How can I use fopen() and write a file to disk? When I run the function below:
void file_pass() { printf("File pass\n");
char buffer[] = {'s', 'a', 'm'};
FILE* f = fopen("temp","w"); fwrite(buffer, 1, 3, f); fclose(f); }
I get the error:
no plugin found for open("temp", int)
Can anyone offer some advice?
I am using L4Pistachio as my base.
Hello Sam,
How can I use fopen() and write a file to disk? When I run the function below:
...
I get the error:
no plugin found for open("temp", int)
Can anyone offer some advice?
on Genode, there is no global file system where to fetch files from. Instead, there may be a variety of different sources. For example, ROM files provided by core, or files stored on a CDROM image with an ISO9600 file system. To accommodate this variety of options, our libc offers a plugin mechanism that allows different back ends to manage specific file handles. When using the libc with no plugin, you are prompted with the message you just got. It tells us that no plugin showed any interest in caring for the specified file "temp".
If you want to work with files stored on a VFAT-formatted block device, you will find the libc_ffat plugin useful. It uses the ffat library as file-system implementation. You can download this library from within the libports repository via
cd libports make prepare PKG=ffat
For a quick test, I recommend you to try out the run script 'libports/run/libc_ffat.run'. You can execute it directly from the build directory by issuing
make run/libc_ffat
This run script will build and execute a test case that exercises file operations such as reading, writing, and some directory operations. See the code at 'libports/src/test/libc_ffat/main.cc' for the details.
For accessing ROM files (such as those provided by core or the iso9660 server) via libc file functions, I have just recently added a new 'libc_rom' plugin. It is not merged to master yet. But you can get it from the staging branch:
https://github.com/genodelabs/genode/commit/54cb49583b47139c48b08f53d06b25eb...
I hope these pointers will be helpful. Good luck!
Norman
-
Norman Feske -
Sam Kerr