On Thu, Apr 23, 2015 at 11:22:49AM -0400, Tejun Heo wrote:
> Hello,
>
> On Wed, Apr 22, 2015 at 02:55:06PM -0700, Luis R. Rodriguez wrote:
> > +int param_set_bool_enable_only(const char *val, const struct kernel_param
> > *kp)
> > +{
> > + int err = 0;
> > + bool new_value;
> > + bool orig_value = *(bool *)kp->arg;
> > + struct kernel_param dummy_kp = *kp;
> > +
> > + dummy_kp.arg = &new_value;
> > +
> > + err = param_set_bool(val, &dummy_kp);
> > + if (err)
> > + return err;
> > +
> > + /* Don't let them unset it once it's set! */
> > + if (!new_value && orig_value)
> > + return -EROFS;
>
> I know that this was moved from another place but as we're making it
> generic now I'm a bit curious about -EROFS. Wouldn't -EINVAL be a
> more conventional choice here?
Let's see, I tested to see what errors we get:
Userspace:
-EROFS:
mcgrof@ergon ~/devel/test-sig-force-general $ sudo insmod ./hello.ko
test_sig_enforce=1
insmod: ERROR: could not insert module ./hello.ko: Read-only file system
-EINVAL:
mcgrof@ergon ~/devel/test-sig-force-general $ sudo insmod ./hello.ko
test_sig_enforce=1
insmod: ERROR: could not insert module ./hello.ko: Invalid parameters
Kernel space:
Both of these returns yield this on the kernel ring buffer:
mcgrof@ergon ~/devel/test-sig-force-general $ sudo dmesg -c
[124677.202875] hello: `1' invalid for parameter `test_sig_enforce'
Alternative candidates:
#define EBADRQC 56 /* Invalid request code */
#define EOPNOTSUPP 95 /* Operation not supported on transport
endpoint */
Perhaps EOPNOTSUPP is best?
Luis
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