From: "Peter T. Breuer" <ptb@inv.it.uc3m.es>
To: linux kernel <linux-kernel@vger.kernel.org>
Subject: sysctl in 2.6.24.2 excludes unapproved files from /proc/sys?
Date: Sat, 1 Mar 2008 02:12:05 +0100 (CET) [thread overview]
Message-ID: <200803010112.m211C5h4027092@betty.it.uc3m.es> (raw)
A change in 2.6.24.x kernel/sysctl.c seems to exclude exo-kernel drivers
from using the /proc/sys/ interface:
@@ -1275,7 +1481,9 @@ static void sysctl_set_parent(struct ctl
static __init int sysctl_init(void)
{
+ int err;
sysctl_set_parent(NULL, root_table);
+ err = sysctl_check_table(root_table);
return 0;
}
and
@@ -1360,6 +1568,10 @@ struct ctl_table_header *register_sysctl
tmp->used = 0;
tmp->unregistering = NULL;
sysctl_set_parent(NULL, table);
+ if (sysctl_check_table(tmp->ctl_table)) {
+ kfree(tmp);
+ return NULL;
+ }
spin_lock(&sysctl_lock);
list_add_tail(&tmp->ctl_entry, &root_table_header.ctl_entry);
spin_unlock(&sysctl_lock);
and IT TURNS OUT THAT (sorry, did I scream?) sysctl_check_table can't
succeed on anything that's now not been hardwired into the core kernel
because of the new sysctl_check.c file which contains gazzilions of
explict tables aying what is supposed to be in there in excruciating
detail and which are consulted through sysctl_check_table and
sysctl_binary_lookup. E.g:
static struct trans_ctl_table trans_random_table[] = {
{ RANDOM_POOLSIZE, "poolsize" },
{ RANDOM_ENTROPY_COUNT, "entropy_avail" },
{ RANDOM_READ_THRESH, "read_wakeup_threshold" },
{ RANDOM_WRITE_THRESH, "write_wakeup_threshold" },
{ RANDOM_BOOT_ID, "boot_id" },
{ RANDOM_UUID, "uuid" },
{}
};
It appears to me, not that I am totally sure because of the lack of
comments, that every attempt to add a new direcotry in the tree with
a number that is not listed in the above mess fails through
sysctl_binary_lookup.sysctl_binary_lookup, and every attempt to add
a directory with CTL_UNNUMBERED instead fails if it has children because
the children cry about having an unnumbered parent. Every attempt to
add a directory usurping an existing number fails through some string
mismatch against the trans_.._tables on the dirnames in one of the
numerous lookup functions (forget which).
(somebody has really spent their holidays on this).
What's a person to do?
Peter
next reply other threads:[~2008-03-01 1:20 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-03-01 1:12 Peter T. Breuer [this message]
2008-03-01 1:46 ` sysctl in 2.6.24.2 excludes unapproved files from /proc/sys? Alexey Dobriyan
2008-03-01 2:22 ` Peter T. Breuer
2008-03-01 10:50 ` Alexey Dobriyan
2008-03-01 9:37 ` Peter T. Breuer
2008-03-01 2:57 ` Valdis.Kletnieks
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