syspkg/docs/porting.md

Porting The System Packaging Library

When porting to new operating systems, edit src/lib/config.h and tailor it to your needs. Take a look at one of the config.OS.h files to get ideas.

To integrate libsyspkg with your OS, all you need is a libc (truth to be told, a fairly complete one with Berkeley sockets, but that's where the list of dependencies end). If you have a special, non-socket based networking API, then you'll have to edit src/lib/mbedtls/library/net_sockets.c. It already has the required ifdefs for the WIN32 API. That file isn't provided by libsyspkg rather by mbedtls. Alternatively you can turn networking support entirely off by editing src/lib/mbedtls/include/mbedtls/config.h and commenting out the #define MBEDTLS_NET_C line. You'll still be able to use local files and "file://" URLs in repositories, package meta info and payloads. This is enough if your OS is distributed on a CDROM for example.

If your target OS is a POSIX compliant one, nothing else left to do. If it isn't, then take a look at src/lib/files.c, all file system related functions are implemented there. That's one of the two files in the source tree which have ifdef OS guards. Besides of POSIX, it is also written for the WIN32 API. There's one more OS specific call in src/lib/postinst.c, which should execute a command with specific environment variables (also written for both POSIX and WIN32 API). All the other files contain only OS independent, portable C code.