Date: Sat, 1 Sep 2012 17:33:56 +0200 From: Holger Hans Peter Freyther <holger@freyther.de> To: freebsd-emulation@freebsd.org Subject: Re: Linux SHM inside a jail Message-ID: <20120901153356.GW1299@localhost> In-Reply-To: <20120822164106.GE4301@localhost> References: <20120822164106.GE4301@localhost>
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On Wed, Aug 22, 2012 at 06:41:06PM +0200, Holger Hans Peter Freyther wrote:
> PS: I looked at both GLIBC ntpl/sem_open.c and linux_stats.c. One option
> would be to list another directory in /proc/mounts with tmpfs/shmfs and
> replicate the check in linux_stats.c for this alternative directory.
I went ahead and explored this route and created the following patch. Does
anyone have an idea how to make it work with a custom devfs.rule? With the
below patch I can use/run the python multiprocess module inside a jail.
comments?
>From 3eeb57564e0fb6b7234e3db50309fd359701d9dc Mon Sep 17 00:00:00 2001
From: Holger Hans Peter Freyther <holger@freyther.de>
Date: Sat, 1 Sep 2012 17:20:42 +0200
Subject: [PATCH] Announce shm on /tmp/shm
Make linprocfs announce shm and let statfs return the shmfs magic
for this directory. This makes it easy to use shmfs inside a jail.
---
sys/compat/linprocfs/linprocfs.c | 4 ++++
sys/compat/linux/linux_stats.c | 4 +++-
2 files changed, 7 insertions(+), 1 deletion(-)
diff --git a/sys/compat/linprocfs/linprocfs.c b/sys/compat/linprocfs/linprocfs.c
index 3adbe96..9a2f97e 100644
--- a/sys/compat/linprocfs/linprocfs.c
+++ b/sys/compat/linprocfs/linprocfs.c
@@ -390,6 +390,10 @@ linprocfs_domtab(PFS_FILL_ARGS)
/* a real Linux mtab will also show NFS options */
sbuf_printf(sb, " 0 0\n");
}
+
+ /* Add a mountpoint for shm inside jails */
+ sbuf_printf(sb, "tmpfs /tmp/shm tmpfs rw,nosuid,nodev,relatime 0 0\n");
+
mtx_unlock(&mountlist_mtx);
if (flep != NULL)
free(flep, M_TEMP);
diff --git a/sys/compat/linux/linux_stats.c b/sys/compat/linux/linux_stats.c
index 2e05c85..7411570 100644
--- a/sys/compat/linux/linux_stats.c
+++ b/sys/compat/linux/linux_stats.c
@@ -409,9 +409,11 @@ linux_statfs(struct thread *td, struct linux_statfs_args *args)
#endif
dev_shm = 0;
error = kern_statfs(td, path, UIO_SYSSPACE, &bsd_statfs);
- if (strncmp(path, "/dev/shm", sizeof("/dev/shm") - 1) == 0)
+ if (strncmp(path, "/dev/shm", sizeof("/dev/shm") - 1) == 0 ||
+ strncmp(path, "/tmp/shm", sizeof("/tmp/shm") - 1) == 0)
dev_shm = (path[8] == '\0'
|| (path[8] == '/' && path[9] == '\0'));
+
LFREEPATH(path);
if (error)
return (error);
--
1.7.11.5
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