simpleperf/environment.cpp - platform/system/extras - Git at Google

 /*
  * Copyright (C) 2015 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 "environment.h"

 #include <inttypes.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <unordered_map>
 #include <vector>

 #include <base/file.h>
 #include <base/logging.h>
 #include <base/strings.h>
 #include <base/stringprintf.h>

 #include "read_elf.h"
 #include "utils.h"

 std::vector<int> GetOnlineCpus() {
   std::vector<int> result;
   FILE* fp = fopen("/sys/devices/system/cpu/online", "re");
   if (fp == nullptr) {
     PLOG(ERROR) << "can't open online cpu information";
     return result;
   }

   LineReader reader(fp);
   char* line;
   if ((line = reader.ReadLine()) != nullptr) {
     result = GetOnlineCpusFromString(line);
   }
   CHECK(!result.empty()) << "can't get online cpu information";
   return result;
 }

 std::vector<int> GetOnlineCpusFromString(const std::string& s) {
   std::vector<int> result;
   bool have_dash = false;
   const char* p = s.c_str();
   char* endp;
   long cpu;
   // Parse line like: 0,1-3, 5, 7-8
   while ((cpu = strtol(p, &endp, 10)) != 0 || endp != p) {
     if (have_dash && result.size() > 0) {
       for (int t = result.back() + 1; t < cpu; ++t) {
         result.push_back(t);
       }
     }
     have_dash = false;
     result.push_back(cpu);
     p = endp;
     while (!isdigit(*p) && *p != '\0') {
       if (*p == '-') {
         have_dash = true;
       }
       ++p;
     }
   }
   return result;
 }

 bool ProcessKernelSymbols(const std::string& symbol_file,
                           std::function<bool(const KernelSymbol&)> callback) {
   FILE* fp = fopen(symbol_file.c_str(), "re");
   if (fp == nullptr) {
     PLOG(ERROR) << "failed to open file " << symbol_file;
     return false;
   }
   LineReader reader(fp);
   char* line;
   while ((line = reader.ReadLine()) != nullptr) {
     // Parse line like: ffffffffa005c4e4 d __warned.41698       [libsas]
     char name[reader.MaxLineSize()];
     char module[reader.MaxLineSize()];
     strcpy(module, "");

     KernelSymbol symbol;
     if (sscanf(line, "%" PRIx64 " %c %s%s", &symbol.addr, &symbol.type, name, module) < 3) {
       continue;
     }
     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;
 }

 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;
   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.
     PLOG(DEBUG) << "failed to open file /proc/modules";
     return result;
   }
   LineReader reader(fp);
   char* line;
   while ((line = reader.ReadLine()) != nullptr) {
     // Parse line like: nf_defrag_ipv6 34768 1 nf_conntrack_ipv6, Live 0xffffffffa0fe5000
     char name[reader.MaxLineSize()];
     uint64_t addr;
     if (sscanf(line, "%s%*lu%*u%*s%*s 0x%" PRIx64, name, &addr) == 2) {
       ModuleMmap map;
       map.name = name;
       map.start_addr = addr;
       result.push_back(map);
     }
   }
   return result;
 }

 static std::string GetLinuxVersion() {
   std::string content;
   if (android::base::ReadFileToString("/proc/version", &content)) {
     char s[content.size() + 1];
     if (sscanf(content.c_str(), "Linux version %s", s) == 1) {
       return s;
     }
   }
   PLOG(FATAL) << "can't read linux version";
   return "";
 }

 static void GetAllModuleFiles(const std::string& path,
                               std::unordered_map<std::string, std::string>* module_file_map) {
   std::vector<std::string> files;
   std::vector<std::string> subdirs;
   GetEntriesInDir(path, &files, &subdirs);
   for (auto& name : files) {
     if (android::base::EndsWith(name, ".ko")) {
       std::string module_name = name.substr(0, name.size() - 3);
       std::replace(module_name.begin(), module_name.end(), '-', '_');
       module_file_map->insert(std::make_pair(module_name, path + name));
     }
   }
   for (auto& name : subdirs) {
     GetAllModuleFiles(path + "/" + name, module_file_map);
   }
 }

 static std::vector<ModuleMmap> GetModulesInUse() {
   // TODO: There is no /proc/modules or /lib/modules on Android, find methods work on it.
   std::vector<ModuleMmap> 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;
   GetAllModuleFiles(module_dirpath, &module_file_map);
   for (auto& module : module_mmaps) {
     auto it = module_file_map.find(module.name);
     if (it != module_file_map.end()) {
       module.filepath = it->second;
     }
   }
   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;
   }
   kernel_mmap->name = DEFAULT_KERNEL_MMAP_NAME;
   *module_mmaps = GetModulesInUse();
   if (module_mmaps->size() == 0) {
     kernel_mmap->len = ULLONG_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);
     // 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;
     } else {
       kernel_mmap->len = (*module_mmaps)[0].start_addr - kernel_mmap->start_addr - 1;
     }
     for (size_t i = 0; i + 1 < module_mmaps->size(); ++i) {
       if ((*module_mmaps)[i].start_addr == (*module_mmaps)[i + 1].start_addr) {
         (*module_mmaps)[i].len = 0;
       } else {
         (*module_mmaps)[i].len =
             (*module_mmaps)[i + 1].start_addr - (*module_mmaps)[i].start_addr - 1;
       }
     }
     module_mmaps->back().len = ULLONG_MAX - module_mmaps->back().start_addr;
   }
   return true;
 }

 static bool StringToPid(const std::string& s, pid_t* pid) {
   char* endptr;
   *pid = static_cast<pid_t>(strtol(s.c_str(), &endptr, 10));
   return *endptr == '\0';
 }

 static bool ReadThreadNameAndTgid(const std::string& status_file, std::string* comm, pid_t* tgid) {
   FILE* fp = fopen(status_file.c_str(), "re");
   if (fp == nullptr) {
     return false;
   }
   bool read_comm = false;
   bool read_tgid = false;
   LineReader reader(fp);
   char* line;
   while ((line = reader.ReadLine()) != nullptr) {
     char s[reader.MaxLineSize()];
     if (sscanf(line, "Name:%s", s) == 1) {
       *comm = s;
       read_comm = true;
     } else if (sscanf(line, "Tgid:%d", tgid) == 1) {
       read_tgid = true;
     }
     if (read_comm && read_tgid) {
       return true;
     }
   }
   return false;
 }

 static bool GetThreadComm(pid_t pid, std::vector<ThreadComm>* thread_comms) {
   std::string task_dirname = android::base::StringPrintf("/proc/%d/task", pid);
   std::vector<std::string> subdirs;
   GetEntriesInDir(task_dirname, nullptr, &subdirs);
   for (auto& name : subdirs) {
     pid_t tid;
     if (!StringToPid(name, &tid)) {
       continue;
     }
     std::string status_file = task_dirname + "/" + name + "/status";
     std::string comm;
     pid_t tgid;
     if (!ReadThreadNameAndTgid(status_file, &comm, &tgid)) {
       return false;
     }
     ThreadComm thread;
     thread.tid = tid;
     thread.tgid = tgid;
     thread.comm = comm;
     thread.is_process = (tid == pid);
     thread_comms->push_back(thread);
   }
   return true;
 }

 bool GetThreadComms(std::vector<ThreadComm>* thread_comms) {
   thread_comms->clear();
   std::vector<std::string> subdirs;
   GetEntriesInDir("/proc", nullptr, &subdirs);
   for (auto& name : subdirs) {
     pid_t pid;
     if (!StringToPid(name, &pid)) {
       continue;
     }
     if (!GetThreadComm(pid, thread_comms)) {
       return false;
     }
   }
   return true;
 }

 bool GetThreadMmapsInProcess(pid_t pid, std::vector<ThreadMmap>* thread_mmaps) {
   std::string map_file = android::base::StringPrintf("/proc/%d/maps", pid);
   FILE* fp = fopen(map_file.c_str(), "re");
   if (fp == nullptr) {
     PLOG(DEBUG) << "can't open file " << map_file;
     return false;
   }
   thread_mmaps->clear();
   LineReader reader(fp);
   char* line;
   while ((line = reader.ReadLine()) != nullptr) {
     // Parse line like: 00400000-00409000 r-xp 00000000 fc:00 426998  /usr/lib/gvfs/gvfsd-http
     uint64_t start_addr, end_addr, pgoff;
     char type[reader.MaxLineSize()];
     char execname[reader.MaxLineSize()];
     strcpy(execname, "");
     if (sscanf(line, "%" PRIx64 "-%" PRIx64 " %s %" PRIx64 " %*x:%*x %*u %s\n", &start_addr,
                &end_addr, type, &pgoff, execname) < 4) {
       continue;
     }
     if (strcmp(execname, "") == 0) {
       strcpy(execname, DEFAULT_EXECNAME_FOR_THREAD_MMAP);
     }
     ThreadMmap thread;
     thread.start_addr = start_addr;
     thread.len = end_addr - start_addr;
     thread.pgoff = pgoff;
     thread.name = execname;
     thread.executable = (type[2] == 'x');
     thread_mmaps->push_back(thread);
   }
   return true;
 }

 bool GetKernelBuildId(BuildId* build_id) {
   return GetBuildIdFromNoteFile("/sys/kernel/notes", build_id);
 }

 bool GetModuleBuildId(const std::string& module_name, BuildId* build_id) {
   std::string notefile = "/sys/module/" + module_name + "/notes/.note.gnu.build-id";
   return GetBuildIdFromNoteFile(notefile, build_id);
 }
	/*
	* Copyright (C) 2015 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 "environment.h"

	#include <inttypes.h>
	#include <stdio.h>
	#include <stdlib.h>
	#include <unordered_map>
	#include <vector>

	#include <base/file.h>
	#include <base/logging.h>
	#include <base/strings.h>
	#include <base/stringprintf.h>

	#include "read_elf.h"
	#include "utils.h"

	std::vector<int> GetOnlineCpus() {
	std::vector<int> result;
	FILE* fp = fopen("/sys/devices/system/cpu/online", "re");
	if (fp == nullptr) {
	PLOG(ERROR) << "can't open online cpu information";
	return result;
	}

	LineReader reader(fp);
	char* line;
	if ((line = reader.ReadLine()) != nullptr) {
	result = GetOnlineCpusFromString(line);
	}
	CHECK(!result.empty()) << "can't get online cpu information";
	return result;
	}

	std::vector<int> GetOnlineCpusFromString(const std::string& s) {
	std::vector<int> result;
	bool have_dash = false;
	const char* p = s.c_str();
	char* endp;
	long cpu;
	// Parse line like: 0,1-3, 5, 7-8
	while ((cpu = strtol(p, &endp, 10)) != 0 \|\| endp != p) {
	if (have_dash && result.size() > 0) {
	for (int t = result.back() + 1; t < cpu; ++t) {
	result.push_back(t);
	}
	}
	have_dash = false;
	result.push_back(cpu);
	p = endp;
	while (!isdigit(p) && p != '\0') {
	if (*p == '-') {
	have_dash = true;
	}
	++p;
	}
	}
	return result;
	}

	bool ProcessKernelSymbols(const std::string& symbol_file,
	std::function<bool(const KernelSymbol&)> callback) {
	FILE* fp = fopen(symbol_file.c_str(), "re");
	if (fp == nullptr) {
	PLOG(ERROR) << "failed to open file " << symbol_file;
	return false;
	}
	LineReader reader(fp);
	char* line;
	while ((line = reader.ReadLine()) != nullptr) {
	// Parse line like: ffffffffa005c4e4 d __warned.41698 [libsas]
	char name[reader.MaxLineSize()];
	char module[reader.MaxLineSize()];
	strcpy(module, "");

	KernelSymbol symbol;
	if (sscanf(line, "%" PRIx64 " %c %s%s", &symbol.addr, &symbol.type, name, module) < 3) {
	continue;
	}
	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;
	}

	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;
	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.
	PLOG(DEBUG) << "failed to open file /proc/modules";
	return result;
	}
	LineReader reader(fp);
	char* line;
	while ((line = reader.ReadLine()) != nullptr) {
	// Parse line like: nf_defrag_ipv6 34768 1 nf_conntrack_ipv6, Live 0xffffffffa0fe5000
	char name[reader.MaxLineSize()];
	uint64_t addr;
	if (sscanf(line, "%s%lu%u%s%s 0x%" PRIx64, name, &addr) == 2) {
	ModuleMmap map;
	map.name = name;
	map.start_addr = addr;
	result.push_back(map);
	}
	}
	return result;
	}

	static std::string GetLinuxVersion() {
	std::string content;
	if (android::base::ReadFileToString("/proc/version", &content)) {
	char s[content.size() + 1];
	if (sscanf(content.c_str(), "Linux version %s", s) == 1) {
	return s;
	}
	}
	PLOG(FATAL) << "can't read linux version";
	return "";
	}

	static void GetAllModuleFiles(const std::string& path,
	std::unordered_map<std::string, std::string>* module_file_map) {
	std::vector<std::string> files;
	std::vector<std::string> subdirs;
	GetEntriesInDir(path, &files, &subdirs);
	for (auto& name : files) {
	if (android::base::EndsWith(name, ".ko")) {
	std::string module_name = name.substr(0, name.size() - 3);
	std::replace(module_name.begin(), module_name.end(), '-', '_');
	module_file_map->insert(std::make_pair(module_name, path + name));
	}
	}
	for (auto& name : subdirs) {
	GetAllModuleFiles(path + "/" + name, module_file_map);
	}
	}

	static std::vector<ModuleMmap> GetModulesInUse() {
	// TODO: There is no /proc/modules or /lib/modules on Android, find methods work on it.
	std::vector<ModuleMmap> 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;
	GetAllModuleFiles(module_dirpath, &module_file_map);
	for (auto& module : module_mmaps) {
	auto it = module_file_map.find(module.name);
	if (it != module_file_map.end()) {
	module.filepath = it->second;
	}
	}
	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;
	}
	kernel_mmap->name = DEFAULT_KERNEL_MMAP_NAME;
	*module_mmaps = GetModulesInUse();
	if (module_mmaps->size() == 0) {
	kernel_mmap->len = ULLONG_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);
	// 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;
	} else {
	kernel_mmap->len = (*module_mmaps)[0].start_addr - kernel_mmap->start_addr - 1;
	}
	for (size_t i = 0; i + 1 < module_mmaps->size(); ++i) {
	if ((module_mmaps)[i].start_addr == (module_mmaps)[i + 1].start_addr) {
	(*module_mmaps)[i].len = 0;
	} else {
	(*module_mmaps)[i].len =
	(module_mmaps)[i + 1].start_addr - (module_mmaps)[i].start_addr - 1;
	}
	}
	module_mmaps->back().len = ULLONG_MAX - module_mmaps->back().start_addr;
	}
	return true;
	}

	static bool StringToPid(const std::string& s, pid_t* pid) {
	char* endptr;
	*pid = static_cast<pid_t>(strtol(s.c_str(), &endptr, 10));
	return *endptr == '\0';
	}

	static bool ReadThreadNameAndTgid(const std::string& status_file, std::string* comm, pid_t* tgid) {
	FILE* fp = fopen(status_file.c_str(), "re");
	if (fp == nullptr) {
	return false;
	}
	bool read_comm = false;
	bool read_tgid = false;
	LineReader reader(fp);
	char* line;
	while ((line = reader.ReadLine()) != nullptr) {
	char s[reader.MaxLineSize()];
	if (sscanf(line, "Name:%s", s) == 1) {
	*comm = s;
	read_comm = true;
	} else if (sscanf(line, "Tgid:%d", tgid) == 1) {
	read_tgid = true;
	}
	if (read_comm && read_tgid) {
	return true;
	}
	}
	return false;
	}

	static bool GetThreadComm(pid_t pid, std::vector<ThreadComm>* thread_comms) {
	std::string task_dirname = android::base::StringPrintf("/proc/%d/task", pid);
	std::vector<std::string> subdirs;
	GetEntriesInDir(task_dirname, nullptr, &subdirs);
	for (auto& name : subdirs) {
	pid_t tid;
	if (!StringToPid(name, &tid)) {
	continue;
	}
	std::string status_file = task_dirname + "/" + name + "/status";
	std::string comm;
	pid_t tgid;
	if (!ReadThreadNameAndTgid(status_file, &comm, &tgid)) {
	return false;
	}
	ThreadComm thread;
	thread.tid = tid;
	thread.tgid = tgid;
	thread.comm = comm;
	thread.is_process = (tid == pid);
	thread_comms->push_back(thread);
	}
	return true;
	}

	bool GetThreadComms(std::vector<ThreadComm>* thread_comms) {
	thread_comms->clear();
	std::vector<std::string> subdirs;
	GetEntriesInDir("/proc", nullptr, &subdirs);
	for (auto& name : subdirs) {
	pid_t pid;
	if (!StringToPid(name, &pid)) {
	continue;
	}
	if (!GetThreadComm(pid, thread_comms)) {
	return false;
	}
	}
	return true;
	}

	bool GetThreadMmapsInProcess(pid_t pid, std::vector<ThreadMmap>* thread_mmaps) {
	std::string map_file = android::base::StringPrintf("/proc/%d/maps", pid);
	FILE* fp = fopen(map_file.c_str(), "re");
	if (fp == nullptr) {
	PLOG(DEBUG) << "can't open file " << map_file;
	return false;
	}
	thread_mmaps->clear();
	LineReader reader(fp);
	char* line;
	while ((line = reader.ReadLine()) != nullptr) {
	// Parse line like: 00400000-00409000 r-xp 00000000 fc:00 426998 /usr/lib/gvfs/gvfsd-http
	uint64_t start_addr, end_addr, pgoff;
	char type[reader.MaxLineSize()];
	char execname[reader.MaxLineSize()];
	strcpy(execname, "");
	if (sscanf(line, "%" PRIx64 "-%" PRIx64 " %s %" PRIx64 " %x:%x %*u %s\n", &start_addr,
	&end_addr, type, &pgoff, execname) < 4) {
	continue;
	}
	if (strcmp(execname, "") == 0) {
	strcpy(execname, DEFAULT_EXECNAME_FOR_THREAD_MMAP);
	}
	ThreadMmap thread;
	thread.start_addr = start_addr;
	thread.len = end_addr - start_addr;
	thread.pgoff = pgoff;
	thread.name = execname;
	thread.executable = (type[2] == 'x');
	thread_mmaps->push_back(thread);
	}
	return true;
	}

	bool GetKernelBuildId(BuildId* build_id) {
	return GetBuildIdFromNoteFile("/sys/kernel/notes", build_id);
	}

	bool GetModuleBuildId(const std::string& module_name, BuildId* build_id) {
	std::string notefile = "/sys/module/" + module_name + "/notes/.note.gnu.build-id";
	return GetBuildIdFromNoteFile(notefile, build_id);
	}