From patchwork Thu Mar 31 10:05:19 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Florian Weimer X-Patchwork-Id: 11573 Received: (qmail 125874 invoked by alias); 31 Mar 2016 10:05:34 -0000 Mailing-List: contact libc-alpha-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Unsubscribe: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: libc-alpha-owner@sourceware.org Delivered-To: mailing list libc-alpha@sourceware.org Received: (qmail 125787 invoked by uid 89); 31 Mar 2016 10:05:33 -0000 Authentication-Results: sourceware.org; auth=none X-Virus-Found: No X-Spam-SWARE-Status: No, score=-2.9 required=5.0 tests=BAYES_00, RP_MATCHES_RCVD, SPF_HELO_PASS autolearn=ham version=3.3.2 spammy=snprintf, 12575, strchrnul X-HELO: mx1.redhat.com Subject: Re: [PATCH] Report dlsym, dlvsym lookup errors using dlerror [BZ #19509] To: "Carlos O'Donell" References: <56B9F83A.1000500@redhat.com> <56FBBE42.8010505@redhat.com> <56FC6634.8060405@redhat.com> Cc: libc-alpha@sourceware.org From: Florian Weimer Message-ID: <56FCF65F.5080101@redhat.com> Date: Thu, 31 Mar 2016 12:05:19 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.6.0 MIME-Version: 1.0 In-Reply-To: <56FC6634.8060405@redhat.com> On 03/31/2016 01:50 AM, Carlos O'Donell wrote: > On 03/30/2016 07:53 AM, Florian Weimer wrote: >> On 02/09/2016 03:31 PM, Florian Weimer wrote: >>> 2016-02-09 Florian Weimer >>> >>> [BZ #19509] >>> * elf/dl-lookup.c (_dl_lookup_symbol_x): Report error even if >>> skip_map != NULL. >>> * elf/bug19509.c: New file. >>> * elf/Makefile (tests): Add bug19509. >>> (bug19509): Link against libdl. >> >> Ping? >> >> https://sourceware.org/ml/libc-alpha/2016-02/msg00172.html > > I agree. The only caller with non-NULL skip_map is: > > 146 else if (handle == RTLD_NEXT) > 147 { > 148 if (__glibc_unlikely (match == GL(dl_ns)[LM_ID_BASE]._ns_loaded)) > 149 { > 150 if (match == NULL > 151 || caller < match->l_map_start > 152 || caller >= match->l_map_end) > 153 GLRO(dl_signal_error) (0, NULL, NULL, N_("\ > 154 RTLD_NEXT used in code not dynamically loaded")); > 155 } > 156 > 157 struct link_map *l = match; > 158 while (l->l_loader != NULL) > 159 l = l->l_loader; > 160 > 161 result = GLRO(dl_lookup_symbol_x) (name, match, &ref, l->l_local_scope, > 162 vers, 0, 0, match); > 163 } > > Whose purpose it is to skip the current map for lookup. > > Your patch and testcase look good to me. Thanks, here is what I committed. I renamed the test case based on previous comments on other threads. Thanks, Florian 2016-03-31 Florian Weimer [BZ #19509] * elf/dl-lookup.c (_dl_lookup_symbol_x): Report error even if skip_map != NULL. * elf/tst-dlsym-error.c: New file. * elf/Makefile (tests): Add tst-dlsym-error. (tst-dlsym-error): Link against libdl. diff --git a/elf/Makefile b/elf/Makefile index 7b6d6d7..bb23d93 100644 --- a/elf/Makefile +++ b/elf/Makefile @@ -149,7 +149,7 @@ tests += loadtest restest1 preloadtest loadfail multiload origtest resolvfail \ tst-nodelete) \ tst-initorder tst-initorder2 tst-relsort1 tst-null-argv \ tst-ptrguard1 tst-tlsalign tst-tlsalign-extern tst-nodelete-opened \ - tst-nodelete2 tst-audit11 tst-audit12 + tst-nodelete2 tst-audit11 tst-audit12 tst-dlsym-error # reldep9 ifeq ($(build-hardcoded-path-in-tests),yes) tests += tst-dlopen-aout @@ -1257,3 +1257,5 @@ $(objpfx)tst-prelink-cmp.out: tst-prelink.exp \ $(objpfx)tst-ldconfig-X.out : tst-ldconfig-X.sh $(objpfx)ldconfig $(SHELL) $< '$(common-objpfx)' '$(test-wrapper)' '$(test-wrapper-env)' > $@; \ $(evaluate-test) + +$(objpfx)tst-dlsym-error: $(libdl) diff --git a/elf/dl-lookup.c b/elf/dl-lookup.c index f577759..6d299c1 100644 --- a/elf/dl-lookup.c +++ b/elf/dl-lookup.c @@ -858,7 +858,6 @@ _dl_lookup_symbol_x (const char *undef_name, struct link_map *undef_map, if (__glibc_unlikely (current_value.s == NULL)) { if ((*ref == NULL || ELFW(ST_BIND) ((*ref)->st_info) != STB_WEAK) - && skip_map == NULL && !(GLRO(dl_debug_mask) & DL_DEBUG_UNUSED)) { /* We could find no value for a strong reference. */ diff --git a/elf/tst-dlsym-error.c b/elf/tst-dlsym-error.c new file mode 100644 index 0000000..11b0358 --- /dev/null +++ b/elf/tst-dlsym-error.c @@ -0,0 +1,113 @@ +/* Test error reporting for dlsym, dlvsym failures. + Copyright (C) 2016 Free Software Foundation, Inc. + This file is part of the GNU C Library. + + The GNU C Library is free software; you can redistribute it and/or + modify it under the terms of the GNU Lesser General Public + License as published by the Free Software Foundation; either + version 2.1 of the License, or (at your option) any later version. + + The GNU C Library is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public + License along with the GNU C Library; if not, see + . */ + +#include +#include +#include +#include + +/* Used to disambiguate symbol names. */ +static int counter; + +static void +test_one (void *handle, const char *name, void *(func) (void *, const char *), + const char *suffix) +{ + ++counter; + char symbol[32]; + snprintf (symbol, sizeof (symbol), "no_such_symbol_%d", counter); + char *expected_message; + if (asprintf (&expected_message, ": undefined symbol: %s%s", + symbol, suffix) < 0) + { + printf ("error: asprintf: %m\n"); + abort (); + } + + void *addr = func (handle, symbol); + if (addr != NULL) + { + printf ("error: %s: found symbol \"no_such_symbol\"\n", name); + abort (); + } + const char *message = dlerror (); + if (message == NULL) + { + printf ("error: %s: missing error message\n", name); + abort (); + } + const char *message_without_path = strchrnul (message, ':'); + if (strcmp (message_without_path, expected_message) != 0) + { + printf ("error: %s: unexpected error message: %s\n", name, message); + abort (); + } + free (expected_message); + + message = dlerror (); + if (message != NULL) + { + printf ("error: %s: unexpected error message: %s\n", name, message); + abort (); + } +} + +static void +test_handles (const char *name, void *(func) (void *, const char *), + const char *suffix) +{ + test_one (RTLD_DEFAULT, name, func, suffix); + test_one (RTLD_NEXT, name, func, suffix); + + void *handle = dlopen (LIBC_SO, RTLD_LAZY); + if (handle == NULL) + { + printf ("error: cannot dlopen %s: %s\n", LIBC_SO, dlerror ()); + abort (); + } + test_one (handle, name, func, suffix); + dlclose (handle); +} + +static void * +dlvsym_no_such_version (void *handle, const char *name) +{ + return dlvsym (handle, name, "NO_SUCH_VERSION"); +} + +static void * +dlvsym_glibc_private (void *handle, const char *name) +{ + return dlvsym (handle, name, "GLIBC_PRIVATE"); +} + +static int +do_test (void) +{ + test_handles ("dlsym", dlsym, ""); + test_handles ("dlvsym", dlvsym_no_such_version, + ", version NO_SUCH_VERSION"); + test_handles ("dlvsym", dlvsym_glibc_private, + ", version GLIBC_PRIVATE"); + + return 0; +} + + +#define TEST_FUNCTION do_test () +#include "../test-skeleton.c"