it actually fixes a problem:
When /bin/sh gets a SIGSEGV, its signal handler calls brk and the offending
instruction is retried. Usually it gets another SIGSEGV, and things loops
until it pases without the SIGSEGV. This is the normal mode of operation, and
it can be reproduced on IRIX by a 10kB shell script starting by echo /*
However... the signal handler checks for BADVADDR in the saved registers
in struct sigcontext. If it does not find it, it gives up and exit instead
of retrying. Filling the field enables us to carry on normal operation
(which is to get dozens of SIGSEGV) instead of getting a failure at the
first SIGSEGV.
Fix an obvious bug in the 64-bit PLT fixup: the SLLX was by 12 bits, when it
should be 32.
Fix what *appear* to be two bugs in the >32768 PLT entry stub:
* One division was wrong (/14 rather than /24).
* We need to subtract 1048576 (to make the offset relative to the beginning of
the upper section), not add it.
This path is still untested, and buggy.
way we don't have to worry about malloc() failure. Also closes
a memory leak since vis_user was never free()d. Lack of malloc()
checking pointed out by Peter Werner.
from openbsd
symbols in the global part of the symbol table, use the updated GOT entry
rather than doing a lookup. (This provides the same effect as `-z combreloc'
on other platforms -- at most one lookup is done per symbol.)
Unfortunately, it is necessary to turn off lazy binding on MIPS. As the
comment says:
* XXX DANGER WILL ROBINSON!
* You might think this is stupid, as it intentionally
* defeats lazy binding -- and you'd be right.
* Unfortunately, for lazy binding to work right, we
* need to a way to force the GOT slots used for
* function pointers to be resolved immediately. This
* is supposed to be done automatically by the linker,
* by not outputting a PLT slot and setting st_value
* to 0, but GNU ld does not do so reliably.
