nbdkit_realpath, nbdkit_absolute_path - convert relative to absolute paths for nbdkit

       Richard W.M. Jones

       Copyright Red Hat

nbdkit(1) usually (not always) changes directory to / before it starts serving connections.  This means
       that any relative paths passed during configuration will not work when the server is running.  In a naive
       implementation of a plugin, a configuration like

        nbdkit plugin file=disk.img

       might attempt to open /disk.img instead of the file in the user's current directory.

       To avoid this problem, you can:

       •   convert relative paths to absolute paths using one of the functions described here, or

       •   open the file at configure time and store the file descriptor.

   nbdkit_realpath
       The  utility function "nbdkit_realpath" converts any path to an absolute path, resolving symlinks.  Under
       the hood it uses the realpath(3) function, and thus it fails if the path does not exist,  or  it  is  not
       possible to access components of the path.

       This function works only when used in the ".config", ".config_complete" and ".get_ready" callbacks.

   nbdkit_absolute_path
       The  utility  function  "nbdkit_absolute_path"  converts any path to an absolute path: if it is relative,
       then all this function does is prepend the current working directory to the path, with no extra checks.

       Unlike "nbdkit_realpath", this function does not check that the file exists.

       This function works only when used in the ".config", ".config_complete" and ".get_ready" callbacks.

       "nbdkit_absolute_path" was present in nbdkit 0.1.0.

       "nbdkit_realpath" was added in nbdkit 1.4.

       In nbdkit-ocaml-plugin(3):

        NBDKit.realpath : string -> string

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nbdkit-1.42.6                                      2025-08-01                                 nbdkit_realpath(3)

       nbdkit_realpath, nbdkit_absolute_path - convert relative to absolute paths for nbdkit

       On success these functions return a newly allocated string.  The returned string must  be  freed  by  the
       caller.

       On error these call nbdkit_error(3) and return "NULL".

nbdkit(1), nbdkit-plugin(3), nbdkit-filter(3).

        #include <nbdkit-plugin.h>

        char *nbdkit_realpath (const char *filename);
        char *nbdkit_absolute_path (const char *filename);