[Lldb-commits] [lldb] r299612 - Some old mach-o core files have an LC_IDENT load command
Jason Molenda via lldb-commits
lldb-commits at lists.llvm.org
Wed Apr 5 18:50:12 PDT 2017
Author: jmolenda
Date: Wed Apr 5 20:50:11 2017
New Revision: 299612
URL: http://llvm.org/viewvc/llvm-project?rev=299612&view=rev
Log:
Some old mach-o core files have an LC_IDENT load command
and there's a string in there that can be helpful in locating
the kernel binary. Use it.
<rdar://problem/31444711>
Modified:
lldb/trunk/include/lldb/Symbol/ObjectFile.h
lldb/trunk/source/Plugins/ObjectFile/Mach-O/ObjectFileMachO.cpp
lldb/trunk/source/Plugins/ObjectFile/Mach-O/ObjectFileMachO.h
lldb/trunk/source/Plugins/Process/mach-core/ProcessMachCore.cpp
Modified: lldb/trunk/include/lldb/Symbol/ObjectFile.h
URL: http://llvm.org/viewvc/llvm-project/lldb/trunk/include/lldb/Symbol/ObjectFile.h?rev=299612&r1=299611&r2=299612&view=diff
==============================================================================
--- lldb/trunk/include/lldb/Symbol/ObjectFile.h (original)
+++ lldb/trunk/include/lldb/Symbol/ObjectFile.h Wed Apr 5 20:50:11 2017
@@ -563,6 +563,19 @@ public:
virtual uint32_t GetNumThreadContexts() { return 0; }
+ //------------------------------------------------------------------
+ /// Some object files may have an identifier string embedded in them,
+ /// e.g. in a Mach-O core file using the LC_IDENT load command (which
+ /// is obsolete, but can still be found in some old files)
+ ///
+ /// @return
+ /// Returns the identifier string if one exists, else an empty
+ /// string.
+ //------------------------------------------------------------------
+ virtual std::string GetIdentifierString () {
+ return std::string();
+ }
+
virtual lldb::RegisterContextSP
GetThreadContextAtIndex(uint32_t idx, lldb_private::Thread &thread) {
return lldb::RegisterContextSP();
Modified: lldb/trunk/source/Plugins/ObjectFile/Mach-O/ObjectFileMachO.cpp
URL: http://llvm.org/viewvc/llvm-project/lldb/trunk/source/Plugins/ObjectFile/Mach-O/ObjectFileMachO.cpp?rev=299612&r1=299611&r2=299612&view=diff
==============================================================================
--- lldb/trunk/source/Plugins/ObjectFile/Mach-O/ObjectFileMachO.cpp (original)
+++ lldb/trunk/source/Plugins/ObjectFile/Mach-O/ObjectFileMachO.cpp Wed Apr 5 20:50:11 2017
@@ -5353,6 +5353,37 @@ uint32_t ObjectFileMachO::GetNumThreadCo
return m_thread_context_offsets.GetSize();
}
+// The LC_IDENT load command has been obsoleted for a very
+// long time and it should not occur in Mach-O files. But
+// if it is there, it may contain a hint about where to find
+// the main binary in a core file, so we'll use it.
+std::string ObjectFileMachO::GetIdentifierString() {
+ std::string result;
+ ModuleSP module_sp(GetModule());
+ if (module_sp) {
+ std::lock_guard<std::recursive_mutex> guard(module_sp->GetMutex());
+ lldb::offset_t offset = MachHeaderSizeFromMagic(m_header.magic);
+ for (uint32_t i = 0; i < m_header.ncmds; ++i) {
+ const uint32_t cmd_offset = offset;
+ struct ident_command ident_command;
+ if (m_data.GetU32(&offset, &ident_command, 2) == NULL)
+ break;
+ if (ident_command.cmd == LC_IDENT && ident_command.cmdsize != 0) {
+ char *buf = (char *)malloc (ident_command.cmdsize);
+ if (buf != nullptr
+ && m_data.CopyData (offset, ident_command.cmdsize, buf) == ident_command.cmdsize) {
+ buf[ident_command.cmdsize - 1] = '\0';
+ result = buf;
+ }
+ if (buf)
+ free (buf);
+ }
+ offset = cmd_offset + ident_command.cmdsize;
+ }
+ }
+ return result;
+}
+
lldb::RegisterContextSP
ObjectFileMachO::GetThreadContextAtIndex(uint32_t idx,
lldb_private::Thread &thread) {
Modified: lldb/trunk/source/Plugins/ObjectFile/Mach-O/ObjectFileMachO.h
URL: http://llvm.org/viewvc/llvm-project/lldb/trunk/source/Plugins/ObjectFile/Mach-O/ObjectFileMachO.h?rev=299612&r1=299611&r2=299612&view=diff
==============================================================================
--- lldb/trunk/source/Plugins/ObjectFile/Mach-O/ObjectFileMachO.h (original)
+++ lldb/trunk/source/Plugins/ObjectFile/Mach-O/ObjectFileMachO.h Wed Apr 5 20:50:11 2017
@@ -111,6 +111,8 @@ public:
uint32_t GetNumThreadContexts() override;
+ std::string GetIdentifierString() override;
+
lldb::RegisterContextSP
GetThreadContextAtIndex(uint32_t idx, lldb_private::Thread &thread) override;
Modified: lldb/trunk/source/Plugins/Process/mach-core/ProcessMachCore.cpp
URL: http://llvm.org/viewvc/llvm-project/lldb/trunk/source/Plugins/Process/mach-core/ProcessMachCore.cpp?rev=299612&r1=299611&r2=299612&view=diff
==============================================================================
--- lldb/trunk/source/Plugins/Process/mach-core/ProcessMachCore.cpp (original)
+++ lldb/trunk/source/Plugins/Process/mach-core/ProcessMachCore.cpp Wed Apr 5 20:50:11 2017
@@ -291,8 +291,42 @@ Error ProcessMachCore::DoLoadCore() {
m_core_range_infos.Sort();
}
- if (m_dyld_addr == LLDB_INVALID_ADDRESS ||
- m_mach_kernel_addr == LLDB_INVALID_ADDRESS) {
+
+ bool found_main_binary_definitively = false;
+
+ // This checks for the presence of an LC_IDENT string in a core file;
+ // LC_IDENT is very obsolete and should not be used in new code, but
+ // if the load command is present, let's use the contents.
+ std::string corefile_identifier = core_objfile->GetIdentifierString();
+ if (corefile_identifier.find("Darwin Kernel") != std::string::npos) {
+ UUID uuid;
+ addr_t addr = LLDB_INVALID_ADDRESS;
+ if (corefile_identifier.find("UUID=") != std::string::npos) {
+ size_t p = corefile_identifier.find("UUID=") + strlen("UUID=");
+ std::string uuid_str = corefile_identifier.substr(p, 36);
+ uuid.SetFromCString(uuid_str.c_str());
+ }
+ if (corefile_identifier.find("stext=") != std::string::npos) {
+ size_t p = corefile_identifier.find("stext=") + strlen("stext=");
+ if (corefile_identifier[p] == '0' && corefile_identifier[p + 1] == 'x') {
+ errno = 0;
+ addr = ::strtoul(corefile_identifier.c_str() + p, NULL, 16);
+ if (errno != 0 || addr == 0)
+ addr = LLDB_INVALID_ADDRESS;
+ }
+ }
+ if (uuid.IsValid() && addr != LLDB_INVALID_ADDRESS) {
+ m_mach_kernel_addr = addr;
+ found_main_binary_definitively = true;
+ if (log)
+ log->Printf("ProcessMachCore::DoLoadCore: Using the kernel address 0x%" PRIx64
+ "from LC_IDENT string '%s'", addr, corefile_identifier.c_str());
+ }
+ }
+
+ if (found_main_binary_definitively == false &&
+ (m_dyld_addr == LLDB_INVALID_ADDRESS ||
+ m_mach_kernel_addr == LLDB_INVALID_ADDRESS)) {
// We need to locate the main executable in the memory ranges
// we have in the core file. We need to search for both a user-process dyld
// binary
@@ -317,7 +351,8 @@ Error ProcessMachCore::DoLoadCore() {
}
}
- if (m_mach_kernel_addr != LLDB_INVALID_ADDRESS) {
+ if (found_main_binary_definitively == false
+ && m_mach_kernel_addr != LLDB_INVALID_ADDRESS) {
// In the case of multiple kernel images found in the core file via
// exhaustive
// search, we may not pick the correct one. See if the
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