commands: add LXC_CMD_GET_CGROUP_FD

Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>

diff --git a/src/lxc/commands.c b/src/lxc/commands.c
index ef465d70eb9ef86ab54691d09defa0a4141262f8..787565a8b206617672a663bf3f0f9377a9688de1 100644 (file)
--- a/src/lxc/commands.c
+++ b/src/lxc/commands.c
@@ -88,6 +88,7 @@ static const char *lxc_cmd_str(lxc_cmd_t cmd)
                [LXC_CMD_GET_LIMITING_CGROUP2_FD]       = "get_limiting_cgroup2_fd",
                [LXC_CMD_GET_DEVPTS_FD]                 = "get_devpts_fd",
                [LXC_CMD_GET_SECCOMP_NOTIFY_FD]         = "get_seccomp_notify_fd",
+               [LXC_CMD_GET_CGROUP_FD]                 = "get_cgroup_fd",
        };
 
        if (cmd >= LXC_CMD_MAX)
@@ -115,19 +116,34 @@ static const char *lxc_cmd_str(lxc_cmd_t cmd)
  */
 static int lxc_cmd_rsp_recv(int sock, struct lxc_cmd_rr *cmd)
 {
-       call_cleaner(put_unix_fds) struct unix_fds *fds = NULL;
-       int ret;
+       call_cleaner(put_unix_fds) struct unix_fds *fds = &(struct unix_fds){};
        struct lxc_cmd_rsp *rsp = &cmd->rsp;
+       int ret;
 
-       fds = &(struct unix_fds){
-               .fd_count_max = 1,
-       };
-
+       switch (cmd->req.cmd) {
+       case LXC_CMD_GET_CGROUP2_FD:
+               __fallthrough;
+       case LXC_CMD_GET_LIMITING_CGROUP2_FD:
+               __fallthrough;
+       case LXC_CMD_GET_INIT_PIDFD:
+               __fallthrough;
+       case LXC_CMD_GET_SECCOMP_NOTIFY_FD:
+               __fallthrough;
+       case LXC_CMD_GET_DEVPTS_FD:
+               __fallthrough;
+       case LXC_CMD_CONSOLE:
+               fds->fd_count_max = 1;
+               break;
+       case LXC_CMD_GET_CGROUP_FD:
+               fds->fd_count_max = KERNEL_SCM_MAX_FD;
+               break;
+       default:
+               fds->fd_count_max = 0;
+       }
        ret = lxc_abstract_unix_recv_fds(sock, fds, rsp, sizeof(*rsp));
        if (ret < 0)
-               return log_warn_errno(-1,
-                                     errno, "Failed to receive response for command \"%s\"",
-                                     lxc_cmd_str(cmd->req.cmd));
+               return syserrno(ret, "Failed to receive response for command \"%s\"",
+                               lxc_cmd_str(cmd->req.cmd));
        TRACE("Command \"%s\" received response", lxc_cmd_str(cmd->req.cmd));
 
        if (cmd->req.cmd == LXC_CMD_CONSOLE) {
@@ -585,14 +601,20 @@ static int lxc_cmd_get_cgroup_fd_callback(int fd, struct lxc_cmd_req *req,
                                          struct lxc_handler *handler,
                                          struct lxc_epoll_descr *descr)
 {
+       struct lxc_cmd_rsp rsp = {
+               .ret = 0,
+       };
        struct cgroup_ops *cgroup_ops = handler->cgroup_ops;
-       struct lxc_cmd_rsp rsp = {};
-       struct unix_fds fds = {};
+       struct unix_fds *fds = {};
+       int ret;
+
+       fds->fd_count_max = cgroup_fds(cgroup_ops, fds->fd);
+       ret = lxc_abstract_unix_send_fds(fd, fds->fd, fds->fd_count_max,
+                                        &rsp, sizeof(rsp));
+       if (ret < 0)
+               return log_error(ret, "Failed to send cgroup fds");
 
-       fds.fd_count_max = cgroup_fds(cgroup_ops, fds.fd);
-       if (fds.fd_count_max == 0)
-               rsp.ret = -ENOENT;
-       return rsp_many_fds(fd, &fds, &rsp);
+       return log_trace(LXC_CMD_REAP_CLIENT_FD, "Sent cgroup fds");
 }
 
 /*
@@ -1590,6 +1612,7 @@ static int lxc_cmd_process(int fd, struct lxc_cmd_req *req,
                [LXC_CMD_GET_LIMITING_CGROUP2_FD]       = lxc_cmd_get_limiting_cgroup2_fd_callback,
                [LXC_CMD_GET_DEVPTS_FD]                 = lxc_cmd_get_devpts_fd_callback,
                [LXC_CMD_GET_SECCOMP_NOTIFY_FD]         = lxc_cmd_get_seccomp_notify_fd_callback,
+               [LXC_CMD_GET_CGROUP_FD]                 = lxc_cmd_get_cgroup_fd_callback,
        };
 
        if (req->cmd >= LXC_CMD_MAX)

diff --git a/src/lxc/commands.h b/src/lxc/commands.h
index 45c30c1f5ed543adca1dc2bccf97dcd42cfb56a0..2ce5de61f503ef13f88c4f9f5f1b95bf01848622 100644 (file)
--- a/src/lxc/commands.h
+++ b/src/lxc/commands.h
@@ -43,6 +43,7 @@ typedef enum {
        LXC_CMD_GET_LIMITING_CGROUP2_FD         = 20,
        LXC_CMD_GET_DEVPTS_FD                   = 21,
        LXC_CMD_GET_SECCOMP_NOTIFY_FD           = 22,
+       LXC_CMD_GET_CGROUP_FD                   = 23,
        LXC_CMD_MAX,
 } lxc_cmd_t;
 
@@ -122,6 +123,9 @@ __hidden extern int lxc_try_cmd(const char *name, const char *lxcpath);
 __hidden extern int lxc_cmd_console_log(const char *name, const char *lxcpath,
                                        struct lxc_console_log *log);
 __hidden extern int lxc_cmd_get_seccomp_notify_fd(const char *name, const char *lxcpath);
+__hidden extern int lxc_cmd_get_cgroup_fd(const char *name, const char *lxcpath,
+                                         const char *controller, bool batch,
+                                         struct unix_fds *ret_fds);
 __hidden extern int lxc_cmd_seccomp_notify_add_listener(const char *name, const char *lxcpath, int fd,
                                                        /* unused */ unsigned int command,
                                                        /* unused */ unsigned int flags);