[CRIU] [PATCH v3 05/33] ns: Set nested namespaces hookups
Andrei Vagin
avagin at virtuozzo.com
Tue Feb 21 20:43:48 PST 2017
On Tue, Feb 21, 2017 at 02:53:38PM +0300, Kirill Tkhai wrote:
> On 21.02.2017 08:45, Andrei Vagin wrote:
> > On Thu, Feb 16, 2017 at 03:07:19PM +0300, Kirill Tkhai wrote:
> >> Introduce ns_id::parent and assign a pointer to parent
> >> for every ns except NS_CRIU and NS_ROOT.
> >> Also populate user_ns for pid_ns.
> >>
> >> Signed-off-by: Kirill Tkhai <ktkhai at virtuozzo.com>
> >> ---
> >> criu/include/namespaces.h | 12 ++++++
> >> criu/namespaces.c | 87 +++++++++++++++++++++++++++++++++++++++++++++
> >> 2 files changed, 99 insertions(+)
> >>
> >> diff --git a/criu/include/namespaces.h b/criu/include/namespaces.h
> >> index 1b454e0c1..69df0313b 100644
> >> --- a/criu/include/namespaces.h
> >> +++ b/criu/include/namespaces.h
> >> @@ -1,6 +1,8 @@
> >> #ifndef __CR_NS_H__
> >> #define __CR_NS_H__
> >>
> >> +#include <sys/ioctl.h>
> >> +
> >> #include "common/compiler.h"
> >> #include "files.h"
> >> #include "common/list.h"
> >> @@ -40,6 +42,12 @@
> >>
> >> #define EXTRA_SIZE 20
> >>
> >> +#ifndef NSIO
> >> +#define NSIO 0xb7
> >> +#define NS_GET_USERNS _IO(NSIO, 0x1)
> >> +#define NS_GET_PARENT _IO(NSIO, 0x2)
> >> +#endif
> >> +
> >> struct ns_desc {
> >> unsigned int cflag;
> >> char *str;
> >> @@ -76,6 +84,10 @@ struct ns_id {
> >> unsigned int id;
> >> pid_t ns_pid;
> >> struct ns_desc *nd;
> >> + struct ns_id *parent;
> >> + struct list_head children;
> >> + struct list_head siblings;
> >> + struct ns_id *user_ns;
> >> struct ns_id *next;
> >> enum ns_type type;
> >>
> >> diff --git a/criu/namespaces.c b/criu/namespaces.c
> >> index 9e61c9481..c4ef52733 100644
> >> --- a/criu/namespaces.c
> >> +++ b/criu/namespaces.c
> >> @@ -13,6 +13,7 @@
> >> #include <sys/stat.h>
> >> #include <limits.h>
> >> #include <errno.h>
> >> +#include <sys/ioctl.h>
> >>
> >> #include "page.h"
> >> #include "rst-malloc.h"
> >> @@ -302,6 +303,8 @@ struct ns_id *rst_new_ns_id(unsigned int id, pid_t pid,
> >> nsid->type = type;
> >> nsid_add(nsid, nd, id, pid);
> >> nsid->ns_populated = false;
> >> + INIT_LIST_HEAD(&nsid->children);
> >> + INIT_LIST_HEAD(&nsid->siblings);
> >> }
> >>
> >> return nsid;
> >> @@ -421,6 +424,8 @@ static unsigned int generate_ns_id(int pid, unsigned int kid, struct ns_desc *nd
> >> nsid->type = type;
> >> nsid->kid = kid;
> >> nsid->ns_populated = true;
> >> + INIT_LIST_HEAD(&nsid->children);
> >> + INIT_LIST_HEAD(&nsid->siblings);
> >> nsid_add(nsid, nd, ns_next_id++, pid);
> >>
> >> found:
> >> @@ -661,6 +666,88 @@ int dump_task_ns_ids(struct pstree_item *item)
> >> return 0;
> >> }
> >>
> >> +static int set_ns_opt(int ns_fd, unsigned ioc, struct ns_id **ns, struct ns_desc *nd)
> >> +{
> >> + int opt_fd, ret = -1;
> >> + struct stat st;
> >> +
> >> + opt_fd = ioctl(ns_fd, ioc);
> >> + if (opt_fd < 0) {
> >> + pr_info("Can't do ns ioctl %x\n", ioc);
> >> + return -errno;
> >> + }
> >> + if (fstat(opt_fd, &st) < 0) {
> >> + pr_perror("Unable to stat on ns fd");
> >> + ret = -errno;
> >> + goto out;
> >> + }
> >> + *ns = lookup_ns_by_kid(st.st_ino, nd);
> >> + if (!*ns) {
> >> + pr_err("Namespaces hierarhies with holes are not supported\n");
> >> + ret = -EINVAL;
> >> + goto out;
> >> + }
> >> + ret = 0;
> >> +out:
> >> + close(opt_fd);
> >> + return ret;
> >> +}
> >> +
> >> +static int set_ns_hookups(struct ns_id *ns)
> >> +{
> >> + struct ns_desc *nd = ns->nd;
> >> + struct ns_id *u_ns;
> >> + int fd, ret = -1;
> >> +
> >> + fd = open_proc(ns->ns_pid, "ns/%s", nd->str);
> >> + if (fd < 0) {
> >> + pr_perror("Can't open %s, pid %d", nd->str, ns->ns_pid);
> >> + return -1;
> >> + }
> >> +
> >> + if (ns->type != NS_ROOT && (nd == &pid_ns_desc || nd == &user_ns_desc)) {
> >> + if (set_ns_opt(fd, NS_GET_PARENT, &ns->parent, nd) < 0)
> >> + goto out;
> >> + if (ns->parent && ns->parent->type == NS_CRIU) {
> >> + pr_err("Wrong determined NS_ROOT, or root_item has NS_OTHER user_ns\n");
> >> + goto out;
> >> + }
> >> + list_add(&ns->siblings, &ns->parent->children);
> >> + }
> >> +
> >> + if (nd != &user_ns_desc) {
> >> + ret = set_ns_opt(fd, NS_GET_USERNS, &ns->user_ns, &user_ns_desc);
> >> + if (ret == -ENOTTY) {
> >> + pr_info("Can't get user_ns of %s %u, assuming NS_ROOT\n",
> >> + nd->str, ns->id);
> >
> > It is possible only if we dump only one userns.
>
> Sure, and if we have several user_ns, we'll fail on NS_GET_PARENT made for one of them.
pls, add a comment here about this.
>
> >> + u_ns = NULL;
> >> + if (root_ns_mask & CLONE_NEWUSER) {
> >> + for (u_ns = ns_ids; u_ns; u_ns = u_ns->next) {
> >> + if (u_ns->nd == &user_ns_desc && u_ns->type == NS_ROOT)
> >> + break;
> >> + }
> >> + if (!u_ns) {
> >> + pr_err("Can't find root user_ns\n");
> >> + goto out;
> >> + }
> >> + }
> >> + ns->user_ns = u_ns;
> >> + } else if (ret < 0) {
> >> + goto out;
> >> + } else if (ns->user_ns->type == NS_CRIU) {
> >> + if (root_ns_mask & CLONE_NEWUSER) {
> >> + pr_err("Must not be criu user_ns\n");
> >
> > ret is zero here
>
> Yeah, I'll fix that.
>
> >
> >> + goto out;
> >> + }
> >> + ns->user_ns = NULL;
> >> + }
> >> + }
> >> + ret = 0;
> >> +out:
> >> + close(fd);
> >> + return ret;
> >> +}
> >> +
> >> static UsernsEntry userns_entry = USERNS_ENTRY__INIT;
> >> #define INVALID_ID (~0U)
> >>
> >>
> >> _______________________________________________
> >> CRIU mailing list
> >> CRIU at openvz.org
> >> https://lists.openvz.org/mailman/listinfo/criu
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