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Tue, 06 Oct 2020 14:06:11 -0700 (PDT) Received: from [192.168.1.4] ([177.194.48.209]) by smtp.googlemail.com with ESMTPSA id x25sm15593qtp.64.2020.10.06.14.06.10 for (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Tue, 06 Oct 2020 14:06:10 -0700 (PDT) Subject: Re: [PATCH 05/28] elf: Move ld.so error/help output to _dl_usage To: libc-alpha@sourceware.org References: <82d06d8f60646b8f6e7f13ba42668e3ea10e0268.1601569371.git.fweimer@redhat.com> From: Adhemerval Zanella Autocrypt: addr=adhemerval.zanella@linaro.org; prefer-encrypt=mutual; keydata= mQINBFcVGkoBEADiQU2x/cBBmAVf5C2d1xgz6zCnlCefbqaflUBw4hB/bEME40QsrVzWZ5Nq 8kxkEczZzAOKkkvv4pRVLlLn/zDtFXhlcvQRJ3yFMGqzBjofucOrmdYkOGo0uCaoJKPT186L NWp53SACXguFJpnw4ODI64ziInzXQs/rUJqrFoVIlrPDmNv/LUv1OVPKz20ETjgfpg8MNwG6 iMizMefCl+RbtXbIEZ3TE/IaDT/jcOirjv96lBKrc/pAL0h/O71Kwbbp43fimW80GhjiaN2y WGByepnkAVP7FyNarhdDpJhoDmUk9yfwNuIuESaCQtfd3vgKKuo6grcKZ8bHy7IXX1XJj2X/ BgRVhVgMHAnDPFIkXtP+SiarkUaLjGzCz7XkUn4XAGDskBNfbizFqYUQCaL2FdbW3DeZqNIa nSzKAZK7Dm9+0VVSRZXP89w71Y7JUV56xL/PlOE+YKKFdEw+gQjQi0e+DZILAtFjJLoCrkEX w4LluMhYX/X8XP6/C3xW0yOZhvHYyn72sV4yJ1uyc/qz3OY32CRy+bwPzAMAkhdwcORA3JPb kPTlimhQqVgvca8m+MQ/JFZ6D+K7QPyvEv7bQ7M+IzFmTkOCwCJ3xqOD6GjX3aphk8Sr0dq3 4Awlf5xFDAG8dn8Uuutb7naGBd/fEv6t8dfkNyzj6yvc4jpVxwARAQABtElBZGhlbWVydmFs IFphbmVsbGEgTmV0dG8gKExpbmFybyBWUE4gS2V5KSA8YWRoZW1lcnZhbC56YW5lbGxhQGxp bmFyby5vcmc+iQI3BBMBCAAhBQJXFRpKAhsDBQsJCAcDBRUKCQgLBRYCAwEAAh4BAheAAAoJ EKqx7BSnlIjv0e8P/1YOYoNkvJ+AJcNUaM5a2SA9oAKjSJ/M/EN4Id5Ow41ZJS4lUA0apSXW NjQg3VeVc2RiHab2LIB4MxdJhaWTuzfLkYnBeoy4u6njYcaoSwf3g9dSsvsl3mhtuzm6aXFH /Qsauav77enJh99tI4T+58rp0EuLhDsQbnBic/ukYNv7sQV8dy9KxA54yLnYUFqH6pfH8Lly sTVAMyi5Fg5O5/hVV+Z0Kpr+ZocC1YFJkTsNLAW5EIYSP9ftniqaVsim7MNmodv/zqK0IyDB GLLH1kjhvb5+6ySGlWbMTomt/or/uvMgulz0bRS+LUyOmlfXDdT+t38VPKBBVwFMarNuREU2 69M3a3jdTfScboDd2ck1u7l+QbaGoHZQ8ZNUrzgObltjohiIsazqkgYDQzXIMrD9H19E+8fw kCNUlXxjEgH/Kg8DlpoYJXSJCX0fjMWfXywL6ZXc2xyG/hbl5hvsLNmqDpLpc1CfKcA0BkK+ k8R57fr91mTCppSwwKJYO9T+8J+o4ho/CJnK/jBy1pWKMYJPvvrpdBCWq3MfzVpXYdahRKHI ypk8m4QlRlbOXWJ3TDd/SKNfSSrWgwRSg7XCjSlR7PNzNFXTULLB34sZhjrN6Q8NQZsZnMNs TX8nlGOVrKolnQPjKCLwCyu8PhllU8OwbSMKskcD1PSkG6h3r0AquQINBFcVGkoBEACgAdbR Ck+fsfOVwT8zowMiL3l9a2DP3Eeak23ifdZG+8Avb/SImpv0UMSbRfnw/N81IWwlbjkjbGTu oT37iZHLRwYUFmA8fZX0wNDNKQUUTjN6XalJmvhdz9l71H3WnE0wneEM5ahu5V1L1utUWTyh VUwzX1lwJeV3vyrNgI1kYOaeuNVvq7npNR6t6XxEpqPsNc6O77I12XELic2+36YibyqlTJIQ V1SZEbIy26AbC2zH9WqaKyGyQnr/IPbTJ2Lv0dM3RaXoVf+CeK7gB2B+w1hZummD21c1Laua +VIMPCUQ+EM8W9EtX+0iJXxI+wsztLT6vltQcm+5Q7tY+HFUucizJkAOAz98YFucwKefbkTp eKvCfCwiM1bGatZEFFKIlvJ2QNMQNiUrqJBlW9nZp/k7pbG3oStOjvawD9ZbP9e0fnlWJIsj 6c7pX354Yi7kxIk/6gREidHLLqEb/otuwt1aoMPg97iUgDV5mlNef77lWE8vxmlY0FBWIXuZ yv0XYxf1WF6dRizwFFbxvUZzIJp3spAao7jLsQj1DbD2s5+S1BW09A0mI/1DjB6EhNN+4bDB SJCOv/ReK3tFJXuj/HbyDrOdoMt8aIFbe7YFLEExHpSk+HgN05Lg5TyTro8oW7TSMTk+8a5M kzaH4UGXTTBDP/g5cfL3RFPl79ubXwARAQABiQIfBBgBCAAJBQJXFRpKAhsMAAoJEKqx7BSn lIjvI/8P/jg0jl4Tbvg3B5kT6PxJOXHYu9OoyaHLcay6Cd+ZrOd1VQQCbOcgLFbf4Yr+rE9l mYsY67AUgq2QKmVVbn9pjvGsEaz8UmfDnz5epUhDxC6yRRvY4hreMXZhPZ1pbMa6A0a/WOSt AgFj5V6Z4dXGTM/lNManr0HjXxbUYv2WfbNt3/07Db9T+GZkpUotC6iknsTA4rJi6u2ls0W9 1UIvW4o01vb4nZRCj4rni0g6eWoQCGoVDk/xFfy7ZliR5B+3Z3EWRJcQskip/QAHjbLa3pml xAZ484fVxgeESOoaeC9TiBIp0NfH8akWOI0HpBCiBD5xaCTvR7ujUWMvhsX2n881r/hNlR9g fcE6q00qHSPAEgGr1bnFv74/1vbKtjeXLCcRKk3Ulw0bY1OoDxWQr86T2fZGJ/HIZuVVBf3+ gaYJF92GXFynHnea14nFFuFgOni0Mi1zDxYH/8yGGBXvo14KWd8JOW0NJPaCDFJkdS5hu0VY 7vJwKcyHJGxsCLU+Et0mryX8qZwqibJIzu7kUJQdQDljbRPDFd/xmGUFCQiQAncSilYOcxNU EMVCXPAQTteqkvA+gNqSaK1NM9tY0eQ4iJpo+aoX8HAcn4sZzt2pfUB9vQMTBJ2d4+m/qO6+ cFTAceXmIoFsN8+gFN3i8Is3u12u8xGudcBPvpoy4OoG Message-ID: <615ab9ee-2313-587d-6f6f-8450752b889e@linaro.org> Date: Tue, 6 Oct 2020 18:06:08 -0300 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.10.0 MIME-Version: 1.0 In-Reply-To: <82d06d8f60646b8f6e7f13ba42668e3ea10e0268.1601569371.git.fweimer@redhat.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit X-Spam-Status: No, score=-13.5 required=5.0 tests=BAYES_00, DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, DKIM_VALID_EF, GIT_PATCH_0, KAM_SHORT, NICE_REPLY_A, RCVD_IN_DNSWL_NONE, SPF_HELO_NONE, SPF_PASS, TXREP autolearn=ham autolearn_force=no version=3.4.2 X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on server2.sourceware.org X-BeenThere: libc-alpha@sourceware.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Libc-alpha mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 06 Oct 2020 21:06:14 -0000 On 01/10/2020 13:32, Florian Weimer via Libc-alpha wrote: > Also add a comment to elf/Makefile, explaining why we cannot use > config.status for autoconf template processing. LGTM, with just a nit below. Reviewed-by: Adhemerval Zanella > --- > elf/Makefile | 9 ++++++++- > elf/dl-main.h | 5 +++++ > elf/dl-usage.c | 51 ++++++++++++++++++++++++++++++++++++++++++++++++++ > elf/rtld.c | 26 +------------------------ > 4 files changed, 65 insertions(+), 26 deletions(-) > create mode 100644 elf/dl-usage.c > > diff --git a/elf/Makefile b/elf/Makefile > index ab792d45c2..71602d04c1 100644 > --- a/elf/Makefile > +++ b/elf/Makefile > @@ -59,7 +59,7 @@ elide-routines.os = $(all-dl-routines) dl-support enbl-secure dl-origin \ > # ld.so uses those routines, plus some special stuff for being the program > # interpreter and operating independent of libc. > rtld-routines = rtld $(all-dl-routines) dl-sysdep dl-environ dl-minimal \ > - dl-error-minimal dl-conflict dl-hwcaps > + dl-error-minimal dl-conflict dl-hwcaps dl-usage > all-rtld-routines = $(rtld-routines) $(sysdep-rtld-routines) > > CFLAGS-dl-runtime.c += -fexceptions -fasynchronous-unwind-tables Ok. > @@ -618,6 +618,12 @@ ldso_install: $(inst_rtlddir)/$(rtld-installed-name) > endif > > > +# Workarounds for ${exec_prefix} expansion in configure variables. > +# config.status cannot be used directly for processing ldd.bash.in or > +# expanding variables such as sysconfdir because the expansion > +# contains the literal string ${exec_prefix}, which is not valid in C > +# headers or installed shell scripts. > + > ldd-rewrite = -e 's%@RTLD@%$(rtlddir)/$(rtld-installed-name)%g' \ > -e 's%@VERSION@%$(version)%g' \ > -e 's|@PKGVERSION@|$(PKGVERSION)|g' \ > @@ -655,6 +661,7 @@ libof-ldconfig = ldconfig > CFLAGS-dl-cache.c += $(SYSCONF-FLAGS) > CFLAGS-cache.c += $(SYSCONF-FLAGS) > CFLAGS-rtld.c += $(SYSCONF-FLAGS) > +CFLAGS-dl-usage.c += $(SYSCONF-FLAGS) > > cpp-srcs-left := $(all-rtld-routines:=.os) > lib := rtld Ok. > diff --git a/elf/dl-main.h b/elf/dl-main.h > index ad9250171f..681f366871 100644 > --- a/elf/dl-main.h > +++ b/elf/dl-main.h > @@ -19,7 +19,9 @@ > #ifndef _DL_MAIN > #define _DL_MAIN > > +#include > #include > +#include > > /* Length limits for names and paths, to protect the dynamic linker, > particularly when __libc_enable_secure is active. */ > @@ -92,4 +94,7 @@ call_init_paths (const struct dl_main_state *state) > _dl_init_paths (state->library_path); > } > > +/* Print ld.so usage information and exit. */ > +void _dl_usage (void) attribute_hidden __attribute__ ((__noreturn__)); > + > #endif /* _DL_MAIN */ Why not use C11 _Noreturn? > diff --git a/elf/dl-usage.c b/elf/dl-usage.c > new file mode 100644 > index 0000000000..f3d89d22b7 > --- /dev/null > +++ b/elf/dl-usage.c > @@ -0,0 +1,51 @@ > +/* Print usage information and help for ld.so. > + Copyright (C) 1995-2020 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 > + > +void > +_dl_usage (void) > +{ > + _dl_fatal_printf ("\ > +Usage: ld.so [OPTION]... EXECUTABLE-FILE [ARGS-FOR-PROGRAM...]\n\ > +You have invoked `ld.so', the helper program for shared library executables.\n\ > +This program usually lives in the file `/lib/ld.so', and special directives\n\ > +in executable files using ELF shared libraries tell the system's program\n\ > +loader to load the helper program from this file. This helper program loads\n\ > +the shared libraries needed by the program executable, prepares the program\n\ > +to run, and runs it. You may invoke this helper program directly from the\n\ > +command line to load and run an ELF executable file; this is like executing\n\ > +that file itself, but always uses this helper program from the file you\n\ > +specified, instead of the helper program file specified in the executable\n\ > +file you run. This is mostly of use for maintainers to test new versions\n\ > +of this helper program; chances are you did not intend to run this program.\n\ > +\n\ > + --list list all dependencies and how they are resolved\n\ > + --verify verify that given object really is a dynamically linked\n\ > + object we can handle\n\ > + --inhibit-cache Do not use " LD_SO_CACHE "\n\ > + --library-path PATH use given PATH instead of content of the environment\n\ > + variable LD_LIBRARY_PATH\n\ > + --inhibit-rpath LIST ignore RUNPATH and RPATH information in object names\n\ > + in LIST\n\ > + --audit LIST use objects named in LIST as auditors\n\ > + --preload LIST preload objects named in LIST\n\ > + --argv0 STRING set argv[0] to STRING before running\n"); > +} Ok. > diff --git a/elf/rtld.c b/elf/rtld.c > index c1153cb627..f3e1791e2f 100644 > --- a/elf/rtld.c > +++ b/elf/rtld.c > @@ -1246,31 +1246,7 @@ dl_main (const ElfW(Phdr) *phdr, > /* If we have no further argument the program was called incorrectly. > Grant the user some education. */ > if (_dl_argc < 2) > - _dl_fatal_printf ("\ > -Usage: ld.so [OPTION]... EXECUTABLE-FILE [ARGS-FOR-PROGRAM...]\n\ > -You have invoked `ld.so', the helper program for shared library executables.\n\ > -This program usually lives in the file `/lib/ld.so', and special directives\n\ > -in executable files using ELF shared libraries tell the system's program\n\ > -loader to load the helper program from this file. This helper program loads\n\ > -the shared libraries needed by the program executable, prepares the program\n\ > -to run, and runs it. You may invoke this helper program directly from the\n\ > -command line to load and run an ELF executable file; this is like executing\n\ > -that file itself, but always uses this helper program from the file you\n\ > -specified, instead of the helper program file specified in the executable\n\ > -file you run. This is mostly of use for maintainers to test new versions\n\ > -of this helper program; chances are you did not intend to run this program.\n\ > -\n\ > - --list list all dependencies and how they are resolved\n\ > - --verify verify that given object really is a dynamically linked\n\ > - object we can handle\n\ > - --inhibit-cache Do not use " LD_SO_CACHE "\n\ > - --library-path PATH use given PATH instead of content of the environment\n\ > - variable LD_LIBRARY_PATH\n\ > - --inhibit-rpath LIST ignore RUNPATH and RPATH information in object names\n\ > - in LIST\n\ > - --audit LIST use objects named in LIST as auditors\n\ > - --preload LIST preload objects named in LIST\n\ > - --argv0 STRING set argv[0] to STRING before running\n"); > + _dl_usage (); > > ++_dl_skip_args; > --_dl_argc; > Ok.