Commit Graph

63 Commits

Author SHA1 Message Date
Omar Sandoval
c0d8709b45 Update copyright headers to Meta
Signed-off-by: Omar Sandoval <osandov@osandov.com>
2021-11-21 15:59:44 -08:00
Omar Sandoval
7335df114c libdrgn: python: add Object.to_bytes_()
And the libdrgn implementation, drgn_object_read_bytes().

Signed-off-by: Omar Sandoval <osandov@osandov.com>
2021-07-26 17:12:34 -07:00
Omar Sandoval
9c00552007 libdrgn: python: add Object.from_bytes_()
Add a way to create an object from raw bytes. One example where I've
wanted this is creating a struct pt_regs from a PRSTATUS note or other
source.

Signed-off-by: Omar Sandoval <osandov@osandov.com>
2021-07-26 17:06:58 -07:00
Omar Sandoval
a4b9d68a8c Use GPL-3.0-or-later license identifier instead of GPL-3.0+
Apparently the latter is deprecated and the former is preferred.

Signed-off-by: Omar Sandoval <osandov@osandov.com>
2021-04-03 01:10:35 -07:00
Omar Sandoval
ca1a2598fd libdrgn: python: add missing function name to Object.format_() exceptions
The ":function name" is missing from the PyArg_ParseTupleAndKeywords()
call in DrgnObject_format(), so errors say, for example, "'foo' is an
invalid keyword argument for this function" instead of "for format_()".

Fixes: cf3a07bdfb ("libdrgn: python: replace Object.__format__ with Object.format_")
Signed-off-by: Omar Sandoval <osandov@osandov.com>
2021-03-08 14:27:33 -08:00
Omar Sandoval
b5ed892481 Fix some include-what-you-use warnings and update for Bear 3
Bear 3 changed the CLI arguments, so update scripts/iwyu.py for it and
clean up some new warnings.

Signed-off-by: Omar Sandoval <osandov@osandov.com>
2021-02-26 16:05:49 -08:00
Omar Sandoval
55e3a58e06 libdrgn: python: use correct member offset when creating object from value
We need to use the offset of the member in the outermost object type,
not the offset in the immediate containing type in the case of nested
anonymous structs.

Fixes: e72ecd0e2c ("libdrgn: replace drgn_program_member_info() with drgn_type_find_member()")
Signed-off-by: Omar Sandoval <osandov@osandov.com>
2021-02-21 02:29:59 -08:00
Omar Sandoval
9fda010789 Track byte order in scalar types instead of objects
Currently, reference objects and buffer value objects have a byte order.
However, this doesn't always make sense for a couple of reasons:

- Byte order is only meaningful for scalars. What does it mean for a
  struct to be big endian? A struct doesn't have a most or least
  significant byte; its scalar members do.
- The DWARF specification allows either types or variables to have a
  byte order (DW_AT_endianity). The only producer I could find that uses
  this is GCC for the scalar_storage_order type attribute, and it only
  uses it for base types, not variables. GDB only seems to use to check
  it for base types, as well.

So, remove the byte order from objects, and move it to integer, boolean,
floating-point, and pointer types. This model makes more sense, and it
means that we can get the binary representation of any object now.

The only downside is that we can no longer support a bit offset for
non-scalars, but as far as I can tell, nothing needs that.

Signed-off-by: Omar Sandoval <osandov@osandov.com>
2021-02-19 21:41:29 -08:00
Omar Sandoval
72b4aa9669 libdrgn: clean up object initialization
Rename struct drgn_object_type to struct drgn_operand_type, add a new
struct drgn_object_type which contains all of the type-related fields
from struct drgn_object, and use it to implement drgn_object_type() and
drgn_object_type_operand(), which are replacements for
drgn_object_set_common() and drgn_object_type_encoding_and_size(). This
cleans up a lot of the boilerplate around initializing objects.

Signed-off-by: Omar Sandoval <osandov@osandov.com>
2021-02-19 17:43:14 -08:00
Omar Sandoval
78316a28fb libdrgn: remove half-baked support for complex types
We've nominally supported complex types since commit 75c3679147
("Rewrite drgn core in C"), but parsing them from DWARF has been
incorrect from the start (they don't have a DW_AT_type attribute like we
assume), and we never implemented proper support for complex objects.
Drop the partial implementation; we can bring it back (properly) if
someone requests it.

Signed-off-by: Omar Sandoval <osandov@osandov.com>
2021-02-17 14:56:33 -08:00
Omar Sandoval
0d35dec8ee libdrgn: python: define Py_RETURN_BOOL
And use it instead of an if statement with
Py_RETURN_TRUE/Py_RETURN_FALSE or PyBool_FromLong().

Signed-off-by: Omar Sandoval <osandov@osandov.com>
2021-01-28 11:35:09 -08:00
Omar Sandoval
d35243b354 libdrgn: replace lazy types with lazy objects
In order to support static members, methods, default function arguments,
and value template parameters, we need to be able to store a drgn_object
in a drgn_type_member or drgn_type_parameter. These are all cases where
we want lazy evaluation, so we can replace drgn_lazy_type with a new
drgn_lazy_object which implements the same idea but for objects. Types
can still be represented with an absent object.

Signed-off-by: Omar Sandoval <osandov@osandov.com>
2021-01-08 17:39:51 -08:00
Omar Sandoval
190062f470 libdrgn: get drgn_type_member.bit_field_size through drgn_member_type()
Getting the bit field size of a member will soon require evaluating the
lazy type, so return it from drgn_member_type() instead of accessing it
directly.

Signed-off-by: Omar Sandoval <osandov@osandov.com>
2021-01-08 17:39:51 -08:00
Omar Sandoval
988e9e7190 libdrgn/python: add Object.absent_
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>
2020-12-29 15:06:40 -08:00
Omar Sandoval
30cfa40a72 libdrgn: rename "unavailable" objects to "absent" objects
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>
2020-12-29 14:58:26 -08:00
Omar Sandoval
e72ecd0e2c libdrgn: replace drgn_program_member_info() with drgn_type_find_member()
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>
2020-12-15 14:40:54 -08:00
Omar Sandoval
738ae2c75f libdrgn: pack struct drgn_object better
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>
2020-12-14 12:29:17 -08:00
Omar Sandoval
abafdd965f Remove bit_offset from value objects
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>
2020-12-14 12:29:17 -08:00
Omar Sandoval
6bd0c2b4d2 libdrgn: add concept of "unavailable" objects
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>
2020-12-04 13:58:19 -08:00
Omar Sandoval
5f17281926 libdrgn: make drgn_object::is_reference an enum
To prepare for a new kind of object, replace the is_reference bool with
an enum drgn_object_kind.

Signed-off-by: Omar Sandoval <osandov@osandov.com>
2020-12-04 13:37:58 -08:00
Omar Sandoval
edb1fe7f2f libdrgn: rename drgn_object_kind to drgn_object_encoding
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>
2020-12-04 12:02:26 -08:00
Omar Sandoval
286c09844e Clean up #includes with include-what-you-use
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>
2020-09-23 16:29:42 -07:00
Omar Sandoval
e49a87a3d7 libdrgn: remove struct drgn_object::prog
We can get it via the type now.

Signed-off-by: Omar Sandoval <osandov@osandov.com>
2020-08-27 11:31:21 -07:00
Omar Sandoval
a97f6c4fa2 Associate types with program
I originally envisioned types as dumb descriptors. This mostly works for
C because in C, types are fairly simple. However, even then the
drgn_program_member_info() API is awkward. You should be able to look up
a member directly from a type, but we need the program for caching
purposes. This has also held me back from adding offsetof() or
has_member() APIs.

Things get even messier with C++. C++ template parameters can be objects
(e.g., template <int N>). Such parameters would best be represented by a
drgn object, which we need a drgn program for. Static members are a
similar case.

So, let's reimagine types as being owned by a program. This has a few
parts:

1. In libdrgn, simple types are now created by factory functions,
   drgn_foo_type_create().
2. To handle their variable length fields, compound types, enum types,
   and function types are constructed with a "builder" API.
3. Simple types are deduplicated.
4. The Python type factory functions are replaced by methods of the
   Program class.
5. While we're changing the API, the parameters to pointer_type() and
   array_type() are reordered to be more logical (and to allow
   pointer_type() to take a default size of None for the program's
   default pointer size).
6. Likewise, the type factory methods take qualifiers as a keyword
   argument only.

A big part of this change is updating the tests and splitting up large
test cases into smaller ones in a few places.

Signed-off-by: Omar Sandoval <osandov@osandov.com>
2020-08-26 17:41:09 -07:00
Omar Sandoval
d4e0771f87 libdrgn: return error from drgn_program_{is_little_endian,bswap,is_64_bit}()
Most places that call these check has_platform and return an error, and
those that don't can live with the extra check.

Signed-off-by: Omar Sandoval <osandov@osandov.com>
2020-08-26 16:56:28 -07:00
Omar Sandoval
971a2d3687 libdrgn/python: make Objects fully immutable
The model has always been that drgn Objects are immutable, but for some
reason I went through the trouble of allowing __init__() to reinitialize
an already initialized Object. Instead, let's fully initialize the
Object in __new__() and get rid of __init__().
2020-05-18 00:07:49 -07:00
Omar Sandoval
ab876f3dbd libdrgn/python: allow specifying Object value positionally
It's annoying to have to do value= when creating objects, especially in
interactive mode. Let's allow passing in the value positionally so that
`Object(prog, "int", value=0)` becomes `Object(prog, "int", 0)`. It's
clear enough that this is creating an int with value 0.
2020-05-18 00:07:49 -07:00
Omar Sandoval
8b264f8823 Update copyright headers to Facebook and add missing headers
drgn was originally my side project, but for awhile now it's also been
my work project. Update the copyright headers to reflect this, and add a
copyright header to various files that were missing it.
2020-05-15 15:13:02 -07:00
Omar Sandoval
0a100064c1 libdrgn: improve and rename DRGN_UNREACHABLE()
DRGN_UNREACHABLE() currently expands to abort(), but assert() provides
more information. If NDEBUG is defined, we can use
__builtin_unreachable() instead.

DRGN_UNREACHABLE() isn't drgn-specific, so this renames it to
UNREACHABLE(). It's also not really related to errors, so this moves it
to internal.h.
2020-05-07 15:16:22 -07:00
Omar Sandoval
ea3cdb43f7 libdrgn/python: optimize Object.__getattribute__()
DrgnObject_getattro() uses PyObject_GenericGetAttr() and catches the
AttributeError raised if the name is not an attribute of the Object
class. If the member is found, we then destroy the AttributeError.
Raising an exception only to destroy it is obviously wasteful. Luckily,
as of Python 3.7, the lower-level _PyObject_GenericGetAttrWithDict() can
suppress the AttributeError; we can raise it ourselves if we need it. In
my microbenchmarks, this makes Object.__getattribute__() at least twice
as fast when the member exists.

This also fixes a drgn_error leak.
2020-04-20 17:45:30 -07:00
Omar Sandoval
79f973007b libdrgn/python: fix reference counting on Object.type_
We need to keep the Program alive for its types to stay valid, not just
the objects the Program has pinned. (I have no idea why I changed this
in commit 565e0343ef ("libdrgn: make symbol index pluggable with
callbacks").)
2020-03-13 16:05:43 -07:00
Omar Sandoval
9de2cc8410 libdrgn/python: make Object.__index__() TypeError message clearer
Currently, we print:

>>> prog.symbol(prog['init_task'])
Traceback (most recent call last):
  File "<console>", line 1, in <module>
TypeError: cannot convert 'struct task_struct' to index

It's not obvious what it means to convert to an index. Instead, let's
use the error message raised by operator.index():

TypeError: 'struct task_struct' object cannot be interpreted as an integer
2020-02-11 09:19:53 -08:00
Serapheim Dimitropoulos
ad82e9623a Introduce OutOfBoundsError
Decouple some of the responsibilities of FaultError to
OutOfBoundsError so consumers can differentiate between
invalid memory accesses and running out of bounds in
drgn Objects which may be based on valid memory address.
2020-02-04 14:59:31 -08:00
Omar Sandoval
1443d17fb4 libdrgn: add DRGN_FORMAT_OBJECT_IMPLICIT_ELEMENTS 2019-12-19 11:43:54 -08:00
Omar Sandoval
db66952b2e libdrgn: add DRGN_FORMAT_OBJECT_IMPLICIT_MEMBERS 2019-12-19 11:43:54 -08:00
Omar Sandoval
c8434e9a9e libdrgn: add DRGN_FORMAT_OBJECT_ELEMENT_INDICES 2019-12-19 11:43:54 -08:00
Omar Sandoval
cfceb491db libdrgn: add DRGN_FORMAT_OBJECT_MEMBER_NAMES 2019-12-19 11:43:54 -08:00
Omar Sandoval
4fad941ec1 libdrgn: add DRGN_FORMAT_OBJECT_{MEMBERS,ELEMENTS}_SAME_LINE 2019-12-19 11:43:54 -08:00
Omar Sandoval
d77b7bd7e3 libdrgn: add DRGN_FORMAT_OBJECT_{TYPE_NAME,MEMBER_TYPE_NAMES,ELEMENT_TYPE_NAMES} 2019-12-19 11:43:54 -08:00
Omar Sandoval
89307c532a libdrgn: add DRGN_FORMAT_OBJECT_CHAR 2019-12-19 11:43:54 -08:00
Omar Sandoval
7cee597fff libdrgn: add DRGN_FORMAT_OBJECT_STRING 2019-12-19 11:43:54 -08:00
Omar Sandoval
5865fa4d16 libdrgn: add DRGN_FORMAT_OBJECT_SYMBOLIZE 2019-12-19 11:43:54 -08:00
Omar Sandoval
f58bc4bf3a libdrgn: add DRGN_FORMAT_OBJECT_DEREFERENCE 2019-12-19 11:43:54 -08:00
Omar Sandoval
5fb02f03fd libdrgn: add flags to drgn_format_object() 2019-12-19 11:43:54 -08:00
Omar Sandoval
cf3a07bdfb libdrgn: python: replace Object.__format__ with Object.format_
We'd like to have more control over how objects are formatted. I
considered defining a custom string format specification syntax, but
that's not easily discoverable. Instead, let's get rid of the current
format specification support and replace it with a normal method.
2019-12-19 11:43:52 -08:00
Omar Sandoval
3b22bd3022 libdrgn: rename pretty_print -> format
In preparation for making drgn_pretty_print_object() more flexible
(i.e., not always "pretty"), rename it to drgn_format_object(). For
consistency, let's rename drgn_pretty_print_type_name(),
drgn_pretty_print_type(), and drgn_pretty_print_stack_trace(), too.
2019-12-16 11:21:12 -08:00
Omar Sandoval
7b518fc2fd libdrgn: support negative array subscripts
This was an oversight, as negative indices are completely valid (and
occasionally useful, like when looking at a stack).
2019-11-29 21:06:37 -08:00
Omar Sandoval
2561226918 libdrgn: python: add signed integer support to index_converter
This is preparation for the next change.
2019-11-29 20:40:40 -08:00
Omar Sandoval
b8b93ae3e6 libdrgn: python: fix deprecation warning in unit tests
Some tests (e.g., tests.test_object.TestSpecialMethods.test_round) are
printing:

  DeprecationWarning: an integer is required (got type float).  Implicit
  conversion to integers using __int__ is deprecated, and may be removed
  in a future version of Python.

See https://bugs.python.org/issue36048. This is coming from calls like:

  Object(prog, 'int', value=1.5)

We actually want the truncating behavior, so explicitly call
PyNumber_Long().
2019-11-22 17:18:55 -08:00
Amlan Nayak
0df2152307 Add basic class type support
This implements the first step at supporting C++: class types. In
particular, this adds a new drgn_type_kind, DRGN_TYPE_CLASS, and support
for parsing DW_TAG_class_type from DWARF. Although classes are not valid
in C, this adds support for pretty printing them, for completeness.
2019-11-18 10:36:40 -08:00