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// Copyright (c) 2010 Google Inc.
// All rights reserved.
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are
// met:
//
// * Redistributions of source code must retain the above copyright
// notice, this list of conditions and the following disclaimer.
// * Redistributions in binary form must reproduce the above
// copyright notice, this list of conditions and the following disclaimer
// in the documentation and/or other materials provided with the
// distribution.
// * Neither the name of Google Inc. nor the names of its
// contributors may be used to endorse or promote products derived from
// this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
// Author: Alfred Peng
#include <demangle.h>
#include <fcntl.h>
#include <gelf.h>
#include <link.h>
#include <sys/mman.h>
#include <stab.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <unistd.h>
#include <functional>
#include <map>
#include <vector>
#include "common/scoped_ptr.h"
#include "common/solaris/dump_symbols.h"
#include "common/solaris/file_id.h"
#include "common/solaris/guid_creator.h"
// This namespace contains helper functions.
namespace {
using std::make_pair;
#if defined(_LP64)
typedef Elf64_Sym Elf_Sym;
#else
typedef Elf32_Sym Elf_Sym;
#endif
// Symbol table entry from stabs. Sun CC specific.
struct slist {
// String table index.
unsigned int n_strx;
// Stab type.
unsigned char n_type;
char n_other;
short n_desc;
unsigned long n_value;
};
// Symbol table entry
struct SymbolEntry {
// Offset from the start of the file.
GElf_Addr offset;
// Function size.
GElf_Word size;
};
// Infomation of a line.
struct LineInfo {
// Offset from start of the function.
// Load from stab symbol.
GElf_Off rva_to_func;
// Offset from base of the loading binary.
GElf_Off rva_to_base;
// Size of the line.
// The first line: equals to rva_to_func.
// The other lines: the difference of rva_to_func of the line and
// rva_to_func of the previous N_SLINE.
uint32_t size;
// Line number.
uint32_t line_num;
};
// Information of a function.
struct FuncInfo {
// Name of the function.
const char *name;
// Offset from the base of the loading address.
GElf_Off rva_to_base;
// Virtual address of the function.
// Load from stab symbol.
GElf_Addr addr;
// Size of the function.
// Equal to rva_to_func of the last function line.
uint32_t size;
// Total size of stack parameters.
uint32_t stack_param_size;
// Line information array.
std::vector<struct LineInfo> line_info;
};
// Information of a source file.
struct SourceFileInfo {
// Name of the source file.
const char *name;
// Starting address of the source file.
GElf_Addr addr;
// Id of the source file.
int source_id;
// Functions information.
std::vector<struct FuncInfo> func_info;
};
struct CompareString {
bool operator()(const char *s1, const char *s2) const {
return strcmp(s1, s2) < 0;
}
};
typedef std::map<const char *, struct SymbolEntry *, CompareString> SymbolMap;
// Information of a symbol table.
// This is the root of all types of symbol.
struct SymbolInfo {
std::vector<struct SourceFileInfo> source_file_info;
// Symbols information.
SymbolMap symbol_entries;
};
// Stab section name.
const char *kStabName = ".stab";
// Stab str section name.
const char *kStabStrName = ".stabstr";
// Symtab section name.
const char *kSymtabName = ".symtab";
// Strtab section name.
const char *kStrtabName = ".strtab";
// Default buffer lenght for demangle.
const int demangleLen = 20000;
// Offset to the string table.
uint64_t stringOffset = 0;
// Update the offset to the start of the string index of the next
// object module for every N_ENDM stabs.
inline void RecalculateOffset(struct slist* cur_list, char *stabstr) {
while ((--cur_list)->n_strx == 0) ;
stringOffset += cur_list->n_strx;
char *temp = stabstr + stringOffset;
while (*temp != '\0') {
++stringOffset;
++temp;
}
// Skip the extra '\0'
++stringOffset;
}
// Demangle using demangle library on Solaris.
std::string Demangle(const char *mangled) {
int status = 0;
std::string str(mangled);
char *demangled = (char *)malloc(demangleLen);
if (!demangled) {
fprintf(stderr, "no enough memory.\n");
goto out;
}
if ((status = cplus_demangle(mangled, demangled, demangleLen)) ==
DEMANGLE_ESPACE) {
fprintf(stderr, "incorrect demangle.\n");
goto out;
}
str = demangled;
free(demangled);
out:
return str;
}
bool WriteFormat(int fd, const char *fmt, ...) {
va_list list;
char buffer[4096];
ssize_t expected, written;
va_start(list, fmt);
vsnprintf(buffer, sizeof(buffer), fmt, list);
expected = strlen(buffer);
written = write(fd, buffer, strlen(buffer));
va_end(list);
return expected == written;
}
bool IsValidElf(const GElf_Ehdr *elf_header) {
return memcmp(elf_header, ELFMAG, SELFMAG) == 0;
}
static bool FindSectionByName(Elf *elf, const char *name,
int shstrndx,
GElf_Shdr *shdr) {
assert(name != NULL);
if (strlen(name) == 0)
return false;
Elf_Scn *scn = NULL;
while ((scn = elf_nextscn(elf, scn)) != NULL) {
if (gelf_getshdr(scn, shdr) == (GElf_Shdr *)0) {
fprintf(stderr, "failed to read section header: %s\n", elf_errmsg(0));
return false;
}
const char *section_name = elf_strptr(elf, shstrndx, shdr->sh_name);
if (!section_name) {
fprintf(stderr, "Section name error: %s\n", elf_errmsg(-1));
continue;
}
if (strcmp(section_name, name) == 0)
return true;
}
return false;
}
// The parameter size is used for FPO-optimized code, and
// this is all tied up with the debugging data for Windows x86.
// Set it to 0 on Solaris.
int LoadStackParamSize(struct slist *list,
struct slist *list_end,
struct FuncInfo *func_info) {
struct slist *cur_list = list;
int step = 1;
while (cur_list < list_end && cur_list->n_type == N_PSYM) {
++cur_list;
++step;
}
func_info->stack_param_size = 0;
return step;
}
int LoadLineInfo(struct slist *list,
struct slist *list_end,
struct FuncInfo *func_info) {
struct slist *cur_list = list;
do {
// Skip non line information.
while (cur_list < list_end && cur_list->n_type != N_SLINE) {
// Only exit when got another function, or source file, or end stab.
if (cur_list->n_type == N_FUN || cur_list->n_type == N_SO ||
cur_list->n_type == N_ENDM) {
return cur_list - list;
}
++cur_list;
}
struct LineInfo line;
while (cur_list < list_end && cur_list->n_type == N_SLINE) {
line.rva_to_func = cur_list->n_value;
// n_desc is a signed short
line.line_num = (unsigned short)cur_list->n_desc;
func_info->line_info.push_back(line);
++cur_list;
}
if (cur_list == list_end && cur_list->n_type == N_ENDM)
break;
} while (list < list_end);
return cur_list - list;
}
int LoadFuncSymbols(struct slist *list,
struct slist *list_end,
char *stabstr,
GElf_Word base,
struct SourceFileInfo *source_file_info) {
struct slist *cur_list = list;
assert(cur_list->n_type == N_SO);
++cur_list;
source_file_info->func_info.clear();
while (cur_list < list_end) {
// Go until the function symbol.
while (cur_list < list_end && cur_list->n_type != N_FUN) {
if (cur_list->n_type == N_SO) {
return cur_list - list;
}
++cur_list;
if (cur_list->n_type == N_ENDM)
RecalculateOffset(cur_list, stabstr);
continue;
}
while (cur_list->n_type == N_FUN) {
struct FuncInfo func_info;
memset(&func_info, 0, sizeof(func_info));
func_info.name = stabstr + cur_list->n_strx + stringOffset;
// The n_value field is always 0 from stab generated by Sun CC.
// TODO(Alfred): Find the correct value.
func_info.addr = cur_list->n_value;
++cur_list;
if (cur_list->n_type == N_ENDM)
RecalculateOffset(cur_list, stabstr);
if (cur_list->n_type != N_ESYM && cur_list->n_type != N_ISYM &&
cur_list->n_type != N_FUN) {
// Stack parameter size.
cur_list += LoadStackParamSize(cur_list, list_end, &func_info);
// Line info.
cur_list += LoadLineInfo(cur_list, list_end, &func_info);
}
if (cur_list < list_end && cur_list->n_type == N_ENDM)
RecalculateOffset(cur_list, stabstr);
// Functions in this module should have address bigger than the module
// starting address.
//
// These two values are always 0 with Sun CC.
// TODO(Alfred): Get the correct value or remove the condition statement.
if (func_info.addr >= source_file_info->addr) {
source_file_info->func_info.push_back(func_info);
}
}
}
return cur_list - list;
}
// Compute size and rva information based on symbols loaded from stab section.
bool ComputeSizeAndRVA(struct SymbolInfo *symbols) {
std::vector<struct SourceFileInfo> *sorted_files =
&(symbols->source_file_info);
SymbolMap *symbol_entries = &(symbols->symbol_entries);
for (size_t i = 0; i < sorted_files->size(); ++i) {
struct SourceFileInfo &source_file = (*sorted_files)[i];
std::vector<struct FuncInfo> *sorted_functions = &(source_file.func_info);
int func_size = sorted_functions->size();
for (size_t j = 0; j < func_size; ++j) {
struct FuncInfo &func_info = (*sorted_functions)[j];
int line_count = func_info.line_info.size();
// Discard the ending part of the name.
std::string func_name(func_info.name);
std::string::size_type last_colon = func_name.find_first_of(':');
if (last_colon != std::string::npos)
func_name = func_name.substr(0, last_colon);
// Fine the symbol offset from the loading address and size by name.
SymbolMap::const_iterator it = symbol_entries->find(func_name.c_str());
if (it->second) {
func_info.rva_to_base = it->second->offset;
func_info.size = (line_count == 0) ? 0 : it->second->size;
} else {
func_info.rva_to_base = 0;
func_info.size = 0;
}
// Compute function and line size.
for (size_t k = 0; k < line_count; ++k) {
struct LineInfo &line_info = func_info.line_info[k];
line_info.rva_to_base = line_info.rva_to_func + func_info.rva_to_base;
if (k == line_count - 1) {
line_info.size = func_info.size - line_info.rva_to_func;
} else {
struct LineInfo &next_line = func_info.line_info[k + 1];
line_info.size = next_line.rva_to_func - line_info.rva_to_func;
}
} // for each line.
} // for each function.
} // for each source file.
for (SymbolMap::iterator it = symbol_entries->begin();
it != symbol_entries->end(); ++it) {
free(it->second);
}
return true;
}
bool LoadAllSymbols(const GElf_Shdr *stab_section,
const GElf_Shdr *stabstr_section,
GElf_Word base,
struct SymbolInfo *symbols) {
if (stab_section == NULL || stabstr_section == NULL)
return false;
char *stabstr =
reinterpret_cast<char *>(stabstr_section->sh_offset + base);
struct slist *lists =
reinterpret_cast<struct slist *>(stab_section->sh_offset + base);
int nstab = stab_section->sh_size / sizeof(struct slist);
int source_id = 0;
// First pass, load all symbols from the object file.
for (int i = 0; i < nstab; ) {
int step = 1;
struct slist *cur_list = lists + i;
if (cur_list->n_type == N_SO) {
// FUNC <address> <size> <param_stack_size> <function>
struct SourceFileInfo source_file_info;
source_file_info.name = stabstr + cur_list->n_strx + stringOffset;
// The n_value field is always 0 from stab generated by Sun CC.
// TODO(Alfred): Find the correct value.
source_file_info.addr = cur_list->n_value;
if (strchr(source_file_info.name, '.'))
source_file_info.source_id = source_id++;
else
source_file_info.source_id = -1;
step = LoadFuncSymbols(cur_list, lists + nstab - 1, stabstr,
base, &source_file_info);
symbols->source_file_info.push_back(source_file_info);
}
i += step;
}
// Second pass, compute the size of functions and lines.
return ComputeSizeAndRVA(symbols);
}
bool LoadSymbols(Elf *elf, GElf_Ehdr *elf_header, struct SymbolInfo *symbols,
void *obj_base) {
GElf_Word base = reinterpret_cast<GElf_Word>(obj_base);
const GElf_Shdr *sections =
reinterpret_cast<GElf_Shdr *>(elf_header->e_shoff + base);
GElf_Shdr stab_section;
if (!FindSectionByName(elf, kStabName, elf_header->e_shstrndx,
&stab_section)) {
fprintf(stderr, "Stab section not found.\n");
return false;
}
GElf_Shdr stabstr_section;
if (!FindSectionByName(elf, kStabStrName, elf_header->e_shstrndx,
&stabstr_section)) {
fprintf(stderr, "Stabstr section not found.\n");
return false;
}
GElf_Shdr symtab_section;
if (!FindSectionByName(elf, kSymtabName, elf_header->e_shstrndx,
&symtab_section)) {
fprintf(stderr, "Symtab section not found.\n");
return false;
}
GElf_Shdr strtab_section;
if (!FindSectionByName(elf, kStrtabName, elf_header->e_shstrndx,
&strtab_section)) {
fprintf(stderr, "Strtab section not found.\n");
return false;
}
Elf_Sym *symbol = (Elf_Sym *)((char *)base + symtab_section.sh_offset);
for (int i = 0; i < symtab_section.sh_size/symtab_section.sh_entsize; ++i) {
struct SymbolEntry *symbol_entry =
(struct SymbolEntry *)malloc(sizeof(struct SymbolEntry));
const char *name = reinterpret_cast<char *>(
strtab_section.sh_offset + (GElf_Word)base + symbol->st_name);
symbol_entry->offset = symbol->st_value;
symbol_entry->size = symbol->st_size;
symbols->symbol_entries.insert(make_pair(name, symbol_entry));
++symbol;
}
// Load symbols.
return LoadAllSymbols(&stab_section, &stabstr_section, base, symbols);
}
bool WriteModuleInfo(int fd, GElf_Half arch, const std::string &obj_file) {
const char *arch_name = NULL;
if (arch == EM_386)
arch_name = "x86";
else if (arch == EM_X86_64)
arch_name = "x86_64";
else if (arch == EM_SPARC32PLUS)
arch_name = "SPARC_32+";
else {
printf("Please add more ARCH support\n");
return false;
}
unsigned char identifier[16];
google_breakpad::FileID file_id(obj_file.c_str());
if (file_id.ElfFileIdentifier(identifier)) {
char identifier_str[40];
file_id.ConvertIdentifierToString(identifier,
identifier_str, sizeof(identifier_str));
std::string filename = obj_file;
size_t slash_pos = obj_file.find_last_of("/");
if (slash_pos != std::string::npos)
filename = obj_file.substr(slash_pos + 1);
return WriteFormat(fd, "MODULE solaris %s %s %s\n", arch_name,
identifier_str, filename.c_str());
}
return false;
}
bool WriteSourceFileInfo(int fd, const struct SymbolInfo &symbols) {
for (size_t i = 0; i < symbols.source_file_info.size(); ++i) {
if (symbols.source_file_info[i].source_id != -1) {
const char *name = symbols.source_file_info[i].name;
if (!WriteFormat(fd, "FILE %d %s\n",
symbols.source_file_info[i].source_id, name))
return false;
}
}
return true;
}
bool WriteOneFunction(int fd, int source_id,
const struct FuncInfo &func_info){
// Discard the ending part of the name.
std::string func_name(func_info.name);
std::string::size_type last_colon = func_name.find_last_of(':');
if (last_colon != std::string::npos)
func_name = func_name.substr(0, last_colon);
func_name = Demangle(func_name.c_str());
if (func_info.size <= 0)
return true;
// rva_to_base could be unsigned long(32 bit) or unsigned long long(64 bit).
if (WriteFormat(fd, "FUNC %llx %x %d %s\n",
(long long)func_info.rva_to_base,
func_info.size,
func_info.stack_param_size,
func_name.c_str())) {
for (size_t i = 0; i < func_info.line_info.size(); ++i) {
const struct LineInfo &line_info = func_info.line_info[i];
if (line_info.line_num == 0)
return true;
if (!WriteFormat(fd, "%llx %x %d %d\n",
(long long)line_info.rva_to_base,
line_info.size,
line_info.line_num,
source_id))
return false;
}
return true;
}
return false;
}
bool WriteFunctionInfo(int fd, const struct SymbolInfo &symbols) {
for (size_t i = 0; i < symbols.source_file_info.size(); ++i) {
const struct SourceFileInfo &file_info = symbols.source_file_info[i];
for (size_t j = 0; j < file_info.func_info.size(); ++j) {
const struct FuncInfo &func_info = file_info.func_info[j];
if (!WriteOneFunction(fd, file_info.source_id, func_info))
return false;
}
}
return true;
}
bool DumpStabSymbols(int fd, const struct SymbolInfo &symbols) {
return WriteSourceFileInfo(fd, symbols) &&
WriteFunctionInfo(fd, symbols);
}
//
// FDWrapper
//
// Wrapper class to make sure opened file is closed.
//
class FDWrapper {
public:
explicit FDWrapper(int fd) :
fd_(fd) {
}
~FDWrapper() {
if (fd_ != -1)
close(fd_);
}
int get() {
return fd_;
}
int release() {
int fd = fd_;
fd_ = -1;
return fd;
}
private:
int fd_;
};
//
// MmapWrapper
//
// Wrapper class to make sure mapped regions are unmapped.
//
class MmapWrapper {
public:
MmapWrapper(void *mapped_address, size_t mapped_size) :
base_(mapped_address), size_(mapped_size) {
}
~MmapWrapper() {
if (base_ != NULL) {
assert(size_ > 0);
munmap((char *)base_, size_);
}
}
void release() {
base_ = NULL;
size_ = 0;
}
private:
void *base_;
size_t size_;
};
} // namespace
namespace google_breakpad {
class AutoElfEnder {
public:
AutoElfEnder(Elf *elf) : elf_(elf) {}
~AutoElfEnder() { if (elf_) elf_end(elf_); }
private:
Elf *elf_;
};
bool DumpSymbols::WriteSymbolFile(const std::string &obj_file, int sym_fd) {
if (elf_version(EV_CURRENT) == EV_NONE) {
fprintf(stderr, "elf_version() failed: %s\n", elf_errmsg(0));
return false;
}
int obj_fd = open(obj_file.c_str(), O_RDONLY);
if (obj_fd < 0)
return false;
FDWrapper obj_fd_wrapper(obj_fd);
struct stat st;
if (fstat(obj_fd, &st) != 0 && st.st_size <= 0)
return false;
void *obj_base = mmap(NULL, st.st_size,
PROT_READ, MAP_PRIVATE, obj_fd, 0);
if (obj_base == MAP_FAILED)
return false;
MmapWrapper map_wrapper(obj_base, st.st_size);
GElf_Ehdr elf_header;
Elf *elf = elf_begin(obj_fd, ELF_C_READ, NULL);
AutoElfEnder elfEnder(elf);
if (gelf_getehdr(elf, &elf_header) == (GElf_Ehdr *)NULL) {
fprintf(stderr, "failed to read elf header: %s\n", elf_errmsg(-1));
return false;
}
if (!IsValidElf(&elf_header)) {
fprintf(stderr, "header magic doesn't match\n");
return false;
}
struct SymbolInfo symbols;
if (!LoadSymbols(elf, &elf_header, &symbols, obj_base))
return false;
// Write to symbol file.
if (WriteModuleInfo(sym_fd, elf_header.e_machine, obj_file) &&
DumpStabSymbols(sym_fd, symbols))
return true;
return false;
}
} // namespace google_breakpad