From cfff4e343b6678a9a8ada6304b3856258bc1190a Mon Sep 17 00:00:00 2001
From: Nikita Putikhin <nputikhin@google.com>
Date: Mon, 22 Apr 2024 13:04:45 +0200
Subject: Add --cwd parameter to set debuggee working directory in lldbclient

Setting the working direcotry is useful for binaries that expect to be
run from a specific folder. In particular, this allows to debug target
integration tests with data files, since they expect these files to be
available by relative paths.

Test: lldbclient.py /data/ -r pwd # prints /
      lldbclient.py --cwd /data/ -r pwd # prints /data
      lldbclient.py --cwd /data/ --chroot / -r pwd # exits with error
      lldbclient.py --cwd /invalid_path -r pwd # exits with error
Change-Id: I9d1002c28219028d0120df3b9620e09030d1361e
---
 python-packages/gdbrunner/gdbrunner/__init__.py | 13 ++++++++++++-
 scripts/gdbclient.py                            | 19 +++++++++++++++++--
 2 files changed, 29 insertions(+), 3 deletions(-)

diff --git a/python-packages/gdbrunner/gdbrunner/__init__.py b/python-packages/gdbrunner/gdbrunner/__init__.py
index ebbe9e0b5..72e59800f 100644
--- a/python-packages/gdbrunner/gdbrunner/__init__.py
+++ b/python-packages/gdbrunner/gdbrunner/__init__.py
@@ -144,7 +144,7 @@ def get_pids(device, process_name):
 
 def start_gdbserver(device, gdbserver_local_path, gdbserver_remote_path,
                     target_pid, run_cmd, debug_socket, port, run_as_cmd=[],
-                    lldb=False, chroot=""):
+                    lldb=False, chroot="", cwd=""):
     """Start gdbserver in the background and forward necessary ports.
 
     Args:
@@ -156,6 +156,8 @@ def start_gdbserver(device, gdbserver_local_path, gdbserver_remote_path,
         debug_socket: Device path to place gdbserver unix domain socket.
         port: Host port to forward the debug_socket to.
         run_as_cmd: run-as or su command to prepend to commands.
+        chroot: The directory to pass to chroot when running the command. Cannot be set with cwd.
+        cwd: The working directory for the command. Cannot be set with chroot.
 
     Returns:
         Popen handle to the `adb shell` process gdbserver was started with.
@@ -164,6 +166,12 @@ def start_gdbserver(device, gdbserver_local_path, gdbserver_remote_path,
     assert target_pid is None or run_cmd is None
 
     if chroot:
+        # Chroot changes the working directory, so cd won't work if ran before chroot.
+        # On the other hand naively passing cd to chroot also won't work: chroot
+        # executes a binary, while cd is a bash command.
+        # They are unlikely to be used together anyway, so we simply disallow it.
+        if cwd:
+            raise ValueError('chroot and cwd cannot be set together')
         run_as_cmd = ["chroot", chroot] + run_as_cmd
 
     # Remove the old socket file.
@@ -209,6 +217,9 @@ def start_gdbserver(device, gdbserver_local_path, gdbserver_remote_path,
                                              "gdbclient.log")
         print("Redirecting gdbserver output to {}".format(gdbserver_output_path))
     gdbserver_output = open(gdbserver_output_path, 'w')
+
+    if cwd:
+        gdbserver_cmd = ["cd", cwd, "&&"] + gdbserver_cmd
     return device.shell_popen(gdbserver_cmd, stdout=gdbserver_output,
                               stderr=gdbserver_output)
 
diff --git a/scripts/gdbclient.py b/scripts/gdbclient.py
index f270c19ed..81d9992f5 100755
--- a/scripts/gdbclient.py
+++ b/scripts/gdbclient.py
@@ -123,7 +123,10 @@ def parse_args() -> argparse.Namespace:
         help="set environment variable when running a binary")
     parser.add_argument(
         "--chroot", nargs='?', default="", metavar="PATH",
-        help="run command in a chroot in the given directory")
+        help="run command in a chroot in the given directory. Cannot be used with --cwd.")
+    parser.add_argument(
+        "--cwd", nargs='?', default="", metavar="PATH",
+        help="working directory for the command. Cannot be used with --chroot.")
 
     return parser.parse_args()
 
@@ -136,6 +139,11 @@ def verify_device(device: adb.AndroidDevice) -> None:
         sys.exit(msg.format(target_device, ", ".join(n if n else "None" for n in names)))
 
 
+def get_device_dir_exists(device: adb.AndroidDevice, dir: str) -> bool:
+    exit_code, _, _ = device.shell_nocheck(['[', '-d', dir, ']'])
+    return exit_code == 0
+
+
 def get_remote_pid(device: adb.AndroidDevice, process_name: str) -> int:
     processes = gdbrunner.get_processes(device)
     if process_name not in processes:
@@ -458,6 +466,13 @@ def do_main() -> None:
     root = os.environ["ANDROID_BUILD_TOP"]
     sysroot = os.path.join(os.environ["ANDROID_PRODUCT_OUT"], "symbols")
 
+    if args.cwd:
+        if not get_device_dir_exists(device, args.cwd):
+            raise ValueError('Working directory does not exist on device: {}'.format(args.cwd))
+        if args.chroot:
+            # See the comment in start_gdbserver about why this is not implemented.
+            raise ValueError('--cwd and --chroot cannot be used together')
+
     # Make sure the environment matches the attached device.
     # Skip when running in a chroot because the chroot lunch target may not
     # match the device's lunch target.
@@ -517,7 +532,7 @@ def do_main() -> None:
             gdbrunner.start_gdbserver(
                 device, server_local_path, server_remote_path,
                 target_pid=pid, run_cmd=run_cmd, debug_socket=debug_socket,
-                port=args.port, run_as_cmd=cmd_prefix, lldb=True, chroot=args.chroot)
+                port=args.port, run_as_cmd=cmd_prefix, lldb=True, chroot=args.chroot, cwd=args.cwd)
         else:
             print(
                 "Connecting to tracing pid {} using local port {}".format(
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