clean up the status codes used

[anbe42]

Right now dkms uses about 15 different exit codes, most of them are used for several quite different error conditions.

# Exit status values and error messages used by dkms:
# (as parameters to die, diewarn, report_build_problem, exit)
#       
# 0: global: SUCCESS
# 0: remove_module(): Remove cancelled because --rpm_safe_upgrade scenario detected.
# 1: ldtarball: You must be root to use this command with the --force option.
# 1: check_root(): You must be root to use this command.
# 1: check_rw_dkms_tree(): No write access to DKMS tree at ...
# 1: mktemp_or_die(): Unable to make temporary file/directory.
# 1: check_module_args(): Arguments <module> and <module-version> are not specified.
# 1: prepare_kernel(): Your kernel headers for kernel ... cannot be found ...
# 1: run_match(): Invalid number of parameters passed.
# 1: global: If more than one arch is specified on the command line, then there "must be an equal number of kernel versions also specified (1:1 relationship).
# 2: global: Unknown option: ...
# 2: global: You cannot specify a kernel version and also specify --all on the command line.
# 2: run_match(): The templatekernel and the specified kernel version are the same.
# 2: add_module(): Could not find module source directory.
# 2: load_tarball(): ... does not exist.
# 3: global: You cannot specify an arch and also specify --all on the command line.
# 3: load_tarball(): Tarball does not appear to be a correctly formed DKMS archive. No dkms.conf found within it.
# 3: run_match(): The module: $module is not located in the DKMS tree.
# 3: add_module(): You cannot add the same module/version combo more than once.
# 3: prepare_build(): This module/version has already been built on: ...
# 3: module_is_added_or_die(): The module/version combo: ... is not located in the DKMS tree.
# 4: global: Cannot specify more than one action.
# 4: distro_version(): System is missing os-release file.
# 4: read_conf(): Could not locate dkms.conf file.
# 4: have_one_kernel(): The action ... does not support multiple kernel version parameters on the command line.
# 4: module_is_broken_and_die(): ... is broken!
# 5: check_all_is_banned(): The action ... does not support the --all parameter.
# 5: prepare_build(): Patch ... as specified in dkms.conf contains '..' path component.
# 5: prepare_build(): Patch ... as specified in dkms.conf cannot be found in ...
# 5: install: This module/version combo is already installed for kernel ...
# 6: prepare_build(): Application of patch ... failed.
# 6: install: You cannot install a module onto a non-existant kernel.
# 6: install: Installation aborted.
# 6: install: Install Failed (depmod problems). Module rolled back to built state.
# 6: make_tarball(): Modules must already be in the built state before using mktarball.
# 6: make_tarball(): Failed to make tarball.
# 7: load_tarball(): No valid dkms.conf in dkms_source_tree or dkms_binaries_only.
# 7: actual_build(): Build of ... failed for: ...
# 8: load_tarball(): ... is already added!
# 8: global: You have specified both --binaries-only and --source-only.
# 8: read_conf_or_die(): Bad conf file.
# 8: prepare_build(): The directory $source_dir does not appear to have module source located within it.
# 9: add_source_tree(): ... must contain a dkms.conf file!
# 9: make_tarball(): Missing write permissions for ...
# 9: load_tarball(): Unable to install ... using rpm.
# 10: add_source_tree(): Malformed dkms.conf file. Cannot load source tree.
# 10: build: Bad return status for module build on kernel: ...
# 11: autoinstall: One or more modules failed to install during autoinstall.
# 12: setup_kernels_arches(): Could not determine architecture.
# 77: skipped due to BUILD_EXCLUSIVE
# 101: install: pre_install failed, aborting install.

I do not suggest that all these get unique codes, but we should probably group them in some way ...

While it's possible for different actions to use the same code for different things, one should be aware that it's possible for some actions to be chained (e.g. ldtarballs calls autoinstall, or you can add/build/install a module in a single command ...)

Then there is the "global" group with errors like

• dkms is in broken state (not all actions may detect this)
• insufficient permissions
• invalid/insufficient/conflicting command line parameters

For add/build/install/... there are

• some precondition failed (something missing that is needed by the action / something is already there that would be created by the action / ...)
• the action itself failed

For status I'm not sure what should sensibly encoded in the exit code, especially since that may operate on several modules and kernels at the same time.
https://bugs.debian.org/565990
Maybe it's better to implement some specific query actions that take 3/4 parameters: e.g. dkms is_installed -m <mod> -v <ver> -k <krnl> [-a <arch>], but I'm not yet sure what this would be used for.