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Performance test I did the changes in the inode structure and the project is working fine thanks to monkeyboy. Now I wanted to know whether the changes affects the performance of memory read and write. I am using a application called iozone ( http://www.iozone.org ). Iozone gives numerous tests...

Solved Thank you jake_t for replying to my thread. I had already figured out how to do this: the same way you are telling. That is by the cr_ruid field of curthread defined in </usr/src/sys/sys/pcpu.h>. The only thing was, I knew there was a current pointer in Linux, but we didn't know what was...

As far as I know, ucred family of functions is used to manage user credential structures (struct ucred) within kernel. I saw /usr/src/sys/sys/ucred.h file struct ucred { u_int cr_ref; /* reference count */ #define cr_startcopy cr_uid uid_t cr_uid; /* effective user id */ uid_t cr_ruid...

I would like to know more about the ucred structure used in FreeBSD kernel for managing user credentials in kernel. I want to know how can use to get the user ID and also from the structure gets its data. Thanking in anticipation.

I basically want something that will work like printf but for a kernel module. Because I think printf won't work in kernel module.

Is it possible for me to print on the console from a kernel module using uprintf?

What changes do I need to make to the config file?

I want to make some changes to the ufs.ko module in the kernel. I made those changes in the required code and used the Makefile present at /usr/src/modules/ufs to compile the code. I got a ufs.ko. But when I replace this newly compiled ufs.ko with the old one present at /boot/kernel and reboot...

Can anyone please suggest me any books for learning kernel development especially for FreeBSD kernel development. Thank you

Monkey Boy I found out why the error was coming up. Thanks

Thank you once again MonkeyBoy Sir, I changed the struct stat in sys/stat.h by adding a field st_muid in place of the st_lspare and tried to refer this field from ls.c. But while compiling ls it fires a error 'struct stat' has no member st_muid I am really not able to understand the reason for...

Guys I am trying to remotely debug my FreeBSD machine using gdb. For this I have complied the GENERIC kernel with following debugging options: OPTIONS gdb OPTIONS ddb Then I have complied my kernel using following commands #cd /usr/src/sys/i386/conf #cp GENERIC DBGKERN #cd /usr/src #make...

Thank you for your reply monkeyboy. I have decided to go with your suggestion. I am now stuck as to how is VFS actually triggered in the file system. I read vfs_syscalls.c , vfs_nops.c as well as vfs_ops.c etc. Now the real puzzle for me is that, for the actual inode and the dinode structures...

Thank you for the reply. Well I am a beginner at UNIX and I am trying to make this project as my undergraduate project. I appreciate all the queries you listed above although I am half way through with studying the system calls. I think the path for the system calls are two fold: 1...

I'm trying to find how the information is retrieved from dinode and printed on the console or to the file. Once I know how it is retrieved, I'll try to add a field to dinode structure last_modified_by i.e it would have the username who lastly modified that file. I'll probably try to modify ls.c...

As of now we have understood that any program uses struct stat structure to store temporary inode info and display it. The struct stat structure gets info from struct inode (defined in inode.h) which in turn gets info from struct dinode. The struct dinode is (or may be, I am not sure) is the...

Thanks for the info. Can you also tell me: if I add the field to the inode structure which changes have to be made so that 1. All the metadata is consistent for all the files on the system 2. The functions that access the inodes of all the files and make modifications to it work the same way as...

Hi guys, I am stuck to a very specific problem. I want to add a field to the existing inode data structure, but I am not sure where to make the changes. What I want to know is where and how to make changes to the inode data structure. Also please explain the problems that may arise in making...