From: Paul Eggert <eggert@cs.ucla.edu>
Date: Thu, 24 Jul 2025 12:17:35 +0000 (-0700)
Subject: Prefer readlink to lstat in find_emacs_executable
X-Git-Url: http://git.eshelyaron.com/gitweb/?a=commitdiff_plain;h=db179c7aacb63a11271a5a0932734011a7edb5bb;p=emacs.git

Prefer readlink to lstat in find_emacs_executable

* src/emacs.c (find_emacs_executable): Prefer readlink to lstat
when testing whether a file is a symlink.  This avoids EOVERFLOW
issues.

(cherry picked from commit 67ea9485a65dee4fb654f1bc177c71028d020607)
---

diff --git a/src/emacs.c b/src/emacs.c
index 1239bb7bfda..0e10398dc78 100644
--- a/src/emacs.c
+++ b/src/emacs.c
@@ -760,6 +760,7 @@ find_emacs_executable (char const *argv0, ptrdiff_t *candidate_size)
   return prog_fname ? xstrdup (prog_fname) : NULL;
 #else  /* !WINDOWSNT */
   char *candidate = NULL;
+  char linkbuf[1];
 
   /* If the executable name contains a slash, we have some kind of
      path already, so just resolve symlinks and return the result.  */
@@ -820,7 +821,7 @@ find_emacs_executable (char const *argv0, ptrdiff_t *candidate_size)
 	  /* People put on PATH a symlink to the real Emacs
 	     executable, with all the auxiliary files where the real
 	     executable lives.  Support that.  */
-	  if (lstat (candidate, &st) == 0 && S_ISLNK (st.st_mode))
+	  if (0 <= readlink (candidate, linkbuf, sizeof linkbuf))
 	    {
 	      char *real_name = realpath (candidate, NULL);