nbdkit_realpath(3) NBDKIT nbdkit_realpath(3) NAME nbdkit_realpath, nbdkit_absolute_path - convert relative to absolute paths for nbdkit SYNOPSIS #include <nbdkit-plugin.h> char *nbdkit_realpath (const char *filename); char *nbdkit_absolute_path (const char *filename); DESCRIPTION nbdkit(1) usually (not always) changes directory to / before it starts serving connections. This means that any relative paths passed during con- figuration will not work when the server is running. In a naive implemen- tation 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 de- scribed 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 ac- cess 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 ab- solute 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 ex- ists. This function works only when used in the ".config", ".config_complete" and ".get_ready" callbacks. RETURN VALUE 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". LANGUAGE BINDINGS In nbdkit-ocaml-plugin(3): NBDKit.realpath : string -> string HISTORY "nbdkit_absolute_path" was present in nbdkit 0.1.0. "nbdkit_realpath" was added in nbdkit 1.4. SEE ALSO nbdkit(1), nbdkit-plugin(3), nbdkit-filter(3). AUTHORS Richard W.M. Jones COPYRIGHT Copyright Red Hat LICENSE Redistribution and use in source and binary forms, with or without modifi- cation, are permitted provided that the following conditions are met: * Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer. * Redistributions in binary form must reproduce the above copyright no- tice, this list of conditions and the following disclaimer in the docu- mentation and/or other materials provided with the distribution. * Neither the name of Red Hat nor the names of its contributors may be used to endorse or promote products derived from this software without specific prior written permission. THIS SOFTWARE IS PROVIDED BY RED HAT AND CONTRIBUTORS ''AS IS'' AND ANY EX- PRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DIS- CLAIMED. IN NO EVENT SHALL RED HAT OR CONTRIBUTORS BE LIABLE FOR ANY DI- RECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SER- VICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABIL- ITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAM- AGE. nbdkit-1.46.2 2026-08-30 nbdkit_realpath(3)
NAME | SYNOPSIS | DESCRIPTION | RETURN VALUE | LANGUAGE BINDINGS | HISTORY | SEE ALSO | AUTHORS | COPYRIGHT | LICENSE
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