/*
* 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;
}