Re: [Qemu-devel] [PATCH] uselib, mincore and readahead syscalls

["Kirill A. Shutemov" <kirill@shutemov.name>]

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On Fri, Sep 19, 2008 at 02:37:13PM +0300, Riku Voipio wrote:
> On Fri, Sep 19, 2008 at 11:05:35AM +0300, Kirill A. Shutemov wrote:
> > On Wed, Sep 17, 2008 at 10:45:42PM +0300, Riku Voipio wrote:
> > > These have been carried in Debian since forever. Added lock_user()
> > > calls for mincore before submitting, I'm not sure if that's the correct
> > > way?
> > > 
> > > Signed-off-by: Riku Voipio <riku.voipio@iki.fi>
> 
> > I think this patch should be splited by syscall.
> 
> Yes, but expecting that these patches as going to be ignored I didn't
> want to put too much effort in them..
> 
> > > Index: trunk/linux-user/syscall.c
> > > ===================================================================
> > > --- trunk.orig/linux-user/syscall.c	2008-09-17 20:07:40.000000000 +0300
> > > +++ trunk/linux-user/syscall.c	2008-09-17 21:43:47.000000000 +0300
> > > @@ -276,6 +276,7 @@
> > >  extern int setfsuid(int);
> > >  extern int setfsgid(int);
> > >  extern int setgroups(int, gid_t *);
> > > +extern int uselib(const char*);
> 
> > Probably, we should use _syscall1 macros instead.
> 
> Why? More specifically, in which cases should we use _syscall macros
> and which cases the libc versions? I don't see much logic in the current
> mix of both being used in syscall.c

Sorry. I'm wrong.

> 
> > >  #define ERRNO_TABLE_SIZE 1200
> > >  
> > > @@ -4226,7 +4227,13 @@
> > >  #endif
> > >  #ifdef TARGET_NR_uselib
> > >      case TARGET_NR_uselib:
> > > -        goto unimplemented;
> > > +		{
> > > +			if(!(p = lock_user_string(arg1)))
> > > +				goto efault;
> > > +        	ret = get_errno(uselib(path(p)));
> > > +			unlock_user(p, arg1, 0);
> > > +		}
> > > +        break;
> > >  #endif
> > >  #ifdef TARGET_NR_swapon
> > >      case TARGET_NR_swapon:
> > > @@ -5512,7 +5519,18 @@
> > >          goto unimplemented;
> > >  #ifdef TARGET_NR_mincore
> > >      case TARGET_NR_mincore:
> > > -        goto unimplemented;
> > > +		{
> > > +			void *a;
> > > +			if (!(a = lock_user(VERIFY_READ, arg1,arg2, 0)))
> > > +            	goto efault;
> > > +        	if (!(p = lock_user_string(arg3)))
> > > +            	goto mincore_fail;
> > > +        	ret = get_errno(mincore((void*)a, (size_t)arg2, (unsigned char*)p));
> > 
> > Type casting is unneeded here.
> 
> Will fix
> 
> > > +			unlock_user(p, arg3, ret);
> > > +			mincore_fail:
> > > +			unlock_user(a, arg1, 0);
> 
> > You should set ret here.
> 
> Will fix
> 
> > > +		}
> > > +        break;
> > >  #endif
> > >  #ifdef TARGET_NR_madvise
> > >      case TARGET_NR_madvise:
> > > @@ -5652,7 +5670,8 @@
> > >          break;
> > >  #ifdef TARGET_NR_readahead
> > >      case TARGET_NR_readahead:
> > > -        goto unimplemented;
> > > +        ret = get_errno(readahead((int)arg1, (off64_t)arg2, (size_t)arg3));
> > 
> > Type casting is unneeded here.
> 
> Will fix
> 
> > > +        break;
> > >  #endif
> > >  #ifdef TARGET_NR_setxattr
> > >      case TARGET_NR_setxattr:
> > 
> > -- 
> > Regards,  Kirill A. Shutemov
> >  + Belarus, Minsk
> >  + ALT Linux Team, http://www.altlinux.com/
> 
> 
> 
> -- 
> "rm -rf" only sounds scary if you don't have backups
> 
> 

-- 
Regards,  Kirill A. Shutemov
 + Belarus, Minsk
 + ALT Linux Team, http://www.altlinux.com/

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