This changes the behaviour of the DSO mechanism for determining an

appropriate filename translation on the host system. Apart from this point,
users should also note that there's a slight change in the API functions
too. The DSO now contains its own to-be-converted filename
("dso->filename"), and at the time the DSO loads the "dso->loaded_filename"
value is set to the translated form. As such, this also provides an impicit
way of determining if the DSO is currently loaded or not. Except, perhaps,
VMS .... :-)

The various DSO_METHODs have been updated for this mechanism except VMS
which is deliberately broken for now, Richard is going to look at how to
fit it in (the source comments in there explain "the issue").

Basically, the new callback scheme allows the filename conversion to
(a) be turned off altogether through the use of the
    DSO_FLAG_NO_NAME_TRANSLATION flag,
(b) be handled in the default way using the default DSO_METHOD's converter
(c) overriden per-DSO by setting the override callback
(d) a mix of (b) and (c) - eg. implement an override callback that;
    (i) checks if we're win32 "if(strstr(dso->meth->name, "win32"))..."
        and if so, convert "blah" into "blah32.dll" (the default is
	otherwise to make it "blah.dll").
    (ii) default to the normal behaviour - eg. we're not on win32, so
         finish with (return dso->meth->dso_name_converter(dso,NULL)).
(e) be retried a number of times by writing a new DSO_METHOD where the
    "dso_load()" handler will call the converter repeatedly. Then the
    custom converter could use state information in the DSO to suggest
    different conversions or paths each time it is invoked.

1 files changed, 85 insertions, 13 deletions

diff --git a/crypto/dso/dso.h b/crypto/dso/dso.h
index 2770e3b763..add6858de8 100644
--- a/crypto/dso/dso.h
+++ b/crypto/dso/dso.h
@@ -70,15 +70,18 @@ extern "C" {
 #define DSO_CTRL_SET_FLAGS	2
 #define DSO_CTRL_OR_FLAGS	3
 
-/* These flags control the translation of file-names from canonical to
- * native. Eg. in the CryptoSwift support, the "dl" and "dlfcn"
- * methods will translate "swift" -> "libswift.so" whereas the "win32"
- * method will translate "swift" -> "swift.dll". NB: Until I can figure
- * out how to be more "conventional" with this, the methods will only
- * honour this flag if it looks like it was passed a file without any
- * path and if the filename is small enough.
- */
-#define DSO_FLAG_NAME_TRANSLATION 0x01
+/* By default, DSO_load() will translate the provided filename into a form
+ * typical for the platform (more specifically the DSO_METHOD) using the
+ * dso_name_converter function of the method. Eg. win32 will transform "blah"
+ * into "blah.dll", and dlfcn will transform it into "libblah.so". The
+ * behaviour can be overriden by setting the name_converter callback in the DSO
+ * object (using DSO_set_name_converter()). This callback could even utilise
+ * the DSO_METHOD's converter too if it only wants to override behaviour for
+ * one or two possible DSO methods. However, the following flag can be set in a
+ * DSO to prevent *any* native name-translation at all - eg. if the caller has
+ * prompted the user for a path to a driver library so the filename should be
+ * interpreted as-is. */
+#define DSO_FLAG_NO_NAME_TRANSLATION 0x01
 
 /* The following flag controls the translation of symbol names to upper
  * case.  This is currently only being implemented for OpenVMS.
@@ -90,11 +93,21 @@ typedef void (*DSO_FUNC_TYPE)(void);
 
 typedef struct dso_st DSO;
 
+/* The function prototype used for method functions (or caller-provided
+ * callbacks) that transform filenames. They are passed a DSO structure pointer
+ * (or NULL if they are to be used independantly of a DSO object) and a
+ * filename to transform. They should either return NULL (if there is an error
+ * condition) or a newly allocated string containing the transformed form that
+ * the caller will need to free with OPENSSL_free() when done. */
+typedef char* (*DSO_NAME_CONVERTER_FUNC)(DSO *, const char *);
+
 typedef struct dso_meth_st
 	{
 	const char *name;
-	/* Loads a shared library */
-	int (*dso_load)(DSO *dso, const char *filename);
+	/* Loads a shared library, NB: new DSO_METHODs must ensure that a
+	 * successful load populates the loaded_filename field, and likewise a
+	 * successful unload OPENSSL_frees and NULLs it out. */
+	int (*dso_load)(DSO *dso);
 	/* Unloads a shared library */
 	int (*dso_unload)(DSO *dso);
 	/* Binds a variable */
@@ -117,6 +130,9 @@ typedef struct dso_meth_st
 	/* The generic (yuck) "ctrl()" function. NB: Negative return
 	 * values (rather than zero) indicate errors. */
 	long (*dso_ctrl)(DSO *dso, int cmd, long larg, void *parg);
+	/* The default DSO_METHOD-specific function for converting filenames to
+	 * a canonical native form. */
+	DSO_NAME_CONVERTER_FUNC dso_name_converter;
 
 	/* [De]Initialisation handlers. */
 	int (*init)(DSO *dso);
@@ -140,6 +156,23 @@ struct dso_st
 	/* For use by applications etc ... use this for your bits'n'pieces,
 	 * don't touch meth_data! */
 	CRYPTO_EX_DATA ex_data;
+	/* If this callback function pointer is set to non-NULL, then it will
+	 * be used on DSO_load() in place of meth->dso_name_converter. NB: This
+	 * should normally set using DSO_set_name_converter(). */
+	DSO_NAME_CONVERTER_FUNC name_converter;
+	/* This is populated with (a copy of) the platform-independant
+	 * filename used for this DSO. */
+	char *filename;
+	/* This is populated with (a copy of) the translated filename by which
+	 * the DSO was actually loaded. It is NULL iff the DSO is not currently
+	 * loaded. NB: This is here because the filename translation process
+	 * may involve a callback being invoked more than once not only to
+	 * convert to a platform-specific form, but also to try different
+	 * filenames in the process of trying to perform a load. As such, this
+	 * variable can be used to indicate (a) whether this DSO structure
+	 * corresponds to a loaded library or not, and (b) the filename with
+	 * which it was actually loaded. */
+	char *loaded_filename;
 	};
 
 
@@ -149,8 +182,35 @@ int	DSO_free(DSO *dso);
 int	DSO_flags(DSO *dso);
 int	DSO_up(DSO *dso);
 long	DSO_ctrl(DSO *dso, int cmd, long larg, void *parg);
-
-void DSO_set_default_method(DSO_METHOD *meth);
+/* This function sets the DSO's name_converter callback. If it is non-NULL,
+ * then it will be used instead of the associated DSO_METHOD's function. If
+ * oldcb is non-NULL then it is set to the function pointer value being
+ * replaced. Return value is non-zero for success. */
+int	DSO_set_name_converter(DSO *dso, DSO_NAME_CONVERTER_FUNC cb,
+				DSO_NAME_CONVERTER_FUNC *oldcb);
+/* These functions can be used to get/set the platform-independant filename
+ * used for a DSO. NB: set will fail if the DSO is already loaded. */
+const char *DSO_get_filename(DSO *dso);
+int	DSO_set_filename(DSO *dso, const char *filename);
+/* This function will invoke the DSO's name_converter callback to translate a
+ * filename, or if the callback isn't set it will instead use the DSO_METHOD's
+ * converter. If "filename" is NULL, the "filename" in the DSO itself will be
+ * used. If the DSO_FLAG_NO_NAME_TRANSLATION flag is set, then the filename is
+ * simply duplicated. NB: This function is usually called from within a
+ * DSO_METHOD during the processing of a DSO_load() call, and is exposed so that
+ * caller-created DSO_METHODs can do the same thing. A non-NULL return value
+ * will need to be OPENSSL_free()'d. */
+char	*DSO_convert_filename(DSO *dso, const char *filename);
+/* If the DSO is currently loaded, this returns the filename that it was loaded
+ * under, otherwise it returns NULL. So it is also useful as a test as to
+ * whether the DSO is currently loaded. NB: This will not necessarily return
+ * the same value as DSO_convert_filename(dso, dso->filename), because the
+ * DSO_METHOD's load function may have tried a variety of filenames (with
+ * and/or without the aid of the converters) before settling on the one it
+ * actually loaded. */
+const char *DSO_get_loaded_filename(DSO *dso);
+
+void	DSO_set_default_method(DSO_METHOD *meth);
 DSO_METHOD *DSO_get_default_method(void);
 DSO_METHOD *DSO_get_method(DSO *dso);
 DSO_METHOD *DSO_set_method(DSO *dso, DSO_METHOD *meth);
@@ -207,17 +267,24 @@ void ERR_load_DSO_strings(void);
 #define DSO_F_DLFCN_BIND_FUNC				 100
 #define DSO_F_DLFCN_BIND_VAR				 101
 #define DSO_F_DLFCN_LOAD				 102
+#define DSO_F_DLFCN_NAME_CONVERTER			 123
 #define DSO_F_DLFCN_UNLOAD				 103
 #define DSO_F_DL_BIND_FUNC				 104
 #define DSO_F_DL_BIND_VAR				 105
 #define DSO_F_DL_LOAD					 106
+#define DSO_F_DL_NAME_CONVERTER				 124
 #define DSO_F_DL_UNLOAD					 107
 #define DSO_F_DSO_BIND_FUNC				 108
 #define DSO_F_DSO_BIND_VAR				 109
+#define DSO_F_DSO_CONVERT_FILENAME			 126
 #define DSO_F_DSO_CTRL					 110
 #define DSO_F_DSO_FREE					 111
+#define DSO_F_DSO_GET_FILENAME				 127
+#define DSO_F_DSO_GET_LOADED_FILENAME			 128
 #define DSO_F_DSO_LOAD					 112
 #define DSO_F_DSO_NEW_METHOD				 113
+#define DSO_F_DSO_SET_FILENAME				 129
+#define DSO_F_DSO_SET_NAME_CONVERTER			 122
 #define DSO_F_DSO_UP					 114
 #define DSO_F_VMS_BIND_VAR				 115
 #define DSO_F_VMS_LOAD					 116
@@ -225,14 +292,19 @@ void ERR_load_DSO_strings(void);
 #define DSO_F_WIN32_BIND_FUNC				 118
 #define DSO_F_WIN32_BIND_VAR				 119
 #define DSO_F_WIN32_LOAD				 120
+#define DSO_F_WIN32_NAME_CONVERTER			 125
 #define DSO_F_WIN32_UNLOAD				 121
 
 /* Reason codes. */
 #define DSO_R_CTRL_FAILED				 100
+#define DSO_R_DSO_ALREADY_LOADED			 110
 #define DSO_R_FILENAME_TOO_BIG				 101
 #define DSO_R_FINISH_FAILED				 102
 #define DSO_R_LOAD_FAILED				 103
+#define DSO_R_NAME_TRANSLATION_FAILED			 109
+#define DSO_R_NO_FILENAME				 111
 #define DSO_R_NULL_HANDLE				 104
+#define DSO_R_SET_FILENAME_FAILED			 112
 #define DSO_R_STACK_ERROR				 105
 #define DSO_R_SYM_FAILURE				 106
 #define DSO_R_UNLOAD_FAILED				 107