Author: mgorny Date: Tue Apr 30 09:30:32 2019 New Revision: 359572 URL: http://llvm.org/viewvc/llvm-project?rev=359572&view=rev Log: [lldb] [Process/NetBSD] Fix handling piod_len from PT_IO calls
Fix bugs in piod_len return value processing in ReadMemory() and WriteMemory() methods. In particular, add support for piod_len == 0 indicating EOF, and fix summing bytes_read/bytes_written when PT_IO does partial reads/writes. The EOF condition could happen if LLDB attempts to read past vm.maxaddress, e.g. as a result of RBP containing large (invalid) value. Previously, the 0 return caused the function to retry reading via PT_IO indefinitely, effectively deadlooping lldb-server. Partial reads probably did not occur in practice, yet they would cause ReadMemory() to return incorrect bytes_read and/or overwrite previously read data. WriteMemory() suffered from analoguous problems. Differential Revision: https://reviews.llvm.org/D61310 Modified: lldb/trunk/source/Plugins/Process/NetBSD/NativeProcessNetBSD.cpp Modified: lldb/trunk/source/Plugins/Process/NetBSD/NativeProcessNetBSD.cpp URL: http://llvm.org/viewvc/llvm-project/lldb/trunk/source/Plugins/Process/NetBSD/NativeProcessNetBSD.cpp?rev=359572&r1=359571&r2=359572&view=diff ============================================================================== --- lldb/trunk/source/Plugins/Process/NetBSD/NativeProcessNetBSD.cpp (original) +++ lldb/trunk/source/Plugins/Process/NetBSD/NativeProcessNetBSD.cpp Tue Apr 30 09:30:32 2019 @@ -695,10 +695,10 @@ Status NativeProcessNetBSD::ReadMemory(l io.piod_addr = dst + bytes_read; Status error = NativeProcessNetBSD::PtraceWrapper(PT_IO, GetID(), &io); - if (error.Fail()) + if (error.Fail() || io.piod_len == 0) return error; - bytes_read = io.piod_len; + bytes_read += io.piod_len; io.piod_len = size - bytes_read; } while (bytes_read < size); @@ -723,10 +723,10 @@ Status NativeProcessNetBSD::WriteMemory( io.piod_offs = (void *)(addr + bytes_written); Status error = NativeProcessNetBSD::PtraceWrapper(PT_IO, GetID(), &io); - if (error.Fail()) + if (error.Fail() || io.piod_len == 0) return error; - bytes_written = io.piod_len; + bytes_written += io.piod_len; io.piod_len = size - bytes_written; } while (bytes_written < size); _______________________________________________ lldb-commits mailing list lldb-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/lldb-commits
