Date: Fri, 14 Jul 2006 18:51:08 +0200 From: Roland Dittel <Roland.Dittel@web.de> To: hackers@freebsd.org Subject: dlsym() on implicit loaded symbols Message-ID: <62d3f75eb4400604406fdea341d91e41@web.de>
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Hi all,
We have a issue with dlsym() on symbols imported by a library that was
loaded with dlopen(). Our code loads the libssl with dlopen() and then
do a dlsym() on several symbols. This works for all symbols exported by
libssl itself but fails for symbols exported by libcrypto. Libssl is
dynamically linked to libcrypto and should be loaded for libssl. I did
a truss and the FreeBSD loader loads libcrypto but does not read
anything from the file pointer.
This is the truss output:
<snip>
access("/prod/lib/fbsd-i386/libssl.so",0) = 0 (0x0)
open("/prod/lib/fbsd-i386/libssl.so",0x0,027757760020) = 3 (0x3)
fstat(3,0xbfbfe010) = 0 (0x0)
fstatfs(0x3,0xbfbfde30) = 0 (0x0)
read(3,"ELF ",4096) = 4096 (0x1000)
mmap(0x0,229376,(0x5)PROT_READ|PROT_EXEC,(0x20002)MAP_NOCORE|MAP_PRIVATE
,3,0x0) = 674971648 (0x283b4000)
mprotect(0x283e7000,4096,(0x7)PROT_READ|PROT_WRITE|PROT_EXEC) = 0 (0x0)
mprotect(0x283e7000,4096,(0x5)PROT_READ|PROT_EXEC) = 0 (0x0)
mmap(0x283e8000,16384,(0x3)PROT_READ|PROT_WRITE,(0x12)MAP_FIXED|MAP_PRIV
ATE,3,0x33000) = 675184640 (0x283e8000)
close(3) = 0 (0x0)
access("/prod/lib/fbsd-i386/libcrypto.so.0.9.8",0) = 0 (0x0)
open("/prod/lib/fbsd-i386/libcrypto.so.0.9.8",0x0,05005664564) = 3 (0x3)
fstat(3,0xbfbfdfe0) = 0 (0x0)
close(3) = 0 (0x0)
mmap(0x0,5528,(0x3)PROT_READ|PROT_WRITE,(0x1000)MAP_ANON,-1,0x0) =
675201024 (0x283ec000)
munmap(0x283ec000,5528) = 0 (0x0)
</snip>
On solaris, linux and irix the same code works fine and the libcrypto
symbols are implicit loaded and usable. Does anyone know why FreeBSD
behaves differently that other Unixes?
Thanks,
Roland
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