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The VFS library can be used in single-threaded or multi-threaded environments and depending on that, signals are handled by the same thread which uses the VFS library or possibly by a different thread. If a VFS plugin needs to block to wait for a signal, there is currently no way which works reliably in both environments. For this reason, this commit makes the interface of the VFS library nonblocking, similar to the File_system session interface. The most important changes are: - Directories are created and opened with the 'opendir()' function and the directory entries are read with the recently introduced 'queue_read()' and 'complete_read()' functions. - Symbolic links are created and opened with the 'openlink()' function and the link target is read with the 'queue_read()' and 'complete_read()' functions and written with the 'write()' function. - The 'write()' function does not wait for signals anymore. This can have the effect that data written by a VFS library user has not been processed by a file system server yet when the library user asks for the size of the file or closes it (both done with RPC functions at the file system server). For this reason, a user of the VFS library should request synchronization before calling 'stat()' or 'close()'. To make sure that a file system server has processed all write request packets which a client submitted before the synchronization request, synchronization is now requested at the file system server with a synchronization packet instead of an RPC function. Because of this change, the synchronization interface of the VFS library is now split into 'queue_sync()' and 'complete_sync()' functions. Fixes #2399 |
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This directory contains ports of popular 3rd-party software to Genode. Usage ----- The tool './tool/ports/prepare_port' in the toplevel directory automates the task of downloading and preparing the library source codes. You can select individual packages that have to be prepared by specifying their base names (without the version number) as command-line argument. For example, the following command prepares both the C library and the Freetype library: ! ./tool/ports/prepare_port libc freetype To compile and link against 3rd-party libraries of the 'libports' repository, you have to include the repository into the build process by appending it to the 'REPOSITORIES' declaration of your '<build-dir>/etc/build.conf' file. Under the hood -------------- For each library, there is a file contained in the 'libports/ports/' subdirectory. The file is named after the library and contains the library-specific rules for downloading the source code and installing header files. How does 'libports' relate to the other repositories? ----------------------------------------------------- Most libraries hosted in the 'libports' repository expect a complete C library, which is provided with the 'libc' package. Please do not forget to prepare the libc package when using any of the other libports packages. The libc, in turn, depends on the 'os' repository for its back end. Because the 'os' repository is the home of the dynamic linker, libraries contained in 'libports' are safe to assume the presence of the dynamic linker and, thus, should be built as shared libraries.