/* 

  * 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 1.14 2002/10/10 12:25:53 vincentdarley Exp $

  */

 #include "tclInt.h"

 #include <fcntl.h>

 #ifdef HAVE_EXEC_AOUT_H

 #   include <sys/exec_aout.h>

 #endif

 #ifdef HAVE_UNISTD_H

 #   include <unistd.h>

 #else

 #   include "../compat/unistd.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_ ((CONST char * symbol));

 /*

  * Prototypes for procedures referenced only in this file:

  */

 static int FindLibraries _ANSI_ARGS_((Tcl_Interp * interp, Tcl_Obj * pathPtr,

 				      Tcl_DString * buf));

 static void UnlinkSymbolTable _ANSI_ARGS_((void));

 /*

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

  *

  * TclpDlopen --

  *

  *	Dynamically loads a binary code file into memory and returns

  *	a handle to the new code.

  *

  * Results:

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

  *	message is left in the interp's result. 

  *

  * 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

 TclpDlopen(interp, pathPtr, loadHandle, unloadProcPtr)

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

     Tcl_Obj *pathPtr;		/* Name of the file containing the desired

 				 * code (UTF-8). */

     Tcl_LoadHandle *loadHandle;	/* Filled with token for dynamically loaded

 				 * file which will be passed back to 

 				 * (*unloadProcPtr)() to unload the file. */

     Tcl_FSUnloadFileProc **unloadProcPtr;	

 				/* Filled with address of Tcl_FSUnloadFileProc

 				 * function which should be used for

 				 * this file. */

 {

     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 */

     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(Tcl_GetString(pathPtr), &linkCommandBuf);

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

     Tcl_DStringAppend (&linkCommandBuf, inputSymbolTable, -1);

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

     Tcl_DStringAppend (&linkCommandBuf, Tcl_GetString(pathPtr), -1);

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

     if (FindLibraries (interp, pathPtr, &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.

      *

      * Note that this does not really work with large files (i.e. where

      * lseek64 exists and is different to lseek), but anyone trying to

      * dynamically load a binary that is larger than what can fit in

      * addressable memory is in trouble anyway...

      */

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

     status = lseek (relocatedFd,

 		    (off_t) N_TXTOFF (relocatedHead.ex_f, relocatedHead.ex_o),

 		    SEEK_SET);

 #else

     status = lseek (relocatedFd, (off_t) 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);

     *loadHandle = startAddress;

     return TCL_OK;

 }

 /*

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

  *

  * TclpFindSymbol --

  *

  *	Looks up a symbol, by name, through a handle associated with

  *	a previously loaded piece of code (shared library).

  *

  * Results:

  *	Returns a pointer to the function associated with 'symbol' if

  *	it is found.  Otherwise returns NULL and may leave an error

  *	message in the interp's result.

  *

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

  */

 Tcl_PackageInitProc*

 TclpFindSymbol(interp, loadHandle, symbol) 

     Tcl_Interp *interp;

     Tcl_LoadHandle loadHandle;

     CONST char *symbol;

 {

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

     DictFn dictionary = (DictFn) loadHandle;

     return (Tcl_PackageInitProc*) dictionary(sym1);

 }

 /*

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

  *

  * 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 the interp's result.  The -l and -L

  *	flags are concatenated onto the dynamic string `buf'.

  *

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

  */

 static int

 FindLibraries (interp, pathPtr, buf)

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

     Tcl_Obj * pathPtr;		/* Name of the load module */

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

 {

     FILE * f;			/* The load module */

     int c = 0;			/* Byte from the load module */

     char * p;

     CONST char *native;

     char *fileName = Tcl_GetString(pathPtr);

     /* Open the load module */

     native = Tcl_FSGetNativePath(pathPtr);

     f = fopen(native, "rb");				/* INTL: Native. */

     if (f == 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;

 }

 /*

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

  *

  * TclpUnloadFile --

  *

  *	Unloads a dynamically loaded binary code file from memory.

  *	Code pointers in the formerly loaded file are no longer valid

  *	after calling this function.

  *

  * Results:

  *	None.

  *

  * Side effects:

  *	Does nothing.  Can anything be done?

  *

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

  */

 void

 TclpUnloadFile(loadHandle)

     Tcl_LoadHandle loadHandle;	/* loadHandle returned by a previous call

 				 * to TclpDlopen().  The loadHandle is 

 				 * a token that represents the loaded 

 				 * file. */

 {

 }

 /*

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

  *

  * 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)

     CONST 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. */

 {

     CONST char *p, *q;

     char *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);

     /*

      * Capitalize the string and then recompute the length.

      */

     Tcl_UtfToTitle(r);

     Tcl_DStringSetLength(bufPtr, strlen(Tcl_DStringValue(bufPtr)));

     return 1;

 }