[svn-r18395] Purpose: Fix links.c failure

Description:
The core file driver previously matched files only based on the name used to
open them, even when a backing store is used.  This caused problems in the
failing test when it traversed an external link to itself, and did not recognize
that it was the same file.  Similar tests in links.c were skipped when the core
file driver was used.  The failure was previously masked by inappropriate file
flushes caused by external link traversal.  Added code to the core file driver
to keep track of low level file information of the backings store to allow for
accurate recognition of duplicate files.  Also re-enabled all links.c tests for
the core file driver.

Tested: Fedora (core and sec2 drivers; no time for full commit test, will
monitor daily tests)

1 files changed, 107 insertions, 18 deletions

diff --git a/src/H5FDcore.c b/src/H5FDcore.c
index 1333995..3a56524 100644
--- a/src/H5FDcore.c
+++ b/src/H5FDcore.c
@@ -52,6 +52,31 @@ typedef struct H5FD_core_t {
     size_t	increment;		/*multiples for mem allocation	*/
     hbool_t	backing_store;		/*write to file name on flush	*/
     int		fd;			/*backing store file descriptor	*/
+    /* Information for determining uniqueness of a file with a backing store */
+#ifndef _WIN32
+    /*
+     * On most systems the combination of device and i-node number uniquely
+     * identify a file.
+     */
+    dev_t       device;                 /*file device number            */
+#ifdef H5_VMS
+    ino_t       inode[3];               /*file i-node number            */
+#else
+    ino_t       inode;                  /*file i-node number            */
+#endif /*H5_VMS*/
+#else
+    /*
+     * On _WIN32 the low-order word of a unique identifier associated with the
+     * file and the volume serial number uniquely identify a file. This number
+     * (which, both? -rpm) may change when the system is restarted or when the
+     * file is opened. After a process opens a file, the identifier is
+     * constant until the file is closed. An application can use this
+     * identifier and the volume serial number to determine whether two
+     * handles refer to the same file.
+     */
+    DWORD fileindexlo;
+    DWORD fileindexhi;
+#endif
     hbool_t	dirty;			/*changes not saved?		*/
 } H5FD_core_t;
 
@@ -391,6 +416,10 @@ H5FD_core_open(const char *name, unsigned flags, hid_t fapl_id,
     H5FD_core_t		*file=NULL;
     H5FD_core_fapl_t	*fa=NULL;
     H5P_genplist_t *plist;      /* Property list pointer */
+#ifdef _WIN32
+    HFILE filehandle;
+    struct _BY_HANDLE_FILE_INFORMATION fileinfo;
+#endif
     h5_stat_t		sb;
     int			fd=-1;
     H5FD_t		*ret_value;
@@ -415,11 +444,14 @@ H5FD_core_open(const char *name, unsigned flags, hid_t fapl_id,
     if(H5F_ACC_CREAT & flags) o_flags |= O_CREAT;
     if(H5F_ACC_EXCL & flags) o_flags |= O_EXCL;
 
-    /* Open backing store.  The only case that backing store is off is when
-     * the backing_store flag is off and H5F_ACC_CREAT is on. */
+    /* Open backing store, and get stat() from file.  The only case that backing
+     * store is off is when  the backing_store flag is off and H5F_ACC_CREAT is
+     * on. */
     if(fa->backing_store || !(H5F_ACC_CREAT & flags)) {
         if(fa && (fd = HDopen(name, o_flags, 0666)) < 0)
             HGOTO_ERROR(H5E_FILE, H5E_CANTOPENFILE, NULL, "unable to open file")
+        if(HDfstat(fd, &sb) < 0)
+            HSYS_GOTO_ERROR(H5E_FILE, H5E_BADFILE, NULL, "unable to fstat file")
     } /* end if */
 
     /* Create the new file struct */
@@ -439,13 +471,31 @@ H5FD_core_open(const char *name, unsigned flags, hid_t fapl_id,
     /* If save data in backing store. */
     file->backing_store = fa->backing_store;
 
+    if(fd >= 0) {
+        /* Retrieve information for determining uniqueness of file */
+#ifdef _WIN32
+        filehandle = _get_osfhandle(fd);
+        (void)GetFileInformationByHandle((HANDLE)filehandle, &fileinfo);
+        file->fileindexhi = fileinfo.nFileIndexHigh;
+        file->fileindexlo = fileinfo.nFileIndexLow;
+#else /* _WIN32 */
+        file->device = sb.st_dev;
+#ifdef H5_VMS
+        file->inode[0] = sb.st_ino[0];
+        file->inode[1] = sb.st_ino[1];
+        file->inode[2] = sb.st_ino[2];
+#else
+        file->inode = sb.st_ino;
+#endif /* H5_VMS */
+
+#endif /* _WIN32 */
+    } /* end if */
+
     /* If an existing file is opened, load the whole file into memory. */
     if(!(H5F_ACC_CREAT & flags)) {
         size_t size;
 
-        /* stat() file to retrieve its size */
-        if(HDfstat(file->fd, &sb) < 0)
-            HSYS_GOTO_ERROR(H5E_FILE, H5E_BADFILE, NULL, "unable to fstat file")
+        /* Retrieve file size */
 	size = (size_t)sb.st_size;
 
         /* Check if we should allocate the memory buffer and read in existing data */
@@ -529,6 +579,11 @@ done:
  *              Thursday, July 29, 1999
  *
  * Modifications:
+ *              Neil Fortner
+ *              Tuesday, March 9, 2010
+ *              Modified function to compare low level file information if
+ *              a backing store is opened for both files, similar to the
+ *              sec2 file driver.
  *
  *-------------------------------------------------------------------------
  */
@@ -537,28 +592,62 @@ H5FD_core_cmp(const H5FD_t *_f1, const H5FD_t *_f2)
 {
     const H5FD_core_t	*f1 = (const H5FD_core_t*)_f1;
     const H5FD_core_t	*f2 = (const H5FD_core_t*)_f2;
-    int			ret_value;
+    int			ret_value = 0;
 
     FUNC_ENTER_NOAPI(H5FD_core_cmp, FAIL)
 
-    if (NULL==f1->name && NULL==f2->name) {
-        if (f1<f2)
+    if(f1->fd >= 0 && f2->fd >= 0) {
+        /* Compare low level file information for backing store */
+#ifdef _WIN32
+        if (f1->fileindexhi < f2->fileindexhi) HGOTO_DONE(-1)
+        if (f1->fileindexhi > f2->fileindexhi) HGOTO_DONE(1)
+
+        if (f1->fileindexlo < f2->fileindexlo) HGOTO_DONE(-1)
+        if (f1->fileindexlo > f2->fileindexlo) HGOTO_DONE(1)
+
+#else
+#ifdef H5_DEV_T_IS_SCALAR
+        if (f1->device < f2->device) HGOTO_DONE(-1)
+        if (f1->device > f2->device) HGOTO_DONE(1)
+#else /* H5_DEV_T_IS_SCALAR */
+        /* If dev_t isn't a scalar value on this system, just use memcmp to
+         * determine if the values are the same or not.  The actual return value
+         * shouldn't really matter...
+         */
+        if(HDmemcmp(&(f1->device),&(f2->device),sizeof(dev_t))<0) HGOTO_DONE(-1)
+        if(HDmemcmp(&(f1->device),&(f2->device),sizeof(dev_t))>0) HGOTO_DONE(1)
+#endif /* H5_DEV_T_IS_SCALAR */
+
+#ifndef H5_VMS
+        if (f1->inode < f2->inode) HGOTO_DONE(-1)
+        if (f1->inode > f2->inode) HGOTO_DONE(1)
+#else
+        if(HDmemcmp(&(f1->inode),&(f2->inode),3*sizeof(ino_t))<0) HGOTO_DONE(-1)
+        if(HDmemcmp(&(f1->inode),&(f2->inode),3*sizeof(ino_t))>0) HGOTO_DONE(1)
+#endif /* H5_VMS */
+
+#endif /*_WIN32*/
+    } /* end if */
+    else {
+        if (NULL==f1->name && NULL==f2->name) {
+            if (f1<f2)
+                HGOTO_DONE(-1)
+            if (f1>f2)
+                HGOTO_DONE(1)
+            HGOTO_DONE(0)
+        } /* end if */
+
+        if (NULL==f1->name)
             HGOTO_DONE(-1)
-        if (f1>f2)
+        if (NULL==f2->name)
             HGOTO_DONE(1)
-        HGOTO_DONE(0)
-    }
 
-    if (NULL==f1->name)
-        HGOTO_DONE(-1)
-    if (NULL==f2->name)
-        HGOTO_DONE(1)
-
-    ret_value = HDstrcmp(f1->name, f2->name);
+        ret_value = HDstrcmp(f1->name, f2->name);
+    } /* end else */
 
 done:
     FUNC_LEAVE_NOAPI(ret_value)
-}
+} /* end H5FD_core_cmp() */
 
 
 /*-------------------------------------------------------------------------