Function restartServer

app/redis-6.2.6/src/server.c:2797–2844

Restart the server, executing the same executable that started this * instance, with the same arguments and configuration file. * * The function is designed to directly call execve() so that the new * server instance will retain the PID of the previous one. * * The list of flags, that may be bitwise ORed together, alter the * behavior of this function: * * RESTART_SERVER_NONE

 * On success the function does not return, because the process turns into
 * a different process. On error C_ERR is returned. */
int restartServer(int flags, mstime_t delay) {
    int j;

    /* Check if we still have accesses to the executable that started this
     * server instance. */
    if (access(server.executable,X_OK) == -1) {
        serverLog(LL_WARNING,"Can't restart: this process has no "
                             "permissions to execute %s", server.executable);
        return C_ERR;
    }

    /* Config rewriting. */
    if (flags & RESTART_SERVER_CONFIG_REWRITE &&
        server.configfile &&
        rewriteConfig(server.configfile, 0) == -1)
    {
        serverLog(LL_WARNING,"Can't restart: configuration rewrite process "
                             "failed");
        return C_ERR;
    }

    /* Perform a proper shutdown. */
    if (flags & RESTART_SERVER_GRACEFULLY &&
        prepareForShutdown(SHUTDOWN_NOFLAGS) != C_OK)
    {
        serverLog(LL_WARNING,"Can't restart: error preparing for shutdown");
        return C_ERR;
    }

    /* Close all file descriptors, with the exception of stdin, stdout, strerr
     * which are useful if we restart a Redis server which is not daemonized. */
    for (j = 3; j < (int)server.maxclients + 1024; j++) {
        /* Test the descriptor validity before closing it, otherwise
         * Valgrind issues a warning on close(). */
        if (fcntl(j,F_GETFD) != -1) close(j);
    }

    /* Execute the server with the original command line. */
    if (delay) usleep(delay*1000);
    zfree(server.exec_argv[0]);
    server.exec_argv[0] = zstrdup(server.executable);
    execve(server.executable,server.exec_argv,environ);

    /* If an error occurred here, there is nothing we can do, but exit. */
    _exit(1);

    return C_ERR; /* Never reached. */
}

static void readOOMScoreAdj(void) {
#ifdef HAVE_PROC_OOM_SCORE_ADJ