Embeds the address of g_crashpad_info into a .note section (which is
readable by the generic code to read notes in ElfImageReader).
Unfortunately because the note section is in libclient.a, it would
normally be dropped at link time. To avoid that, GetCrashpadInfo() has
a reference *back* to that section, which in turn forces the linker to
include it, allowing the note reader to find it at runtime.
Previously, it was necessary to have the embedder of "client" figure out
how to cause `g_crashpad_info` to appear in the final module's dynamic
symbol table. With this new approach, there's no manual configuration
necessary, as it's not necessary for the symbol to be exported.
This is currently only implemented in the Linux module reader (and I
believe the current set of enabled tests aren't exercising it?) but it
will also be done this way for the Fuchsia implementation of
ModuleSnapshot.
Bug: crashpad:196
Change-Id: I599db5903bc98303130d11ad850ba9ceed3b801a
Reviewed-on: https://chromium-review.googlesource.com/912284
Commit-Queue: Scott Graham <scottmg@chromium.org>
Reviewed-by: Mark Mentovai <mark@chromium.org>
Reviewed-by: Joshua Peraza <jperaza@chromium.org>
Without the section headers for the symbol table, there's no direct way
to calculate the number of entries in the table.
DT_HASH and DT_GNU_HASH are auxiliary tables that are designed to make
symbol lookup faster. DT_HASH is the original and is theoretically
mandatory. DT_GNU_HASH is the new-and-improved, but is more complex.
In practice, however, an Android build (at least vs. API 16) has only
DT_HASH, and not DT_GNU_HASH, and a Fuchsia build has only DT_GNU_HASH
but not DT_HASH. So, both are tried.
This change does not actually use the data in these tables to improve
the speed of symbol lookup, but instead only uses them to correctly
terminate the linear search.
DT_HASH contains the total number of symbols in the symbol table fairly
directly because there is an entry for each symbol table entry in the
hash table, so the number is the same.
DT_GNU_HASH regrettably does not. Instead, it's necessary to walk the
buckets and chain structure to find the largest entry.
DT_GNU_HASH doesn't appear in any "real" documentation that I'm aware
of, other than the binutils code (at least as far as I know). Some
more-and-less-useful references:
- https://flapenguin.me/2017/04/24/elf-lookup-dt-hash/
- https://flapenguin.me/2017/05/10/elf-lookup-dt-gnu-hash/
- http://deroko.phearless.org/dt_gnu_hash.txt
- https://sourceware.org/ml/binutils/2006-10/msg00377.html
Change-Id: I7cfc4372f29efc37446f0931d22a1f790e44076f
Bug: crashpad:213, crashpad:196
Reviewed-on: https://chromium-review.googlesource.com/876879
Commit-Queue: Scott Graham <scottmg@chromium.org>
Reviewed-by: Mark Mentovai <mark@chromium.org>
Reviewed-by: Joshua Peraza <jperaza@chromium.org>
Switches from test::Multiprocess to test::MultiprocessExec for
ElfImageReader.OneModuleChild.
Uses the new child process launching, and passes the address of libc and
the address of getpid from the child to parent, rather than assuming the
values will be the same in both processes.
And, enables the test on Fuchsia since it now works.
Bug: crashpad:196, crashpad:215
Change-Id: I3650c16c4fccfe9c1e4147192fdc88b997460060
Reviewed-on: https://chromium-review.googlesource.com/887373
Commit-Queue: Scott Graham <scottmg@chromium.org>
Reviewed-by: Mark Mentovai <mark@chromium.org>
Switches from test::Multiprocess to test::MultiprocessExec for
ElfImageReader.MainExecutableChild.
Uses the new child process launching, and passes the expected symbol
address from the child to the parent, rather than assuming the value
will be the same in both processes.
And, enables the test on Fuchsia since it now works.
Bug: crashpad:196, crashpad:215
Change-Id: I3b43407b6584275d61bedc9c13d1625b950fc23b
Reviewed-on: https://chromium-review.googlesource.com/884993
Commit-Queue: Scott Graham <scottmg@chromium.org>
Reviewed-by: Mark Mentovai <mark@chromium.org>
(Still need to avoid fork()-dependence for the non-self tests.)
Bug: crashpad:196
Change-Id: Ib34fe33c7ec295881c1f555995072d9ff742647f
Reviewed-on: https://chromium-review.googlesource.com/876650
Reviewed-by: Joshua Peraza <jperaza@chromium.org>
Reviewed-by: Mark Mentovai <mark@chromium.org>
Commit-Queue: Scott Graham <scottmg@chromium.org>
The dynamic array reader should treat data as unsigned when initially
reading values from the array to prevent premature sign-extension. The
glibc and traditional android headers define d_val using Elf32_Word, an
unsigned type. linux/elf.h, used by unified android headers, defines
d_val using Elf32_Sword, a signed type. Use d_ptr instead since it's
always an unsigned type.
Bug: crashpad:30
Change-Id: Ie8e88941fefc7075621aefe226fdba33b1f6129c
Reviewed-on: https://chromium-review.googlesource.com/847818
Commit-Queue: Joshua Peraza <jperaza@chromium.org>
Reviewed-by: Mark Mentovai <mark@chromium.org>
Only a Linux implementation for now, but similar code for other
OSes can move behind it in the future.
Bug: crashpad:196
Change-Id: I05966db1599a9cac3146d2a3d964e7ad8629d616
Reviewed-on: https://chromium-review.googlesource.com/685408
Reviewed-by: Mark Mentovai <mark@chromium.org>
Commit-Queue: Dave Bort <dbort@google.com>
A step towards making these files usable by non-Linux systems.
Bug: crashpad:196
Change-Id: I71323b29e46208b3992055722e4622d79409c44c
Reviewed-on: https://chromium-review.googlesource.com/685406
Commit-Queue: Dave Bort <dbort@google.com>
Reviewed-by: Mark Mentovai <mark@chromium.org>
A step towards making these files usable by non-Linux systems.
Bug: crashpad:196
Change-Id: I2497fd7e3bcb5390ae1e6ae22902ab6f56b59dff
Reviewed-on: https://chromium-review.googlesource.com/685405
Reviewed-by: Joshua Peraza <jperaza@chromium.org>
Commit-Queue: Dave Bort <dbort@google.com>
A step towards making these files usable by non-Linux systems.
Bug: crashpad:196
Change-Id: I1dc4304b1376a3a5e45228cf40b23f0367d3efa8
Reviewed-on: https://chromium-review.googlesource.com/685404
Commit-Queue: Dave Bort <dbort@google.com>
Reviewed-by: Joshua Peraza <jperaza@chromium.org>
Reviewed-by: Mark Mentovai <mark@chromium.org>
