[Lldb-commits] [lldb] 45aa435 - [lldb/qemu] Separate host and target environments
Pavel Labath via lldb-commits
lldb-commits at lists.llvm.org
Wed Dec 8 04:08:36 PST 2021
Author: Pavel Labath
Date: 2021-12-08T13:08:19+01:00
New Revision: 45aa435661d80843554d425156f300b207d8a0a0
URL: https://github.com/llvm/llvm-project/commit/45aa435661d80843554d425156f300b207d8a0a0
DIFF: https://github.com/llvm/llvm-project/commit/45aa435661d80843554d425156f300b207d8a0a0.diff
LOG: [lldb/qemu] Separate host and target environments
Qemu normally forwards its (host) environment variables to the emulated
process. While this works fine for most variables, there are some (few, but
fairly important) variables where this is not possible. LD_LIBRARY_PATH
is the probably the most important of those -- we don't want the library
search path for the emulated libraries to interfere with the libraries
that the emulator itself needs.
For this reason, qemu provides a mechanism (QEMU_SET_ENV,
QEMU_UNSET_ENV) to set variables only for the emulated process. This
patch makes use of that functionality to pass any user-provided
variables to the emulated process. Since we're piggy-backing on the
normal lldb environment-handling mechanism, all the usual mechanism to
provide environment (target.env-vars setting, SBLaunchInfo, etc.) work
out-of-the-box, and the only thing we need to do is to properly
construct the qemu environment variables.
This patch also adds a new setting -- target-env-vars, which represents
environment variables which are added (on top of the host environment)
to the default launch environments of all (qemu) targets. The reason for
its existence is to enable the configuration (e.g., from a startup
script) of the default launch environment, before any target is created.
The idea is that this would contain the variables (like the
aforementioned LD_LIBRARY_PATH) common to all targets being debugged on
the given system. The user is, of course, free to customize the
environment for a particular target in the usual manner.
The reason I do not want to use/recommend the "global" version of the
target.env-vars setting for this purpose is that the setting would apply
to all targets, whereas the settings (their values) I have mentioned
would be specific to the given platform.
Differential Revision: https://reviews.llvm.org/D115246
Added:
Modified:
lldb/source/Plugins/Platform/QemuUser/PlatformQemuUser.cpp
lldb/source/Plugins/Platform/QemuUser/PlatformQemuUser.h
lldb/source/Plugins/Platform/QemuUser/PlatformQemuUserProperties.td
lldb/test/API/qemu/TestQemuLaunch.py
lldb/test/API/qemu/qemu.py
Removed:
################################################################################
diff --git a/lldb/source/Plugins/Platform/QemuUser/PlatformQemuUser.cpp b/lldb/source/Plugins/Platform/QemuUser/PlatformQemuUser.cpp
index 82b9bc078ce6c..3bcb1e12e0bbf 100644
--- a/lldb/source/Plugins/Platform/QemuUser/PlatformQemuUser.cpp
+++ b/lldb/source/Plugins/Platform/QemuUser/PlatformQemuUser.cpp
@@ -54,6 +54,13 @@ class PluginProperties : public Properties {
result);
return result;
}
+
+ Environment GetTargetEnvVars() {
+ Args args;
+ m_collection_sp->GetPropertyAtIndexAsArgs(nullptr, ePropertyTargetEnvVars,
+ args);
+ return Environment(args);
+ }
};
static PluginProperties &GetGlobalProperties() {
@@ -105,6 +112,42 @@ static auto get_arg_range(const Args &args) {
args.GetArgumentArrayRef().end());
}
+// Returns the emulator environment which result in the desired environment
+// being presented to the emulated process. We want to be careful about
+// preserving the host environment, as it may contain entries (LD_LIBRARY_PATH,
+// for example) needed for the operation of the emulator itself.
+static Environment ComputeLaunchEnvironment(Environment target,
+ Environment host) {
+ std::vector<std::string> set_env;
+ for (const auto &KV : target) {
+ // If the host value
diff ers from the target (or is unset), then set it
+ // through QEMU_SET_ENV. Identical entries will be forwarded automatically.
+ auto host_it = host.find(KV.first());
+ if (host_it == host.end() || host_it->second != KV.second)
+ set_env.push_back(Environment::compose(KV));
+ }
+
+ std::vector<llvm::StringRef> unset_env;
+ for (const auto &KV : host) {
+ // If the target is missing some host entries, then unset them through
+ // QEMU_UNSET_ENV.
+ if (target.count(KV.first()) == 0)
+ unset_env.push_back(KV.first());
+ }
+
+ // The actual QEMU_(UN)SET_ENV variables should not be forwarded to the
+ // target.
+ if (!set_env.empty()) {
+ host["QEMU_SET_ENV"] = llvm::join(set_env, ",");
+ unset_env.push_back("QEMU_SET_ENV");
+ }
+ if (!unset_env.empty()) {
+ unset_env.push_back("QEMU_UNSET_ENV");
+ host["QEMU_UNSET_ENV"] = llvm::join(unset_env, ",");
+ }
+ return host;
+}
+
lldb::ProcessSP PlatformQemuUser::DebugProcess(ProcessLaunchInfo &launch_info,
Debugger &debugger,
Target &target, Status &error) {
@@ -130,6 +173,8 @@ lldb::ProcessSP PlatformQemuUser::DebugProcess(ProcessLaunchInfo &launch_info,
get_arg_range(args));
launch_info.SetArguments(args, true);
+ launch_info.GetEnvironment() = ComputeLaunchEnvironment(
+ std::move(launch_info.GetEnvironment()), Host::GetEnvironment());
launch_info.SetLaunchInSeparateProcessGroup(true);
launch_info.GetFlags().Clear(eLaunchFlagDebug);
launch_info.SetMonitorProcessCallback(ProcessLaunchInfo::NoOpMonitorCallback,
@@ -166,3 +211,10 @@ lldb::ProcessSP PlatformQemuUser::DebugProcess(ProcessLaunchInfo &launch_info,
process_sp->WaitForProcessToStop(llvm::None, nullptr, false, listener_sp);
return process_sp;
}
+
+Environment PlatformQemuUser::GetEnvironment() {
+ Environment env = Host::GetEnvironment();
+ for (const auto &KV : GetGlobalProperties().GetTargetEnvVars())
+ env[KV.first()] = KV.second;
+ return env;
+}
diff --git a/lldb/source/Plugins/Platform/QemuUser/PlatformQemuUser.h b/lldb/source/Plugins/Platform/QemuUser/PlatformQemuUser.h
index f4f5d224a8cdf..71df1b7b7811d 100644
--- a/lldb/source/Plugins/Platform/QemuUser/PlatformQemuUser.h
+++ b/lldb/source/Plugins/Platform/QemuUser/PlatformQemuUser.h
@@ -45,7 +45,7 @@ class PlatformQemuUser : public Platform {
void CalculateTrapHandlerSymbolNames() override {}
- Environment GetEnvironment() override { return Host::GetEnvironment(); }
+ Environment GetEnvironment() override;
private:
static lldb::PlatformSP CreateInstance(bool force, const ArchSpec *arch);
diff --git a/lldb/source/Plugins/Platform/QemuUser/PlatformQemuUserProperties.td b/lldb/source/Plugins/Platform/QemuUser/PlatformQemuUserProperties.td
index 19de9c810841e..2792e2cef0349 100644
--- a/lldb/source/Plugins/Platform/QemuUser/PlatformQemuUserProperties.td
+++ b/lldb/source/Plugins/Platform/QemuUser/PlatformQemuUserProperties.td
@@ -13,4 +13,7 @@ let Definition = "platformqemuuser" in {
Global,
DefaultStringValue<"">,
Desc<"Extra arguments to pass to the emulator.">;
+ def TargetEnvVars: Property<"target-env-vars", "Dictionary">,
+ ElementType<"String">,
+ Desc<"Extra variables to add to emulated target environment.">;
}
diff --git a/lldb/test/API/qemu/TestQemuLaunch.py b/lldb/test/API/qemu/TestQemuLaunch.py
index 259b381d26721..54312495393ef 100644
--- a/lldb/test/API/qemu/TestQemuLaunch.py
+++ b/lldb/test/API/qemu/TestQemuLaunch.py
@@ -43,7 +43,7 @@ def setUp(self):
self.set_emulator_setting("architecture", self.getArchitecture())
self.set_emulator_setting("emulator-path", emulator)
- def _run_and_get_state(self):
+ def _create_target(self):
self.build()
exe = self.getBuildArtifact()
@@ -52,11 +52,21 @@ def _run_and_get_state(self):
target = self.dbg.CreateTarget(exe, '', 'qemu-user', False, error)
self.assertSuccess(error)
self.assertEqual(target.GetPlatform().GetName(), "qemu-user")
+ return target
+
+ def _run_and_get_state(self, target=None, info=None):
+ if target is None:
+ target = self._create_target()
+
+ if info is None:
+ info = target.GetLaunchInfo()
# "Launch" the process. Our fake qemu implementation will pretend it
# immediately exited.
- process = target.LaunchSimple(
- ["dump:" + self.getBuildArtifact("state.log")], None, None)
+ info.SetArguments(["dump:" + self.getBuildArtifact("state.log")], True)
+ error = lldb.SBError()
+ process = target.Launch(info, error)
+ self.assertSuccess(error)
self.assertIsNotNone(process)
self.assertEqual(process.GetState(), lldb.eStateExited)
self.assertEqual(process.GetExitStatus(), 0x47)
@@ -73,25 +83,21 @@ def test_basic_launch(self):
["dump:" + self.getBuildArtifact("state.log")])
def test_stdio_pty(self):
- self.build()
- exe = self.getBuildArtifact()
-
- # Create a target using our platform
- error = lldb.SBError()
- target = self.dbg.CreateTarget(exe, '', 'qemu-user', False, error)
- self.assertSuccess(error)
+ target = self._create_target()
- info = lldb.SBLaunchInfo([
+ info = target.GetLaunchInfo()
+ info.SetArguments([
"stdin:stdin",
"stdout:STDOUT CONTENT\n",
"stderr:STDERR CONTENT\n",
"dump:" + self.getBuildArtifact("state.log"),
- ])
+ ], False)
listener = lldb.SBListener("test_stdio")
info.SetListener(listener)
self.dbg.SetAsync(True)
+ error = lldb.SBError()
process = target.Launch(info, error)
self.assertSuccess(error)
lldbutil.expect_state_changes(self, listener, process,
@@ -152,14 +158,9 @@ def test_bad_emulator_path(self):
self.set_emulator_setting("emulator-path",
self.getBuildArtifact("nonexistent.file"))
- self.build()
- exe = self.getBuildArtifact()
-
- error = lldb.SBError()
- target = self.dbg.CreateTarget(exe, '', 'qemu-user', False, error)
- self.assertEqual(target.GetPlatform().GetName(), "qemu-user")
- self.assertSuccess(error)
+ target = self._create_target()
info = lldb.SBLaunchInfo([])
+ error = lldb.SBError()
target.Launch(info, error)
self.assertTrue(error.Fail())
self.assertIn("doesn't exist", error.GetCString())
@@ -169,3 +170,49 @@ def test_extra_args(self):
state = self._run_and_get_state()
self.assertEqual(state["fake-arg"], "fake-value")
+
+ def test_target_env_vars(self):
+ # First clear any global environment to have a clean slate for this test
+ self.runCmd("settings clear target.env-vars")
+ self.runCmd("settings clear target.unset-env-vars")
+
+ def var(i):
+ return "LLDB_TEST_QEMU_VAR%d" % i
+
+ # Set some variables in the host environment.
+ for i in range(4):
+ os.environ[var(i)]="from host"
+ def cleanup():
+ for i in range(4):
+ del os.environ[var(i)]
+ self.addTearDownHook(cleanup)
+
+ # And through the platform setting.
+ self.set_emulator_setting("target-env-vars",
+ "%s='from platform' %s='from platform'" % (var(1), var(2)))
+
+ target = self._create_target()
+ info = target.GetLaunchInfo()
+ env = info.GetEnvironment()
+
+ # Platform settings should trump host values.
+ self.assertEqual(env.Get(var(0)), "from host")
+ self.assertEqual(env.Get(var(1)), "from platform")
+ self.assertEqual(env.Get(var(2)), "from platform")
+ self.assertEqual(env.Get(var(3)), "from host")
+
+ # Finally, make some launch_info specific changes.
+ env.Set(var(2), "from target", overwrite=True)
+ env.Unset(var(3))
+ info.SetEnvironment(env, append=False)
+
+ # Now check everything. Launch info changes should trump everything, but
+ # only for the target environment -- the emulator should still get the
+ # host values.
+ state = self._run_and_get_state(target, info)
+ for i in range(4):
+ self.assertEqual(state["environ"][var(i)], "from host")
+ self.assertEqual(state["environ"]["QEMU_SET_ENV"],
+ "%s=from platform,%s=from target" % (var(1), var(2)))
+ self.assertEqual(state["environ"]["QEMU_UNSET_ENV"],
+ "%s,QEMU_SET_ENV,QEMU_UNSET_ENV" % var(3))
diff --git a/lldb/test/API/qemu/qemu.py b/lldb/test/API/qemu/qemu.py
index 4b94c7689657e..a74976881cbc5 100755
--- a/lldb/test/API/qemu/qemu.py
+++ b/lldb/test/API/qemu/qemu.py
@@ -1,6 +1,7 @@
import argparse
import socket
import json
+import os
import sys
import use_lldb_suite
@@ -60,7 +61,9 @@ def main():
parser.add_argument("args", nargs=argparse.REMAINDER)
args = parser.parse_args()
- emulator = FakeEmulator(args.g, vars(args))
+ state = vars(args)
+ state["environ"] = dict(os.environ)
+ emulator = FakeEmulator(args.g, state)
emulator.run()
if __name__ == "__main__":
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