emacs a.out file, self-generated by emacs's "unexec" function in
"unexsunos4.c", is invalid. In particular, its "_end" symbol has
the wrong value. The dynamic linker was using the value of that
symbol to initialize its sbrk break level.
The workaround is to peek at the executable's a.out header in
memory, and calculate what "_end" should be based on the segment
sizes.
I will work out a fix for emacs and send it to the FSF. This
dynamic linker workaround is still worthwhile, if only to avoid
forcing all emacs users to build a new version.
Note: xemacs gives a bogus warning at startup, for related reasons.
The warning is harmless and can safely be ignored. I will send a
patch to the xemacs maintainers to get rid of it, and meanwhile
add a patch file to our port.
things so that it uses the same malloc as is used by the program
being executed. This has several advantages, the big one being
that you can now debug core dumps from dynamically linked programs
and get useful information out of them. Until now, that didn't
work. The internal malloc package placed the tables describing
the loaded shared libraries in a mapped region of high memory that
was not written to core files. Thus the debugger had no way of
determining what was loaded where in memory. Now that the dynamic
linker uses the application's malloc package (normally, but not
necessarily, the system malloc), its tables end up in the regular
heap area where they will be included in core dumps. The debugger
now works very well indeed, thank you very much.
Also ...
Bring the program a little closer to conformance with style(9).
There is still a long way to go.
Add minimal const correctness changes to get rid of compiler warnings
caused by the recent const changes in <dlfcn.h> and <link.h>.
Improve performance by eliminating redundant calculations of symbols'
hash values.
Implemented reading of %fs and %gs from core files.
Print weird floating point values better. We have to convert long
doubles to doubles here because of limitations and bugs in printf()
and floatformat_to_double() (long doubles aren't really supported
and naive converion to double causes exceptions). Conversion loses
information about weird formats (everything becomes a quiet NaN),
and printf() doesn't know about different types of NaNs anyway.
can get their rights as well. ;-) The default remains, of course, Taylor
config.
Demanded by: some people on -hackers
I think this is safe enough to go into RELENG_2_2 as well, if there's
demand.
plain 0 should be used. This happens to work because we #define
NULL to 0, but is stylistically wrong and can cause problems
for people trying to port bits of code to other environments.
PR: 2752
Submitted by: Arne Henrik Juul <arnej@imf.unit.no>
Bring the style of sods.c into better conformance. Add code to
print the contents of each datum being relocated. Correct the logic
that distinguishes between programs, shared libraries, and object
files. Make the entire program "-Wall" clean.
