On Sat, 29 Jul 2000, Rahul Shrivastava wrote:
> hi all,
> I am a newcomer to the world of linux. I have few queries which i guess u
> could explain.
>
> 1) how does the kernel maintain the cwd for a process ?
> 2) how is the 'cd' command implemented in the kernel?
> 3) which are the related files ?
cd is a built-in shell command. The syscall used to change directory is
chdir (fchdir). You can find sys_chdir in fs/open.c.
This bit sets the cwd (pwd) to the 'dentry' corresponding to the filename
given as argument to sys_chdir.
/* exchange dentries */
tmp = current->fs->pwd;
current->fs->pwd = dentry;
dentry = tmp;
current is a 'struct task_struct' and you can find it in
include/linux/sched.h
Links to various documents on the kernel:
http://jungla.dit.upm.es/~jmseyas/linux/kernel/hackers-docs.html
What is a dentry? you ask. Try
http://www.atnf.csiro.au/~rgooch/linux/vfs.txt
And you may also want to check out
http://www.kernelnewbies.org/
/Urban
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