Date: Sun, 4 Nov 2018 19:30:39 +0200 From: Daniel Braniss <danny@cs.huji.ac.il> To: Dimitry Andric <dim@FreeBSD.org>, freebsd-hackers@FreeBSD.org Subject: Re: help with dl module and clang Message-ID: <7ACC89D8-ECFF-41D0-AAB4-6D88F1387117@cs.huji.ac.il> In-Reply-To: <20181104172207.GB5335@kib.kiev.ua> 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> <20181104172207.GB5335@kib.kiev.ua>
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> On 4 Nov 2018, at 19:22, Konstantin Belousov <kostikbel@gmail.com> = wrote: >=20 > On Sat, Nov 03, 2018 at 07:31:33PM +0200, Daniel Braniss wrote: >>=20 >>=20 >>> On 3 Nov 2018, at 18:35, Konstantin Belousov <kostikbel@gmail.com> = wrote: >>>=20 >>> On Sat, Nov 03, 2018 at 06:11:19PM +0200, Daniel Braniss wrote: >>>>=20 >>>>=20 >>>>> On 3 Nov 2018, at 17:58, Daniel Braniss <danny@cs.huji.ac.il> = wrote: >>>>>=20 >>>>>=20 >>>>>=20 >>>>>> On 3 Nov 2018, at 17:47, Dimitry Andric <dim@FreeBSD.org> wrote: >>>>>>=20 >>>>>> On 3 Nov 2018, at 15:51, Daniel Braniss <danny@cs.huji.ac.il> = wrote: >>>>>>>=20 >>>>>>> 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. >>>>>>>=20 >>>>>>> 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 =E2=80=A6 >>>>>>> BTW, when linking the main program with cc I get >>>>>>> /usr/bin/ld: warning: cannot find entry symbol = xport-dynamic; defaulting to 0000000000402140 >>>>>>=20 >>>>>> 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. >>>>>>=20 >>>>>=20 >>>>> 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 :-))!!!!! >>>>>=20 >>>>> thanks!!!!!! >>>>>=20 >>>>> and now have to try profiling (gprof) which started this mess, >>>>>=20 >>>>> thanks again!! >>>>>=20 >>>>> danny >>>>>=20 >>>>>=20 >>>>>> I think this will also help with the exporting of the symbols of = your >>>>>> main program. >>>>>>=20 >>>>>> -Dimitry >>>>>>=20 >>>>>=20 >>>> ok, new problem, it also happens with gcc: >>>>=20 >>>> 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. >>=20 >> as far as I can tell, it=E2=80=99s NOT statically linked: >> l >> e-kots-b# ldd /vol/src/libexec/idng/idngd/idngd=20 >> /vol/src/libexec/idng/idngd/idngd: >> libpq.so.5 =3D> /usr/local/lib/libpq.so.5 (0x800932000) >> libcrypto.so.8 =3D> /lib/libcrypto.so.8 (0x800c00000) >> libldap-2.4.so.2 =3D> /usr/local/lib/libldap-2.4.so.2 = (0x801070000) >> libthr.so.3 =3D> /lib/libthr.so.3 (0x8012b7000) >> libintl.so.8 =3D> /usr/local/lib/libintl.so.8 (0x8014df000) >> libssl.so.8 =3D> /usr/lib/libssl.so.8 (0x8016ea000) >> libc.so.7 =3D> /lib/libc.so.7 (0x80195d000) >> liblber-2.4.so.2 =3D> /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 >=20 > I suppose that dlopen(3) is called from the text of the idngd binary ? correct > Put the readelf -a idngd output somewhere. www.cs.huji.ac.il/~danny/idngd.elf.out = <http://www.cs.huji.ac.il/~danny/idngd.elf.out>;
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