shared: include root when canonicalizing conf paths

The conf_files_list family accepts an alternate root path to prefix all
directories in the list but path_strv_canonicalize_uniq doesn't use it.
This results in the suspicious behavior of resolving directory symlinks
based on the contents of / instead of the alternate root.

This adds a prefix argument to path_strv_canonicalize which will now
prepend the prefix, if given, to every path in the list. To avoid
answering what a relative path means when called with a root prefix
path_strv_canonicalize is now path_strv_canonicalize_absolute and only
considers absolute paths. Fortunately all users of already call
path_strv_canonicalize with a list of absolute paths.

1 files changed, 2 insertions, 2 deletions

diff --git a/src/shared/path-util.h b/src/shared/path-util.h
index 178bed5f17..2b8ea0260e 100644
--- a/src/shared/path-util.h
+++ b/src/shared/path-util.h
@@ -46,8 +46,8 @@ char* path_startswith(const char *path, const char *prefix) _pure_;
 bool path_equal(const char *a, const char *b) _pure_;
 
 char** path_strv_make_absolute_cwd(char **l);
-char** path_strv_canonicalize(char **l);
-char** path_strv_canonicalize_uniq(char **l);
+char** path_strv_canonicalize_absolute(char **l, const char *prefix);
+char** path_strv_canonicalize_absolute_uniq(char **l, const char *prefix);
 
 int path_is_mount_point(const char *path, bool allow_symlink);
 int path_is_read_only_fs(const char *path);