Date: Sat, 21 Jan 2012 01:56:45 +0200 From: Kostik Belousov <kostikbel@gmail.com> To: Eitan Adler <lists@eitanadler.com> Cc: jilles@freebsd.org, FreeBSD Hackers <freebsd-hackers@freebsd.org>, Colin Percival <cperciva@freebsd.org> Subject: Re: dup3 syscall - atomic set O_CLOEXEC with dup2 Message-ID: <20120120235645.GP31224@deviant.kiev.zoral.com.ua> In-Reply-To: <CAF6rxg=Xbh--nL3pebj=ra%2B09K%2BWJYen2JPVDWwR14%2BifG-_iQ@mail.gmail.com> References: <CAF6rxg=EjkwFbXQt3i2Nnz6_dcZtdek-2YdqyZnAdVPxVaWR_Q@mail.gmail.com> <20120112100840.GV31224@deviant.kiev.zoral.com.ua> <CAF6rxgne7M9xBb-mM1xsjPy3r-O%2BO%2BMzuYrsweG849V83MX3mA@mail.gmail.com> <CAF6rxgn5uddFb4LOGb0E_OOpVMiFavOVHwnrKF7cFHb6tfrPjw@mail.gmail.com> <CAF6rxg=Xbh--nL3pebj=ra%2B09K%2BWJYen2JPVDWwR14%2BifG-_iQ@mail.gmail.com>
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On Fri, Jan 20, 2012 at 06:25:42PM -0500, Eitan Adler wrote:
> I figure this isn't wanted?
You silently ignored part of the notes that were provided, and keep
complete silence on the primary question about non-standard and fractional
nature of the patch.
I see no reason to retype my previous response.
>=20
> On Thu, Jan 12, 2012 at 10:07 PM, Eitan Adler <lists@eitanadler.com> wrot=
e:
> > Okay - here is version 2 (compile and run tested)
> >
> > Index: sys/kern/kern_descrip.c
> > =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D
> > --- sys/kern/kern_descrip.c =9A =9A (revision 229830)
> > +++ sys/kern/kern_descrip.c =9A =9A (working copy)
> > @@ -110,6 +110,7 @@
> > =9A/* Flags for do_dup() */
> > =9A#define DUP_FIXED =9A =9A =9A0x1 =9A =9A /* Force fixed allocation */
> > =9A#define DUP_FCNTL =9A =9A =9A0x2 =9A =9A /* fcntl()-style errors */
> > +#define DUP_CLOEXEC =9A =9A0x4 =9A =9A /* Enable O_CLOEXEC on the new =
fd */
> >
> > =9Astatic int do_dup(struct thread *td, int flags, int old, int new,
> > =9A =9A register_t *retval);
> > @@ -307,7 +308,36 @@
> > =9A =9A =9A =9Areturn (0);
> > =9A}
> >
> > +struct dup3_args {
> > + =9A =9A =9A u_int =9A from;
> > + =9A =9A =9A u_int =9A to;
> > + =9A =9A =9A int =9A =9A flags;
> > +};
> > +
> > =9A/*
> > + * Duplicate a file descriptor and allow for O_CLOEXEC
> > + */
> > +
> > +int
> > +sys_dup3(struct thread * td, struct dup3_args * uap) {
> > + =9A =9A =9A int dupflags;
> > +
> > + =9A =9A =9A if (uap->from =3D=3D uap->to)
> > + =9A =9A =9A =9A =9A =9A =9A return (EINVAL);
> > +
> > + =9A =9A =9A if (uap->flags & ~O_CLOEXEC)
> > + =9A =9A =9A =9A =9A =9A =9A return (EINVAL);
> > +
> > + =9A =9A =9A dupflags =3D DUP_FIXED;
> > + =9A =9A =9A if (uap->flags & O_CLOEXEC)
> > + =9A =9A =9A =9A =9A =9A =9A dupflags |=3D DUP_CLOEXEC;
> > +
> > + =9A =9A =9A return (do_dup(td, dupflags, (int)uap->from, (int)uap->to,
> > + =9A =9A =9A =9A =9A =9A =9A =9A =9A td->td_retval));
> > + =9A =9A =9A return (0);
> > +}
> > +
> > +/*
> > =9A* Duplicate a file descriptor to a particular value.
> > =9A*
> > =9A* Note: keep in mind that a potential race condition exists when clo=
sing
> > @@ -912,6 +942,9 @@
> > =9A =9A =9A =9A =9A =9A =9A =9Afdp->fd_lastfile =3D new;
> > =9A =9A =9A =9A*retval =3D new;
> >
> > + =9A =9A =9A if (flags & DUP_CLOEXEC)
> > + =9A =9A =9A =9A =9A =9A =9A fdp->fd_ofileflags[new] |=3D UF_EXCLOSE;
> > +
> > =9A =9A =9A =9A/*
> > =9A =9A =9A =9A * If we dup'd over a valid file, we now own the referen=
ce to it
> > =9A =9A =9A =9A * and must dispose of it using closef() semantics (as i=
f a
> > Index: sys/kern/syscalls.master
> > =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D
> > --- sys/kern/syscalls.master =9A =9A(revision 229830)
> > +++ sys/kern/syscalls.master =9A =9A(working copy)
> > @@ -951,5 +951,6 @@
> > =9A =9A =9A =9A =9A =9A =9A =9A =9A =9A =9A =9A =9A =9A =9A =9A =9A =9A=
off_t offset, off_t len); }
> > =9A531 =9A =9AAUE_NULL =9A =9A =9A =9ASTD =9A =9A { int posix_fadvise(i=
nt fd, off_t offset, \
> > =9A =9A =9A =9A =9A =9A =9A =9A =9A =9A =9A =9A =9A =9A =9A =9A =9A =9A=
off_t len, int advice); }
> > +532 =9A =9AAUE_NULL =9A =9A =9A =9ASTD =9A =9A { int dup3(u_int from, =
u_int to, int flags); }
> > =9A; Please copy any additions and changes to the following compatabili=
ty tables:
> > =9A; sys/compat/freebsd32/syscalls.master
> > Index: sys/compat/freebsd32/syscalls.master
> > =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D
> > --- sys/compat/freebsd32/syscalls.master =9A =9A =9A =9A(revision 22983=
0)
> > +++ sys/compat/freebsd32/syscalls.master =9A =9A =9A =9A(working copy)
> > @@ -997,3 +997,4 @@
> > =9A =9A =9A =9A =9A =9A =9A =9A =9A =9A =9A =9A =9A =9A =9A =9A =9A =9A=
uint32_t offset1, uint32_t offset2,\
> > =9A =9A =9A =9A =9A =9A =9A =9A =9A =9A =9A =9A =9A =9A =9A =9A =9A =9A=
uint32_t len1, uint32_t len2, \
> > =9A =9A =9A =9A =9A =9A =9A =9A =9A =9A =9A =9A =9A =9A =9A =9A =9A =9A=
int advice); }
> > +532 =9A =9AAUE_NULL =9A =9A =9A =9ASTD =9A =9A { int dup3(u_int from, =
u_int to, int flags); }
> >
> > Index: lib/libc/sys/Symbol.map
> > =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D
> > --- lib/libc/sys/Symbol.map =9A =9A (revision 229830)
> > +++ lib/libc/sys/Symbol.map =9A =9A (working copy)
> > @@ -383,6 +383,7 @@
> >
> > =9AFBSD_1.3 {
> > =9A =9A =9A =9Aposix_fadvise;
> > + =9A =9A =9A dup3;
> > =9A};
> >
> > =9AFBSDprivate_1.0 {
> >
> >
> > --
> > Eitan Adler
>=20
>=20
>=20
> --=20
> Eitan Adler
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