derek/gem5
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

sim: Add serialization for file descriptor array

Browse Source 
Add serialization of the fd array when checkpointing in SE mode.
With this patch, host backed files are restored.
Further work needs to be done for restoring other types of
file descriptor.

As the file path saved is relative, on restoration of the checkpoint,
it may fail to open the file if the path is no longer valid.
If it cannot open the file, it will exit the simulation
with a meaningful error message.

Change-Id: I4d0c7cd614a8abaffcae9aba1a28c9fdbc023c5a
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/46619
Reviewed-by: Jason Lowe-Power <power.jg@gmail.com>
Maintainer: Jason Lowe-Power <power.jg@gmail.com>
Tested-by: kokoro <noreply+kokoro@google.com>
This commit is contained in:
Tom Rollet
2021-06-08 14:55:48 +02:00
parent b9d35c7edc
commit 835607d497
6 changed files with 133 additions and 19 deletions
Download Patch File Download Diff File Expand all files Collapse all files

83
src/sim/fd_array.cc
View File

@@ -298,7 +298,7 @@ FDArray::openFile(std::string const& filename, int flags, mode_t mode) const
int sim_fd = open(filename.c_str(), flags, mode);
if (sim_fd != -1)
return sim_fd;
fatal("Unable to open %s with mode %O", filename, mode);
fatal("Unable to open %s with mode %d", filename, mode);
}
int
@@ -348,3 +348,84 @@ FDArray::closeFDEntry(int tgt_fd)
return status;
}
void
FDArray::serialize(CheckpointOut &cp) const {
ScopedCheckpointSection sec(cp, "fdarray");
paramOut(cp, "size", _fdArray.size());
for (int tgt_fd = 0; tgt_fd < _fdArray.size(); tgt_fd++) {
auto fd = _fdArray[tgt_fd];
ScopedCheckpointSection sec(cp, csprintf("Entry%d", tgt_fd));
if (!fd) {
paramOut(cp, "class", FDEntry::FDClass::fd_null);
continue;
}
paramOut(cp, "class", fd->getClass());
fd->serialize(cp);
}
}
void
FDArray::unserialize(CheckpointIn &cp) {
ScopedCheckpointSection sec(cp, "fdarray");
uint64_t size;
paramIn(cp, "size", size);
assert(_fdArray.size() == size &&
"FDArray sizes do not match at unserialize!");
for (int tgt_fd = 0; tgt_fd < _fdArray.size(); tgt_fd++) {
if (tgt_fd == STDIN_FILENO || tgt_fd == STDOUT_FILENO ||
tgt_fd == STDERR_FILENO)
continue;
ScopedCheckpointSection sec(cp, csprintf("Entry%d", tgt_fd));
FDEntry::FDClass fd_class;
paramIn(cp, "class", fd_class);
std::shared_ptr<FDEntry> fdep;
switch (fd_class) {
case FDEntry::FDClass::fd_base:
panic("Abstract fd entry was serialized");
break;
case FDEntry::FDClass::fd_hb:
fdep = std::make_shared<HBFDEntry>(0, 0);
break;
case FDEntry::FDClass::fd_file:
fdep = std::make_shared<FileFDEntry>(0, 0, "", 0, 00);
break;
case FDEntry::FDClass::fd_device:
fdep = std::make_shared<DeviceFDEntry>(nullptr, "");
break;
case FDEntry::FDClass::fd_pipe:
fdep = std::make_shared<PipeFDEntry>(
0, 0, PipeFDEntry::EndType::read);
break;
case FDEntry::FDClass::fd_socket:
fdep = std::make_shared<SocketFDEntry>(0, 0, 0, 0);
break;
case FDEntry::FDClass::fd_null:
continue;
default:
panic("Unrecognized fd class");
break;
}
fdep->unserialize(cp);
auto this_ffd = std::dynamic_pointer_cast<FileFDEntry>(fdep);
if (!this_ffd)
continue;
setFDEntry(tgt_fd, fdep);
mode_t mode = this_ffd->getFileMode();
std::string const& path = this_ffd->getFileName();
int flags = this_ffd->getFlags();
// Re-open the file and assign a new sim_fd
int sim_fd = openFile(path, flags, mode);
this_ffd->setSimFD(sim_fd);
// Restore the file offset to the proper value
uint64_t file_offset = this_ffd->getFileOffset();
lseek(sim_fd, file_offset, SEEK_SET);
}
}