From 3a7466663c7b8ddc550a96666c2a14c82d91536f Mon Sep 17 00:00:00 2001 From: "mark@chromium.org" Date: Fri, 27 Aug 2010 18:52:09 +0000 Subject: [PATCH] Linux FileID should work with ELFCLASS32 and ELFCLASS64 regardless of what's native. BUG=399 TEST=none Review URL: http://breakpad.appspot.com/178001 git-svn-id: http://google-breakpad.googlecode.com/svn/trunk@677 4c0a9323-5329-0410-9bdc-e9ce6186880e --- src/common/linux/file_id.cc | 81 +++++++++++++++++++--------- src/common/linux/file_id_unittest.cc | 67 +++++++++++++++++++++++ 2 files changed, 123 insertions(+), 25 deletions(-) diff --git a/src/common/linux/file_id.cc b/src/common/linux/file_id.cc index d2461b9c..a4e3a6e3 100644 --- a/src/common/linux/file_id.cc +++ b/src/common/linux/file_id.cc @@ -56,37 +56,44 @@ FileID::FileID(const char* path) { strncpy(path_, path, sizeof(path_)); } -// These two functions are also used inside the crashed process, so be safe +struct ElfClass32 { + typedef Elf32_Ehdr Ehdr; + typedef Elf32_Shdr Shdr; + static const int kClass = ELFCLASS32; +}; + +struct ElfClass64 { + typedef Elf64_Ehdr Ehdr; + typedef Elf64_Shdr Shdr; + static const int kClass = ELFCLASS64; +}; + +// These three functions are also used inside the crashed process, so be safe // and use the syscall/libc wrappers instead of direct syscalls or libc. - static bool FindElfTextSection(const void *elf_mapped_base, - const void **text_start, - int *text_size) { - assert(elf_mapped_base); +template +static void FindElfClassTextSection(const char *elf_base, + const void **text_start, + int *text_size) { + typedef typename ElfClass::Ehdr Ehdr; + typedef typename ElfClass::Shdr Shdr; + + assert(elf_base); assert(text_start); assert(text_size); - const char* elf_base = - static_cast(elf_mapped_base); - const ElfW(Ehdr)* elf_header = - reinterpret_cast(elf_base); - if (my_strncmp(elf_base, ELFMAG, SELFMAG) != 0) - return false; -#if __ELF_NATIVE_CLASS == 32 -#define ELFCLASS ELFCLASS32 -#else -#define ELFCLASS ELFCLASS64 -#endif - //TODO: support dumping 32-bit binaries from a 64-bit dump_syms? - if (elf_header->e_ident[EI_CLASS] != ELFCLASS) - return false; - *text_start = NULL; - *text_size = 0; - const ElfW(Shdr)* sections = - reinterpret_cast(elf_base + elf_header->e_shoff); + assert(my_strncmp(elf_base, ELFMAG, SELFMAG) == 0); + const char* text_section_name = ".text"; int name_len = my_strlen(text_section_name); - const ElfW(Shdr)* string_section = sections + elf_header->e_shstrndx; - const ElfW(Shdr)* text_section = NULL; + + const Ehdr* elf_header = reinterpret_cast(elf_base); + assert(elf_header->e_ident[EI_CLASS] == ElfClass::kClass); + + const Shdr* sections = + reinterpret_cast(elf_base + elf_header->e_shoff); + const Shdr* string_section = sections + elf_header->e_shstrndx; + + const Shdr* text_section = NULL; for (int i = 0; i < elf_header->e_shnum; ++i) { if (sections[i].sh_type == SHT_PROGBITS) { const char* section_name = (char*)(elf_base + @@ -102,6 +109,30 @@ FileID::FileID(const char* path) { *text_start = elf_base + text_section->sh_offset; *text_size = text_section->sh_size; } +} + +static bool FindElfTextSection(const void *elf_mapped_base, + const void **text_start, + int *text_size) { + assert(elf_mapped_base); + assert(text_start); + assert(text_size); + + const char* elf_base = + static_cast(elf_mapped_base); + const ElfW(Ehdr)* elf_header = + reinterpret_cast(elf_base); + if (my_strncmp(elf_base, ELFMAG, SELFMAG) != 0) + return false; + + if (elf_header->e_ident[EI_CLASS] == ELFCLASS32) { + FindElfClassTextSection(elf_base, text_start, text_size); + } else if (elf_header->e_ident[EI_CLASS] == ELFCLASS64) { + FindElfClassTextSection(elf_base, text_start, text_size); + } else { + return false; + } + return true; } diff --git a/src/common/linux/file_id_unittest.cc b/src/common/linux/file_id_unittest.cc index e15d39fb..e28a2f09 100644 --- a/src/common/linux/file_id_unittest.cc +++ b/src/common/linux/file_id_unittest.cc @@ -29,6 +29,7 @@ // Unit tests for FileID +#include #include #include "common/linux/file_id.h" @@ -74,3 +75,69 @@ TEST(FileIDTest, FileIDStrip) { EXPECT_STREQ(identifier_string1, identifier_string2); unlink(templ); } + +struct ElfClass32 { + typedef Elf32_Ehdr Ehdr; + typedef Elf32_Shdr Shdr; + static const int kClass = ELFCLASS32; +}; + +struct ElfClass64 { + typedef Elf64_Ehdr Ehdr; + typedef Elf64_Shdr Shdr; + static const int kClass = ELFCLASS64; +}; + +template +struct ElfishElf { + typedef typename ElfClass::Ehdr Ehdr; + typedef typename ElfClass::Shdr Shdr; + + Ehdr elf_header; + Shdr text_header; + Shdr string_header; + char text_section[128]; + char string_section[8]; + + static void Populate(ElfishElf* elf) { + memset(elf, 0, sizeof(ElfishElf)); + memcpy(elf, ELFMAG, SELFMAG); + elf->elf_header.e_ident[EI_CLASS] = ElfClass::kClass; + elf->elf_header.e_shoff = offsetof(ElfishElf, text_header); + elf->elf_header.e_shnum = 2; + elf->elf_header.e_shstrndx = 1; + elf->text_header.sh_name = 0; + elf->text_header.sh_type = SHT_PROGBITS; + elf->text_header.sh_offset = offsetof(ElfishElf, text_section); + elf->text_header.sh_size = sizeof(text_section); + for (size_t i = 0; i < sizeof(text_section); ++i) { + elf->text_section[i] = i * 3; + } + elf->string_header.sh_offset = offsetof(ElfishElf, string_section); + strcpy(elf->string_section, ".text"); + } +}; + +TEST(FileIDTest, ElfClass) { + uint8_t identifier[sizeof(MDGUID)]; + const char expected_identifier_string[] = + "80808080-8080-0000-0000-008080808080"; + char identifier_string[sizeof(expected_identifier_string)]; + + ElfishElf elf32; + ElfishElf::Populate(&elf32); + EXPECT_TRUE(FileID::ElfFileIdentifierFromMappedFile(&elf32, identifier)); + FileID::ConvertIdentifierToString(identifier, identifier_string, + sizeof(identifier_string)); + EXPECT_STREQ(expected_identifier_string, identifier_string); + + memset(identifier, 0, sizeof(identifier)); + memset(identifier_string, 0, sizeof(identifier_string)); + + ElfishElf elf64; + ElfishElf::Populate(&elf64); + EXPECT_TRUE(FileID::ElfFileIdentifierFromMappedFile(&elf64, identifier)); + FileID::ConvertIdentifierToString(identifier, identifier_string, + sizeof(identifier_string)); + EXPECT_STREQ(expected_identifier_string, identifier_string); +}