From 25368b5249509aa21167b7ea4193e281f0091f55 Mon Sep 17 00:00:00 2001 From: Ferenc Wagner Date: Mon, 10 May 2010 11:50:10 +0200 Subject: [PATCH] no need to use a temporary directory for pivoting Ferenc Wagner writes: > Daniel Lezcano writes: > >> Ferenc Wagner wrote: >> >>> Daniel Lezcano writes: >>> >>>> Ferenc Wagner wrote: >>>> >>>>> While playing with lxc-start, I noticed that /tmp is infested by >>>>> empty lxc-r* directories: [...] Ok, this name comes from lxc-rootfs >>>>> in conf.c:setup_rootfs. After setup_rootfs_pivot_root returns, the >>>>> original /tmp is not available anymore, so rmdir(tmpname) at the >>>>> bottom of setup_rootfs can't achieve much. Why is this temporary >>>>> name needed anyway? Is pivoting impossible without it? >>>> >>>> That was put in place with chroot, before pivot_root, so the distro's >>>> scripts can remount their '/' without failing. >>>> >>>> Now we have pivot_root, I suppose we can change that to something cleaner... >>> >>> Like simply nuking it? Shall I send a patch? >> >> Sure, if we can kill it, I will be glad to take your patch :) > > I can't see any reason why lxc-start couldn't do without that temporary > recursive bind mount of the original root. If neither do you, I'll > patch it out and see if it still flies. For my purposes the patch below works fine. I only run applications, though, not full systems, so wider testing is definitely needed. Thanks, Feri. >From 98b24c13f809f18ab8969fb4d84defe6f812b25c Mon Sep 17 00:00:00 2001 Date: Thu, 6 May 2010 14:47:39 +0200 That was put in place before lxc-start started using pivot_root, so the distro scripts can remount / without problems. Signed-off-by: Ferenc Wagner Signed-off-by: Daniel Lezcano --- src/lxc/conf.c | 27 +++++++-------------------- 1 file changed, 7 insertions(+), 20 deletions(-) diff --git a/src/lxc/conf.c b/src/lxc/conf.c index 213be5537..257541371 100644 --- a/src/lxc/conf.c +++ b/src/lxc/conf.c @@ -581,37 +581,24 @@ static int setup_rootfs_pivot_root(const char *rootfs, const char *pivotdir) static int setup_rootfs(const char *rootfs, const char *pivotdir) { - char *tmpname; - int ret = -1; + const char *tmpfs = "/tmp"; if (!rootfs) return 0; - tmpname = tempnam("/tmp", "lxc-rootfs"); - if (!tmpname) { - SYSERROR("failed to generate temporary name"); + if (mount(rootfs, tmpfs, "none", MS_BIND|MS_REC, NULL)) { + SYSERROR("failed to mount '%s'->'%s'", rootfs, "/tmp"); return -1; } - if (mkdir(tmpname, 0700)) { - SYSERROR("failed to create temporary directory '%s'", tmpname); - return -1; - } + DEBUG("mounted '%s' on '%s'", rootfs, tmpfs); - if (mount(rootfs, tmpname, "none", MS_BIND|MS_REC, NULL)) { - SYSERROR("failed to mount '%s'->'%s'", rootfs, tmpname); - goto out; - } - - if (setup_rootfs_pivot_root(tmpname, pivotdir)) { + if (setup_rootfs_pivot_root(tmpfs, pivotdir)) { ERROR("failed to pivot_root to '%s'", rootfs); - goto out; + return -1; } - ret = 0; -out: - rmdir(tmpname); - return ret; + return 0; } static int setup_pts(int pts)