[Devel] [PATCH v4 7/7] allow for distro-specific fix ups at creation time.
Glauber Costa
glommer at openvz.org
Tue May 14 03:52:52 PDT 2013
From: Glauber Costa <glommer at parallels.com>
We will need that infrastucture when running with Linux upstream, since some
support is very unlikely to ever land in the Kernel. We need to do things like
account for the fact that udev may kick in and destroy all the setup we have
done for /dev. Since preemptively preventing those actions to happen is very
hard ( as an example, centos6 init binary will issue mount syscalls itself),
the most robust approach is to insert a script that will be run shortly after
rc.sysinit. Although this can't guarantee that it will run *immediately* after,
it should be early enough to undo every harmful operation done by /sbin/init
and rc.sysinit, therefore allowing operation to continue freely.
Signed-off-by: Glauber Costa <glommer at parallels.com>
---
etc/dists/redhat.conf | 1 +
etc/dists/scripts/fixups.sh | 43 +++++++++++++++++++++++++++++++++++++++++++
include/dist.h | 2 ++
include/env.h | 3 ++-
src/lib/dist.c | 10 +++++++++-
src/lib/env.c | 10 ++++++----
src/lib/exec.c | 2 +-
src/lib/hooks_ct.c | 38 ++++++++++++++++++++++++++++++++++++++
8 files changed, 102 insertions(+), 7 deletions(-)
create mode 100755 etc/dists/scripts/fixups.sh
diff --git a/etc/dists/redhat.conf b/etc/dists/redhat.conf
index 727461d..49226c5 100644
--- a/etc/dists/redhat.conf
+++ b/etc/dists/redhat.conf
@@ -25,3 +25,4 @@ SET_DNS=set_dns.sh
SET_USERPASS=set_userpass.sh
SET_UGID_QUOTA=set_ugid_quota.sh
POST_CREATE=postcreate.sh
+CT_FIXUP=fixups.sh
diff --git a/etc/dists/scripts/fixups.sh b/etc/dists/scripts/fixups.sh
new file mode 100755
index 0000000..da3fd24
--- /dev/null
+++ b/etc/dists/scripts/fixups.sh
@@ -0,0 +1,43 @@
+#!/bin/bash
+# Copyright (C) 2000-2009, Parallels, Inc. All rights reserved.
+#
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 2 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program; if not, write to the Free Software
+# Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+#
+#
+# Run-time fixup for legacy distributions that will rely on udevd to populate
+# their /dev. Those distributions will effectively mount an empty tmpfs on top
+# of /dev, defeating any setup we may have done. This includes RHEL-based
+# distributions up to RHEL6. We are better off not allowing that to run at all
+
+function fixup_udev()
+{
+ if [ -f /etc/fedora-release ]; then
+ return;
+ fi
+
+ # All the first two may fail if the distribution didn't actually mount
+ # then.
+ umount /dev/pts
+ umount /dev/shm
+ # still may hold references to files open by rc.sysinit. Even if this is the
+ # case those will be simple things like /dev/null and should go away shortly.
+ # let us not fail because of that.
+ umount /dev -l
+}
+
+fixup_udev
+
+exit 0
+
diff --git a/include/dist.h b/include/dist.h
index 1f6a5a6..4faa452 100644
--- a/include/dist.h
+++ b/include/dist.h
@@ -29,6 +29,7 @@
#define SET_USERPASS 5
#define SET_UGID_QUOTA 6
#define POST_CREATE 7
+#define CT_FIXUP 8
typedef struct {
char *def_ostmpl;
@@ -46,6 +47,7 @@ typedef struct dist_actions {
char *set_userpass; /**< setup user password. */
char *set_ugid_quota; /**< setup 2level quota. */
char *post_create; /**< sostcreate actions. */
+ char *ct_fixup; /**< run-time fixups. */
} dist_actions;
/* Read distribution specific actions configuration file.
diff --git a/include/env.h b/include/env.h
index 35d427f..223c3a3 100644
--- a/include/env.h
+++ b/include/env.h
@@ -106,7 +106,7 @@ int vps_stop(vps_handler *h, envid_t veid, vps_param *param, int stop_mode,
int vz_chroot(const char *root);
int vz_env_create(vps_handler *h, envid_t veid, vps_res *res,
int wait_p[2], int old_wait_p[2], int err_p[2],
- env_create_FN fn, void *data);
+ env_create_FN fn, dist_actions *actions, void *data);
struct vps_res;
struct arg_start {
@@ -118,6 +118,7 @@ struct arg_start {
vps_handler *h;
void *data;
env_create_FN fn;
+ dist_actions *actions;
int userns_p; /* while running in userns, there's extra sync needed */
};
diff --git a/src/lib/dist.c b/src/lib/dist.c
index bde94ab..8047cf7 100644
--- a/src/lib/dist.c
+++ b/src/lib/dist.c
@@ -36,7 +36,8 @@ static struct distr_conf {
{"SET_DNS", SET_DNS},
{"SET_USERPASS", SET_USERPASS},
{"SET_UGID_QUOTA", SET_UGID_QUOTA},
- {"POST_CREATE", POST_CREATE}
+ {"POST_CREATE", POST_CREATE},
+ {"CT_FIXUP", CT_FIXUP }
};
static int get_action_id(char *name)
@@ -100,6 +101,12 @@ static int add_dist_action(dist_actions *d_actions, char *name, char *action,
break;
d_actions->post_create = strdup(file);
break;
+ case CT_FIXUP:
+ if (d_actions->ct_fixup != NULL)
+ break;
+ d_actions->ct_fixup = strdup(file);
+ break;
+
}
return 0;
}
@@ -115,6 +122,7 @@ void free_dist_actions(dist_actions *d_actions)
free(d_actions->set_userpass);
free(d_actions->set_ugid_quota);
free(d_actions->post_create);
+ free(d_actions->ct_fixup);
}
static int get_dist_conf_name(char *dist_name, char *dir, char *file, int len)
diff --git a/src/lib/env.c b/src/lib/env.c
index 166c83b..0d47b89 100644
--- a/src/lib/env.c
+++ b/src/lib/env.c
@@ -301,7 +301,8 @@ int exec_container_init(struct arg_start *arg,
}
static int vz_real_env_create(vps_handler *h, envid_t veid, vps_res *res,
- int wait_p, int old_wait_p, int err_p, env_create_FN fn, void *data)
+ int wait_p, int old_wait_p, int err_p, env_create_FN fn, dist_actions *actions,
+ void *data)
{
struct arg_start arg;
@@ -314,6 +315,7 @@ static int vz_real_env_create(vps_handler *h, envid_t veid, vps_res *res,
arg.h = h;
arg.data = data;
arg.fn = fn;
+ arg.actions = actions;
return h->env_create(&arg);
}
@@ -420,7 +422,7 @@ static void get_osrelease(vps_res *res)
int vz_env_create(vps_handler *h, envid_t veid, vps_res *res,
int wait_p[2], int old_wait_p[2], int err_p[2],
- env_create_FN fn, void *data)
+ env_create_FN fn, dist_actions *actions, void *data)
{
int ret, pid, errcode;
int old_wait_fd;
@@ -462,7 +464,7 @@ int vz_env_create(vps_handler *h, envid_t veid, vps_res *res,
old_wait_fd = -1;
ret = vz_real_env_create(h, veid, res, wait_p[0],
- old_wait_fd, err_p[1], fn, data);
+ old_wait_fd, err_p[1], fn, actions, data);
if (ret)
write(STDIN_FILENO, &ret, sizeof(ret));
exit(ret);
@@ -636,7 +638,7 @@ int vps_start_custom(vps_handler *h, envid_t veid, vps_param *param,
fix_cpu(&res->cpu);
ret = vz_env_create(h, veid, res, wait_p,
- old_wait_p, err_p, fn, data);
+ old_wait_p, err_p, fn, &actions, data);
if (ret)
goto err;
diff --git a/src/lib/exec.c b/src/lib/exec.c
index 9cf811c..74375dd 100644
--- a/src/lib/exec.c
+++ b/src/lib/exec.c
@@ -454,7 +454,7 @@ int vps_run_script(vps_handler *h, envid_t veid, char *script, vps_param *vps_p)
}
}
if ((ret = vz_env_create(h, veid, &vps_p->res, rd_p, NULL,
- wr_p, NULL, NULL)))
+ wr_p, NULL, NULL, NULL)))
{
return ret;
}
diff --git a/src/lib/hooks_ct.c b/src/lib/hooks_ct.c
index 8695985..8dc7715 100644
--- a/src/lib/hooks_ct.c
+++ b/src/lib/hooks_ct.c
@@ -365,6 +365,43 @@ static int _env_create(void *data)
return exec_container_init(arg, &create_param);
}
+static int apply_fixups(vps_handler *h, envid_t veid, const char *root, dist_actions *actions)
+{
+ char buf[STR_SIZE];
+
+ /* Distributions that don't need the fixup will can stop right here */
+ if (!actions || !actions->ct_fixup)
+ return 0;
+
+ if (snprintf(buf, sizeof(buf), "%s/%s", root, "/etc/rc3.d/S00vz-fixups.sh") < 0)
+ goto out;
+
+ if (open(buf, O_RDWR|O_CREAT, 0) < 0)
+ goto out;
+
+ if (mount(actions->ct_fixup, buf, "", MS_BIND, 0) < 0)
+ goto out;
+
+ /*
+ * Being safe never killed anyone...
+ * We bind mount instead of symlinking the original rc3 so it won't appear in the original
+ * private mount.
+ */
+ if (snprintf(buf, sizeof(buf), "%s/%s", root, "/etc/rc5.d/S00vz-fixups.sh") < 0)
+ goto out;
+
+ if (open(buf, O_RDWR|O_CREAT, 0) < 0)
+ goto out;
+
+ if (mount(actions->ct_fixup, buf, "", MS_BIND, 0) < 0)
+ goto out;
+ return 0;
+
+out:
+ logger(-1, errno, "Could not install fixup script\n");
+ return VZ_RESOURCE_ERROR;
+}
+
static int ct_env_create(struct arg_start *arg)
{
@@ -433,6 +470,7 @@ static int ct_env_create(struct arg_start *arg)
if (arg->h->can_join_userns) {
create_devices(arg->h, arg->veid, arg->res->fs.root);
+ apply_fixups(arg->h, arg->veid, arg->res->fs.root, arg->actions);
}
ret = clone(_env_create, child_stack, clone_flags, arg);
--
1.7.11.7
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