# Enhance emacs to also look for the pdmp file in PATH_EXEC using the
# name seen in realpath(argv[0]). Emacs is typically run via the mediated
# /usr/bin/emacs symlink, which points at one of the emacs variants
# (emacs-gtk, emacs-x, emacs-nox). Adding the check for the name found
# via realpath() allows the actual emacs binary to find its pdump file.
#
--- emacs-27.2.orig/src/emacs.c	2021-01-28 10:52:38.000000000 +0000
+++ emacs-27.2/src/emacs.c	2021-04-14 13:12:46.732537010 +0000
@@ -766,6 +766,55 @@
 #endif	/* !WINDOWSNT */
 }
 
+/*
+ * basename() for pdump paths
+ */
+static char *
+load_pdump_basename(char *path)
+{
+  char *p, *last_sep = NULL;
+
+  for (p = path; *p; p++)
+    {
+      if (IS_DIRECTORY_SEP (*p))
+	 last_sep = p;
+    }
+
+    return last_sep ? last_sep + 1 : path;
+}
+
+/*
+ * Given a basename for the running emacs, attempt to open
+ * the corresponding pdump file in the directory given by path.
+ */
+static int
+load_pdump_from_path(const char *path, const char *name, const char *suffix,
+		     char **dump_file, ptrdiff_t *bufsize)
+{
+  ptrdiff_t needed = (strlen (path)
+		      + 1
+		      + strlen (name)
+		      + strlen (suffix)
+		      + 1);
+  if (*bufsize < needed)
+    {
+      xfree (*dump_file);
+      *dump_file = xmalloc (needed);
+      *bufsize = needed;
+    }
+#ifdef DOS_NT
+  ptrdiff_t name_len = strlen (name);
+  if (name_len >= 4
+      && c_strcasecmp (name + name_len - 4, ".exe") == 0)
+    sprintf (*dump_file, "%s%c%.*s%s", path, DIRECTORY_SEP,
+	     (int)(name_len - 4), name, suffix);
+  else
+#endif
+    sprintf (*dump_file, "%s%c%s%s",
+	     path, DIRECTORY_SEP, name, suffix);
+  return pdumper_load (*dump_file);
+}
+
 static void
 load_pdump (int argc, char **argv)
 {
@@ -817,6 +866,7 @@
      encoding the system natively uses for filesystem access, so
      there's no need for character set conversion.  */
   ptrdiff_t bufsize;
+  char *argv0_realbase = NULL;
   dump_file = load_pdump_find_executable (argv[0], &bufsize);
 
   /* If we couldn't find our executable, go straight to looking for
@@ -838,6 +888,9 @@
 #ifndef WINDOWSNT
       bufsize = exenamelen + 1;
 #endif
+      /* Save the realpath basename for possible use below */
+      argv0_realbase = xstrdup (load_pdump_basename (real_exename));
+
       if (strip_suffix)
         {
 	  ptrdiff_t strip_suffix_length = strlen (strip_suffix);
@@ -869,55 +922,23 @@
   /* Look for "emacs.pdmp" in PATH_EXEC.  We hardcode "emacs" in
      "emacs.pdmp" so that the Emacs binary still works if the user
      copies and renames it.  */
-  const char *argv0_base = "emacs";
-  ptrdiff_t needed = (strlen (path_exec)
-                      + 1
-                      + strlen (argv0_base)
-                      + strlen (suffix)
-                      + 1);
-  if (bufsize < needed)
+  result = load_pdump_from_path (path_exec, "emacs", suffix,
+				 &dump_file, &bufsize);
+
+  /* Finally, look for basename(argv0)+".pdmp" in PATH_EXEC, using both
+     absolute (realpath) and given forms. This way, they can access emacs
+     via a symlink of a different name, or rename both the executable and
+     its pdump file in PATH_EXEC, and have several Emacs configurations
+     in the same versioned libexec subdirectory.  */
+  if ((result == PDUMPER_LOAD_FILE_NOT_FOUND) && (argv0_realbase != NULL))
     {
-      xfree (dump_file);
-      dump_file = xpalloc (NULL, &bufsize, needed - bufsize, -1, 1);
+      result = load_pdump_from_path (path_exec, argv0_realbase, suffix,
+				     &dump_file, &bufsize);
     }
-  sprintf (dump_file, "%s%c%s%s",
-           path_exec, DIRECTORY_SEP, argv0_base, suffix);
-  result = pdumper_load (dump_file);
-
   if (result == PDUMPER_LOAD_FILE_NOT_FOUND)
     {
-      /* Finally, look for basename(argv0)+".pdmp" in PATH_EXEC.
-	 This way, they can rename both the executable and its pdump
-	 file in PATH_EXEC, and have several Emacs configurations in
-	 the same versioned libexec subdirectory.  */
-      char *p, *last_sep = NULL;
-      for (p = argv[0]; *p; p++)
-	{
-	  if (IS_DIRECTORY_SEP (*p))
-	    last_sep = p;
-	}
-      argv0_base = last_sep ? last_sep + 1 : argv[0];
-      ptrdiff_t needed = (strlen (path_exec)
-			  + 1
-			  + strlen (argv0_base)
-			  + strlen (suffix)
-			  + 1);
-      if (bufsize < needed)
-	{
-	  xfree (dump_file);
-	  dump_file = xmalloc (needed);
-	}
-#ifdef DOS_NT
-      ptrdiff_t argv0_len = strlen (argv0_base);
-      if (argv0_len >= 4
-	  && c_strcasecmp (argv0_base + argv0_len - 4, ".exe") == 0)
-	sprintf (dump_file, "%s%c%.*s%s", path_exec, DIRECTORY_SEP,
-		 (int)(argv0_len - 4), argv0_base, suffix);
-      else
-#endif
-      sprintf (dump_file, "%s%c%s%s",
-	       path_exec, DIRECTORY_SEP, argv0_base, suffix);
-      result = pdumper_load (dump_file);
+      result = load_pdump_from_path (path_exec, load_pdump_basename (argv[0]),
+				     suffix, &dump_file, &bufsize);
     }
 
   if (result != PDUMPER_LOAD_SUCCESS)
@@ -929,6 +950,8 @@
 
  out:
   xfree (dump_file);
+  if (argv0_realbase)
+	  xfree (argv0_realbase);
 }
 #endif /* HAVE_PDUMPER */