[svn-r15367] Description:

    Add check to avoid mounting the a file on a group twice, then the mounts
are done on the same HDF5 file, but opened with separate H5Fopen calls.

    Also add new 'mounted' flag to the H5G_info_t struct, queried with the
H5Gget_info() API call, to allow applications to detect and avoid this
situation.

    This probably fixes Bz#1070 also, I'll check with Dan Anov (who reported
a different sort of behavior, but seems to have the same underlying problem).

Tested on:
    Mac OS X/32 10.5.4 (amazon)
    Linux/64 2.6 (chicago)

6 files changed, 198 insertions, 3 deletions

diff --git a/src/H5Fmount.c b/src/H5Fmount.c
index 470d323..c96c920 100644
--- a/src/H5Fmount.c
+++ b/src/H5Fmount.c
@@ -135,7 +135,7 @@ H5F_mount(H5G_loc_t *loc, const char *name, H5F_t *child,
     HDassert(child);
     HDassert(TRUE == H5P_isa_class(plist_id, H5P_FILE_MOUNT));
 
-    /* Set up dataset location to fill in */
+    /* Set up group location to fill in */
     mp_loc.oloc = &mp_oloc;
     mp_loc.path = &mp_path;
     H5G_loc_reset(&mp_loc);
@@ -161,6 +161,10 @@ H5F_mount(H5G_loc_t *loc, const char *name, H5F_t *child,
     if(NULL == (mount_point = H5G_open(&mp_loc, dxpl_id)))
         HGOTO_ERROR(H5E_FILE, H5E_MOUNT, FAIL, "mount point not found")
 
+    /* Check if the proposed mount point group is already a mount point */
+    if(H5G_MOUNTED(mount_point))
+	HGOTO_ERROR(H5E_FILE, H5E_MOUNT, FAIL, "mount point is already in use")
+
     /* Retrieve information from the mount point group */
     /* (Some of which we had before but was reset in mp_loc when the group
      *  "took over" the group location - QAK)
diff --git a/src/H5G.c b/src/H5G.c
index 0fa2c1c..e04402e 100644
--- a/src/H5G.c
+++ b/src/H5G.c
@@ -1526,6 +1526,30 @@ H5G_mount(H5G_t *grp)
 
 
 /*-------------------------------------------------------------------------
+ * Function:	H5G_mounted
+ *
+ * Purpose:	Retrieves the 'mounted' flag for a group
+ *
+ * Return:	Non-negative on success/Negative on failure
+ *
+ * Programmer:	Quincey Koziol
+ *		Tuesday, July 15, 2008
+ *
+ *-------------------------------------------------------------------------
+ */
+hbool_t
+H5G_mounted(H5G_t *grp)
+{
+    FUNC_ENTER_NOAPI_NOINIT_NOFUNC(H5G_mounted)
+
+    /* Check args */
+    HDassert(grp && grp->shared);
+
+    FUNC_LEAVE_NOAPI(grp->shared->mounted)
+} /* end H5G_mounted() */
+
+
+/*-------------------------------------------------------------------------
  * Function:	H5G_unmount
  *
  * Purpose:	Resets the 'mounted' flag for a group
diff --git a/src/H5Gobj.c b/src/H5Gobj.c
index 8ca8c52..e04c12d 100644
--- a/src/H5Gobj.c
+++ b/src/H5Gobj.c
@@ -702,6 +702,10 @@ done:
 herr_t
 H5G_obj_info(H5O_loc_t *oloc, H5G_info_t *grp_info, hid_t dxpl_id)
 {
+    H5G_t *grp = NULL;                  /* Group to query */
+    H5G_loc_t   grp_loc;                /* Entry of group to be queried */
+    H5G_name_t  grp_path;            	/* Group hier. path */
+    H5O_loc_t   grp_oloc;            	/* Group object location */
     H5O_linfo_t	linfo;		        /* Link info message */
     herr_t ret_value = SUCCEED;         /* Return value */
 
@@ -711,6 +715,22 @@ H5G_obj_info(H5O_loc_t *oloc, H5G_info_t *grp_info, hid_t dxpl_id)
     HDassert(oloc);
     HDassert(grp_info);
 
+    /* Set up group location to fill in */
+    grp_loc.oloc = &grp_oloc;
+    grp_loc.path = &grp_path;
+    H5G_loc_reset(&grp_loc);
+
+    /* Deep copy (duplicate) of the group location object */
+    if(H5O_loc_copy(&grp_oloc, oloc, H5_COPY_DEEP) < 0)
+        HGOTO_ERROR(H5E_SYM, H5E_CANTCOPY, FAIL, "can't copy object location")
+
+    /* Open the group */
+    if(NULL == (grp = H5G_open(&grp_loc, dxpl_id)))
+        HGOTO_ERROR(H5E_FILE, H5E_MOUNT, FAIL, "mount point not found")
+
+    /* Get information from the group */
+    grp_info->mounted = H5G_MOUNTED(grp);
+
     /* Attempt to get the link info for this group */
     if(H5G_obj_get_linfo(oloc, &linfo, dxpl_id)) {
         /* Retrieve the information about the links */
@@ -737,6 +757,10 @@ H5G_obj_info(H5O_loc_t *oloc, H5G_info_t *grp_info, hid_t dxpl_id)
     } /* end else */
 
 done:
+    /* Clean up resources */
+    if(grp && H5G_close(grp) < 0)
+        HDONE_ERROR(H5E_SYM, H5E_CANTCLOSEOBJ, FAIL, "unable to close queried group")
+
     FUNC_LEAVE_NOAPI(ret_value)
 } /* end H5G_obj_info() */
 
diff --git a/src/H5Gprivate.h b/src/H5Gprivate.h
index c54f11d..ab6abc1 100644
--- a/src/H5Gprivate.h
+++ b/src/H5Gprivate.h
@@ -101,6 +101,12 @@
                                                     H5G_CRT_GINFO_EST_NAME_LEN \
                                                 }
 
+/* If the module using this macro is allowed access to the private variables, access them directly */
+#ifdef H5G_PACKAGE
+#define H5G_MOUNTED(G)              ((G)->shared->mounted)
+#else /* H5G_PACKAGE */
+#define H5G_MOUNTED(G)              (H5G_mounted(G))
+#endif /* H5G_PACKAGE */
 
 /* Type of operation being performed for call to H5G_name_replace() */
 typedef enum {
@@ -158,6 +164,7 @@ H5_DLL herr_t H5G_close(H5G_t *grp);
 H5_DLL herr_t H5G_free_grp_name(H5G_t *grp);
 H5_DLL herr_t H5G_get_shared_count(H5G_t *grp);
 H5_DLL herr_t H5G_mount(H5G_t *grp);
+H5_DLL hbool_t H5G_mounted(H5G_t *grp);
 H5_DLL herr_t H5G_unmount(H5G_t *grp);
 #ifndef H5_NO_DEPRECATED_SYMBOLS
 H5_DLL H5G_obj_t H5G_map_obj_type(H5O_type_t obj_type);
diff --git a/src/H5Gpublic.h b/src/H5Gpublic.h
index e818e72..5ba7050 100644
--- a/src/H5Gpublic.h
+++ b/src/H5Gpublic.h
@@ -61,6 +61,7 @@ typedef struct H5G_info_t {
     H5G_storage_type_t 	storage_type;	/* Type of storage for links in group */
     hsize_t 	nlinks;		        /* Number of links in group */
     int64_t     max_corder;             /* Current max. creation order value for group */
+    hbool_t     mounted;                /* Whether group has a file mounted on it */
 } H5G_info_t;
 
 /********************/
diff --git a/test/mount.c b/test/mount.c
index e6aa881..1898a36 100644
--- a/test/mount.c
+++ b/test/mount.c
@@ -168,9 +168,9 @@ test_basic(hid_t fapl)
 static int
 test_illegal(hid_t fapl)
 {
-    hid_t	file1 = -1, file2 = -1, file3 = -1, mnt = -1;
-    herr_t	status;
+    hid_t	file1 = -1, file2 = -1, file3 = -1, file4 = -1, mnt = -1;
     char	filename1[1024], filename2[1024], filename3[1024];
+    herr_t	status;
 
     TESTING("illegal mount operations");
     h5_fixname(FILENAME[0], fapl, filename1, sizeof filename1);
@@ -183,6 +183,8 @@ test_illegal(hid_t fapl)
             (file2 = H5Fopen(filename2, H5F_ACC_RDONLY, fapl)) < 0 ||
             (file3 = H5Fopen(filename3, H5F_ACC_RDONLY, fapl)) < 0)
 	FAIL_STACK_ERROR
+    if((file4 = H5Fopen(filename3, H5F_ACC_RDONLY, fapl)) < 0)
+	FAIL_STACK_ERROR
 
     /* Try mounting a file on itself */
     H5E_BEGIN_TRY {
@@ -212,11 +214,32 @@ test_illegal(hid_t fapl)
     if(H5Funmount(mnt, ".") < 0) FAIL_STACK_ERROR
     if(H5Gclose(mnt) < 0) FAIL_STACK_ERROR
 
+    /*
+     * Try mounting the same file opened twice at the same place.
+     *
+     * We have to open the mount point before we mount the first file or we'll
+     * end up mounting file4 at the root of file3 and the mount will succeed.
+     */
+    if((mnt = H5Gopen2(file1, "/mnt1", H5P_DEFAULT)) < 0) FAIL_STACK_ERROR
+    if(H5Fmount(mnt, ".", file3, H5P_DEFAULT) < 0) FAIL_STACK_ERROR
+    H5E_BEGIN_TRY {
+	status = H5Fmount(mnt, ".", file4, H5P_DEFAULT);
+    } H5E_END_TRY;
+    if(status >= 0) {
+	H5_FAILED();
+	puts("    Mounting same file opened twice at one mount point should have failed.");
+	TEST_ERROR
+    } /* end if */
+    if(H5Funmount(mnt, ".") < 0) FAIL_STACK_ERROR
+    if(H5Gclose(mnt) < 0) FAIL_STACK_ERROR
+
+
 
     /* Close everything and return */
     if(H5Fclose(file1) < 0) FAIL_STACK_ERROR
     if(H5Fclose(file2) < 0) FAIL_STACK_ERROR
     if(H5Fclose(file3) < 0) FAIL_STACK_ERROR
+    if(H5Fclose(file4) < 0) FAIL_STACK_ERROR
 
     PASSED();
     return 0;
@@ -227,12 +250,123 @@ error:
 	H5Fclose(file1);
 	H5Fclose(file2);
 	H5Fclose(file3);
+	H5Fclose(file4);
     } H5E_END_TRY;
     return 1;
 } /* end test_illegal() */
 
 
 /*-------------------------------------------------------------------------
+ * Function:	test_samefile
+ *
+ * Purpose:	Test opening the same file twice and then mounting another
+ *              file on each.
+ *
+ * Return:	Success:	0
+ *		Failure:	number of errors
+ *
+ * Programmer:	Quincey Koziol
+ *              Tuesday, July 15, 2008
+ *
+ *-------------------------------------------------------------------------
+ */
+static int
+test_samefile(hid_t fapl)
+{
+    hid_t	file1a = -1, file1b = -1, file2 = -1, file3 = -1;
+    hid_t	mnt1a = -1, mnt1b = -1;
+    char	filename1[1024], filename2[1024], filename3[1024];
+    H5G_info_t  grp_info;
+    herr_t	status;
+
+    TESTING("same file mount operations");
+    h5_fixname(FILENAME[0], fapl, filename1, sizeof filename1);
+    h5_fixname(FILENAME[1], fapl, filename2, sizeof filename2);
+    h5_fixname(FILENAME[2], fapl, filename3, sizeof filename3);
+
+
+    /* Open the files */
+    if((file1a = H5Fopen(filename1, H5F_ACC_RDONLY, fapl)) < 0)
+	FAIL_STACK_ERROR
+    if((file1b = H5Fopen(filename1, H5F_ACC_RDONLY, fapl)) < 0)
+	FAIL_STACK_ERROR
+    if((file2 = H5Fopen(filename2, H5F_ACC_RDONLY, fapl)) < 0)
+	FAIL_STACK_ERROR
+    if((file3 = H5Fopen(filename3, H5F_ACC_RDONLY, fapl)) < 0)
+	FAIL_STACK_ERROR
+
+    /*
+     * Try mounting different files at the same place in each of the "top"
+     *  files.
+     *
+     * We have to open the mount point before we mount the first file or we'll
+     * end up mounting file4 at the root of file3 and the mount will succeed.
+     */
+    if((mnt1a = H5Gopen2(file1a, "/mnt1", H5P_DEFAULT)) < 0) FAIL_STACK_ERROR
+    if(H5Gget_info(mnt1a, &grp_info) < 0) FAIL_STACK_ERROR
+    if(grp_info.mounted) FAIL_PUTS_ERROR("    Group shouldn't have 'mounted' flag set.")
+    if((mnt1b = H5Gopen2(file1b, "/mnt1", H5P_DEFAULT)) < 0) FAIL_STACK_ERROR
+    if(H5Gget_info(mnt1b, &grp_info) < 0) FAIL_STACK_ERROR
+    if(grp_info.mounted) FAIL_PUTS_ERROR("    Group shouldn't have 'mounted' flag set.")
+    if(H5Fmount(mnt1a, ".", file2, H5P_DEFAULT) < 0) FAIL_STACK_ERROR
+    if(H5Gget_info(mnt1a, &grp_info) < 0) FAIL_STACK_ERROR
+    if(!grp_info.mounted) FAIL_PUTS_ERROR("    Group should have 'mounted' flag set.")
+    H5E_BEGIN_TRY {
+	status = H5Fmount(mnt1b, ".", file3, H5P_DEFAULT);
+    } H5E_END_TRY;
+    if(status >= 0) FAIL_PUTS_ERROR("    Mounting different files at one mount point should have failed.")
+    if(H5Funmount(mnt1a, ".") < 0) FAIL_STACK_ERROR
+    if(H5Gclose(mnt1a) < 0) FAIL_STACK_ERROR
+    if(H5Gclose(mnt1b) < 0) FAIL_STACK_ERROR
+
+    /*
+     * Try mounting same files at the same place in each of the "top"
+     *  files.
+     *
+     * We have to open the mount point before we mount the first file or we'll
+     * end up mounting file4 at the root of file3 and the mount will succeed.
+     */
+    if((mnt1a = H5Gopen2(file1a, "/mnt1", H5P_DEFAULT)) < 0) FAIL_STACK_ERROR
+    if(H5Gget_info(mnt1a, &grp_info) < 0) FAIL_STACK_ERROR
+    if(grp_info.mounted) FAIL_PUTS_ERROR("    Group shouldn't have 'mounted' flag set.")
+    if((mnt1b = H5Gopen2(file1b, "/mnt1", H5P_DEFAULT)) < 0) FAIL_STACK_ERROR
+    if(H5Gget_info(mnt1b, &grp_info) < 0) FAIL_STACK_ERROR
+    if(grp_info.mounted) FAIL_PUTS_ERROR("    Group shouldn't have 'mounted' flag set.")
+    if(H5Fmount(mnt1a, ".", file2, H5P_DEFAULT) < 0) FAIL_STACK_ERROR
+    if(H5Gget_info(mnt1a, &grp_info) < 0) FAIL_STACK_ERROR
+    if(!grp_info.mounted) FAIL_PUTS_ERROR("    Group should have 'mounted' flag set.")
+    H5E_BEGIN_TRY {
+	status = H5Fmount(mnt1b, ".", file2, H5P_DEFAULT);
+    } H5E_END_TRY;
+    if(status >= 0) FAIL_PUTS_ERROR("    Mounting same files at one mount point should have failed.")
+    if(H5Funmount(mnt1a, ".") < 0) FAIL_STACK_ERROR
+    if(H5Gclose(mnt1a) < 0) FAIL_STACK_ERROR
+    if(H5Gclose(mnt1b) < 0) FAIL_STACK_ERROR
+
+
+    /* Close everything and return */
+    if(H5Fclose(file1a) < 0) FAIL_STACK_ERROR
+    if(H5Fclose(file1b) < 0) FAIL_STACK_ERROR
+    if(H5Fclose(file2) < 0) FAIL_STACK_ERROR
+    if(H5Fclose(file3) < 0) FAIL_STACK_ERROR
+
+    PASSED();
+    return 0;
+
+error:
+    H5E_BEGIN_TRY {
+	H5Gclose(mnt1a);
+	H5Gclose(mnt1b);
+	H5Fclose(file1a);
+	H5Fclose(file1b);
+	H5Fclose(file2);
+	H5Fclose(file3);
+    } H5E_END_TRY;
+    return 1;
+} /* end test_samefile() */
+
+
+/*-------------------------------------------------------------------------
  * Function:	test_hide
  *
  * Purpose:	The previous contents of the mount point is temporarily
@@ -3817,6 +3951,7 @@ main(void)
 
 	nerrors += test_basic(fapl);
 	nerrors += test_illegal(fapl);
+	nerrors += test_samefile(fapl);
 	nerrors += test_hide(fapl);
 	nerrors += test_assoc(fapl);
 	nerrors += test_mntlnk(fapl);