Hi,
It turns out the undefined fstat symbol problem can be traced to
something going wrong with earlier build of newt. As you can see,
libnewt.so was providing the fstat symbol:
[EMAIL PROTECTED]:/home/scsi/dhd/src/debian/boot-floppies/utilities/dbootstrap$
objdump --dynamic-syms /usr/lib/libnewt.so | grep fstat
0000000000018860 w DF .text 0000000000000000 Base 0x88 fstat
0000000000018860 g DF .text 0000000000000038 Base 0x88 __fstat
[EMAIL PROTECTED]:~$ objdump --dynamic-syms /usr/lib/libnewt.so | grep fstat
0000f14c w DF .text 00000028 Base fstat
0000f14c g DF .text 00000028 Base __fstat
That version of libnewt0 will break library reduction if you compile
dbootstrap against it, because:
1) libloadtrm.a is compiled without -O and thus depends on fstat
(fstat is inlined).
2) dbootstrap inherits an undefined fstat symbol from libloadtrm.a
(which is also not compiled with -O)
3) The reduced version of libnewt.so that ends up on the root.bin disk
doesn't provide the symbol (as well it shouldn't :P).
4) libc.so.6.1 doesn't provide fstat either.
This may be indicative of a bug in glibc or gcc (take your pick,
they're all broken at one point or another it seems...) - the
changelog indicates that libnewt0 was never compiled with optimization
before 0.50-6.
Specifically it seems that if you have a program that uses fstat() and
is compiled without optimization, that links with a library that uses
fstat() and was compiled without optimization, and then the library is
recompiled with optimization, the aforementioned program will no
longer work.
Here's a demonstration:
/* begin fstattest.c */
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>
int main()
{
int fd;
struct stat buf;
fd = open("foobar", O_RDWR | O_CREAT, 0644);
if (fd < 0) {
perror("foobar");
return 1;
}
mystat(fd, &buf);
fstat(fd, &buf);
return 0;
}
/* end fstattest.c */
/* begin libfstattest.c */
#include <sys/stat.h>
int mystat(int fd, struct stat * buf)
{
return fstat(fd, buf);
}
/* end libfstattest.c
Now, observe:
$ gcc -shared -o libfstattest.so libfstattest.c
$ objdump --dynamic-syms libfstattest.so | grep fstat
libfstattest.so: file format elf32-i386
000007b4 w DF .text 00000028 Base fstat
000007b4 g DF .text 00000028 Base __fstat
$ gcc -o fstattest fstattest.c -L. -Wl,-rpath -Wl,`pwd` -lfstattest
$ nm fstattest | grep fstat
U fstat
$ ./fstattest
$ gcc -shared -o libfstattest.so -O libfstattest.c
$ objdump --dynamic-syms libfstattest.so | grep fstat
libfstattest.so: file format elf32-i386
$ ./fstattest
./fstattest: error in loading shared libraries: ./fstattest: undefined symbol:
fstat
--
David Huggins-Daines, Senior Linux Consultant, Linuxcare, Inc.
613.562.1239 desk, 613.223.0225 mobile [EMAIL PROTECTED],
http://www.linuxcare.com/
Linuxcare. Support for the revolution.
