readdir within kernel

readdir within kernel

[Herbert Poetzl]

hi all!

I would like to know if this is the right way to
read a directory contents for a given directory
dentry within a kernel module ...

suggestions and/or hints are very welcome ...


extern	filldir_t xxx_filler;


void	xxx_dump_dir(struct dentry *de)
{
    	struct file pf;
	struct inode *in = de->d_inode;
	int ret;	
		
	ret = init_private_file(&pf, de, FMODE_READ);
	if (!pf.f_op->readdir)
		goto out_close;
		
    	ret = vfs_readdir(&pf, xxx_filler, (void *)0);

out_close:
	if (pf.f_op->release)
		pf.f_op->release(in, &pf);
    	return;
}

many thanks,
Herbert

Re: readdir within kernel

[Matthew Wilcox]

On Thu, Dec 19, 2002 at 06:06:32AM +0100, Herbert Poetzl wrote:
> I would like to know if this is the right way to
> read a directory contents for a given directory
> dentry within a kernel module ...

well, you probably _shouldn't_ be anyway... but since you are, this is
how I did it for debugging why my system couldn't find /sbin/init.

diff -u -p -r1.11 main.c
--- init/main.c 10 Dec 2002 22:03:28 -0000      1.11
+++ init/main.c 19 Dec 2002 13:08:45 -0000
@@ -501,6 +501,26 @@ static void do_pre_smp_initcalls(void)
 
 extern void prepare_namespace(void);
 
+static int kernel_filler(void *buf, const char *name, int namlen, loff_t offset,
+                       ino_t ino, unsigned int d_type)
+{
+       printk("%.*s\n", namlen, name);
+}
+
+static void kernel_ls(char *name)
+{
+       struct file *file;
+
+       file = filp_open(name, O_RDONLY, 0);
+       if (!file) {
+               printk("Could not open %s\n", name);
+               return;
+       }
+
+       vfs_readdir(file, kernel_filler, NULL);
+       filp_close(file, current->files);
+}
+
 static int init(void * unused)
 {
        static char * argv_sh[] = { "sh", NULL, };
@@ -540,6 +560,9 @@ static int init(void * unused)
 
        (void) dup(0);
        (void) dup(0);
+
+       kernel_ls("/");
+       kernel_ls("/sbin");
        
        /*
         * We try each of these until one succeeds.


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