If the language for a DWARF type is not found or unrecognized, we should
fall back to the global default, not the program default (the program
default language is for language-specific operations on the program, so
DWARF parsing shouldn't depend on it). Add a fall_back parameter to
drgn_language_from_die() and use it in DWARF parsing, and replace
drgn_language_or_default() with a drgn_default_language variable.
Signed-off-by: Omar Sandoval <osandov@osandov.com>
We should only increment a held object's reference count when it is
initially inserted into the set; subsequent holds are no-ops.
Fixes: a8d632b4c1 ("libdrgn/python: use F14 instead of PyDict for Program::objects")
Signed-off-by: Omar Sandoval <osandov@osandov.com>
realloc(ptr, 0) is equivalent to free(ptr). It may return NULL, in which
case vector_do_shrink_to_fit() won't update the vector's data and
capacity. A subsequent append will then try to reuse the previous
allocation, causing a use-after-free. free() empty vectors explicitly
instead.
Fixes: 8d52536271 ("libdrgn: add common vector implementation")
Signed-off-by: Omar Sandoval <osandov@osandov.com>
Right now, an empty builder vector will not have anything to free, but
if we start pre-reserving these later, it will be a leak.
Fixes: c7af566c6e ("libdrgn: deduplicate all types with no members/parameters/enumerators")
Signed-off-by: Omar Sandoval <osandov@osandov.com>
Even if a compound, function, or enumerated type is complete, we can
still deduplicate it as long as it doesn't have members, parameters, or
enumerators.
Signed-off-by: Omar Sandoval <osandov@osandov.com>
Without this, the only way to check whether an object is absent in
Python is to try to use the object and catch the ObjectAbsentError.
Signed-off-by: Omar Sandoval <osandov@osandov.com>
I was going to add an Object.available_ attribute, but that made me
realize that the naming is somewhat ambiguous, as a reference object
with an invalid address might also be considered "unavailable" by users.
Use the name "absent" instead, which is more clear: the object isn't
there at all.
Signed-off-by: Omar Sandoval <osandov@osandov.com>
Make TypeMember.bit_field_size consistent with Object.bit_field_size_ by
using None to represent a non-bit field instead of 0.
Signed-off-by: Omar Sandoval <osandov@osandov.com>
The == operator on drgn.Type is only intended for testing. It's
expensive and slow and not what people usually want. It's going to get
even more awkward to define once types can refer to objects (for
template parameters and static members and such). Let's replace == with
a new identical() function only available in unit tests. Then, remove
the operator from the Python bindings as well as the underlying libdrgn
drgn_type_eq() and drgn_qualified_type_eq() functions.
Signed-off-by: Omar Sandoval <osandov@osandov.com>
Currently, we try to emulate the GNU C extension of casting a struct
type to itself. This does a deep type comparison, which is expensive. We
could take a shortcut like only comparing the kind and type name, but
seeing as standard C only allows casting to a scalar type, let's drop
support for casting to a struct (or other non-scalar) type entirely.
Signed-off-by: Omar Sandoval <osandov@osandov.com>
offsetof() can almost be implemented with Type.member(name).offset, but
that doesn't parse member designators. Add an offsetof() function that
does (and add drgn_type_offsetof() in libdrgn).
Signed-off-by: Omar Sandoval <osandov@osandov.com>
Add drgn_type_has_member() to libdrgn and Type.has_member() to the
Python bindings. This can simplify some version checks, like the one in
_for_each_block_device() since commit 9a10a927b0 ("helpers: fix
for_each_{disk,partition}() on kernels >= v5.1").
Signed-off-by: Omar Sandoval <osandov@osandov.com>
In Python, looking up a member in a drgn Type by name currently looks
something like:
member = [member for member in type.members if member.name == "foo"][0]
Add a Type.member(name) method, which is both easier and more efficient.
Signed-off-by: Omar Sandoval <osandov@osandov.com>
Now that types are associated with their program, we don't need to pass
the program separately to drgn_program_member_info() and can replace it
with a more natural drgn_type_find_member() API that takes only the type
and member name. While we're at it, get rid of drgn_member_info and
return the drgn_type_member and bit_offset directly. This also fixes a
bug that drgn_error_member_not_found() ignores the member name length.
Signed-off-by: Omar Sandoval <osandov@osandov.com>
The TypeMember and TypeParameter instances referring to a libdrgn
drgn_lazy_type are only valid as long as the Type containing them is
still alive. Hold a reference on the containing Type from LazyType. We
can do this without growing LazyType by getting rid of the enum state
and using sentinel values for LazyType::lazy_type as the state.
Signed-off-by: Omar Sandoval <osandov@osandov.com>
We can get struct drgn_object down from 40 bytes to 32 bytes (on x86-64)
by moving the bit_offset and little_endian members out of the value and
reference structs.
Signed-off-by: Omar Sandoval <osandov@osandov.com>
There are a couple of reasons that it was the wrong choice to have a
bit_offset for value objects:
1. When we store a buffer with a bit_offset, we're storing useless
padding bits.
2. bit_offset describes a location, or in other words, part of an
address. This makes sense for references, but not for values, which
are just a bag of bytes.
Get rid of union drgn_value.bit_offset in libdrgn, make
Object.bit_offset None for value objects, and disallow passing
bit_offset to the Object() constructor when creating a value. bit_offset
can still be passed when creating an object from a buffer, but we'll
shift the bytes down as necessary to store the value with no offset.
Signed-off-by: Omar Sandoval <osandov@osandov.com>
THREAD_SIZE is still broken and I haven't looked into the root cause
(see commit 95be142d17 ("tests: disable THREAD_SIZE test")). We don't
need it anymore anyways, so let's remove it entirely.
Signed-off-by: Omar Sandoval <osandov@osandov.com>
On old kernels, we set the initial frame as containing only rbp and let
libdwfl unwind it assuming frame pointers from there. This means that
the initial frame has a garbage rip. Follow the frame pointer and set
the previous rbp and return address ourselves instead.
Signed-off-by: Omar Sandoval <osandov@osandov.com>
There are some situations where we can find an object but can't
determine its value, like local variables that have been optimized out,
inlined functions without a concrete instance, and pure virtual methods.
It's still useful to get some information from these objects, namely
their types. Let's add the concept of an "unavailable" object, which is
an object with a known type but unknown value/address.
Signed-off-by: Omar Sandoval <osandov@osandov.com>
I'd like to use the name drgn_object_kind to distinguish between values
and references. "Encoding" is more accurate than "kind", anyways.
Signed-off-by: Omar Sandoval <osandov@osandov.com>
There are several places where we'd like to enforce that every
enumeration is handled in a switch. Add SWITCH_ENUM() and
SWITCH_ENUM_DEFAULT() macros for that and use them.
Signed-off-by: Omar Sandoval <osandov@osandov.com>
If virtual address translation isn't implemented for the target
architecture, then we shouldn't add the page table memory reader. If we
do, we get a DRGN_ERROR_INVALID_ARGUMENT error from
linux_helper_read_vm() instead of a DRGN_ERROR_FAULT error as expected.
Signed-off-by: Omar Sandoval <osandov@osandov.com>
If the DWARF index encounters any error while parsing, it returns an
error saying only "debug information is truncated", which makes it hard
to track down parsing errors. The kmod index parser silently swallows
errors. For both, replace the mread functions with a higher-level
binary_buffer interface that can include more information including the
location of the error. For example:
/tmp/mybinary: .debug_info+0x4: expected at least 56 bytes, have 55
Signed-off-by: Omar Sandoval <osandov@osandov.com>
Back in commit 9ce9094ee0 ("libdrgn: dwarf_index: don't copy sections
into each CU"), I changed the sections to be individual members. The
next change will be easier if they're in an array.
Signed-off-by: Omar Sandoval <osandov@osandov.com>
There are several places where we manually pass around the string name
of a tag so it can be used for error messages. Do it programatically
instead.
Signed-off-by: Omar Sandoval <osandov@osandov.com>
Linux v5.8 changed the module section structure, so we need to get the
section name differently.
Closes#73.
Reported-by: Serapheim Dimitropoulos <serapheim@delphix.com>
Signed-off-by: Omar Sandoval <osandov@osandov.com>
If cache_kernel_module_sections() in report_loaded_kernel_module()
fails, we continue to the next iteration without advancing to the next
kernel module. Then, we fail on that same kernel module and repeat. Make
sure that we go to the next kernel module.
Fixes: 423d2cd500 ("libdrgn: dwarf_index: rework file reporting")
Reported-by: Serapheim Dimitropoulos <serapheim@delphix.com>
Signed-off-by: Omar Sandoval <osandov@osandov.com>
We're freeing path and then using it to report an error.
This has some weird knock-on effects. Since we freed the path, the error
message contains garbage. So, PyErr_SetString() can't decode it as a
UTF-8 string. The end result is a MissingDebugInfoError with no message.
Fix it by creating the error before freeing the path.
Signed-off-by: Omar Sandoval <osandov@osandov.com>
We use /proc/modules and /sys/module to find loaded kernel modules for
the running kernel instead of walking the module list in the core dump
as an optimization. To make it easier to test the core dump path, add an
environment variable to disable the optimization.
Signed-off-by: Omar Sandoval <osandov@osandov.com>
The next commit will allow using the offline path for the live kernel,
so the offline naming won't make much sense. Fold the offline path into
the top-level functions, and make the live path an escape hatch. Also
add some comments and improve naming for the file and directory handles
and update the coding style.
Signed-off-by: Omar Sandoval <osandov@osandov.com>
These were added in commit e5874ad18a ("libdrgn: use libdwfl"), but
they have never been used. Remove them.
Signed-off-by: Omar Sandoval <osandov@osandov.com>
Use *_hash_pair() for hash functions that do the full double hashing and
return a struct hash_pair and hash_*() for other hashing utility
functions. Also change some of the equality function names to be more
symmetric and improve the documentation.
Signed-off-by: Omar Sandoval <osandov@osandov.com>
min() and max() from the Linux kernel go through the trouble of
resulting in a constant expression if the arguments are constant
expressions, but they can't be used outside of a function due to their
use of ({ }). This means that they can't be used for, e.g., enumerators
or global arrays. Let's simplify min() and max() and instead add
explicit min_iconst() and max_iconst() macros that can be used
everywhere that an integer constant expression is required. We can then
use it in hash_table.h. While we're here, let's split these into their
own header file and document them better.
Signed-off-by: Omar Sandoval <osandov@osandov.com>
drgn_type_members_eq() skips comparing the types of anonymous members.
Fix that and add a test for it.
Signed-off-by: Omar Sandoval <osandov@osandov.com>
The Doxygen documentation for libdrgn has bit-rotted over time. Bring
back the Internal module, clean up a few renamed members and parameters,
and fix broken parsing caused by the generic definition macros.
Signed-off-by: Omar Sandoval <osandov@osandov.com>
I recently hit a couple of CI failures caused by relying on transitive
includes that weren't always present. include-what-you-use is a
Clang-based tool that helps with this. It's a bit finicky and noisy, so
this adds scripts/iwyu.py to make running it more convenient (but not
reliable enough to automate it in Travis).
This cleans up all reasonable include-what-you-use warnings and
reorganizes a few header files.
Signed-off-by: Omar Sandoval <osandov@osandov.com>
The elfutils header files should be treated as if they were in the
standard location, so use -isystem instead of -I.
Signed-off-by: Omar Sandoval <osandov@osandov.com>
