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+/*
+ * 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.
+ *
+ * SCCS: @(#) tclLoadAout.c 1.9 97/02/22 14:05:01
+ */
+
+#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;
+}