The APT problem

[Matthias Klose <doko@cs.tu-berlin.de>]

I don´t know how to solve this problem. The best thing would be to
link apt and dpkg with a static libstdc++, so that these problems
don´t appear again in the next transition from potato to potato2000.

What we should do for potato: ensure that no important/required
package and no other library (dev package) depends on the old
libstdc++2.9.

I am in vacations until 5. July, so somebody else should inform the
maintainers and then file bug reports. This needs to be done for all
architectures that recently switched to libc6.1 (ix86, ... ?)

	Matthias


Richard Braakman writes:
 > When glibc 2.1 was introduced in potato, apt stopped working.  Recompiling
 > fixed it, but I figured this indicated a bug in the compat code, so today
 > I found time to investigate it.  Jason Gunthorpe had provided me with
 > a test case:
 > 
 > #include <iostream>
 > #include <fstream>
 > 
 > void die(const char *S)
 > {
 >    cerr << S << endl;
 >    exit(1);
 > }
 > 
 > int main(int argc,const char *argv[])
 > {
 >    ifstream F(argv[1],ios::in | ios::nocreate);
 > 
 >    if (!F != 0)
 >       die("!F #1");
 >    
 >    streampos Off = F.tellg();
 >    if (!F != 0)
 >       die("!F #2");
 >    
 >    return 0;
 > }
 > 
 > (This has to be run with the name of an existing file as argument.)
 > 
 > When run on a glibc2.1 system, a version compiled with libstdc++2.9
 > will die with "!F #2".  A version compiled with libstdc++2.9-glibc2.1
 > will exit successfully.
 > 
 > The problem turns out to be rather simple.  istream:tellg() contains
 > this code:
 > 
 > streampos istream::tellg()
 > {
 > #if 0
 >     streampos pos = _strbuf->pubseekoff(0, ios::cur, ios::in);
 > #else
 >     streampos pos = _IO_seekoff (_strbuf, 0, _IO_seek_cur, _IOS_INPUT);
 > #endif
 >     if (pos == streampos(EOF))
 >         set(ios::badbit);
 >     return pos;
 > }
 > 
 > (This is taken from egcs 1.1.2/libio, a different version than what
 > generated libstdc++2.9, but I can tell from the disassembly that the
 > significant part didn't change.)
 > 
 > This code calls _IO_seekoff directly, expecting that it takes a 32-bit
 > offset.  But _IO_seekoff in glibc2.1 takes a 64-bit offset, and ends
 > up trying to seek to 0x100000000 and failing.
 > 
 > egcs's libio appears to be full of references to glibc's libio.
 > I checked some others at random (_IO_proc_open, _IO_file_close,
 > _IO_adjust_column), and found that filebuf::seekoff probably
 > has the same problem when it calls _IO_file_seekoff, because both
 > _IO_old_file_seekoff and _IO_new_file_seekoff now take a 64-bit offset.
 > 
 > Richard Braakman