/*
* lxc_cmd: Connect to the specified running container, send it a command
* request and collect the response
*
* @name : name of container to connect to
* @cmd : command with initialized request to send
* @stopped : output indicator if the container was not running
* @lxcpath : the lxcpath in which the container is running
*
* Returns the size of the response message on success, < 0 on failure
*
* Note that there is a special case for LXC_CMD_CONSOLE. For this command
* the fd cannot be closed because it is used as a placeholder to indicate
* that a particular tty slot is in use. The fd is also used as a signal to
* the container that when the caller dies or closes the fd, the container
* will notice the fd on its side of the socket in its mainloop select and
* then free the slot with lxc_cmd_fd_cleanup(). The socket fd will be
* returned in the cmd response structure.
*/
static int lxc_cmd(const char *name, struct lxc_cmd_rr *cmd, int *stopped,
const char *lxcpath, const char *hashed_sock_name)
{
__do_close_prot_errno int client_fd = -EBADF;
int ret = -1;
bool stay_connected = false;
if (cmd->req.cmd == LXC_CMD_CONSOLE ||
cmd->req.cmd == LXC_CMD_ADD_STATE_CLIENT)
stay_connected = true;
*stopped = 0;
client_fd = lxc_cmd_send(name, cmd, lxcpath, hashed_sock_name);
if (client_fd < 0) {
SYSTRACE("Command \"%s\" failed to connect command socket",
lxc_cmd_str(cmd->req.cmd));
if (errno == ECONNREFUSED || errno == EPIPE)
*stopped = 1;
return -1;
}
ret = lxc_cmd_rsp_recv(client_fd, cmd);
if (ret < 0 && errno == ECONNRESET)
*stopped = 1;
if (stay_connected && ret > 0)
cmd->rsp.ret = move_fd(client_fd);
return ret;
}
/*
* lxc_cmd: Connect to the specified running container, send it a command
* request and collect the response
*
* @name : name of container to connect to
* @cmd : command with initialized request to send
* @stopped : output indicator if the container was not running
* @lxcpath : the lxcpath in which the container is running
*
* Returns the size of the response message on success, < 0 on failure
*
* Note that there is a special case for LXC_CMD_CONSOLE. For this command
* the fd cannot be closed because it is used as a placeholder to indicate
* that a particular tty slot is in use. The fd is also used as a signal to
* the container that when the caller dies or closes the fd, the container
* will notice the fd on its side of the socket in its mainloop select and
* then free the slot with lxc_cmd_fd_cleanup(). The socket fd will be
* returned in the cmd response structure.
*/
static int lxc_cmd(const char *name, struct lxc_cmd_rr *cmd, int *stopped,
const char *lxcpath, const char *hashed_sock_name)
{
int client_fd, saved_errno;
int ret = -1;
bool stay_connected = false;
if (cmd->req.cmd == LXC_CMD_CONSOLE ||
cmd->req.cmd == LXC_CMD_ADD_STATE_CLIENT)
stay_connected = true;
*stopped = 0;
client_fd = lxc_cmd_send(name, cmd, lxcpath, hashed_sock_name);
if (client_fd < 0) {
SYSTRACE("Command \"%s\" failed to connect command socket",
lxc_cmd_str(cmd->req.cmd));
if (errno == ECONNREFUSED)
*stopped = 1;
if (errno == EPIPE) {
*stopped = 1;
client_fd = 0;
}
return -1;
}
ret = lxc_cmd_rsp_recv(client_fd, cmd);
if (ret < 0 && errno == ECONNRESET)
*stopped = 1;
if (!stay_connected || ret <= 0)
if (client_fd >= 0) {
saved_errno = errno;
close(client_fd);
errno = saved_errno;
}
if (stay_connected && ret > 0)
cmd->rsp.ret = client_fd;
return ret;
}
/*
* lxc_cmd_rsp_recv: Receive a response to a command
*
* @sock : the socket connected to the container
* @cmd : command to put response in
*
* Returns the size of the response message or < 0 on failure
*
* Note that if the command response datalen > 0, then data is
* a malloc()ed buffer and should be free()ed by the caller. If
* the response data is <= a void * worth of data, it will be
* stored directly in data and datalen will be 0.
*
* As a special case, the response for LXC_CMD_CONSOLE is created
* here as it contains an fd for the master pty passed through the
* unix socket.
*/
static int lxc_cmd_rsp_recv(int sock, struct lxc_cmd_rr *cmd)
{
int ret, rspfd;
struct lxc_cmd_rsp *rsp = &cmd->rsp;
ret = lxc_abstract_unix_recv_fds(sock, &rspfd, 1, rsp, sizeof(*rsp));
if (ret < 0) {
SYSWARN("Failed to receive response for command \"%s\"",
lxc_cmd_str(cmd->req.cmd));
if (errno == ECONNRESET)
return -1;
return -1;
}
TRACE("Command \"%s\" received response", lxc_cmd_str(cmd->req.cmd));
if (cmd->req.cmd == LXC_CMD_CONSOLE) {
struct lxc_cmd_console_rsp_data *rspdata;
/* recv() returns 0 bytes when a tty cannot be allocated,
* rsp->ret is < 0 when the peer permission check failed
*/
if (ret == 0 || rsp->ret < 0)
return 0;
rspdata = malloc(sizeof(*rspdata));
if (!rspdata) {
errno = ENOMEM;
ERROR("Failed to allocate response buffer for command \"%s\"",
lxc_cmd_str(cmd->req.cmd));
return -1;
}
rspdata->masterfd = rspfd;
rspdata->ttynum = PTR_TO_INT(rsp->data);
rsp->data = rspdata;
}
if (rsp->datalen == 0) {
DEBUG("Response data length for command \"%s\" is 0",
lxc_cmd_str(cmd->req.cmd));
return ret;
}
if ((rsp->datalen > LXC_CMD_DATA_MAX) &&
(cmd->req.cmd != LXC_CMD_CONSOLE_LOG)) {
ERROR("Response data for command \"%s\" is too long: %d bytes > %d",
lxc_cmd_str(cmd->req.cmd), rsp->datalen, LXC_CMD_DATA_MAX);
return -1;
}
if (cmd->req.cmd == LXC_CMD_CONSOLE_LOG) {
rsp->data = malloc(rsp->datalen + 1);
((char *)rsp->data)[rsp->datalen] = '\0';
} else {
rsp->data = malloc(rsp->datalen);
}
if (!rsp->data) {
errno = ENOMEM;
ERROR("Failed to allocate response buffer for command \"%s\"",
lxc_cmd_str(cmd->req.cmd));
return -1;
}
ret = lxc_recv_nointr(sock, rsp->data, rsp->datalen, 0);
if (ret != rsp->datalen) {
SYSERROR("Failed to receive response data for command \"%s\"",
lxc_cmd_str(cmd->req.cmd));
return -1;
}
return ret;
}
