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From: James Bottomley <James.Bottomley-d9PhHud1JfjCXq6kfMZ53/egYHeGw8Jk@public.gmane.org>
To: containers-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org,
	linux-fsdevel
	<linux-fsdevel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>
Cc: Jan Kara <jack-AlSwsSmVLrQ@public.gmane.org>,
	Al Viro <viro-3bDd1+5oDREiFSDQTTA3OLVCufUGDwFn@public.gmane.org>
Subject: [Patch v3 3/3] binfmt_misc: add F option description to documentation
Date: Thu, 31 Mar 2016 07:57:10 -0700	[thread overview]
Message-ID: <1459436230.2958.24.camel@HansenPartnership.com> (raw)
In-Reply-To: <1459436046.2958.21.camel-d9PhHud1JfjCXq6kfMZ53/egYHeGw8Jk@public.gmane.org>

Signed-off-by: James Bottomley <James.Bottomley-d9PhHud1JfjCXq6kfMZ53/egYHeGw8Jk@public.gmane.org>
---
 Documentation/binfmt_misc.txt | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/Documentation/binfmt_misc.txt b/Documentation/binfmt_misc.txt
index 6b1de70..ec83bbc 100644
--- a/Documentation/binfmt_misc.txt
+++ b/Documentation/binfmt_misc.txt
@@ -66,6 +66,13 @@ Here is what the fields mean:
             This feature should be used with care as the interpreter
             will run with root permissions when a setuid binary owned by root
             is run with binfmt_misc.
+      'F' - fix binary.  The usual behaviour of binfmt_misc is to spawn the
+      	    binary lazily when the misc format file is invoked.  However,
+	    this doesn't work very well in the face of mount namespaces and
+	    changeroots, so the F mode opens the binary as soon as the
+	    emulation is installed and uses the opened image to spawn the
+	    emulator, meaning it is always available once installed,
+	    regardless of how the environment changes.
 
 
 There are some restrictions:
-- 
2.6.2

      parent reply	other threads:[~2016-03-31 14:57 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-03-31 14:54 [Patch v3 0/3] allow the creation of architecture emulation containers where the emulator binary is outside the container James Bottomley
     [not found] ` <1459436046.2958.21.camel-d9PhHud1JfjCXq6kfMZ53/egYHeGw8Jk@public.gmane.org>
2016-03-31 14:55   ` [Patch v3 1/3] fs: add filp_clone_open API James Bottomley
2016-03-31 14:56   ` [Patch v3 2/3] binfmt_misc: add persistent opened binary handler for containers James Bottomley
     [not found]     ` <1459436179.2958.23.camel-d9PhHud1JfjCXq6kfMZ53/egYHeGw8Jk@public.gmane.org>
2016-04-13 21:02       ` Matthew Helsley
     [not found]         ` <CA+RrjuV3VOjLRMm_bnk-9CKF_3NqX6DVNBgAUVpxW0+NE0bLHg-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2016-04-14 22:33           ` johnny frazier
2016-03-31 14:57   ` James Bottomley [this message]

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