Linux fakeroot confusion

Question

I have lot of confusion over fakeroot utility. I am trying to add a character node to /dev folder to two rootfs. Owner for rootfs_1 is myself whereas owner of second is root.

1. rootfs_1 owner is Me.
   a. If I do ls -l. I see owner as "Me Me"
   b. I try to create a node using mknod in rootfs_1/dev and it fails.
   c. $fakeroot command goes through.
   d. ls -al. I see owner as root (Which I know is fake)
   e. Now I can create a node in rootfs_1/dev using mknod.
   f. exit
   g. Newly created node has owner as "Me" which I expected.

2. rootfs_2 owner is root
   a. ls -l. I see owner as "root root"
   b. I try to create a node using mknod in rootfs_2/dev and it fails.(expected)
   c. $fakeroot command goes through.
   d. Now I try to create a node and it fails.

Now, I know the behavior is expected. But I am confused about how fakeroot works and flow of system calls through fakeroot. I think fakeroot does LD_PRELOAD trick.

Can anyone explain little in detail why case 1 works and case 2 fails.

Thanks

Answer 1

All that fakeroot does is keep track of a "fake" owner for files that are modified while it's active. It doesn't simulate any other filesystem operations, such as file creation, so you still can't create files in a root-owned directory even with it active.