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Diffstat (limited to 'doc/chroot')
| -rw-r--r-- | doc/chroot | 31 |
1 files changed, 31 insertions, 0 deletions
diff --git a/doc/chroot b/doc/chroot new file mode 100644 index 0000000..a0d1758 --- /dev/null +++ b/doc/chroot @@ -0,0 +1,31 @@ +Pseudo incorporates functionality similar to that of fakechroot. + +The implementation is basically as follows: When incoming arguments +are known to be paths, they are automatically converted to absolute, +fully canonicalized, paths. When the chroot(2) call is used, pseudo +intercepts it and stashes the path to the new root directory internally +in the client. This path is then silently prepended to absolute +paths. The internal tracking of file paths uses absolute paths +including the path to the chroot directory. So, all underlying calls +are invoked with absolute, canonical, paths. + +A few calls are then modified. For instance, when readlink() returns +a link, it strips a leading prefix looking like the chroot directory; +when symlink() creates a link, if the link path is absolute, the chroot +directory is prepended to it. + +This behavior, which may seem surprising, is an attempt to produce +path resolution equivalent to what would normally happen when +canonicalizing a path using real chroot; if you create a link to /tmp +while in a chroot environment, following that link should yield +<chroot>/tmp. Arguably, now that we are intercepting nearly every +incoming path, we should just prepend the chroot path when following +absolute symlinks -- this may get revisited. + +Similarly, when glob() is called, the path to be globbed has the +chroot directory prepended, and then the results have any leading +chroot directory stripped from them. + +This implementation is far from complete or perfect; the intent is +that it provide enough functionality to allow RPM and similar tools +to run file system installs using chroot(). |