From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 329 invoked by alias); 17 Jul 2014 16:35:23 -0000 Mailing-List: contact gdb-patches-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: gdb-patches-owner@sourceware.org Received: (qmail 32568 invoked by uid 89); 17 Jul 2014 16:35:20 -0000 Authentication-Results: sourceware.org; auth=none X-Virus-Found: No X-Spam-SWARE-Status: No, score=-1.9 required=5.0 tests=AWL,BAYES_00,RP_MATCHES_RCVD,SPF_HELO_PASS,SPF_PASS autolearn=ham version=3.3.2 X-HELO: mx1.redhat.com Received: from mx1.redhat.com (HELO mx1.redhat.com) (209.132.183.28) by sourceware.org (qpsmtpd/0.93/v0.84-503-g423c35a) with (AES256-GCM-SHA384 encrypted) ESMTPS; Thu, 17 Jul 2014 16:35:18 +0000 Received: from int-mx11.intmail.prod.int.phx2.redhat.com (int-mx11.intmail.prod.int.phx2.redhat.com [10.5.11.24]) by mx1.redhat.com (8.14.4/8.14.4) with ESMTP id s6HGZDxg023990 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Thu, 17 Jul 2014 12:35:14 -0400 Received: from [127.0.0.1] (ovpn01.gateway.prod.ext.ams2.redhat.com [10.39.146.11]) by int-mx11.intmail.prod.int.phx2.redhat.com (8.14.4/8.14.4) with ESMTP id s6HGZBnK003801; Thu, 17 Jul 2014 12:35:11 -0400 Message-ID: <53C7FB3E.5010402@redhat.com> Date: Thu, 17 Jul 2014 16:40:00 -0000 From: Pedro Alves User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:24.0) Gecko/20100101 Thunderbird/24.6.0 MIME-Version: 1.0 To: Gary Benson , gdb-patches@sourceware.org CC: Tom Tromey , Doug Evans Subject: Re: [PATCH 02/15 v2] Remove some GDBSERVER checks from linux-ptrace References: <1405520243-17282-1-git-send-email-gbenson@redhat.com> <1405520243-17282-3-git-send-email-gbenson@redhat.com> In-Reply-To: <1405520243-17282-3-git-send-email-gbenson@redhat.com> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit X-SW-Source: 2014-07/txt/msg00474.txt.bz2 On 07/16/2014 03:17 PM, Gary Benson wrote: > This patch removes some GDBSERVER checks from nat/linux-ptrace.c. > Currently the code uses a compile-time check to decide whether some > flags should be used. This changes the code to instead let users of > the module specify an additional set of flags; and then changes gdb's > linux-nat.c to call this function. > At some later date, when the back > ends are fully merged, we will be able to remove this function again. > @@ -37,6 +37,10 @@ > there are no supported features. */ > static int current_ptrace_options = -1; > > +/* Additional flags to test. */ > + > +static int additional_flags; > + > /* Find all possible reasons we could fail to attach PID and append > these as strings to the already initialized BUFFER. '\0' > termination of BUFFER must be done by the caller. */ > @@ -359,16 +363,15 @@ linux_check_ptrace_features (void) > static void > linux_test_for_tracesysgood (int child_pid) > { > -#ifdef GDBSERVER > - /* gdbserver does not support PTRACE_O_TRACESYSGOOD. */ > -#else > - int ret; > + if ((additional_flags & PTRACE_O_TRACESYSGOOD) != 0) > + { Please avoid this indenting unless necessary, by reversing the logic: if ((additional_flags & PTRACE_O_TRACESYSGOOD) == 0) return; As this will end up being undone once additional_flags is removed again later on, this way avoid re-indenting back, and complicating history / git blame. > + int ret; > > - ret = ptrace (PTRACE_SETOPTIONS, child_pid, (PTRACE_TYPE_ARG3) 0, > - (PTRACE_TYPE_ARG4) PTRACE_O_TRACESYSGOOD); > - if (ret == 0) > - current_ptrace_options |= PTRACE_O_TRACESYSGOOD; > -#endif > + ret = ptrace (PTRACE_SETOPTIONS, child_pid, (PTRACE_TYPE_ARG3) 0, > + (PTRACE_TYPE_ARG4) PTRACE_O_TRACESYSGOOD); > + if (ret != 0) > + additional_flags &= ~PTRACE_O_TRACESYSGOOD; This isn't right. The function should still update current_ptrace_options (the effectively enabled options). Otherwise ... > + } > } > > /* Determine if PTRACE_O_TRACEFORK can be used to follow fork > @@ -388,16 +391,15 @@ linux_test_for_tracefork (int child_pid) > if (ret != 0) > return; > > -#ifdef GDBSERVER > - /* gdbserver does not support PTRACE_O_TRACEVFORKDONE yet. */ > -#else > - /* Check if the target supports PTRACE_O_TRACEVFORKDONE. */ > - ret = ptrace (PTRACE_SETOPTIONS, child_pid, (PTRACE_TYPE_ARG3) 0, > - (PTRACE_TYPE_ARG4) (PTRACE_O_TRACEFORK > - | PTRACE_O_TRACEVFORKDONE)); > - if (ret == 0) > - current_ptrace_options |= PTRACE_O_TRACEVFORKDONE; > -#endif > + if ((additional_flags & PTRACE_O_TRACEVFORKDONE) != 0) > + { > + /* Check if the target supports PTRACE_O_TRACEVFORKDONE. */ > + ret = ptrace (PTRACE_SETOPTIONS, child_pid, (PTRACE_TYPE_ARG3) 0, > + (PTRACE_TYPE_ARG4) (PTRACE_O_TRACEFORK > + | PTRACE_O_TRACEVFORKDONE)); > + if (ret != 0) > + additional_flags &= ~PTRACE_O_TRACEVFORKDONE; > + } > > /* Setting PTRACE_O_TRACEFORK did not cause an error, however we > don't know for sure that the feature is available; old > @@ -433,18 +435,7 @@ linux_test_for_tracefork (int child_pid) > > /* We got the PID from the grandchild, which means fork > tracing is supported. */ > -#ifdef GDBSERVER > - /* Do not enable all the options for now since gdbserver does not > - properly support them. This restriction will be lifted when > - gdbserver is augmented to support them. */ > - current_ptrace_options |= PTRACE_O_TRACECLONE; > -#else > - current_ptrace_options |= PTRACE_O_TRACEFORK | PTRACE_O_TRACEVFORK > - | PTRACE_O_TRACECLONE | PTRACE_O_TRACEEXEC; > - > - /* Do not enable PTRACE_O_TRACEEXIT until GDB is more prepared to > - support read-only process state. */ > -#endif > + current_ptrace_options |= PTRACE_O_TRACECLONE | additional_flags; ... note how PTRACE_O_TRACESYSGOOD is lost if PTRACE_O_TRACECLONE isn't supported. So don't clear additional_flags. Instead add to current_ptrace_options as options required in additional_flags are detected to be supported. -- Pedro Alves