HDDFV-10361 combine duplicated prefix utility functions

4 files changed, 383 insertions, 579 deletions

diff --git a/src/H5Dvirtual.c b/src/H5Dvirtual.c
index 306fe62..9e1ebe8 100644
--- a/src/H5Dvirtual.c
+++ b/src/H5Dvirtual.c
@@ -147,7 +147,7 @@ H5FL_DEFINE(H5O_storage_virtual_name_seg_t);
 H5FL_DEFINE_STATIC(H5D_virtual_held_file_t);
 
 
-
+
 /*-------------------------------------------------------------------------
  * Function:    H5D_virtual_check_mapping_pre
  *
@@ -217,7 +217,7 @@ done:
     FUNC_LEAVE_NOAPI(ret_value)
 } /* end H5D_virtual_check_mapping_pre() */
 
-
+
 /*-------------------------------------------------------------------------
  * Function:    H5D_virtual_check_mapping_post
  *
@@ -285,7 +285,7 @@ done:
     FUNC_LEAVE_NOAPI(ret_value)
 } /* end H5D_virtual_check_mapping_post() */
 
-
+
 /*-------------------------------------------------------------------------
  * Function:    H5D_virtual_update_min_dims
  *
@@ -344,7 +344,7 @@ done:
     FUNC_LEAVE_NOAPI(ret_value)
 } /* end H5D_virtual_update_min_dims() */
 
-
+
 /*-------------------------------------------------------------------------
  * Function:    H5D_virtual_check_min_dims
  *
@@ -389,7 +389,7 @@ done:
     FUNC_LEAVE_NOAPI(ret_value)
 } /* end H5D_virtual_check_min_dims() */
 
-
+
 /*-------------------------------------------------------------------------
  * Function:    H5D__virtual_copy_layout
  *
@@ -553,7 +553,7 @@ done:
     FUNC_LEAVE_NOAPI(ret_value)
 } /* end H5D__virtual_copy_layout() */
 
-
+
 /*-------------------------------------------------------------------------
  * Function:    H5D__virtual_reset_layout
  *
@@ -637,7 +637,7 @@ H5D__virtual_reset_layout(H5O_layout_t *layout)
     FUNC_LEAVE_NOAPI(ret_value)
 } /* end H5D__virtual_reset_layout() */
 
-
+
 /*-------------------------------------------------------------------------
  * Function:    H5D__virtual_copy
  *
@@ -683,7 +683,7 @@ done:
     FUNC_LEAVE_NOAPI(ret_value)
 } /* end H5D__virtual_copy() */
 
-
+
 /*-------------------------------------------------------------------------
  * Function:    H5D__virtual_delete
  *
@@ -733,255 +733,6 @@ done:
 } /* end H5D__virtual_delete */
 
 
-/*--------------------------------------------------------------------------
- * Function: H5D__virtual_build_name
- *
- * Purpose:  Prepend PREFIX to FILE_NAME and store in FULL_NAME
- *
- * Return:   Non-negative on success/Negative on failure
- *--------------------------------------------------------------------------*/
-static herr_t
-H5D__virtual_build_name(char *prefix, char *file_name, char **full_name/*out*/)
-{
-    size_t      prefix_len;             /* length of prefix */
-    size_t      fname_len;              /* Length of external link file name */
-    herr_t      ret_value = SUCCEED;    /* Return value */
-
-    FUNC_ENTER_NOAPI_NOINIT
-
-    prefix_len = HDstrlen(prefix);
-    fname_len = HDstrlen(file_name);
-
-    /* Allocate a buffer to hold the filename + prefix + possibly the delimiter + terminating null byte */
-    if(NULL == (*full_name = (char *)H5MM_malloc(prefix_len + fname_len + 2)))
-        HGOTO_ERROR(H5E_RESOURCE, H5E_NOSPACE, FAIL, "unable to allocate filename buffer")
-
-    /* Compose the full file name */
-    HDsnprintf(*full_name, (prefix_len + fname_len + 2), "%s%s%s", prefix,
-        (H5_CHECK_DELIMITER(prefix[prefix_len - 1]) ? "" : H5_DIR_SEPS), file_name);
-
-done:
-    FUNC_LEAVE_NOAPI(ret_value)
-} /* H5D__virtual_build_name() */
-
-
-/*--------------------------------------------------------------------------
- * Function: H5D_getenv_prefix_name --
- *
- * Purpose:  Get the first pathname in the list of pathnames stored in env_prefix,
- *           which is separated by the environment delimiter.
- *           env_prefix is modified to point to the remaining pathnames
- *           in the list.
- *
- * Return:   A pointer to a pathname
---------------------------------------------------------------------------*/
-static char *
-H5D_getenv_prefix_name(char **env_prefix/*in,out*/)
-{
-    char        *retptr=NULL;
-    char        *strret=NULL;
-
-    FUNC_ENTER_NOAPI_NOINIT_NOERR
-
-    strret = HDstrchr(*env_prefix, H5_COLON_SEPC);
-    if (strret == NULL) {
-        retptr = *env_prefix;
-        *env_prefix = strret;
-    } else {
-        retptr = *env_prefix;
-        *env_prefix = strret + 1;
-        *strret = '\0';
-    }
-
-    FUNC_LEAVE_NOAPI(retptr)
-} /* end H5D_getenv_prefix_name() */
-
-/*-------------------------------------------------------------------------
- * Function:    H5D__virtual_open_file
- *
- * Purpose:     Attempts to open a source dataset file.
- *
- * Return:      Non-negative on success/Negative on failure
- *-------------------------------------------------------------------------
- */
-static H5F_t *
-H5D__virtual_open_file(hid_t plist_id, const H5F_t *vdset_file,
-        const char *file_name,
-        hid_t fapl_id, hid_t dxpl_id)
-{
-    H5F_t       *src_file = NULL;       /* Source file */
-    H5F_t       *ret_value = NULL;      /* Actual return value  */
-    char        *full_name = NULL;      /* File name with prefix */
-    char        *my_prefix = NULL;      /* Library's copy of the prefix */
-    unsigned    intent;                 /* File access permissions */
-    char        *actual_file_name = NULL; /* Virtual file's actual name */
-    char        *temp_file_name = NULL; /* Temporary pointer to file name */
-    size_t      temp_file_name_len;     /* Length of temporary file name */
-
-    FUNC_ENTER_STATIC
-
-    /* Simplify intent flags for open calls */
-    intent = H5F_INTENT(vdset_file);
-    intent &= (H5F_ACC_RDWR | H5F_ACC_SWMR_WRITE | H5F_ACC_SWMR_READ);
-
-    /* Copy the file name to use */
-    if(NULL == (temp_file_name = H5MM_strdup(file_name)))
-        HGOTO_ERROR(H5E_RESOURCE, H5E_NOSPACE, NULL, "memory allocation failed")
-    temp_file_name_len = HDstrlen(temp_file_name);
-
-    /* target file_name is an absolute pathname: see RM for detailed description */
-    if(H5_CHECK_ABSOLUTE(file_name) || H5_CHECK_ABS_PATH(file_name)) {
-        /* Try opening file */
-        if(NULL == (src_file = H5F_open(file_name, intent, H5P_FILE_CREATE_DEFAULT, fapl_id, dxpl_id))) {
-            char *ptr;
-
-            H5E_clear_stack(NULL);
-
-            /* get last component of file_name */
-            H5_GET_LAST_DELIMITER(file_name, ptr)
-            HDassert(ptr);
-
-            /* Increment past delimiter */
-            ptr++;
-
-            /* Copy into the temp. file name */
-            HDstrncpy(temp_file_name, ptr, temp_file_name_len);
-            temp_file_name[temp_file_name_len - 1] = '\0';
-        } /* end if */
-    } /* end if */
-    else if(H5_CHECK_ABS_DRIVE(file_name)) {
-        /* Try opening file */
-        if(NULL == (src_file = H5F_open(file_name, intent, H5P_FILE_CREATE_DEFAULT, fapl_id, dxpl_id))) {
-
-            H5E_clear_stack(NULL);
-
-            /* strip "<drive-letter>:" */
-            HDstrncpy(temp_file_name, &file_name[2], temp_file_name_len);
-            temp_file_name[temp_file_name_len - 1] = '\0';
-        } /* end if */
-    } /* end if */
-
-    /* try searching from paths set in the environment variable */
-    if(src_file == NULL) {
-        char *env_prefix;
-
-        if(NULL != (env_prefix = HDgetenv("HDF5_VDS_PREFIX"))) {
-            char *tmp_env_prefix, *saved_env;
-
-            if(NULL == (saved_env = tmp_env_prefix = H5MM_strdup(env_prefix)))
-                HGOTO_ERROR(H5E_RESOURCE, H5E_NOSPACE, NULL, "memory allocation failed")
-
-            while((tmp_env_prefix) && (*tmp_env_prefix)) {
-                char *out_prefix_name;
-
-                out_prefix_name = H5D_getenv_prefix_name(&tmp_env_prefix/*in,out*/);
-                if(out_prefix_name && (*out_prefix_name)) {
-                    if(H5D__virtual_build_name(out_prefix_name, temp_file_name, &full_name/*out*/) < 0) {
-                        saved_env = (char *)H5MM_xfree(saved_env);
-                        HGOTO_ERROR(H5E_DATASET, H5E_CANTGET, NULL, "can't prepend prefix to filename")
-                    } /* end if */
-
-                    src_file = H5F_open(full_name, intent, H5P_FILE_CREATE_DEFAULT, fapl_id, dxpl_id);
-                    full_name = (char *)H5MM_xfree(full_name);
-                    if(src_file != NULL)
-                        break;
-                    H5E_clear_stack(NULL);
-                } /* end if */
-            } /* end while */
-            saved_env = (char *)H5MM_xfree(saved_env);
-        } /* end if */
-    } /* end if */
-
-    /* try searching from property list */
-    if(src_file == NULL) {
-        size_t  size = 0;
-        H5E_BEGIN_TRY {
-            size = H5Pget_virtual_prefix(plist_id, NULL, 0);
-        } H5E_END_TRY;
-        if(size <= 0)
-            my_prefix = NULL;
-        else {
-            /* Allocate a buffer to hold the filename + prefix + possibly the delimiter + terminating null byte */
-            if(NULL == (my_prefix = (char *)H5MM_malloc(size + 1)))
-                HGOTO_ERROR(H5E_RESOURCE, H5E_NOSPACE, NULL, "unable to allocate prefix buffer")
-            if(H5Pget_virtual_prefix(plist_id, my_prefix, size+1) < 0)
-                HGOTO_ERROR(H5E_PLIST, H5E_CANTGET, NULL, "can't get vds  prefix")
-            if(my_prefix) {
-                if(H5D__virtual_build_name(my_prefix, temp_file_name, &full_name/*out*/) < 0)
-                    HGOTO_ERROR(H5E_DATASET, H5E_CANTGET, NULL, "can't prepend prefix to filename")
-                my_prefix = (char *)H5MM_xfree(my_prefix);
-                if(NULL == (src_file = H5F_open(full_name, intent, H5P_FILE_CREATE_DEFAULT, fapl_id, dxpl_id)))
-                    H5E_clear_stack(NULL);
-                full_name = (char *)H5MM_xfree(full_name);
-            }
-        } /* end if */
-    } /* end if */
-
-    /* try searching from main file's "extpath": see description in H5F_open() & H5_build_extpath() */
-    if(src_file == NULL) {
-        char *vdspath;
-
-        if(NULL != (vdspath = H5F_EXTPATH(vdset_file))) {
-            if(H5D__virtual_build_name(vdspath, temp_file_name, &full_name/*out*/) < 0)
-                HGOTO_ERROR(H5E_DATASET, H5E_CANTGET, NULL, "can't prepend prefix to filename")
-            if(NULL == (src_file = H5F_open(full_name, intent, H5P_FILE_CREATE_DEFAULT, fapl_id, dxpl_id)))
-                H5E_clear_stack(NULL);
-            full_name = (char *)H5MM_xfree(full_name);
-        } /* end if */
-    } /* end if */
-
-    /* try the relative file_name stored in temp_file_name */
-    if(src_file == NULL) {
-        if(NULL == (src_file = H5F_open(temp_file_name, intent, H5P_FILE_CREATE_DEFAULT, fapl_id, dxpl_id)))
-            H5E_clear_stack(NULL);
-    } /* end if */
-
-    /* try the 'resolved' name for the virtual file */
-    if(src_file == NULL) {
-        char *ptr = NULL;
-
-        /* Copy resolved file name */
-        if(NULL == (actual_file_name = H5MM_strdup(H5F_ACTUAL_NAME(vdset_file))))
-            HGOTO_ERROR(H5E_DATASET, H5E_CANTALLOC, NULL, "can't duplicate resolved file name string")
-
-        /* get last component of file_name */
-        H5_GET_LAST_DELIMITER(actual_file_name, ptr)
-        if(!ptr)
-            HGOTO_ERROR(H5E_DATASET, H5E_CANTOPENFILE, NULL, "unable to open vds file, vds file name = '%s', temp_file_name = '%s'", file_name, temp_file_name)
-
-        /* Truncate filename portion from actual file name path */
-        *ptr = '\0';
-
-        /* Build new file name for the external file */
-        if(H5D__virtual_build_name(actual_file_name, temp_file_name, &full_name/*out*/) < 0)
-            HGOTO_ERROR(H5E_DATASET, H5E_CANTGET, NULL, "can't prepend prefix to filename")
-        actual_file_name = (char *)H5MM_xfree(actual_file_name);
-
-        /* Try opening with the resolved name */
-        if(NULL == (src_file = H5F_open(full_name, intent, H5P_FILE_CREATE_DEFAULT, fapl_id, dxpl_id)))
-            HGOTO_ERROR(H5E_DATASET, H5E_CANTOPENFILE, NULL, "unable to open vds file, vds file name = '%s', temp_file_name = '%s'", file_name, temp_file_name)
-        full_name = (char *)H5MM_xfree(full_name);
-    } /* end if */
-
-    /* Success */
-    ret_value = src_file;
-done:
-    if((NULL == ret_value) && src_file)
-        if(H5F_try_close(src_file, NULL) < 0)
-            HDONE_ERROR(H5E_DATASET, H5E_CANTCLOSEFILE, NULL, "can't close source file")
-    if(my_prefix)
-        my_prefix = (char *)H5MM_xfree(my_prefix);
-    if(full_name)
-        full_name = (char *)H5MM_xfree(full_name);
-    if(temp_file_name)
-        temp_file_name = (char *)H5MM_xfree(temp_file_name);
-    if(actual_file_name)
-        actual_file_name = (char *)H5MM_xfree(actual_file_name);
-
-    FUNC_LEAVE_NOAPI(ret_value)
-} /* H5D__virtual_open_file() */
-
-
 /*-------------------------------------------------------------------------
  * Function:    H5D__virtual_open_source_dset
  *
@@ -1000,13 +751,11 @@ H5D__virtual_open_source_dset(const H5D_t *vdset,
     H5O_storage_virtual_srcdset_t *source_dset, hid_t dxpl_id)
 {
     H5F_t       *src_file = NULL;       /* Source file */
-    char        *vds_prefix = NULL;     /* Source file vds_prefix */
     hbool_t     src_file_open = FALSE;  /* Whether we have opened and need to close src_file */
     H5G_loc_t   src_root_loc;           /* Object location of source file root group */
     herr_t      ret_value = SUCCEED;    /* Return value */
-    char        *full_name = NULL;      /* File name with prefix */
-    unsigned    intent;                 /* File access permissions */
     hid_t       plist_id = -1;          /* Property list pointer */
+    unsigned    intent;                 /* File access permissions */
 
     FUNC_ENTER_STATIC
 
@@ -1019,9 +768,11 @@ H5D__virtual_open_source_dset(const H5D_t *vdset,
 
     /* Check if we need to open the source file */
     if(HDstrcmp(source_dset->file_name, ".")) {
-        if((plist_id = H5D_get_access_plist(vdset)) < 0)
+        if((plist_id = H5D_get_access_plist((H5D_t *)vdset)) < 0)
             HGOTO_ERROR(H5E_DATASET, H5E_CANTGET, FAIL, "Can't get access plist")
-        if(NULL == (src_file = H5D__virtual_open_file(plist_id, vdset->oloc.file, source_dset->file_name, vdset->shared->layout.storage.u.virt.source_fapl, dxpl_id)))
+        intent = H5F_INTENT(vdset->oloc.file);
+        if(NULL == (src_file = H5F_prefix_open_file(plist_id, vdset->oloc.file, H5D_ACS_VDS_PREFIX_NAME, source_dset->file_name, intent,
+                vdset->shared->layout.storage.u.virt.source_fapl, dxpl_id)))
             H5E_clear_stack(NULL); /* Quick hack until proper support for H5Fopen with missing file is implemented */
         else
             src_file_open = TRUE;
@@ -1062,13 +813,13 @@ done:
         H5Pclose(plist_id);
     /* Close source file */
     if(src_file_open)
-        if(H5F_try_close(src_file, NULL) < 0)
+        if(H5F_efc_close(vdset->oloc.file, src_file) < 0)
             HDONE_ERROR(H5E_DATASET, H5E_CANTCLOSEFILE, FAIL, "can't close source file")
 
     FUNC_LEAVE_NOAPI(ret_value)
 } /* end H5D__virtual_open_source_dset() */
 
-
+
 /*-------------------------------------------------------------------------
  * Function:    H5D__virtual_reset_source_dset
  *
@@ -1155,7 +906,7 @@ H5D__virtual_reset_source_dset(H5O_storage_virtual_ent_t *virtual_ent,
     FUNC_LEAVE_NOAPI(ret_value)
 } /* end H5D__virtual_reset_source_dset() */
 
-
+
 /*-------------------------------------------------------------------------
  * Function:    H5D__virtual_str_append
  *
@@ -1231,7 +982,7 @@ done:
     FUNC_LEAVE_NOAPI(ret_value);
 } /* end H5D__virtual_str_append() */
 
-
+
 /*-------------------------------------------------------------------------
  * Function:    H5D_virtual_parse_source_name
  *
@@ -1347,7 +1098,7 @@ done:
     FUNC_LEAVE_NOAPI(ret_value)
 } /* end H5D_virtual_parse_source_name() */
 
-
+
 /*-------------------------------------------------------------------------
  * Function:    H5D__virtual_copy_parsed_name
  *
@@ -1404,7 +1155,7 @@ done:
     FUNC_LEAVE_NOAPI(ret_value)
 } /* end H5D__virtual_copy_parsed_name() */
 
-
+
 /*-------------------------------------------------------------------------
  * Function:    H5D_virtual_free_parsed_name
  *
@@ -1437,7 +1188,7 @@ done:
     FUNC_LEAVE_NOAPI(ret_value)
 } /* end H5D_virtual_free_parsed_name() */
 
-
+
 /*-------------------------------------------------------------------------
  * Function:    H5D__virtual_build_source_name
  *
@@ -1539,7 +1290,7 @@ done:
     FUNC_LEAVE_NOAPI(ret_value)
 } /* end H5D__virtual_build_source_name() */
 
-
+
 /*-------------------------------------------------------------------------
  * Function:    H5D__virtual_set_extent_unlim
  *
@@ -1967,7 +1718,7 @@ done:
     FUNC_LEAVE_NOAPI(ret_value)
 } /* end H5D__virtual_set_extent_unlim() */
 
-
+
 /*-------------------------------------------------------------------------
  * Function:    H5D__virtual_init_all
  *
@@ -2191,7 +1942,7 @@ done:
     FUNC_LEAVE_NOAPI(ret_value)
 } /* end H5D__virtual_init_all() */
 
-
+
 /*-------------------------------------------------------------------------
  * Function:    H5D__virtual_init
  *
@@ -2286,7 +2037,7 @@ done:
     FUNC_LEAVE_NOAPI(ret_value)
 } /* end H5D__virtual_init() */
 
-
+
 /*-------------------------------------------------------------------------
  * Function:    H5D__virtual_is_space_alloc
  *
@@ -2318,7 +2069,7 @@ H5D__virtual_is_space_alloc(const H5O_storage_t H5_ATTR_UNUSED *storage)
     FUNC_LEAVE_NOAPI(ret_value)
 } /* end H5D__virtual_is_space_alloc() */
 
-
+
 /*-------------------------------------------------------------------------
  * Function:    H5D__virtual_pre_io
  *
@@ -2559,7 +2310,7 @@ done:
     FUNC_LEAVE_NOAPI(ret_value)
 } /* end H5D__virtual_pre_io() */
 
-
+
 /*-------------------------------------------------------------------------
  * Function:    H5D__virtual_post_io
  *
@@ -2609,7 +2360,7 @@ H5D__virtual_post_io(H5O_storage_virtual_t *storage)
     FUNC_LEAVE_NOAPI(ret_value)
 } /* end H5D__virtual_post_io() */
 
-
+
 /*-------------------------------------------------------------------------
  * Function:    H5D__virtual_read_one
  *
@@ -2666,7 +2417,7 @@ done:
     FUNC_LEAVE_NOAPI(ret_value)
 } /* end H5D__virtual_read_one() */
 
-
+
 /*-------------------------------------------------------------------------
  * Function:    H5D__virtual_read
  *
@@ -2799,7 +2550,7 @@ done:
     FUNC_LEAVE_NOAPI(ret_value)
 } /* end H5D__virtual_read() */
 
-
+
 /*-------------------------------------------------------------------------
  * Function:    H5D__virtual_write_one
  *
@@ -2858,7 +2609,7 @@ done:
     FUNC_LEAVE_NOAPI(ret_value)
 } /* end H5D__virtual_write_one() */
 
-
+
 /*-------------------------------------------------------------------------
  * Function:    H5D__virtual_write
  *
@@ -2935,7 +2686,7 @@ done:
     FUNC_LEAVE_NOAPI(ret_value)
 } /* end H5D__virtual_write() */
 
-
+
 /*-------------------------------------------------------------------------
  * Function:    H5D__virtual_flush
  *
@@ -2983,7 +2734,7 @@ done:
     FUNC_LEAVE_NOAPI(ret_value)
 } /* end H5D__virtual_flush() */
 
-
+
 /*-------------------------------------------------------------------------
  * Function:    H5D__virtual_hold_source_dset_files
  *
@@ -3061,7 +2812,7 @@ done:
     FUNC_LEAVE_NOAPI(ret_value)
 } /* end H5D__virtual_hold_source_dset_files() */
 
-
+
 /*-------------------------------------------------------------------------
  * Function:    H5D__virtual_refresh_source_dset
  *
@@ -3101,7 +2852,7 @@ done:
     FUNC_LEAVE_NOAPI(ret_value)
 } /* end H5D__virtual_refresh_source_dsets() */
 
-
+
 /*-------------------------------------------------------------------------
  * Function:    H5D__virtual_refresh_source_dsets
  *
@@ -3154,7 +2905,7 @@ done:
     FUNC_LEAVE_NOAPI(ret_value)
 } /* end H5D__virtual_refresh_source_dsets() */
 
-
+
 /*-------------------------------------------------------------------------
  * Function:    H5D__virtual_release_source_dset_files
  *
diff --git a/src/H5Fint.c b/src/H5Fint.c
index 8212eb5..b135ce1 100644
--- a/src/H5Fint.c
+++ b/src/H5Fint.c
@@ -30,6 +30,7 @@
 #include "H5FDprivate.h"       /* File drivers */
 #include "H5Gprivate.h"        /* Groups */
 #include "H5Iprivate.h"        /* IDs */
+#include "H5Lprivate.h"        /* Links */
 #include "H5MFprivate.h"       /* File memory management */
 #include "H5MMprivate.h"       /* Memory management */
 #include "H5Pprivate.h"        /* Property lists */
@@ -98,7 +99,7 @@ H5FL_DEFINE(H5F_t);
 /* Declare a free list to manage the H5F_file_t struct */
 H5FL_DEFINE(H5F_file_t);
 
-
+
 /*-------------------------------------------------------------------------
  * Function: H5F_get_access_plist
  *
@@ -213,7 +214,7 @@ done:
     FUNC_LEAVE_NOAPI(ret_value)
 } /* end H5F_get_access_plist() */
 
-
+
 /*-------------------------------------------------------------------------
  * Function: H5F_get_obj_count
  *
@@ -241,7 +242,7 @@ done:
     FUNC_LEAVE_NOAPI(ret_value)
 } /* end H5F_get_obj_count() */
 
-
+
 /*-------------------------------------------------------------------------
  * Function:    H5F_get_obj_ids
  *
@@ -268,7 +269,7 @@ done:
     FUNC_LEAVE_NOAPI(ret_value)
 } /* end H5F_get_obj_ids() */
 
-
+
 /*---------------------------------------------------------------------------
  * Function: H5F_get_objects
  *
@@ -370,7 +371,7 @@ done:
     FUNC_LEAVE_NOAPI(ret_value)
 } /* end H5F_get_objects() */
 
-
+
 /*-------------------------------------------------------------------------
  * Function: H5F_get_objects_cb
  *
@@ -479,7 +480,265 @@ done:
     FUNC_LEAVE_NOAPI(ret_value)
 } /* end H5F_get_objects_cb() */
 
-
+/*--------------------------------------------------------------------------
+ * Function: H5F_build_name
+ *
+ * Purpose:  Prepend PREFIX to FILE_NAME and store in FULL_NAME
+ *
+ * Return:   Non-negative on success/Negative on failure
+ *--------------------------------------------------------------------------*/
+herr_t
+H5F_build_name(char *prefix, char *file_name, char **full_name/*out*/)
+{
+    size_t      prefix_len;             /* length of prefix */
+    size_t      fname_len;              /* Length of external link file name */
+    herr_t      ret_value = SUCCEED;    /* Return value */
+
+    FUNC_ENTER_NOAPI_NOINIT
+
+    prefix_len = HDstrlen(prefix);
+    fname_len = HDstrlen(file_name);
+
+    /* Allocate a buffer to hold the filename + prefix + possibly the delimiter + terminating null byte */
+    if(NULL == (*full_name = (char *)H5MM_malloc(prefix_len + fname_len + 2)))
+        HGOTO_ERROR(H5E_RESOURCE, H5E_NOSPACE, FAIL, "unable to allocate filename buffer")
+
+    /* Compose the full file name */
+    HDsnprintf(*full_name, (prefix_len + fname_len + 2), "%s%s%s", prefix,
+        (H5_CHECK_DELIMITER(prefix[prefix_len - 1]) ? "" : H5_DIR_SEPS), file_name);
+
+done:
+    FUNC_LEAVE_NOAPI(ret_value)
+} /* H5F_build_name() */
+
+
+/*--------------------------------------------------------------------------
+ * Function: H5F_getenv_prefix_name --
+ *
+ * Purpose:  Get the first pathname in the list of pathnames stored in env_prefix,
+ *           which is separated by the environment delimiter.
+ *           env_prefix is modified to point to the remaining pathnames
+ *           in the list.
+ *
+ * Return:   A pointer to a pathname
+--------------------------------------------------------------------------*/
+char *
+H5F_getenv_prefix_name(char **env_prefix/*in,out*/)
+{
+    char        *retptr=NULL;
+    char        *strret=NULL;
+
+    FUNC_ENTER_NOAPI_NOINIT_NOERR
+
+    strret = HDstrchr(*env_prefix, H5_COLON_SEPC);
+    if (strret == NULL) {
+        retptr = *env_prefix;
+        *env_prefix = strret;
+    } else {
+        retptr = *env_prefix;
+        *env_prefix = strret + 1;
+        *strret = '\0';
+    }
+
+    FUNC_LEAVE_NOAPI(retptr)
+} /* end H5F_getenv_prefix_name() */
+
+/*-------------------------------------------------------------------------
+ * Function:    H5F_prefix_open_file
+ *
+ * Purpose:     Attempts to open a dataset file.
+ *
+ * Return:      Non-negative on success/Negative on failure
+ *-------------------------------------------------------------------------
+ */
+H5F_t *
+H5F_prefix_open_file(hid_t plist_id, H5F_t *primary_file, const char *prefix_type,
+        const char *file_name, unsigned file_intent, hid_t fapl_id, hid_t dxpl_id)
+{
+    H5F_t       *src_file = NULL;       /* Source file */
+    H5F_t       *ret_value = NULL;      /* Actual return value  */
+    char        *full_name = NULL;      /* File name with prefix */
+    char        *my_prefix = NULL;      /* Library's copy of the prefix */
+    char        *actual_file_name = NULL; /* File's actual name */
+    char        *temp_file_name = NULL; /* Temporary pointer to file name */
+    size_t      temp_file_name_len;     /* Length of temporary file name */
+
+    FUNC_ENTER_STATIC
+
+    /* Simplify intent flags for open calls */
+    file_intent &= (H5F_ACC_RDWR | H5F_ACC_SWMR_WRITE | H5F_ACC_SWMR_READ);
+
+    /* Copy the file name to use */
+    if(NULL == (temp_file_name = H5MM_strdup(file_name)))
+        HGOTO_ERROR(H5E_RESOURCE, H5E_NOSPACE, NULL, "memory allocation failed")
+    temp_file_name_len = HDstrlen(temp_file_name);
+
+    /* target file_name is an absolute pathname: see RM for detailed description */
+    if(H5_CHECK_ABSOLUTE(file_name) || H5_CHECK_ABS_PATH(file_name)) {
+        /* Try opening file */
+        if(NULL == (src_file = H5F_efc_open(primary_file, file_name, file_intent, H5P_FILE_CREATE_DEFAULT, fapl_id, dxpl_id))) {
+            char *ptr;
+
+            H5E_clear_stack(NULL);
+
+            /* get last component of file_name */
+            H5_GET_LAST_DELIMITER(file_name, ptr)
+            HDassert(ptr);
+
+            /* Increment past delimiter */
+            ptr++;
+
+            /* Copy into the temp. file name */
+            HDstrncpy(temp_file_name, ptr, temp_file_name_len);
+            temp_file_name[temp_file_name_len - 1] = '\0';
+        } /* end if */
+    } /* end if */
+    else if(H5_CHECK_ABS_DRIVE(file_name)) {
+        /* Try opening file */
+        if(NULL == (src_file = H5F_efc_open(primary_file, file_name, file_intent, H5P_FILE_CREATE_DEFAULT, fapl_id, dxpl_id))) {
+
+            H5E_clear_stack(NULL);
+
+            /* strip "<drive-letter>:" */
+            HDstrncpy(temp_file_name, &file_name[2], temp_file_name_len);
+            temp_file_name[temp_file_name_len - 1] = '\0';
+        } /* end if */
+    } /* end if */
+
+    /* try searching from paths set in the environment variable */
+    if(src_file == NULL) {
+        char *env_prefix;
+
+        if (HDstrcmp(prefix_type, H5D_ACS_VDS_PREFIX_NAME) == 0)
+            env_prefix = HDgetenv("HDF5_VDS_PREFIX");
+        else if (HDstrcmp(prefix_type, H5L_ACS_ELINK_PREFIX_NAME) == 0)
+            env_prefix = HDgetenv("HDF5_EXT_PREFIX");
+        else
+            HGOTO_ERROR(H5E_PLIST, H5E_BADTYPE, NULL, "prefix name is not sensible")
+        if(NULL != env_prefix) {
+            char *tmp_env_prefix, *saved_env;
+
+            if(NULL == (saved_env = tmp_env_prefix = H5MM_strdup(env_prefix)))
+                HGOTO_ERROR(H5E_RESOURCE, H5E_NOSPACE, NULL, "memory allocation failed")
+
+            while((tmp_env_prefix) && (*tmp_env_prefix)) {
+                char *out_prefix_name;
+
+                out_prefix_name = H5F_getenv_prefix_name(&tmp_env_prefix/*in,out*/);
+                if(out_prefix_name && (*out_prefix_name)) {
+                    if(H5F_build_name(out_prefix_name, temp_file_name, &full_name/*out*/) < 0) {
+                        saved_env = (char *)H5MM_xfree(saved_env);
+                        HGOTO_ERROR(H5E_FILE, H5E_CANTGET, NULL, "can't prepend prefix to filename")
+                    } /* end if */
+
+                    src_file = H5F_efc_open(primary_file, full_name, file_intent, H5P_FILE_CREATE_DEFAULT, fapl_id, dxpl_id);
+                    full_name = (char *)H5MM_xfree(full_name);
+                    if(src_file != NULL)
+                        break;
+                    H5E_clear_stack(NULL);
+                } /* end if */
+            } /* end while */
+            saved_env = (char *)H5MM_xfree(saved_env);
+        } /* end if */
+    } /* end if */
+
+    /* try searching from property list */
+    if(src_file == NULL) {
+        ssize_t  size = 0;
+        H5E_BEGIN_TRY {
+            if (HDstrcmp(prefix_type, H5D_ACS_VDS_PREFIX_NAME) == 0)
+                size = H5Pget_virtual_prefix(plist_id, NULL, 0);
+            else if (HDstrcmp(prefix_type, H5L_ACS_ELINK_PREFIX_NAME) == 0)
+                size = H5Pget_elink_prefix(plist_id, NULL, 0);
+        } H5E_END_TRY;
+        if(size <= 0)
+            my_prefix = NULL;
+        else {
+            /* Allocate a buffer to hold the filename + prefix + possibly the delimiter + terminating null byte */
+            if(NULL == (my_prefix = (char *)H5MM_malloc((size_t)size + 1)))
+                HGOTO_ERROR(H5E_RESOURCE, H5E_NOSPACE, NULL, "unable to allocate prefix buffer")
+            if (HDstrcmp(prefix_type, H5D_ACS_VDS_PREFIX_NAME) == 0)
+                size = H5Pget_virtual_prefix(plist_id, my_prefix, (size_t)size+1);
+            else if (HDstrcmp(prefix_type, H5L_ACS_ELINK_PREFIX_NAME) == 0)
+                size = H5Pget_elink_prefix(plist_id, my_prefix, (size_t)size+1);
+            if(size < 0)
+                HGOTO_ERROR(H5E_PLIST, H5E_CANTGET, NULL, "can't get file prefix")
+            if(my_prefix) {
+                if(H5F_build_name(my_prefix, temp_file_name, &full_name/*out*/) < 0)
+                    HGOTO_ERROR(H5E_FILE, H5E_CANTGET, NULL, "can't prepend prefix to filename")
+                my_prefix = (char *)H5MM_xfree(my_prefix);
+                if(NULL == (src_file = H5F_efc_open(primary_file, full_name, file_intent, H5P_FILE_CREATE_DEFAULT, fapl_id, dxpl_id)))
+                    H5E_clear_stack(NULL);
+                full_name = (char *)H5MM_xfree(full_name);
+            }
+        }
+    }
+
+    /* try searching from main file's "extpath": see description in H5F_open() & H5_build_extpath() */
+    if(src_file == NULL) {
+        char *dspath;
+
+        if(NULL != (dspath = H5F_EXTPATH(primary_file))) {
+            if(H5F_build_name(dspath, temp_file_name, &full_name/*out*/) < 0)
+                HGOTO_ERROR(H5E_FILE, H5E_CANTGET, NULL, "can't prepend prefix to filename")
+            if(NULL == (src_file = H5F_efc_open(primary_file, full_name, file_intent, H5P_FILE_CREATE_DEFAULT, fapl_id, dxpl_id)))
+                H5E_clear_stack(NULL);
+            full_name = (char *)H5MM_xfree(full_name);
+        } /* end if */
+    } /* end if */
+
+    /* try the relative file_name stored in temp_file_name */
+    if(src_file == NULL) {
+        if(NULL == (src_file = H5F_efc_open(primary_file, temp_file_name, file_intent, H5P_FILE_CREATE_DEFAULT, fapl_id, dxpl_id)))
+            H5E_clear_stack(NULL);
+    } /* end if */
+
+    /* try the 'resolved' name for the virtual file */
+    if(src_file == NULL) {
+        char *ptr = NULL;
+
+        /* Copy resolved file name */
+        if(NULL == (actual_file_name = H5MM_strdup(H5F_ACTUAL_NAME(primary_file))))
+            HGOTO_ERROR(H5E_FILE, H5E_CANTALLOC, NULL, "can't duplicate resolved file name string")
+
+        /* get last component of file_name */
+        H5_GET_LAST_DELIMITER(actual_file_name, ptr)
+        if(!ptr)
+            HGOTO_ERROR(H5E_FILE, H5E_CANTOPENFILE, NULL, "unable to open file, file name = '%s', temp_file_name = '%s'", file_name, temp_file_name)
+
+        /* Truncate filename portion from actual file name path */
+        *ptr = '\0';
+
+        /* Build new file name for the external file */
+        if(H5F_build_name(actual_file_name, temp_file_name, &full_name/*out*/) < 0)
+            HGOTO_ERROR(H5E_FILE, H5E_CANTGET, NULL, "can't prepend prefix to filename")
+        actual_file_name = (char *)H5MM_xfree(actual_file_name);
+
+        /* Try opening with the resolved name */
+        if(NULL == (src_file = H5F_efc_open(primary_file, full_name, file_intent, H5P_FILE_CREATE_DEFAULT, fapl_id, dxpl_id)))
+            HGOTO_ERROR(H5E_FILE, H5E_CANTOPENFILE, NULL, "unable to open file, file name = '%s', temp_file_name = '%s'", file_name, temp_file_name)
+        full_name = (char *)H5MM_xfree(full_name);
+    } /* end if */
+
+    /* Success */
+    ret_value = src_file;
+done:
+    if((NULL == ret_value) && src_file)
+        if(H5F_efc_close(primary_file, src_file) < 0)
+            HDONE_ERROR(H5E_FILE, H5E_CANTCLOSEFILE, NULL, "can't close source file")
+    if(my_prefix)
+        my_prefix = (char *)H5MM_xfree(my_prefix);
+    if(full_name)
+        full_name = (char *)H5MM_xfree(full_name);
+    if(temp_file_name)
+        temp_file_name = (char *)H5MM_xfree(temp_file_name);
+    if(actual_file_name)
+        actual_file_name = (char *)H5MM_xfree(actual_file_name);
+
+    FUNC_LEAVE_NOAPI(ret_value)
+} /* H5F_prefix_open_file() */
+
+
 /*-------------------------------------------------------------------------
  * Function: H5F__is_hdf5
  *
@@ -528,7 +787,7 @@ done:
     FUNC_LEAVE_NOAPI(ret_value)
 } /* end H5F__is_hdf5() */
 
-
+
 /*-------------------------------------------------------------------------
  * Function: H5F_new
  *
@@ -792,7 +1051,7 @@ done:
     FUNC_LEAVE_NOAPI(ret_value)
 } /* end H5F_new() */
 
-
+
 /*-------------------------------------------------------------------------
  * Function: H5F__dest
  *
@@ -1051,7 +1310,7 @@ H5F__dest(H5F_t *f, hid_t meta_dxpl_id, hid_t raw_dxpl_id, hbool_t flush)
     FUNC_LEAVE_NOAPI(ret_value)
 } /* end H5F_dest() */
 
-
+
 /*-------------------------------------------------------------------------
  * Function:    H5F_open
  *
@@ -1469,7 +1728,7 @@ done:
     FUNC_LEAVE_NOAPI(ret_value)
 } /* end H5F_open() */
 
-
+
 /*-------------------------------------------------------------------------
  * Function: H5F_flush_phase1
  *
@@ -1506,7 +1765,7 @@ H5F__flush_phase1(H5F_t *f, hid_t meta_dxpl_id)
     FUNC_LEAVE_NOAPI(ret_value)
 } /* end H5F__flush_phase1() */
 
-
+
 /*-------------------------------------------------------------------------
  * Function: H5F__flush_phase2
  *
@@ -1568,7 +1827,7 @@ H5F__flush_phase2(H5F_t *f, hid_t meta_dxpl_id, hid_t raw_dxpl_id, hbool_t closi
     FUNC_LEAVE_NOAPI(ret_value)
 } /* end H5F__flush_phase2() */
 
-
+
 /*-------------------------------------------------------------------------
  * Function: H5F__flush
  *
@@ -1600,7 +1859,7 @@ H5F__flush(H5F_t *f, hid_t meta_dxpl_id, hid_t raw_dxpl_id, hbool_t closing)
     FUNC_LEAVE_NOAPI(ret_value)
 } /* end H5F__flush() */
 
-
+
 /*-------------------------------------------------------------------------
  * Function:    H5F_close
  *
@@ -1661,7 +1920,7 @@ done:
     FUNC_LEAVE_NOAPI(ret_value)
 } /* end H5F_close() */
 
-
+
 /*-------------------------------------------------------------------------
  * Function: H5F_try_close
  *
@@ -1834,7 +2093,7 @@ done:
     FUNC_LEAVE_NOAPI(ret_value)
 } /* end H5F_try_close() */
 
-
+
 /*-------------------------------------------------------------------------
  * Function: H5F_get_id
  *
@@ -1870,7 +2129,7 @@ done:
     FUNC_LEAVE_NOAPI(ret_value)
 } /* end H5F_get_id() */
 
-
+
 /*-------------------------------------------------------------------------
  * Function: H5F_incr_nopen_objs
  *
@@ -1891,7 +2150,7 @@ H5F_incr_nopen_objs(H5F_t *f)
     FUNC_LEAVE_NOAPI(++f->nopen_objs)
 } /* end H5F_incr_nopen_objs() */
 
-
+
 /*-------------------------------------------------------------------------
  * Function: H5F_decr_nopen_objs
  *
@@ -1912,7 +2171,7 @@ H5F_decr_nopen_objs(H5F_t *f)
     FUNC_LEAVE_NOAPI(--f->nopen_objs)
 } /* end H5F_decr_nopen_objs() */
 
-
+
 /*-------------------------------------------------------------------------
  * Function: H5F_build_actual_name
  *
@@ -2034,7 +2293,7 @@ done:
     FUNC_LEAVE_NOAPI(ret_value)
 } /* H5F_build_actual_name() */
 
-
+
 /*-------------------------------------------------------------------------
  * Function: H5F_addr_encode_len
  *
@@ -2071,7 +2330,7 @@ H5F_addr_encode_len(size_t addr_len, uint8_t **pp/*in,out*/, haddr_t addr)
     FUNC_LEAVE_NOAPI_VOID
 } /* end H5F_addr_encode_len() */
 
-
+
 /*-------------------------------------------------------------------------
  * Function: H5F_addr_encode
  *
@@ -2095,7 +2354,7 @@ H5F_addr_encode(const H5F_t *f, uint8_t **pp/*in,out*/, haddr_t addr)
     FUNC_LEAVE_NOAPI_VOID
 } /* end H5F_addr_encode() */
 
-
+
 /*-------------------------------------------------------------------------
  * Function: H5F_addr_decode_len
  *
@@ -2159,7 +2418,7 @@ H5F_addr_decode_len(size_t addr_len, const uint8_t **pp/*in,out*/, haddr_t *addr
     FUNC_LEAVE_NOAPI_VOID
 } /* end H5F_addr_decode_len() */
 
-
+
 /*-------------------------------------------------------------------------
  * Function: H5F_addr_decode
  *
@@ -2186,7 +2445,7 @@ H5F_addr_decode(const H5F_t *f, const uint8_t **pp/*in,out*/, haddr_t *addr_p/*o
     FUNC_LEAVE_NOAPI_VOID
 } /* end H5F_addr_decode() */
 
-
+
 /*-------------------------------------------------------------------------
  * Function:    H5F_set_grp_btree_shared
  *
@@ -2212,7 +2471,7 @@ H5F_set_grp_btree_shared(H5F_t *f, H5UC_t *rc)
     FUNC_LEAVE_NOAPI(SUCCEED)
 } /* H5F_set_grp_btree_shared() */
 
-
+
 /*-------------------------------------------------------------------------
  * Function:    H5F_set_sohm_addr
  *
@@ -2237,7 +2496,7 @@ H5F_set_sohm_addr(H5F_t *f, haddr_t addr)
     FUNC_LEAVE_NOAPI(SUCCEED)
 } /* H5F_set_sohm_addr() */
 
-
+
 /*-------------------------------------------------------------------------
  * Function:    H5F_set_sohm_vers
  *
@@ -2262,7 +2521,7 @@ H5F_set_sohm_vers(H5F_t *f, unsigned vers)
     FUNC_LEAVE_NOAPI(SUCCEED)
 } /* H5F_set_sohm_vers() */
 
-
+
 /*-------------------------------------------------------------------------
  * Function:    H5F_set_sohm_nindexes
  *
@@ -2287,7 +2546,7 @@ H5F_set_sohm_nindexes(H5F_t *f, unsigned nindexes)
     FUNC_LEAVE_NOAPI(SUCCEED)
 } /* H5F_set_sohm_nindexes() */
 
-
+
 /*-------------------------------------------------------------------------
  * Function:    H5F_set_store_msg_crt_idx
  *
@@ -2312,7 +2571,7 @@ H5F_set_store_msg_crt_idx(H5F_t *f, hbool_t flag)
     FUNC_LEAVE_NOAPI(SUCCEED)
 } /* H5F_set_store_msg_crt_idx() */
 
-
+
 /*-------------------------------------------------------------------------
  * Function:    H5F_get_file_image
  *
@@ -2428,7 +2687,7 @@ done:
     FUNC_LEAVE_NOAPI(ret_value)
 } /* H5F_get_file_image() */
 
-
+
 /*-------------------------------------------------------------------------
  * Function: H5F_track_metadata_read_retries
  *
@@ -2476,7 +2735,7 @@ done:
     FUNC_LEAVE_NOAPI(ret_value)
 } /* H5F_track_metadata_read_retries() */
 
-
+
 /*-------------------------------------------------------------------------
  * Function: H5F_set_retries
  *
@@ -2512,7 +2771,7 @@ H5F_set_retries(H5F_t *f)
     FUNC_LEAVE_NOAPI(SUCCEED)
 } /* H5F_set_retries() */
 
-
+
 /*-------------------------------------------------------------------------
  * Function:    H5F_object_flush_cb
  *
@@ -2542,7 +2801,7 @@ done:
     FUNC_LEAVE_NOAPI(ret_value)
 } /* H5F_object_flush_cb() */
 
-
+
 /*-------------------------------------------------------------------------
  * Function: H5F__set_base_addr
  *
@@ -2569,7 +2828,7 @@ done:
     FUNC_LEAVE_NOAPI(ret_value)
 } /* end H5F__set_base_addr() */
 
-
+
 /*-------------------------------------------------------------------------
  * Function: H5F__set_eoa
  *
@@ -2596,7 +2855,7 @@ done:
     FUNC_LEAVE_NOAPI(ret_value)
 } /* end H5F__set_eoa() */
 
-
+
 /*-------------------------------------------------------------------------
  * Function: H5F__set_paged_aggr
  *
@@ -2625,7 +2884,7 @@ done:
 } /* end H5F__set_paged_aggr() */
 
 #ifdef H5_HAVE_PARALLEL
-
+
 /*-------------------------------------------------------------------------
  * Function:    H5F_set_coll_md_read
  *
@@ -2650,7 +2909,7 @@ H5F_set_coll_md_read(H5F_t *f, H5P_coll_md_read_flag_t cmr)
 } /* H5F_set_coll_md_read() */
 #endif /* H5_HAVE_PARALLEL */
 
-
+
 /*-------------------------------------------------------------------------
  * Function:    H5F_set_latest_flags
  *
diff --git a/src/H5Fprivate.h b/src/H5Fprivate.h
index 96b8e36..ba94069 100644
--- a/src/H5Fprivate.h
+++ b/src/H5Fprivate.h
@@ -863,6 +863,12 @@ H5_DLL H5F_t *H5F_efc_open(H5F_t *parent, const char *name, unsigned flags,
     hid_t fcpl_id, hid_t fapl_id, hid_t dxpl_id);
 H5_DLL herr_t H5F_efc_close(H5F_t *parent, H5F_t *file);
 
+/* File prefix routines */
+H5_DLL herr_t H5F_build_name(char *prefix, char *file_name, char **full_name);
+H5_DLL char * H5F_getenv_prefix_name(char **env_prefix);
+H5F_t *H5F_prefix_open_file(hid_t plist_id, H5F_t *primary_file, const char *prefix_type,
+        const char *file_name, unsigned file_intent, hid_t fapl_id, hid_t dxpl_id);
+
 /* Global heap CWFS routines */
 H5_DLL herr_t H5F_cwfs_add(H5F_t *f, struct H5HG_heap_t *heap);
 H5_DLL herr_t H5F_cwfs_find_free_heap(H5F_t *f, hid_t dxpl_id, size_t need, haddr_t *addr);
diff --git a/src/H5Lexternal.c b/src/H5Lexternal.c
index b4a173f..bf0a044 100644
--- a/src/H5Lexternal.c
+++ b/src/H5Lexternal.c
@@ -15,7 +15,7 @@
 /* Module Setup */
 /****************/
 
-#define H5G_FRIEND		/*suppress error about including H5Gpkg   */
+#define H5G_FRIEND        /*suppress error about including H5Gpkg   */
 #include "H5Lmodule.h"          /* This source code file is part of the H5L module */
 
 
@@ -25,8 +25,9 @@
 #include "H5private.h"          /* Generic Functions                    */
 #include "H5ACprivate.h"        /* Metadata cache                       */
 #include "H5Eprivate.h"         /* Error handling                       */
+#include "H5Fprivate.h"         /* Files                                */
 #include "H5Gpkg.h"             /* Groups                               */
-#include "H5Iprivate.h"		/* IDs					*/
+#include "H5Iprivate.h"         /* IDs                                  */
 #include "H5Lpkg.h"             /* Links                                */
 #include "H5MMprivate.h"        /* Memory management                    */
 #include "H5Opublic.h"          /* File objects                         */
@@ -79,7 +80,7 @@ static ssize_t H5L_extern_query(const char H5_ATTR_UNUSED * link_name, const voi
 /* Default External Link link class */
 static const H5L_class_t H5L_EXTERN_LINK_CLASS[1] = {{
     H5L_LINK_CLASS_T_VERS,      /* H5L_class_t version            */
-    H5L_TYPE_EXTERNAL,		/* Link type id number            */
+    H5L_TYPE_EXTERNAL,        /* Link type id number            */
     "external",                 /* Link name for debugging        */
     NULL,                       /* Creation callback              */
     NULL,                       /* Move callback                  */
@@ -89,82 +90,10 @@ static const H5L_class_t H5L_EXTERN_LINK_CLASS[1] = {{
     H5L_extern_query            /* Query callback                 */
 }};
 
-
-
-/*--------------------------------------------------------------------------
- * Function: H5L_getenv_prefix_name --
- *
- * Purpose:  Get the first pathname in the list of pathnames stored in ENV_PREFIX,
- *           which is separated by the environment delimiter.
- *           ENV_PREFIX is modified to point to the remaining pathnames
- *           in the list.
- *
- * Return:   A pointer to a pathname
- *
- * Programmer:	Vailin Choi, April 2, 2008
- *
---------------------------------------------------------------------------*/
-static char *
-H5L_getenv_prefix_name(char **env_prefix/*in,out*/)
-{
-    char        *retptr=NULL;
-    char        *strret=NULL;
-
-    FUNC_ENTER_NOAPI_NOINIT_NOERR
-
-    strret = HDstrchr(*env_prefix, H5_COLON_SEPC);
-    if (strret == NULL) {
-        retptr = *env_prefix;
-        *env_prefix = strret;
-    } else {
-        retptr = *env_prefix;
-        *env_prefix = strret + 1;
-        *strret = '\0';
-    }
-
-    FUNC_LEAVE_NOAPI(retptr)
-} /* end H5L_getenv_prefix_name() */
-
-
-/*--------------------------------------------------------------------------
- * Function: H5L_build_name
- *
- * Purpose:  Prepend PREFIX to FILE_NAME and store in FULL_NAME
- *
- * Return:   Non-negative on success/Negative on failure
- *
- * Programmer:	Vailin Choi, April 2, 2008
- *
---------------------------------------------------------------------------*/
-static herr_t
-H5L_build_name(char *prefix, char *file_name, char **full_name/*out*/)
-{
-    size_t      prefix_len;             /* length of prefix */
-    size_t      fname_len;              /* Length of external link file name */
-    herr_t      ret_value = SUCCEED;    /* Return value */
-
-    FUNC_ENTER_NOAPI_NOINIT
-
-    prefix_len = HDstrlen(prefix);
-    fname_len = HDstrlen(file_name);
-
-    /* Allocate a buffer to hold the filename + prefix + possibly the delimiter + terminating null byte */
-    if(NULL == (*full_name = (char *)H5MM_malloc(prefix_len + fname_len + 2)))
-        HGOTO_ERROR(H5E_RESOURCE, H5E_NOSPACE, FAIL, "unable to allocate filename buffer")
-
-    /* Compose the full file name */
-    HDsnprintf(*full_name, (prefix_len + fname_len + 2), "%s%s%s", prefix,
-        (H5_CHECK_DELIMITER(prefix[prefix_len - 1]) ? "" : H5_DIR_SEPS), file_name);
-
-done:
-    FUNC_LEAVE_NOAPI(ret_value)
-} /* H5L_build_name() */
-
-
 /*-------------------------------------------------------------------------
- * Function:	H5L_extern_traverse
+ * Function:    H5L_extern_traverse
  *
- * Purpose:	Default traversal function for external links. This can
+ * Purpose:    Default traversal function for external links. This can
  *              be overridden using H5Lregister().
  *
  *              Given a filename and path packed into the link udata,
@@ -173,25 +102,25 @@ done:
  *              link access property list, appends that prefix to the
  *              filename being opened.
  *
- * Return:	ID of the opened object on success/Negative on failure
+ * Return:    ID of the opened object on success/Negative on failure
  *
- * Programmer:	James Laird
+ * Programmer:    James Laird
  *              Monday, July 10, 2006
  * Modifications:
- *		Vailin Choi, April 2, 2008
- *		Add handling to search for the target file
- *		See description in RM: H5Lcreate_external
+ *        Vailin Choi, April 2, 2008
+ *        Add handling to search for the target file
+ *        See description in RM: H5Lcreate_external
  *
- *		Vailin Choi; Sept. 12th, 2008; bug #1247
- *		Retrieve the file access property list identifer that is set
- *		for link access property via H5Pget_elink_fapl().
- *		If the return value is H5P_DEFAULT, the parent's file access
- *		property is used to H5F_open() the target file;
- *		Otherwise, the file access property retrieved from H5Pget_elink_fapl()
- *		is used to H5F_open() the target file.
+ *        Vailin Choi; Sept. 12th, 2008; bug #1247
+ *        Retrieve the file access property list identifer that is set
+ *        for link access property via H5Pget_elink_fapl().
+ *        If the return value is H5P_DEFAULT, the parent's file access
+ *        property is used to H5F_open() the target file;
+ *        Otherwise, the file access property retrieved from H5Pget_elink_fapl()
+ *        is used to H5F_open() the target file.
  *
- *		Vailin Choi; Nov 2010
- *		Free memory pointed to by tmp_env_prefix for HDF5_EXT_PREFIX case.
+ *        Vailin Choi; Nov 2010
+ *        Free memory pointed to by tmp_env_prefix for HDF5_EXT_PREFIX case.
  *
  *-------------------------------------------------------------------------
  */
@@ -200,13 +129,11 @@ H5L_extern_traverse(const char H5_ATTR_UNUSED *link_name, hid_t cur_group,
     const void *_udata, size_t H5_ATTR_UNUSED udata_size, hid_t lapl_id)
 {
     H5P_genplist_t *plist;              /* Property list pointer */
-    char       *my_prefix;              /* Library's copy of the prefix */
     H5G_loc_t   root_loc;               /* Location of root group in external file */
     H5G_loc_t   loc;                    /* Location of object */
-    H5F_t	*ext_file = NULL;	/* File struct for external file */
+    H5F_t    *ext_file = NULL;    /* File struct for external file */
     const uint8_t *p = (const uint8_t *)_udata;  /* Pointer into external link buffer */
     const char *file_name;              /* Name of file containing external link's object */
-    char *full_name = NULL;             /* File name with prefix */
     const char  *obj_name;              /* Name external link's object */
     size_t      fname_len;              /* Length of external link file name */
     unsigned    intent;                 /* File access permissions */
@@ -215,11 +142,8 @@ H5L_extern_traverse(const char H5_ATTR_UNUSED *link_name, hid_t cur_group,
     hid_t       ext_obj = -1;           /* ID for external link's object */
     char        *parent_group_name = NULL;/* Temporary pointer to group name */
     char        local_group_name[H5L_EXT_TRAVERSE_BUF_SIZE];  /* Local buffer to hold group name */
-    char        *temp_file_name = NULL; /* Temporary pointer to file name */
-    size_t      temp_file_name_len;     /* Length of temporary file name */
-    char        *actual_file_name = NULL; /* Parent file's actual name */
     H5P_genplist_t  *fa_plist;          /* File access property list pointer */
-    H5F_close_degree_t 	fc_degree = H5F_CLOSE_WEAK;  /* File close degree for target file */
+    H5F_close_degree_t     fc_degree = H5F_CLOSE_WEAK;  /* File close degree for target file */
     hid_t       dxpl_id = H5AC_ind_read_dxpl_id; /* dxpl used by library */
     hid_t ret_value = H5I_INVALID_HID;  /* Return value */
 
@@ -266,7 +190,7 @@ H5L_extern_traverse(const char H5_ATTR_UNUSED *link_name, hid_t cur_group,
         intent = H5F_INTENT(loc.oloc->file);
 
     if((fapl_id == H5P_DEFAULT) && ((fapl_id = H5F_get_access_plist(loc.oloc->file, FALSE)) < 0))
-	HGOTO_ERROR(H5E_LINK, H5E_CANTGET, FAIL, "can't get parent's file access property list")
+        HGOTO_ERROR(H5E_LINK, H5E_CANTGET, FAIL, "can't get parent's file access property list")
 
     /* Get callback_info */
     if(H5P_get(plist, H5L_ACS_ELINK_CB_NAME, &cb_info) < 0)
@@ -274,7 +198,7 @@ H5L_extern_traverse(const char H5_ATTR_UNUSED *link_name, hid_t cur_group,
 
     /* Get file access property list */
     if(NULL == (fa_plist = H5P_object_verify(fapl_id, H5P_FILE_ACCESS)))
-	HGOTO_ERROR(H5E_ATOM, H5E_BADATOM, FAIL, "can't find object for ID")
+        HGOTO_ERROR(H5E_ATOM, H5E_BADATOM, FAIL, "can't find object for ID")
 
     /* Make callback if it exists */
     if(cb_info.func) {
@@ -314,143 +238,11 @@ H5L_extern_traverse(const char H5_ATTR_UNUSED *link_name, hid_t cur_group,
 
     /* Set file close degree for new file to "weak" */
     if(H5P_set(fa_plist, H5F_ACS_CLOSE_DEGREE_NAME, &fc_degree) < 0)
-	HGOTO_ERROR(H5E_PLIST, H5E_CANTSET, FAIL, "can't set file close degree")
-
-    /*
-     * Start searching for the target file
-     */
-
-    /* Simplify intent flags for open calls */
-    intent &= (H5F_ACC_RDWR | H5F_ACC_SWMR_WRITE | H5F_ACC_SWMR_READ);
-
-    /* Copy the file name to use */
-    if(NULL == (temp_file_name = H5MM_strdup(file_name)))
-        HGOTO_ERROR(H5E_RESOURCE, H5E_NOSPACE, FAIL, "memory allocation failed")
-    temp_file_name_len = HDstrlen(temp_file_name);
-
-    /* target file_name is an absolute pathname: see RM for detailed description */
-    if(H5_CHECK_ABSOLUTE(file_name) || H5_CHECK_ABS_PATH(file_name)) {
-        /* Try opening file */
-        if(NULL == (ext_file = H5F_efc_open(loc.oloc->file, file_name, intent, H5P_FILE_CREATE_DEFAULT, fapl_id, dxpl_id))) {
-            char *ptr;
-
-            H5E_clear_stack(NULL);
-
-            /* get last component of file_name */
-	    H5_GET_LAST_DELIMITER(file_name, ptr)
-	    HDassert(ptr);
-
-            /* Increment past delimiter */
-            ptr++;
-
-            /* Copy into the temp. file name */
-	    HDstrncpy(temp_file_name, ptr, temp_file_name_len);
-            temp_file_name[temp_file_name_len - 1] = '\0';
-        } /* end if */
-    } /* end if */
-    else if(H5_CHECK_ABS_DRIVE(file_name)) {
-        /* Try opening file */
-        if(NULL == (ext_file = H5F_efc_open(loc.oloc->file, file_name, intent, H5P_FILE_CREATE_DEFAULT, fapl_id, dxpl_id))) {
-
-            H5E_clear_stack(NULL);
-
-	    /* strip "<drive-letter>:" */
-	    HDstrncpy(temp_file_name, &file_name[2], temp_file_name_len);
-            temp_file_name[temp_file_name_len - 1] = '\0';
-	} /* end if */
-    } /* end if */
-
-    /* try searching from paths set in the environment variable */
-    if(ext_file == NULL) {
-        char *env_prefix;
-
-        if(NULL != (env_prefix = HDgetenv("HDF5_EXT_PREFIX"))) {
-            char *tmp_env_prefix, *saved_env;
-
-            if(NULL == (saved_env = tmp_env_prefix = H5MM_strdup(env_prefix)))
-                HGOTO_ERROR(H5E_LINK, H5E_NOSPACE, FAIL, "memory allocation failed")
-
-            while((tmp_env_prefix) && (*tmp_env_prefix)) {
-                char *out_prefix_name;
-
-                out_prefix_name = H5L_getenv_prefix_name(&tmp_env_prefix/*in,out*/);
-                if(out_prefix_name && (*out_prefix_name)) {
-                    if(H5L_build_name(out_prefix_name, temp_file_name, &full_name/*out*/) < 0) {
-			saved_env = (char *)H5MM_xfree(saved_env);
-                        HGOTO_ERROR(H5E_LINK, H5E_CANTGET, FAIL, "can't prepend prefix to filename")
-		    } /* end if */
-
-                    ext_file = H5F_efc_open(loc.oloc->file, full_name, intent, H5P_FILE_CREATE_DEFAULT, fapl_id, dxpl_id);
-                    full_name = (char *)H5MM_xfree(full_name);
-                    if(ext_file != NULL)
-                        break;
-                    H5E_clear_stack(NULL);
-                } /* end if */
-            } /* end while */
-	    saved_env = (char *)H5MM_xfree(saved_env);
-        } /* end if */
-    } /* end if */
-
-    /* try searching from property list */
-    if(ext_file == NULL) {
-        if(H5P_peek(plist, H5L_ACS_ELINK_PREFIX_NAME, &my_prefix) < 0)
-            HGOTO_ERROR(H5E_PLIST, H5E_CANTGET, FAIL, "can't get external link prefix")
-        if(my_prefix) {
-            if(H5L_build_name(my_prefix, temp_file_name, &full_name/*out*/) < 0)
-                HGOTO_ERROR(H5E_LINK, H5E_CANTGET, FAIL, "can't prepend prefix to filename")
-            if(NULL == (ext_file = H5F_efc_open(loc.oloc->file, full_name, intent, H5P_FILE_CREATE_DEFAULT, fapl_id, dxpl_id)))
-                H5E_clear_stack(NULL);
-            full_name = (char *)H5MM_xfree(full_name);
-        } /* end if */
-    } /* end if */
-
-    /* try searching from main file's "extpath": see description in H5F_open() & H5_build_extpath() */
-    if(ext_file == NULL) {
-        char *extpath;
-
-        if(NULL != (extpath = H5F_EXTPATH(loc.oloc->file))) {
-            if(H5L_build_name(extpath, temp_file_name, &full_name/*out*/) < 0)
-                HGOTO_ERROR(H5E_LINK, H5E_CANTGET, FAIL, "can't prepend prefix to filename")
-            if(NULL == (ext_file = H5F_efc_open(loc.oloc->file, full_name, intent, H5P_FILE_CREATE_DEFAULT, fapl_id, dxpl_id)))
-                H5E_clear_stack(NULL);
-            full_name = (char *)H5MM_xfree(full_name);
-        } /* end if */
-    } /* end if */
-
-    /* try the relative file_name stored in temp_file_name */
-    if(ext_file == NULL) {
-        if(NULL == (ext_file = H5F_efc_open(loc.oloc->file, temp_file_name, intent, H5P_FILE_CREATE_DEFAULT, fapl_id, dxpl_id)))
-            H5E_clear_stack(NULL);
-    } /* end if */
-
-    /* try the 'resolved' name for the parent file (i.e. the name after symlinks
-     * were resolved)
-     */
-    if(ext_file == NULL) {
-        char *ptr = NULL;
-
-        /* Copy resolved file name */
-        if(NULL == (actual_file_name = H5MM_strdup(H5F_ACTUAL_NAME(loc.oloc->file))))
-            HGOTO_ERROR(H5E_LINK, H5E_CANTALLOC, FAIL, "can't duplicate resolved file name string")
-
-        /* get last component of file_name */
-        H5_GET_LAST_DELIMITER(actual_file_name, ptr)
-        if(!ptr)
-            HGOTO_ERROR(H5E_LINK, H5E_CANTOPENFILE, FAIL, "unable to open external file, external link file name = '%s', temp_file_name = '%s'", file_name, temp_file_name)
-
-        /* Truncate filename portion from actual file name path */
-        *ptr = '\0';
-
-        /* Build new file name for the external file */
-        if(H5L_build_name(actual_file_name, temp_file_name, &full_name/*out*/) < 0)
-            HGOTO_ERROR(H5E_LINK, H5E_CANTGET, FAIL, "can't prepend prefix to filename")
-
-        /* Try opening with the resolved name */
-        if(NULL == (ext_file = H5F_efc_open(loc.oloc->file, full_name, intent, H5P_FILE_CREATE_DEFAULT, fapl_id, dxpl_id)))
-            HGOTO_ERROR(H5E_LINK, H5E_CANTOPENFILE, FAIL, "unable to open external file, external link file name = '%s', temp_file_name = '%s'", file_name, temp_file_name)
-        full_name = (char *)H5MM_xfree(full_name);
-    } /* end if */
+        HGOTO_ERROR(H5E_PLIST, H5E_CANTSET, FAIL, "can't set file close degree")
 
+    /* Search for the target file */
+    if(NULL == (ext_file = H5F_prefix_open_file(lapl_id, loc.oloc->file, H5L_ACS_ELINK_PREFIX_NAME, file_name, intent, fapl_id, dxpl_id)))
+        HGOTO_ERROR(H5E_LINK, H5E_CANTOPENFILE, FAIL, "unable to open external file, external link file name = '%s'", file_name)
 
     /* Retrieve the "group location" for the file's root group */
     if(H5G_root_loc(ext_file, &root_loc) < 0)
@@ -471,10 +263,6 @@ done:
         HDONE_ERROR(H5E_LINK, H5E_CANTCLOSEFILE, FAIL, "problem closing external file")
     if(parent_group_name && parent_group_name != local_group_name)
         parent_group_name = (char *)H5MM_xfree(parent_group_name);
-    full_name = (char *)H5MM_xfree(full_name);
-    temp_file_name = (char *)H5MM_xfree(temp_file_name);
-    actual_file_name = (char *)H5MM_xfree(actual_file_name);
-
     if(ret_value < 0) {
         /* Close object if it's open and something failed */
         if(ext_obj >= 0 && H5I_dec_ref(ext_obj) < 0)
@@ -484,20 +272,20 @@ done:
     FUNC_LEAVE_NOAPI(ret_value)
 } /* end H5L_extern_traverse() */
 
-
+
 /*-------------------------------------------------------------------------
- * Function:	H5L_extern_query
+ * Function:    H5L_extern_query
  *
- * Purpose:	Default query function for external links. This can
+ * Purpose:    Default query function for external links. This can
  *              be overridden using H5Lregister().
  *
  *              Returns the size of the link's user data. If a buffer of
  *              is provided, copies at most buf_size bytes of the udata
  *              into it.
  *
- * Return:	Size of buffer on success/Negative on failure
+ * Return:    Size of buffer on success/Negative on failure
  *
- * Programmer:	James Laird
+ * Programmer:    James Laird
  *              Monday, July 10, 2006
  *
  *-------------------------------------------------------------------------
@@ -534,23 +322,23 @@ done:
     FUNC_LEAVE_NOAPI(ret_value)
 } /* end H5L_extern_query() */
 
-
+
 /*-------------------------------------------------------------------------
- * Function:	H5Lcreate_external
+ * Function:    H5Lcreate_external
  *
- * Purpose:	Creates an external link from LINK_NAME to OBJ_NAME.
+ * Purpose:    Creates an external link from LINK_NAME to OBJ_NAME.
  *
  *              External links are links to objects in other HDF5 files.  They
  *              are allowed to "dangle" like soft links internal to a file.
  *              FILE_NAME is the name of the file that OBJ_NAME is is contained
  *              within.  If OBJ_NAME is given as a relative path name, the
  *              path will be relative to the root group of FILE_NAME.
- *		LINK_NAME is interpreted relative to LINK_LOC_ID, which is
+ *              LINK_NAME is interpreted relative to LINK_LOC_ID, which is
  *              either a file ID or a group ID.
  *
- * Return:	Non-negative on success/Negative on failure
+ * Return:    Non-negative on success/Negative on failure
  *
- * Programmer:	Quincey Koziol
+ * Programmer:    Quincey Koziol
  *              Wednesday, May 18, 2005
  *
  *-------------------------------------------------------------------------
@@ -559,14 +347,14 @@ herr_t
 H5Lcreate_external(const char *file_name, const char *obj_name,
     hid_t link_loc_id, const char *link_name, hid_t lcpl_id, hid_t lapl_id)
 {
-    H5G_loc_t	link_loc;               /* Group location to create link */
-    char       *norm_obj_name = NULL;	/* Pointer to normalized current name */
+    H5G_loc_t    link_loc;               /* Group location to create link */
+    char       *norm_obj_name = NULL;    /* Pointer to normalized current name */
     void       *ext_link_buf = NULL;    /* Buffer to contain external link */
     size_t      buf_size;               /* Size of buffer to hold external link */
     size_t      file_name_len;          /* Length of file name string */
     size_t      norm_obj_name_len;      /* Length of normalized object name string */
     uint8_t    *p;                      /* Pointer into external link buffer */
-    hid_t       dxpl_id = H5AC_ind_read_dxpl_id; /* dxpl used by library */ 
+    hid_t       dxpl_id = H5AC_ind_read_dxpl_id; /* dxpl used by library */
     herr_t      ret_value = SUCCEED;    /* Return value */
 
     FUNC_ENTER_API(FAIL)
@@ -575,13 +363,13 @@ H5Lcreate_external(const char *file_name, const char *obj_name,
 
     /* Check arguments */
     if(!file_name || !*file_name)
-	HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "no file name specified")
+        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "no file name specified")
     if(!obj_name || !*obj_name)
-	HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "no object name specified")
+        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "no object name specified")
     if(H5G_loc(link_loc_id, &link_loc) < 0)
         HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "not a location")
     if(!link_name || !*link_name)
-	HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "no link name specified")
+        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "no link name specified")
 
     /* Get normalized copy of the link target */
     if(NULL == (norm_obj_name = H5G_normalize(obj_name)))
@@ -616,7 +404,7 @@ done:
     FUNC_LEAVE_API(ret_value)
 } /* end H5Lcreate_external() */
 
-
+
 /*-------------------------------------------------------------------------
  * Function: H5L_register_external
  *
@@ -645,7 +433,7 @@ done:
     FUNC_LEAVE_NOAPI(ret_value)
 } /* end H5L_register_external() */
 
-
+
 /*-------------------------------------------------------------------------
  * Function: H5Lunpack_elink_val
  *