This document describes how macOS software integrates with Chromium Updater for software updates.
macOS software updates are delivered as archives (often DMG or ZIP) that contain an .install executable at the root of the archive. (Typically the archives also contain an app bundle, i.e. the new version of the app.)
The updater will execute .install, passing data as positional command-line arguments and environment variables.
The archive may also contain .preinstall and .postinstall, which are executed before and after .install respectively. If any fail (exit with a non-zero status), the remaining executables are not run. Collectively, these three executables are called the “install executables”.
The install executables are passed the following arguments, in this order:
The absolute path to the unpacked update archive (i.e. the parent directory of the install executable.)
The absolute path to the installation of the app, based on its existence-checker value.
The install executables are executed in an environment with the following environment variables defined:
PATH: ‘/bin:/usr/bin:/Path/To/ksadmin’.KS_TICKET_XC_PATH: The absolute path to the installation of the app, based on its existence-checker value.KS_TICKET_AP: The ap value of the currently-installed version of the app. (Note: “ap” was called “tag” in Keystone.)If the install executables succeed, the updater will automatically record the new version of the application without any special action from the installers.
If the installers must also change other elements of the installation, such as the brand, path, ap, or similar, they may do so by executing ksadmin, for example by running ksadmin --register --product-id com.google.MyProductId --tag MyNewAp.