err_puts("\n");
        ABORT("Couldn't read obj table entry");
      }
      flags = O32_FLAGS(seg);
      if (!(flags & OBJWRITE)) continue;
      if (!(flags & OBJREAD)) continue;
      if (flags & OBJINVALID) {
          GC_err_printf0("Object with invalid pages?\n");
          continue;
      } 
      GC_add_roots_inner(O32_BASE(seg), O32_BASE(seg)+O32_SIZE(seg));
    }
}

# else

void GC_register_data_segments()
{
    extern int end;
 
#   ifndef PCR      
      GC_add_roots_inner(DATASTART, (char *)(&end));
#   endif
    /* Dynamic libraries are added at every collection, since they may  */
    /* change.                                                          */
}

# endif  /* ! OS2 */

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