When the VirtualStore feature is in effect, it is safe to let random users write into C:\ProgramData because other users won't see those files. This seemed to be the case when we introduced support for C:\ProgramData\Git\config. However, when that feature is not in effect (which seems to be the case in newer Windows 10 versions), we'd rather not use those files unless they come from a trusted source, such as an administrator. This change imitates the strategy chosen by PowerShell's native OpenSSH port to Windows regarding host key files: if a system file is owned neither by an administrator, a system account, or the current user, it is ignored.
When initializing a repository, we need to check whether its working directory supports symlinks to correctly set the initial value of the "core.symlinks" config variable. The code to check the filesystem is reusable in other parts of our codebase, like for example in our tests to determine whether certain tests can be expected to succeed or not. Extract the code into a new function `git_path_supports_symlinks` to avoid duplicate implementations. Remove a duplicate implementation in the repo test helper code.
These checks are preformed by libgit2 on checkout, but they're also useful for performing checks in applications which do not involve checkout. Expose them under `sys/` as it's still fairly in the weeds even for this library.
Right now, there's quite a lot of different function calls to determine
whether a path component matches a specific name after normalization
from the filesystem. We have a function for each of {gitattributes,
gitmodules, gitignore} multiplicated with {generic, NTFS, HFS} checks.
In the long time, this is unmaintainable in case there are e.g. new
filesystems with specific semantics, blowing up the number of functions
we need to implement.
Replace all functions with a simple `git_path_is_gitfile` function,
which accepts an enum pointing out the filename that is to be checked
against as well as the filesystem normalizations to check for. This
greatly simplifies implementation at the expense of the caller having to
invoke a somewhat longer function call.
Any part of the library which asks the question can pass in the mode to have it checked against `.gitmodules` being a symlink. This is particularly relevant for adding entries to the index from the worktree and for checking out files.
We may take in names from the middle of a string so we want the caller to let us know how long the path component is that we should be checking.
These will be used by the checkout code to detect them for the particular filesystem they're on.
These can't go into the public API yet as we don't want to introduce API or ABI changes in a security release.
This function has previously been implemented in Windows-specific path handling code as `path__is_dirsep`. As we will need this functionality in other parts, extract the logic into "path.h" alongside with a non-Windows implementation.
This function has previously been implemented in Windows-specific path handling code as `path__is_absolute`. As we will need this functionality in other parts, extract the logic into "path.h" alongside with a non-Windows implementation.