Date: Sun, 4 Nov 2018 19:22:07 +0200 From: Konstantin Belousov <kostikbel@gmail.com> To: Daniel Braniss <danny@cs.huji.ac.il> Cc: Dimitry Andric <dim@FreeBSD.org>, freebsd-hackers@FreeBSD.org Subject: Re: help with dl module and clang Message-ID: <20181104172207.GB5335@kib.kiev.ua> In-Reply-To: <FA5207CF-3584-4D4E-A21F-AF76A0207729@cs.huji.ac.il> References: <4B8101F4-9A89-4486-8DF3-93DC799EF6D4@cs.huji.ac.il> <E3B4CDF3-2DE9-4785-963C-9158105C263E@FreeBSD.org> <2E58B6A3-B3E4-4266-9B40-5F3D64433460@cs.huji.ac.il> <08A14290-0A6E-4002-892E-D4254EB23076@cs.huji.ac.il> <20181103163508.GS5335@kib.kiev.ua> <FA5207CF-3584-4D4E-A21F-AF76A0207729@cs.huji.ac.il>
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On Sat, Nov 03, 2018 at 07:31:33PM +0200, Daniel Braniss wrote: > > > > On 3 Nov 2018, at 18:35, Konstantin Belousov <kostikbel@gmail.com> wrote: > > > > On Sat, Nov 03, 2018 at 06:11:19PM +0200, Daniel Braniss wrote: > >> > >> > >>> On 3 Nov 2018, at 17:58, Daniel Braniss <danny@cs.huji.ac.il> wrote: > >>> > >>> > >>> > >>>> On 3 Nov 2018, at 17:47, Dimitry Andric <dim@FreeBSD.org> wrote: > >>>> > >>>> On 3 Nov 2018, at 15:51, Daniel Braniss <danny@cs.huji.ac.il> wrote: > >>>>> > >>>>> I have a program that loads some modules via dlopen(), these modules call some routines > >>>>> which are in the main program, this works when using gcc, but with cc it does not. > >>>>> > >>>>> when compiling the main program I use -export-dynamic, and the modules link fine when compiled with > >>>>> gcc, but when compiling with clang/cc i get dlerror: ...Undefined symbol … > >>>>> BTW, when linking the main program with cc I get > >>>>> /usr/bin/ld: warning: cannot find entry symbol xport-dynamic; defaulting to 0000000000402140 > >>>> > >>>> Instead of using -export-dynamic (which is a linker flag) as a flag to > >>>> cc, try using -Wl,-export-dynamic instead. Now, the linker interprets > >>>> this as the -e flag, which is something totally different. > >>>> > >>> > >>> i had tried that before but i had -WI (upper case i) but re-reading the manual > >>> it should be-Wl (lower case l as in lima :-))!!!!! > >>> > >>> thanks!!!!!! > >>> > >>> and now have to try profiling (gprof) which started this mess, > >>> > >>> thanks again!! > >>> > >>> danny > >>> > >>> > >>>> I think this will also help with the exporting of the symbols of your > >>>> main program. > >>>> > >>>> -Dimitry > >>>> > >>> > >> ok, new problem, it also happens with gcc: > >> > >> when compiling the main program with flag -pg (gprof) > >> dlopen fails with dlerror: Service unavailable > > This means that your binary is linked statically. > > dlopen(3) is not supported for static linking, ld-elf.so.1 is required > > for dynamic loading to work. > > as far as I can tell, it’s NOT statically linked: > l > e-kots-b# ldd /vol/src/libexec/idng/idngd/idngd > /vol/src/libexec/idng/idngd/idngd: > libpq.so.5 => /usr/local/lib/libpq.so.5 (0x800932000) > libcrypto.so.8 => /lib/libcrypto.so.8 (0x800c00000) > libldap-2.4.so.2 => /usr/local/lib/libldap-2.4.so.2 (0x801070000) > libthr.so.3 => /lib/libthr.so.3 (0x8012b7000) > libintl.so.8 => /usr/local/lib/libintl.so.8 (0x8014df000) > libssl.so.8 => /usr/lib/libssl.so.8 (0x8016ea000) > libc.so.7 => /lib/libc.so.7 (0x80195d000) > liblber-2.4.so.2 => /usr/local/lib/liblber-2.4.so.2 (0x801d18000) > e-kots-b# file !$ > file /vol/src/libexec/idng/idngd/idngd > /vol/src/libexec/idng/idngd/idngd: ELF 64-bit LSB executable, x86-64, version 1 (FreeBSD), dynamically linked, interpreter /libexec/ld-elf.so.1, for FreeBSD 11.2 (1102501 <tel:1102501>), FreeBSD-style, not stripped I suppose that dlopen(3) is called from the text of the idngd binary ? Put the readelf -a idngd output somewhere.
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