Date: Fri, 24 Jan 2014 20:12:46 +0200 From: Konstantin Belousov <kostikbel@gmail.com> To: Bob Bishop <rb@gid.co.uk> Cc: Gennady Proskurin <gpr@mail.ru>, mdf@freebsd.org, standards@freebsd.org, jhb@freebsd.org Subject: Re: standards/186028: incorrect return values for posix_fallocate() Message-ID: <20140124181246.GO24664@kib.kiev.ua> In-Reply-To: <F5BBA557-7ACA-4A7A-9245-165CF962922D@gid.co.uk> References: <201401230858.s0N8wwQB039907@oldred.freebsd.org> <20140123094017.GH24664@kib.kiev.ua> <F5BBA557-7ACA-4A7A-9245-165CF962922D@gid.co.uk>
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On Thu, Jan 23, 2014 at 09:20:11PM +0000, Bob Bishop wrote:
> Hi,
>=20
> On 23 Jan 2014, at 09:40, Konstantin Belousov <kostikbel@gmail.com> wrote:
>=20
> > On Thu, Jan 23, 2014 at 08:58:58AM +0000, Gennady Proskurin wrote:
> >>=20
> >>> Number: 186028
> >>> Category: standards
> >>> Synopsis: incorrect return values for posix_fallocate()
> >>> Confidential: no
> >>> Severity: non-critical
> >>> Priority: low
> >>> Responsible: freebsd-standards
> >>> State: open
> >>> Quarter: =20
> >>> Keywords: =20
> >>> Date-Required:
> >>> Class: sw-bug
> >>> Submitter-Id: current-users
> >>> Arrival-Date: Thu Jan 23 09:00:00 UTC 2014
> >>> Closed-Date:
> >>> Last-Modified:
> >>> Originator: Gennady Proskurin
> >>> Release: FreeBSD 11.0-CURRENT
> >>> Organization:
> >>> Environment:
> >> FreeBSD gpr.nnz-home.ru 11.0-CURRENT FreeBSD 11.0-CURRENT #0 r260472+7=
43aa78(svn_head): Fri Jan 10 05:28:05 MSK 2014 gpr@gpr.nnz-home.ru:/usr=
/obj/usr/src/freebsd-head/sys/GPR amd64
> >>> Description:
> >> In case of error, posix_fallocate() should return error code itself, b=
ut in FreeBSD it returns -1 and sets errno.
>=20
> FWIW at least posix_madvise() and posix_fadvise() have the same problem.
Indeed, I suppose the following should also fix two syscalls noted.
I hope that some doc committer would do the pass over man pages
following Bruce' suggestions.
diff --git a/lib/libc/gen/pmadvise.c b/lib/libc/gen/pmadvise.c
index 60cef63..68b1181 100644
--- a/lib/libc/gen/pmadvise.c
+++ b/lib/libc/gen/pmadvise.c
@@ -12,5 +12,14 @@ __FBSDID("$FreeBSD$");
int
posix_madvise(void *address, size_t size, int how)
{
- return madvise(address, size, how);
+ int ret, saved_errno;
+
+ saved_errno =3D errno;
+ if (madvise(address, size, how) =3D=3D -1) {
+ ret =3D errno;
+ errno =3D saved_errno;
+ } else {
+ ret =3D 0;
+ }
+ return (ret);
}
diff --git a/lib/libc/sys/madvise.2 b/lib/libc/sys/madvise.2
index b5ea6b2..755ecc2 100644
--- a/lib/libc/sys/madvise.2
+++ b/lib/libc/sys/madvise.2
@@ -50,7 +50,10 @@ allows a process that has knowledge of its memory behavi=
or
to describe it to the system.
The
.Fn posix_madvise
-interface is identical and is provided for standards conformance.
+interface is identical, except it returns an error number on error and does
+not modify
+.Va errno ,
+and is provided for standards conformance.
.Pp
The known behaviors are:
.Bl -tag -width MADV_SEQUENTIAL
diff --git a/lib/libc/sys/posix_fadvise.2 b/lib/libc/sys/posix_fadvise.2
index 7a9a648..96c99d2 100644
--- a/lib/libc/sys/posix_fadvise.2
+++ b/lib/libc/sys/posix_fadvise.2
@@ -93,7 +93,7 @@ Future access to this data may require a read operation.
.Sh ERRORS
The
.Fn posix_fadvise
-system call will fail if:
+system call returns zero on success, and an error on failure:
.Bl -tag -width Er
.It Bq Er EBADF
The
diff --git a/lib/libc/sys/posix_fallocate.2 b/lib/libc/sys/posix_fallocate.2
index 1460764..7501777 100644
--- a/lib/libc/sys/posix_fallocate.2
+++ b/lib/libc/sys/posix_fallocate.2
@@ -83,9 +83,8 @@ that reduces the file size to a size smaller than
If successful,
.Fn posix_fallocate
returns zero.
-It returns error number on failure, without setting
-.Va errno
-variable.
+It returns an error on failure, without setting
+.Va errno .
.Sh ERRORS
Possible failure conditions:
.Bl -tag -width Er
diff --git a/sys/compat/freebsd32/freebsd32_misc.c b/sys/compat/freebsd32/f=
reebsd32_misc.c
index e4ffbe4..c7b677f 100644
--- a/sys/compat/freebsd32/freebsd32_misc.c
+++ b/sys/compat/freebsd32/freebsd32_misc.c
@@ -3005,8 +3005,10 @@ freebsd32_posix_fadvise(struct thread *td,
struct freebsd32_posix_fadvise_args *uap)
{
=20
- return (kern_posix_fadvise(td, uap->fd, PAIR32TO64(off_t, uap->offset),
- PAIR32TO64(off_t, uap->len), uap->advice));
+ td->td_retval[0] =3D kern_posix_fadvise(td, uap->fd,
+ PAIR32TO64(off_t, uap->offset), PAIR32TO64(off_t, uap->len),
+ uap->advice);
+ return (0);
}
=20
int
diff --git a/sys/kern/vfs_syscalls.c b/sys/kern/vfs_syscalls.c
index b864c90..4be9738 100644
--- a/sys/kern/vfs_syscalls.c
+++ b/sys/kern/vfs_syscalls.c
@@ -4725,6 +4725,7 @@ int
sys_posix_fadvise(struct thread *td, struct posix_fadvise_args *uap)
{
=20
- return (kern_posix_fadvise(td, uap->fd, uap->offset, uap->len,
- uap->advice));
+ td->td_retval[0] =3D kern_posix_fadvise(td, uap->fd, uap->offset,
+ uap->len, uap->advice);
+ return (0);
}
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