/* * 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 1.15 2005/07/19 13:37:18 dkf Exp $ */ #include "tclInt.h" #include #ifdef HAVE_EXEC_AOUT_H # include #endif #ifdef HAVE_UNISTD_H # include #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 #endif #ifdef USE_A_OUT_H #include #endif #ifdef USE_SYS_EXEC_AOUT_H #include #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