Well, the problem is, you only changed the problem. Now instead of depending of a specific init system, you're depending of a specific implementation of daemon(

Well, the problem is, you only changed the problem. Now instead of depending of a specific init system, you're depending of a specific implementation of daemon() function (which I imagine is not really standard, since if it was glibc would implement it correctly). Maybe you could create daemon_correctly() function that was guarantee to implement daemon as it should, but you would incur the risk of having the case of strlcpy() again (glibc didn't added this function since the maintainer said it was messy and bloated, so almost no software used it). And anyway, correctly daemonizing is only part of what systemd got right. I think the fact that you don't need to track services with random programs anymore (since systemd knows each and every process parent thanks to cgroups) is something much more interesting than just getting daemon() right.