linking against libebb

[Christian Ost]

Hi,

i am experiencing some strange issues when trying to link against
libebb:

(1) linking against libebb.0.1.so (BTW please change the name to
libebb.so-0.1)

gcc -o copperwire copperwire.o -lebb
(created a symlink /usr/lib/libebb.so => /usr/lib/libebb.0.1.so)
=> no error output, however

`ldd -r copperwire` gives

undefined symbol: ebb_server_init (./copperwire)
linux-vdso.so.1 => (0x00007fff1ebfe000)
libptr_array-0.1.so => /usr/lib/libptr_array-0.1.so
(0x00007fb01670d000)
libc.so.6 => /lib/libc.so.6 (0x00007fb0163ab000)
libev.so.3 => /usr/lib/libev.so.3 (0x00007fb01619f000)
/lib64/ld-linux-x86-64.so.2 (0x00007fb01690f000)
libm.so.6 => /lib/libm.so.6 (0x00007fb015f1e000)
librt.so.1 => /lib/librt.so.1 (0x00007fb015d15000)
libpthread.so.0 => /lib/libpthread.so.0 (0x00007fb015af9000)

(if i do the linking without -lebb, i get the undefined symbol error -
so somehow the linker
believes to link against libebb, but does not actually do this?)

So I had a look at the example:

make examples gives me:

examples/hello_world.c:11: Warnung: »c« definiert, aber nicht
verwendet
cc -L/usr/lib -lev -L/home/cost/local/libev/lib -L/usr/lib -lgnutls -L/
home/cost/local/libeio/lib -leio -Wall -I. -I/usr/include -I/home/cost/
local/libev/include -I/usr/include -I/home/cost/local/libeio/include -
DVERSION=\"0.1\" -DHAVE_GNUTLS -DHAVE_EIO -lev -o examples/hello_world
examples/hello_world.o libebb.a
cc: examples/hello_world.o: No such file or directory

so there seems to be some error in your Makefile, however saw you
tried linking
against libebb.a and tried this, too:

(2) linking against libebb.a (using -lgnutls -lev)

linking succeeds, but when trying to run the resulting executable I
get:

*** stack smashing detected ***: /home/cost/kupferwerk/copperwire/
debug/./src/copperwire terminated
======= Backtrace: =========
/lib/libc.so.6(__fortify_fail+0x37)[0x7f2a7171f607]
/lib/libc.so.6(__fortify_fail+0x0)[0x7f2a7171f5d0]
/home/cost/kupferwerk/copperwire/debug/./src/copperwire[0x401763]
/lib/libc.so.6(__libc_start_main+0xf4)[0x7f2a716501c4]
/home/cost/kupferwerk/copperwire/debug/./src/copperwire[0x401669]
======= Memory map: ========
00400000-0040f000 r-xp 00000000 08:04
811354 /home/cost/kupferwerk/copperwire/
debug/src/copperwire
0060e000-0060f000 rw-p 0000e000 08:04
811354 /home/cost/kupferwerk/copperwire/
debug/src/copperwire
0060f000-00630000 rw-p 0060f000 00:00
0 [heap]
7f2a70506000-7f2a70513000 r-xp 00000000 08:04
1392704 /lib/libgcc_s.so.1
7f2a70513000-7f2a70713000 ---p 0000d000 08:04
1392704 /lib/libgcc_s.so.1
7f2a70713000-7f2a70714000 rw-p 0000d000 08:04
1392704 /lib/libgcc_s.so.1
7f2a70714000-7f2a7072a000 r-xp 00000000 08:04
1392757 /lib/libpthread-2.7.so
7f2a7072a000-7f2a7092a000 ---p 00016000 08:04
1392757 /lib/libpthread-2.7.so
7f2a7092a000-7f2a7092c000 rw-p 00016000 08:04
1392757 /lib/libpthread-2.7.so
7f2a7092c000-7f2a70930000 rw-p 7f2a7092c000 00:00 0
7f2a70930000-7f2a70933000 r-xp 00000000 08:04
1392708 /lib/libgpg-error.so.0.3.0
7f2a70933000-7f2a70b32000 ---p 00003000 08:04
1392708 /lib/libgpg-error.so.0.3.0
7f2a70b32000-7f2a70b33000 rw-p 00002000 08:04
1392708 /lib/libgpg-error.so.0.3.0
7f2a70b33000-7f2a70b3b000 r-xp 00000000 08:04
1392763 /lib/librt-2.7.so
7f2a70b3b000-7f2a70d3a000 ---p 00008000 08:04
1392763 /lib/librt-2.7.so
7f2a70d3a000-7f2a70d3c000 rw-p 00007000 08:04
1392763 /lib/librt-2.7.so
7f2a70d3c000-7f2a70dbc000 r-xp 00000000 08:04
1392716 /lib/libm-2.7.so
7f2a70dbc000-7f2a70fbb000 ---p 00080000 08:04
1392716 /lib/libm-2.7.so
7f2a70fbb000-7f2a70fbd000 rw-p 0007f000 08:04
1392716 /lib/libm-2.7.so
7f2a70fbd000-7f2a71009000 r-xp 00000000 08:04
1392706 /lib/libgcrypt.so.11.2.3
7f2a71009000-7f2a71208000 ---p 0004c000 08:04
1392706 /lib/libgcrypt.so.11.2.3
7f2a71208000-7f2a7120b000 rw-p 0004b000 08:04
1392706 /lib/libgcrypt.so.11.2.3
7f2a7120b000-7f2a71221000 r-xp 00000000 08:04
3074389 /usr/lib/libz.so.1.2.3.3
7f2a71221000-7f2a71421000 ---p 00016000 08:04
3074389 /usr/lib/libz.so.1.2.3.3
7f2a71421000-7f2a71422000 rw-p 00016000 08:04
3074389 /usr/lib/libz.so.1.2.3.3
7f2a71422000-7f2a71432000 r-xp 00000000 08:04
3074313 /usr/lib/libtasn1.so.3.0.12
7f2a71432000-7f2a71631000 ---p 00010000 08:04
3074313 /usr/lib/libtasn1.so.3.0.12
7f2a71631000-7f2a71632000 rw-p 0000f000 08:04
3074313 /usr/lib/libtasn1.so.3.0.12
7f2a71632000-7f2a7178a000 r-xp 00000000 08:04
1392679 /lib/libc-2.7.so
7f2a7178a000-7f2a7198a000 ---p 00158000 08:04
1392679 /lib/libc-2.7.so
7f2a7198a000-7f2a7198d000 r--p 00158000 08:04
1392679 /lib/libc-2.7.so
7f2a7198d000-7f2a7198f000 rw-p 0015b000 08:04
1392679 /lib/libc-2.7.so
7f2a7198f000-7f2a71994000 rw-p 7f2a7198f000 00:00 0
7f2a71994000-7f2a719a0000 r-xp 00000000 08:04
3075145 /usr/lib/libev.so.3.0.0
7f2a719a0000-7f2a71b9f000 ---p 0000c000 08:04
3075145 /usr/lib/libev.so.3.0.0
7f2a71b9f000-7f2a71ba0000 rw-p 0000b000 08:04
3075145 /usr/lib/libev.so.3.0.0
7f2a71ba0000-7f2a71c1b000 r-xp 00000000 08:04
3073667 /usr/lib/libgnutls.so.13.9.1
7f2a71c1b000-7f2a71e1a000 ---p 0007b000 08:04
3073667 /usr/lib/libgnutls.so.1Aborted

Would be nice, if someone had a suggestion how to solve this
problem...

Thank you very much!


Christian

[Christian Ost]

ok, the stack smashing error was due to a programming mistake on
my behalf, the second configuration actually works.

However two poitns remain:

What could cause the strange behaviour in (1)?

Please update your Makefile to place hello_world.o
in ./examples/ instead of .

Thanks!


Christian

[ry dahl]

Hey Christian,

Thanks for looking at this. These linking problems are always a pain
for me. I've updated the Makefile - and things seem to be working
okay. I'm still have a strange issue with callbacks linked against the
so. I'll try to fix that soon.

I updated the make install/uninstall tasks. So you should be able to
use that. For the moment link against the .a if you're experiencing my
callback problem too.

ry