1 files changed, 0 insertions, 283 deletions
diff --git a/simpleperf/kallsyms.cpp b/simpleperf/kallsyms.cpp
deleted file mode 100644
index f9a93589..00000000
--- a/simpleperf/kallsyms.cpp
+++ /dev/null
@@ -1,283 +0,0 @@
-/*
- * Copyright (C) 2020 The Android Open Source Project
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *      http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-#include "kallsyms.h"
-
-#include <inttypes.h>
-
-#include <string>
-
-#include <android-base/file.h>
-#include <android-base/logging.h>
-#include <android-base/properties.h>
-
-#include "environment.h"
-#include "utils.h"
-
-namespace simpleperf {
-
-#if defined(__linux__)
-
-namespace {
-
-const char kKallsymsPath[] = "/proc/kallsyms";
-const char kProcModulesPath[] = "/proc/modules";
-const char kPtrRestrictPath[] = "/proc/sys/kernel/kptr_restrict";
-const char kLowerPtrRestrictAndroidProp[] = "security.lower_kptr_restrict";
-const unsigned int kMinLineTestNonNullSymbols = 10;
-
-// Tries to read the kernel symbol file and ensure that at least some symbol
-// addresses are non-null.
-bool CanReadKernelSymbolAddresses() {
-  LineReader reader(kKallsymsPath);
-  if (!reader.Ok()) {
-    LOG(DEBUG) << "Failed to read " << kKallsymsPath;
-    return false;
-  }
-  auto symbol_callback = [&](const KernelSymbol& symbol) { return (symbol.addr != 0u); };
-  for (unsigned int i = 0; i < kMinLineTestNonNullSymbols; i++) {
-    std::string* line = reader.ReadLine();
-    if (line == nullptr) {
-      return false;
-    }
-    if (ProcessKernelSymbols(*line, symbol_callback)) {
-      return true;
-    }
-  }
-  return false;
-}
-
-// Define a scope in which access to kallsyms is possible.
-// This is based on the Perfetto implementation.
-class ScopedKptrUnrestrict {
- public:
-  ScopedKptrUnrestrict();   // Lowers kptr_restrict if necessary.
-  ~ScopedKptrUnrestrict();  // Restores the initial kptr_restrict.
-
-  // Indicates if access to kallsyms should be successful.
-  bool KallsymsAvailable() { return kallsyms_available_; }
-
-  static void ResetWarning() { kernel_address_warning_printed_ = false; }
-
- private:
-  bool WriteKptrRestrict(const std::string& value);
-  void PrintWarning();
-
-  bool restore_property_ = false;
-  bool restore_restrict_value_ = false;
-  std::string saved_restrict_value_;
-  bool kallsyms_available_ = false;
-
-  static bool kernel_address_warning_printed_;
-};
-
-bool ScopedKptrUnrestrict::kernel_address_warning_printed_ = false;
-
-ScopedKptrUnrestrict::ScopedKptrUnrestrict() {
-  if (CanReadKernelSymbolAddresses()) {
-    // Everything seems to work (e.g., we are running as root and kptr_restrict
-    // is < 2). Don't touching anything.
-    kallsyms_available_ = true;
-    return;
-  }
-
-  if (GetAndroidVersion() >= 12 && IsRoot()) {
-    // Enable kernel addresses by setting property.
-    if (!android::base::SetProperty(kLowerPtrRestrictAndroidProp, "1")) {
-      LOG(DEBUG) << "Unable to set " << kLowerPtrRestrictAndroidProp << " to 1.";
-      PrintWarning();
-      return;
-    }
-    restore_property_ = true;
-    // Init takes some time to react to the property change.
-    // Unfortunately, we cannot read kptr_restrict because of SELinux. Instead,
-    // we detect this by reading the initial lines of kallsyms and checking
-    // that they are non-zero. This loop waits for at most 250ms (50 * 5ms).
-    for (int attempt = 1; attempt <= 50; ++attempt) {
-      usleep(5000);
-      if (CanReadKernelSymbolAddresses()) {
-        kallsyms_available_ = true;
-        return;
-      }
-    }
-    LOG(DEBUG) << "kallsyms addresses are still masked after setting "
-               << kLowerPtrRestrictAndroidProp;
-    PrintWarning();
-    return;
-  }
-
-  // Otherwise, read the kptr_restrict value and lower it if needed.
-  if (!android::base::ReadFileToString(kPtrRestrictPath, &saved_restrict_value_)) {
-    LOG(DEBUG) << "Failed to read " << kPtrRestrictPath;
-    PrintWarning();
-    return;
-  }
-
-  // Progressively lower kptr_restrict until we can read kallsyms.
-  for (int value = atoi(saved_restrict_value_.c_str()); value > 0; --value) {
-    if (!WriteKptrRestrict(std::to_string(value))) {
-      break;
-    }
-    restore_restrict_value_ = true;
-    if (CanReadKernelSymbolAddresses()) {
-      kallsyms_available_ = true;
-      return;
-    }
-  }
-  PrintWarning();
-}
-
-ScopedKptrUnrestrict::~ScopedKptrUnrestrict() {
-  if (restore_property_) {
-    android::base::SetProperty(kLowerPtrRestrictAndroidProp, "0");
-  }
-  if (restore_restrict_value_) {
-    WriteKptrRestrict(saved_restrict_value_);
-  }
-}
-
-bool ScopedKptrUnrestrict::WriteKptrRestrict(const std::string& value) {
-  if (!android::base::WriteStringToFile(value, kPtrRestrictPath)) {
-    LOG(DEBUG) << "Failed to set " << kPtrRestrictPath << " to " << value;
-    return false;
-  }
-  return true;
-}
-
-void ScopedKptrUnrestrict::PrintWarning() {
-  if (!kernel_address_warning_printed_) {
-    kernel_address_warning_printed_ = true;
-    LOG(WARNING) << "Access to kernel symbol addresses is restricted. If "
-                 << "possible, please do `echo 0 >/proc/sys/kernel/kptr_restrict` "
-                 << "to fix this.";
-  }
-}
-
-}  // namespace
-
-std::vector<KernelMmap> GetLoadedModules() {
-  ScopedKptrUnrestrict kptr_unrestrict;
-  if (!kptr_unrestrict.KallsymsAvailable()) return {};
-  std::vector<KernelMmap> result;
-  LineReader reader(kProcModulesPath);
-  if (!reader.Ok()) {
-    // There is no /proc/modules on Android devices, so we don't print error if failed to open it.
-    PLOG(DEBUG) << "failed to open file /proc/modules";
-    return result;
-  }
-  std::string* line;
-  std::string name_buf;
-  while ((line = reader.ReadLine()) != nullptr) {
-    // Parse line like: nf_defrag_ipv6 34768 1 nf_conntrack_ipv6, Live 0xffffffffa0fe5000
-    name_buf.resize(line->size());
-    char* name = name_buf.data();
-    uint64_t addr;
-    uint64_t len;
-    if (sscanf(line->data(), "%s%" PRIu64 "%*u%*s%*s 0x%" PRIx64, name, &len, &addr) == 3) {
-      KernelMmap map;
-      map.name = name;
-      map.start_addr = addr;
-      map.len = len;
-      result.push_back(map);
-    }
-  }
-  bool all_zero = true;
-  for (const auto& map : result) {
-    if (map.start_addr != 0) {
-      all_zero = false;
-    }
-  }
-  if (all_zero) {
-    LOG(DEBUG) << "addresses in /proc/modules are all zero, so ignore kernel modules";
-    return std::vector<KernelMmap>();
-  }
-  return result;
-}
-
-uint64_t GetKernelStartAddress() {
-  ScopedKptrUnrestrict kptr_unrestrict;
-  if (!kptr_unrestrict.KallsymsAvailable()) return 0;
-  LineReader reader(kKallsymsPath);
-  if (!reader.Ok()) {
-    return 0;
-  }
-  std::string* line;
-  while ((line = reader.ReadLine()) != nullptr) {
-    if (strstr(line->data(), "_stext") != nullptr) {
-      uint64_t addr;
-      if (sscanf(line->data(), "%" PRIx64, &addr) == 1) {
-        return addr;
-      }
-    }
-  }
-  return 0;
-}
-
-bool LoadKernelSymbols(std::string* kallsyms) {
-  ScopedKptrUnrestrict kptr_unrestrict;
-  if (kptr_unrestrict.KallsymsAvailable()) {
-    return android::base::ReadFileToString(kKallsymsPath, kallsyms);
-  }
-  return false;
-}
-
-void ResetKernelAddressWarning() {
-  ScopedKptrUnrestrict::ResetWarning();
-}
-
-#endif  // defined(__linux__)
-
-bool ProcessKernelSymbols(std::string& symbol_data,
-                          const std::function<bool(const KernelSymbol&)>& callback) {
-  char* p = &symbol_data[0];
-  char* data_end = p + symbol_data.size();
-  while (p < data_end) {
-    char* line_end = strchr(p, '\n');
-    if (line_end != nullptr) {
-      *line_end = '\0';
-    }
-    size_t line_size = (line_end != nullptr) ? (line_end - p) : (data_end - p);
-    // Parse line like: ffffffffa005c4e4 d __warned.41698       [libsas]
-    char name[line_size];
-    char module[line_size];
-    strcpy(module, "");
-
-    KernelSymbol symbol;
-    int ret = sscanf(p, "%" PRIx64 " %c %s%s", &symbol.addr, &symbol.type, name, module);
-    if (line_end != nullptr) {
-      *line_end = '\n';
-      p = line_end + 1;
-    } else {
-      p = data_end;
-    }
-    if (ret >= 3) {
-      symbol.name = name;
-      size_t module_len = strlen(module);
-      if (module_len > 2 && module[0] == '[' && module[module_len - 1] == ']') {
-        module[module_len - 1] = '\0';
-        symbol.module = &module[1];
-      } else {
-        symbol.module = nullptr;
-      }
-
-      if (callback(symbol)) {
-        return true;
-      }
-    }
-  }
-  return false;
-}
-
-}  // namespace simpleperf