replication/replicator/notify-connection.c

/* Copyright (c) 2013-2018 Dovecot authors, see the included COPYING file */

#include "lib.h"
#include "llist.h"
#include "istream.h"
#include "ostream.h"
#include "strescape.h"
#include "master-service.h"
#include "replicator-queue.h"
#include "notify-connection.h"

#include <unistd.h>

#define MAX_INBUF_SIZE (1024*64)
#define NOTIFY_CLIENT_PROTOCOL_MAJOR_VERSION 1
#define NOTIFY_CLIENT_PROTOCOL_MINOR_VERSION 0

struct notify_connection {
    struct notify_connection *prev, *next;
    int refcount;

    int fd;
    struct io *io;
    struct istream *input;
    struct ostream *output;

    struct replicator_queue *queue;

    bool version_received:1;
    bool destroyed:1;
};

struct notify_sync_request {
    struct notify_connection *conn;
    unsigned int id;
};

static struct notify_connection *connections;

static void notify_connection_destroy(struct notify_connection *conn);

static void notify_sync_callback(bool success, void *context)
{
    struct notify_sync_request *request = context;

    o_stream_nsend_str(request->conn->output, t_strdup_printf(
        "%c\t%u\n", success ? '+' : '-', request->id));

    notify_connection_unref(&request->conn);
    i_free(request);
}

static int
notify_connection_input_line(struct notify_connection *conn, const char *line)
{
    struct notify_sync_request *request;
    const char *const *args;
    enum replication_priority priority;
    unsigned int id;

    /* U \t <username> \t <priority> [\t <sync id>] */
    args = t_strsplit_tabescaped(line);
    if (str_array_length(args) < 2) {
        i_error("notify client sent invalid input: %s", line);
        return -1;
    }
    if (strcmp(args[0], "U") != 0) {
        i_error("notify client sent unknown command: %s", args[0]);
        return -1;
    }
    if (replication_priority_parse(args[2], &priority) < 0) {
        i_error("notify client sent invalid priority: %s", args[2]);
        return -1;
    }
    if (priority != REPLICATION_PRIORITY_SYNC)
        (void)replicator_queue_add(conn->queue, args[1], priority);
    else if (args[3] == NULL || str_to_uint(args[3], &id) < 0) {
        i_error("notify client sent invalid sync id: %s", line);
        return -1;
    } else {
        request = i_new(struct notify_sync_request, 1);
        request->conn = conn;
        request->id = id;
        notify_connection_ref(conn);
        replicator_queue_add_sync(conn->queue, args[1],
                      notify_sync_callback, request);
    }
    return 0;
}

static void notify_connection_input(struct notify_connection *conn)
{
    const char *line;
    int ret;

    switch (i_stream_read(conn->input)) {
    case -2:
        i_error("BUG: Client connection sent too much data");
        notify_connection_destroy(conn);
        return;
    case -1:
        notify_connection_destroy(conn);
        return;
    }

    if (!conn->version_received) {
        if ((line = i_stream_next_line(conn->input)) == NULL)
            return;

        if (!version_string_verify(line, "replicator-notify",
                NOTIFY_CLIENT_PROTOCOL_MAJOR_VERSION)) {
            i_error("Notify client not compatible with this server "
                "(mixed old and new binaries?)");
            notify_connection_destroy(conn);
            return;
        }
        conn->version_received = TRUE;
    }

    while ((line = i_stream_next_line(conn->input)) != NULL) {
        T_BEGIN {
            ret = notify_connection_input_line(conn, line);
        } T_END;
        if (ret < 0) {
            notify_connection_destroy(conn);
            break;
        }
    }
}

struct notify_connection *
notify_connection_create(int fd, struct replicator_queue *queue)
{
    struct notify_connection *conn;

    i_assert(fd >= 0);

    conn = i_new(struct notify_connection, 1);
    conn->refcount = 1;
    conn->queue = queue;
    conn->fd = fd;
    conn->input = i_stream_create_fd(fd, MAX_INBUF_SIZE);
    conn->output = o_stream_create_fd(fd, (size_t)-1);
    o_stream_set_no_error_handling(conn->output, TRUE);
    conn->io = io_add(fd, IO_READ, notify_connection_input, conn);
    conn->queue = queue;

    DLLIST_PREPEND(&connections, conn);
    return conn;
}

static void notify_connection_destroy(struct notify_connection *conn)
{
    if (conn->destroyed)
        return;
    conn->destroyed = TRUE;

    DLLIST_REMOVE(&connections, conn);

    io_remove(&conn->io);
    i_stream_close(conn->input);
    o_stream_close(conn->output);
    if (close(conn->fd) < 0)
        i_error("close(notify connection) failed: %m");
    conn->fd = -1;

    notify_connection_unref(&conn);
    master_service_client_connection_destroyed(master_service);
}

void notify_connection_ref(struct notify_connection *conn)
{
    i_assert(conn->refcount > 0);

    conn->refcount++;
}

void notify_connection_unref(struct notify_connection **_conn)
{
    struct notify_connection *conn = *_conn;

    i_assert(conn->refcount > 0);

    *_conn = NULL;
    if (--conn->refcount > 0)
        return;

    notify_connection_destroy(conn);
    i_stream_unref(&conn->input);
    o_stream_unref(&conn->output);
    i_free(conn);
}

void notify_connections_destroy_all(void)
{
    while (connections != NULL)
        notify_connection_destroy(connections);
}