Subversion Repositories or1k

/*

 * tclLoadAout.c --

 *

 *      This procedure provides a version of the TclLoadFile that

 *      provides pseudo-static linking using version-7 compatible

 *      a.out files described in either sys/exec.h or sys/a.out.h.

 *

 * Copyright (c) 1995, by General Electric Company. All rights reserved.

 *

 * See the file "license.terms" for information on usage and redistribution

 * of this file, and for a DISCLAIMER OF ALL WARRANTIES.

 *

 * This work was supported in part by the ARPA Manufacturing Automation

 * and Design Engineering (MADE) Initiative through ARPA contract

 * F33615-94-C-4400.

 *

 * RCS: @(#) $Id: tclLoadAout.c,v 1.1.1.1 2002-01-16 10:25:37 markom Exp $

 */

#include "tclInt.h"

#include <fcntl.h>

#ifdef HAVE_EXEC_AOUT_H

#   include <sys/exec_aout.h>

#endif

/*

 * Some systems describe the a.out header in sys/exec.h, and some in

 * a.out.h.

 */

#ifdef USE_SYS_EXEC_H

#include <sys/exec.h>

#endif

#ifdef USE_A_OUT_H

#include <a.out.h>

#endif

#ifdef USE_SYS_EXEC_AOUT_H

#include <sys/exec_aout.h>

#define a_magic a_midmag

#endif

/*

 * TCL_LOADSHIM is the amount by which to shim the break when loading

 */

#ifndef TCL_LOADSHIM

#define TCL_LOADSHIM 0x4000L

#endif

/*

 * TCL_LOADALIGN must be a power of 2, and is the alignment to which

 * to force the origin of load modules

 */

#ifndef TCL_LOADALIGN

#define TCL_LOADALIGN 0x4000L

#endif

/*

 * TCL_LOADMAX is the maximum size of a load module, and is used as

 * a sanity check when loading

 */

#ifndef TCL_LOADMAX

#define TCL_LOADMAX 2000000L

#endif

/*

 * Kernel calls that appear to be missing from the system .h files:

 */

extern char * brk _ANSI_ARGS_((char *));

extern char * sbrk _ANSI_ARGS_((size_t));

/*

 * The static variable SymbolTableFile contains the file name where the

 * result of the last link was stored.  The file is kept because doing so

 * allows one load module to use the symbols defined in another.

 */

static char * SymbolTableFile = NULL;

/*

 * Type of the dictionary function that begins each load module.

 */

typedef Tcl_PackageInitProc * (* DictFn) _ANSI_ARGS_ ((char * symbol));

/*

 * Prototypes for procedures referenced only in this file:

 */

static int FindLibraries _ANSI_ARGS_((Tcl_Interp * interp, char * fileName,

                                      Tcl_DString * buf));

static void UnlinkSymbolTable _ANSI_ARGS_((void));

/*

 *----------------------------------------------------------------------

 *

 * TclLoadFile --

 *

 *      Dynamically loads a binary code file into memory and returns

 *      the addresses of two procedures within that file, if they

 *      are defined.

 *

 * Results:

 *      A standard Tcl completion code.  If an error occurs, an error

 *      message is left in interp->result.  *proc1Ptr and *proc2Ptr

 *      are filled in with the addresses of the symbols given by

 *      *sym1 and *sym2, or NULL if those symbols can't be found.

 *

 * Side effects:

 *      New code suddenly appears in memory.

 *

 *

 * Bugs:

 *      This function does not attempt to handle the case where the

 *      BSS segment is not executable.  It will therefore fail on

 *      Encore Multimax, Pyramid 90x, and similar machines.  The

 *      reason is that the mprotect() kernel call, which would

 *      otherwise be employed to mark the newly-loaded text segment

 *      executable, results in a system crash on BSD/386.

 *

 *      In an effort to make it fast, this function eschews the

 *      technique of linking the load module once, reading its header

 *      to determine its size, allocating memory for it, and linking

 *      it again.  Instead, it `shims out' memory allocation by

 *      placing the module TCL_LOADSHIM bytes beyond the break,

 *      and assuming that any malloc() calls required to run the

 *      linker will not advance the break beyond that point.  If

 *      the break is advanced beyonnd that point, the load will

 *      fail with an `inconsistent memory allocation' error.

 *      It perhaps ought to retry the link, but the failure has

 *      not been observed in two years of daily use of this function.

 *----------------------------------------------------------------------

 */

int

TclLoadFile(interp, fileName, sym1, sym2, proc1Ptr, proc2Ptr)

    Tcl_Interp *interp;         /* Used for error reporting. */

    char *fileName;             /* Name of the file containing the desired

                                 * code. */

    char *sym1, *sym2;          /* Names of two procedures to look up in

                                 * the file's symbol table. */

    Tcl_PackageInitProc **proc1Ptr, **proc2Ptr;

                                /* Where to return the addresses corresponding

                                 * to sym1 and sym2. */

{

  char * inputSymbolTable;      /* Name of the file containing the

                                 * symbol table from the last link. */

  Tcl_DString linkCommandBuf;   /* Command to do the run-time relocation

                                 * of the module.*/

  char * linkCommand;

  char relocatedFileName [L_tmpnam];

                                /* Name of the file holding the relocated */

                                /* text of the module */

  int relocatedFd;              /* File descriptor of the file holding

                                 * relocated text */

  struct exec relocatedHead;    /* Header of the relocated text */

  unsigned long relocatedSize;  /* Size of the relocated text */

  char * startAddress;          /* Starting address of the module */

  DictFn dictionary;            /* Dictionary function in the load module */

  int status;                   /* Status return from Tcl_ calls */

  char * p;

  /* Find the file that contains the symbols for the run-time link. */

  if (SymbolTableFile != NULL) {

    inputSymbolTable = SymbolTableFile;

  } else if (tclExecutableName == NULL) {

    Tcl_SetResult (interp, "can't find the tclsh executable", TCL_STATIC);

    return TCL_ERROR;

  } else {

    inputSymbolTable = tclExecutableName;

  }

  /* Construct the `ld' command that builds the relocated module */

  tmpnam (relocatedFileName);

  Tcl_DStringInit (&linkCommandBuf);

  Tcl_DStringAppend (&linkCommandBuf, "exec ld -o ", -1);

  Tcl_DStringAppend (&linkCommandBuf, relocatedFileName, -1);

#if defined(__mips) || defined(mips)

  Tcl_DStringAppend (&linkCommandBuf, " -G 0 ", -1);

#endif

  Tcl_DStringAppend (&linkCommandBuf, " -u TclLoadDictionary_", -1);

  TclGuessPackageName(fileName, &linkCommandBuf);

  Tcl_DStringAppend (&linkCommandBuf, " -A ", -1);

  Tcl_DStringAppend (&linkCommandBuf, inputSymbolTable, -1);

  Tcl_DStringAppend (&linkCommandBuf, " -N -T XXXXXXXX ", -1);

  Tcl_DStringAppend (&linkCommandBuf, fileName, -1);

  Tcl_DStringAppend (&linkCommandBuf, " ", -1);

  if (FindLibraries (interp, fileName, &linkCommandBuf) != TCL_OK) {

    Tcl_DStringFree (&linkCommandBuf);

    return TCL_ERROR;

  }

  linkCommand = Tcl_DStringValue (&linkCommandBuf);

  /* Determine the starting address, and plug it into the command */

  startAddress = (char *) (((unsigned long) sbrk (0)

                            + TCL_LOADSHIM + TCL_LOADALIGN - 1)

                           & (- TCL_LOADALIGN));

  p = strstr (linkCommand, "-T") + 3;

  sprintf (p, "%08lx", (long) startAddress);

  p [8] = ' ';

  /* Run the linker */

  status = Tcl_Eval (interp, linkCommand);

  Tcl_DStringFree (&linkCommandBuf);

  if (status != 0) {

    return TCL_ERROR;

  }

  /* Open the linker's result file and read the header */

  relocatedFd = open (relocatedFileName, O_RDONLY);

  if (relocatedFd < 0) {

    goto ioError;

  }

  status= read (relocatedFd, (char *) & relocatedHead, sizeof relocatedHead);

  if (status < sizeof relocatedHead) {

    goto ioError;

  }

  /* Check the magic number */

  if (relocatedHead.a_magic != OMAGIC) {

    Tcl_AppendResult (interp, "bad magic number in intermediate file \"",

                      relocatedFileName, "\"", (char *) NULL);

    goto failure;

  }

  /* Make sure that memory allocation is still consistent */

  if ((unsigned long) sbrk (0) > (unsigned long) startAddress) {

    Tcl_SetResult (interp, "can't load, memory allocation is inconsistent.",

                   TCL_STATIC);

    goto failure;

  }

  /* Make sure that the relocated module's size is reasonable */

  relocatedSize = relocatedHead.a_text + relocatedHead.a_data

    + relocatedHead.a_bss;

  if (relocatedSize > TCL_LOADMAX) {

    Tcl_SetResult (interp, "module too big to load", TCL_STATIC);

    goto failure;

  }

  /* Advance the break to protect the loaded module */

  (void) brk (startAddress + relocatedSize);

  /* Seek to the start of the module's text */

#if defined(__mips) || defined(mips)

  status = lseek (relocatedFd,

                  N_TXTOFF (relocatedHead.ex_f, relocatedHead.ex_o),

                  SEEK_SET);

#else

  status = lseek (relocatedFd, N_TXTOFF (relocatedHead), SEEK_SET);

#endif

  if (status < 0) {

    goto ioError;

  }

  /* Read in the module's text and data */

  relocatedSize = relocatedHead.a_text + relocatedHead.a_data;

  if (read (relocatedFd, startAddress, relocatedSize) < relocatedSize) {

    brk (startAddress);

  ioError:

    Tcl_AppendResult (interp, "error on intermediate file \"",

                      relocatedFileName, "\": ", Tcl_PosixError (interp),

                      (char *) NULL);

  failure:

    (void) unlink (relocatedFileName);

    return TCL_ERROR;

  }

  /* Close the intermediate file. */

  (void) close (relocatedFd);

  /* Arrange things so that intermediate symbol tables eventually get

   * deleted. */

  if (SymbolTableFile != NULL) {

    UnlinkSymbolTable ();

  } else {

    atexit (UnlinkSymbolTable);

  }

  SymbolTableFile = ckalloc (strlen (relocatedFileName) + 1);

  strcpy (SymbolTableFile, relocatedFileName);

  /* Look up the entry points in the load module's dictionary. */

  dictionary = (DictFn) startAddress;

  *proc1Ptr = dictionary (sym1);

  *proc2Ptr = dictionary (sym2);

  return TCL_OK;

}

/*

 *------------------------------------------------------------------------

 *

 * FindLibraries --

 *

 *      Find the libraries needed to link a load module at run time.

 *

 * Results:

 *      A standard Tcl completion code.  If an error occurs,

 *      an error message is left in interp->result.  The -l and -L flags

 *      are concatenated onto the dynamic string `buf'.

 *

 *------------------------------------------------------------------------

 */

static int

FindLibraries (interp, fileName, buf)

     Tcl_Interp * interp;       /* Used for error reporting */

     char * fileName;           /* Name of the load module */

     Tcl_DString * buf;         /* Buffer where the -l an -L flags */

{

  FILE * f;                     /* The load module */

  int c;                        /* Byte from the load module */

  char * p;

  /* Open the load module */

  if ((f = fopen (fileName, "rb")) == NULL) {

    Tcl_AppendResult (interp, "couldn't open \"", fileName, "\": ",

                      Tcl_PosixError (interp), (char *) NULL);

    return TCL_ERROR;

  }

  /* Search for the library list in the load module */

  p = "@LIBS: ";

  while (*p != '\0' && (c = getc (f)) != EOF) {

    if (c == *p) {

      ++p;

    }

    else {

      p = "@LIBS: ";

      if (c == *p) {

        ++p;

      }

    }

  }

  /* No library list -- this must be an ill-formed module */

  if (c == EOF) {

    Tcl_AppendResult (interp, "File \"", fileName,

                      "\" is not a Tcl load module.", (char *) NULL);

    (void) fclose (f);

    return TCL_ERROR;

  }

  /* Accumulate the library list */

  while ((c = getc (f)) != '\0' && c != EOF) {

    char cc = c;

    Tcl_DStringAppend (buf, &cc, 1);

  }

  (void) fclose (f);

  if (c == EOF) {

    Tcl_AppendResult (interp, "Library directory in \"", fileName,

                      "\" ends prematurely.", (char *) NULL);

    return TCL_ERROR;

  }

  return TCL_OK;

}

/*

 *------------------------------------------------------------------------

 *

 * UnlinkSymbolTable --

 *

 *      Remove the symbol table file from the last dynamic link.

 *

 * Results:

 *      None.

 *

 * Side effects:

 *      The symbol table file from the last dynamic link is removed.

 *      This function is called when (a) a new symbol table is present

 *      because another dynamic link is complete, or (b) the process

 *      is exiting.

 *------------------------------------------------------------------------

 */

static void

UnlinkSymbolTable ()

{

  (void) unlink (SymbolTableFile);

  ckfree (SymbolTableFile);

  SymbolTableFile = NULL;

}

/*

 *----------------------------------------------------------------------

 *

 * TclGuessPackageName --

 *

 *      If the "load" command is invoked without providing a package

 *      name, this procedure is invoked to try to figure it out.

 *

 * Results:

 *      Always returns 0 to indicate that we couldn't figure out a

 *      package name;  generic code will then try to guess the package

 *      from the file name.  A return value of 1 would have meant that

 *      we figured out the package name and put it in bufPtr.

 *

 * Side effects:

 *      None.

 *

 *----------------------------------------------------------------------

 */

int

TclGuessPackageName(fileName, bufPtr)

    char *fileName;             /* Name of file containing package (already

                                 * translated to local form if needed). */

    Tcl_DString *bufPtr;        /* Initialized empty dstring.  Append

                                 * package name to this if possible. */

{

    char *p, *q, *r;

    if (q = strrchr(fileName,'/')) {

        q++;

    } else {

        q = fileName;

    }

    if (!strncmp(q,"lib",3)) {

        q+=3;

    }

    p = q;

    while ((*p) && (*p != '.') && ((*p<'0') || (*p>'9'))) {

        p++;

    }

    if ((p>q+2) && !strncmp(p-2,"_G0.",4)) {

        p-=2;

    }

    if (p<q) {

        return 0;

    }

    Tcl_DStringAppend(bufPtr,q, p-q);

    r = Tcl_DStringValue(bufPtr);

    r += strlen(r) - (p-q);

    if (islower(UCHAR(*r))) {

        *r = (char) toupper(UCHAR(*r));

    }

    while (*(++r)) {

        if (isupper(UCHAR(*r))) {

            *r = (char) tolower(UCHAR(*r));

        }

    }

    return 1;

}