tree-wide: remove Emacs lines from all files This should be handled fine now by .dir-locals.el, so need to carry that stuff in every file.

tree-wide: sort includes Sort the includes accoding to the new coding style.

install: follow unit file symlinks in /usr, but not /etc when looking for [Install] data Some distributions use alias unit files via symlinks in /usr to cover for legacy service names. With this change we'll allow "systemctl enable" on such aliases. Previously, our rule was that symlinks are user configuration that "systemctl enable" + "systemctl disable" creates and removes, while unit files is where the instructions to do so are store. As a result of the rule we'd never read install information through symlinks, since that would mix enablement state with installation instructions. Now, the new rule is that only symlinks inside of /etc are configuration. Unit files, and symlinks in /usr are now valid for installation instructions. This patch is quite a rework of the whole install logic, and makes the following addional changes: - Adds a complete test "test-instal-root" that tests the install logic pretty comprehensively. - Never uses canonicalize_file_name(), because that's incompatible with operation relative to a specific root directory. - unit_file_get_state() is reworked to return a proper error, and returns the state in a call-by-ref parameter. This cleans up confusion between the enum type and errno-like errors. - The new logic puts a limit on how long to follow unit file symlinks: it will do so only for 64 steps at max. - The InstallContext object's fields are renamed to will_process and has_processed (will_install and has_installed) since they are also used for deinstallation and all kinds of other operations. - The root directory is always verified before use. - install.c is reordered to place the exported functions together. - Stricter rules are followed when traversing symlinks: the unit suffix must say identical, and it's not allowed to link between regular units and templated units. - Various modernizations - The "invalid" unit file state has been renamed to "bad", in order to avoid confusion between UNIT_FILE_INVALID and _UNIT_FILE_STATE_INVALID. Given that the state should normally not be seen and is not documented this should not be a problematic change. The new name is now documented however. Fixes #1375, #1718, #1706

remove unused includes This patch removes includes that are not used. The removals were found with include-what-you-use which checks if any of the symbols from a header is in use.

test: only use assert_se The asserts used in the tests should never be allowed to be optimized away

hashmap: introduce hash_ops to make struct Hashmap smaller It is redundant to store 'hash' and 'compare' function pointers in struct Hashmap separately. The functions always comprise a pair. Store a single pointer to struct hash_ops instead. systemd keeps hundreds of hashmaps, so this saves a little bit of memory.

install: beef up preset logic to limit to only enable or only disable, and do all-unit preset operations The new "systemctl preset-all" command may now be used to put all installed units back into the enable/disable state the vendor/admin encoded in preset files. Also, introduce "systemctl --preset-mode=enable-only" and "systemctl --preset-mode=disable-only" to only apply the enable or only the disable operations of a "systemctl preset" or "systemctl preset-all" operation. "systemctl preset-all" implements this RFE: https://bugzilla.redhat.com/show_bug.cgi?id=630174

Get rid of our reimplementation of basename The only problem is that libgen.h #defines basename to point to it's own broken implementation instead of the GNU one. This can be fixed by #undefining basename.

util: split-out path-util.[ch]

test: test tools should still be in the src/ directory