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sk-unix: make criu respect existing files while restoring ghost unix socket fd

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If there are any file in place of ghost unix socket, criu will delete it at
restore while trying to recreate ghost one.

Reviewed-by: Alexander Mikhalitsyn <alexander.mikhalitsyn@virtuozzo.com>
Reviewed-by: Pavel Tikhomirov <ptikhomirov@virtuozzo.com>
Signed-off-by: Andrey Zhadchenko <andrey.zhadchenko@virtuozzo.com>
This commit is contained in:
Andrey Zhadchenko
2021-01-11 18:17:40 +03:00
committed by Andrei Vagin
parent 49889baa20
commit d0308e5ecc
1 changed files with 43 additions and 41 deletions
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84
criu/sk-unix.c
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@@ -1470,56 +1470,49 @@ static int bind_on_deleted(int sk, struct unix_sk_info *ui)
addr.sun_family = AF_UNIX;
memcpy(&addr.sun_path, ui->name, ui->ue->name.len);
ret = access(ui->name, F_OK);
if (!ret) {
snprintf(path_parked, sizeof(path_parked), UNIX_GHOST_FMT, ui->name);
/*
* In case if there exist any file with same name
* just move it aside for a while, we will move it back
* once ghost socket is processed.
*/
if (unlinkat(AT_FDCWD, path_parked, 0) == 0)
pr_debug("ghost: Unlinked stale socket id %#x ino %d name %s\n",
ui->ue->id, ui->ue->ino, path_parked);
if (rename(ui->name, path_parked)) {
ret = -errno;
pr_perror("ghost: Can't rename id %#x ino %u addr %s -> %s",
ui->ue->id, ui->ue->ino, ui->name, path_parked);
return ret;
}
pr_debug("ghost: id %#x ino %d renamed %s -> %s\n",
ui->ue->id, ui->ue->ino, ui->name, path_parked);
renamed = true;
}
ret = bind(sk, (struct sockaddr *)&addr,
sizeof(addr.sun_family) + ui->ue->name.len);
if (ret < 0) {
/*
* In case if there some real living socket
* with same name just move it aside for a
* while, we will move it back once ghost
* socket is processed.
*/
if (errno == EADDRINUSE) {
snprintf(path_parked, sizeof(path_parked), UNIX_GHOST_FMT, ui->name);
/*
* Say previous restore get killed in a middle due to
* any reason, be ready the file might already exist,
* clean it up.
*/
if (unlinkat(AT_FDCWD, path_parked, 0) == 0)
pr_debug("ghost: Unlinked stale socket id %#x ino %u name %s\n",
ui->ue->id, ui->ue->ino, path_parked);
if (rename(ui->name, path_parked)) {
ret = -errno;
pr_perror("ghost: Can't rename id %#x ino %u addr %s -> %s",
ui->ue->id, ui->ue->ino, ui->name, path_parked);
return ret;
}
pr_debug("ghost: id %#x ino %u renamed %s -> %s\n",
ui->ue->id, ui->ue->ino, ui->name, path_parked);
renamed = true;
ret = bind(sk, (struct sockaddr *)&addr,
sizeof(addr.sun_family) + ui->ue->name.len);
}
if (ret < 0) {
ret = -errno;
pr_perror("ghost: Can't bind on socket id %#x ino %u addr %s",
ui->ue->id, ui->ue->ino, ui->name);
return ret;
}
ret = -errno;
pr_perror("ghost: Can't bind on socket id %#x ino %d addr %s",
ui->ue->id, ui->ue->ino, ui->name);
goto out_rename;
}
ret = restore_file_perms(ui);
if (ret < 0)
return ret;
goto out;
ret = keep_deleted(ui);
if (ret < 0) {
pr_err("ghost: Can't save socket %#x ino %u addr %s into fdstore\n",
ui->ue->id, ui->ue->ino, ui->name);
return -EIO;
ret = -EIO;
}
out:
/*
* Once everything is ready, just remove the socket from the
* filesystem and rename back the original one if it were here.
@@ -1529,19 +1522,18 @@ static int bind_on_deleted(int sk, struct unix_sk_info *ui)
ret = -errno;
pr_perror("ghost: Can't unlink socket %#x ino %u addr %s",
ui->ue->id, ui->ue->ino, ui->name);
return ret;
}
out_rename:
if (renamed) {
if (rename(path_parked, ui->name)) {
ret = -errno;
pr_perror("ghost: Can't rename id %#x ino %u addr %s -> %s",
ui->ue->id, ui->ue->ino, path_parked, ui->name);
return ret;
} else {
pr_debug("ghost: id %#x ino %d renamed %s -> %s\n",
ui->ue->id, ui->ue->ino, path_parked, ui->name);
}
pr_debug("ghost: id %#x ino %u renamed %s -> %s\n",
ui->ue->id, ui->ue->ino, path_parked, ui->name);
}
/*
@@ -1988,6 +1980,7 @@ static struct file_desc_ops unix_desc_ops = {
static int unlink_sk(struct unix_sk_info *ui)
{
int ret = 0, cwd_fd = -1, root_fd = -1, ns_fd = -1;
struct stat statbuf;
if (!ui->name || ui->name[0] == '\0' || (ui->ue->uflags & USK_EXTERN))
return 0;
@@ -1995,6 +1988,15 @@ static int unlink_sk(struct unix_sk_info *ui)
if (prep_unix_sk_cwd(ui, &cwd_fd, &root_fd, NULL))
return -1;
ret = stat(ui->name, &statbuf);
if (!ret) {
/* Do not cleanup non-socket files */
if (!S_ISSOCK(statbuf.st_mode)) {
ret = 0;
goto out;
}
}
ret = unlinkat(AT_FDCWD, ui->name, 0) ? -1 : 0;
if (ret < 0 && errno != ENOENT) {
pr_warn("Can't unlink socket %u peer %u (name %s dir %s)\n",