From owner-freebsd-hackers@FreeBSD.ORG Thu Mar 28 21:18:28 2013 Return-Path: Delivered-To: freebsd-hackers@freebsd.org Received: from mx1.freebsd.org (mx1.FreeBSD.org [8.8.178.115]) by hub.freebsd.org (Postfix) with ESMTP id 9D255BBE; Thu, 28 Mar 2013 21:18:28 +0000 (UTC) (envelope-from to.my.trociny@gmail.com) Received: from mail-ee0-f52.google.com (mail-ee0-f52.google.com [74.125.83.52]) by mx1.freebsd.org (Postfix) with ESMTP id 8202933C; Thu, 28 Mar 2013 21:18:27 +0000 (UTC) Received: by mail-ee0-f52.google.com with SMTP id d17so1533285eek.11 for ; Thu, 28 Mar 2013 14:18:26 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=x-received:sender:date:from:to:cc:subject:message-id:references :mime-version:content-type:content-disposition:in-reply-to :user-agent; bh=984artyxhfQm7yYAfwXYIJqaxzIT1NO9oyT8TZ4uPyg=; b=QAaWU3tCKNVJ8bBFACAQMeyTW0HI39VVNh0w4RzNj8QB9QexB1F/9MItNjukTx6/cP 1GRN96ZmHZLqXoqNDAkcCeZt/A8mRKT2ppvspHaev8UeS3aJGSEviC9PDL0qIq2EsSYT 8h9PHKEQQIwZ+tCR/A/C+SKYeG6aZ69onBYun/snuXtFTB2INV6/KBoMFM/uzJfH52Vs l/FNaBbTu4wqBW2J/JlyzmZ5JUSFciKpuAU9nHIX1WiXnVlwUHwayoiVSd35TqK5kLHX rTZOIPfQ94u39rJLFn+iM+wCRuFJQugFs0IpfO278c1UmsIJuKEBJ/idUTVYyPv7Lz1d gX3Q== X-Received: by 10.14.0.73 with SMTP id 49mr407426eea.21.1364505506209; Thu, 28 Mar 2013 14:18:26 -0700 (PDT) Received: from localhost ([178.150.115.244]) by mx.google.com with ESMTPS id s3sm388518eem.4.2013.03.28.14.18.24 (version=TLSv1.2 cipher=RC4-SHA bits=128/128); Thu, 28 Mar 2013 14:18:25 -0700 (PDT) Sender: Mikolaj Golub Date: Thu, 28 Mar 2013 23:18:21 +0200 From: Mikolaj Golub To: Konstantin Belousov Subject: Re: libprocstat(3): retrieve process command line args and environment Message-ID: <20130328211820.GA6657@gmail.com> References: <20130212215054.GA9839@gmail.com> <201302200904.15324.jhb@freebsd.org> <20130220195801.GA8679@gmail.com> <20130316180915.GA91146@gmail.com> <20130316191605.GJ3794@kib.kiev.ua> <20130316223339.GA3534@gmail.com> <20130317063033.GL3794@kib.kiev.ua> <20130317091930.GA2833@gmail.com> <20130324155426.GA87022@gmail.com> <20130328105134.GO3794@kib.kiev.ua> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20130328105134.GO3794@kib.kiev.ua> User-Agent: Mutt/1.5.21 (2010-09-15) Cc: Stanislav Sedov , Attilio Rao , "Robert N. M. Watson" , freebsd-hackers@freebsd.org X-BeenThere: freebsd-hackers@freebsd.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: Technical Discussions relating to FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 28 Mar 2013 21:18:28 -0000 On Thu, Mar 28, 2013 at 12:51:34PM +0200, Konstantin Belousov wrote: > In the generic Elf 64bit draft specification I have, the notes sections > are specified to consists of entries, each of which is an array of 8-byte > words. I think we are right using the 8-byte alignment. I have impression many implementations use 4-byte alignment. E.g. in NetBSD: sys/kern/core_elf32.c: #define ELFROUNDSIZE 4 /* XXX Should it be sizeof(Elf_Word)? */ #define elfround(x) roundup((x), ELFROUNDSIZE) Also, we have inconsistency with imgactl_elf.c/parse_notes(), which uses 4-byte alignment: note = (const Elf_Note *)((const char *)(note + 1) + roundup2(note->n_namesz, sizeof(Elf32_Addr)) + roundup2(note->n_descsz, sizeof(Elf32_Addr))); I suppose there were no issues before, because accidentally the sizes of all notes we had were 8 bytes aligned. Now, when I add new notes it will break things. I don't have strong opinion, it will be ok for me to leave 8-byte alignment and fix issues, just want to have strong support here :-) BTW, looking at NetBSD code I see they set p_align in the note segement to ELFROUNDSIZE: /* Write out the PT_NOTE header. */ ws.psections->p_type = PT_NOTE; ws.psections->p_offset = notestart; ws.psections->p_vaddr = 0; ws.psections->p_paddr = 0; ws.psections->p_filesz = notesize; ws.psections->p_memsz = 0; ws.psections->p_flags = PF_R; ws.psections->p_align = ELFROUNDSIZE; while we set to 0: /* The note segement. */ phdr->p_type = PT_NOTE; phdr->p_offset = hdrsize; phdr->p_vaddr = 0; phdr->p_paddr = 0; phdr->p_filesz = notesz; phdr->p_memsz = 0; phdr->p_flags = 0; phdr->p_align = 0; Shouldn't we set it to alignment size too? Note also, they set "Segment is readable" flag. > > > > 4) In libprocstat I added new functions and placed them under already > > existent FBSD_1.3 version section in Symbol.map. > > > > Shouldn't I bump the version? Won't I need any additional care if I > > want to MFC the code to stable/9 and may be 8? > Version of what ? MFC does not require any additional actions, FBSD_1.3 > is the valid version namespace in 9 and 8. Ok. Now I see it was rather silly question :-). Thanks. For this and your other notes. -- Mikolaj Golub