dlsym() on implicit loaded symbols

Roland Dittel Roland.Dittel at web.de
Fri Jul 14 16:51:17 UTC 2006

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:
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)
,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)
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)

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?


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