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files-reg.c
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files-reg.c
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#include <stdlib.h>
#include <unistd.h>
#include <errno.h>
#include <fcntl.h>
#include <string.h>
#include <sys/mman.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/vfs.h>
#include <sys/prctl.h>
#include <ctype.h>
#include <sched.h>
/* Stolen from kernel/fs/nfs/unlink.c */
#define SILLYNAME_PREF ".nfs"
#define SILLYNAME_SUFF_LEN (((unsigned)sizeof(u64) << 1) + ((unsigned)sizeof(unsigned int) << 1))
#include "cr_options.h"
#include "imgset.h"
#include "file-ids.h"
#include "mount.h"
#include "files.h"
#include "list.h"
#include "rst-malloc.h"
#include "fs-magic.h"
#include "asm/atomic.h"
#include "namespaces.h"
#include "proc_parse.h"
#include "pstree.h"
#include "fault-injection.h"
#include "protobuf.h"
#include "images/regfile.pb-c.h"
#include "images/remap-file-path.pb-c.h"
#include "files-reg.h"
#include "plugin.h"
int setfsuid(uid_t fsuid);
/*
* Ghost files are those not visible from the FS. Dumping them is
* nasty and the only way we have -- just carry its contents with
* us. Any brave soul to implement link unlinked file back?
*/
struct ghost_file {
struct list_head list;
u32 id;
u32 dev;
u32 ino;
struct file_remap remap;
};
static u32 ghost_file_ids = 1;
static LIST_HEAD(ghost_files);
static mutex_t *ghost_file_mutex;
static LIST_HEAD(remaps);
/*
* Remember the name to delete it if needed on error or
* rollback action. Note we don't expect that there will
* be a HUGE number of link remaps, so in a sake of speed
* we keep all data in memory.
*/
struct link_remap_rlb {
struct list_head list;
struct ns_id *mnt_ns;
char *path;
};
static int note_link_remap(char *path, struct ns_id *nsid)
{
struct link_remap_rlb *rlb;
rlb = xmalloc(sizeof(*rlb));
if (!rlb)
goto err;
rlb->path = strdup(path);
if (!rlb->path)
goto err2;
rlb->mnt_ns = nsid;
list_add(&rlb->list, &remaps);
return 0;
err2:
xfree(rlb);
err:
pr_err("Can't note link remap for %s\n", path);
return -1;
}
/* Trim "a/b/c/d" to "a/b/d" */
static int trim_last_parent(char *path)
{
char *fname, *p;
p = strrchr(path, '/');
fname = p + 1;
if (!p || *fname == '\0')
return -1;
while (p >= path && *p == '/')
p--;
if (p < path)
return -1;
while (p >= path && *p != '/')
p--;
p++;
while (*fname != '\0')
*p++ = *fname++;
*p = '\0';
return 0;
}
static int mkreg_ghost(char *path, u32 mode, struct ghost_file *gf, struct cr_img *img)
{
int gfd, ret;
gfd = open(path, O_WRONLY | O_CREAT | O_EXCL, mode);
if (gfd < 0)
return -1;
ret = copy_file(img_raw_fd(img), gfd, 0);
if (ret < 0)
unlink(path);
close(gfd);
return ret;
}
static int ghost_apply_metadata(const char *path, GhostFileEntry *gfe)
{
struct timeval tv[2];
int ret = -1;
if (chown(path, gfe->uid, gfe->gid) < 0) {
pr_perror("Can't reset user/group on ghost %s", path);
goto err;
}
if (chmod(path, gfe->mode)) {
pr_perror("Can't set perms %o on ghost %s", gfe->mode, path);
goto err;
}
if (gfe->atim) {
tv[0].tv_sec = gfe->atim->tv_sec;
tv[0].tv_usec = gfe->atim->tv_usec;
tv[1].tv_sec = gfe->mtim->tv_sec;
tv[1].tv_usec = gfe->mtim->tv_usec;
if (lutimes(path, tv)) {
pr_perror("Can't set access and modufication times on ghost %s", path);
goto err;
}
}
ret = 0;
err:
return ret;
}
static int create_ghost(struct ghost_file *gf, GhostFileEntry *gfe, struct cr_img *img)
{
char path[PATH_MAX];
int ret, root_len;
char *msg;
root_len = ret = rst_get_mnt_root(gf->remap.rmnt_id, path, sizeof(path));
if (ret < 0) {
pr_err("The %d mount is not found for ghost\n", gf->remap.rmnt_id);
goto err;
}
snprintf(path + ret, sizeof(path) - ret, "/%s", gf->remap.rpath);
ret = -1;
again:
if (S_ISFIFO(gfe->mode)) {
if ((ret = mknod(path, gfe->mode, 0)) < 0)
msg = "Can't create node for ghost file";
} else if (S_ISCHR(gfe->mode) || S_ISBLK(gfe->mode)) {
if (!gfe->has_rdev) {
pr_err("No rdev for ghost device\n");
goto err;
}
if ((ret = mknod(path, gfe->mode, gfe->rdev)) < 0)
msg = "Can't create node for ghost dev";
} else if (S_ISDIR(gfe->mode)) {
if ((ret = mkdir(path, gfe->mode)) < 0) {
pr_perror("Can't make ghost dir");
goto err;
}
} else {
if ((ret = mkreg_ghost(path, gfe->mode, gf, img)) < 0)
msg = "Can't create ghost regfile";
}
if (ret < 0) {
/* Use grand parent, if parent directory does not exist */
if (errno == ENOENT) {
if (trim_last_parent(path) < 0) {
pr_err("trim failed: @%s@\n", path);
goto err;
}
goto again;
}
pr_perror("%s", msg);
goto err;
}
strcpy(gf->remap.rpath, path + root_len + 1);
pr_debug("Remap rpath is %s\n", gf->remap.rpath);
ret = -1;
if (ghost_apply_metadata(path, gfe))
goto err;
ret = 0;
err:
return ret;
}
static inline void ghost_path(char *path, int plen,
struct reg_file_info *rfi, RemapFilePathEntry *rfe)
{
snprintf(path, plen, "%s.cr.%x.ghost", rfi->path, rfe->remap_id);
}
static int open_remap_ghost(struct reg_file_info *rfi,
RemapFilePathEntry *rfe)
{
struct ghost_file *gf;
GhostFileEntry *gfe = NULL;
struct cr_img *img;
list_for_each_entry(gf, &ghost_files, list)
if (gf->id == rfe->remap_id)
goto gf_found;
/*
* Ghost not found. We will create one in the same dir
* as the very first client of it thus resolving any
* issues with cross-device links.
*/
pr_info("Opening ghost file %#x for %s\n", rfe->remap_id, rfi->path);
gf = shmalloc(sizeof(*gf));
if (!gf)
return -1;
gf->remap.rpath = xmalloc(PATH_MAX);
if (!gf->remap.rpath)
goto err;
img = open_image(CR_FD_GHOST_FILE, O_RSTR, rfe->remap_id);
if (!img)
goto err;
if (pb_read_one(img, &gfe, PB_GHOST_FILE) < 0)
goto close_ifd;
/*
* For old formats where optional has_[dev|ino] is
* not present we will have zeros here which is quite
* a sign for "absent" fields.
*/
gf->dev = gfe->dev;
gf->ino = gfe->ino;
gf->remap.rmnt_id = rfi->rfe->mnt_id;
if (S_ISDIR(gfe->mode))
strncpy(gf->remap.rpath, rfi->path, PATH_MAX);
else
ghost_path(gf->remap.rpath, PATH_MAX, rfi, rfe);
if (create_ghost(gf, gfe, img))
goto close_ifd;
ghost_file_entry__free_unpacked(gfe, NULL);
close_image(img);
gf->id = rfe->remap_id;
gf->remap.users = 0;
gf->remap.is_dir = S_ISDIR(gfe->mode);
gf->remap.owner = gfe->uid;
list_add_tail(&gf->list, &ghost_files);
gf_found:
rfi->is_dir = gf->remap.is_dir;
rfi->remap = &gf->remap;
return 0;
close_ifd:
close_image(img);
err:
if (gfe)
ghost_file_entry__free_unpacked(gfe, NULL);
xfree(gf->remap.rpath);
shfree_last(gf);
return -1;
}
static int open_remap_linked(struct reg_file_info *rfi,
RemapFilePathEntry *rfe)
{
struct file_remap *rm;
struct file_desc *rdesc;
struct reg_file_info *rrfi;
uid_t owner = -1;
rdesc = find_file_desc_raw(FD_TYPES__REG, rfe->remap_id);
if (!rdesc) {
pr_err("Can't find target file %x\n", rfe->remap_id);
return -1;
}
rm = xmalloc(sizeof(*rm));
if (!rm)
return -1;
rrfi = container_of(rdesc, struct reg_file_info, d);
pr_info("Remapped %s -> %s\n", rfi->path, rrfi->path);
if (root_ns_mask & CLONE_NEWUSER) {
int rfd;
struct stat st;
rfd = mntns_get_root_by_mnt_id(rfi->rfe->mnt_id);
if (fstatat(rfd, rrfi->path, &st, AT_SYMLINK_NOFOLLOW)) {
pr_perror("Can't get owner of link remap %s", rrfi->path);
xfree(rm);
return -1;
}
owner = st.st_uid;
}
rm->rpath = rrfi->path;
rm->users = 0;
rm->is_dir = false;
rm->owner = owner;
rm->rmnt_id = rfi->rfe->mnt_id;
rfi->remap = rm;
return 0;
}
static int open_remap_dead_process(struct reg_file_info *rfi,
RemapFilePathEntry *rfe)
{
struct pstree_item *helper;
helper = lookup_create_item(rfe->remap_id);
if (!helper)
return -1;
if (helper->pid.state != TASK_UNDEF) {
pr_info("Skipping helper for restoring /proc/%d; pid exists\n", rfe->remap_id);
return 0;
}
init_pstree_helper(helper);
helper->sid = root_item->sid;
helper->pgid = root_item->pgid;
helper->pid.virt = rfe->remap_id;
helper->parent = root_item;
list_add_tail(&helper->sibling, &root_item->children);
pr_info("Added a helper for restoring /proc/%d\n", helper->pid.virt);
return 0;
}
struct remap_info {
struct list_head list;
RemapFilePathEntry *rfe;
struct reg_file_info *rfi;
};
static int collect_one_remap(void *obj, ProtobufCMessage *msg, struct cr_img *i)
{
struct remap_info *ri = obj;
RemapFilePathEntry *rfe;
struct file_desc *fdesc;
ri->rfe = rfe = pb_msg(msg, RemapFilePathEntry);
if (!rfe->has_remap_type) {
rfe->has_remap_type = true;
/* backward compatibility with images */
if (rfe->remap_id & REMAP_GHOST) {
rfe->remap_id &= ~REMAP_GHOST;
rfe->remap_type = REMAP_TYPE__GHOST;
} else
rfe->remap_type = REMAP_TYPE__LINKED;
}
fdesc = find_file_desc_raw(FD_TYPES__REG, rfe->orig_id);
if (fdesc == NULL) {
pr_err("Remap for non existing file %#x\n", rfe->orig_id);
return -1;
}
ri->rfi = container_of(fdesc, struct reg_file_info, d);
list_add_tail(&ri->list, &remaps);
return 0;
}
static int prepare_one_remap(struct remap_info *ri)
{
int ret = -1;
RemapFilePathEntry *rfe = ri->rfe;
struct reg_file_info *rfi = ri->rfi;
pr_info("Configuring remap %#x -> %#x\n", rfi->rfe->id, rfe->remap_id);
switch (rfe->remap_type) {
case REMAP_TYPE__LINKED:
ret = open_remap_linked(rfi, rfe);
break;
case REMAP_TYPE__GHOST:
ret = open_remap_ghost(rfi, rfe);
break;
case REMAP_TYPE__PROCFS:
/* handled earlier by prepare_procfs_remaps */
ret = 0;
break;
default:
pr_err("unknown remap type %u\n", rfe->remap_type);
goto out;
}
out:
return ret;
}
/* We separate the preparation of PROCFS remaps because they allocate pstree
* items, which need to be seen by the root task. We can't do all remaps here,
* because the files haven't been loaded yet.
*/
int prepare_procfs_remaps(void)
{
struct remap_info *ri;
list_for_each_entry(ri, &remaps, list) {
RemapFilePathEntry *rfe = ri->rfe;
struct reg_file_info *rfi = ri->rfi;
switch (rfe->remap_type) {
case REMAP_TYPE__PROCFS:
if (open_remap_dead_process(rfi, rfe) < 0)
return -1;
break;
default:
continue;
}
}
return 0;
}
int prepare_remaps(void)
{
struct remap_info *ri;
int ret = 0;
list_for_each_entry(ri, &remaps, list) {
ret = prepare_one_remap(ri);
if (ret)
break;
}
return ret;
}
static void try_clean_ghost(struct remap_info *ri)
{
char path[PATH_MAX];
int mnt_id, ret;
mnt_id = ri->rfi->rfe->mnt_id; /* rirfirfe %) */
ret = rst_get_mnt_root(mnt_id, path, sizeof(path));
if (ret < 0)
return;
if (ret >= sizeof(path) - 1) {
pr_err("The path buffer is too small\n");
return;
}
if (path[ret] != '/') {
path[ret++] = '/';
path[ret] = 0;
}
if (ri->rfi->remap == NULL)
return;
if (!ri->rfi->is_dir) {
ghost_path(path + ret, sizeof(path) - ret, ri->rfi, ri->rfe);
if (!unlink(path)) {
pr_info(" `- X [%s] ghost\n", path);
return;
}
} else {
strncpy(path + ret, ri->rfi->path, sizeof(path) - ret);
if (!rmdir(path)) {
pr_info(" `- Xd [%s] ghost\n", path);
return;
}
}
pr_perror(" `- XFail [%s] ghost", path);
}
static int clean_one_remap(struct file_remap *remap)
{
int rmntns_root, ret = 0;
rmntns_root = mntns_get_root_by_mnt_id(remap->rmnt_id);
if (rmntns_root < 0)
return -1;
pr_info("Unlink remap %s\n", remap->rpath);
ret = unlinkat(rmntns_root, remap->rpath, remap->is_dir ? AT_REMOVEDIR : 0);
if (ret < 0) {
pr_perror("Couldn't unlink remap %s", remap->rpath);
return -1;
}
return 0;
}
void try_clean_remaps()
{
struct remap_info *ri;
if (list_empty(&remaps))
return;
list_for_each_entry(ri, &remaps, list)
if (ri->rfe->remap_type == REMAP_TYPE__GHOST)
try_clean_ghost(ri);
}
static struct collect_image_info remap_cinfo = {
.fd_type = CR_FD_REMAP_FPATH,
.pb_type = PB_REMAP_FPATH,
.priv_size = sizeof(struct remap_info),
.collect = collect_one_remap,
};
static int dump_ghost_file(int _fd, u32 id, const struct stat *st, dev_t phys_dev)
{
struct cr_img *img;
GhostFileEntry gfe = GHOST_FILE_ENTRY__INIT;
Timeval atim = TIMEVAL__INIT, mtim = TIMEVAL__INIT;
pr_info("Dumping ghost file contents (id %#x)\n", id);
img = open_image(CR_FD_GHOST_FILE, O_DUMP, id);
if (!img)
return -1;
gfe.uid = userns_uid(st->st_uid);
gfe.gid = userns_gid(st->st_gid);
gfe.mode = st->st_mode;
gfe.atim = &atim;
gfe.mtim = &mtim;
gfe.atim->tv_sec = st->st_atim.tv_sec;
gfe.atim->tv_usec = st->st_atim.tv_nsec / 1000;
gfe.mtim->tv_sec = st->st_mtim.tv_sec;
gfe.mtim->tv_usec = st->st_mtim.tv_nsec / 1000;
gfe.has_dev = gfe.has_ino = true;
gfe.dev = phys_dev;
gfe.ino = st->st_ino;
if (S_ISCHR(st->st_mode) || S_ISBLK(st->st_mode)) {
gfe.has_rdev = true;
gfe.rdev = st->st_rdev;
}
if (pb_write_one(img, &gfe, PB_GHOST_FILE))
return -1;
if (S_ISREG(st->st_mode)) {
int fd, ret;
char lpath[PSFDS];
/*
* Reopen file locally since it may have no read
* permissions when drained
*/
sprintf(lpath, "/proc/self/fd/%d", _fd);
fd = open(lpath, O_RDONLY);
if (fd < 0) {
pr_perror("Can't open ghost original file");
return -1;
}
ret = copy_file(fd, img_raw_fd(img), st->st_size);
close(fd);
if (ret)
return -1;
}
close_image(img);
return 0;
}
void remap_put(struct file_remap *remap)
{
mutex_lock(ghost_file_mutex);
if (--remap->users == 0)
clean_one_remap(remap);
mutex_unlock(ghost_file_mutex);
}
struct file_remap *lookup_ghost_remap(u32 dev, u32 ino)
{
struct ghost_file *gf;
mutex_lock(ghost_file_mutex);
list_for_each_entry(gf, &ghost_files, list) {
if (gf->ino == ino && (gf->dev == dev)) {
gf->remap.users++;
mutex_unlock(ghost_file_mutex);
return &gf->remap;
}
}
mutex_unlock(ghost_file_mutex);
return NULL;
}
static int dump_ghost_remap(char *path, const struct stat *st,
int lfd, u32 id, struct ns_id *nsid)
{
struct ghost_file *gf;
RemapFilePathEntry rpe = REMAP_FILE_PATH_ENTRY__INIT;
dev_t phys_dev;
pr_info("Dumping ghost file for fd %d id %#x\n", lfd, id);
if (st->st_size > opts.ghost_limit) {
pr_err("Can't dump ghost file %s of %"PRIu64" size, increase limit\n",
path, st->st_size);
return -1;
}
phys_dev = phys_stat_resolve_dev(nsid, st->st_dev, path);
list_for_each_entry(gf, &ghost_files, list)
if ((gf->dev == phys_dev) && (gf->ino == st->st_ino))
goto dump_entry;
gf = xmalloc(sizeof(*gf));
if (gf == NULL)
return -1;
gf->dev = phys_dev;
gf->ino = st->st_ino;
gf->id = ghost_file_ids++;
list_add_tail(&gf->list, &ghost_files);
if (dump_ghost_file(lfd, gf->id, st, phys_dev))
return -1;
dump_entry:
rpe.orig_id = id;
rpe.remap_id = gf->id;
rpe.has_remap_type = true;
rpe.remap_type = REMAP_TYPE__GHOST;
return pb_write_one(img_from_set(glob_imgset, CR_FD_REMAP_FPATH),
&rpe, PB_REMAP_FPATH);
}
static void __rollback_link_remaps(bool do_unlink)
{
struct link_remap_rlb *rlb, *tmp;
int mntns_root;
list_for_each_entry_safe(rlb, tmp, &remaps, list) {
if (do_unlink) {
mntns_root = mntns_get_root_fd(rlb->mnt_ns);
if (mntns_root >= 0)
unlinkat(mntns_root, rlb->path, 0);
else
pr_err("Failed to clenaup %s link remap\n", rlb->path);
}
list_del(&rlb->list);
xfree(rlb->path);
xfree(rlb);
}
}
void delete_link_remaps(void) { __rollback_link_remaps(true); }
void free_link_remaps(void) { __rollback_link_remaps(false); }
static int create_link_remap(char *path, int len, int lfd,
u32 *idp, struct ns_id *nsid)
{
char link_name[PATH_MAX], *tmp;
RegFileEntry rfe = REG_FILE_ENTRY__INIT;
FownEntry fwn = FOWN_ENTRY__INIT;
int mntns_root;
int ret;
if (!opts.link_remap_ok) {
pr_err("Can't create link remap for %s. "
"Use " LREMAP_PARAM " option.\n", path);
return -1;
}
/*
* Linked remapping -- we create a hard link on a removed file
* in the directory original file used to sit.
*
* Bad news is than we can't easily open lfd's parent dir. Thus
* we have to just generate an absolute path and use it. The linkat
* will fail if we chose the bad one.
*/
link_name[0] = '.';
memcpy(link_name + 1, path, len);
tmp = link_name + len;
while (*tmp != '/') {
BUG_ON(tmp == link_name);
tmp--;
}
fd_id_generate_special(NULL, idp);
rfe.id = *idp;
rfe.flags = 0;
rfe.pos = 0;
rfe.fown = &fwn;
rfe.name = link_name + 1;
/* Any 'unique' name works here actually. Remap works by reg-file ids. */
snprintf(tmp + 1, sizeof(link_name) - (size_t)(tmp - link_name - 1), "link_remap.%d", rfe.id);
mntns_root = mntns_get_root_fd(nsid);
again:
ret = linkat(lfd, "", mntns_root, link_name, AT_EMPTY_PATH);
if (ret < 0 && errno == ENOENT) {
/* Use grand parent, if parent directory does not exist. */
if (trim_last_parent(link_name) < 0) {
pr_err("trim failed: @%s@\n", link_name);
return -1;
}
goto again;
} else if (ret < 0) {
pr_perror("Can't link remap to %s", path);
return -1;
}
if (note_link_remap(link_name, nsid))
return -1;
return pb_write_one(img_from_set(glob_imgset, CR_FD_REG_FILES), &rfe, PB_REG_FILE);
}
static int dump_linked_remap(char *path, int len, const struct stat *ost,
int lfd, u32 id, struct ns_id *nsid)
{
u32 lid;
RemapFilePathEntry rpe = REMAP_FILE_PATH_ENTRY__INIT;
if (create_link_remap(path, len, lfd, &lid, nsid))
return -1;
rpe.orig_id = id;
rpe.remap_id = lid;
return pb_write_one(img_from_set(glob_imgset, CR_FD_REMAP_FPATH),
&rpe, PB_REMAP_FPATH);
}
static pid_t *dead_pids;
static int n_dead_pids;
int dead_pid_conflict(void)
{
int i;
for (i = 0; i < n_dead_pids; i++) {
struct pid *node;
pid_t pid = dead_pids[i];
node = pstree_pid_by_virt(pid);
if (!node)
continue;
if (node->state != TASK_THREAD) {
struct pstree_item *item;
/*
* If the dead PID was given to a main thread of another
* process, this is handled during restore.
*/
item = container_of(node, struct pstree_item, pid);
if (item->pid.real == item->threads[i].real ||
item->threads[i].virt != pid)
continue;
}
pr_err("Conflict with a dead task with the same PID as of this thread (virt %d, real %d).\n",
node->virt, node->real);
return -1;
}
return 0;
}
static int have_seen_dead_pid(pid_t pid)
{
int i;
for (i = 0; i < n_dead_pids; i++) {
if (dead_pids[i] == pid)
return 1;
}
if (xrealloc_safe(&dead_pids, sizeof(*dead_pids) * (n_dead_pids + 1)))
return -1;
dead_pids[n_dead_pids++] = pid;
return 0;
}
static int dump_dead_process_remap(pid_t pid, u32 id)
{
RemapFilePathEntry rpe = REMAP_FILE_PATH_ENTRY__INIT;
int ret;
ret = have_seen_dead_pid(pid);
if (ret < 0)
return -1;
if (ret) {
pr_info("Found dead pid %d already, skipping remap\n", pid);
return 0;
}
rpe.orig_id = id;
rpe.remap_id = pid;
rpe.has_remap_type = true;
rpe.remap_type = REMAP_TYPE__PROCFS;
return pb_write_one(img_from_set(glob_imgset, CR_FD_REMAP_FPATH),
&rpe, PB_REMAP_FPATH);
}
static bool is_sillyrename_name(char *name)
{
int i;
name = strrchr(name, '/');
BUG_ON(name == NULL); /* see check in dump_one_reg_file */
name++;
/*
* Strictly speaking this check is not bullet-proof. User
* can create file with this name by hands and we have no
* API to distinguish really-silly-renamed files from those
* fake names :(
*
* But since NFS people expect .nfsXXX files to be unstable,
* we treat them as such too.
*/
if (strncmp(name, SILLYNAME_PREF, sizeof(SILLYNAME_PREF) - 1))
return false;
name += sizeof(SILLYNAME_PREF) - 1;
for (i = 0; i < SILLYNAME_SUFF_LEN; i++)
if (!isxdigit(name[i]))
return false;
return true;
}
static inline bool nfs_silly_rename(char *rpath, const struct fd_parms *parms)
{
return (parms->fs_type == NFS_SUPER_MAGIC) && is_sillyrename_name(rpath);
}
int strip_deleted(struct fd_link *link)
{
struct dcache_prepends {
const char *str;
size_t len;
} static const prepends[] = {
{
.str = " (deleted)",
.len = 10,
}, {
.str = "//deleted",
.len = 9,
}
};
size_t i;
for (i = 0; i < ARRAY_SIZE(prepends); i++) {
size_t at;
if (link->len <= prepends[i].len)
continue;
at = link->len - prepends[i].len;
if (!strcmp(&link->name[at], prepends[i].str)) {
pr_debug("Strip '%s' tag from '%s'\n",
prepends[i].str, link->name);
link->name[at] = '\0';
link->len -= prepends[i].len;
return 1;
}
}
return 0;
}
static int check_path_remap(struct fd_link *link, const struct fd_parms *parms,
int lfd, u32 id, struct ns_id *nsid)
{
char *rpath = link->name;
int plen = link->len;
int ret, mntns_root;
struct stat pst;
const struct stat *ost = &parms->stat;
if (parms->fs_type == PROC_SUPER_MAGIC) {
/* The file points to /proc/pid/<foo> where pid is a dead
* process. We remap this file by adding this pid to be
* fork()ed into a TASK_HELPER state so that we can point to it
* on restore.
*/
pid_t pid;
char *start, *end;
/* skip "./proc/" */
start = strstr(rpath, "/");
if (!start)
return -1;
start = strstr(start + 1, "/");
if (!start) /* it's /proc */
return 0;
pid = strtol(start + 1, &end, 10);
/* If strtol didn't convert anything, then we are looking at
* something like /proc/kmsg, which we shouldn't mess with.
* Anything under /proc/<pid> (including that directory itself)
* can be c/r'd with a dead pid remap, so let's allow all such
* cases.
*/
if (pid != 0) {
bool is_dead = strip_deleted(link);
/* /proc/<pid> will be "/proc/1 (deleted)" when it is
* dead, but a path like /proc/1/mountinfo won't have
* the suffix, since it isn't actually deleted (still
* exists, but the parent dir is deleted). So, if we
* have a path like /proc/1/mountinfo, test if /proc/1
* exists instead, since this is what CRIU will need to
* open on restore.
*/
if (!is_dead) {
*end = 0;
is_dead = access(rpath, F_OK);
*end = '/';
}
if (is_dead) {
pr_info("Dumping dead process remap of %d\n", pid);
return dump_dead_process_remap(pid, id);
}
}
return 0;
} else if (parms->fs_type == DEVPTS_SUPER_MAGIC) {
/*
* It's safe to call stripping here because
* file paths are having predefined format for
* this FS and can't have a valid " (deleted)"
* postfix as a part of not deleted filename.
*/
strip_deleted(link);