libltdl and Guile

[Marius Vollmer]

Hi,

Guile uses libtldl to do its dynamic linking and we decided to ship
our own copy of it (suitably renamed) since we found that libltdl
contained some showstopper bugs and we wanted be able to fix them
quickly without having to wait for a libtool releases and also to be
sure that people use the right version of libltdl.  Please don't think
of this as a fork; we hope that this way, we can better help to
improve libltdl in general.

And so here is the first patch that we use (it's against 1.4.3).  What
do you think?

2002-10-04  Rob Browning  <address@hidden>

        * ltdl.c: (memcpy): coerce ptrs to (char *) before copying
        characters through them -- I can't recall for sure, but I
        believe this was causing an overrun error at times.
        (realloc): Remove custom realloc. (#define rpl_realloc realloc)
        and comment out later code for custom realloc.  You can't define
        your own malloc unless you know enough about the malloc in use to
        be able to tell how big the src ptr is.  The disabled code
        incorrectly used the *destination* ptr to decide how much to copy.
        This sometimes results in out-of-bound accesses which cause
        segfaults.  This is a quick hack for now; we may want something
        cleaner later.
        (tryall_dlopen_module): check to be sure (dirname_len > 0) before
        testing first character against '/'.
        (try_dlopen): check for feof(file) in read loop -- otherwise
        infloop?
        (LT_EOS_CHAR): moved here from guile-ltdl.h.

2002-10-04  Marius Vollmer  <address@hidden>

        * raw-ltdl.c: (try_dlopen): Set newhandle to null when
        try_all_dlopen failed.
        (scm_lt_dlopenext): Reverse test of "file_not_found()".
        Previously, we would stop searching when the file wasn't found
        yet, while we should continue in that case.

--- ltdl.h      2002-10-25 17:55:30.000000000 +0200
+++ raw-ltdl.guilemod.h 2002-10-26 16:32:35.000000000 +0200
@@ -1,5 +1,5 @@
 /* ltdl.h -- generic dlopen functions
-   Copyright (C) 1998-2000 Free Software Foundation, Inc.
+   Copyright (C) 1998-2000, 2002 Free Software Foundation, Inc.
    Originally by Thomas Tanner <address@hidden>
    This file is part of GNU Libtool.
 
@@ -28,15 +28,13 @@
 #ifndef LTDL_H
 #define LTDL_H 1
 
 #include <sys/types.h>         /* for size_t declaration */
 
 
 /* --- MACROS FOR PORTABILITY --- */
 
-
-/* Saves on those hard to debug '\0' typos....  */
-#define LT_EOS_CHAR    '\0'
-
 /* LTDL_BEGIN_C_DECLS should be used at the beginning of your declarations,
    so that C++ compilers don't mangle their names.  Use LTDL_END_C_DECLS at
    the end of C declarations. */
--- ltdl.c      2002-10-25 17:55:30.000000000 +0200
+++ raw-ltdl.guilemod.c 2002-10-26 16:32:35.000000000 +0200
@@ -1,5 +1,5 @@
 /* ltdl.c -- system independent dlopen wrapper
-   Copyright (C) 1998, 1999, 2000 Free Software Foundation, Inc.
+   Copyright (C) 1998, 1999, 2000, 2002 Free Software Foundation, Inc.
    Originally by Thomas Tanner <address@hidden>
    This file is part of GNU Libtool.
 
@@ -26,7 +26,7 @@
 */
 
 #if HAVE_CONFIG_H
 #  include <config.h>
 #endif
 
 #if HAVE_UNISTD_H
@@ -92,13 +92,15 @@
 #  define assert(arg)  ((void) 0)
 #endif
 
 #include "ltdl.h"
 
 #if WITH_DMALLOC
 #  include <dmalloc.h>
 #endif
 
 
+/* Saves on those hard to debug '\0' typos....  */
+#define LT_EOS_CHAR    '\0'
 
 
 /* --- WINDOWS SUPPORT --- */
@@ -158,7 +160,7 @@
 static lt_ptr lt_emalloc       LT_PARAMS((size_t size));
 static lt_ptr lt_erealloc      LT_PARAMS((lt_ptr addr, size_t size));
 
-static lt_ptr rpl_realloc      LT_PARAMS((lt_ptr ptr, size_t size));
+#define rpl_realloc realloc
 
 /* These are the pointers that can be changed by the caller:  */
 LT_GLOBAL_DATA lt_ptr (*lt_dlmalloc)   LT_PARAMS((size_t size))
@@ -333,7 +335,7 @@
 
   for (i = 0; i < size; ++i)
     {
-      dest[i] = src[i];
+      ((char *) dest)[i] = ((char *) src)[i];
     }
 
   return dest;
@@ -379,8 +381,14 @@
    Instead implement our own version (with known boundary conditions)
    using lt_dlmalloc and lt_dlfree. */
 
-#undef realloc
-#define realloc rpl_realloc
+
+#if 0
+
+  /* You can't (re)define realloc unless you also (re)define malloc.
+     Right now, this code uses the size of the *destination* to decide
+     how much to copy.  That's not right, but you can't know the size
+     of the source unless you know enough about, or wrote malloc.  So
+     this code is disabled... */
 
 static lt_ptr
 realloc (ptr, size)
@@ -419,6 +427,8 @@
     }
 }
 
+#endif
+
 
 #if ! HAVE_ARGZ_APPEND
 #  define argz_append rpl_argz_append
@@ -809,7 +819,6 @@
 
 /* --- ERROR HANDLING --- */
 
-
 static const char    **user_error_strings      = NULL;
 static int             errorcount              = LT_ERROR_MAX;
 
@@ -1976,8 +1985,9 @@
   assert (strchr (dirname, LT_DIRSEP_CHAR) == NULL);
 #endif
 
-  if (dirname[dirname_len -1] == '/')
-    --dirname_len;
+  if (dirname_len > 0)
+    if (dirname[dirname_len -1] == '/')
+      --dirname_len;
   filename_len = dirname_len + 1 + LT_STRLEN (dlname);
 
   /* Allocate memory, and combine DIRNAME and MODULENAME into it.
@@ -2721,7 +2731,7 @@
 
          /* Handle the case where we occasionally need to read a line
             that is longer than the initial buffer size.  */
-         while (line[LT_STRLEN(line) -1] != '\n')
+         while ((line[LT_STRLEN(line) -1] != '\n') && (!feof (file)))
            {
              line = LT_DLREALLOC (char, line, line_len *2);
              if (!fgets (&line[line_len -1], (int) line_len +1, file))
@@ -2987,7 +2997,7 @@
      failed, it is better to return an error message here than to
      report FILE_NOT_FOUND when the alternatives (foo.so etc) are not
      in the module search path.  */
-  if (handle || ((errors > 0) && file_not_found ()))
+  if (handle || ((errors > 0) && !file_not_found ()))
     {
       LT_DLFREE (tmp);
       return handle;
@@ -3014,7 +3024,7 @@
 
   /* As before, if the file was found but loading failed, return now
      with the current error message.  */
-  if (handle || ((errors > 0) && file_not_found ()))
+  if (handle || ((errors > 0) && !file_not_found ()))
     {
       LT_DLFREE (tmp);
       return handle;