Specify the inode of a file?


 
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Operating Systems Solaris Specify the inode of a file?
# 1  
Old 03-25-2014
Specify the inode of a file?

Is there any way to create a file on Solaris 10 (ZFS preferably, but UFS would be helpful as well) with a specific inode number? I need to create a file with a large inode, greater than a 32bit integer.

I am trying to test a piece of software which may be incorrectly truncating large inodes down to 32-bit numbers.
# 2  
Old 03-25-2014
How is the application getting the inode of a file? Is it done through stat system call?
# 3  
Old 03-25-2014
Quote:
Originally Posted by bartus11
How is the application getting the inode of a file? Is it done through stat system call?
I'm not sure, I don't work with any of the code unfortunately.
# 4  
Old 03-25-2014
Put this into "fake_inode.d":
Code:
syscall::stat64:entry, syscall::lstat64:entry
/strstr(copyinstr(arg0), "passwd") != NULL/
{
  self->statptr = arg1;
}

syscall::stat64:return, syscall::lstat64:return
/self->statptr != NULL && curpsinfo->pr_dmodel == PR_MODEL_ILP32/
{
  self->st64_32 = (struct stat64_32 *)copyin(self->statptr, sizeof(struct stat64_32));
  self->st64_32->st_ino = 100000000000;
  copyout(self->st64_32, self->statptr, sizeof(struct stat64_32));
}

syscall::stat64:return, syscall::lstat64:return
/self->statptr != NULL && curpsinfo->pr_dmodel == PR_MODEL_LP64/
{
  self->st64 = (struct stat64 *)copyin(self->statptr, sizeof(struct stat64));
  self->st64->st_ino = 100000000000;
  copyout(self->st64, self->statptr, sizeof(struct stat64));
}

Replace "passwd" with whatever filename you want to fake inode for. Then run:
Code:
dtrace -w -s fake_inode.d

In the other terminal run:
Code:
ls -li /etc/passwd

Change the filename of the file that you are checking with "ls", if you changed the filename in the "fake_inode.d" script. This should produce:
Code:
# ls -li /etc/passwd
100000000000 -rw-r--r--   1 root     sys         1972 Jun 13  2013 /etc/passwd

These 4 Users Gave Thanks to bartus11 For This Post:
# 5  
Old 03-25-2014
Quote:
Originally Posted by bartus11
Put this into "fake_inode.d":

Replace "passwd" with whatever filename you want to fake inode for. Then run:

In the other terminal run:

Change the filename of the file that you are checking with "ls", if you changed the filename in the "fake_inode.d" script. This should produce:
Thank you. I changed the filename to "passwd2" because I wasn't sure what impact this would have on my /etc/passwd file.

Was I supposed to run fake_inode.d from within /etc? I created fake_inode.d and passwd2 inside /data, and ran the script from there. It has been saying this for a while:
Code:
[root@sol10: /data]# dtrace -w -s fake_inode.d
dtrace: script 'fake_inode.d' matched 6 probes
dtrace: allowing destructive actions

# 6  
Old 03-25-2014
Quote:
Originally Posted by unblockable
I changed the filename to "passwd2" because I wasn't sure what impact this would have on my /etc/passwd file.
The dtrace script has hopefully no impact in the target file.
Quote:
Was I supposed to run fake_inode.d from within /etc?
From anywhere you like.
Quote:
I created fake_inode.d and passwd2 inside /data, and ran the script from there. It has been saying this for a while:
Code:
[root@sol10: /data]# dtrace -w -s fake_inode.d
dtrace: script 'fake_inode.d' matched 6 probes
dtrace: allowing destructive actions

This is the expected output. You should leave the script running for the inode renumbering hack to persist.
As Bartus11 already stated, just use another terminal to experiment with you program expecting a large inode number.
This User Gave Thanks to jlliagre For This Post:
# 7  
Old 03-25-2014
Quote:
Originally Posted by jlliagre
The dtrace script has hopefully no impact in the target file.
From anywhere you like.

This is the expected output. You should leave the script running for the inode renumbering hack to persist.
As Bartus11 already stated, just use another terminal to experiment with you program expecting a large inode number.
Thank you for the clarification!

It looks like when I run
Code:
ls -li

it shows the real inode, but
Code:
ls -li <filename>

is showing the fake (large) inode:
Code:
[root@sol10: /data/xx]# ls -li
total 770488
  52000532 -rw-r--r--   1 root     root           0 Mar 24 10:52 asdf
  68687063 -rw-r--r--   1 root     root           0 Mar 25 17:18 passwd2

[root@sol10: /data/xx]# ls -li /data/xx/passwd2
100000000000 -rw-r--r--   1 root     root           0 Mar 25 17:18 /data/xx/passwd2

Smilie
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