From patchwork Wed Mar 19 03:57:51 2014 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Hui Zhu X-Patchwork-Id: 152 Return-Path: X-Original-To: siddhesh@wilcox.dreamhost.com Delivered-To: siddhesh@wilcox.dreamhost.com Received: from homiemail-mx20.g.dreamhost.com (caibbdcaaahc.dreamhost.com [208.113.200.72]) by wilcox.dreamhost.com (Postfix) with ESMTP id D003936007A for ; Tue, 18 Mar 2014 20:58:08 -0700 (PDT) Received: by homiemail-mx20.g.dreamhost.com (Postfix, from userid 14314964) id 8322440CFC115; Tue, 18 Mar 2014 20:58:08 -0700 (PDT) X-Original-To: gdb@patchwork.siddhesh.in Delivered-To: x14314964@homiemail-mx20.g.dreamhost.com Received: from sourceware.org (server1.sourceware.org [209.132.180.131]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by homiemail-mx20.g.dreamhost.com (Postfix) with ESMTPS id 639D140C6F9E7 for ; Tue, 18 Mar 2014 20:58:08 -0700 (PDT) DomainKey-Signature: a=rsa-sha1; c=nofws; d=sourceware.org; h=list-id :list-unsubscribe:list-subscribe:list-archive:list-post :list-help:sender:message-id:date:from:mime-version:to:cc :subject:references:in-reply-to:content-type :content-transfer-encoding; q=dns; s=default; b=hOYtjZSwKaKqW+9K 2HRYHTBqxSf6xnAUFXLI4S4EdFo7AUEpkBfEFmYR5trmgrPVDz3l5w18NDjJojsn 8oEtgJZ8d0VUs1+A0Vs/yiKXNotvPzTNMh4SLuKBGNGiPJYyV6vUqVmqxIgoA4uW 8FLSx5HnLEJd3fx2RUVnmwrE0ww= DKIM-Signature: v=1; a=rsa-sha1; c=relaxed; d=sourceware.org; h=list-id :list-unsubscribe:list-subscribe:list-archive:list-post :list-help:sender:message-id:date:from:mime-version:to:cc :subject:references:in-reply-to:content-type :content-transfer-encoding; s=default; bh=647QRNDN4ezpfGlaA3R0pW 8Ig68=; b=qRtMJhQo8Q0A+P9poWoZchlMD/mFdoLkvZlheuW/aAUGjQie60RiX9 oGR3QbqlfALn66k4CxKx35e4kVIv1EejqksFjleasieg4HMlZI5X/XsHor1HZPXM i70rcKD2+queFBjIK7TbxPw+WlMRUJgSMuGxBVcQEjzwdbtXYMItw= Received: (qmail 26364 invoked by alias); 19 Mar 2014 03:58:06 -0000 Mailing-List: contact gdb-patches-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Unsubscribe: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: gdb-patches-owner@sourceware.org Delivered-To: mailing list gdb-patches@sourceware.org Received: (qmail 26351 invoked by uid 89); 19 Mar 2014 03:58:05 -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 autolearn=ham version=3.3.2 X-HELO: relay1.mentorg.com Received: from relay1.mentorg.com (HELO relay1.mentorg.com) (192.94.38.131) by sourceware.org (qpsmtpd/0.93/v0.84-503-g423c35a) with ESMTP; Wed, 19 Mar 2014 03:58:04 +0000 Received: from svr-orw-fem-01.mgc.mentorg.com ([147.34.98.93]) by relay1.mentorg.com with esmtp id 1WQ7df-0002rY-Vb from Hui_Zhu@mentor.com ; Tue, 18 Mar 2014 20:58:00 -0700 Received: from SVR-ORW-FEM-02.mgc.mentorg.com ([147.34.96.206]) by svr-orw-fem-01.mgc.mentorg.com over TLS secured channel with Microsoft SMTPSVC(6.0.3790.4675); Tue, 18 Mar 2014 20:57:59 -0700 Received: from localhost.localdomain (147.34.91.1) by svr-orw-fem-02.mgc.mentorg.com (147.34.96.168) with Microsoft SMTP Server id 14.2.247.3; Tue, 18 Mar 2014 20:57:59 -0700 Message-ID: <532915BF.2090608@mentor.com> Date: Wed, 19 Mar 2014 11:57:51 +0800 From: Hui Zhu User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:24.0) Gecko/20100101 Thunderbird/24.3.0 MIME-Version: 1.0 To: Pedro Alves CC: gdb-patches ml Subject: Re: [PATCH 0/1] Fix internal warning when "gdb -p xxx" References: <53271C09.5000709@mentor.com> <53271ED2.6010707@redhat.com> <53272958.1080605@redhat.com> <5327F7D0.1050304@mentor.com> <53281C69.7090703@redhat.com> In-Reply-To: <53281C69.7090703@redhat.com> X-IsSubscribed: yes X-DH-Original-To: gdb@patchwork.siddhesh.in On 03/18/14 18:14, Pedro Alves wrote: > On 03/18/2014 07:37 AM, Hui Zhu wrote: >> On 03/18/14 00:56, Pedro Alves wrote: > >> According to your comments, I make a new patch that change all >> methods return a static buffer. > > Thank you. > >>> Bummer that we don't have a test that caught this. :-( >>> >> >> Yes, I found it when I did regression test. > > WDYM? What test failed then? Sorry, my mean is I found the issue cannot be found by regression test. > >> Does testsuite have some example to test a GDB feature like "gdb -p"? > > I guess we'd refactor attach.exp a little to test that in addition > to "attach", on native targets. And I supposed we could pass down the > -p to gdb by tweaking GDBFLAGS, like several tests do. gdb.base/corefile.exp > sounds like the model to follow, as that spawns "gdb -core", which is very > similar to "gdb -p". I make a patch for that. I will post it in a separate mail. > >> 2014-03-18 Hui Zhu >> >> * darwin-nat.c (darwin_pid_to_exec_file): Change xmalloc to >> static buffer. >> * fbsd-nat.c (fbsd_pid_to_exec_file): Ditto. >> * linux-nat.c (linux_child_pid_to_exec_file): Ditto. >> * nbsd-nat.c (nbsd_pid_to_exec_file): Ditto. >> >> --- a/gdb/darwin-nat.c >> +++ b/gdb/darwin-nat.c >> @@ -1991,12 +1991,9 @@ set_enable_mach_exceptions (char *args, >> static char * >> darwin_pid_to_exec_file (struct target_ops *self, int pid) >> { >> - char *path; >> + static char path[PATH_MAX]; >> int res; >> >> - path = xmalloc (PATH_MAX); >> - make_cleanup (xfree, path); >> - >> res = proc_pidinfo (pid, PROC_PIDPATHINFO, 0, path, PATH_MAX); >> if (res >= 0) >> return path; >> --- a/gdb/fbsd-nat.c >> +++ b/gdb/fbsd-nat.c >> @@ -40,8 +40,8 @@ char * >> fbsd_pid_to_exec_file (struct target_ops *self, int pid) >> { >> size_t len = PATH_MAX; >> - char *buf = xcalloc (len, sizeof (char)); >> - char *path; >> + static char buf[PATH_MAX]; >> + char *path, *ret; >> >> #ifdef KERN_PROC_PATHNAME >> int mib[4]; >> @@ -56,13 +56,12 @@ fbsd_pid_to_exec_file (struct target_ops >> >> path = xstrprintf ("/proc/%d/file", pid); >> if (readlink (path, buf, PATH_MAX - 1) == -1) > > readlink does not '\0' terminate, we need to do that ourselves. > See below. > >> - { >> - xfree (buf); >> - buf = NULL; >> - } >> + ret = NULL; >> + else >> + ret = buf; >> >> xfree (path); >> - return buf; >> + return ret; >> } >> >> static int >> --- a/gdb/linux-nat.c >> +++ b/gdb/linux-nat.c >> @@ -4011,19 +4011,18 @@ linux_nat_thread_name (struct target_ops >> static char * >> linux_child_pid_to_exec_file (struct target_ops *self, int pid) >> { >> - char *name1, *name2; >> + static char buf[PATH_MAX]; >> + char name1[PATH_MAX], name2[PATH_MAX]; >> >> - name1 = xmalloc (PATH_MAX); >> - name2 = xmalloc (PATH_MAX); >> - make_cleanup (xfree, name1); >> - make_cleanup (xfree, name2); >> memset (name2, 0, PATH_MAX); >> >> xsnprintf (name1, PATH_MAX, "/proc/%d/exe", pid); >> if (readlink (name1, name2, PATH_MAX - 1) > 0) >> - return name2; >> + strcpy (buf, name2); >> else >> - return name1; >> + strcpy (buf, name1); >> + >> + return buf; > > No need for three buffers. AFAICS, this should suffice: > > static char buf[PATH_MAX]; > char name[PATH_MAX]; > > xsnprintf (name, PATH_MAX, "/proc/%d/exe", pid); > memset (buf, 0, PATH_MAX); > if (readlink (name, buf, PATH_MAX - 1) <= 0) > strcpy (buf, name); > return buf; > >> } >> >> /* Records the thread's register state for the corefile note >> --- a/gdb/nbsd-nat.c >> +++ b/gdb/nbsd-nat.c >> @@ -28,16 +28,15 @@ char * >> nbsd_pid_to_exec_file (struct target_ops *self, int pid) >> { >> size_t len = PATH_MAX; >> - char *buf = xcalloc (len, sizeof (char)); >> - char *path; >> + static char buf[PATH_MAX]; >> + char *path, *ret; >> >> path = xstrprintf ("/proc/%d/exe", pid); >> if (readlink (path, buf, PATH_MAX - 1) == -1) >> - { >> - xfree (buf); >> - buf = NULL; >> - } >> + ret = NULL; >> + else >> + ret = buf; >> >> xfree (path); >> - return buf; >> + return ret; >> } > > Same with the nul termination. The most standard solution is: > > static char buf[PATH_MAX]; > char name[PATH_MAX]; > ssize_t len; > > xsnprintf (name, PATH_MAX, "/proc/%d/exe", pid); > len = readlink (name, buf, PATH_MAX - 1); > if (len != -1) > { > buf[len] = '\0'; > return buf; > } > return NULL; > I make a new patch according to your comments. Please help me review it. Thanks, Hui 2014-03-19 Hui Zhu Pedro Alves * darwin-nat.c (darwin_pid_to_exec_file): Change xmalloc to static buffer. * fbsd-nat.c (fbsd_pid_to_exec_file): Ditto. * linux-nat.c (linux_child_pid_to_exec_file): Ditto. * nbsd-nat.c (nbsd_pid_to_exec_file): Ditto. --- a/gdb/darwin-nat.c +++ b/gdb/darwin-nat.c @@ -1991,12 +1991,9 @@ set_enable_mach_exceptions (char *args, static char * darwin_pid_to_exec_file (struct target_ops *self, int pid) { - char *path; + static char path[PATH_MAX]; int res; - path = xmalloc (PATH_MAX); - make_cleanup (xfree, path); - res = proc_pidinfo (pid, PROC_PIDPATHINFO, 0, path, PATH_MAX); if (res >= 0) return path; --- a/gdb/fbsd-nat.c +++ b/gdb/fbsd-nat.c @@ -40,8 +40,8 @@ char * fbsd_pid_to_exec_file (struct target_ops *self, int pid) { size_t len = PATH_MAX; - char *buf = xcalloc (len, sizeof (char)); - char *path; + static char buf[PATH_MAX]; + char name[PATH_MAX]; #ifdef KERN_PROC_PATHNAME int mib[4]; @@ -54,14 +54,11 @@ fbsd_pid_to_exec_file (struct target_ops return buf; #endif - path = xstrprintf ("/proc/%d/file", pid); - if (readlink (path, buf, PATH_MAX - 1) == -1) - { - xfree (buf); - buf = NULL; - } + xsnprintf (name, PATH_MAX, "/proc/%d/exe", pid); + memset (buf, 0, PATH_MAX); + if (readlink (name, buf, PATH_MAX - 1) <= 0) + strcpy (buf, name); - xfree (path); return buf; } --- a/gdb/linux-nat.c +++ b/gdb/linux-nat.c @@ -4011,19 +4011,15 @@ linux_nat_thread_name (struct target_ops static char * linux_child_pid_to_exec_file (struct target_ops *self, int pid) { - char *name1, *name2; + static char buf[PATH_MAX]; + char name[PATH_MAX]; - name1 = xmalloc (PATH_MAX); - name2 = xmalloc (PATH_MAX); - make_cleanup (xfree, name1); - make_cleanup (xfree, name2); - memset (name2, 0, PATH_MAX); + xsnprintf (name, PATH_MAX, "/proc/%d/exe", pid); + memset (buf, 0, PATH_MAX); + if (readlink (name, buf, PATH_MAX - 1) <= 0) + strcpy (buf, name); - xsnprintf (name1, PATH_MAX, "/proc/%d/exe", pid); - if (readlink (name1, name2, PATH_MAX - 1) > 0) - return name2; - else - return name1; + return buf; } /* Records the thread's register state for the corefile note --- a/gdb/nbsd-nat.c +++ b/gdb/nbsd-nat.c @@ -27,17 +27,13 @@ char * nbsd_pid_to_exec_file (struct target_ops *self, int pid) { - size_t len = PATH_MAX; - char *buf = xcalloc (len, sizeof (char)); - char *path; + static char buf[PATH_MAX]; + char name[PATH_MAX]; - path = xstrprintf ("/proc/%d/exe", pid); - if (readlink (path, buf, PATH_MAX - 1) == -1) - { - xfree (buf); - buf = NULL; - } + xsnprintf (name, PATH_MAX, "/proc/%d/exe", pid); + memset (buf, 0, PATH_MAX); + if (readlink (name, buf, PATH_MAX - 1) <= 0) + strcpy (buf, name); - xfree (path); return buf; }