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namespaces.c
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namespaces.c
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#include <unistd.h>
#include <fcntl.h>
#include <sys/wait.h>
#include <stdlib.h>
#include <sys/prctl.h>
#include <grp.h>
#include <sys/socket.h>
#include <sys/un.h>
#include <stdarg.h>
#include <signal.h>
#include "cr-show.h"
#include "util.h"
#include "imgset.h"
#include "syscall.h"
#include "uts_ns.h"
#include "ipc_ns.h"
#include "mount.h"
#include "pstree.h"
#include "namespaces.h"
#include "net.h"
#include "protobuf.h"
#include "protobuf/ns.pb-c.h"
#include "protobuf/userns.pb-c.h"
static struct ns_desc *ns_desc_array[] = {
&net_ns_desc,
&uts_ns_desc,
&ipc_ns_desc,
&pid_ns_desc,
&user_ns_desc,
&mnt_ns_desc,
};
static unsigned int parse_ns_link(char *link, size_t len, struct ns_desc *d)
{
unsigned long kid = 0;
char *end;
if (len >= d->len + 2) {
if (link[d->len] == ':' && !memcmp(link, d->str, d->len)) {
kid = strtoul(&link[d->len + 2], &end, 10);
if (end && *end == ']')
BUG_ON(kid > UINT_MAX);
else
kid = 0;
}
}
return (unsigned int)kid;
}
bool check_ns_proc(struct fd_link *link)
{
unsigned int i, kid;
for (i = 0; i < ARRAY_SIZE(ns_desc_array); i++) {
kid = parse_ns_link(link->name + 1, link->len - 1, ns_desc_array[i]);
if (!kid)
continue;
link->ns_d = ns_desc_array[i];
link->ns_kid = kid;
return true;
}
return false;
}
int switch_ns(int pid, struct ns_desc *nd, int *rst)
{
char buf[32];
int nsfd;
int ret = -1;
nsfd = open_proc(pid, "ns/%s", nd->str);
if (nsfd < 0) {
pr_perror("Can't open ipcns file");
goto err_ns;
}
if (rst) {
snprintf(buf, sizeof(buf), "/proc/self/ns/%s", nd->str);
*rst = open(buf, O_RDONLY);
if (*rst < 0) {
pr_perror("Can't open ns file");
goto err_rst;
}
}
ret = setns(nsfd, nd->cflag);
if (ret < 0) {
pr_perror("Can't setns %d/%s", pid, nd->str);
goto err_set;
}
close(nsfd);
return 0;
err_set:
if (rst)
close(*rst);
err_rst:
close(nsfd);
err_ns:
return -1;
}
int restore_ns(int rst, struct ns_desc *nd)
{
int ret;
ret = setns(rst, nd->cflag);
if (ret < 0)
pr_perror("Can't restore ns back");
close(rst);
return ret;
}
struct ns_id *ns_ids = NULL;
static unsigned int ns_next_id = 1;
unsigned long root_ns_mask = 0;
static void nsid_add(struct ns_id *ns, struct ns_desc *nd, unsigned int id, pid_t pid)
{
ns->nd = nd;
ns->id = id;
ns->ns_pid = pid;
ns->next = ns_ids;
ns_ids = ns;
pr_info("Add %s ns %d pid %d\n", nd->str, ns->id, ns->ns_pid);
}
static struct ns_id *__rst_new_ns_id(unsigned int id, pid_t pid,
struct ns_desc *nd, enum ns_type type)
{
struct ns_id *nsid;
nsid = shmalloc(sizeof(*nsid));
if (nsid) {
nsid->type = type;
nsid_add(nsid, nd, id, pid);
futex_set(&nsid->ns_populated, 0);
}
return nsid;
}
struct ns_id *rst_new_ns_id(unsigned int id, pid_t pid, struct ns_desc *nd)
{
return __rst_new_ns_id(id, pid, nd, NS_CRIU);
}
int rst_add_ns_id(unsigned int id, struct pstree_item *i, struct ns_desc *nd)
{
pid_t pid = i->pid.virt;
struct ns_id *nsid;
nsid = lookup_ns_by_id(id, nd);
if (nsid) {
if (pid_rst_prio(pid, nsid->ns_pid))
nsid->ns_pid = pid;
return 0;
}
nsid = __rst_new_ns_id(id, pid, nd,
i == root_item ? NS_ROOT : NS_OTHER);
if (nsid == NULL)
return -1;
return 0;
}
static struct ns_id *lookup_ns_by_kid(unsigned int kid, struct ns_desc *nd)
{
struct ns_id *nsid;
for (nsid = ns_ids; nsid != NULL; nsid = nsid->next)
if (nsid->kid == kid && nsid->nd == nd)
return nsid;
return NULL;
}
struct ns_id *lookup_ns_by_id(unsigned int id, struct ns_desc *nd)
{
struct ns_id *nsid;
for (nsid = ns_ids; nsid != NULL; nsid = nsid->next)
if (nsid->id == id && nsid->nd == nd)
return nsid;
return NULL;
}
/*
* For all namespaces we support, there are two supported
* tasks-to-namespaces layout.
*
* If root task lives in the same namespace as criu does
* all other tasks should live in it too and we do NOT dump
* this namespace. On restore tasks inherit the respective
* namespace from criu.
*
* If root task lives in its own namespace, then all other
* tasks may live in it. Sometimes (CLONE_SUBNS) there can
* be more than one namespace of that type. For this case
* we dump all namespace's info and recreate them on restore.
*/
int walk_namespaces(struct ns_desc *nd, int (*cb)(struct ns_id *, void *), void *oarg)
{
int ret = 0;
struct ns_id *ns;
for (ns = ns_ids; ns != NULL; ns = ns->next) {
if (ns->nd != nd)
continue;
if (ns->type == NS_CRIU) {
if (root_ns_mask & nd->cflag)
continue;
ret = cb(ns, oarg);
break;
}
ret = cb(ns, oarg);
if (ret)
break;
}
return ret;
}
static unsigned int generate_ns_id(int pid, unsigned int kid, struct ns_desc *nd,
struct ns_id **ns_ret)
{
struct ns_id *nsid;
enum ns_type type;
nsid = lookup_ns_by_kid(kid, nd);
if (nsid)
goto found;
if (pid != getpid()) {
type = NS_OTHER;
if (pid == root_item->pid.real) {
BUG_ON(root_ns_mask & nd->cflag);
pr_info("Will take %s namespace in the image\n", nd->str);
root_ns_mask |= nd->cflag;
type = NS_ROOT;
} else if (nd->cflag & ~CLONE_SUBNS) {
pr_err("Can't dump nested %s namespace for %d\n",
nd->str, pid);
return 0;
}
} else
type = NS_CRIU;
nsid = xmalloc(sizeof(*nsid));
if (!nsid)
return 0;
nsid->type = type;
nsid->kid = kid;
futex_set(&nsid->ns_populated, 1);
nsid_add(nsid, nd, ns_next_id++, pid);
found:
if (ns_ret)
*ns_ret = nsid;
return nsid->id;
}
static unsigned int __get_ns_id(int pid, struct ns_desc *nd, struct ns_id **ns)
{
int proc_dir, ret;
unsigned int kid;
char ns_path[10], ns_id[32];
proc_dir = open_pid_proc(pid);
if (proc_dir < 0)
return 0;
sprintf(ns_path, "ns/%s", nd->str);
ret = readlinkat(proc_dir, ns_path, ns_id, sizeof(ns_id) - 1);
if (ret < 0) {
if (errno == ENOENT) {
/* The namespace is unsupported */
kid = 0;
goto out;
}
pr_perror("Can't readlink ns link");
return 0;
}
ns_id[ret] = '\0';
kid = parse_ns_link(ns_id, ret, nd);
BUG_ON(!kid);
out:
return generate_ns_id(pid, kid, nd, ns);
}
static unsigned int get_ns_id(int pid, struct ns_desc *nd)
{
return __get_ns_id(pid, nd, NULL);
}
int dump_one_ns_file(int lfd, u32 id, const struct fd_parms *p)
{
struct cr_img *img = img_from_set(glob_imgset, CR_FD_NS_FILES);
NsFileEntry nfe = NS_FILE_ENTRY__INIT;
struct fd_link *link = p->link;
struct ns_id *nsid;
nsid = lookup_ns_by_kid(link->ns_kid, link->ns_d);
if (!nsid) {
pr_err("No NS ID with kid %u\n", link->ns_kid);
return -1;
}
nfe.id = id;
nfe.ns_id = nsid->id;
nfe.ns_cflag = link->ns_d->cflag;
nfe.flags = p->flags;
return pb_write_one(img, &nfe, PB_NS_FILE);
}
const struct fdtype_ops nsfile_dump_ops = {
.type = FD_TYPES__NS,
.dump = dump_one_ns_file,
};
struct ns_file_info {
struct file_desc d;
NsFileEntry *nfe;
};
static int open_ns_fd(struct file_desc *d)
{
struct ns_file_info *nfi = container_of(d, struct ns_file_info, d);
struct pstree_item *item, *t;
struct ns_desc *nd = NULL;
char path[64];
int fd;
/*
* Find out who can open us.
*
* FIXME I need a hash or RBtree here.
*/
for_each_pstree_item(t) {
TaskKobjIdsEntry *ids = t->ids;
if (ids->pid_ns_id == nfi->nfe->ns_id) {
item = t;
nd = &pid_ns_desc;
break;
} else if (ids->net_ns_id == nfi->nfe->ns_id) {
item = t;
nd = &net_ns_desc;
break;
} else if (ids->ipc_ns_id == nfi->nfe->ns_id) {
item = t;
nd = &ipc_ns_desc;
break;
} else if (ids->uts_ns_id == nfi->nfe->ns_id) {
item = t;
nd = &uts_ns_desc;
break;
} else if (ids->mnt_ns_id == nfi->nfe->ns_id) {
item = t;
nd = &mnt_ns_desc;
break;
}
}
if (!nd || !item) {
pr_err("Can't find suitable NS ID for %#x\n", nfi->nfe->ns_id);
return -1;
}
if (nd->cflag != nfi->nfe->ns_cflag) {
pr_err("Clone flag mismatch for %#x\n", nfi->nfe->ns_id);
return -1;
}
snprintf(path, sizeof(path) - 1, "/proc/%d/ns/%s", item->pid.virt, nd->str);
path[sizeof(path) - 1] = '\0';
fd = open(path, nfi->nfe->flags);
if (fd < 0) {
pr_perror("Can't open file %s on restore", path);
return fd;
}
return fd;
}
static struct file_desc_ops ns_desc_ops = {
.type = FD_TYPES__NS,
.open = open_ns_fd,
};
static int collect_one_nsfile(void *o, ProtobufCMessage *base)
{
struct ns_file_info *nfi = o;
nfi->nfe = pb_msg(base, NsFileEntry);
pr_info("Collected ns file ID %#x NS-ID %#x\n", nfi->nfe->id, nfi->nfe->ns_id);
return file_desc_add(&nfi->d, nfi->nfe->id, &ns_desc_ops);
}
struct collect_image_info nsfile_cinfo = {
.fd_type = CR_FD_NS_FILES,
.pb_type = PB_NS_FILE,
.priv_size = sizeof(struct ns_file_info),
.collect = collect_one_nsfile,
};
/*
* Same as dump_task_ns_ids(), but
* a) doesn't keep IDs (don't need them)
* b) generates them for mount and netns only
* mnt ones are needed for open_mount() in
* inotify pred-dump
* net ones are needed for parasite socket
*/
int predump_task_ns_ids(struct pstree_item *item)
{
int pid = item->pid.real;
if (!__get_ns_id(pid, &net_ns_desc, &dmpi(item)->netns))
return -1;
if (!get_ns_id(pid, &mnt_ns_desc))
return -1;
return 0;
}
int dump_task_ns_ids(struct pstree_item *item)
{
int pid = item->pid.real;
TaskKobjIdsEntry *ids = item->ids;
ids->has_pid_ns_id = true;
ids->pid_ns_id = get_ns_id(pid, &pid_ns_desc);
if (!ids->pid_ns_id) {
pr_err("Can't make pidns id\n");
return -1;
}
ids->has_net_ns_id = true;
ids->net_ns_id = __get_ns_id(pid, &net_ns_desc, &dmpi(item)->netns);
if (!ids->net_ns_id) {
pr_err("Can't make netns id\n");
return -1;
}
ids->has_ipc_ns_id = true;
ids->ipc_ns_id = get_ns_id(pid, &ipc_ns_desc);
if (!ids->ipc_ns_id) {
pr_err("Can't make ipcns id\n");
return -1;
}
ids->has_uts_ns_id = true;
ids->uts_ns_id = get_ns_id(pid, &uts_ns_desc);
if (!ids->uts_ns_id) {
pr_err("Can't make utsns id\n");
return -1;
}
ids->has_mnt_ns_id = true;
ids->mnt_ns_id = get_ns_id(pid, &mnt_ns_desc);
if (!ids->mnt_ns_id) {
pr_err("Can't make mntns id\n");
return -1;
}
ids->has_user_ns_id = true;
ids->user_ns_id = get_ns_id(pid, &user_ns_desc);
if (!ids->user_ns_id) {
pr_err("Can't make userns id\n");
return -1;
}
return 0;
}
static UsernsEntry userns_entry = USERNS_ENTRY__INIT;
static int userns_id(int id, UidGidExtent **map, int n)
{
int i;
if (!(root_ns_mask & CLONE_NEWUSER))
return id;
for (i = 0; i < n; i++) {
if (map[i]->lower_first <= id &&
map[i]->lower_first + map[i]->count > id)
return map[i]->first + (id - map[i]->lower_first);
}
return -1;
}
int userns_uid(int uid)
{
UsernsEntry *e = &userns_entry;
return userns_id(uid, e->uid_map, e->n_uid_map);
}
int userns_gid(int gid)
{
UsernsEntry *e = &userns_entry;
return userns_id(gid, e->gid_map, e->n_gid_map);
}
static int parse_id_map(pid_t pid, char *name, UidGidExtent ***pb_exts)
{
UidGidExtent *extents = NULL;
int len = 0, size = 0, ret, i;
FILE *f;
f = fopen_proc(pid, "%s", name);
if (f == NULL)
return -1;
ret = -1;
while (1) {
UidGidExtent *ext;
if (len == size) {
UidGidExtent *t;
size = size * 2 + 1;
t = xrealloc(extents, size * sizeof(UidGidExtent));
if (t == NULL)
break;
extents = t;
}
ext = &extents[len];
uid_gid_extent__init(ext);
ret = fscanf(f, "%d %d %d", &ext->first,
&ext->lower_first, &ext->count);
if (ret != 3) {
if (errno != 0) {
pr_perror("Unable to parse extents");
ret = -1;
} else
ret = 0;
break;
}
pr_info("id_map: %d %d %d\n", ext->first, ext->lower_first, ext->count);
len++;
}
fclose(f);
if (ret)
goto err;
if (len) {
*pb_exts = xmalloc(sizeof(UidGidExtent *) * len);
if (*pb_exts == NULL)
goto err;
for (i = 0; i < len; i++)
(*pb_exts)[i] = &extents[i];
} else {
xfree(extents);
*pb_exts = NULL;
}
return len;
err:
xfree(extents);
return -1;
}
int collect_user_ns(struct ns_id *ns, void *oarg)
{
/*
* User namespace is dumped before files to get uid and gid
* mappings, which are used for convirting local id-s to
* userns id-s (userns_uid(), userns_gid())
*/
if (dump_user_ns(root_item->pid.real, root_item->ids->user_ns_id))
return -1;
return 0;
}
int collect_user_namespaces(bool for_dump)
{
if (!for_dump)
return 0;
if (!(root_ns_mask & CLONE_NEWUSER))
return 0;
return walk_namespaces(&net_ns_desc, collect_user_ns, NULL);
}
static int check_user_ns(int pid)
{
int status;
pid_t chld;
chld = fork();
if (chld == -1) {
pr_perror("Unable to fork a process");
return -1;
}
if (chld == 0) {
/*
* Check that we are able to enter into other namespaces
* from the target userns namespace. This signs that these
* namespaces were created from the target userns.
*/
if (switch_ns(pid, &user_ns_desc, NULL))
exit(-1);
if ((root_ns_mask & CLONE_NEWNET) &&
switch_ns(pid, &net_ns_desc, NULL))
exit(-1);
if ((root_ns_mask & CLONE_NEWUTS) &&
switch_ns(pid, &uts_ns_desc, NULL))
exit(-1);
if ((root_ns_mask & CLONE_NEWIPC) &&
switch_ns(pid, &ipc_ns_desc, NULL))
exit(-1);
if ((root_ns_mask & CLONE_NEWNS) &&
switch_ns(pid, &mnt_ns_desc, NULL))
exit(-1);
exit(0);
}
if (waitpid(chld, &status, 0) != chld) {
pr_perror("Unable to wait the %d process", pid);
return -1;
}
if (status) {
pr_err("One or more namespaces doesn't belong to the target user namespace\n");
return -1;
}
return 0;
}
int dump_user_ns(pid_t pid, int ns_id)
{
int ret, exit_code = -1;
UsernsEntry *e = &userns_entry;
struct cr_img *img;
if (check_user_ns(pid))
return -1;
ret = parse_id_map(pid, "uid_map", &e->uid_map);
if (ret < 0)
goto err;
e->n_uid_map = ret;
ret = parse_id_map(pid, "gid_map", &e->gid_map);
if (ret < 0)
goto err;
e->n_gid_map = ret;
img = open_image(CR_FD_USERNS, O_DUMP, ns_id);
if (!img)
goto err;
ret = pb_write_one(img, e, PB_USERNS);
close_image(img);
if (ret < 0)
goto err;
return 0;
err:
if (e->uid_map) {
xfree(e->uid_map[0]);
xfree(e->uid_map);
}
if (e->gid_map) {
xfree(e->gid_map[0]);
xfree(e->gid_map);
}
return exit_code;
}
void free_userns_maps()
{
if (userns_entry.n_uid_map > 0) {
xfree(userns_entry.uid_map[0]);
xfree(userns_entry.uid_map);
}
if (userns_entry.n_gid_map > 0) {
xfree(userns_entry.gid_map[0]);
xfree(userns_entry.gid_map);
}
}
static int do_dump_namespaces(struct ns_id *ns)
{
int ret;
ret = switch_ns(ns->ns_pid, ns->nd, NULL);
if (ret)
return ret;
switch (ns->nd->cflag) {
case CLONE_NEWUTS:
pr_info("Dump UTS namespace %d via %d\n",
ns->id, ns->ns_pid);
ret = dump_uts_ns(ns->id);
break;
case CLONE_NEWIPC:
pr_info("Dump IPC namespace %d via %d\n",
ns->id, ns->ns_pid);
ret = dump_ipc_ns(ns->id);
break;
case CLONE_NEWNET:
pr_info("Dump NET namespace info %d via %d\n",
ns->id, ns->ns_pid);
ret = dump_net_ns(ns->id);
break;
default:
pr_err("Unknown namespace flag %x\n", ns->nd->cflag);
break;
}
return ret;
}
int dump_namespaces(struct pstree_item *item, unsigned int ns_flags)
{
struct pid *ns_pid = &item->pid;
struct ns_id *ns;
int pid, nr = 0;
int ret = 0;
/*
* The setns syscall is cool, we can switch to the other
* namespace and then return back to our initial one, but
* for me it's much easier just to fork another task and
* let it do the job, all the more so it can be done in
* parallel with task dumping routine.
*
* However, the question how to dump sockets from the target
* net namespace with this is still open
*/
pr_info("Dumping %d(%d)'s namespaces\n", ns_pid->virt, ns_pid->real);
if ((ns_flags & CLONE_NEWPID) && ns_pid->virt != 1) {
pr_err("Can't dump a pid namespace without the process init\n");
return -1;
}
for (ns = ns_ids; ns; ns = ns->next) {
/* Skip current namespaces, which are in the list too */
if (ns->type == NS_CRIU)
continue;
switch (ns->nd->cflag) {
/* No data for pid namespaces to dump */
case CLONE_NEWPID:
/* Dumped explicitly with dump_mnt_namespaces() */
case CLONE_NEWNS:
/* Userns is dumped before dumping tasks */
case CLONE_NEWUSER:
continue;
}
pid = fork();
if (pid < 0) {
pr_perror("Can't fork ns dumper");
return -1;
}
if (pid == 0) {
ret = do_dump_namespaces(ns);
exit(ret);
}
nr++;
}
while (nr > 0) {
int status;
ret = waitpid(-1, &status, 0);
if (ret < 0) {
pr_perror("Can't wait ns dumper");
return -1;
}
if (!WIFEXITED(status) || WEXITSTATUS(status) != 0) {
pr_err("Namespaces dumping finished with error %d\n", status);
return -1;
}
nr--;
}
pr_info("Namespaces dump complete\n");
return 0;
}
static int write_id_map(pid_t pid, UidGidExtent **extents, int n, char *id_map)
{
char buf[PAGE_SIZE];
int off = 0, i;
int fd;
/*
* We can perform only a single write (that may contain multiple
* newline-delimited records) to a uid_map and a gid_map files.
*/
for (i = 0; i < n; i++)
off += snprintf(buf + off, sizeof(buf) - off,
"%u %u %u\n", extents[i]->first,
extents[i]->lower_first,
extents[i]->count);
fd = open_proc_rw(pid, "%s", id_map);
if (fd < 0)
return -1;
if (write(fd, buf, off) != off) {
pr_perror("Unable to write into %s", id_map);
close(fd);
return -1;
}
close(fd);
return 0;
}
struct unsc_msg {
struct msghdr h;
/*
* 0th is the call address
* 1st is the flags
* 2nd is the optional (NULL in responce) arguments
*/
struct iovec iov[3];
char c[CMSG_SPACE(sizeof(struct ucred)) + CMSG_SPACE(sizeof(int))];
};
static int usernsd_pid;
static inline void unsc_msg_init(struct unsc_msg *m, uns_call_t *c,
int *x, void *arg, size_t asize, int fd)
{
struct cmsghdr *ch;
struct ucred *ucred;
m->h.msg_iov = m->iov;
m->h.msg_iovlen = 2;
m->iov[0].iov_base = c;
m->iov[0].iov_len = sizeof(*c);
m->iov[1].iov_base = x;
m->iov[1].iov_len = sizeof(*x);
if (arg) {
m->iov[2].iov_base = arg;
m->iov[2].iov_len = asize;
m->h.msg_iovlen++;
}
m->h.msg_name = NULL;
m->h.msg_namelen = 0;
m->h.msg_flags = 0;
m->h.msg_control = &m->c;
/* Need to memzero because of:
* https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=514917
*/
memzero(&m->c, sizeof(m->c));
m->h.msg_controllen = CMSG_SPACE(sizeof(struct ucred));
ch = CMSG_FIRSTHDR(&m->h);
ch->cmsg_len = CMSG_LEN(sizeof(struct ucred));
ch->cmsg_level = SOL_SOCKET;
ch->cmsg_type = SCM_CREDENTIALS;
ucred = (struct ucred *) CMSG_DATA(ch);
ucred->pid = getpid();
ucred->uid = getuid();
ucred->gid = getgid();
if (fd >= 0) {
m->h.msg_controllen += CMSG_SPACE(sizeof(int));
ch = CMSG_NXTHDR(&m->h, ch);
BUG_ON(!ch);
ch->cmsg_len = CMSG_LEN(sizeof(int));
ch->cmsg_level = SOL_SOCKET;
ch->cmsg_type = SCM_RIGHTS;
*((int *)CMSG_DATA(ch)) = fd;
}
}
static void unsc_msg_pid_fd(struct unsc_msg *um, pid_t *pid, int *fd)
{
struct cmsghdr *ch;
struct ucred *ucred;
ch = CMSG_FIRSTHDR(&um->h);
BUG_ON(!ch);
BUG_ON(ch->cmsg_len != CMSG_LEN(sizeof(struct ucred)));
BUG_ON(ch->cmsg_level != SOL_SOCKET);
BUG_ON(ch->cmsg_type != SCM_CREDENTIALS);
if (pid) {
ucred = (struct ucred *) CMSG_DATA(ch);
*pid = ucred->pid;
}
ch = CMSG_NXTHDR(&um->h, ch);
if (ch && ch->cmsg_len == CMSG_LEN(sizeof(int))) {
BUG_ON(ch->cmsg_level != SOL_SOCKET);
BUG_ON(ch->cmsg_type != SCM_RIGHTS);
*fd = *((int *)CMSG_DATA(ch));
} else {
*fd = -1;
}
}
static int usernsd(int sk)
{
pr_info("uns: Daemon started\n");
while (1) {
struct unsc_msg um;
static char msg[MAX_UNSFD_MSG_SIZE];
uns_call_t call;
int flags, fd, ret;
pid_t pid;
unsc_msg_init(&um, &call, &flags, msg, sizeof(msg), 0);
if (recvmsg(sk, &um.h, 0) <= 0) {
pr_perror("uns: recv req error");
return -1;
}
unsc_msg_pid_fd(&um, &pid, &fd);
pr_debug("uns: daemon calls %p (%d, %d, %x)\n", call, pid, fd, flags);
BUG_ON(fd < 0 && flags & UNS_FDOUT);
/*
* Caller has sent us bare address of the routine it
* wants to call. Since the caller is fork()-ed from the
* same process as the daemon is, the latter has exactly
* the same code at exactly the same address as the
* former guy has. So go ahead and just call one!
*/
ret = call(msg, fd, pid);
if (fd >= 0)
close(fd);
if (flags & UNS_ASYNC) {
/*
* Async call failed and the called doesn't know
* about it. Exit now and let the stop_usernsd()
* check the exit code and abort the restoration.
*
* We'd get there either by the end of restore or
* from the next userns_call() due to failed
* sendmsg() in there.
*/
if (ret < 0) {
pr_err("uns: Async call failed. Exiting\n");
return -1;
}
continue;