[lxc-devel] [PATCH v3 1/6] lxc-start: Add command to retrieve the clone flags used to start the container.
Serge Hallyn
serge.hallyn at canonical.com
Thu May 24 14:10:45 UTC 2012
Quoting Christian Seiler (christian at iwakd.de):
> Add the LXC_COMMAND_CLONE_FLAGS that retrieves the flags passed to clone(2)
> when the container was started. This allows external programs to determine
> which namespaces the container was unshared from.
>
> Signed-off-by: Christian Seiler <christian at iwakd.de>
> Cc: Daniel Lezcano <daniel.lezcano at free.fr>
> Cc: Serge Hallyn <serge.hallyn at canonical.com>
Acked-by: Serge Hallyn <serge.hallyn at canonical.com>
> ---
> src/lxc/commands.c | 30 ++++++++++++++++++++++++++----
> src/lxc/commands.h | 2 ++
> src/lxc/start.c | 34 ++++++++++++++++++++++++++++------
> src/lxc/start.h | 1 +
> 4 files changed, 57 insertions(+), 10 deletions(-)
>
> diff --git a/src/lxc/commands.c b/src/lxc/commands.c
> index 1d488ae..3e551ee 100644
> --- a/src/lxc/commands.c
> +++ b/src/lxc/commands.c
> @@ -148,11 +148,32 @@ pid_t get_init_pid(const char *name)
> return command.answer.pid;
> }
>
> +int lxc_get_clone_flags(const char *name)
> +{
> + struct lxc_command command = {
> + .request = { .type = LXC_COMMAND_CLONE_FLAGS },
> + };
> +
> + int ret, stopped = 0;
> +
> + ret = lxc_command(name, &command, &stopped);
> + if (ret < 0 && stopped)
> + return -1;
> +
> + if (ret < 0) {
> + ERROR("failed to send command");
> + return -1;
> + }
> +
> + return command.answer.ret;
> +}
> +
> extern void lxc_console_remove_fd(int, struct lxc_tty_info *);
> extern int lxc_console_callback(int, struct lxc_request *, struct lxc_handler *);
> extern int lxc_stop_callback(int, struct lxc_request *, struct lxc_handler *);
> extern int lxc_state_callback(int, struct lxc_request *, struct lxc_handler *);
> extern int lxc_pid_callback(int, struct lxc_request *, struct lxc_handler *);
> +extern int lxc_clone_flags_callback(int, struct lxc_request *, struct lxc_handler *);
>
> static int trigger_command(int fd, struct lxc_request *request,
> struct lxc_handler *handler)
> @@ -160,10 +181,11 @@ static int trigger_command(int fd, struct lxc_request *request,
> typedef int (*callback)(int, struct lxc_request *, struct lxc_handler *);
>
> callback cb[LXC_COMMAND_MAX] = {
> - [LXC_COMMAND_TTY] = lxc_console_callback,
> - [LXC_COMMAND_STOP] = lxc_stop_callback,
> - [LXC_COMMAND_STATE] = lxc_state_callback,
> - [LXC_COMMAND_PID] = lxc_pid_callback,
> + [LXC_COMMAND_TTY] = lxc_console_callback,
> + [LXC_COMMAND_STOP] = lxc_stop_callback,
> + [LXC_COMMAND_STATE] = lxc_state_callback,
> + [LXC_COMMAND_PID] = lxc_pid_callback,
> + [LXC_COMMAND_CLONE_FLAGS] = lxc_clone_flags_callback,
> };
>
> if (request->type < 0 || request->type >= LXC_COMMAND_MAX)
> diff --git a/src/lxc/commands.h b/src/lxc/commands.h
> index d5c013f..3b0ac9a 100644
> --- a/src/lxc/commands.h
> +++ b/src/lxc/commands.h
> @@ -28,6 +28,7 @@ enum {
> LXC_COMMAND_STOP,
> LXC_COMMAND_STATE,
> LXC_COMMAND_PID,
> + LXC_COMMAND_CLONE_FLAGS,
> LXC_COMMAND_MAX,
> };
>
> @@ -48,6 +49,7 @@ struct lxc_command {
> };
>
> extern pid_t get_init_pid(const char *name);
> +extern int lxc_get_clone_flags(const char *name);
>
> extern int lxc_command(const char *name, struct lxc_command *command,
> int *stopped);
> diff --git a/src/lxc/start.c b/src/lxc/start.c
> index 920ff77..7e9913f 100644
> --- a/src/lxc/start.c
> +++ b/src/lxc/start.c
> @@ -277,6 +277,29 @@ int lxc_pid_callback(int fd, struct lxc_request *request,
> return 0;
> }
>
> +int lxc_clone_flags_callback(int fd, struct lxc_request *request,
> + struct lxc_handler *handler)
> +{
> + struct lxc_answer answer;
> + int ret;
> +
> + answer.pid = 0;
> + answer.ret = handler->clone_flags;
> +
> + ret = send(fd, &answer, sizeof(answer), 0);
> + if (ret < 0) {
> + WARN("failed to send answer to the peer");
> + return -1;
> + }
> +
> + if (ret != sizeof(answer)) {
> + ERROR("partial answer sent");
> + return -1;
> + }
> +
> + return 0;
> +}
> +
> int lxc_set_state(const char *name, struct lxc_handler *handler, lxc_state_t state)
> {
> handler->state = state;
> @@ -531,17 +554,16 @@ out_warn_father:
>
> int lxc_spawn(struct lxc_handler *handler)
> {
> - int clone_flags;
> int failed_before_rename = 0;
> const char *name = handler->name;
>
> if (lxc_sync_init(handler))
> return -1;
>
> - clone_flags = CLONE_NEWUTS|CLONE_NEWPID|CLONE_NEWIPC|CLONE_NEWNS;
> + handler->clone_flags = CLONE_NEWUTS|CLONE_NEWPID|CLONE_NEWIPC|CLONE_NEWNS;
> if (!lxc_list_empty(&handler->conf->network)) {
>
> - clone_flags |= CLONE_NEWNET;
> + handler->clone_flags |= CLONE_NEWNET;
>
> /* Find gateway addresses from the link device, which is
> * no longer accessible inside the container. Do this
> @@ -564,7 +586,7 @@ int lxc_spawn(struct lxc_handler *handler)
> }
>
> /* Create a process in a new set of namespaces */
> - handler->pid = lxc_clone(do_start, handler, clone_flags);
> + handler->pid = lxc_clone(do_start, handler, handler->clone_flags);
> if (handler->pid < 0) {
> SYSERROR("failed to fork into a new namespace");
> goto out_delete_net;
> @@ -582,7 +604,7 @@ int lxc_spawn(struct lxc_handler *handler)
> goto out_delete_net;
>
> /* Create the network configuration */
> - if (clone_flags & CLONE_NEWNET) {
> + if (handler->clone_flags & CLONE_NEWNET) {
> if (lxc_assign_network(&handler->conf->network, handler->pid)) {
> ERROR("failed to create the configured network");
> goto out_delete_net;
> @@ -608,7 +630,7 @@ int lxc_spawn(struct lxc_handler *handler)
> return 0;
>
> out_delete_net:
> - if (clone_flags & CLONE_NEWNET)
> + if (handler->clone_flags & CLONE_NEWNET)
> lxc_delete_network(&handler->conf->network);
> out_abort:
> lxc_abort(name, handler);
> diff --git a/src/lxc/start.h b/src/lxc/start.h
> index 016d3ee..74f8bf0 100644
> --- a/src/lxc/start.h
> +++ b/src/lxc/start.h
> @@ -39,6 +39,7 @@ struct lxc_handler {
> pid_t pid;
> char *name;
> lxc_state_t state;
> + int clone_flags;
> int sigfd;
> sigset_t oldmask;
> struct lxc_conf *conf;
> --
> 1.7.2.5
>
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