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https://github.com/JakeHillion/drgn.git
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c0bc72b0ea
The current array-based memory reader has a bug in the following
scenario:
prog.add_memory_segment(0xffff0000, 128, ...)
# This should replace a subset of the first segment.
prog.add_memory_segment(0xffff0020, 32, ...)
# This moves the first segment back to the front of the array.
prog.read(0xffff0000, 32)
# This finds the first segment instead of the second segment.
prog.read(0xffff0032, 32)
Fix it by using the newly-added splay tree. This also splits up the
virtual and physical memory segments into separate trees.
133 lines
3.5 KiB
C
133 lines
3.5 KiB
C
// Copyright 2018-2019 - Omar Sandoval
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// SPDX-License-Identifier: GPL-3.0+
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/**
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* @file
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*
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* Memory reading interface.
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*
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* See @ref MemoryReader.
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*/
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#ifndef DRGN_MEMORY_READER_H
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#define DRGN_MEMORY_READER_H
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#include <stdbool.h>
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#include <stddef.h>
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#include <stdint.h>
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#include "binary_search_tree.h"
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/**
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* @ingroup Internals
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*
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* @defgroup MemoryReader Memory reader
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*
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* Memory reading interface.
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*
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* @ref drgn_memory_reader provides a common interface for registering regions
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* of memory in a program and reading from memory.
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*
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* @{
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*/
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/** Memory segment in a @ref drgn_memory_reader. */
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struct drgn_memory_segment {
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struct binary_tree_node node;
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/** Address of the segment in memory. */
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uint64_t address;
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/** Size of the segment in bytes; */
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uint64_t size;
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/**
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* The address of the segment when it was added, before any truncations.
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*
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* This is always greater than or equal to @ref
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* drgn_memory_segment::address.
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*/
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uint64_t orig_address;
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/** Read callback. */
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drgn_memory_read_fn read_fn;
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/** Argument to pass to @ref drgn_memory_segment::read_fn. */
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void *arg;
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};
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static inline uint64_t
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drgn_memory_segment_to_key(const struct drgn_memory_segment *entry)
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{
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return entry->address;
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}
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DEFINE_BINARY_SEARCH_TREE_TYPE(drgn_memory_segment_tree, struct
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drgn_memory_segment, node,
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drgn_memory_segment_to_key)
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/**
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* Memory reader.
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*
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* A memory reader maps the segments of memory in an address space to callbacks
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* which can be used to read memory from those segments.
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*/
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struct drgn_memory_reader {
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/** Virtual memory segments. */
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struct drgn_memory_segment_tree virtual_segments;
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/** Physical memory segments. */
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struct drgn_memory_segment_tree physical_segments;
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};
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/**
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* Initialize a @ref drgn_memory_reader.
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*
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* The reader is initialized with no segments.
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*/
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void drgn_memory_reader_init(struct drgn_memory_reader *reader);
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/** Deinitialize a @ref drgn_memory_reader. */
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void drgn_memory_reader_deinit(struct drgn_memory_reader *reader);
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/** Return whether a @ref drgn_memory_reader has no segments. */
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bool drgn_memory_reader_empty(struct drgn_memory_reader *reader);
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/** @sa drgn_program_add_memory_segment() */
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struct drgn_error *
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drgn_memory_reader_add_segment(struct drgn_memory_reader *reader,
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uint64_t address, uint64_t size,
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drgn_memory_read_fn read_fn, void *arg,
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bool physical);
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/**
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* Read from a @ref drgn_memory_reader.
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*
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* @param[in] reader Memory reader.
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* @param[out] buf Buffer to read into.
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* @param[in] address Starting address in memory to read.
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* @param[in] count Number of bytes to read.
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* @param[in] physical Whether @c address is physical.
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* @return @c NULL on success, non-@c NULL on error.
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*/
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struct drgn_error *drgn_memory_reader_read(struct drgn_memory_reader *reader,
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void *buf, uint64_t address,
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size_t count, bool physical);
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/** Argument for @ref drgn_read_memory_file(). */
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struct drgn_memory_file_segment {
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/** Offset in the file where the segment starts. */
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uint64_t file_offset;
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/**
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* Size of the segment in the file. This may be less than the size of
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* the segment in memory, in which case the remaining bytes are treated
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* as if they contained zeroes.
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*/
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uint64_t file_size;
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/** File descriptor. */
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int fd;
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};
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/** @ref drgn_memory_read_fn which reads from a file. */
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struct drgn_error *drgn_read_memory_file(void *buf, uint64_t address,
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size_t count, uint64_t offset,
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void *arg, bool physical);
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/** @} */
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#endif /* DRGN_MEMORY_READER_H */
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