Changeset 3648 for trunk/Ohana/src/libohana/src/glockfile.c

Timestamp:

Apr 1, 2005, 6:32:51 PM (21 years ago)

Author:

eugene

Message:

cleaning up setlockfile2/fsetlockfile

File:

• trunk/Ohana/src/libohana/src/glockfile.c (modified) (8 diffs)

trunk/Ohana/src/libohana/src/glockfile.c

@@ -1 +1 @@
 # include <ohana.h>
 
-/* set a lock on the given file */
 FILE *fsetlockfile (char *filename, double timeout, int type, int *state) {
-  
-  int fd;
-  FILE *f;
-
-  fd = setlockfile2 (filename, timeout, type, state);
-  if (fd == -1) return ((FILE *) NULL);
-
-  /* setlockfile2 returns a pointer to a vile open for update */
-  f = fdopen (fd, "r+");
-  if (f == (FILE *) NULL) {
-    clearlockfile2 (filename, fd, type, state);
-    fprintf (stderr, "can't make stream from descriptor\n");
-    return ((FILE *) NULL);
-  }
-  return (f);
-}
-
-/* clears lock. removes hardlock even if file pointer is not supplied */
-int fclearlockfile (char *filename, FILE *f, int type, int *state) {
-
-  int fd, status;
-
-  fd = -1;
-  if (f != NULL) {
-    fflush (f);
-    fd = fileno (f);
-  }
-  status = clearlockfile2 (filename, fd, type, state);
-  if (f != NULL) fclose (f);
-  return (status);
-}
-
-/* should eventually rewrite these two to use a stream as the basic
-   element and only grab the fileno when needed by fcntl
-   (fileno cannot fail) */
-
-int setlockfile2 (char *filename, double timeout, int type, int *state) {
   
   int i, done, nbytes, status;
   char *lockname, buffer[64];
   char *file, *path;
-  int fd, flock;
-  int filemode;
+  int fd;
+  FILE *f, flock;
   struct stat filestat;
   struct flock filelock;
@@ -51 +13 @@
 
   /* initial values at -1, close if the are set to another value */
-  fd = flock = -1;
-  filemode = S_IRUSR | S_IRGRP | S_IROTH;
   file = path = lockname = (char *) NULL;
-  gettimeofday (&then, (void *) NULL);
 
   /* define lock type */
@@ -65 +24 @@
   case LCK_XCLD:
     filelock.l_type   = F_WRLCK;  /* set an exclusive lock */
-    filemode = S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP | S_IROTH | S_IWOTH;
     break;
   case LCK_SOFT:
     filelock.l_type   = F_RDLCK;  /* set a shared lock */
-    filemode = S_IRUSR | S_IRGRP | S_IROTH;
     break;
   default:
@@ -85 +42 @@
   }
   
-  /* try to open file */
-  fd = open (filename, O_RDWR | O_CREAT, filemode);
-  if (fd == -1) {
+  /* try to open file (create if it does not exist) */
+  f = fopen (filename, "w+");
+  if (f == NULL) {
     *state = LCK_ACCESS;
     goto failure;
   }
+  fd = fileno (f);
 
   /* we first try to set a FS level lock on the file */
-  for (done = 0; !done; ) {
+  gettimeofday (&then, (void *) NULL);
+  while (1) {
+    /* try to lock file */
+    if (fcntl (fd, F_SETLK, &filelock) != -1) goto got_lock;
 
     /* check for timeout */
@@ -101 +62 @@
       goto failure;
     }
-    usleep (10000); /* 10 ms is min */
-
-    /* try to lock file */
-    if (fcntl (fd, F_SETLK, &filelock) != -1) done = 1;
-  }
+    usleep (10000); /* 10 ms is min utime */
+  }
+got_lock:
 
   if (type == LCK_HARD) {
-    /* we've locked filename, now check lockname */ 
-
-    /* locking the lockfile before checking / setting contents will 
-       ensure the data is synced across NFS */
-    
+    /* we've locked filename, now check lockfile */ 
+
     /* set up name to lockfile */
     path = pathname (filename);
@@ -120 +76 @@
 
     /* try to open lockfile */
-    flock = open (lockname, O_RDWR | O_CREAT, filemode);
-    if (flock == -1) {
+    flock = fopen (lockname, "w+");
+    if (flock == NULL) {
       *state = LCK_HARDLCK;
       goto failure;
-    }
-    
-    /* try a few times to lock lockfile */
-    for (i = 0; (i < 20) && (fcntl (flock, F_SETLK, &filelock) == -1); i++) {
-      usleep (10000);
-    }
+      /***** this one has left the file locked ****/
+    }
+    fd = fileno (flock);
+    
+    /* try a few times to lock lockfile (locking the lockfile before checking
+       the contents will ensure the data is synced across NFS) */
+    for (i = 0; (i < 20) && (fcntl (fd, F_SETLK, &filelock) == -1); i++) usleep (10000);
     if (i == 20) {
       *state = LCK_HARDLCK + 10;
       goto failure;
-    }
-    
-    /* we've locked the file, now read the contents */
-    nbytes = read (flock, buffer, 4);
+      /***** this one has left the file locked ****/
+    }
+    
+    /* we've locked the lockfile, now read the contents */
+    nbytes = fread (buffer, 1, 4, flock);
     if (nbytes == 4) { /* lock file has a word in it */
       buffer[4] = 0;
@@ -142 +100 @@
         *state = LCK_HARDLCK + 20;
         goto failure;
+        /*** lock file is still 
       }
+      /* note that we don't care if the lockfile has random garbage */
     }
     
@@ -187 +147 @@
 }
   
+/* clears lock. removes hardlock even if file pointer is not supplied */
+int fclearlockfile (char *filename, FILE *f, int type, int *state) {
+
+  int fd, status;
+
+  fd = -1;
+  if (f != NULL) {
+    fflush (f);
+    fd = fileno (f);
+  }
+  status = clearlockfile2 (filename, fd, type, state);
+  if (f != NULL) fclose (f);
+  return (status);
+}
+
 /* if we pass in -1, all we can do is clear the hardlock */
 int clearlockfile2 (char *filename, int fd, int type, int *state) {