From a12081aa986c4cc878bf0480a5d0ffb986aed0c5 Mon Sep 17 00:00:00 2001 From: Felix Fietkau Date: Sat, 21 Jan 2012 20:25:15 +0100 Subject: [PATCH] proto-shell: rework task statemachine Make handling setup/proto/teardown tasks more explicit and easier to read. Should hopefully prevent some forms of deadlocks. --- proto-shell.c | 124 ++++++++++++++++++++++++++++++++++---------------- 1 file changed, 85 insertions(+), 39 deletions(-) diff --git a/proto-shell.c b/proto-shell.c index 51a6dac..5e89288 100644 --- a/proto-shell.c +++ b/proto-shell.c @@ -20,6 +20,13 @@ static struct netifd_fd proto_fd; +enum proto_shell_sm { + S_IDLE, + S_SETUP, + S_SETUP_ABORT, + S_TEARDOWN, +}; + struct proto_shell_handler { struct list_head list; struct proto_handler proto; @@ -36,13 +43,15 @@ struct proto_shell_state { struct device_user l3_dev; - struct uloop_timeout setup_timeout; + struct uloop_timeout teardown_timeout; + struct netifd_process setup_task; struct netifd_process teardown_task; - bool teardown_pending; - bool teardown_wait_task; - struct netifd_process proto_task; + + enum proto_shell_sm sm; + bool proto_task_killed; + int last_error; }; @@ -68,18 +77,28 @@ proto_shell_handler(struct interface_proto_state *proto, proc = &state->setup_task; state->last_error = -1; } else { - action = "teardown"; - proc = &state->teardown_task; - if (state->setup_task.uloop.pending && !state->teardown_wait_task) { - uloop_timeout_set(&state->setup_timeout, 1000); - kill(state->setup_task.uloop.pid, SIGTERM); - state->teardown_pending = true; + if (state->sm == S_TEARDOWN) + return 0; + + if (state->setup_task.uloop.pending) { + if (state->sm != S_SETUP_ABORT) { + uloop_timeout_set(&state->teardown_timeout, 1000); + kill(state->setup_task.uloop.pid, SIGTERM); + if (state->proto_task.uloop.pending) + kill(state->proto_task.uloop.pid, SIGTERM); + state->sm = S_SETUP_ABORT; + } return 0; } + + action = "teardown"; + proc = &state->teardown_task; + state->sm = S_TEARDOWN; if (state->last_error >= 0) { snprintf(error_buf, sizeof(error_buf), "ERROR=%d", state->last_error); envp[j++] = error_buf; } + uloop_timeout_set(&state->teardown_timeout, 5000); } config = blobmsg_format_json(state->config, true); @@ -103,12 +122,58 @@ proto_shell_handler(struct interface_proto_state *proto, } static void -proto_shell_setup_timeout_cb(struct uloop_timeout *timeout) +proto_shell_task_finish(struct proto_shell_state *state, + struct netifd_process *task) +{ + switch (state->sm) { + case S_IDLE: + if (task == &state->proto_task) + state->proto.proto_event(&state->proto, IFPEV_LINK_LOST); + /* fall through */ + case S_SETUP: + if (task == &state->proto_task) + proto_shell_handler(&state->proto, PROTO_CMD_TEARDOWN, + false); + break; + + case S_SETUP_ABORT: + if (state->setup_task.uloop.pending || + state->proto_task.uloop.pending) + break; + + uloop_timeout_cancel(&state->teardown_timeout); + state->sm = S_IDLE; + proto_shell_handler(&state->proto, PROTO_CMD_TEARDOWN, false); + break; + + case S_TEARDOWN: + if (state->teardown_task.uloop.pending) + break; + + if (state->proto_task.uloop.pending) { + if (!state->proto_task_killed) + kill(state->proto_task.uloop.pid, SIGTERM); + break; + } + + uloop_timeout_cancel(&state->teardown_timeout); + state->sm = S_IDLE; + state->proto.proto_event(&state->proto, IFPEV_DOWN); + break; + } +} + +static void +proto_shell_teardown_timeout_cb(struct uloop_timeout *timeout) { struct proto_shell_state *state; - state = container_of(timeout, struct proto_shell_state, setup_timeout); - kill(state->setup_task.uloop.pid, SIGKILL); + state = container_of(timeout, struct proto_shell_state, teardown_timeout); + + netifd_kill_process(&state->setup_task); + netifd_kill_process(&state->proto_task); + netifd_kill_process(&state->teardown_task); + proto_shell_task_finish(state, NULL); } static void @@ -117,11 +182,7 @@ proto_shell_setup_cb(struct netifd_process *p, int ret) struct proto_shell_state *state; state = container_of(p, struct proto_shell_state, setup_task); - uloop_timeout_cancel(&state->setup_timeout); - if (state->teardown_pending) { - state->teardown_pending = false; - proto_shell_handler(&state->proto, PROTO_CMD_TEARDOWN, false); - } + proto_shell_task_finish(state, p); } static void @@ -130,35 +191,20 @@ proto_shell_teardown_cb(struct netifd_process *p, int ret) struct proto_shell_state *state; state = container_of(p, struct proto_shell_state, teardown_task); - - if (state->teardown_wait_task) - return; - - netifd_kill_process(&state->proto_task); - state->proto.proto_event(&state->proto, IFPEV_DOWN); + proto_shell_task_finish(state, p); } static void proto_shell_task_cb(struct netifd_process *p, int ret) { struct proto_shell_state *state; - bool teardown_wait_task; state = container_of(p, struct proto_shell_state, proto_task); - teardown_wait_task = state->teardown_wait_task; - state->teardown_wait_task = false; - if (state->teardown_pending || state->teardown_task.uloop.pending) - return; - - if (teardown_wait_task) { - proto_shell_teardown_cb(&state->teardown_task, 0); - return; - } + if (state->sm == S_IDLE || state->sm == S_SETUP) + state->last_error = WEXITSTATUS(ret); - state->last_error = WEXITSTATUS(ret); - state->proto.proto_event(&state->proto, IFPEV_LINK_LOST); - proto_shell_handler(&state->proto, PROTO_CMD_TEARDOWN, false); + proto_shell_task_finish(state, p); } static void @@ -379,8 +425,8 @@ proto_shell_kill_command(struct proto_shell_state *state, struct blob_attr **tb) signal = SIGTERM; if (state->proto_task.uloop.pending) { + state->proto_task_killed = true; kill(state->proto_task.uloop.pid, signal); - state->teardown_wait_task = true; } return 0; @@ -484,7 +530,7 @@ proto_shell_attach(const struct proto_handler *h, struct interface *iface, state->proto.free = proto_shell_free; state->proto.notify = proto_shell_notify; state->proto.cb = proto_shell_handler; - state->setup_timeout.cb = proto_shell_setup_timeout_cb; + state->teardown_timeout.cb = proto_shell_teardown_timeout_cb; state->setup_task.cb = proto_shell_setup_cb; state->setup_task.dir_fd = proto_fd.fd; state->setup_task.log_prefix = iface->name; -- 2.25.1