update from tobold

cipher/dynload.c

@@ -18,13 +18,194 @@
  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
  */
 
-
-
 #include <config.h>
 #include <stdio.h>
 #include <stdlib.h>
-
+#include <string.h>
+#include <dlfcn.h>
+#include "util.h"
+#include "cipher.h"
 #include "dynload.h"
 
+typedef struct ext_list {
+    struct ext_list *next;
+    void *handle; /* handle from dlopen() */
+    int  failed;  /* already tried but failed */
+    void * (*enumfunc)(int, int*, int*, int*);
+    char name[1];
+} *EXTLIST;
+
+static EXTLIST extensions;
+
+typedef struct {
+    EXTLIST r;
+    int seq1;
+    int seq2;
+    void *sym;
+} ENUMCONTEXT;
+
+/****************
+ * Register an extension module.  The last registered module will
+ * be loaded first.
+ */
+void
+register_cipher_extension( const char *fname )
+{
+    EXTLIST r, el;
+
+    if( *fname != '/' ) { /* do tilde expansion etc */
+	char *p ;
+
+	if( strchr(fname, '/') )
+	    p = make_filename(fname, NULL);
+	else
+	    p = make_filename(GNUPG_LIBDIR, fname, NULL);
+	el = m_alloc_clear( sizeof *el + strlen(p) );
+	strcpy(el->name, p );
+	m_free(p);
+    }
+    else {
+	el = m_alloc_clear( sizeof *el + strlen(fname) );
+	strcpy(el->name, fname );
+    }
+    /* check that it is not already registered */
+    for(r = extensions; r; r = r->next )
+	if( !compare_filenames(r->name, el->name) ) {
+	    log_debug("extension '%s' already registered\n", el->name );
+	    m_free(el);
+	    return;
+	}
+    log_debug("extension '%s' registered\n", el->name );
+    /* and register */
+    el->next = extensions;
+    extensions = el;
+}
 
 
+static int
+load_extension( EXTLIST el )
+{
+    char **name;
+    void *sym;
+    const char *err;
+    int seq = 0;
+    int class, vers;
+
+    el->handle = dlopen(el->name, RTLD_LAZY);
+    if( !el->handle ) {
+	log_error("%s: error loading extension: %s\n", el->name, dlerror() );
+	goto failure;
+    }
+    name = (char**)dlsym(el->handle, "gnupgext_version");
+    if( (err=dlerror()) ) {
+	log_error("%s: not a gnupg extension: %s\n", el->name, err );
+	goto failure;
+    }
+
+    log_info("%s: version '%s'\n", el->name, *name );
+
+    sym = dlsym(el->handle, "gnupgext_enum_func");
+    if( (err=dlerror()) ) {
+	log_error("%s: invalid gnupg extension: %s\n", el->name, err );
+	goto failure;
+    }
+    el->enumfunc = (void *(*)(int,int*,int*,int*))sym;
+
+    /* list the contents of the module */
+    while( (sym = (*el->enumfunc)(0, &seq, &class, &vers)) ) {
+	if( vers != 1 ) {
+	    log_error("%s: ignoring func with version %d\n", el->name, vers);
+	    continue;
+	}
+	switch( class ) {
+	  case 11:
+	  case 21:
+	  case 31:
+	    log_info("%s: provides %s algorithm %d\n", el->name,
+			    class == 11? "md"     :
+			    class == 21? "cipher" : "pubkey",
+						   *(int*)sym);
+	    break;
+	  default:
+	    log_debug("%s: skipping class %d\n", el->name, class);
+	}
+    }
+    return 0;
+
+  failure:
+    if( el->handle ) {
+	dlclose(el->handle);
+	el->handle = NULL;
+    }
+    el->failed = 1;
+    return -1;
+}
+
+
+
+const char *
+enum_gnupgext_ciphers( void **enum_context, int *algo,
+		       size_t *keylen, size_t *blocksize, size_t *contextsize,
+		       void (**setkey)( void *c, byte *key, unsigned keylen ),
+		       void (**encrypt)( void *c, byte *outbuf, byte *inbuf ),
+		       void (**decrypt)( void *c, byte *outbuf, byte *inbuf )
+		     )
+{
+    EXTLIST r;
+    ENUMCONTEXT *ctx;
+    const char * (*finfo)(int, size_t*, size_t*, size_t*,
+			  void (**)( void *, byte *, unsigned),
+			  void (**)( void *, byte *, byte *),
+			  void (**)( void *, byte *, byte *));
+
+    if( !*enum_context ) { /* init context */
+	ctx = m_alloc_clear( sizeof( *ctx ) );
+	ctx->r = extensions;
+	*enum_context = ctx;
+    }
+    else if( !algo ) { /* release the context */
+	m_free(*enum_context);
+	*enum_context = NULL;
+	return NULL;
+    }
+    else
+	ctx = *enum_context;
+
+    for( r = ctx->r; r; r = r->next )  {
+	int class, vers;
+
+	if( r->failed )
+	    continue;
+	if( !r->handle && load_extension(r) )
+	    continue;
+	/* get a cipher info function */
+	if( ctx->sym )
+	    goto inner_loop;
+	while( (ctx->sym = (*r->enumfunc)(20, &ctx->seq1, &class, &vers)) ) {
+	    void *sym;
+	    /* must check class because enumfunc may be wrong coded */
+	    if( vers != 1 || class != 20 )
+		continue;
+	  inner_loop:
+	    finfo = ctx->sym;
+	    while( (sym = (*r->enumfunc)(21, &ctx->seq2, &class, &vers)) ) {
+		const char *algname;
+		if( vers != 1 || class != 21 )
+		    continue;
+		*algo = *(int*)sym;
+		algname = (*finfo)( *algo, keylen, blocksize, contextsize,
+				    setkey, encrypt, decrypt );
+		log_debug("found algo %d (%s)\n", *algo, algname );
+		if( algname ) {
+		    ctx->r = r;
+		    return algname;
+		}
+	    }
+	    ctx->seq2 = 0;
+	}
+	ctx->seq1 = 0;
+    }
+    ctx->r = r;
+    return NULL;
+}
+