Date: Wed, 14 Apr 2010 17:21:00 -0400 From: John Baldwin <jhb@freebsd.org> To: freebsd-hackers@freebsd.org Cc: Fernando =?iso-8859-1?q?Apestegu=EDa?= <fernando.apesteguia@gmail.com> Subject: Re: Understanding proc_rwmem Message-ID: <201004141721.00254.jhb@freebsd.org> In-Reply-To: <x2l1bd550a01004141322m420065fbj742800c3e4a81927@mail.gmail.com> References: <x2l1bd550a01004141322m420065fbj742800c3e4a81927@mail.gmail.com>
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On Wednesday 14 April 2010 4:22:56 pm Fernando Apestegu=EDa 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); I think you want to use 'p' instead of 'td->td_proc' here. As it is you ar= e=20 reading from the current process instead of the target process I believe. =2D-=20 John Baldwin
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