From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 9E5F244998D for ; Thu, 9 Jul 2026 18:53:16 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.129.124 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1783623198; cv=none; b=UWJ9e+cGNBPKs5YrEjxu4qwoM8srWb8iYnrKZGXPTKADZSrWnEGFvqjNUbgVw6sdW4sf/gTeFaZEhkzBJUi8YSCRr7+ZoHm+aKxB/MaU/uXayCgZ7vlfUYj2ycG3gZe3bxx1fnY8ahMSOlcEW/uoDgnMf7ZVOwiAIBG4RbMd5ZE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1783623198; c=relaxed/simple; bh=7/vd18ml8GWw+tDhE/H/B3TCaD9VtiMZiHeKO5+nQ4Y=; h=Date:Message-Id:From:To:Cc:Subject; b=Nk8IOpKOylHYb0Bl94RruPyvNF0GId6zXaAvIwRsxnmMBg5e5lsFleSHIoUejUDNSN6Cc5x7/ASmv3rNogHcrZClF6bBDpC0bO3rwrFdwdnbY67rvMCOUY+G8i5+lRkgbsHfLqvpDqZ8/ZPv+B0zWcM8rs98W0WdeBQUWCVG8O4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com; spf=pass smtp.mailfrom=redhat.com; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b=THHCGS/7; arc=none smtp.client-ip=170.10.129.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=redhat.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="THHCGS/7" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1783623195; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc; bh=yarLs+0jJ30X1GlZLAgBHE+DP9InEkx/pXADczPiCD8=; b=THHCGS/7e63/Hig8bH2ZcVFnRNu6XKbOv8zkRoV0aI6qEji6cO8XWgAgg2R2FbXaopvul/ hJihVmviOSyx5sL4uAtYgt91rsPVM7faviWj6ozMEKk25BGgIOuS6w+9e7y/ojZt2r/N4j xThRKXA2LnQYYxz7nCkmfg9BJfOFM/0= Received: from mx-prod-mc-03.mail-002.prod.us-west-2.aws.redhat.com (ec2-54-186-198-63.us-west-2.compute.amazonaws.com [54.186.198.63]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-539-O4KcX4KRP5mdTEiepYjIKg-1; Thu, 09 Jul 2026 14:53:12 -0400 X-MC-Unique: O4KcX4KRP5mdTEiepYjIKg-1 X-Mimecast-MFC-AGG-ID: O4KcX4KRP5mdTEiepYjIKg_1783623191 Received: from mx-prod-int-03.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-03.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.12]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mx-prod-mc-03.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 607E319560B2; Thu, 9 Jul 2026 18:53:11 +0000 (UTC) Received: from greed.delorie.com (unknown [10.22.89.250]) by mx-prod-int-03.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 14C63195608A; Thu, 9 Jul 2026 18:53:10 +0000 (UTC) Received: from greed.delorie.com.redhat.com (localhost [127.0.0.1]) by greed.delorie.com (8.16.1/8.16.1) with ESMTP id 669Ir9j9459288; Thu, 9 Jul 2026 14:53:09 -0400 Date: Thu, 09 Jul 2026 14:53:09 -0400 Message-Id: From: DJ Delorie To: Alejandro Colomar Cc: Subject: man/man8/ldconfig.8: document system-wide tunables X-Scanned-By: MIMEDefang 3.0 on 10.30.177.12 Precedence: bulk X-Mailing-List: linux-man@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: diff --git a/man/man8/ldconfig.8 b/man/man8/ldconfig.8 index ee024b8f6..8574eae24 100644 --- a/man/man8/ldconfig.8 +++ b/man/man8/ldconfig.8 @@ -17,6 +17,8 @@ .SH SYNOPSIS .IR conf ] .RB [ \-r\~\c .IR root ] +.RB [ \-t\~\c +.IR tunconf ] .IR directory \~.\|.\|. .YS .SY /sbin/ldconfig @@ -85,6 +87,11 @@ .SH DESCRIPTION .P Failure to follow this pattern may result in compatibility issues after an upgrade. +.P +If the file +.IR /etc/tunables.conf +exists, it contains one tunable per line. These tunables are stored +in the cache and applied to every process at its startup. .SH OPTIONS .TP .BI \-\-format= fmt @@ -157,6 +164,12 @@ .SH OPTIONS .I root as the root directory. .TP +.BI \-t\~ tunconf +Use +.I tunconf +instead of +.IR /etc/tunables.conf . +.TP .B \-\-verbose .TQ .B \-v @@ -177,9 +190,85 @@ .SH OPTIONS .B \-N is also specified, the cache is still rebuilt. +.SH INCLUDES +The files +.IR /etc/ld.so.conf +and +.IR /etc/tunables.conf +allow lines to start with the word +.I include +followed by a path wildcard, and will include any files matching that +wildcard. +.SH TUNABLES +Each line in the file +.I /etc/tunables.conf +specifies a tunable, which is a name and value +separated by an equals sign. +Each line may include zero or more words or symbols at the beginning: +.TP +.B overridable +.TQ +.B + +Allow the tunable to be overridden by the environment variable (this is the default). +.TP +.B nonoverridable +.TQ +.B \- +Do not allow the tunable to be overridden by the environment variable. +.TP +.B onlysecure +.TQ +.B @ +The tunable only applies to AT_SECURE (i.e. setuid, or elevated +capabilities) processes. +.TP +.B nonsecure +.TQ +.B $ +The tunable only applies to non-AT_SECURE processes (this is the default). +.TP +.B anysecure +.TQ +.B * +The tunable only applies to both AT_SECURE and non-AT_SECURE processes. +.P +The file may also contain +.I filters , +which limit the tunables following it, up to the end of the file (or +end of the included file, or start of a new included file) or a line +with only +.B [] +on it. The syntax is: +.RS +.P +[ +.I filter +: +.I pattern +] +.RE +.P +.TP +.B proc +The +.I proc +filter limits the following tunables to processes starting from the +file matching the pattern. The file may be fully qualified or just +the basename. +.P +Example config file: +.P +.RS +.nf +glibc.malloc.arenas_max=5 +onlysecure glibc.malloc.arenas_max=1 +-glibc.pthread.rseq=1 +[proc:/bin/bad.program] +-glibc.pthread.rseq=0 +.fi +.RE +.P .SH FILES -.\" FIXME Since glibc-2.3.4, "include" directives are supported in ld.so.conf -.\" .\" FIXME Since glibc-2.4, "hwcap" directives are supported in ld.so.conf .PD 0 .TP @@ -191,6 +280,11 @@ .SH FILES one per line, in which to search for libraries. .TP +.I /etc/tunables.conf +contains a list of tunables, +one per line, +to apply to all newly created processes. +.TP .I /etc/ld.so.cache contains an ordered list of libraries found in the directories specified in