Messages in this thread | | | Date | Thu, 18 May 2006 19:45:01 -0700 | From | "Randy.Dunlap" <> | Subject | Re: [PATCH 4/9] namespaces: utsname: switch to using uts namespaces |
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On Thu, 18 May 2006 21:21:14 -0500 Serge E. Hallyn wrote:
> Quoting Randy.Dunlap (rdunlap@xenotime.net): > > > --- a/arch/i386/kernel/sys_i386.c > > > +++ b/arch/i386/kernel/sys_i386.c > > > @@ -210,7 +210,7 @@ asmlinkage int sys_uname(struct old_utsn > > > if (!name) > > > return -EFAULT; > > > down_read(&uts_sem); > > > - err=copy_to_user(name, &system_utsname, sizeof (*name)); > > > + err=copy_to_user(name, utsname(), sizeof (*name)); > > > > It would be really nice if you would fix spacing while you are here, > > like a space a each side of '='. > > > > and a space after ',' in the function calls below. > > Ok. Then in blocks like the following: > > > > - error = __copy_to_user(&name->sysname,&system_utsname.sysname,__OLD_UTS_LEN); > > > + error = __copy_to_user(&name->sysname,&utsname()->sysname,__OLD_UTS_LEN); > > > error |= __put_user(0,name->sysname+__OLD_UTS_LEN); > > > - error |= __copy_to_user(&name->nodename,&system_utsname.nodename,__OLD_UTS_LEN); > > > + error |= __copy_to_user(&name->nodename,&utsname()->nodename,__OLD_UTS_LEN); > > > error |= __put_user(0,name->nodename+__OLD_UTS_LEN); > > > - error |= __copy_to_user(&name->release,&system_utsname.release,__OLD_UTS_LEN); > > > + error |= __copy_to_user(&name->release,&utsname()->release,__OLD_UTS_LEN); > > > error |= __put_user(0,name->release+__OLD_UTS_LEN); > > > - error |= __copy_to_user(&name->version,&system_utsname.version,__OLD_UTS_LEN); > > > + error |= __copy_to_user(&name->version,&utsname()->version,__OLD_UTS_LEN); > > > error |= __put_user(0,name->version+__OLD_UTS_LEN); > > > - error |= __copy_to_user(&name->machine,&system_utsname.machine,__OLD_UTS_LEN); > > > + error |= __copy_to_user(&name->machine,&utsname()->machine,__OLD_UTS_LEN); > > > error |= __put_user(0,name->machine+__OLD_UTS_LEN); > > Should I leave it as is, to keep the consistent look? Change just the > lines I'm editing, making it inconsistent? Or change the whole block, > making my patch seem a bit larger than it really is, but giving the > nicest end result?
I'd go for the latter, along with my other comment of breaking them to fit into 80 columns also.
> I suppose I could insert a separate patchset fixing up the spacing in > those blocks but making no real changes at all, then apply my patch on > top of that...? > > > > --- a/arch/mips/kernel/syscall.c > > > +++ b/arch/mips/kernel/syscall.c > > > @@ -232,7 +232,7 @@ out: > > > */ > > > asmlinkage int sys_uname(struct old_utsname __user * name) > > > { > > > - if (name && !copy_to_user(name, &system_utsname, sizeof (*name))) > > > + if (name && !copy_to_user(name, utsname(), sizeof (*name))) > > > > > > OK, here's my big comment/question. I want to see <nodename> increased to > > 256 bytes (per current POSIX), so each field of struct <variant>_utsname > > needs be copied individually (I think) instead of doing a single > > struct copy. > > > > I've been working on this for the past few weeks (among other > > things). Sorry about the timing. > > I could send patches for this against mainline in a few days, > > but I'll be glad to listen to how it would be easiest for all of us > > to handle. > > > > I'm probably a little over half done with my patches. > > They will end up adding a lib/utsname.c that has functions for: > > put_oldold_unmame() // to user > > put_old_uname() // to user > > put_new_uname() // to user > > put_posix_uname() // to user > > Ok, so long as these functions accept a utsname, we should be able to > just change what we pass in to these functions to being the namespace's > utsname, right? Or am I missing the really nasty part?
The nodename field changes from 65 chars (struct new_utsname) to 256 chars (struct posix_utsname), and nodename is not the final field in the struct, so it's no longer safe to do a simple struct copy. Each field in the struct needs to be copied individually if the target is not a struct posix_utsname. It's not rocket science.
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