From e30af1e5840fdcabe3856f9ffcd6354b94d0a7ee Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?P=C3=A1draig=20Brady?= <P@draigBrady.com>
Date: Mon, 6 Mar 2023 13:01:26 +0000
Subject: tail,tee: avoid issues with many files on systems without poll

* src/iopoll.c (iopoll): Protect the call to select against
passing in a descriptor larger than FD_SETSIZE.
---
 src/iopoll.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/src/iopoll.c b/src/iopoll.c
index a73ce05bf..ca27595e3 100644
--- a/src/iopoll.c
+++ b/src/iopoll.c
@@ -86,6 +86,12 @@ iopoll (int fdin, int fdout, bool block)
   int nfds = (fdin > fdout ? fdin : fdout) + 1;
   int ret = 0;
 
+  if (FD_SETSIZE < nfds)
+    {
+      errno = EINVAL;
+      ret = -1;
+    }
+
   /* If fdout has an error condition (like a broken pipe) it will be seen
      as ready for reading.  Assumes fdout is not actually readable.  */
   while (0 <= ret || errno == EINTR)
-- 
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