file locking with flock(), plus error return from Sync().

SCCS-vsn: games/sail/sync.c 2.5

diff --git a/usr/src/games/sail/sync.c b/usr/src/games/sail/sync.c
index 059d9f7..27c971a 100644 (file)
--- a/usr/src/games/sail/sync.c
+++ b/usr/src/games/sail/sync.c
@@ -1,8 +1,10 @@
 #ifndef lint
 #ifndef lint

-static char *sccsid = "@(#)sync.c      2.4 84/01/27";
+static char *sccsid = "@(#)sync.c      2.5 84/02/23";

 #endif
 
 #include "externs.h"
 #endif
 
 #include "externs.h"

+#include <sys/file.h>
+#include <sys/errno.h>

 
 static char sync_buf[BUFSIZE];
 static char *sync_bp = sync_buf;
 
 static char sync_buf[BUFSIZE];
 static char *sync_bp = sync_buf;


@@ -43,6 +45,8 @@ sync_exists(game)
        if (stat(buf, &s) < 0)
                return 0;
        if (s.st_mtime < t - 60*60*2) {         /* 2 hours */
        if (stat(buf, &s) < 0)
                return 0;
        if (s.st_mtime < t - 60*60*2) {         /* 2 hours */

+               (void) unlink(buf);
+               (void) sprintf(buf, LF, game);

                (void) unlink(buf);
                return 0;
        } else
                (void) unlink(buf);
                return 0;
        } else


@@ -96,24 +100,52 @@ int a, b, c, d;
        sync_bp--;
        if (sync_bp >= &sync_buf[sizeof sync_buf])
                abort();
        sync_bp--;
        if (sync_bp >= &sync_buf[sizeof sync_buf])
                abort();

-       sync_update(type, ship, a, b, c, d);
+       (void) sync_update(type, ship, a, b, c, d);

 }
 
 Sync()
 {
        int (*sig1)(), (*sig2)();
 }
 
 Sync()
 {
        int (*sig1)(), (*sig2)();

-       int type, shipnum, isstr, a, b, c, d;
-       char buf[60];
-       register char *p = buf;

        int n;
        int n;

+       int type, shipnum, isstr, a, b, c, d;
+       char buf[80];
+       char erred = 0;
+       extern errno;

 
        sig1 = signal(SIGHUP, SIG_IGN);
        sig2 = signal(SIGINT, SIG_IGN);
 
        sig1 = signal(SIGHUP, SIG_IGN);
        sig2 = signal(SIGINT, SIG_IGN);

-       for (n = 0; link(sync_file, sync_lock) < 0 && n < 30; n++)
+       for (n = 0; n < 30; n++) {
+#ifdef LOCK_EX
+               if (flock(fileno(sync_fp), LOCK_EX|LOCK_NB) >= 0)
+                       break;
+               if (errno != EWOULDBLOCK)
+                       return -1;
+#else
+               if (link(sync_file, sync_lock) >= 0)
+                       break;
+               if (errno != EEXIST)
+                       return -1;
+#endif

                sleep(2);
                sleep(2);

+       }
+       if (n >= 30)
+               return -1;

        (void) fseek(sync_fp, sync_seek, 0);
        (void) fseek(sync_fp, sync_seek, 0);

-       while (fscanf(sync_fp, "%d%d%d", &type, &shipnum, &isstr) != EOF) {
+       for (;;) {
+               switch (fscanf(sync_fp, "%d%d%d", &type, &shipnum, &isstr)) {
+               case 3:
+                       break;
+               case EOF:
+                       goto out;
+               default:
+                       goto bad;
+               }
+               if (shipnum < 0 || shipnum >= cc->vessels)
+                       goto bad;
+               if (isstr != 0 && isstr != 1)
+                       goto bad;

                if (isstr) {
                if (isstr) {

+                       register char *p;

                        for (p = buf;;) {
                                switch (*p++ = getc(sync_fp)) {
                                case '\n':
                        for (p = buf;;) {
                                switch (*p++ = getc(sync_fp)) {
                                case '\n':


@@ -121,6 +153,8 @@ Sync()
                                case EOF:
                                        break;
                                default:
                                case EOF:
                                        break;
                                default:

+                                       if (p >= buf + sizeof buf)
+                                               p--;

                                        continue;
                                }
                                break;
                                        continue;
                                }
                                break;


@@ -131,19 +165,29 @@ Sync()
                        a = (int)p;
                        b = c = d = 0;
                } else
                        a = (int)p;
                        b = c = d = 0;
                } else

-                       (void) fscanf(sync_fp, "%d%d%d%d", &a, &b, &c, &d);
-               sync_update(type, SHIP(shipnum), a, b, c, d);
+                       if (fscanf(sync_fp, "%d%d%d%d", &a, &b, &c, &d) != 4)
+                               goto bad;
+               if (sync_update(type, SHIP(shipnum), a, b, c, d) < 0)
+                       goto bad;

        }
        }

-       if (sync_bp != sync_buf) {
+bad:
+       erred++;
+out:
+       if (!erred && sync_bp != sync_buf) {

                (void) fseek(sync_fp, 0L, 2);
                (void) fputs(sync_buf, sync_fp);
                (void) fflush(sync_fp);
                sync_bp = sync_buf;
        }
        sync_seek = ftell(sync_fp);
                (void) fseek(sync_fp, 0L, 2);
                (void) fputs(sync_buf, sync_fp);
                (void) fflush(sync_fp);
                sync_bp = sync_buf;
        }
        sync_seek = ftell(sync_fp);

+#ifdef LOCK_EX
+       (void) flock(fileno(sync_fp), LOCK_UN);
+#else

        (void) unlink(sync_lock);
        (void) unlink(sync_lock);

+#endif

        (void) signal(SIGHUP, sig1);
        (void) signal(SIGINT, sig2);
        (void) signal(SIGHUP, sig1);
        (void) signal(SIGINT, sig2);

+       return erred ? -1 : 0;

 }
 
 sync_update(type, ship, a, b, c, d)
 }
 
 sync_update(type, ship, a, b, c, d)


@@ -326,11 +370,16 @@ int a, b, c, d;
                people++;
                break;
        case W_END:
                people++;
                break;
        case W_END:

-               (void) strcpy(ship->file->captain, "");
+               *ship->file->captain = 0;
+               ship->file->points = 0;

                people--;
                break;
                people--;
                break;

-       default:
-               fprintf(stderr, "sync_update: unknown type %d\n", type);
+       case W_DDEAD:
+               hasdriver = 0;

                break;
                break;

+       default:
+               fprintf(stderr, "sync_update: unknown type %d\r\n", type);
+               return -1;

        }
        }

+       return 0;

 }
 }