From owner-svn-src-head@freebsd.org Mon Oct 22 21:25:29 2018 Return-Path: Delivered-To: svn-src-head@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id B403BFD74E7; Mon, 22 Oct 2018 21:25:29 +0000 (UTC) (envelope-from jhb@FreeBSD.org) Received: from mxrelay.nyi.freebsd.org (mxrelay.nyi.freebsd.org [IPv6:2610:1c1:1:606c::19:3]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client CN "mxrelay.nyi.freebsd.org", Issuer "Let's Encrypt Authority X3" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 6A07474CB5; Mon, 22 Oct 2018 21:25:29 +0000 (UTC) (envelope-from jhb@FreeBSD.org) Received: from repo.freebsd.org (repo.freebsd.org [IPv6:2610:1c1:1:6068::e6a:0]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client did not present a certificate) by mxrelay.nyi.freebsd.org (Postfix) with ESMTPS id 4C56A25E7E; Mon, 22 Oct 2018 21:25:29 +0000 (UTC) (envelope-from jhb@FreeBSD.org) Received: from repo.freebsd.org ([127.0.1.37]) by repo.freebsd.org (8.15.2/8.15.2) with ESMTP id w9MLPT1p029048; Mon, 22 Oct 2018 21:25:29 GMT (envelope-from jhb@FreeBSD.org) Received: (from jhb@localhost) by repo.freebsd.org (8.15.2/8.15.2/Submit) id w9MLPSUc029046; Mon, 22 Oct 2018 21:25:28 GMT (envelope-from jhb@FreeBSD.org) Message-Id: <201810222125.w9MLPSUc029046@repo.freebsd.org> X-Authentication-Warning: repo.freebsd.org: jhb set sender to jhb@FreeBSD.org using -f From: John Baldwin Date: Mon, 22 Oct 2018 21:25:28 +0000 (UTC) To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r339620 - head/usr.bin/ktrdump X-SVN-Group: head X-SVN-Commit-Author: jhb X-SVN-Commit-Paths: head/usr.bin/ktrdump X-SVN-Commit-Revision: 339620 X-SVN-Commit-Repository: base MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-BeenThere: svn-src-head@freebsd.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: SVN commit messages for the src tree for head/-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 22 Oct 2018 21:25:29 -0000 Author: jhb Date: Mon Oct 22 21:25:28 2018 New Revision: 339620 URL: https://svnweb.freebsd.org/changeset/base/339620 Log: Add a "live" mode to ktrdump. Support a "live" mode in ktrdump enabled via the -l flag. In this mode, ktrdump polls the kernel's trace buffer periodically (currently hardcoded as a 50 millisecond interval) and dumps any newly added entries. Fancier logic for the timeout (e.g. a command line option or some kind of backoff based on the time since the last entry) can be added later as the need arises. While here, fix some bugs from when this was Capsicum-ized: - Use caph_limit_stream() for the output stream so that isatty() works and the output can be line-buffered (especially useful for live mode). - Use caph_limit_stderr() to permit error messages to be displayed if an error occurs after cap_enter(). Reviewed by: kib, 0mp (manpage) MFC after: 2 months Differential Revision: https://reviews.freebsd.org/D17315 Modified: head/usr.bin/ktrdump/ktrdump.8 head/usr.bin/ktrdump/ktrdump.c Modified: head/usr.bin/ktrdump/ktrdump.8 ============================================================================== --- head/usr.bin/ktrdump/ktrdump.8 Mon Oct 22 21:17:36 2018 (r339619) +++ head/usr.bin/ktrdump/ktrdump.8 Mon Oct 22 21:25:28 2018 (r339620) @@ -25,7 +25,7 @@ .\" .\" $FreeBSD$ .\" -.Dd February 6, 2015 +.Dd October 22, 2018 .Dt KTRDUMP 8 .Os .Sh NAME @@ -33,7 +33,7 @@ .Nd print kernel ktr trace buffer .Sh SYNOPSIS .Nm -.Op Fl cfqrtH +.Op Fl cflqrtH .Op Fl i Ar ktrfile .Op Fl M Ar core .Op Fl N Ar system @@ -47,6 +47,9 @@ The following options are available: .Bl -tag -width ".Fl i Ar ktrfile" .It Fl c Print the CPU number that each entry was logged from. +.It Fl l +Poll the kernel ktr trace buffer periodically dumping any new events after +each poll. .It Fl f Print the file and line number that each entry was logged from. .It Fl q Modified: head/usr.bin/ktrdump/ktrdump.c ============================================================================== --- head/usr.bin/ktrdump/ktrdump.c Mon Oct 22 21:17:36 2018 (r339619) +++ head/usr.bin/ktrdump/ktrdump.c Mon Oct 22 21:25:28 2018 (r339620) @@ -51,7 +51,7 @@ __FBSDID("$FreeBSD$"); #define SBUFLEN 128 #define USAGE \ - "usage: ktrdump [-cfqrtH] [-i ktrfile] [-M core] [-N system] [-o outfile]\n" + "usage: ktrdump [-cflqrtH] [-i ktrfile] [-M core] [-N system] [-o outfile]\n" static void usage(void); @@ -65,6 +65,7 @@ static struct nlist nl[] = { static int cflag; static int fflag; +static int lflag; static int Mflag; static int Nflag; static int qflag; @@ -111,7 +112,7 @@ main(int ac, char **av) * Parse commandline arguments. */ out = stdout; - while ((c = getopt(ac, av, "cfqrtHe:i:m:M:N:o:")) != -1) + while ((c = getopt(ac, av, "cflqrtHe:i:m:M:N:o:")) != -1) switch (c) { case 'c': cflag = 1; @@ -136,6 +137,9 @@ main(int ac, char **av) err(1, "unable to limit rights for %s", optarg); break; + case 'l': + lflag = 1; + break; case 'M': case 'm': if (strlcpy(corefile, optarg, sizeof(corefile)) @@ -169,9 +173,10 @@ main(int ac, char **av) if (ac != 0) usage(); - cap_rights_init(&rights, CAP_FSTAT, CAP_WRITE); - if (cap_rights_limit(fileno(out), &rights) < 0 && errno != ENOSYS) + if (caph_limit_stream(fileno(out), CAPH_WRITE) < 0) err(1, "unable to limit rights for %s", outfile); + if (caph_limit_stderr() < 0) + err(1, "unable to limit rights for stderr"); /* * Open our execfile and corefile, resolve needed symbols and read in @@ -258,15 +263,29 @@ main(int ac, char **av) fprintf(out, "\n"); } + tlast = -1; /* * Now tear through the trace buffer. + * + * In "live" mode, find the oldest entry (first non-NULL entry + * after index2) and walk forward. Otherwise, start with the + * most recent entry and walk backwards. */ if (!iflag) { - i = index - 1; - if (i < 0) - i = entries - 1; + if (lflag) { + i = index2 + 1 % entries; + while (buf[i].ktr_desc == NULL && i != index) { + i++; + if (i == entries) + i = 0; + } + } else { + i = index - 1; + if (i < 0) + i = entries - 1; + } } - tlast = -1; +dump_entries: for (;;) { if (buf[i].ktr_desc == NULL) break; @@ -338,14 +357,40 @@ next: if ((c = *p++) == '\0') * 'index2' were in flux while the KTR buffer was * being copied to userspace we don't dump them. */ - if (i == index2) - break; - if (--i < 0) - i = entries - 1; + if (lflag) { + if (++i == entries) + i = 0; + if (i == index) + break; + } else { + if (i == index2) + break; + if (--i < 0) + i = entries - 1; + } } else { if (++i == entries) break; } + } + + /* + * In "live" mode, poll 'ktr_idx' periodically and dump any + * new entries since our last pass through the ring. + */ + if (lflag && !iflag) { + while (index == index2) { + usleep(50 * 1000); + if (kvm_read(kd, nl[2].n_value, &index2, + sizeof(index2)) == -1) + errx(1, "%s", kvm_geterr(kd)); + } + i = index; + index = index2; + if (kvm_read(kd, bufptr, buf, sizeof(*buf) * entries) == -1 || + kvm_read(kd, nl[2].n_value, &index2, sizeof(index2)) == -1) + errx(1, "%s", kvm_geterr(kd)); + goto dump_entries; } return (0);