#include <android-base/strings.h>
#include <android-base/stringprintf.h>
+#if defined(__ANDROID__)
+#include <sys/system_properties.h>
+#endif
+
#include "read_elf.h"
#include "utils.h"
return false;
}
-static bool FindStartOfKernelSymbolCallback(const KernelSymbol& symbol, uint64_t* start_addr) {
- if (symbol.module == nullptr) {
- *start_addr = symbol.addr;
- return true;
- }
- return false;
-}
-
-static bool FindStartOfKernelSymbol(const std::string& symbol_file, uint64_t* start_addr) {
- return ProcessKernelSymbols(
- symbol_file, std::bind(&FindStartOfKernelSymbolCallback, std::placeholders::_1, start_addr));
-}
-
-static bool FindKernelFunctionSymbolCallback(const KernelSymbol& symbol, const std::string& name,
- uint64_t* addr) {
- if ((symbol.type == 'T' || symbol.type == 'W' || symbol.type == 'A') &&
- symbol.module == nullptr && name == symbol.name) {
- *addr = symbol.addr;
- return true;
- }
- return false;
-}
-
-static bool FindKernelFunctionSymbol(const std::string& symbol_file, const std::string& name,
- uint64_t* addr) {
- return ProcessKernelSymbols(
- symbol_file, std::bind(&FindKernelFunctionSymbolCallback, std::placeholders::_1, name, addr));
-}
-
-std::vector<ModuleMmap> GetLoadedModules() {
- std::vector<ModuleMmap> result;
+static std::vector<KernelMmap> GetLoadedModules() {
+ std::vector<KernelMmap> result;
FILE* fp = fopen("/proc/modules", "re");
if (fp == nullptr) {
// There is no /proc/modules on Android devices, so we don't print error if failed to open it.
char name[reader.MaxLineSize()];
uint64_t addr;
if (sscanf(line, "%s%*lu%*u%*s%*s 0x%" PRIx64, name, &addr) == 2) {
- ModuleMmap map;
+ KernelMmap map;
map.name = name;
map.start_addr = addr;
result.push_back(map);
}
}
-static std::vector<ModuleMmap> GetModulesInUse() {
+static std::vector<KernelMmap> GetModulesInUse() {
// TODO: There is no /proc/modules or /lib/modules on Android, find methods work on it.
- std::vector<ModuleMmap> module_mmaps = GetLoadedModules();
+ std::vector<KernelMmap> module_mmaps = GetLoadedModules();
std::string linux_version = GetLinuxVersion();
std::string module_dirpath = "/lib/modules/" + linux_version + "/kernel";
std::unordered_map<std::string, std::string> module_file_map;
return module_mmaps;
}
-bool GetKernelAndModuleMmaps(KernelMmap* kernel_mmap, std::vector<ModuleMmap>* module_mmaps) {
- if (!FindStartOfKernelSymbol("/proc/kallsyms", &kernel_mmap->start_addr)) {
- LOG(DEBUG) << "call FindStartOfKernelSymbol() failed";
- return false;
- }
- if (!FindKernelFunctionSymbol("/proc/kallsyms", "_text", &kernel_mmap->pgoff)) {
- LOG(DEBUG) << "call FindKernelFunctionSymbol() failed";
- return false;
- }
+void GetKernelAndModuleMmaps(KernelMmap* kernel_mmap, std::vector<KernelMmap>* module_mmaps) {
kernel_mmap->name = DEFAULT_KERNEL_MMAP_NAME;
+ kernel_mmap->start_addr = 0;
+ kernel_mmap->filepath = kernel_mmap->name;
*module_mmaps = GetModulesInUse();
+ for (auto& map : *module_mmaps) {
+ if (map.filepath.empty()) {
+ map.filepath = "[" + map.name + "]";
+ }
+ }
+
if (module_mmaps->size() == 0) {
kernel_mmap->len = std::numeric_limits<unsigned long long>::max() - kernel_mmap->start_addr;
} else {
std::sort(
module_mmaps->begin(), module_mmaps->end(),
- [](const ModuleMmap& m1, const ModuleMmap& m2) { return m1.start_addr < m2.start_addr; });
- CHECK_LE(kernel_mmap->start_addr, (*module_mmaps)[0].start_addr);
+ [](const KernelMmap& m1, const KernelMmap& m2) { return m1.start_addr < m2.start_addr; });
// When not having enough privilege, all addresses are read as 0.
if (kernel_mmap->start_addr == (*module_mmaps)[0].start_addr) {
kernel_mmap->len = 0;
module_mmaps->back().len =
std::numeric_limits<unsigned long long>::max() - module_mmaps->back().start_addr;
}
- return true;
}
static bool ReadThreadNameAndTgid(const std::string& status_file, std::string* comm, pid_t* tgid) {
*exec_path = path;
return true;
}
+
+/*
+ * perf event paranoia level:
+ * -1 - not paranoid at all
+ * 0 - disallow raw tracepoint access for unpriv
+ * 1 - disallow cpu events for unpriv
+ * 2 - disallow kernel profiling for unpriv
+ * 3 - disallow user profiling for unpriv
+ */
+static bool ReadPerfEventParanoid(int* value) {
+ std::string s;
+ if (!android::base::ReadFileToString("/proc/sys/kernel/perf_event_paranoid", &s)) {
+ PLOG(ERROR) << "failed to read /proc/sys/kernel/perf_event_paranoid";
+ return false;
+ }
+ s = android::base::Trim(s);
+ if (!android::base::ParseInt(s.c_str(), value)) {
+ PLOG(ERROR) << "failed to parse /proc/sys/kernel/perf_event_paranoid: " << s;
+ return false;
+ }
+ return true;
+}
+
+static const char* GetLimitLevelDescription(int limit_level) {
+ switch (limit_level) {
+ case -1: return "unlimited";
+ case 0: return "disallowing raw tracepoint access for unpriv";
+ case 1: return "disallowing cpu events for unpriv";
+ case 2: return "disallowing kernel profiling for unpriv";
+ case 3: return "disallowing user profiling for unpriv";
+ default: return "unknown level";
+ }
+}
+
+bool CheckPerfEventLimit() {
+ // root is not limited by /proc/sys/kernel/perf_event_paranoid.
+ if (IsRoot()) {
+ return true;
+ }
+ int limit_level;
+ if (!ReadPerfEventParanoid(&limit_level)) {
+ return false;
+ }
+ if (limit_level <= 1) {
+ return true;
+ }
+#if defined(__ANDROID__)
+ // Try to enable perf_event_paranoid by setprop security.perf_harden=0.
+ if (__system_property_set("security.perf_harden", "0") == 0) {
+ sleep(1);
+ if (ReadPerfEventParanoid(&limit_level) && limit_level <= 1) {
+ return true;
+ }
+ }
+ LOG(WARNING) << "/proc/sys/kernel/perf_event_paranoid is " << limit_level
+ << ", " << GetLimitLevelDescription(limit_level) << ".";
+ LOG(WARNING) << "Try using `adb shell setprop security.perf_harden 0` to allow profiling.";
+#else
+ LOG(WARNING) << "/proc/sys/kernel/perf_event_paranoid is " << limit_level
+ << ", " << GetLimitLevelDescription(limit_level) << ".";
+#endif
+ return true;
+}
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