[cubemap] / main.cpp

#include <stdio.h>
#include <string.h>
#include <stdint.h>
#include <assert.h>
#include <arpa/inet.h>
#include <sys/socket.h>
#include <pthread.h>
#include <sys/types.h>
#include <sys/ioctl.h>
#include <sys/poll.h>
#include <sys/time.h>
#include <signal.h>
#include <errno.h>
#include <ctype.h>
#include <fcntl.h>
#include <vector>
#include <string>
#include <map>
#include <set>

#include "acceptor.h"
#include "markpool.h"
#include "metacube.h"
#include "parse.h"
#include "server.h"
#include "serverpool.h"
#include "input.h"
#include "stats.h"
#include "state.pb.h"

using namespace std;

ServerPool *servers = NULL;
volatile bool hupped = false;

void hup(int ignored)
{
        hupped = true;
}

// Serialize the given state to a file descriptor, and return the (still open)
// descriptor.
int make_tempfile(const CubemapStateProto &state)
{
        char tmpl[] = "/tmp/cubemapstate.XXXXXX";
        int state_fd = mkstemp(tmpl);
        if (state_fd == -1) {
                perror("mkstemp");
                exit(1);
        }

        string serialized;
        state.SerializeToString(&serialized);

        const char *ptr = serialized.data();
        size_t to_write = serialized.size();
        while (to_write > 0) {
                ssize_t ret = write(state_fd, ptr, to_write);
                if (ret == -1) {
                        perror("write");
                        exit(1);
                }

                ptr += ret;
                to_write -= ret;
        }

        return state_fd;
}

CubemapStateProto collect_state(const timeval &serialize_start,
                                const vector<Acceptor *> acceptors,
                                const vector<Input *> inputs,
                                ServerPool *servers,
                                int num_servers)
{
        CubemapStateProto state;
        state.set_serialize_start_sec(serialize_start.tv_sec);
        state.set_serialize_start_usec(serialize_start.tv_usec);
        
        for (size_t i = 0; i < acceptors.size(); ++i) {
                state.add_acceptors()->MergeFrom(acceptors[i]->serialize());
        }

        for (size_t i = 0; i < inputs.size(); ++i) {
                state.add_inputs()->MergeFrom(inputs[i]->serialize());
        }

        for (int i = 0; i < num_servers; ++i) { 
                CubemapStateProto local_state = servers->get_server(i)->serialize();

                // The stream state should be identical between the servers, so we only store it once.
                if (i == 0) {
                        state.mutable_streams()->MergeFrom(local_state.streams());
                }
                for (int j = 0; j < local_state.clients_size(); ++j) {
                        state.add_clients()->MergeFrom(local_state.clients(j));
                }
        }

        return state;
}

// Read the state back from the file descriptor made by make_tempfile,
// and close it.
CubemapStateProto read_tempfile(int state_fd)
{
        if (lseek(state_fd, 0, SEEK_SET) == -1) {
                perror("lseek");
                exit(1);
        }

        string serialized;
        char buf[4096];
        for ( ;; ) {
                ssize_t ret = read(state_fd, buf, sizeof(buf));
                if (ret == -1) {
                        perror("read");
                        exit(1);
                }
                if (ret == 0) {
                        // EOF.
                        break;
                }

                serialized.append(string(buf, buf + ret));
        }

        close(state_fd);  // Implicitly deletes the file.

        CubemapStateProto state;
        if (!state.ParseFromString(serialized)) {
                fprintf(stderr, "PANIC: Failed deserialization of state.\n");
                exit(1);
        }

        return state;
}
        
// Reuse mark pools if one already exists.
MarkPool *get_mark_pool(map<pair<int, int>, MarkPool *> *mark_pools, int from, int to)
{
        pair<int, int> mark_range(from, to);
        if (mark_pools->count(mark_range) != 0) {
                return (*mark_pools)[mark_range];
        }

        // Check if we're overlapping some other mark pool.
        for (map<pair<int, int>, MarkPool *>::const_iterator mp_it = mark_pools->begin();
             mp_it != mark_pools->end();
             ++mp_it) {
                int other_from = mp_it->first.first;
                int other_to = mp_it->first.second;
                if ((from >= other_from && from < other_to) ||
                    (to >= other_from && to < other_to)) {
                        fprintf(stderr, "WARNING: Mark pool %d-%d partially overlaps with %d-%d, you may get duplicate marks.\n",
                                from, to, other_from, other_to);
                        fprintf(stderr, "         Mark pools must either be completely disjunct, or completely overlapping.\n");
                }
        }       

        MarkPool *mark_pool = new MarkPool(from, to);
        mark_pools->insert(make_pair(mark_range, mark_pool));
        return mark_pool;
}
                        
MarkPool *parse_mark_pool(map<pair<int, int>, MarkPool *> *mark_pools, const string &mark_str)
{
        size_t split = mark_str.find_first_of('-');
        if (split == string::npos) {
                fprintf(stderr, "WARNING: Invalid mark specification '%s' (expected 'X-Y'), ignoring.\n",
                        mark_str.c_str());
                return NULL;
        }

        string from_str(mark_str.begin(), mark_str.begin() + split);
        string to_str(mark_str.begin() + split + 1, mark_str.end());
        int from = atoi(from_str.c_str());
        int to = atoi(to_str.c_str());

        if (from <= 0 || from >= 65536 || to <= 0 || to >= 65536) {
                fprintf(stderr, "WARNING: Mark pool range %d-%d is outside legal range [1,65536>, ignoring.\n",
                        from, to);
                return NULL;
        }

        return get_mark_pool(mark_pools, from, to);
}

// Find all port statements in the configuration file, and create acceptors for htem.
vector<Acceptor *> create_acceptors(
        const vector<ConfigLine> &config,
        map<int, Acceptor *> *deserialized_acceptors)
{
        vector<Acceptor *> acceptors;
        for (unsigned i = 0; i < config.size(); ++i) {
                if (config[i].keyword != "port") {
                        continue;
                }
                if (config[i].arguments.size() != 1) {
                        fprintf(stderr, "ERROR: 'port' takes exactly one argument\n");
                        exit(1);
                }
                int port = atoi(config[i].arguments[0].c_str());
                if (port < 1 || port >= 65536) {
                        fprintf(stderr, "WARNING: port %d is out of range (must be [1,65536>), ignoring\n", port);
                        continue;
                }

                Acceptor *acceptor = NULL;
                map<int, Acceptor *>::iterator deserialized_acceptor_it =
                        deserialized_acceptors->find(port);
                if (deserialized_acceptor_it != deserialized_acceptors->end()) {
                        acceptor = deserialized_acceptor_it->second;
                        deserialized_acceptors->erase(deserialized_acceptor_it);
                } else {
                        int server_sock = create_server_socket(port);
                        acceptor = new Acceptor(server_sock, port);
                }
                acceptor->run();
                acceptors.push_back(acceptor);
        }

        // Close all acceptors that are no longer in the configuration file.
        for (map<int, Acceptor *>::iterator acceptor_it = deserialized_acceptors->begin();
             acceptor_it != deserialized_acceptors->end();
             ++acceptor_it) {
                acceptor_it->second->close_socket();
                delete acceptor_it->second;
        }

        return acceptors;
}

// Find all streams in the configuration file, and create inputs for them.
vector<Input *> create_inputs(const vector<ConfigLine> &config,
                              map<string, Input *> *deserialized_inputs)
{
        vector<Input *> inputs;
        for (unsigned i = 0; i < config.size(); ++i) {
                if (config[i].keyword != "stream") {
                        continue;
                }
                assert(config[i].arguments.size() == 1);
                string stream_id = config[i].arguments[0];

                map<string, string>::const_iterator src_it =
                        config[i].parameters.find("src");
                if (src_it == config[i].parameters.end()) {
                        fprintf(stderr, "WARNING: stream '%s' has no src= attribute, clients will not get any data.\n",
                                stream_id.c_str());
                        continue;
                }

                string src = src_it->second;
                Input *input = NULL;
                map<string, Input *>::iterator deserialized_input_it =
                        deserialized_inputs->find(stream_id);
                if (deserialized_input_it != deserialized_inputs->end()) {
                        input = deserialized_input_it->second;
                        if (input->get_url() != src) {
                                fprintf(stderr, "INFO: Stream '%s' has changed URL from '%s' to '%s', restarting input.\n",
                                        stream_id.c_str(), input->get_url().c_str(), src.c_str());
                                delete input;
                                input = NULL;
                        }
                        deserialized_inputs->erase(deserialized_input_it);
                }
                if (input == NULL) {
                        input = new Input(stream_id, src);
                }
                input->run();
                inputs.push_back(input);
        }
        return inputs;
}

void create_streams(const vector<ConfigLine> &config,
                    const set<string> &deserialized_stream_ids,
                    map<string, Input *> *deserialized_inputs)
{
        set<string> expecting_stream_ids = deserialized_stream_ids;
        map<pair<int, int>, MarkPool *> mark_pools;
        for (unsigned i = 0; i < config.size(); ++i) {
                if (config[i].keyword != "stream") {
                        continue;
                }
                if (config[i].arguments.size() != 1) {
                        fprintf(stderr, "ERROR: 'stream' takes exactly one argument\n");
                        exit(1);
                }
                string stream_id = config[i].arguments[0];
                if (deserialized_stream_ids.count(stream_id) == 0) {
                        servers->add_stream(stream_id);
                }
                expecting_stream_ids.erase(stream_id);

                // Set up marks, if so desired.
                map<string, string>::const_iterator mark_parm_it =
                        config[i].parameters.find("mark");
                if (mark_parm_it != config[i].parameters.end()) {
                        MarkPool *mark_pool = parse_mark_pool(&mark_pools, mark_parm_it->second);
                        servers->set_mark_pool(stream_id, mark_pool);
                }
        }

        // Warn about any servers we've lost.
        // TODO: Make an option (delete=yes?) to actually shut down streams.
        for (set<string>::const_iterator stream_it = expecting_stream_ids.begin();
             stream_it != expecting_stream_ids.end();
             ++stream_it) {
                string stream_id = *stream_it;
                fprintf(stderr, "WARNING: stream '%s' disappeared from the configuration file.\n",
                        stream_id.c_str());
                fprintf(stderr, "         It will not be deleted, but clients will not get any new inputs.\n");
                if (deserialized_inputs->count(stream_id) != 0) {
                        delete (*deserialized_inputs)[stream_id];
                        deserialized_inputs->erase(stream_id);
                }
        }
}

int main(int argc, char **argv)
{
        fprintf(stderr, "\nCubemap starting.\n");

        struct timeval serialize_start;
        bool is_reexec = false;

        string config_filename = (argc == 1) ? "cubemap.config" : argv[1];
        vector<ConfigLine> config = parse_config(config_filename);

        int num_servers = fetch_config_int(config, "num_servers", 1, 20000, PARAMATER_MANDATORY);  // Insanely high max limit.

        servers = new ServerPool(num_servers);

        CubemapStateProto loaded_state;
        set<string> deserialized_stream_ids;
        map<string, Input *> deserialized_inputs;
        map<int, Acceptor *> deserialized_acceptors;
        if (argc == 4 && strcmp(argv[2], "-state") == 0) {
                is_reexec = true;

                fprintf(stderr, "Deserializing state from previous process... ");
                int state_fd = atoi(argv[3]);
                loaded_state = read_tempfile(state_fd);

                serialize_start.tv_sec = loaded_state.serialize_start_sec();
                serialize_start.tv_usec = loaded_state.serialize_start_usec();

                // Deserialize the streams.
                for (int i = 0; i < loaded_state.streams_size(); ++i) {
                        servers->add_stream_from_serialized(loaded_state.streams(i));
                        deserialized_stream_ids.insert(loaded_state.streams(i).stream_id());
                }

                // Deserialize the inputs. Note that we don't actually add them to any state yet.
                for (int i = 0; i < loaded_state.inputs_size(); ++i) {
                        deserialized_inputs.insert(make_pair(
                                loaded_state.inputs(i).stream_id(),
                                new Input(loaded_state.inputs(i))));
                } 

                // Convert the acceptor from older serialized formats.
                if (loaded_state.has_server_sock() && loaded_state.has_port()) {
                        AcceptorProto *acceptor = loaded_state.add_acceptors();
                        acceptor->set_server_sock(loaded_state.server_sock());
                        acceptor->set_port(loaded_state.port());
                }

                // Deserialize the acceptors.
                for (int i = 0; i < loaded_state.acceptors_size(); ++i) {
                        deserialized_acceptors.insert(make_pair(
                                loaded_state.acceptors(i).port(),
                                new Acceptor(loaded_state.acceptors(i))));
                }

                fprintf(stderr, "done.\n");
        }

        // Find all streams in the configuration file, and create them.
        create_streams(config, deserialized_stream_ids, &deserialized_inputs);

        // See if the user wants stats.
        string stats_file = fetch_config_string(config, "stats_file", PARAMETER_OPTIONAL);
        int stats_interval = fetch_config_int(config, "stats_interval", 1, INT_MAX, PARAMETER_OPTIONAL, -1);
        if (stats_interval != -1 && stats_file.empty()) {
                fprintf(stderr, "WARNING: 'stats_interval' given, but no 'stats_file'. No statistics will be written.\n");
        }

        servers->run();

        vector<Acceptor *> acceptors = create_acceptors(config, &deserialized_acceptors);
        vector<Input *> inputs = create_inputs(config, &deserialized_inputs);
        
        // All deserialized inputs should now have been taken care of, one way or the other.
        assert(deserialized_inputs.empty());
        
        if (is_reexec) {        
                // Put back the existing clients. It doesn't matter which server we
                // allocate them to, so just do round-robin. However, we need to add
                // them after the mark pools have been set up.
                for (int i = 0; i < loaded_state.clients_size(); ++i) {
                        servers->add_client_from_serialized(loaded_state.clients(i));
                }
        }

        // Start writing statistics.
        StatsThread *stats_thread = NULL;
        if (!stats_file.empty()) {
                stats_thread = new StatsThread(stats_file, stats_interval);
                stats_thread->run();
        }

        signal(SIGHUP, hup);
        
        struct timeval server_start;
        gettimeofday(&server_start, NULL);
        if (is_reexec) {
                // Measure time from we started deserializing (below) to now, when basically everything
                // is up and running. This is, in other words, a conservative estimate of how long our
                // “glitch” period was, not counting of course reconnects if the configuration changed.
                double glitch_time = server_start.tv_sec - serialize_start.tv_sec +
                        1e-6 * (server_start.tv_usec - serialize_start.tv_usec);
                fprintf(stderr, "Re-exec happened in approx. %.0f ms.\n", glitch_time * 1000.0);
        }

        while (!hupped) {
                usleep(100000);
        }

        // OK, we've been HUPed. Time to shut down everything, serialize, and re-exec.
        gettimeofday(&serialize_start, NULL);

        if (stats_thread != NULL) {
                stats_thread->stop();
        }
        for (size_t i = 0; i < acceptors.size(); ++i) {
                acceptors[i]->stop();
        }
        for (size_t i = 0; i < inputs.size(); ++i) {
                inputs[i]->stop();
        }
        servers->stop();

        fprintf(stderr, "Serializing state and re-execing...\n");
        int state_fd = make_tempfile(collect_state(
                serialize_start, acceptors, inputs, servers, num_servers));
        delete servers;
         
        char buf[16];
        sprintf(buf, "%d", state_fd);

        for ( ;; ) {
                execlp(argv[0], argv[0], config_filename.c_str(), "-state", buf, NULL);
                perror("execlp");
                fprintf(stderr, "PANIC: re-exec of %s failed. Waiting 0.2 seconds and trying again...\n", argv[0]);
                usleep(200000);
        }
}