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sysctl: Introduce a generic compat sysctl sysctl

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This uses compat_alloc_userspace to remove the various
hacks to allow do_sysctl to write to throuh oldlenp.

The rest of our mature compat syscall helper facitilies
are used as well to ensure we have a nice clean maintainable
compat syscall that can be used on all architectures.

The motiviation for a generic compat sysctl (besides the
obvious hack removal) is to reduce the number of compat
sysctl defintions out there so I can refactor the
binary sysctl implementation.

ppc already used the name compat_sys_sysctl so I remove the
ppcs version here.

Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
This commit is contained in:
Eric W. Biederman 2009-04-03 00:36:27 -07:00
parent 2830b68361
commit da3f6f9b3e
2 changed files with 50 additions and 52 deletions
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50
kernel/sysctl_binary.c
View file

@ -176,3 +176,53 @@ SYSCALL_DEFINE1(sysctl, struct __sysctl_args __user *, args)
return error;
}
#ifdef CONFIG_COMPAT
#include <asm/compat.h>
struct compat_sysctl_args {
compat_uptr_t name;
int nlen;
compat_uptr_t oldval;
compat_uptr_t oldlenp;
compat_uptr_t newval;
compat_size_t newlen;
compat_ulong_t __unused[4];
};
asmlinkage long compat_sys_sysctl(struct compat_sysctl_args __user *args)
{
struct compat_sysctl_args tmp;
compat_size_t __user *compat_oldlenp;
size_t __user *oldlenp = NULL;
size_t oldlen = 0;
ssize_t result;
if (copy_from_user(&tmp, args, sizeof(tmp)))
return -EFAULT;
compat_oldlenp = compat_ptr(tmp.oldlenp);
if (compat_oldlenp) {
oldlenp = compat_alloc_user_space(sizeof(*compat_oldlenp));
if (get_user(oldlen, compat_oldlenp) ||
put_user(oldlen, oldlenp))
return -EFAULT;
}
lock_kernel();
result = do_sysctl(compat_ptr(tmp.name), tmp.nlen,
compat_ptr(tmp.oldval), oldlenp,
compat_ptr(tmp.newval), tmp.newlen);
unlock_kernel();
if (oldlenp && !result) {
if (get_user(oldlen, oldlenp) ||
put_user(oldlen, compat_oldlenp))
return -EFAULT;
}
return result;
}
#endif /* CONFIG_COMPAT */