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From: jrw@hropus.UUCP (Jim Webb)
Newsgroups: net.unix
Subject: Re: inodes
Message-ID: <742@hropus.UUCP>
Date: Sun, 19-Oct-86 12:19:42 EDT
Article-I.D.: hropus.742
Posted: Sun Oct 19 12:19:42 1986
Date-Received: Tue, 21-Oct-86 06:31:37 EDT
References: <47@andromeda.UUCP>
Organization: Bell Labs, Holmdel, NJ
Lines: 36
Keywords: Anything like getpwent() for i-nodes ?

> 	                        Is there any way to "get" an i-node into a C 
> program, the way getpwent gets passwd entries ?  Do I really have to
> open the device file and look for the i-list ?  

The stat(2) call yields a lot of info in the inode, but if you are
looking for block info, reading the inode is the only means of getting
it.  There is not a getinode() function, but it would be a very simple
function to write.

Under System V, the physical disk slice looks like this:

   block 0       block 1     block 2 ....       
+------------+------------+---------------------------+---------------
|  BOOT BLK  | SUPER BLK  | INODES....                |  DATA BLOCKS
+------------+------------+---------------------------+---------------

So, to grab the inode, all one has to do is to lseek past the
boot and super- blocks, and then, using the inode number, lseek into
the ilist and read out the inode:

		#include <sys/types.h>
		#include <sys/ino.h>
		#include <fcntl.h>

		int fd;
		ino_t inum;
		struct dinode ibuf;

		fd=open("/dev/rdsk/0s0",O_RDONLY);
		lseek(fd,1024+inum*sizeof(struct dinode),0);
		read(fd,ibuf,sizeof(struct dinode));

Then you can look at any of the inode info via ibuf.
-- 
Jim Webb             "Out of phase--get help"          ...!ihnp4!hropus!jrw
		"Use the Force, Read the Source"