Initial revision

1 files changed, 470 insertions, 0 deletions

diff --git a/unix/tclLoadAout.c b/unix/tclLoadAout.c
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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;
+}