Added new functions to look up function symbols in dynamic libraries.

Bugzilla #27175.

nsprpub/pr/include/prlink.h

@@ -174,6 +174,17 @@ NSPR_API(PRStatus) PR_UnloadLibrary(PRLibrary *lib);
 */
 NSPR_API(void*) PR_FindSymbol(PRLibrary *lib, const char *name);
 
+/*
+** Similar to PR_FindSymbol, except that the return value is a pointer to
+** a function, and not a pointer to void. Casting between a data pointer
+** and a function pointer is not portable according to the C standard.
+** Any function pointer can be cast to any other function pointer.
+**
+** This function does not modify the reference count of the library.
+*/
+typedef void (*PRFuncPtr)(void);
+NSPR_API(PRFuncPtr) PR_FindFunctionSymbol(PRLibrary *lib, const char *name);
+
 /*
 ** Finds a symbol in one of the currently loaded libraries. Given the
 ** name of a procedure, return the address of the function that
@@ -187,6 +198,17 @@ NSPR_API(void*) PR_FindSymbol(PRLibrary *lib, const char *name);
 NSPR_API(void*) PR_FindSymbolAndLibrary(const char *name,
 						      PRLibrary* *lib);
 
+/*
+** Similar to PR_FindSymbolAndLibrary, except that the return value is
+** a pointer to a function, and not a pointer to void. Casting between a
+** data pointer and a function pointer is not portable according to the C
+** standard. Any function pointer can be cast to any other function pointer.
+**
+** This increments the reference count of the library.
+*/
+NSPR_API(PRFuncPtr) PR_FindFunctionSymbolAndLibrary(const char *name,
+						      PRLibrary* *lib);
+
 /*
 ** Register a static link table with the runtime under the name
 ** "name". The symbols present in the static link table will be made

nsprpub/pr/src/linking/prlink.c

@@ -1025,16 +1025,16 @@ done:
     return status;
 }
 
-static void* 
+static PRFuncPtr
 pr_FindSymbolInLib(PRLibrary *lm, const char *name)
 {
-    void *f = NULL;
+    PRFuncPtr f = NULL;
 
     if (lm->staticTable != NULL) {
     const PRStaticLinkTable* tp;
     for (tp = lm->staticTable; tp->name; tp++) {
         if (strcmp(name, tp->name) == 0) {
-        return (void*) tp->fp;
+        return (PRFuncPtr) tp->fp;
         }
     }
         /* 
@@ -1043,7 +1043,7 @@ pr_FindSymbolInLib(PRLibrary *lm, const char *name)
         */
 #if !defined(WIN16) && !defined(XP_BEOS)
         PR_SetError(PR_FIND_SYMBOL_ERROR, 0);
-        return (void*)NULL;
+        return (PRFuncPtr)NULL;
 #endif
     }
     
@@ -1052,7 +1052,7 @@ pr_FindSymbolInLib(PRLibrary *lm, const char *name)
 #endif  /* XP_OS2 */
 
 #if defined(WIN32) || defined(WIN16)
-    f = GetProcAddress(lm->dlh, name);
+    f = (PRFuncPtr) GetProcAddress(lm->dlh, name);
 #endif  /* WIN32 || WIN16 */
 
 #ifdef XP_MAC
@@ -1063,12 +1063,13 @@ pr_FindSymbolInLib(PRLibrary *lm, const char *name)
             
         PStrFromCStr(name, pName);    
         
-        f = (NSFindSymbol(lm->dlh, pName, &symAddr, &symClass) == noErr) ? symAddr : NULL;
+        f = (PRFuncPtr) (NSFindSymbol(lm->dlh, pName, &symAddr, &symClass)
+										== noErr) ? symAddr : NULL;
     }
 #endif /* XP_MAC */
 
 #ifdef XP_BEOS
-    if( B_NO_ERROR != get_image_symbol( (image_id)lm->dlh, name, B_SYMBOL_TYPE_TEXT, &f ) ) {
+    if( B_NO_ERROR != get_image_symbol( (image_id)lm->dlh, name, B_SYMBOL_TYPE_TEXT, (void *) &f ) ) {
 
 	f = NULL;
     }
@@ -1077,9 +1078,9 @@ pr_FindSymbolInLib(PRLibrary *lm, const char *name)
 #ifdef XP_UNIX
 #ifdef HAVE_DLL
 #ifdef USE_DLFCN
-    f = dlsym(lm->dlh, name);
+    f = (PRFuncPtr) dlsym(lm->dlh, name);
 #elif defined(USE_HPSHL)
-    if (shl_findsym(&lm->dlh, name, TYPE_PROCEDURE, &f) == -1) {
+    if (shl_findsym(&lm->dlh, name, TYPE_PROCEDURE, (void *) &f) == -1) {
         f = NULL;
     }
 #elif defined(USE_MACH_DYLD)
@@ -1087,7 +1088,7 @@ pr_FindSymbolInLib(PRLibrary *lm, const char *name)
         NSSymbol symbol;
         symbol = NSLookupSymbolInModule(lm->dlh, name);
         if (symbol != NULL)
-            f = NSAddressOfSymbol(symbol);
+            f = (PRFuncPtr) NSAddressOfSymbol(symbol);
         else
             f = NULL;
     }
@@ -1107,7 +1108,16 @@ pr_FindSymbolInLib(PRLibrary *lm, const char *name)
 PR_IMPLEMENT(void*) 
 PR_FindSymbol(PRLibrary *lib, const char *raw_name)
 {
-    void *f = NULL;
+    return ((void *) PR_FindFunctionSymbol(lib, raw_name));
+}
+
+/*
+** Return the address of the function 'raw_name' in the library 'lib'
+*/
+PR_IMPLEMENT(PRFuncPtr) 
+PR_FindFunctionSymbol(PRLibrary *lib, const char *raw_name)
+{
+    PRFuncPtr f = NULL;
 #if defined(NEED_LEADING_UNDERSCORE)
     char *name;
 #else
@@ -1145,7 +1155,13 @@ PR_FindSymbol(PRLibrary *lib, const char *raw_name)
 PR_IMPLEMENT(void*) 
 PR_FindSymbolAndLibrary(const char *raw_name, PRLibrary* *lib)
 {
-    void *f = NULL;
+	return ((void *) PR_FindFunctionSymbolAndLibrary(raw_name, lib));
+}
+
+PR_IMPLEMENT(PRFuncPtr) 
+PR_FindFunctionSymbolAndLibrary(const char *raw_name, PRLibrary* *lib)
+{
+    PRFuncPtr f = NULL;
 #if defined(NEED_LEADING_UNDERSCORE)
     char *name;
 #else

nsprpub/pr/tests/dlltest.c

@@ -87,7 +87,7 @@ int main(int argc, char** argv)
         if (!debug_mode) failed_already=1;
     }
     getFcn = (GetFcnType) PR_FindSymbol(lib, "My_GetValue");
-    setFcn = (SetFcnType) PR_FindSymbol(lib, "My_SetValue");
+    setFcn = (SetFcnType) PR_FindFunctionSymbol(lib, "My_SetValue");
     (*setFcn)(888);
     value = (*getFcn)();
     if (value != 888) {
@@ -136,7 +136,7 @@ int main(int argc, char** argv)
         if (!debug_mode) failed_already=1;
         goto exit_now;
     }
-    getFcn = (GetFcnType) PR_FindSymbol(lib2, "My_GetValue");
+    getFcn = (GetFcnType) PR_FindFunctionSymbol(lib2, "My_GetValue");
     setFcn = (SetFcnType) PR_FindSymbol(lib2, "My_SetValue");
     (*setFcn)(666);
     value = (*getFcn)();
@@ -158,7 +158,7 @@ int main(int argc, char** argv)
         if (!debug_mode) failed_already=1;
         goto exit_now;
     }
-    getFcn = (GetFcnType) PR_FindSymbolAndLibrary("My_GetValue", &lib2);
+    getFcn = (GetFcnType) PR_FindFunctionSymbolAndLibrary("My_GetValue", &lib2);
     if (NULL != getFcn) {
         fprintf(stderr, "Test 4 failed: how can we find a symbol "
             "in an already unloaded library?\n");