[lldb] [gdb-server] Implement the vFile:fstat packet

Differential Revision: https://reviews.llvm.org/D107840

1 files changed, 43 insertions, 0 deletions

diff --git a/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationServerCommon.cpp b/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationServerCommon.cpp
index 9627fb1..21700f5 100644
--- a/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationServerCommon.cpp
+++ b/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationServerCommon.cpp
@@ -157,6 +157,9 @@ GDBRemoteCommunicationServerCommon::GDBRemoteCommunicationServerCommon(
       StringExtractorGDBRemote::eServerPacketType_vFile_size,
       &GDBRemoteCommunicationServerCommon::Handle_vFile_Size);
   RegisterMemberFunctionHandler(
+      StringExtractorGDBRemote::eServerPacketType_vFile_fstat,
+      &GDBRemoteCommunicationServerCommon::Handle_vFile_FStat);
+  RegisterMemberFunctionHandler(
       StringExtractorGDBRemote::eServerPacketType_vFile_stat,
       &GDBRemoteCommunicationServerCommon::Handle_vFile_Stat);
   RegisterMemberFunctionHandler(
@@ -754,6 +757,46 @@ GDBRemoteCommunicationServerCommon::Handle_qPlatform_shell(
   return SendErrorResponse(24);
 }
 
+template <typename T, typename U>
+static void fill_clamp(T &dest, U src, typename T::value_type fallback) {
+  dest = src <= std::numeric_limits<typename T::value_type>::max() ? src
+                                                                   : fallback;
+}
+
+GDBRemoteCommunication::PacketResult
+GDBRemoteCommunicationServerCommon::Handle_vFile_FStat(
+    StringExtractorGDBRemote &packet) {
+  StreamGDBRemote response;
+  packet.SetFilePos(::strlen("vFile:fstat:"));
+  int fd = packet.GetS32(-1, 16);
+
+  struct stat file_stats;
+  if (::fstat(fd, &file_stats) == -1) {
+    const int save_errno = errno;
+    response.Printf("F-1,%x", save_errno);
+    return SendPacketNoLock(response.GetString());
+  }
+
+  GDBRemoteFStatData data;
+  fill_clamp(data.gdb_st_dev, file_stats.st_dev, 0);
+  fill_clamp(data.gdb_st_ino, file_stats.st_ino, 0);
+  data.gdb_st_mode = file_stats.st_mode;
+  fill_clamp(data.gdb_st_nlink, file_stats.st_nlink, UINT32_MAX);
+  fill_clamp(data.gdb_st_uid, file_stats.st_uid, 0);
+  fill_clamp(data.gdb_st_gid, file_stats.st_gid, 0);
+  fill_clamp(data.gdb_st_rdev, file_stats.st_rdev, 0);
+  data.gdb_st_size = file_stats.st_size;
+  data.gdb_st_blksize = file_stats.st_blksize;
+  data.gdb_st_blocks = file_stats.st_blocks;
+  fill_clamp(data.gdb_st_atime, file_stats.st_atime, 0);
+  fill_clamp(data.gdb_st_mtime, file_stats.st_mtime, 0);
+  fill_clamp(data.gdb_st_ctime, file_stats.st_ctime, 0);
+
+  response.Printf("F%zx;", sizeof(data));
+  response.PutEscapedBytes(&data, sizeof(data));
+  return SendPacketNoLock(response.GetString());
+}
+
 GDBRemoteCommunication::PacketResult
 GDBRemoteCommunicationServerCommon::Handle_vFile_Stat(
     StringExtractorGDBRemote &packet) {