1 files changed, 109 insertions, 0 deletions
diff --git a/tools/guest-diag/qga_fetch.py b/tools/guest-diag/qga_fetch.py
new file mode 100755
index 0000000..2fd53fc
--- /dev/null
+++ b/tools/guest-diag/qga_fetch.py
@@ -0,0 +1,109 @@
+#!/usr/bin/env python3
+# Fetch a file from the guest via the QEMU guest agent protocol
+# (/tmp/qemu-guest-agent.sock, the virtio-serial QGA chardev - the same
+# socket vgpu_vm.py exec uses). Usage: qga_fetch.py <guest_path> <host_path> [chunk]
+#
+# Robustness (r1490): the r1489 evidence capture fetched nothing because the
+# guest-side frame was still being written / the agent answered late. Retry
+# the open a few times, tolerate error replies with a clear diagnostic, use a
+# long socket timeout, and write to a temporary file so a partial transfer is
+# never mistaken for a complete capture.
+import base64
+import json
+import os
+import socket
+import sys
+import time
+
+if len(sys.argv) < 3:
+    print("usage: qga_fetch.py <guest_path> <host_path> [chunk]", file=sys.stderr)
+    sys.exit(2)
+
+GUEST = sys.argv[1]
+HOST = sys.argv[2]
+CHUNK = int(sys.argv[3]) if len(sys.argv) > 3 else 1 << 20
+SOCK = "/tmp/qemu-guest-agent.sock"
+TRIES = 6
+TMP = HOST + ".part"
+
+
+def recv_line(s):
+    buf = b""
+    while b"\n" not in buf:
+        chunk = s.recv(65536)
+        if not chunk:
+            break
+        buf += chunk
+    return buf.split(b"\n", 1)[0]
+
+
+def cmd(s, obj):
+    s.sendall((json.dumps(obj) + "\r\n").encode())
+    line = recv_line(s)
+    return json.loads(line)
+
+
+def open_guest():
+    last = None
+    for i in range(TRIES):
+        try:
+            s = socket.socket(socket.AF_UNIX, socket.SOCK_STREAM)
+            s.settimeout(120.0)
+            s.connect(SOCK)
+            r = cmd(s, {"execute": "guest-file-open",
+                        "arguments": {"path": GUEST, "mode": "r"}})
+            if "return" in r:
+                return s, r["return"], None
+            last = f"guest-file-open error: {r.get('error')}"
+        except Exception as e:  # noqa: BLE001 - diagnostic surface
+            last = f"guest-file-open exception: {e}"
+        try:
+            s.close()
+        except Exception:
+            pass
+        time.sleep(1.5)
+        if i + 1 < TRIES:
+            print(f"retry {i + 1}/{TRIES}: {last}", file=sys.stderr)
+    return None, None, last
+
+
+s, h, err = open_guest()
+if s is None:
+    print(f"FETCH-FAIL {GUEST} -> {HOST}: {err}", file=sys.stderr)
+    sys.exit(1)
+
+print(f"handle={h}")
+total = 0
+try:
+    with open(TMP, "wb") as out:
+        while True:
+            r = cmd(s, {"execute": "guest-file-read",
+                        "arguments": {"handle": h, "count": CHUNK}})
+            if "return" not in r:
+                raise RuntimeError(f"guest-file-read error: {r.get('error')}")
+            d = r["return"]
+            buf = base64.b64decode(d.get("buf-b64", ""))
+            if buf:
+                out.write(buf)
+                total += len(buf)
+                print(f"\r{total}", end="", flush=True)
+            if d.get("eof"):
+                break
+    cmd(s, {"execute": "guest-file-close", "arguments": {"handle": h}})
+except Exception as e:  # noqa: BLE001
+    print(f"\nFETCH-FAIL {GUEST} -> {HOST}: {e}", file=sys.stderr)
+    try:
+        if os.path.exists(TMP):
+            os.unlink(TMP)
+    except OSError:
+        pass
+    sys.exit(1)
+finally:
+    try:
+        s.close()
+    except Exception:
+        pass
+
+os.replace(TMP, HOST)
+print(f"\nFETCHED {total} bytes -> {HOST}")
+sys.exit(0)