[PATCH v5 05/16] qemu-iotests: add option to attach gdbserver

[Emanuele Giuseppe Esposito <eesposit@redhat.com>]

Define --gdb flag and GDB_OPTIONS environment variable
to python tests to attach a gdbserver to each qemu instance.
This patch only adds and parses this flag, it does not yet add
the implementation for it.

if --gdb is not provided but $GDB_OPTIONS is set, ignore the
environment variable.

Signed-off-by: Emanuele Giuseppe Esposito <eesposit@redhat.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
---
 tests/qemu-iotests/check      |  6 +++++-
 tests/qemu-iotests/iotests.py |  5 +++++
 tests/qemu-iotests/testenv.py | 17 +++++++++++++++--
 3 files changed, 25 insertions(+), 3 deletions(-)

diff --git a/tests/qemu-iotests/check b/tests/qemu-iotests/check
index 3f3962dd75..1dba4218c0 100755
--- a/tests/qemu-iotests/check
+++ b/tests/qemu-iotests/check
@@ -36,6 +36,9 @@ def make_argparser() -> argparse.ArgumentParser:
                    help='pretty print output for make check')
 
     p.add_argument('-d', dest='debug', action='store_true', help='debug')
+    p.add_argument('--gdb', action='store_true',
+                   help="start gdbserver with $GDB_OPTIONS options \
+                        ('localhost:12345' if $GDB_OPTIONS is empty)")
     p.add_argument('--misalign', action='store_true',
                    help='misalign memory allocations')
     p.add_argument('--color', choices=['on', 'off', 'auto'],
@@ -114,7 +117,8 @@ if __name__ == '__main__':
     env = TestEnv(imgfmt=args.imgfmt, imgproto=args.imgproto,
                   aiomode=args.aiomode, cachemode=args.cachemode,
                   imgopts=args.imgopts, misalign=args.misalign,
-                  debug=args.debug, valgrind=args.valgrind)
+                  debug=args.debug, valgrind=args.valgrind,
+                  gdb=args.gdb)
 
     if len(sys.argv) > 1 and sys.argv[-len(args.tests)-1] == '--':
         if not args.tests:
diff --git a/tests/qemu-iotests/iotests.py b/tests/qemu-iotests/iotests.py
index 6b0db4ce54..c86f239d81 100644
--- a/tests/qemu-iotests/iotests.py
+++ b/tests/qemu-iotests/iotests.py
@@ -74,6 +74,11 @@
 qemu_prog = os.environ.get('QEMU_PROG', 'qemu')
 qemu_opts = os.environ.get('QEMU_OPTIONS', '').strip().split(' ')
 
+gdb_qemu_env = os.environ.get('GDB_OPTIONS')
+qemu_gdb = []
+if gdb_qemu_env:
+    qemu_gdb = ['gdbserver'] + gdb_qemu_env.strip().split(' ')
+
 imgfmt = os.environ.get('IMGFMT', 'raw')
 imgproto = os.environ.get('IMGPROTO', 'file')
 output_dir = os.environ.get('OUTPUT_DIR', '.')
diff --git a/tests/qemu-iotests/testenv.py b/tests/qemu-iotests/testenv.py
index 0c3fe75636..8501c6caf5 100644
--- a/tests/qemu-iotests/testenv.py
+++ b/tests/qemu-iotests/testenv.py
@@ -27,6 +27,7 @@
 import glob
 from typing import List, Dict, Any, Optional, ContextManager
 
+DEF_GDB_OPTIONS = 'localhost:12345'
 
 def isxfile(path: str) -> bool:
     return os.path.isfile(path) and os.access(path, os.X_OK)
@@ -72,7 +73,8 @@ class TestEnv(ContextManager['TestEnv']):
                      'QEMU_NBD_OPTIONS', 'IMGOPTS', 'IMGFMT', 'IMGPROTO',
                      'AIOMODE', 'CACHEMODE', 'VALGRIND_QEMU',
                      'CACHEMODE_IS_DEFAULT', 'IMGFMT_GENERIC', 'IMGOPTSSYNTAX',
-                     'IMGKEYSECRET', 'QEMU_DEFAULT_MACHINE', 'MALLOC_PERTURB_']
+                     'IMGKEYSECRET', 'QEMU_DEFAULT_MACHINE', 'MALLOC_PERTURB_',
+                     'GDB_OPTIONS']
 
     def prepare_subprocess(self, args: List[str]) -> Dict[str, str]:
         if self.debug:
@@ -178,7 +180,8 @@ def __init__(self, imgfmt: str, imgproto: str, aiomode: str,
                  imgopts: Optional[str] = None,
                  misalign: bool = False,
                  debug: bool = False,
-                 valgrind: bool = False) -> None:
+                 valgrind: bool = False,
+                 gdb: bool = False) -> None:
         self.imgfmt = imgfmt
         self.imgproto = imgproto
         self.aiomode = aiomode
@@ -186,6 +189,15 @@ def __init__(self, imgfmt: str, imgproto: str, aiomode: str,
         self.misalign = misalign
         self.debug = debug
 
+        if gdb:
+            self.gdb_options = os.getenv('GDB_OPTIONS', DEF_GDB_OPTIONS)
+            if not self.gdb_options:
+                # cover the case 'export GDB_OPTIONS='
+                self.gdb_options = DEF_GDB_OPTIONS
+        elif 'GDB_OPTIONS' in os.environ:
+            # to not propagate it in prepare_subprocess()
+            del os.environ['GDB_OPTIONS']
+
         if valgrind:
             self.valgrind_qemu = 'y'
 
@@ -285,6 +297,7 @@ def print_env(self) -> None:
 TEST_DIR      -- {TEST_DIR}
 SOCK_DIR      -- {SOCK_DIR}
 SOCKET_SCM_HELPER -- {SOCKET_SCM_HELPER}
+GDB_OPTIONS   -- {GDB_OPTIONS}
 """
 
         args = collections.defaultdict(str, self.get_env())
-- 
2.30.2