Porting software to MINIX from Linux or FreeBSD is non-trivial in most cases, but not exactly rocket science either. A major part of the work often has to do with altering/extending makefiles or build scripts. Recoding major parts of a piece of software generally is required for only software that does some or all of its work in kernel space. You can help MINIX by porting packages!
This page shall serve as an entry-point for developers wishing to port POSIX applications (e.g., from Linux) to MINIX 3.
A fair number of applications already were ported, thanks to the efforts of our contributors. Check out MINIX 3's download areas for ported packages before trying to do any port; and, see whether your favorite package already is available.
If not, follow this recipe:
Several packages were portable from the start; that is, no source files needed patching, in order to compile under MINIX 3. You can use these packages as references for portable coding practices:
CSSC ascii atk automake avra bc bchunk bcrypt btyacc catdoc cpio ctags diffutils libiconv libmcrypt libpng links lzo lzop m4 mdf2iso nano nasm neon nomarch pkg prng pstotext psutils readline rman sed slang slrn src2tex wdiff webcpp whichman zlib
First, get the configure script to run. Some scripts use shell features not supported by the ASH shell that is the default in MINIX. In that case, use another shell, such as BASH. Similarly, the make which comes with MINIX also has some limitations. If it gives any error messages, try using GNU Make (gmake) instead.
At the least, you probably will need to add detection of the uname string returned by MINIX. That case often can be handled in the same way as other POSIX systems, such as Linux and BSD.
Attempt to compile the program. If you encounter many unexpected syntax errors, the source code
might rely on C99 features or GCC extensions of the C language. One typical example is using
comments rather than
*/ comments. The single-line comments are allowed in C99; but, ACK does not
implement the C99 standard unfortunately. In such cases, it's best to compile the program with GCC.
At first, do not implement missing library functions, but only declare them in header files. That way, you will be able to see which are the most important missing functions, before doing much work. Based on the missing functions, it then is possible to determine whether or not porting is feasible. For example, it might not be possible to port programs which use threads or memory-mapped files, without fundamental changes. Such ports can be delayed until the required functionality is available in MINIX. In that case, you may add both the port and the missing features to the wish list, specifying that the unavailability of the latter blocks the former.
If you added declarations, as recommended in the previous section, eventually you will receive a linker error showing which symbols were used but not defined. That would be the time to implement those missing library functions, preferably in such a way that they easily can be moved into the MINIX libraries, later on. The man pages on the Open Group website are a good source of information about what such calls should do exactly.
Warnings emitted by the C compiler are a good source of information on what might be wrong in the
program you ported. It is preferable to eliminate all warnings, as that might save you a great deal
of time on testing. Although cc provides some warnings, do attempt to compile your program in
gcc with the
-W flags, for maximum compiler assistance.
Testing and fixing bugs can take considerable time for software with poor portability and software that uses features missing in MINIX. Often, programs come with test suites that provide a good starting point.
__minixpreprocessor symbol indicates when C code is being compiled on MINIX.
-funsigned-char” was added to the CFLAGS.