zircon/system/ulib/inspector/memory.cc

// Copyright 2019 The Fuchsia Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include <algorithm>
#include <assert.h>
#include <stdint.h>
#include <stdio.h>

#include <pretty/hexdump.h>
#include <zircon/syscalls.h>

#include "inspector/inspector.h"
#include "utils-impl.h"

// How much memory we can dump at a time, in bytes.
// Space for this is allocated on the stack, so this can't be too large.
static constexpr size_t kMemoryDumpChunkSize = 256;
// The hexdump routines print 16 bytes at a time.
static constexpr size_t kHexdumpLineBytes = 16;
static_assert(kMemoryDumpChunkSize % kHexdumpLineBytes == 0, "");

__EXPORT void inspector_print_memory(FILE* f, zx_handle_t process, zx_vaddr_t start,
                                     size_t length) {
  uint8_t buf[kMemoryDumpChunkSize];
  size_t bytes_read;

  zx_vaddr_t addr = start;
  for (size_t i = 0; i < length; i += kMemoryDumpChunkSize, addr += kMemoryDumpChunkSize) {
    size_t to_read = std::min(sizeof(buf), length - i);
    zx_status_t status = zx_process_read_memory(process, addr, buf, to_read, &bytes_read);
    if (status < 0) {
      fprintf(f, "inspector: failed reading memory @0x%lx, error: %d\n", addr, status);
      break;
    }
    if (bytes_read == 0) {
      fprintf(f, "inspector: zero bytes read @0x%lx\n", addr);
      break;
    }

    hexdump_very_ex(buf, bytes_read, addr, hexdump_stdio_printf, f);

    // If we got a short read we're done, no point in continuing.
    if (bytes_read < kMemoryDumpChunkSize)
      break;
  }
}