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Diffstat (limited to 'unix/tclLoadAout.c')
| -rw-r--r-- | unix/tclLoadAout.c | 470 |
1 files changed, 470 insertions, 0 deletions
diff --git a/unix/tclLoadAout.c b/unix/tclLoadAout.c new file mode 100644 index 0000000..ade7161 --- /dev/null +++ b/unix/tclLoadAout.c @@ -0,0 +1,470 @@ +/* + * 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; +} |