#if defined(HAVE_SYMBOLIZE)
+#include <string.h>
+
#include <limits>
#include "symbolize.h"
// both regular and dynamic symbol tables if necessary. On success,
// write the symbol name to "out" and return true. Otherwise, return
// false.
-static bool GetSymbolFromObjectFile(const int fd, uint64_t pc,
- char *out, int out_size,
- uint64_t map_start_address) {
+static bool GetSymbolFromObjectFile(const int fd,
+ uint64_t pc,
+ char* out,
+ int out_size,
+ uint64_t base_address) {
// Read the ELF header.
ElfW(Ehdr) elf_header;
if (!ReadFromOffsetExact(fd, &elf_header, sizeof(elf_header), 0)) {
return false;
}
- uint64_t symbol_offset = 0;
- if (elf_header.e_type == ET_DYN) { // DSO needs offset adjustment.
- symbol_offset = map_start_address;
- }
-
ElfW(Shdr) symtab, strtab;
// Consult a regular symbol table first.
symtab.sh_link * sizeof(symtab))) {
return false;
}
- if (FindSymbol(pc, fd, out, out_size, symbol_offset,
- &strtab, &symtab)) {
+ if (FindSymbol(pc, fd, out, out_size, base_address, &strtab, &symtab)) {
return true; // Found the symbol in a regular symbol table.
}
}
symtab.sh_link * sizeof(symtab))) {
return false;
}
- if (FindSymbol(pc, fd, out, out_size, symbol_offset,
- &strtab, &symtab)) {
+ if (FindSymbol(pc, fd, out, out_size, base_address, &strtab, &symtab)) {
return true; // Found the symbol in a dynamic symbol table.
}
}
int out_file_name_size) {
int object_fd;
- // Open /proc/self/maps.
int maps_fd;
NO_INTR(maps_fd = open("/proc/self/maps", O_RDONLY));
FileDescriptor wrapped_maps_fd(maps_fd);
return -1;
}
+ int mem_fd;
+ NO_INTR(mem_fd = open("/proc/self/mem", O_RDONLY));
+ FileDescriptor wrapped_mem_fd(mem_fd);
+ if (wrapped_mem_fd.get() < 0) {
+ return -1;
+ }
+
// Iterate over maps and look for the map containing the pc. Then
// look into the symbol tables inside.
char buf[1024]; // Big enough for line of sane /proc/self/maps
}
++cursor; // Skip ' '.
- // Check start and end addresses.
- if (!(start_address <= pc && pc < end_address)) {
- continue; // We skip this map. PC isn't in this map.
- }
-
// Read flags. Skip flags until we encounter a space or eol.
const char * const flags_start = cursor;
while (cursor < eol && *cursor != ' ') {
return -1; // Malformed line.
}
+ // Determine the base address by reading ELF headers in process memory.
+ ElfW(Ehdr) ehdr;
+ // Skip non-readable maps.
+ if (flags_start[0] == 'r' &&
+ ReadFromOffsetExact(mem_fd, &ehdr, sizeof(ElfW(Ehdr)), start_address) &&
+ memcmp(ehdr.e_ident, ELFMAG, SELFMAG) == 0) {
+ switch (ehdr.e_type) {
+ case ET_EXEC:
+ base_address = 0;
+ break;
+ case ET_DYN:
+ // Find the segment containing file offset 0. This will correspond
+ // to the ELF header that we just read. Normally this will have
+ // virtual address 0, but this is not guaranteed. We must subtract
+ // the virtual address from the address where the ELF header was
+ // mapped to get the base address.
+ //
+ // If we fail to find a segment for file offset 0, use the address
+ // of the ELF header as the base address.
+ base_address = start_address;
+ for (unsigned i = 0; i != ehdr.e_phnum; ++i) {
+ ElfW(Phdr) phdr;
+ if (ReadFromOffsetExact(
+ mem_fd, &phdr, sizeof(phdr),
+ start_address + ehdr.e_phoff + i * sizeof(phdr)) &&
+ phdr.p_type == PT_LOAD && phdr.p_offset == 0) {
+ base_address = start_address - phdr.p_vaddr;
+ break;
+ }
+ }
+ break;
+ default:
+ // ET_REL or ET_CORE. These aren't directly executable, so they don't
+ // affect the base address.
+ break;
+ }
+ }
+
+ // Check start and end addresses.
+ if (!(start_address <= pc && pc < end_address)) {
+ continue; // We skip this map. PC isn't in this map.
+ }
+
// Check flags. We are only interested in "r*x" maps.
if (flags_start[0] != 'r' || flags_start[2] != 'x') {
continue; // We skip this map.
}
++cursor; // Skip ' '.
- // Don't subtract 'start_address' from the first entry:
- // * If a binary is compiled w/o -pie, then the first entry in
- // process maps is likely the binary itself (all dynamic libs
- // are mapped higher in address space). For such a binary,
- // instruction offset in binary coincides with the actual
- // instruction address in virtual memory (as code section
- // is mapped to a fixed memory range).
- // * If a binary is compiled with -pie, all the modules are
- // mapped high at address space (in particular, higher than
- // shadow memory of the tool), so the module can't be the
- // first entry.
- base_address = ((num_maps == 1) ? 0U : start_address) - file_offset;
-
// Skip to file name. "cursor" now points to dev. We need to
// skip at least two spaces for dev and inode.
int num_spaces = 0;
}
}
if (!GetSymbolFromObjectFile(wrapped_object_fd.get(), pc0,
- out, out_size, start_address)) {
+ out, out_size, base_address)) {
return false;
}
_END_GOOGLE_NAMESPACE_
+#elif defined(OS_WINDOWS)
+
+#include <DbgHelp.h>
+#pragma comment(lib, "DbgHelp")
+
+_START_GOOGLE_NAMESPACE_
+
+class SymInitializer {
+public:
+ HANDLE process = NULL;
+ bool ready = false;
+ SymInitializer() {
+ // Initialize the symbol handler.
+ // https://msdn.microsoft.com/en-us/library/windows/desktop/ms680344(v=vs.85).aspx
+ process = GetCurrentProcess();
+ // Defer symbol loading.
+ // We do not request undecorated symbols with SYMOPT_UNDNAME
+ // because the mangling library calls UnDecorateSymbolName.
+ SymSetOptions(SYMOPT_DEFERRED_LOADS);
+ if (SymInitialize(process, NULL, true)) {
+ ready = true;
+ }
+ }
+ ~SymInitializer() {
+ SymCleanup(process);
+ // We do not need to close `HANDLE process` because it's a "pseudo handle."
+ }
+private:
+ SymInitializer(const SymInitializer&);
+ SymInitializer& operator=(const SymInitializer&);
+};
+
+static ATTRIBUTE_NOINLINE bool SymbolizeAndDemangle(void *pc, char *out,
+ int out_size) {
+ const static SymInitializer symInitializer;
+ if (!symInitializer.ready) {
+ return false;
+ }
+ // Resolve symbol information from address.
+ // https://msdn.microsoft.com/en-us/library/windows/desktop/ms680578(v=vs.85).aspx
+ char buf[sizeof(SYMBOL_INFO) + MAX_SYM_NAME];
+ SYMBOL_INFO *symbol = reinterpret_cast<SYMBOL_INFO *>(buf);
+ symbol->SizeOfStruct = sizeof(SYMBOL_INFO);
+ symbol->MaxNameLen = MAX_SYM_NAME;
+ // We use the ANSI version to ensure the string type is always `char *`.
+ // This could break if a symbol has Unicode in it.
+ BOOL ret = SymFromAddr(symInitializer.process,
+ reinterpret_cast<DWORD64>(pc), 0, symbol);
+ if (ret == 1 && static_cast<int>(symbol->NameLen) < out_size) {
+ // `NameLen` does not include the null terminating character.
+ strncpy(out, symbol->Name, static_cast<size_t>(symbol->NameLen) + 1);
+ out[static_cast<size_t>(symbol->NameLen)] = '\0';
+ // Symbolization succeeded. Now we try to demangle the symbol.
+ DemangleInplace(out, out_size);
+ return true;
+ }
+ return false;
+}
+
+_END_GOOGLE_NAMESPACE_
+
#else
# error BUG: HAVE_SYMBOLIZE was wrongly set
#endif
projects / platform / upstream / glog.git / blobdiff