This is probably a stupid question, and probably directed to the wrong
list. Apologies in advance, but I'm stumped
I've been working on a kernel module to report on "changed files". It
works just fine -- I wrap the orignal system calls with my
replacements which queue the filenames being modified, and when
another proccess reads from the device or proc entry, they get a nice
snapshot of what's going on in the system -- except that all the paths
are relative to the calling process.
So, a little ignorance being a dangerous thing, I thought I'd be clever
and manually reconstruct the full path by walking up
current->fs->pwd->d_parent and padding d_name to the filename until it
hits root.
Unfortunatly, this approach causes kernel panics. e.g., the attached
code snippet will inevitably bring down the machine if I call it
during in my replacement open, mkdir, rmdir, unlink routines -- and
tehy all work fine without itq.
What am I not getting? I do see, before I go down, that there's a few
occasions where current() is NULL...
Apologies in advance for a wordy, probably stupid question, but I'm
stumped.
If this is not the right approach for what I'm trying to do (e.g. a
kernel space getcwd()), can someone point me to something else I can try?
Thanks in advance,
Mike Welles
----------------------------------------
(this is the greatly reduced version which does nothing but try and
reference current->fs->pwd)
void fill_full_path(char *name)
{
if (current==NULL)
{
#ifdef DEBUG
printk("ERROR! current == NULL\n");
#endif
return;
}
if (current->fs==NULL)
{
#ifdef DEBUG
printk("ERROR! current-> == NULL\n");
#endif
return;
}
if (current->fs->pwd==NULL)
{
#ifdef DEBUG
printk("ERROR! current->fs->pwd == NULL\n");
#endif
return;
}
return;
}
This is probably a stupid question: I've been working on a kernel
module to report on "changed files".
It works just fine -- I wrap the orignal system calls with my
replacements which queue the filenames being modified, and when
another proccess reads from the device or proc entry, they get a nice
snapshot of what's going on in the system -- except that all the paths
are relative to the calling process.
So, a little ignorance being a dangerous thing, I thought I'd be clever
and manually reconstruct the full path by walking up
current->fs->pwd->d_parent and padding d_name to the filename until it
hits root.
Unfortunatly, this approach causes kernel panics. e.g., the attached
code snippet will inevitably bring down the machine if I call it
during in my replacement open, mkdir, rmdir, unlink routines -- and
tehy all work fine without itq.
What am I not getting? I do see, before I go down, that there's a few
occasions where current() is NULL...
Apologies in advance for a wordy, probably stupid question, but I'm
stumped.
If this is not the right approach for what I'm trying to do (e.g. a
kernel space getcwd()), can someone point me to where I should look?
Thanks in advance,
Mike Welles
----------------------------------------
(this is the greatly reduced version which does nothing but try and
reference current->fs->pwd)
void fill_full_path(char *name)
{
if (current==NULL)
{
#ifdef DEBUG
printk("ERROR! current == NULL\n");
#endif
return;
}
if (current->fs==NULL)
{
#ifdef DEBUG
printk("ERROR! current-> == NULL\n");
#endif
return;
}
if (current->fs->pwd==NULL)
{
#ifdef DEBUG
printk("ERROR! current->fs->pwd == NULL\n");
#endif
return;
}
return;
}
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