11 Dec
2003
11 Dec
'03
4:18 p.m.
On Thu, Dec 11, 2003 at 09:15:50AM -0600, Jack O'Quin wrote:
I've been looking at that, and plan to do it next.
A good example is
always helpful. It can help to avoid missing some subtle detail,
especially important for kernel-mode programming.
Here is some of the boilerplate code we used. Also have code to make a proc
dir and use it, so instead of /proc/realtime or what not, you could have
/proc/realtime/a, /proc/realtime/b, etc. Also have code to do a read/write
proc file.
These are against linux-2.4. Haven't played with proc on 2.6, yet.
#include <linux/proc_fs.h>
#ifdef CONFIG_PROC_FS
static struct proc_dir_entry *proc_foo;
#endif
init(...)
{
...
#ifdef CONFIG_PROC_FS
proc_foo = create_proc_read_entry("foo", 0, NULL, foo_read_proc, NULL);
if (!proc_foo {
printk(KERN_ERR "can't create /proc/foo\n");
}
#endif
...
}
cleanup(...)
{
...
remove_proc_entry("foo", NULL);
...
}
#ifdef CONFIG_PROC_FS
static int
foo_read_proc(char *buf, char **start, off_t pos, int len, int *eof, void *x)
{
int plen;
plen = sprintf(buf, "%s\n", foo);
/* trying to read a bad offset? */
if (pos >= plen) {
*eof = 1;
return 0;
}
/* did we write everything we wanted to? */
if (len >= (plen-pos)) {
*eof = 1;
}
*start = buf + pos;
plen -= pos;
return (len > plen) ? plen : len;
}
#endif