git: sbin/hammer: Detect possible relinking of pfs by user

[Tomohiro Kusumi]

commit a7c8cfeffaecd107a8cfd45efa25e459b45327f2
Author: Tomohiro Kusumi <kusumi.tomohiro at gmail.com>
Date:   Wed Apr 1 05:26:19 2015 +0900

    sbin/hammer: Detect possible relinking of pfs by user
    
    - It is possible that a user rm pfs symlink and then relink the pfs.
      If the user happens to make the symlink to, for example,
      "./@@-1:00001" (has "./" before "@@-1:00001"), then getpfs() fails
      to properly parse the pfs id as it fails to sscanf the string.
      This commit checks if the symlink has "/" in the path, and if yes
      use a basename of it to get rid of unnecessary prefix to make it
      work properly.
    
      ==========
      example1 - using existing /sbin/hammer
    
      # mount | grep TEST
      TEST on /HAMMER (hammer, local)
      # pwd
      /HAMMER
      # hammer pfs-master test1 > /dev/null
      # ls -l ./test1
      lrwxr-xr-x  1 root  wheel  10 Apr  2 04:27 ./test1 -> @@-1:00001
      # ln -s ./@@-1:00001 test2
      # ls -l ./test2
      lrwxr-xr-x  1 root  wheel  12 Apr  2 04:28 ./test2 -> ./@@-1:00001
      # hammer pfs-destroy ./test2
      You have requested that PFS#1 () be destroyed
      <snip>
      Destroying PFS #1 () in  5 4 3 2 1.. starting destruction pass
      pfs-destroy of PFS#1 failed: Directory not empty
    
      ==========
      example2 - using this commit
    
      # mount | grep TEST
      TEST on /HAMMER (hammer, local)
      # pwd
      /HAMMER
      # hammer pfs-master test1 > /dev/null
      # ls -l ./test1
      lrwxr-xr-x  1 root  wheel  10 Apr  2 04:31 ./test1 -> @@-1:00001
      # ln -s ./@@-1:00001 test2
      # ls -l ./test2
      lrwxr-xr-x  1 root  wheel  12 Apr  2 04:31 ./test2 -> ./@@-1:00001
      # hammer pfs-destroy ./test2
      You have requested that PFS#1 () be destroyed
      <snip>
      Destroying PFS #1 () in  5 4 3 2 1.. starting destruction pass
      pfs-destroy of PFS#1 succeeded!
      # ls -l ./test*
      lrwxr-xr-x  1 root  wheel  10 Apr  2 04:31 ./test1 -> @@PFS00001
      # hammer pfs-status ./test1
      Cannot access PFS ./test1: No such file or directory

Summary of changes:
 sbin/hammer/cmd_pseudofs.c | 24 ++++++++++++++++++++++--
 1 file changed, 22 insertions(+), 2 deletions(-)

http://gitweb.dragonflybsd.org/dragonfly.git/commitdiff/a7c8cfeffaecd107a8cfd45efa25e459b45327f2


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