Even 64-bit Mach-O (MH_MAGIC_64 = 0xfeedfacf) is not a fully 64-bit file
format. File offsets in sections are stored in 32-bit fields, with
Mach-O writers typically truncating offsets too large to fit to just
their low 32 bits. When a section begins at a file offset >= 4GB,
dump_syms would produce an error such as:
Google Chrome Framework.dSYM/Contents/Resources/DWARF/Google Chrome Framework: the section '__apple_names' in segment '__DWARF' claims its contents lie outside the segment's contents
As a workaround, this implements the strategy I first described in
https://crbug.com/940823#c22.
Segment file offsets are stored in 64-bit fields. Because segments
contain sections and must load contiguously, it’s possible to infer a
section’s actual offset by computing its load address relative to its
containing segment’s load address, and treating this as an offset into
the containing segment’s file offset. For safety, this is only done for
64-bit segments (LC_SEGMENT_64) where the 32-bit section offset stored
in the Mach-O file is equal to the low (truncated) 32 bits of the
section offset recomputed per the above strategy.
Beware that this does not provide full “large file” support for 64-bit
Mach-O files. There are other file offsets within Mach-O files aside
from section file offsets that are stored in 32-bit fields even in the
64-bit format, including offsets to symbol table data (LC_SYMTAB and
LC_DYSYMTAB). No attempt is made to recover correct file offsets for
such data because, at present, such data is always stored by dsymutil
near the beginning of .dSYM files, within the first 4GB. If it becomes
necessary to address these other offsets, it should be possible to
recover these offsets by reference to the __LINKEDIT segment that
normally contains them, provided that __LINKEDIT doesn’t span more than
4GB, according to the strategy discussed at the bottom of
https://crbug.com/940823#c22.
Although this is sufficient to allow dump_syms to interpret Chromium
.dSYM files that exceed 4GB, be warned that these Mach-O files are still
technically malformed, and most other tools that consume Mach-O files
will continue to have difficulties interpreting these large files.
As further warning, note that should any individual DWARF section exceed
4GB, internal section offsets will be truncated irrecoverably, unless
and until the toolchain implements support for DWARF64.
https://bugs.llvm.org/show_bug.cgi?id=14969
With this change, dump_syms is able to correctly recover file offsets
from and continue processing a .dSYM file with length 4530593528
(4321MB), whose largest section (__DWARF,__debug_info = .debug_info) has
size 0x8d64c0b8 (2262MB), and which contains four sections (starting
with __DWARF,__apple_names) beginning at file offsets >= 4GB.
Bug: chromium:940823, chromium:946404
Change-Id: I23f5f3b07773fa2f010204d5bb53b6fb1d4926f7
Reviewed-on: https://chromium-review.googlesource.com/c/breakpad/breakpad/+/1541830
Reviewed-by: Robert Sesek <rsesek@chromium.org>
Reviewed-by: Mike Frysinger <vapier@chromium.org>
If the kernel/C library headers are old, they might not have the
fields needed for SIGSYS decoding. Add ifdef checks for that and
skip the logic entirely. Easier than adding arch-specific siginfo
structs to the codebase.
Bug: google-breakpad:791
Change-Id: Ia473e3ffa61fce4c42cf4c1e73a9df044599bc5c
Reviewed-on: https://chromium-review.googlesource.com/c/breakpad/breakpad/+/1524447
Reviewed-by: Mark Mentovai <mark@chromium.org>
Many signals in Linux support additional metadata on a per-signal
basis. We can extract that from NT_SIGINFO and pass it through
in the exception_information fields.
The current core dumper logic doesn't set exception_information
at all, so this is an improvement.
Bug: google-breakpad:791
Change-Id: I38b78d6494e9bc682441750d98ac9be5b0656f5a
Reviewed-on: https://chromium-review.googlesource.com/c/breakpad/breakpad/+/1497662
Reviewed-by: Mark Mentovai <mark@chromium.org>
The current failure message omits the underlying errno. This can
make diagnosing failures a bit difficult unless you run everything
through strace. For example:
$ core2md core /proc/self md
$ core2md core /proc/self md
Unable to generate minidump
Now we get the errno details:
Unable to generate minidump: File exists
Change-Id: I67f30879868ce4a726d5d888ee8c0a4a316b5186
Reviewed-on: https://chromium-review.googlesource.com/c/breakpad/breakpad/+/1497660
Reviewed-by: Ted Mielczarek <ted.mielczarek@gmail.com>
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>
Certain minidumps for 32-bit crashes have the upper 32-bit of the crash
address (which is a 64-bit value) set to non-zero values. This caused a
crash address with more than 32-bits to be printed out for minidumps of
32-bit architectures. This patch masks out those bits when reading the
raw minidump data to ensure this doesn't happen anymore.
Bug: google-breakpad:783
Change-Id: Ieef6dff759fd0ee2efc47c4c4a3cf863a48f0659
Reviewed-on: https://chromium-review.googlesource.com/c/1427819
Reviewed-by: Ted Mielczarek <ted.mielczarek@gmail.com>
This affects the output of tools like minidump_stackwalk which currently
print out the hexadecimal representation of the architecture instead of
the "arm64" string.
BUG=780
Change-Id: Id1d9d65fa5f3509c8c6580e2e3042f7d682b52be
Reviewed-on: https://chromium-review.googlesource.com/c/1412004
Reviewed-by: Mike Frysinger <vapier@chromium.org>
Eventually, I want to remove the current version of
SetFirstChanceHandler. That is why I changed the name of the current
callback type to FirstChanceHandlerDeprecated.
I also made sure that it is not possible to have two different
FirstChanceHandlers set at the same time.
This is the first of a set of CLs to clean up the API between Chrome,
BreakPad, and V8. See more information in the tracking bug.
R=mark@chromium.org
Bug: chromium:921971
Change-Id: Ia8c2fd9bd875c36dd7ae8bb4a02e538556bc67a1
Reviewed-on: https://chromium-review.googlesource.com/c/1411776
Reviewed-by: Mark Mentovai <mark@chromium.org>
The high_pc is an address and has already been read from .debug_addr
before being passed into FuncHandler::ProcessAttributeUnsigned.
Bug:870908
Change-Id: I950098e360b5193f26bf767b8fa0a5f9d59e66ce
Reviewed-on: https://chromium-review.googlesource.com/1178760
Reviewed-by: Mark Mentovai <mark@chromium.org>
This enables the DWARF reader to properly parse DW_AT_ranges attributes
in compilation units and functions. Code covered by a function is now
represented by a vector of ranges instead of a single contiguous range
and DW_AT_ranges entries are used to populate it. All the code and tests
that assumed functions to be contiguous entities has been updated to
reflect the change. DW_AT_ranges attributes found in compilation units
are parsed but no data is generated for them as it is not currently needed.
BUG=754
Change-Id: I310391b525aaba0dd329f1e3187486f2e0c6d442
Reviewed-on: https://chromium-review.googlesource.com/1124721
Reviewed-by: Ted Mielczarek <ted.mielczarek@gmail.com>
This struct matches the layout defined by Microsoft and replaces
Breakpad's MDRawContextARM64_Old. This CL updates the processor to
understand either the old or new structs, but clients continue to write
the old structs.
Change-Id: I8dedd9ddb2ec083b802723b9ac87beb18d98edbd
Reviewed-on: https://chromium-review.googlesource.com/1155938
Reviewed-by: Mark Mentovai <mark@chromium.org>
dump_syms produces incomplete CFI info on iOS because it doesn't support
converting compact unwind to Breakpad symbols. Attempting to use
incomplete CFI can result in infinte stack traces.
Bug: google-breakpad:764
Change-Id: Id042aa515d17928cb5503a79038607d95c56238d
Reviewed-on: https://chromium-review.googlesource.com/1128252
Reviewed-by: Ivan Penkov <ivanpe@chromium.org>
When DW_AT_MIPS_linkage_name doesn't demangle, breakpad currently throws
the symbol completely, but in some cases, there is no DW_AT_name or
DW_AT_abstract_origin to figure out a name, and the raw value from
DW_AT_MIPS_linkage_name is still better than nothing. Fall back to that
in when there is nothing else.
R=ted@mielczarek.org
Change-Id: I5cc7580244f2b99f5f1f279d09b904031cae1a37
Reviewed-on: https://chromium-review.googlesource.com/1082176
Reviewed-by: Ted Mielczarek <ted.mielczarek@gmail.com>
The variables in the CL are not initialized. Even if it's safe not to
initialize them here, MSAN doesn't know that.
Bug: 394028
Change-Id: I597a7d76aa19d5789decd0f85150fa31c9655269
Reviewed-on: https://chromium-review.googlesource.com/1001573
Reviewed-by: Lei Zhang <thestig@chromium.org>
