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 Apesteguía wrote: > Hi all, > > 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: > > > struct iovec iov; > struct uio tmp_uio; > struct ps_strings *pss; > int ret_code; > > buff = malloc(sizeof(struct ps_strings), M_TEMP, M_WAITOK); > memset(buff, 0, sizeof(struct ps_strings)); > > PROC_LOCK_ASSERT(td->td_proc, MA_NOTOWNED); > iov.iov_base = (caddr_t) buff; > iov.iov_len = sizeof(struct ps_strings); > tmp_uio.uio_iov = &iov; > tmp_uio.uio_iovcnt = 1; > tmp_uio.uio_offset = (off_t)(p->p_sysent->sv_psstrings); > tmp_uio.uio_resid = sizeof(struct ps_strings); > tmp_uio.uio_segflg = UIO_USERSPACE; > tmp_uio.uio_rw = UIO_READ; > tmp_uio.uio_td = td; > ret_code = proc_rwmem(td->td_proc, &tmp_uio); I think you want to use 'p' instead of 'td->td_proc' here. As it is you are reading from the current process instead of the target process I believe. -- John Baldwin
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