[Lldb-commits] [lldb] [LLDB][Minidump]Update MinidumpFileBuilder to read and write in chunks (PR #129307)

[Greg Clayton via lldb-commits]

================
@@ -969,6 +969,66 @@ Status MinidumpFileBuilder::DumpDirectories() const {
   return error;
 }
 
+Status MinidumpFileBuilder::ReadWriteMemoryInChunks(
+    lldb_private::DataBufferHeap &data_buffer,
+    const lldb_private::CoreFileMemoryRange &range, uint64_t &bytes_read) {
+
+  const lldb::addr_t addr = range.range.start();
+  const lldb::addr_t size = range.range.size();
+  Log *log = GetLog(LLDBLog::Object);
+  Status addDataError;
+  Process::ReadMemoryChunkCallback callback =
+      [&](Status &error, lldb::addr_t current_addr, const void *buf,
+          uint64_t bytes_read_for_chunk) -> lldb_private::IterationAction {
+    if (error.Fail() || bytes_read_for_chunk == 0) {
+      LLDB_LOGF(log,
+                "Failed to read memory region at: %" PRIx64
+                ". Bytes read: %zu, error: %s",
+                current_addr, bytes_read_for_chunk, error.AsCString());
+
+      // If we failed in a memory read, we would normally want to skip
+      // this entire region, if we had already written to the minidump
+      // file, we can't easily rewind that state.
+      //
+      // So if we do encounter an error while reading, we just return
+      // immediately, any prior bytes read will still be included but
+      // any bytes partially read before the error are ignored.
+      return lldb_private::IterationAction::Stop;
+    }
+
+    // Write to the minidump file with the chunk potentially flushing to
+    // disk.
+    // This error will be captured by the outer scope and is considered fatal.
+    // If we get an error writing to disk we can't easily guarauntee that we
+    // won't corrupt the minidump.
+    addDataError = AddData(buf, bytes_read_for_chunk);
+    if (addDataError.Fail())
+      return lldb_private::IterationAction::Stop;
+
+    // If we have a partial read, report it, but only if the partial read
+    // didn't finish reading the entire region.
+    if (bytes_read_for_chunk != data_buffer.GetByteSize() &&
+        current_addr + bytes_read_for_chunk != size) {
+      LLDB_LOGF(log,
+                "Memory region at: %" PRIx64 " partiall read %" PRIx64
----------------
clayborg wrote:

s/partiall/partial/

You also want all addresses to be prefixed with 0x here, so the format string should be:
```
"Memory region at: 0x%" PRIx64 " partiall read 0x%" PRIx64
```
Same for format string below.

https://github.com/llvm/llvm-project/pull/129307