From 0979b3a68b820cd60a0c2618c2ac89f288eb341d Mon Sep 17 00:00:00 2001
From: Amos Jeffries <squid3@treenet.co.nz>
Date: Sat, 12 Jun 2010 22:53:08 +1200
Subject: [PATCH] Restrict limited select() I/O loop below FD_SETSIZE.

Henrik informs that loosp using fd_set() (select and win32-select) must
be kept below FD_SETSIZE or they can hang Squid or cause out-of-bounds
memory errors.

NP: Squid-2 does not appear to limit select() like this. May need fixing too.
---
 src/tools.cc | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/src/tools.cc b/src/tools.cc
index c88ee054f7..998d51dbb3 100644
--- a/src/tools.cc
+++ b/src/tools.cc
@@ -888,7 +888,13 @@ setMaxFD(void)
     if (getrlimit(RLIMIT_NOFILE, &rl) < 0) {
         debugs(50, DBG_CRITICAL, "setrlimit: RLIMIT_NOFILE: " << xstrerror());
     } else if (Config.max_filedescriptors > 0) {
-        rl.rlim_cur = Config.max_filedescriptors;
+#if USE_SELECT || USE_SELECT_WIN32
+        /* select() breaks if this gets set too big */
+        if (Config.max_filedescriptors > FD_SETSIZE)
+            rl.rlim_cur = FD_SETSIZE;
+        else
+#endif
+            rl.rlim_cur = Config.max_filedescriptors;
         if (rl.rlim_cur > rl.rlim_max)
             rl.rlim_max = rl.rlim_cur;
         if (setrlimit(RLIMIT_NOFILE, &rl)) {
-- 
2.47.3