From 2d386993e28c8cca6be7f28271268192c3cbd094 Mon Sep 17 00:00:00 2001
From: Paul Eggert <eggert@cs.ucla.edu>
Date: Sat, 2 Aug 2025 12:58:06 -0700
Subject: [PATCH] tail: prefer readlink to lstat+S_ISLNK

When not already calling lstat for some other reason,
prefer readlink to lstat+S_ISLNK,
as readlink does not suffer from EOVERFLOW issues.
* src/rmdir.c (main):
* src/tail.c (recheck, any_symlinks):
* src/test.c (unary_operator):
---
 src/rmdir.c | 4 ++--
 src/tail.c  | 8 ++++----
 src/test.c  | 4 ++--
 3 files changed, 8 insertions(+), 8 deletions(-)

diff --git a/src/rmdir.c b/src/rmdir.c
index 88fcb2521d..fead0bb198 100644
--- a/src/rmdir.c
+++ b/src/rmdir.c
@@ -269,8 +269,8 @@ main (int argc, char **argv)
                       /* Ensure the last component was a symlink.  */
                       char *dir_arg = xstrdup (dir);
                       strip_trailing_slashes (dir);
-                      ret = lstat (dir, &st);
-                      if (ret == 0 && S_ISLNK (st.st_mode))
+                      char linkbuf[1];
+                      if (0 <= readlink (dir, linkbuf, 1))
                         {
                           error (0, 0,
                                  _("failed to remove %s:"
diff --git a/src/tail.c b/src/tail.c
index 2579f4e13b..5543cc24cd 100644
--- a/src/tail.c
+++ b/src/tail.c
@@ -975,8 +975,8 @@ recheck (struct File_spec *f, bool blocking)
      then mark the file as not tailable.  */
   f->tailable = !(reopen_inaccessible_files && fd < 0);
 
-  if (! disable_inotify && ! lstat (f->name, &new_stats)
-      && S_ISLNK (new_stats.st_mode))
+  char linkbuf[1];
+  if (! disable_inotify && 0 <= readlink (f->name, linkbuf, 1))
     {
       /* Diagnose the edge case where a regular file is changed
          to a symlink.  We avoid inotify with symlinks since
@@ -1352,9 +1352,9 @@ any_non_remote_file (const struct File_spec *f, int n_files)
 static bool
 any_symlinks (const struct File_spec *f, int n_files)
 {
-  struct stat st;
+  char linkbuf[1];
   for (int i = 0; i < n_files; i++)
-    if (lstat (f[i].name, &st) == 0 && S_ISLNK (st.st_mode))
+    if (0 <= readlink (f[i].name, linkbuf, 1))
       return true;
   return false;
 }
diff --git a/src/test.c b/src/test.c
index fd9aa0d294..583cf74c9c 100644
--- a/src/test.c
+++ b/src/test.c
@@ -464,8 +464,8 @@ unary_operator (void)
 
     case 'h':			/* File is a symbolic link? */
       unary_advance ();
-      return (lstat (argv[pos - 1], &stat_buf) == 0
-              && S_ISLNK (stat_buf.st_mode));
+      char linkbuf[1];
+      return 0 <= readlink (argv[pos - 1], linkbuf, 1);
 
     case 'u':			/* File is setuid? */
       unary_advance ();
-- 
2.47.2