diff options
Diffstat (limited to 'mozglue/baseprofiler/core/shared-libraries-linux.cc')
| -rw-r--r-- | mozglue/baseprofiler/core/shared-libraries-linux.cc | 855 |
1 files changed, 855 insertions, 0 deletions
diff --git a/mozglue/baseprofiler/core/shared-libraries-linux.cc b/mozglue/baseprofiler/core/shared-libraries-linux.cc new file mode 100644 index 0000000000..84680bb59b --- /dev/null +++ b/mozglue/baseprofiler/core/shared-libraries-linux.cc @@ -0,0 +1,855 @@ +/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */ +/* vim: set ts=8 sts=2 et sw=2 tw=80: */ +/* This Source Code Form is subject to the terms of the Mozilla Public + * License, v. 2.0. If a copy of the MPL was not distributed with this + * file, You can obtain one at http://mozilla.org/MPL/2.0/. */ + +#include "BaseProfilerSharedLibraries.h" + +#define PATH_MAX_TOSTRING(x) #x +#define PATH_MAX_STRING(x) PATH_MAX_TOSTRING(x) +#include <stdio.h> +#include <string.h> +#include <limits.h> +#include <unistd.h> +#include <fstream> +#include "platform.h" +#include "mozilla/Sprintf.h" + +#include <algorithm> +#include <arpa/inet.h> +#include <elf.h> +#include <fcntl.h> +#if defined(GP_OS_linux) || defined(GP_OS_android) +# include <features.h> +#endif +#include <sys/mman.h> +#include <sys/stat.h> +#include <sys/types.h> +#include <vector> + +#if defined(GP_OS_linux) || defined(GP_OS_android) || defined(GP_OS_freebsd) +# include <link.h> // dl_phdr_info, ElfW() +#else +# error "Unexpected configuration" +#endif + +#if defined(GP_OS_android) +extern "C" MOZ_EXPORT __attribute__((weak)) int dl_iterate_phdr( + int (*callback)(struct dl_phdr_info* info, size_t size, void* data), + void* data); +#endif + +#if defined(GP_OS_freebsd) && !defined(ElfW) +# define ElfW(type) Elf_##type +#endif + +// ---------------------------------------------------------------------------- +// Starting imports from toolkit/crashreporter/google-breakpad/, as needed by +// this file when moved to mozglue. + +// Imported from +// toolkit/crashreporter/google-breakpad/src/common/memory_range.h. +// A lightweight wrapper with a pointer and a length to encapsulate a contiguous +// range of memory. It provides helper methods for checked access of a subrange +// of the memory. Its implemementation does not allocate memory or call into +// libc functions, and is thus safer to use in a crashed environment. +class MemoryRange { + public: + MemoryRange() : data_(NULL), length_(0) {} + + MemoryRange(const void* data, size_t length) { Set(data, length); } + + // Returns true if this memory range contains no data. + bool IsEmpty() const { + // Set() guarantees that |length_| is zero if |data_| is NULL. + return length_ == 0; + } + + // Resets to an empty range. + void Reset() { + data_ = NULL; + length_ = 0; + } + + // Sets this memory range to point to |data| and its length to |length|. + void Set(const void* data, size_t length) { + data_ = reinterpret_cast<const uint8_t*>(data); + // Always set |length_| to zero if |data_| is NULL. + length_ = data ? length : 0; + } + + // Returns true if this range covers a subrange of |sub_length| bytes + // at |sub_offset| bytes of this memory range, or false otherwise. + bool Covers(size_t sub_offset, size_t sub_length) const { + // The following checks verify that: + // 1. sub_offset is within [ 0 .. length_ - 1 ] + // 2. sub_offset + sub_length is within + // [ sub_offset .. length_ ] + return sub_offset < length_ && sub_offset + sub_length >= sub_offset && + sub_offset + sub_length <= length_; + } + + // Returns a raw data pointer to a subrange of |sub_length| bytes at + // |sub_offset| bytes of this memory range, or NULL if the subrange + // is out of bounds. + const void* GetData(size_t sub_offset, size_t sub_length) const { + return Covers(sub_offset, sub_length) ? (data_ + sub_offset) : NULL; + } + + // Same as the two-argument version of GetData() but uses sizeof(DataType) + // as the subrange length and returns an |DataType| pointer for convenience. + template <typename DataType> + const DataType* GetData(size_t sub_offset) const { + return reinterpret_cast<const DataType*>( + GetData(sub_offset, sizeof(DataType))); + } + + // Returns a raw pointer to the |element_index|-th element of an array + // of elements of length |element_size| starting at |sub_offset| bytes + // of this memory range, or NULL if the element is out of bounds. + const void* GetArrayElement(size_t element_offset, size_t element_size, + unsigned element_index) const { + size_t sub_offset = element_offset + element_index * element_size; + return GetData(sub_offset, element_size); + } + + // Same as the three-argument version of GetArrayElement() but deduces + // the element size using sizeof(ElementType) and returns an |ElementType| + // pointer for convenience. + template <typename ElementType> + const ElementType* GetArrayElement(size_t element_offset, + unsigned element_index) const { + return reinterpret_cast<const ElementType*>( + GetArrayElement(element_offset, sizeof(ElementType), element_index)); + } + + // Returns a subrange of |sub_length| bytes at |sub_offset| bytes of + // this memory range, or an empty range if the subrange is out of bounds. + MemoryRange Subrange(size_t sub_offset, size_t sub_length) const { + return Covers(sub_offset, sub_length) + ? MemoryRange(data_ + sub_offset, sub_length) + : MemoryRange(); + } + + // Returns a pointer to the beginning of this memory range. + const uint8_t* data() const { return data_; } + + // Returns the length, in bytes, of this memory range. + size_t length() const { return length_; } + + private: + // Pointer to the beginning of this memory range. + const uint8_t* data_; + + // Length, in bytes, of this memory range. + size_t length_; +}; + +// Imported from +// toolkit/crashreporter/google-breakpad/src/common/linux/memory_mapped_file.h +// and inlined .cc. +// A utility class for mapping a file into memory for read-only access of the +// file content. Its implementation avoids calling into libc functions by +// directly making system calls for open, close, mmap, and munmap. +class MemoryMappedFile { + public: + MemoryMappedFile() {} + + // Constructor that calls Map() to map a file at |path| into memory. + // If Map() fails, the object behaves as if it is default constructed. + MemoryMappedFile(const char* path, size_t offset) { Map(path, offset); } + + MemoryMappedFile(const MemoryMappedFile&) = delete; + MemoryMappedFile& operator=(const MemoryMappedFile&) = delete; + + ~MemoryMappedFile() {} + + // Maps a file at |path| into memory, which can then be accessed via + // content() as a MemoryRange object or via data(), and returns true on + // success. Mapping an empty file will succeed but with data() and size() + // returning NULL and 0, respectively. An existing mapping is unmapped + // before a new mapping is created. + bool Map(const char* path, size_t offset) { + Unmap(); + + int fd = open(path, O_RDONLY, 0); + if (fd == -1) { + return false; + } + +#if defined(__x86_64__) || defined(__aarch64__) || \ + (defined(__mips__) && _MIPS_SIM == _ABI64) || \ + !(defined(GP_OS_linux) || defined(GP_OS_android)) + + struct stat st; + if (fstat(fd, &st) == -1 || st.st_size < 0) { +#else + struct stat64 st; + if (fstat64(fd, &st) == -1 || st.st_size < 0) { +#endif + close(fd); + return false; + } + + // Strangely file size can be negative, but we check above that it is not. + size_t file_len = static_cast<size_t>(st.st_size); + // If the file does not extend beyond the offset, simply use an empty + // MemoryRange and return true. Don't bother to call mmap() + // even though mmap() can handle an empty file on some platforms. + if (offset >= file_len) { + close(fd); + return true; + } + + void* data = mmap(NULL, file_len, PROT_READ, MAP_PRIVATE, fd, offset); + close(fd); + if (data == MAP_FAILED) { + return false; + } + + content_.Set(data, file_len - offset); + return true; + } + + // Unmaps the memory for the mapped file. It's a no-op if no file is + // mapped. + void Unmap() { + if (content_.data()) { + munmap(const_cast<uint8_t*>(content_.data()), content_.length()); + content_.Set(NULL, 0); + } + } + + // Returns a MemoryRange object that covers the memory for the mapped + // file. The MemoryRange object is empty if no file is mapped. + const MemoryRange& content() const { return content_; } + + // Returns a pointer to the beginning of the memory for the mapped file. + // or NULL if no file is mapped or the mapped file is empty. + const void* data() const { return content_.data(); } + + // Returns the size in bytes of the mapped file, or zero if no file + // is mapped. + size_t size() const { return content_.length(); } + + private: + // Mapped file content as a MemoryRange object. + MemoryRange content_; +}; + +// Imported from +// toolkit/crashreporter/google-breakpad/src/common/linux/file_id.h and inlined +// .cc. +// GNU binutils' ld defaults to 'sha1', which is 160 bits == 20 bytes, +// so this is enough to fit that, which most binaries will use. +// This is just a sensible default for vectors so most callers can get away with +// stack allocation. +static const size_t kDefaultBuildIdSize = 20; + +// Used in a few places for backwards-compatibility. +typedef struct { + uint32_t data1; + uint16_t data2; + uint16_t data3; + uint8_t data4[8]; +} MDGUID; /* GUID */ + +const size_t kMDGUIDSize = sizeof(MDGUID); + +class FileID { + public: + explicit FileID(const char* path) : path_(path) {} + ~FileID() {} + + // Load the identifier for the elf file path specified in the constructor into + // |identifier|. + // + // The current implementation will look for a .note.gnu.build-id + // section and use that as the file id, otherwise it falls back to + // XORing the first 4096 bytes of the .text section to generate an identifier. + bool ElfFileIdentifier(std::vector<uint8_t>& identifier) { + MemoryMappedFile mapped_file(path_.c_str(), 0); + if (!mapped_file.data()) // Should probably check if size >= ElfW(Ehdr)? + return false; + + return ElfFileIdentifierFromMappedFile(mapped_file.data(), identifier); + } + + // Traits classes so consumers can write templatized code to deal + // with specific ELF bits. + struct ElfClass32 { + typedef Elf32_Addr Addr; + typedef Elf32_Ehdr Ehdr; + typedef Elf32_Nhdr Nhdr; + typedef Elf32_Phdr Phdr; + typedef Elf32_Shdr Shdr; + typedef Elf32_Half Half; + typedef Elf32_Off Off; + typedef Elf32_Sym Sym; + typedef Elf32_Word Word; + + static const int kClass = ELFCLASS32; + static const uint16_t kMachine = EM_386; + static const size_t kAddrSize = sizeof(Elf32_Addr); + static constexpr const char* kMachineName = "x86"; + }; + + struct ElfClass64 { + typedef Elf64_Addr Addr; + typedef Elf64_Ehdr Ehdr; + typedef Elf64_Nhdr Nhdr; + typedef Elf64_Phdr Phdr; + typedef Elf64_Shdr Shdr; + typedef Elf64_Half Half; + typedef Elf64_Off Off; + typedef Elf64_Sym Sym; + typedef Elf64_Word Word; + + static const int kClass = ELFCLASS64; + static const uint16_t kMachine = EM_X86_64; + static const size_t kAddrSize = sizeof(Elf64_Addr); + static constexpr const char* kMachineName = "x86_64"; + }; + + // Internal helper method, exposed for convenience for callers + // that already have more info. + template <typename ElfClass> + static const typename ElfClass::Shdr* FindElfSectionByName( + const char* name, typename ElfClass::Word section_type, + const typename ElfClass::Shdr* sections, const char* section_names, + const char* names_end, int nsection) { + if (!name || !sections || nsection == 0) { + return NULL; + } + + int name_len = strlen(name); + if (name_len == 0) return NULL; + + for (int i = 0; i < nsection; ++i) { + const char* section_name = section_names + sections[i].sh_name; + if (sections[i].sh_type == section_type && + names_end - section_name >= name_len + 1 && + strcmp(name, section_name) == 0) { + return sections + i; + } + } + return NULL; + } + + struct ElfSegment { + const void* start; + size_t size; + }; + + // Convert an offset from an Elf header into a pointer to the mapped + // address in the current process. Takes an extra template parameter + // to specify the return type to avoid having to dynamic_cast the + // result. + template <typename ElfClass, typename T> + static const T* GetOffset(const typename ElfClass::Ehdr* elf_header, + typename ElfClass::Off offset) { + return reinterpret_cast<const T*>(reinterpret_cast<uintptr_t>(elf_header) + + offset); + } + +// ELF note name and desc are 32-bits word padded. +#define NOTE_PADDING(a) ((a + 3) & ~3) + + static bool ElfClassBuildIDNoteIdentifier(const void* section, size_t length, + std::vector<uint8_t>& identifier) { + static_assert(sizeof(ElfClass32::Nhdr) == sizeof(ElfClass64::Nhdr), + "Elf32_Nhdr and Elf64_Nhdr should be the same"); + typedef typename ElfClass32::Nhdr Nhdr; + + const void* section_end = reinterpret_cast<const char*>(section) + length; + const Nhdr* note_header = reinterpret_cast<const Nhdr*>(section); + while (reinterpret_cast<const void*>(note_header) < section_end) { + if (note_header->n_type == NT_GNU_BUILD_ID) break; + note_header = reinterpret_cast<const Nhdr*>( + reinterpret_cast<const char*>(note_header) + sizeof(Nhdr) + + NOTE_PADDING(note_header->n_namesz) + + NOTE_PADDING(note_header->n_descsz)); + } + if (reinterpret_cast<const void*>(note_header) >= section_end || + note_header->n_descsz == 0) { + return false; + } + + const uint8_t* build_id = reinterpret_cast<const uint8_t*>(note_header) + + sizeof(Nhdr) + + NOTE_PADDING(note_header->n_namesz); + identifier.insert(identifier.end(), build_id, + build_id + note_header->n_descsz); + + return true; + } + + template <typename ElfClass> + static bool FindElfClassSection(const char* elf_base, + const char* section_name, + typename ElfClass::Word section_type, + const void** section_start, + size_t* section_size) { + typedef typename ElfClass::Ehdr Ehdr; + typedef typename ElfClass::Shdr Shdr; + + if (!elf_base || !section_start || !section_size) { + return false; + } + + if (strncmp(elf_base, ELFMAG, SELFMAG) != 0) { + return false; + } + + const Ehdr* elf_header = reinterpret_cast<const Ehdr*>(elf_base); + if (elf_header->e_ident[EI_CLASS] != ElfClass::kClass) { + return false; + } + + const Shdr* sections = + GetOffset<ElfClass, Shdr>(elf_header, elf_header->e_shoff); + const Shdr* section_names = sections + elf_header->e_shstrndx; + const char* names = + GetOffset<ElfClass, char>(elf_header, section_names->sh_offset); + const char* names_end = names + section_names->sh_size; + + const Shdr* section = + FindElfSectionByName<ElfClass>(section_name, section_type, sections, + names, names_end, elf_header->e_shnum); + + if (section != NULL && section->sh_size > 0) { + *section_start = elf_base + section->sh_offset; + *section_size = section->sh_size; + } + + return true; + } + + template <typename ElfClass> + static bool FindElfClassSegment(const char* elf_base, + typename ElfClass::Word segment_type, + std::vector<ElfSegment>* segments) { + typedef typename ElfClass::Ehdr Ehdr; + typedef typename ElfClass::Phdr Phdr; + + if (!elf_base || !segments) { + return false; + } + + if (strncmp(elf_base, ELFMAG, SELFMAG) != 0) { + return false; + } + + const Ehdr* elf_header = reinterpret_cast<const Ehdr*>(elf_base); + if (elf_header->e_ident[EI_CLASS] != ElfClass::kClass) { + return false; + } + + const Phdr* phdrs = + GetOffset<ElfClass, Phdr>(elf_header, elf_header->e_phoff); + + for (int i = 0; i < elf_header->e_phnum; ++i) { + if (phdrs[i].p_type == segment_type) { + ElfSegment seg = {}; + seg.start = elf_base + phdrs[i].p_offset; + seg.size = phdrs[i].p_filesz; + segments->push_back(seg); + } + } + + return true; + } + + static bool IsValidElf(const void* elf_base) { + return strncmp(reinterpret_cast<const char*>(elf_base), ELFMAG, SELFMAG) == + 0; + } + + static int ElfClass(const void* elf_base) { + const ElfW(Ehdr)* elf_header = + reinterpret_cast<const ElfW(Ehdr)*>(elf_base); + + return elf_header->e_ident[EI_CLASS]; + } + + static bool FindElfSection(const void* elf_mapped_base, + const char* section_name, uint32_t section_type, + const void** section_start, size_t* section_size) { + if (!elf_mapped_base || !section_start || !section_size) { + return false; + } + + *section_start = NULL; + *section_size = 0; + + if (!IsValidElf(elf_mapped_base)) return false; + + int cls = ElfClass(elf_mapped_base); + const char* elf_base = static_cast<const char*>(elf_mapped_base); + + if (cls == ELFCLASS32) { + return FindElfClassSection<ElfClass32>(elf_base, section_name, + section_type, section_start, + section_size) && + *section_start != NULL; + } else if (cls == ELFCLASS64) { + return FindElfClassSection<ElfClass64>(elf_base, section_name, + section_type, section_start, + section_size) && + *section_start != NULL; + } + + return false; + } + + static bool FindElfSegments(const void* elf_mapped_base, + uint32_t segment_type, + std::vector<ElfSegment>* segments) { + if (!elf_mapped_base || !segments) { + return false; + } + + if (!IsValidElf(elf_mapped_base)) return false; + + int cls = ElfClass(elf_mapped_base); + const char* elf_base = static_cast<const char*>(elf_mapped_base); + + if (cls == ELFCLASS32) { + return FindElfClassSegment<ElfClass32>(elf_base, segment_type, segments); + } + if (cls == ELFCLASS64) { + return FindElfClassSegment<ElfClass64>(elf_base, segment_type, segments); + } + + return false; + } + + // Attempt to locate a .note.gnu.build-id section in an ELF binary + // and copy it into |identifier|. + static bool FindElfBuildIDNote(const void* elf_mapped_base, + std::vector<uint8_t>& identifier) { + // lld normally creates 2 PT_NOTEs, gold normally creates 1. + std::vector<ElfSegment> segs; + if (FindElfSegments(elf_mapped_base, PT_NOTE, &segs)) { + for (ElfSegment& seg : segs) { + if (ElfClassBuildIDNoteIdentifier(seg.start, seg.size, identifier)) { + return true; + } + } + } + + void* note_section; + size_t note_size; + if (FindElfSection(elf_mapped_base, ".note.gnu.build-id", SHT_NOTE, + (const void**)¬e_section, ¬e_size)) { + return ElfClassBuildIDNoteIdentifier(note_section, note_size, identifier); + } + + return false; + } + + // Attempt to locate the .text section of an ELF binary and generate + // a simple hash by XORing the first page worth of bytes into |identifier|. + static bool HashElfTextSection(const void* elf_mapped_base, + std::vector<uint8_t>& identifier) { + identifier.resize(kMDGUIDSize); + + void* text_section; + size_t text_size; + if (!FindElfSection(elf_mapped_base, ".text", SHT_PROGBITS, + (const void**)&text_section, &text_size) || + text_size == 0) { + return false; + } + + // Only provide |kMDGUIDSize| bytes to keep identifiers produced by this + // function backwards-compatible. + memset(&identifier[0], 0, kMDGUIDSize); + const uint8_t* ptr = reinterpret_cast<const uint8_t*>(text_section); + const uint8_t* ptr_end = + ptr + std::min(text_size, static_cast<size_t>(4096)); + while (ptr < ptr_end) { + for (unsigned i = 0; i < kMDGUIDSize; i++) identifier[i] ^= ptr[i]; + ptr += kMDGUIDSize; + } + return true; + } + + // Load the identifier for the elf file mapped into memory at |base| into + // |identifier|. Return false if the identifier could not be created for this + // file. + static bool ElfFileIdentifierFromMappedFile( + const void* base, std::vector<uint8_t>& identifier) { + // Look for a build id note first. + if (FindElfBuildIDNote(base, identifier)) return true; + + // Fall back on hashing the first page of the text section. + return HashElfTextSection(base, identifier); + } + + // These three functions are not ever called in an unsafe context, so it's OK + // to allocate memory and use libc. + static std::string bytes_to_hex_string(const uint8_t* bytes, size_t count, + bool lowercase = false) { + std::string result; + for (unsigned int idx = 0; idx < count; ++idx) { + char buf[3]; + SprintfLiteral(buf, lowercase ? "%02x" : "%02X", bytes[idx]); + result.append(buf); + } + return result; + } + + // Convert the |identifier| data to a string. The string will + // be formatted as a UUID in all uppercase without dashes. + // (e.g., 22F065BBFC9C49F780FE26A7CEBD7BCE). + static std::string ConvertIdentifierToUUIDString( + const std::vector<uint8_t>& identifier) { + uint8_t identifier_swapped[kMDGUIDSize] = {0}; + + // Endian-ness swap to match dump processor expectation. + memcpy(identifier_swapped, &identifier[0], + std::min(kMDGUIDSize, identifier.size())); + uint32_t* data1 = reinterpret_cast<uint32_t*>(identifier_swapped); + *data1 = htonl(*data1); + uint16_t* data2 = reinterpret_cast<uint16_t*>(identifier_swapped + 4); + *data2 = htons(*data2); + uint16_t* data3 = reinterpret_cast<uint16_t*>(identifier_swapped + 6); + *data3 = htons(*data3); + + return bytes_to_hex_string(identifier_swapped, kMDGUIDSize); + } + + // Convert the entire |identifier| data to a lowercase hex string. + static std::string ConvertIdentifierToString( + const std::vector<uint8_t>& identifier) { + return bytes_to_hex_string(&identifier[0], identifier.size(), + /* lowercase */ true); + } + + private: + // Storage for the path specified + std::string path_; +}; + +// End of imports from toolkit/crashreporter/google-breakpad/. +// ---------------------------------------------------------------------------- + +struct LoadedLibraryInfo { + LoadedLibraryInfo(const char* aName, unsigned long aBaseAddress, + unsigned long aFirstMappingStart, + unsigned long aLastMappingEnd) + : mName(aName), + mBaseAddress(aBaseAddress), + mFirstMappingStart(aFirstMappingStart), + mLastMappingEnd(aLastMappingEnd) {} + + std::string mName; + unsigned long mBaseAddress; + unsigned long mFirstMappingStart; + unsigned long mLastMappingEnd; +}; + +static std::string IDtoUUIDString(const std::vector<uint8_t>& aIdentifier) { + std::string uuid = FileID::ConvertIdentifierToUUIDString(aIdentifier); + // This is '0', not '\0', since it represents the breakpad id age. + uuid += '0'; + return uuid; +} + +// Return raw Build ID in hex. +static std::string IDtoString(const std::vector<uint8_t>& aIdentifier) { + std::string uuid = FileID::ConvertIdentifierToString(aIdentifier); + return uuid; +} + +// Get the breakpad Id for the binary file pointed by bin_name +static std::string getBreakpadId(const char* bin_name) { + std::vector<uint8_t> identifier; + identifier.reserve(kDefaultBuildIdSize); + + FileID file_id(bin_name); + if (file_id.ElfFileIdentifier(identifier)) { + return IDtoUUIDString(identifier); + } + + return {}; +} + +// Get the code Id for the binary file pointed by bin_name +static std::string getCodeId(const char* bin_name) { + std::vector<uint8_t> identifier; + identifier.reserve(kDefaultBuildIdSize); + + FileID file_id(bin_name); + if (file_id.ElfFileIdentifier(identifier)) { + return IDtoString(identifier); + } + + return {}; +} + +static SharedLibrary SharedLibraryAtPath(const char* path, + unsigned long libStart, + unsigned long libEnd, + unsigned long offset = 0) { + std::string pathStr = path; + + size_t pos = pathStr.rfind('\\'); + std::string nameStr = + (pos != std::string::npos) ? pathStr.substr(pos + 1) : pathStr; + + return SharedLibrary(libStart, libEnd, offset, getBreakpadId(path), + getCodeId(path), nameStr, pathStr, nameStr, pathStr, + std::string{}, ""); +} + +static int dl_iterate_callback(struct dl_phdr_info* dl_info, size_t size, + void* data) { + auto libInfoList = reinterpret_cast<std::vector<LoadedLibraryInfo>*>(data); + + if (dl_info->dlpi_phnum <= 0) return 0; + + unsigned long baseAddress = dl_info->dlpi_addr; + unsigned long firstMappingStart = -1; + unsigned long lastMappingEnd = 0; + + for (size_t i = 0; i < dl_info->dlpi_phnum; i++) { + if (dl_info->dlpi_phdr[i].p_type != PT_LOAD) { + continue; + } + unsigned long start = dl_info->dlpi_addr + dl_info->dlpi_phdr[i].p_vaddr; + unsigned long end = start + dl_info->dlpi_phdr[i].p_memsz; + if (start < firstMappingStart) { + firstMappingStart = start; + } + if (end > lastMappingEnd) { + lastMappingEnd = end; + } + } + + libInfoList->push_back(LoadedLibraryInfo(dl_info->dlpi_name, baseAddress, + firstMappingStart, lastMappingEnd)); + + return 0; +} + +SharedLibraryInfo SharedLibraryInfo::GetInfoForSelf() { + SharedLibraryInfo info; + +#if defined(GP_OS_linux) + // We need to find the name of the executable (exeName, exeNameLen) and the + // address of its executable section (exeExeAddr) in the running image. + char exeName[PATH_MAX]; + memset(exeName, 0, sizeof(exeName)); + + ssize_t exeNameLen = readlink("/proc/self/exe", exeName, sizeof(exeName) - 1); + if (exeNameLen == -1) { + // readlink failed for whatever reason. Note this, but keep going. + exeName[0] = '\0'; + exeNameLen = 0; + // LOG("SharedLibraryInfo::GetInfoForSelf(): readlink failed"); + } else { + // Assert no buffer overflow. + MOZ_RELEASE_ASSERT(exeNameLen >= 0 && + exeNameLen < static_cast<ssize_t>(sizeof(exeName))); + } + + unsigned long exeExeAddr = 0; +#endif + +#if defined(GP_OS_android) + // If dl_iterate_phdr doesn't exist, we give up immediately. + if (!dl_iterate_phdr) { + // On ARM Android, dl_iterate_phdr is provided by the custom linker. + // So if libxul was loaded by the system linker (e.g. as part of + // xpcshell when running tests), it won't be available and we should + // not call it. + return info; + } +#endif + +#if defined(GP_OS_linux) || defined(GP_OS_android) + // Read info from /proc/self/maps. We ignore most of it. + pid_t pid = mozilla::baseprofiler::profiler_current_process_id().ToNumber(); + char path[PATH_MAX]; + SprintfLiteral(path, "/proc/%d/maps", pid); + std::ifstream maps(path); + std::string line; + while (std::getline(maps, line)) { + int ret; + unsigned long start; + unsigned long end; + char perm[6 + 1] = ""; + unsigned long offset; + char modulePath[PATH_MAX + 1] = ""; + ret = sscanf(line.c_str(), + "%lx-%lx %6s %lx %*s %*x %" PATH_MAX_STRING(PATH_MAX) "s\n", + &start, &end, perm, &offset, modulePath); + if (!strchr(perm, 'x')) { + // Ignore non executable entries + continue; + } + if (ret != 5 && ret != 4) { + // LOG("SharedLibraryInfo::GetInfoForSelf(): " + // "reading /proc/self/maps failed"); + continue; + } + +# if defined(GP_OS_linux) + // Try to establish the main executable's load address. + if (exeNameLen > 0 && strcmp(modulePath, exeName) == 0) { + exeExeAddr = start; + } +# elif defined(GP_OS_android) + // Use /proc/pid/maps to get the dalvik-jit section since it has no + // associated phdrs. + if (0 == strcmp(modulePath, "/dev/ashmem/dalvik-jit-code-cache")) { + info.AddSharedLibrary( + SharedLibraryAtPath(modulePath, start, end, offset)); + if (info.GetSize() > 10000) { + // LOG("SharedLibraryInfo::GetInfoForSelf(): " + // "implausibly large number of mappings acquired"); + break; + } + } +# endif + } +#endif + + std::vector<LoadedLibraryInfo> libInfoList; + + // We collect the bulk of the library info using dl_iterate_phdr. + dl_iterate_phdr(dl_iterate_callback, &libInfoList); + + for (const auto& libInfo : libInfoList) { + info.AddSharedLibrary( + SharedLibraryAtPath(libInfo.mName.c_str(), libInfo.mFirstMappingStart, + libInfo.mLastMappingEnd, + libInfo.mFirstMappingStart - libInfo.mBaseAddress)); + } + +#if defined(GP_OS_linux) + // Make another pass over the information we just harvested from + // dl_iterate_phdr. If we see a nameless object mapped at what we earlier + // established to be the main executable's load address, attach the + // executable's name to that entry. + for (size_t i = 0; i < info.GetSize(); i++) { + SharedLibrary& lib = info.GetMutableEntry(i); + if (lib.GetStart() <= exeExeAddr && exeExeAddr <= lib.GetEnd() && + lib.GetDebugPath().empty()) { + lib = SharedLibraryAtPath(exeName, lib.GetStart(), lib.GetEnd(), + lib.GetOffset()); + + // We only expect to see one such entry. + break; + } + } +#endif + + return info; +} + +void SharedLibraryInfo::Initialize() { /* do nothing */ +} |