Fix PRNG seeding to resist guessing

[empserver] / src / server / main.c

diff --git a/src/server/main.c b/src/server/main.c
index d13920ba8e3c5335a1d72dfe435a013f846a283e..52c4c8cc3fb2eb72494b8cf155e96979aaf9683c 100644 (file)
--- a/src/server/main.c
+++ b/src/server/main.c
@@ -1,11 +1,11 @@
 /*
  *  Empire - A multi-player, client/server Internet based war game.
- *  Copyright (C) 1986-2010, Dave Pare, Jeff Bailey, Thomas Ruschak,
- *                           Ken Stevens, Steve McClure
+ *  Copyright (C) 1986-2013, Dave Pare, Jeff Bailey, Thomas Ruschak,
+ *                Ken Stevens, Steve McClure, Markus Armbruster
  *
- *  This program is free software; you can redistribute it and/or modify
+ *  Empire is free software: you can redistribute it and/or modify
  *  it under the terms of the GNU General Public License as published by
- *  the Free Software Foundation; either version 2 of the License, or
+ *  the Free Software Foundation, either version 3 of the License, or
  *  (at your option) any later version.
  *
  *  This program is distributed in the hope that it will be useful,
@@ -14,8 +14,7 @@
  *  GNU General Public License for more details.
  *
  *  You should have received a copy of the GNU General Public License
- *  along with this program; if not, write to the Free Software
- *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ *  along with this program.  If not, see <http://www.gnu.org/licenses/>.
  *
  *  ---
  *
@@ -32,7 +31,7 @@
  *     Steve McClure, 1996, 1998
  *     Doug Hay, 1998
  *     Ron Koenderink, 2004-2009
- *     Markus Armbruster, 2005-2009
+ *     Markus Armbruster, 2005-2012
  */
 
 #include <config.h>
@@ -51,15 +50,13 @@
 #include "sys/socket.h"
 #endif
 
+#include "chance.h"
 #include "empio.h"
 #include "empthread.h"
 #include "file.h"
 #include "journal.h"
-#include "land.h"
 #include "match.h"
 #include "misc.h"
-#include "nat.h"
-#include "nuke.h"
 #include "optlist.h"
 #include "plane.h"
 #include "player.h"
@@ -67,11 +64,11 @@
 #include "prototypes.h"
 #include "sect.h"
 #include "server.h"
-#include "ship.h"
 #include "version.h"
 
 static void ignore(void);
 static void crash_dump(void);
+static void init_server(unsigned, int);
 static void create_pidfile(char *, pid_t);
 
 #if defined(_WIN32)
@@ -79,10 +76,16 @@ static void loc_NTInit(void);
 #endif
 
 /*
- * Lock to synchronize player threads with update and shutdown.
- * Update and shutdown takes it exclusive, commands take it shared.
+ * Lock to synchronize player threads with update.
+ * Update holds it exclusive, commands hold it shared.
  */
-empth_rwlock_t *play_lock;
+empth_rwlock_t *update_lock;
+/*
+ * Lock to synchronize player threads with shutdown.
+ * Shutdown holds it exclusive, player threads in state PS_PLAYING
+ * hold it shared.
+ */
+empth_rwlock_t *shutdown_lock;
 
 static char pidfname[] = "server.pid";
 
@@ -138,8 +141,10 @@ main(int argc, char **argv)
     int remove_service_set = 0;
 #endif
     char *config_file = NULL;
+    int force_bad_state = 0;
     int op, idx, sig;
-    unsigned seed = time(NULL);
+    unsigned seed = 0;
+    int seed_set = 0;
 
     oops_handler = ignore;
 
@@ -148,7 +153,7 @@ main(int argc, char **argv)
 #else
 # define XOPTS
 #endif
-    while ((op = getopt(argc, argv, "de:E:hpsR:v" XOPTS)) != EOF) {
+    while ((op = getopt(argc, argv, "de:E:FhpsR:v" XOPTS)) != EOF) {
        switch (op) {
        case 'p':
            flags |= EMPTH_PRINT;
@@ -168,6 +173,9 @@ main(int argc, char **argv)
            }
            oops_handler = oops_hndlr[idx];
            break;
+       case 'F':
+           force_bad_state = 1;
+           break;
 #if defined(_WIN32)
        case 'I':
            service_name = optarg;
@@ -187,6 +195,7 @@ main(int argc, char **argv)
            break;
        case 'R':
            seed = strtoul(optarg, NULL, 10);
+           seed_set = 1;
            break;
        case 'v':
            printf("%s\n\n%s", version, legal);
@@ -247,7 +256,9 @@ main(int argc, char **argv)
        return install_service(program_name, service_name, config_file);
 #endif /* _WIN32 */
 
-    init_server(seed);
+    if (!seed_set)
+       seed = pick_seed();
+    init_server(seed, force_bad_state);
 
 #if defined(_WIN32)
     if (daemonize != 0) {
@@ -280,7 +291,6 @@ main(int argc, char **argv)
     }
 #endif /* !_WIN32 */
     start_server(flags);
-    journal_prng(seed);
 
     for (;;) {
        sig = empth_wait_for_signal();
@@ -341,18 +351,21 @@ crash_dump(void)
 /*
  * Initialize for serving, acquire resources.
  */
-void
-init_server(unsigned seed)
+static void
+init_server(unsigned seed, int force_bad_state)
 {
-    srandom(seed);
+    seed_prng(seed);
 #if defined(_WIN32)
     loc_NTInit();
 #endif
     player_init();
-    ef_init_srv();
+    ef_init_srv(force_bad_state);
     io_init();
     init_nreport();
 
+    if (journal_startup() < 0)
+       exit(1);
+    journal_prng(seed);
     loginit("server");
 }
 
@@ -371,8 +384,10 @@ start_server(int flags)
 
     empth_init((void **)&player, flags);
 
-    if (journal_startup() < 0)
-       exit(1);
+    update_lock = empth_rwlock_create("Update");
+    shutdown_lock = empth_rwlock_create("Shutdown");
+    if (!update_lock || !shutdown_lock)
+       exit_nomem();
 
     market_init();
     update_init();
@@ -406,8 +421,8 @@ void
 shutdwn(int sig)
 {
     struct player *p;
-    time_t now;
-    int i, queues_drained;
+    time_t now = time(NULL);
+    int i;
 
     logerror("Shutdown commencing (cleaning up threads.)");
 
@@ -415,34 +430,25 @@ shutdwn(int sig)
        if (p->state != PS_PLAYING)
            continue;
        pr_flash(p, "Server shutting down...\n");
-       p->state = PS_SHUTDOWN;
+       io_set_eof(p->iop);
+       p->aborted = 1;
        p->may_sleep = PLAYER_SLEEP_NEVER;
-       p->aborted++;
        if (p->command) {
            pr_flash(p, "Shutdown aborting command\n");
        }
        empth_wakeup(p->proc);
     }
-    empth_rwlock_wrlock(play_lock);
 
-    now = time(NULL);
+    empth_rwlock_wrlock(shutdown_lock);
     empth_yield();
-    for (i = 1; i <= 3; i++) {
-       queues_drained = 1;
-       for (p = player_next(NULL); p; p = player_next(p)) {
-           if (io_outputwaiting(p->iop))
-               queues_drained = 0;
-       }
-       if (queues_drained)
-           break;
-       logerror("Waiting for player output to drain\n");
+
+    for (i = 1; i <= 3 && player_next(NULL); i++) {
+       logerror("Waiting for player threads to terminate\n");
        empth_sleep(now + i);
     }
 
-    for (p = player_next(NULL); p; p = player_next(p)) {
-       if (io_outputwaiting(p->iop))
-           logerror("Output for player %d lost", p->cnum);
-    }
+    for (p = player_next(NULL); p; p = player_next(p))
+       logerror("Player %d lingers, output might be lost", p->cnum);
 
     if (sig)
        logerror("Server shutting down on signal %d", sig);