Use musl's stub implementation of dladdr. NFC (#19319)

Author: sbc100

ChangeLog.md

@@ -20,6 +20,8 @@ See docs/process.md for more on how version tagging works.
 
 3.1.38 (in development)
 -----------------------
+- The `dladdr` function will now always return an error rather than filling in
+  dummy values. (#19319)
 - The restriction preventing the use of dynamic linking in combination with
   `-sDYNAMIC_EXECUTION=0` was removed.  This restriction was being enforced
   unnecessarily since dynamic linking has not depended on `eval()` for a while

src/library_dylink.js

@@ -281,7 +281,6 @@ var LibraryDylink = {
   dlopen__deps: [function() { error(dlopenMissingError); }],
   emscripten_dlopen__deps: [function() { error(dlopenMissingError); }],
   __dlsym__deps: [function() { error(dlopenMissingError); }],
-  dladdr__deps: [function() { error(dlopenMissingError); }],
 #else
   $dlopenMissingError: `= ${dlopenMissingError}`,
   _dlopen_js__deps: ['$dlopenMissingError'],
@@ -291,7 +290,6 @@ var LibraryDylink = {
   dlopen__deps: ['$dlopenMissingError'],
   emscripten_dlopen__deps: ['$dlopenMissingError'],
   __dlsym__deps: ['$dlopenMissingError'],
-  dladdr__deps: ['$dlopenMissingError'],
 #endif
   _dlopen_js: function(handle) {
     abort(dlopenMissingError);
@@ -314,9 +312,6 @@ var LibraryDylink = {
   __dlsym: function(handle, symbol) {
     abort(dlopenMissingError);
   },
-  dladdr: function() {
-    abort(dlopenMissingError);
-  },
 #else // MAIN_MODULE != 0
   // dynamic linker/loader (a-la ld.so on ELF systems)
   $LDSO__deps: ['$newDSO'],

src/library_sigs.js

@@ -461,7 +461,6 @@ sigs = {
   boxRGBA__sig: 'ipiiiiiiii',
   clock_res_get__sig: 'iip',
   clock_time_get__sig: 'iijp',
-  dladdr__sig: 'ipp',
   dlopen__sig: 'ppi',
   eglBindAPI__sig: 'ii',
   eglChooseConfig__sig: 'ipppip',

system/lib/libc/dynlink.c

@@ -584,13 +584,3 @@ void* __dlsym(void* restrict p, const char* restrict s, void* restrict ra) {
   do_write_unlock();
   return res;
 }
-
-int dladdr(const void* addr, Dl_info* info) {
-  // report all function pointers as coming from this program itself XXX not
-  // really correct in any way
-  info->dli_fname = "unknown";
-  info->dli_fbase = NULL;
-  info->dli_sname = NULL;
-  info->dli_saddr = NULL;
-  return 1;
-}

test/test_core.py

@@ -3671,17 +3671,12 @@ def test_dlfcn_info(self):
         /* Verify that we don't corrupt func_ptr when calling dladdr.  */
         Dl_info info;
         memset(&info, 0, sizeof(info));
-        dladdr(func_ptr, &info);
+        int rtn = dladdr(func_ptr, &info);
+        assert(rtn == 0);
 
         assert(func_ptr != NULL);
         assert(func_ptr(0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0) == 13);
 
-        /* Verify something useful lives in info.  */
-        assert(info.dli_fname != NULL);
-        assert(info.dli_fbase == NULL);
-        assert(info.dli_sname == NULL);
-        assert(info.dli_saddr == NULL);
-
         puts("success");
 
         return 0;

test/test_other.py

@@ -12227,17 +12227,19 @@ def test_unimplemented_syscalls_dlopen(self):
 
   def test_unimplemented_syscalls_dladdr(self):
     create_file('main.c', '''
+    #include <assert.h>
     #include <dlfcn.h>
 
     int main() {
-      dladdr(0, 0);
+      Dl_info info;
+      int rtn = dladdr(&main, &info);
+      assert(rtn == 0);
       return 0;
     }
     ''')
 
-    self.run_process([EMCC, 'main.c'])
-    err = self.run_js('a.out.js', assert_returncode=NON_ZERO)
-    self.assertContained('Aborted(To use dlopen, you need enable dynamic linking, see https://emscripten.org/docs/compiling/Dynamic-Linking.html)', err)
+    self.do_runf('main.c')
+    self.do_runf('main.c', emcc_args=['-sMAIN_MODULE=2'])
 
   @requires_v8
   def test_missing_shell_support(self):

tools/system_libs.py

@@ -1173,7 +1173,7 @@ def get_files(self):
 
     libc_files += files_in_path(
         path='system/lib/libc/musl/src/ldso',
-        filenames=['dlerror.c', 'dlsym.c', 'dlclose.c'])
+        filenames=['dladdr.c', 'dlerror.c', 'dlsym.c', 'dlclose.c'])
 
     libc_files += files_in_path(
         path='system/lib/libc/musl/src/signal',