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Code Issues Releases Wiki Activity

conf: move file descriptor synchronization with child into single function

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Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
This commit is contained in:
Christian Brauner
2021-05-21 10:06:27 +02:00
parent 98db769c83
commit 493ae3fe7e
3 changed files with 69 additions and 63 deletions
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67
src/lxc/conf.c
View File

@@ -1635,7 +1635,7 @@ static const struct id_map *find_mapped_nsid_entry(const struct lxc_conf *conf,
return retmap;
}
int lxc_setup_devpts_parent(struct lxc_handler *handler)
static int lxc_setup_devpts_parent(struct lxc_handler *handler)
{
int ret;
@@ -4013,6 +4013,71 @@ int lxc_idmapped_mounts_parent(struct lxc_handler *handler)
}
}
static int lxc_recv_ttys_from_child(struct lxc_handler *handler)
{
int i;
struct lxc_terminal_info *tty;
int ret = -1;
int sock = handler->data_sock[1];
struct lxc_conf *conf = handler->conf;
struct lxc_tty_info *ttys = &conf->ttys;
if (!conf->ttys.max)
return 0;
ttys->tty = malloc(sizeof(*ttys->tty) * ttys->max);
if (!ttys->tty)
return -1;
for (i = 0; i < conf->ttys.max; i++) {
int ttyx = -EBADF, ttyy = -EBADF;
ret = lxc_abstract_unix_recv_two_fds(sock, &ttyx, &ttyy);
if (ret < 0)
break;
tty = &ttys->tty[i];
tty->busy = -1;
tty->ptx = ttyx;
tty->pty = ttyy;
TRACE("Received pty with ptx fd %d and pty fd %d from child", tty->ptx, tty->pty);
}
if (ret < 0)
SYSERROR("Failed to receive %zu ttys from child", ttys->max);
else
TRACE("Received %zu ttys from child", ttys->max);
return ret;
}
int lxc_sync_fds_parent(struct lxc_handler *handler)
{
int ret;
ret = lxc_seccomp_recv_notifier_fd(&handler->conf->seccomp, handler->data_sock[1]);
if (ret < 0)
return syserror_ret(ret, "Failed to receive seccomp notify fd from child");
ret = lxc_setup_devpts_parent(handler);
if (ret < 0)
return syserror_ret(ret, "Failed to receive devpts fd from child");
/* Read tty fds allocated by child. */
ret = lxc_recv_ttys_from_child(handler);
if (ret < 0)
return syserror_ret(ret, "Failed to receive tty info from child process");
if (handler->ns_clone_flags & CLONE_NEWNET) {
ret = lxc_network_recv_name_and_ifindex_from_child(handler);
if (ret < 0)
return syserror_ret(ret, "Failed to receive names and ifindices for network devices from child");
}
TRACE("Finished syncing file descriptors with child");
return 0;
}
int lxc_setup(struct lxc_handler *handler)
{
int ret;

2
src/lxc/conf.h
View File

@@ -582,7 +582,7 @@ static inline int chown_mapped_root(const char *path, const struct lxc_conf *con
return userns_exec_mapped_root(path, -EBADF, conf);
}
__hidden int lxc_setup_devpts_parent(struct lxc_handler *handler);
__hidden extern int lxc_sync_fds_parent(struct lxc_handler *handler);
static inline const char *get_rootfs_mnt(const struct lxc_rootfs *rootfs)
{

63
src/lxc/start.c
View File

@@ -1464,44 +1464,6 @@ out_error:
return -1;
}
static int lxc_recv_ttys_from_child(struct lxc_handler *handler)
{
int i;
struct lxc_terminal_info *tty;
int ret = -1;
int sock = handler->data_sock[1];
struct lxc_conf *conf = handler->conf;
struct lxc_tty_info *ttys = &conf->ttys;
if (!conf->ttys.max)
return 0;
ttys->tty = malloc(sizeof(*ttys->tty) * ttys->max);
if (!ttys->tty)
return -1;
for (i = 0; i < conf->ttys.max; i++) {
int ttyx = -EBADF, ttyy = -EBADF;
ret = lxc_abstract_unix_recv_two_fds(sock, &ttyx, &ttyy);
if (ret < 0)
break;
tty = &ttys->tty[i];
tty->busy = -1;
tty->ptx = ttyx;
tty->pty = ttyy;
TRACE("Received pty with ptx fd %d and pty fd %d from child", tty->ptx, tty->pty);
}
if (ret < 0)
SYSERROR("Failed to receive %zu ttys from child", ttys->max);
else
TRACE("Received %zu ttys from child", ttys->max);
return ret;
}
int resolve_clone_flags(struct lxc_handler *handler)
{
int i;
@@ -1959,33 +1921,12 @@ static int lxc_spawn(struct lxc_handler *handler)
if (!lxc_sync_wake_child(handler, START_SYNC_FDS))
goto out_delete_net;
ret = lxc_seccomp_recv_notifier_fd(&handler->conf->seccomp, data_sock1);
ret = lxc_sync_fds_parent(handler);
if (ret < 0) {
SYSERROR("Failed to receive seccomp notify fd from child");
SYSERROR("Failed to sync file descriptors with child");
goto out_delete_net;
}
ret = lxc_setup_devpts_parent(handler);
if (ret < 0) {
SYSERROR("Failed to receive devpts fd from child");
goto out_delete_net;
}
/* Read tty fds allocated by child. */
ret = lxc_recv_ttys_from_child(handler);
if (ret < 0) {
ERROR("Failed to receive tty info from child process");
goto out_delete_net;
}
if (handler->ns_clone_flags & CLONE_NEWNET) {
ret = lxc_network_recv_name_and_ifindex_from_child(handler);
if (ret < 0) {
ERROR("Failed to receive names and ifindices for network devices from child");
goto out_delete_net;
}
}
/*
* Tell the child to complete its initialization and wait for it to
* exec or return an error. (The child will never return