perchild.c

Apache V2.0.15 Alpha For Linuxhttpd-2_0_15-alpha.tar.Z

        ap_log_error(APLOG_MARK, APLOG_ERR, rv, NULL, "apr_os_sock_get");
    }

    if (csd >= FD_SETSIZE) {
        ap_log_error(APLOG_MARK, APLOG_NOERRNO|APLOG_WARNING, 0, NULL,
                     "new file descriptor %d is too large; you probably need "
                     "to rebuild Apache with a larger FD_SETSIZE "
                     "(currently %d)", 
                     csd, FD_SETSIZE);
        apr_socket_close(sock);
        return;
    }

    if (thread_socket_table[thread_num] < 0) {
        ap_sock_disable_nagle(sock);
    }

    current_conn = ap_new_connection(p, ap_server_conf, sock, conn_id);
    if (current_conn) {
        ap_process_connection(current_conn);
        ap_lingering_close(current_conn);
    }
}

static void *worker_thread(void *);

/* Starts a thread as long as we're below max_threads */
static int start_thread(void)
{
    apr_thread_t *thread;
    int rc;

    apr_lock_acquire(worker_thread_count_mutex);
    if (worker_thread_count < max_threads - 1) {
        if ((rc = apr_thread_create(&thread, worker_thread_attr, worker_thread,
	               &worker_thread_free_ids[worker_thread_count], pchild))) {
            ap_log_error(APLOG_MARK, APLOG_ALERT, rc, ap_server_conf,
                         "apr_thread_create: unable to create worker thread");
            /* In case system resources are maxxed out, we don't want
               Apache running away with the CPU trying to fork over and
               over and over again if we exit. */
            sleep(10);
            workers_may_exit = 1;
            apr_lock_release(worker_thread_count_mutex);
            return 0;
        }
	else {
	    worker_thread_count++;
	}
    }
    else {
        static int reported = 0;
        
        if (!reported) {
            ap_log_error(APLOG_MARK, APLOG_NOERRNO|APLOG_ERR, 0, ap_server_conf,
                         "server reached MaxThreadsPerChild setting, consider raising the"
                         " MaxThreadsPerChild or NumServers settings");
            reported = 1;
        }
        apr_lock_release(worker_thread_count_mutex);
        return 0;
    }
    apr_lock_release(worker_thread_count_mutex);
    return 1;

}
/* Sets workers_may_exit if we received a character on the pipe_of_death */
static void check_pipe_of_death(void)
{
    apr_lock_acquire(pipe_of_death_mutex);
    if (!workers_may_exit) {
        int ret;
        char pipe_read_char;
        apr_size_t n = 1;

        ret = apr_recv(listenfds[0], &pipe_read_char, &n);
        if (APR_STATUS_IS_EAGAIN(ret)) {
            /* It lost the lottery. It must continue to suffer
             * through a life of servitude. */
        }
        else {
            /* It won the lottery (or something else is very
             * wrong). Embrace death with open arms. */
            workers_may_exit = 1;
        }
    }
    apr_lock_release(pipe_of_death_mutex);
}

/* idle_thread_count should be incremented before starting a worker_thread */

static void *worker_thread(void *arg)
{
    apr_socket_t *csd = NULL;
    apr_pool_t *tpool;		/* Pool for this thread           */
    apr_pool_t *ptrans;		/* Pool for per-transaction stuff */
    apr_socket_t *sd = NULL;
    int srv;
    int curr_pollfd, last_pollfd = 0;
    int thread_just_started = 1;
    int thread_num = *((int *) arg);
    long conn_id = child_num * HARD_THREAD_LIMIT + thread_num;
    apr_pollfd_t *pollset;
    int n;
    apr_status_t rv;

    apr_lock_acquire(thread_pool_parent_mutex);
    apr_pool_create(&tpool, thread_pool_parent);
    apr_lock_release(thread_pool_parent_mutex);
    apr_pool_create(&ptrans, tpool);

    (void) ap_update_child_status(child_num, thread_num, SERVER_STARTING,
                                  (request_rec *) NULL);

    apr_poll_setup(&pollset, num_listenfds+1, tpool);
    for(n=0 ; n <= num_listenfds ; ++n) {
        apr_poll_socket_add(pollset, listenfds[n], APR_POLLIN);
    }

    while (!workers_may_exit) {
        workers_may_exit |= (max_requests_per_child != 0) && (requests_this_child <= 0);
        if (workers_may_exit) break;
        if (!thread_just_started) {
            apr_lock_acquire(idle_thread_count_mutex);
            if (idle_thread_count < max_spare_threads) {
                idle_thread_count++;
                apr_lock_release(idle_thread_count_mutex);
            }
            else {
                apr_lock_release(idle_thread_count_mutex);
                break;
            }
        }
        else {
            thread_just_started = 0;
        }

        (void) ap_update_child_status(child_num, thread_num, SERVER_READY,
                                      (request_rec *) NULL);

        apr_lock_acquire(thread_accept_mutex);
        if (workers_may_exit) {
            apr_lock_release(thread_accept_mutex);
            break;
        }
        if ((rv = SAFE_ACCEPT(apr_lock_acquire(process_accept_mutex)))
            != APR_SUCCESS) {
            ap_log_error(APLOG_MARK, APLOG_EMERG, rv, ap_server_conf,
                         "apr_lock_acquire failed. Attempting to shutdown "
                         "process gracefully.");
            workers_may_exit = 1;
        }

        while (!workers_may_exit) {
            apr_int16_t event;
            srv = apr_poll(pollset, &n, -1);

            if (srv != APR_SUCCESS) {
                if (APR_STATUS_IS_EINTR(srv)) {
                    continue;
                }

                /* apr_poll() will only return errors in catastrophic
                 * circumstances. Let's try exiting gracefully, for now. */
                ap_log_error(APLOG_MARK, APLOG_ERR, srv, (const server_rec *)
                             ap_server_conf, "apr_poll: (listen)");
                workers_may_exit = 1;
            }
            if (workers_may_exit) break;

            apr_poll_revents_get(&event, listenfds[0], pollset);
            if (event & APR_POLLIN) {
                /* A process got a signal on the shutdown pipe. Check if we're
                 * the lucky process to die. */
                check_pipe_of_death();
                continue;
            }
            
            apr_poll_revents_get(&event, listenfds[1], pollset);
            if (event & APR_POLLIN || event & APR_POLLOUT) {
                /* This request is from another child in our current process.
                 * We should set a flag here, and then below we will read
                 * two bytes (the socket number and the NULL byte.
                 */
                thread_socket_table[thread_num] = -2;
                goto got_from_other_child;
            }

            if (num_listenfds == 1) {
                sd = ap_listeners->sd;
                goto got_fd;
            }
            else {
                /* find a listener */
                curr_pollfd = last_pollfd;
                do {
                    curr_pollfd++;
                    if (curr_pollfd > num_listenfds) {
                        curr_pollfd = 1;
                    }
                    /* XXX: Should we check for POLLERR? */
                    apr_poll_revents_get(&event, listenfds[curr_pollfd], pollset);
                    if (event & APR_POLLIN) {
                        last_pollfd = curr_pollfd;
                        sd = listenfds[curr_pollfd];
                        goto got_fd;
                    }
                } while (curr_pollfd != last_pollfd);
            }
        }
    got_fd:
        if (!workers_may_exit) {
            if ((rv = apr_accept(&csd, sd, ptrans)) != APR_SUCCESS) {
                ap_log_error(APLOG_MARK, APLOG_ERR, rv, ap_server_conf, "apr_accept");
            }
            if ((rv = SAFE_ACCEPT(apr_lock_release(process_accept_mutex)))
                != APR_SUCCESS) {
                ap_log_error(APLOG_MARK, APLOG_EMERG, rv, ap_server_conf,
                             "apr_lock_release failed. Attempting to shutdown "
                             "process gracefully.");
                workers_may_exit = 1;
            }
            apr_lock_release(thread_accept_mutex);
	    apr_lock_acquire(idle_thread_count_mutex);
            if (idle_thread_count > min_spare_threads) {
                idle_thread_count--;
            }
            else {
                if (!start_thread()) {
                    idle_thread_count--;
                }
            }
            apr_lock_release(idle_thread_count_mutex);
        got_from_other_child:
            if (thread_socket_table[thread_num] == -2) {
                struct msghdr msg;
                struct cmsghdr *cmsg;
                char sockname[80];
                struct iovec iov;
                int ret, sd, dp;

                iov.iov_base = sockname;
                iov.iov_len = 80;

                msg.msg_name = NULL;
                msg.msg_namelen = 0;
                msg.msg_iov = &iov;
                msg.msg_iovlen = 1;

                cmsg = apr_palloc(ptrans, sizeof(*cmsg) + sizeof(sd));
                cmsg->cmsg_len = sizeof(*cmsg) + sizeof(sd);
                msg.msg_control = (caddr_t)cmsg;
                msg.msg_controllen = cmsg->cmsg_len;
                msg.msg_flags = 0;
                
                ret = recvmsg(child_info_table[child_num].sd, &msg, 0);

                memcpy(&dp, CMSG_DATA(cmsg), sizeof(dp));

                thread_socket_table[thread_num] = dp;
                apr_os_sock_put(&csd, &child_info_table[child_num].sd, ptrans);
            }
            if (setjmp(jmpbuffer) != 1) {
                process_socket(ptrans, csd, conn_id);
            }
            else {
                thread_socket_table[thread_num] = -1;
            }  
            requests_this_child--;
	} else {
            if ((rv = SAFE_ACCEPT(apr_lock_release(process_accept_mutex)))
                != APR_SUCCESS) {
                ap_log_error(APLOG_MARK, APLOG_EMERG, rv, ap_server_conf,
                             "apr_lock_release failed. Attempting to shutdown "
                             "process gracefully.");
                workers_may_exit = 1;
            }
            apr_lock_release(thread_accept_mutex);
	    apr_lock_acquire(idle_thread_count_mutex);
            idle_thread_count--;
            apr_lock_release(idle_thread_count_mutex);
	    break;
	}
        apr_pool_clear(ptrans);
    }

    apr_lock_acquire(thread_pool_parent_mutex);
    ap_update_child_status(child_num, thread_num, SERVER_DEAD,
                           (request_rec *) NULL);
    apr_pool_destroy(tpool);
    apr_lock_release(thread_pool_parent_mutex);
    apr_lock_acquire(worker_thread_count_mutex);
    worker_thread_count--;
    worker_thread_free_ids[worker_thread_count] = thread_num;
    if (worker_thread_count == 0) {
        /* All the threads have exited, now finish the shutdown process
         * by signalling the sigwait thread */
        kill(my_pid, SIGTERM);
    }
    apr_lock_release(worker_thread_count_mutex);

    return NULL;
}

/* Set group privileges.
 *
 * Note that we use the username as set in the config files, rather than
 * the lookup of to uid --- the same uid may have multiple passwd entries,
 * with different sets of groups for each.
 */

static int set_group_privs(uid_t uid, gid_t gid)
{
    if (!geteuid()) {
        const char *name;

        /* Get username if passed as a uid */

        struct passwd *ent;

        if ((ent = getpwuid(uid)) == NULL) {
            ap_log_error(APLOG_MARK, APLOG_ALERT, errno, NULL,
                     "getpwuid: couldn't determine user name from uid %u, "
                     "you probably need to modify the User directive",
                     (unsigned)uid);
            return -1;
        }

        name = ent->pw_name;

        /*
         * Set the GID before initgroups(), since on some platforms
         * setgid() is known to zap the group list.
         */
        if (setgid(gid) == -1) {
            ap_log_error(APLOG_MARK, APLOG_ALERT, errno, NULL,
                        "setgid: unable to set group id to Group %u",
                        (unsigned)gid);
            return -1;
        }

        /* Reset `groups' attributes. */

        if (initgroups(name, gid) == -1) {
            ap_log_error(APLOG_MARK, APLOG_ALERT, errno, NULL,
                        "initgroups: unable to set groups for User %s "
                        "and Group %u", name, (unsigned)gid);
            return -1;
        }
    }
    return 0;
}


static int perchild_setup_child(int childnum)
{
    child_info_t *ug = &child_info_table[childnum];

    if (ug->uid == -1 && ug->gid == -1) {
        return unixd_setup_child();
    }
    if (set_group_privs(ug->uid, ug->gid)) {
        return -1;
    }
    /* Only try to switch if we're running as root */
    if (!geteuid() && (
#ifdef _OSD_POSIX
        os_init_job_environment(server_conf, unixd_config.user_name, one_process) != 0 ||
#endif
        setuid(ug->uid) == -1)) {
        ap_log_error(APLOG_MARK, APLOG_ALERT, errno, NULL,
                    "setuid: unable to change to uid: %ld",
                    (long) ug->uid);
        return -1;
    }
    return 0;
}

static int check_signal(int signum)
{
    switch (signum) {
        case SIGTERM:
        case SIGINT:
            just_die(signum);
            return 1;
    }
    return 0;
}                                                                               

static void child_main(int child_num_arg)
{
    int i;
    ap_listen_rec *lr;
    apr_status_t rv;
    apr_thread_t *thread;

    my_pid = getpid();
    child_num = child_num_arg;
    apr_pool_create(&pchild, pconf);

    /*stuff to do before we switch id's, so we have permissions.*/

    rv = SAFE_ACCEPT(apr_lock_child_init(&process_accept_mutex, lock_fname,
                                        pchild));
    if (rv != APR_SUCCESS) {
        ap_log_error(APLOG_MARK, APLOG_EMERG, rv, ap_server_conf,
                     "Couldn't initialize cross-process lock in child");
        clean_child_exit(APEXIT_CHILDFATAL);
    }

    if (perchild_setup_child(child_num)) {
	clean_child_exit(APEXIT_CHILDFATAL);
    }

    ap_run_child_init(pchild, ap_server_conf);

    /*done with init critical section */

    apr_setup_signal_thread();

    requests_this_child = max_requests_per_child;
    
    /* Set up the pollfd array, num_listenfds + 1 for the pipe and 1 for
     * the child socket.
     */
    listenfds = apr_pcalloc(pchild, sizeof(*listenfds) * (num_listenfds + 2));
#if APR_FILES_AS_SOCKETS
    apr_socket_from_file(&listenfds[0], pipe_of_death_in);
#endif

    /* The child socket */
    apr_os_sock_put(&listenfds[1], &child_info_table[child_num].sd, pchild);

    num_listenfds++;
    for (lr = ap_listeners, i = 2; i <= num_listenfds; lr = lr->next, ++i)
        listenfds[i]=lr->sd;

    /* Setup worker threads */

    if (threads_to_start > max_threads) {
        threads_to_start = max_threads;
    }
    idle_thread_count = threads_to_start;
    worker_thread_count = 0;
    for (i = 0; i < max_threads; i++) {
        worker_thread_free_ids[i] = i;
    }
    apr_pool_create(&thread_pool_parent, pchild);
    apr_lock_create(&thread_pool_parent_mutex, APR_MUTEX, APR_INTRAPROCESS, 
                    NULL, pchild);
    apr_lock_create(&idle_thread_count_mutex, APR_MUTEX, APR_INTRAPROCESS, 
                    NULL, pchild);
    apr_lock_create(&worker_thread_count_mutex, APR_MUTEX, APR_INTRAPROCESS,
                    NULL, pchild);
    apr_lock_create(&pipe_of_death_mutex, APR_MUTEX, APR_INTRAPROCESS,