linux_core_dumper: support NT_SIGINFO for reading crashing address

The current core dumper only parses NT_PRSTATUS notes.  With signal
details, this note only includes three fields: signo, code, and errno.
We set exception_code to signo and exception_flag to code.  The errno
value isn't set by the kernel, so there's no need to save it.

However, we never fill in exception_address which means all converted
crashes look like they happen at address 0.  This implies a NULL jump
which is usually not the case, so it's just confusing.  The prstatus
structure doesn't offer anything directly that tracks this.

Starting with linux-3.7, the kernel writes out the full siginfo
structure in the NT_SIGINFO note.  So lets support that to pull out
si_addr which, for a bunch of common signals, is the value we want in
exception_address.

The size of the siginfo_t structure should be locked to 128 bytes at
build time for all architectures, so this should hopefully be stable.

Bug: google-breakpad:790
Change-Id: I458bad4787b1a8b73fad8fe068e9f23bec957599
Reviewed-on: https://chromium-review.googlesource.com/c/1497661
Reviewed-by: Mark Mentovai <mark@chromium.org>

0 files changed, 0 insertions, 0 deletions