Hi everyone
I get the error " /usr/bin/ld: .libs/scan_sync_demo: hidden symbol `stat' in /usr/lib64/libc_nonshared.a(stat.oS) is referenced by DSO
/usr/bin/ld: final link failed: Nonrepresentable section on output ",
The immediate cause is my XXX.so reference stat/fstat, but I find stat/fstat is not defined in XXX.so (by ldd –r)。
[.libs]$ldd -r libobapi.so
linux-vdso.so.1 => (0x00007ffff01ff000)
libpthread.so.0 => /lib64/libpthread.so.0 (0x00007fd5ca9fd000)
librt.so.1 => /lib64/librt.so.1 (0x00007fd5ca7f5000)
libdl.so.2 => /lib64/libdl.so.2 (0x00007fd5ca5f1000)
libaio.so.1 => /lib64/libaio.so.1 (0x00007fd5ca3ef000)
libstdc++.so.6 => /usr/lib64/libstdc++.so.6 (0x00007fd5ca0e9000)
libm.so.6 => /lib64/libm.so.6 (0x00007fd5c9e65000)
libc.so.6 => /lib64/libc.so.6 (0x00007fd5c9ad2000)
/lib64/ld-linux-x86-64.so.2 (0x0000003b99400000)
libgcc_s.so.1 => /lib64/libgcc_s.so.1 (0x00007fd5c98bc000)
undefined symbol: stat (./libobapi.so)
undefined symbol: fstat (./libobapi.so)
It is strange, xxx.so references /lib64/libc.so.6, stat/fstat obviously belong libc。But later I realize it is wrong,
[ .libs]$objdump -t /lib64/libc.so.6|grep fstat
0000000000000000 l df *ABS* 0000000000000000 fstatfs64.c
0000000000000000 l df *ABS* 0000000000000000 fstatvfs.c
0000000000000000 l df *ABS* 0000000000000000 fstatvfs64.c
0000003b99cd9eb0 l F .text 0000000000000025 __GI_fstatfs64
0000003b99cd9f70 l F .text 000000000000008c __fstatvfs64
0000003b99cd9eb0 l F .text 0000000000000025 __fstatfs
0000003b99cd9eb0 l F .text 0000000000000025 __GI___fstatfs64
0000003b99cd9eb0 l F .text 0000000000000025 __fstatfs64
0000003b99cd9f70 l F .text 000000000000008c __GI_fstatvfs
0000003b99cd9eb0 l F .text 0000000000000025 __GI_fstatfs
0000003b99cd9eb0 l F .text 0000000000000025 __GI___fstatfs
0000003b99cd9eb0 w F .text 0000000000000025 fstatfs64
0000003b99cd9f70 w F .text 000000000000008c fstatvfs64
0000003b99cd9eb0 w F .text 0000000000000025 fstatfs
0000003b99cd9f70 g F .text 000000000000008c fstatvfs
I can’t find fstat/stat, but __fxstat/__xstat
[.libs]$objdump -t /lib64/libc.so.6|grep xstat
……..
0000003b99cd9d20 g F .text 0000000000000044 __lxstat
0000003b99cd9cd0 g F .text 0000000000000044 __fxstat64
0000003b99cd9cd0 g F .text 0000000000000044 __fxstat
0000003b99cd9d20 g F .text 0000000000000044 __lxstat64
0000003b99cd9c80 g F .text 0000000000000044 __xstat
0000003b99cd9c80 g F .text 0000000000000044 __xstat64
0000003b99cd9e30 g F .text 000000000000004c __fxstatat64
0000003b99cd9e30 g F .text 000000000000004c __fxstatat
Where is fstat/stat? I read glibc source(v2.18), find
/* The `stat', `fstat', `lstat' functions have to be handled special since
even while not compiling the library with optimization calls to these
functions in the shared library must reference the `xstat' etc functions.
We have to use macros but we cannot define them in the normal headers
since on user level we must use real functions. */
#define stat(fname, buf) __xstat (_STAT_VER, fname, buf)
#define lstat(fname, buf) __lxstat (_STAT_VER, fname, buf)
#define __lstat(fname, buf) __lxstat (_STAT_VER, fname, buf)
#define lstat64(fname, buf) __lxstat64 (_STAT_VER, fname, buf)
#define __lstat64(fname, buf) __lxstat64 (_STAT_VER, fname, buf)
#define stat64(fname, buf) __xstat64 (_STAT_VER, fname, buf)
#define fstat64(fd, buf) __fxstat64 (_STAT_VER, fd, buf)
#define __fstat64(fd, buf) __fxstat64 (_STAT_VER, fd, buf)
#define fstat(fd, buf) __fxstat (_STAT_VER, fd, buf)
#define __fstat(fd, buf) __fxstat (_STAT_VER, fd, buf)
#define __fstatat(dfd, fname, buf, flag) \
__fxstatat (_STAT_VER, dfd, fname, buf, flag)
#define __fstatat64(dfd, fname, buf, flag) \
__fxstatat64 (_STAT_VER, dfd, fname, buf, flag)
What does the comment means? I just know stat/fstat is macro from it.
My question is, why does stat/fstat appeared in xxx.so, why not replaced by __xstat/__fxstat in pre_process.
Here is a simple example.
Libfile.cpp
#include <sys/stat.h>
#include <sys/types.h>
#include <unistd.h>
void func()
{
fstat(0,0);
stat(0, 0);
}
[test3]$g++ -fPIC libfile.cpp -c
test3]$objdump -t libfile.o
libfile.o: file format elf64-x86-64
SYMBOL TABLE:
0000000000000000 l df *ABS* 0000000000000000 libfile.cpp
0000000000000000 l d .text 0000000000000000 .text
0000000000000000 l d .data 0000000000000000 .data
0000000000000000 l d .bss 0000000000000000 .bss
0000000000000000 l d .data.DW.ref.__gxx_personality_v0 0000000000000000 .data.DW.ref.__gxx_personality_v0
0000000000000000 l d .note.GNU-stack 0000000000000000 .note.GNU-stack
0000000000000000 l d .eh_frame 0000000000000000 .eh_frame
0000000000000000 l d .comment 0000000000000000 .comment
0000000000000000 l d .group 0000000000000000 .group
0000000000000000 g F .text 0000000000000024 _Z4funcv
0000000000000000 w O .data.DW.ref.__gxx_personality_v0 0000000000000008 .hidden DW.ref.__gxx_personality_v0
0000000000000000 *UND* 0000000000000000 _GLOBAL_OFFSET_TABLE_
0000000000000000 *UND* 0000000000000000 fstat
0000000000000000 *UND* 0000000000000000 stat
0000000000000000 *UND* 0000000000000000 __gxx_personality_v0
[jienan.zjn@OceanBase036005 test3]$g++ -shared libfile.o -o libfile.so
[jienan.zjn@OceanBase036005 test3]$objdump -t libfile.so |grep stat
0000000000000690 l F .text 000000000000000f __fstat
0000000000000680 l F .text 0000000000000010 __stat
0000000000000680 l F .text 0000000000000010 stat
0000000000000690 l F .text 000000000000000f fstat
0000000000000000 F *UND* 0000000000000000 __xstat@@GLIBC_2.2.5
0000000000000000 F *UND* 0000000000000000 __fxstat@@GLIBC_2.2.5
In this example, stat/fstat is defined in libfile.so. don’t look like macro. I don’t where I went wrong. Before emailing, I search similar questions, but I don’t get what I wanted.
What more strange is
[jienan.zjn@OceanBase036005 test3]$g++ -fPIC libfile.cpp -c -O
[jienan.zjn@OceanBase036005 test3]$objdump -t libfile.o
libfile.o: file format elf64-x86-64
SYMBOL TABLE:
0000000000000000 l df *ABS* 0000000000000000 libfile.cpp
0000000000000000 l d .text 0000000000000000 .text
0000000000000000 l d .data 0000000000000000 .data
0000000000000000 l d .bss 0000000000000000 .bss
0000000000000000 l d .data.DW.ref.__gxx_personality_v0 0000000000000000 .data.DW.ref.__gxx_personality_v0
0000000000000000 l d .note.GNU-stack 0000000000000000 .note.GNU-stack
0000000000000000 l d .eh_frame 0000000000000000 .eh_frame
0000000000000000 l d .comment 0000000000000000 .comment
0000000000000000 l d .group 0000000000000000 .group
0000000000000000 g F .text 0000000000000031 _Z4funcv
0000000000000000 w O .data.DW.ref.__gxx_personality_v0 0000000000000008 .hidden DW.ref.__gxx_personality_v0
0000000000000000 *UND* 0000000000000000 _GLOBAL_OFFSET_TABLE_
0000000000000000 *UND* 0000000000000000 __fxstat
0000000000000000 *UND* 0000000000000000 __xstat
stat/fstat disappeared.
Appreciate your reply!
