Date: Thu, 15 Apr 2010 00:35:47 +0300 From: Kostik Belousov <kostikbel@gmail.com> To: John Baldwin <jhb@freebsd.org> Cc: freebsd-hackers@freebsd.org, Fernando Apestegu?a <fernando.apesteguia@gmail.com> Subject: Re: Understanding proc_rwmem Message-ID: <20100414213547.GY2415@deviant.kiev.zoral.com.ua> In-Reply-To: <201004141721.00254.jhb@freebsd.org> References: <x2l1bd550a01004141322m420065fbj742800c3e4a81927@mail.gmail.com> <201004141721.00254.jhb@freebsd.org>
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--yU7+DNvIsw2sWoF2 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Wed, Apr 14, 2010 at 05:21:00PM -0400, John Baldwin wrote: > On Wednesday 14 April 2010 4:22:56 pm Fernando Apestegu?a wrote: > > Hi all, > >=20 > > I'm trying to read process memory other than the current process in > > kernel. I was told to use the proc_rwmem function, however I can't get > > it working properly. At first, I'm trying to read how many elements > > the environment variables vector has. To do this I tried this from a > > linprocfs filler function: > >=20 > >=20 > > struct iovec iov; > > struct uio tmp_uio; > > struct ps_strings *pss; > > int ret_code; > >=20 > > buff =3D malloc(sizeof(struct ps_strings), M_TEMP, M_WAITOK); > > memset(buff, 0, sizeof(struct ps_strings)); > >=20 > > PROC_LOCK_ASSERT(td->td_proc, MA_NOTOWNED); > > iov.iov_base =3D (caddr_t) buff; > > iov.iov_len =3D sizeof(struct ps_strings); > > tmp_uio.uio_iov =3D &iov; > > tmp_uio.uio_iovcnt =3D 1; > > tmp_uio.uio_offset =3D (off_t)(p->p_sysent->sv_psstrings); > > tmp_uio.uio_resid =3D sizeof(struct ps_strings); > > tmp_uio.uio_segflg =3D UIO_USERSPACE; > > tmp_uio.uio_rw =3D UIO_READ; > > tmp_uio.uio_td =3D td; > > ret_code =3D proc_rwmem(td->td_proc, &tmp_uio); >=20 > I think you want to use 'p' instead of 'td->td_proc' here. As it is you = are=20 > reading from the current process instead of the target process I believe. And UIO_USERSPACE sound suspicious. Note that segment flag is for the requestor address space. --yU7+DNvIsw2sWoF2 Content-Type: application/pgp-signature Content-Disposition: inline -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.10 (FreeBSD) iEYEARECAAYFAkvGNTMACgkQC3+MBN1Mb4gxEACgq+kVWS7GxrzbgLDlTNgPl00K veAAn3/GlFs+mwAcrx1JQXs/2qKoeRSK =bUSc -----END PGP SIGNATURE----- --yU7+DNvIsw2sWoF2--
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