On Mon, Apr 5, 2010 at 7:03 AM, Konstantin Belousov
<address@hidden> wrote:
It shall not appear in config.h. What I did is created a macro that
accept a list of PTRACE_* or PT_* identifiers and generates proper
AC_CHECK_DECLS() calls. The individual HAVE_DECL_PTRACE_something or
HAVE_DECL_PT_something defines are still there.
Compilation fails on Linux as follows:
ptrace/_UPT_access_fpreg.c:104:2: error: #error Fix me
make[2]: *** [ptrace/_UPT_access_fpreg.o] Error 1
i.e. HAVE_DECL_PTRACE_* doesn't seem to be defined anywhere.
After I saw your reorganisation for sigframe handling code, I think
that the similar approach may work well there too.
There may be some opportunities for code sharing between OSes with common roots. So I'd like to defer code reorganization for now.
Could you move the get_scratch_loc() code to OS specific files as well? I can help test on Linux once you're done.
Some more thoughts about the freebsd port:
* dl_iterate_phdr() is not async signal safe on linux (it takes some libdl internal locks). So it's unsafe to call from libunwind. But we still do, because there is no better alternative. Is this the case for FreeBSD as well?
* cursor->validate implementation
libunwind uses msync() which is not bulletproof i.e. it's not directly equivalent to access_ok(VERIFY_READ,...) in the kernel. Does FreeBSD have a better alternative?
If there are libc interfaces to enumerate valid stack addresses, the validation can be implemented as an address range check.
-Arun