Was ist SYSCALL_DEFINE?

[berti]

Hallo,

was bedeutet SYSCALL_DEFINE in Kernel? Ich habe die folgende Pseudocode aus fs/super.c kopiert. Kann jemand bitte mir diesen Abschnitt erklären.

SYSCALL_DEFINE2(ustat, unsigned, dev, struct ustat __user *, ubuf)
{
struct super_block *s;
struct ustat tmp;
struct kstatfs sbuf;
int err = -EINVAL;

s = user_get_super(new_decode_dev(dev));
if (s == NULL)
goto out;
err = vfs_statfs(s->s_root, &sbuf);
drop_super(s);
if (err)
goto out;

memset(&tmp,0,sizeof(struct ustat));
tmp.f_tfree = sbuf.f_bfree;
tmp.f_tinode = sbuf.f_ffree;

err = copy_to_user(ubuf,&tmp,sizeof(struct ustat)) ? -EFAULT : 0;
out:
return err;
}


Danke im Voraus

[Irithori]

Bin kein Developer, aber damit die hier anwesenden Developer dich verstehen und evtl was dazu sagen können:

Please re-write your question in english

[berti]

Hello,

What does SYSCALL_DEFINE in kernel? I copied the following source code from fs/super.c. Can someone please explain to me this section.

SYSCALL_DEFINE2(ustat, unsigned, dev, struct ustat __user *, ubuf)
{
struct super_block *s;
struct ustat tmp;
struct kstatfs sbuf;
int err = -EINVAL;

s = user_get_super(new_decode_dev(dev));
if (s == NULL)
goto out;
err = vfs_statfs(s->s_root, &sbuf);
drop_super(s);
if (err)
goto out;

memset(&tmp,0,sizeof(struct ustat));
tmp.f_tfree = sbuf.f_bfree;
tmp.f_tinode = sbuf.f_ffree;

err = copy_to_user(ubuf,&tmp,sizeof(struct ustat)) ? -EFAULT : 0;
out:
return err;
}

Thank