[Lldb-commits] [lldb] b4a6e63 - [lldb/Target] Rework the way the inferior environment is created

Fred Riss via lldb-commits lldb-commits at lists.llvm.org
Mon Mar 23 07:59:08 PDT 2020


Author: Fred Riss
Date: 2020-03-23T07:58:34-07:00
New Revision: b4a6e63ea12309bf667d1569a20ec5b081cbf2a4

URL: https://github.com/llvm/llvm-project/commit/b4a6e63ea12309bf667d1569a20ec5b081cbf2a4
DIFF: https://github.com/llvm/llvm-project/commit/b4a6e63ea12309bf667d1569a20ec5b081cbf2a4.diff

LOG: [lldb/Target] Rework the way the inferior environment is created

Summary:
The interactions between the environment settings (`target.env-vars`,
`target.inherit-env`) and the inferior life-cycle are non-obvious
today. For example, if `target.inherit-env` is set, the `target.env-vars`
setting will be augmented with the contents of the host environment
the first time the launch environment is queried (usually at
launch). After that point, toggling `target.inherit-env` will have no
effect as there's no tracking of what comes from the host and what is
a user setting.

This patch computes the environment every time it is queried rather
than updating the contents of the `target.env-vars` property. This
means that toggling the `target.inherit-env` property later will now
have the intended effect.

This patch also adds a `target.unset-env-vars` settings that one can
use to remove variables from the launch environment. Using this, you
can inherit all but a few of the host environment.

The way the launch environment is constructed is:
  1/ if `target.inherit-env` is set, then read the host environment
  into the launch environment.
  2/ Remove for the environment the variables listed in
  `target.unset-env`.
  3/ Augment the launch environment with the contents of
  `target.env-vars`. This overrides any common values with the host
  environment.

The one functional difference here that could be seen as a regression
is that `target.env-vars` will not contain the inferior environment
after launch. The patch implements a better alternative in the
`target show-launch-environment` command which will return the
environment computed through the above rules.

Reviewers: labath, jingham

Subscribers: lldb-commits

Tags: #lldb

Differential Revision: https://reviews.llvm.org/D76470

Added: 
    

Modified: 
    lldb/include/lldb/Target/Target.h
    lldb/source/Commands/CommandObjectTarget.cpp
    lldb/source/Target/Target.cpp
    lldb/source/Target/TargetProperties.td
    lldb/test/API/commands/settings/TestSettings.py

Removed: 
    


################################################################################
diff  --git a/lldb/include/lldb/Target/Target.h b/lldb/include/lldb/Target/Target.h
index 2e7932f49e6f..77cda4998192 100644
--- a/lldb/include/lldb/Target/Target.h
+++ b/lldb/include/lldb/Target/Target.h
@@ -225,9 +225,12 @@ class TargetProperties : public Properties {
   void DisableASLRValueChangedCallback();
   void DisableSTDIOValueChangedCallback();
 
+  Environment ComputeEnvironment() const;
+
   // Member variables.
   ProcessLaunchInfo m_launch_info;
   std::unique_ptr<TargetExperimentalProperties> m_experimental_properties_up;
+  Target *m_target;
 };
 
 class EvaluateExpressionOptions {

diff  --git a/lldb/source/Commands/CommandObjectTarget.cpp b/lldb/source/Commands/CommandObjectTarget.cpp
index c70117c7a80a..95f81fc6cd54 100644
--- a/lldb/source/Commands/CommandObjectTarget.cpp
+++ b/lldb/source/Commands/CommandObjectTarget.cpp
@@ -682,6 +682,41 @@ class CommandObjectTargetDelete : public CommandObjectParsed {
   OptionGroupBoolean m_cleanup_option;
 };
 
+class CommandObjectTargetShowLaunchEnvironment : public CommandObjectParsed {
+public:
+  CommandObjectTargetShowLaunchEnvironment(CommandInterpreter &interpreter)
+      : CommandObjectParsed(
+            interpreter, "target show-launch-environment",
+            "Shows the environment being passed to the process when launched, "
+            "taking info account 3 settings: target.env-vars, "
+            "target.inherit-env and target.unset-env-vars.",
+            nullptr, eCommandRequiresTarget) {}
+
+  ~CommandObjectTargetShowLaunchEnvironment() override = default;
+
+protected:
+  bool DoExecute(Args &args, CommandReturnObject &result) override {
+    Target *target = m_exe_ctx.GetTargetPtr();
+    Environment env = target->GetEnvironment();
+
+    std::vector<Environment::value_type *> env_vector;
+    env_vector.reserve(env.size());
+    for (auto &KV : env)
+      env_vector.push_back(&KV);
+    std::sort(env_vector.begin(), env_vector.end(),
+              [](Environment::value_type *a, Environment::value_type *b) {
+                return a->first() < b->first();
+              });
+
+    auto &strm = result.GetOutputStream();
+    for (auto &KV : env_vector)
+      strm.Format("{0}={1}\n", KV->first(), KV->second);
+
+    result.SetStatus(eReturnStatusSuccessFinishResult);
+    return result.Succeeded();
+  }
+};
+
 #pragma mark CommandObjectTargetVariable
 
 // "target variable"
@@ -4876,6 +4911,9 @@ CommandObjectMultiwordTarget::CommandObjectMultiwordTarget(
                  CommandObjectSP(new CommandObjectTargetList(interpreter)));
   LoadSubCommand("select",
                  CommandObjectSP(new CommandObjectTargetSelect(interpreter)));
+  LoadSubCommand("show-launch-environment",
+                 CommandObjectSP(new CommandObjectTargetShowLaunchEnvironment(
+                     interpreter)));
   LoadSubCommand(
       "stop-hook",
       CommandObjectSP(new CommandObjectMultiwordTargetStopHooks(interpreter)));

diff  --git a/lldb/source/Target/Target.cpp b/lldb/source/Target/Target.cpp
index 0162ca838e78..e2c808120877 100644
--- a/lldb/source/Target/Target.cpp
+++ b/lldb/source/Target/Target.cpp
@@ -3344,16 +3344,13 @@ enum {
 
 class TargetOptionValueProperties : public OptionValueProperties {
 public:
-  TargetOptionValueProperties(ConstString name)
-      : OptionValueProperties(name), m_target(nullptr), m_got_host_env(false) {}
+  TargetOptionValueProperties(ConstString name) : OptionValueProperties(name) {}
 
   // This constructor is used when creating TargetOptionValueProperties when it
   // is part of a new lldb_private::Target instance. It will copy all current
   // global property values as needed
-  TargetOptionValueProperties(Target *target,
-                              const TargetPropertiesSP &target_properties_sp)
-      : OptionValueProperties(*target_properties_sp->GetValueProperties()),
-        m_target(target), m_got_host_env(false) {}
+  TargetOptionValueProperties(const TargetPropertiesSP &target_properties_sp)
+      : OptionValueProperties(*target_properties_sp->GetValueProperties()) {}
 
   const Property *GetPropertyAtIndex(const ExecutionContext *exe_ctx,
                                      bool will_modify,
@@ -3361,9 +3358,6 @@ class TargetOptionValueProperties : public OptionValueProperties {
     // When getting the value for a key from the target options, we will always
     // try and grab the setting from the current target if there is one. Else
     // we just use the one from this instance.
-    if (idx == ePropertyEnvVars)
-      GetHostEnvironmentIfNeeded();
-
     if (exe_ctx) {
       Target *target = exe_ctx->GetTargetPtr();
       if (target) {
@@ -3376,41 +3370,6 @@ class TargetOptionValueProperties : public OptionValueProperties {
     }
     return ProtectedGetPropertyAtIndex(idx);
   }
-
-  lldb::TargetSP GetTargetSP() { return m_target->shared_from_this(); }
-
-protected:
-  void GetHostEnvironmentIfNeeded() const {
-    if (!m_got_host_env) {
-      if (m_target) {
-        m_got_host_env = true;
-        const uint32_t idx = ePropertyInheritEnv;
-        if (GetPropertyAtIndexAsBoolean(
-                nullptr, idx, g_target_properties[idx].default_uint_value != 0)) {
-          PlatformSP platform_sp(m_target->GetPlatform());
-          if (platform_sp) {
-            Environment env = platform_sp->GetEnvironment();
-            OptionValueDictionary *env_dict =
-                GetPropertyAtIndexAsOptionValueDictionary(nullptr,
-                                                          ePropertyEnvVars);
-            if (env_dict) {
-              const bool can_replace = false;
-              for (const auto &KV : env) {
-                // Don't allow existing keys to be replaced with ones we get
-                // from the platform environment
-                env_dict->SetValueForKey(
-                    ConstString(KV.first()),
-                    OptionValueSP(new OptionValueString(KV.second.c_str())),
-                    can_replace);
-              }
-            }
-          }
-        }
-      }
-    }
-  }
-  Target *m_target;
-  mutable bool m_got_host_env;
 };
 
 // TargetProperties
@@ -3437,10 +3396,10 @@ TargetExperimentalProperties::TargetExperimentalProperties()
 
 // TargetProperties
 TargetProperties::TargetProperties(Target *target)
-    : Properties(), m_launch_info() {
+    : Properties(), m_launch_info(), m_target(target) {
   if (target) {
     m_collection_sp = std::make_shared<TargetOptionValueProperties>(
-        target, Target::GetGlobalProperties());
+        Target::GetGlobalProperties());
 
     // Set callbacks to update launch_info whenever "settins set" updated any
     // of these properties
@@ -3450,6 +3409,10 @@ TargetProperties::TargetProperties(Target *target)
         ePropertyRunArgs, [this] { RunArgsValueChangedCallback(); });
     m_collection_sp->SetValueChangedCallback(
         ePropertyEnvVars, [this] { EnvVarsValueChangedCallback(); });
+    m_collection_sp->SetValueChangedCallback(
+        ePropertyUnsetEnvVars, [this] { EnvVarsValueChangedCallback(); });
+    m_collection_sp->SetValueChangedCallback(
+        ePropertyInheritEnv, [this] { EnvVarsValueChangedCallback(); });
     m_collection_sp->SetValueChangedCallback(
         ePropertyInputPath, [this] { InputPathValueChangedCallback(); });
     m_collection_sp->SetValueChangedCallback(
@@ -3641,19 +3604,43 @@ void TargetProperties::SetRunArguments(const Args &args) {
   m_launch_info.GetArguments() = args;
 }
 
+Environment TargetProperties::ComputeEnvironment() const {
+  Environment env;
+
+  if (m_target &&
+      m_collection_sp->GetPropertyAtIndexAsBoolean(
+          nullptr, ePropertyInheritEnv,
+          g_target_properties[ePropertyInheritEnv].default_uint_value != 0)) {
+    if (auto platform_sp = m_target->GetPlatform()) {
+      Environment platform_env = platform_sp->GetEnvironment();
+      for (const auto &KV : platform_env)
+        env[KV.first()] = KV.second;
+    }
+  }
+
+  Args property_unset_env;
+  m_collection_sp->GetPropertyAtIndexAsArgs(nullptr, ePropertyUnsetEnvVars,
+                                            property_unset_env);
+  for (const auto &var : property_unset_env)
+    env.erase(var.ref());
+
+  Args property_env;
+  m_collection_sp->GetPropertyAtIndexAsArgs(nullptr, ePropertyEnvVars,
+                                            property_env);
+  for (const auto &KV : Environment(property_env))
+    env[KV.first()] = KV.second;
+
+  return env;
+}
+
 Environment TargetProperties::GetEnvironment() const {
-  // TODO: Get rid of the Args intermediate step
-  Args env;
-  const uint32_t idx = ePropertyEnvVars;
-  m_collection_sp->GetPropertyAtIndexAsArgs(nullptr, idx, env);
-  return Environment(env);
+  return ComputeEnvironment();
 }
 
 void TargetProperties::SetEnvironment(Environment env) {
   // TODO: Get rid of the Args intermediate step
   const uint32_t idx = ePropertyEnvVars;
   m_collection_sp->SetPropertyAtIndexFromArgs(nullptr, idx, Args(env));
-  m_launch_info.GetEnvironment() = std::move(env);
 }
 
 bool TargetProperties::GetSkipPrologue() const {
@@ -3971,7 +3958,7 @@ void TargetProperties::RunArgsValueChangedCallback() {
 }
 
 void TargetProperties::EnvVarsValueChangedCallback() {
-  m_launch_info.GetEnvironment() = GetEnvironment();
+  m_launch_info.GetEnvironment() = ComputeEnvironment();
 }
 
 void TargetProperties::InputPathValueChangedCallback() {

diff  --git a/lldb/source/Target/TargetProperties.td b/lldb/source/Target/TargetProperties.td
index 77579c66ccb0..c8dd0a12315e 100644
--- a/lldb/source/Target/TargetProperties.td
+++ b/lldb/source/Target/TargetProperties.td
@@ -80,7 +80,10 @@ let Definition = "target" in {
     Desc<"A list containing all the arguments to be passed to the executable when it is run. Note that this does NOT include the argv[0] which is in target.arg0.">;
   def EnvVars: Property<"env-vars", "Dictionary">,
     ElementType<"String">,
-    Desc<"A list of all the environment variables to be passed to the executable's environment, and their values.">;
+    Desc<"A list of user provided environment variables to be passed to the executable's environment, and their values.">;
+  def UnsetEnvVars: Property<"unset-env-vars", "Array">,
+    ElementType<"String">,
+    Desc<"A list of environment variable names to be unset in the inferior's environment. This is most useful to unset some host environment variables when target.inherit-env is true. target.env-vars takes precedence over target.unset-env-vars.">;
   def InheritEnv: Property<"inherit-env", "Boolean">,
     DefaultTrue,
     Desc<"Inherit the environment from the process that is running LLDB.">;

diff  --git a/lldb/test/API/commands/settings/TestSettings.py b/lldb/test/API/commands/settings/TestSettings.py
index b203f85de9fb..29360856a735 100644
--- a/lldb/test/API/commands/settings/TestSettings.py
+++ b/lldb/test/API/commands/settings/TestSettings.py
@@ -236,6 +236,10 @@ def do_test_run_args_and_env_vars(self, use_launchsimple):
         self.assertTrue(found_env_var,
                         "MY_ENV_VAR was not set in LunchInfo object")
 
+        self.expect(
+            'target show-launch-environment',
+            substrs=["MY_ENV_VAR=YES"])
+
         wd = self.get_process_working_directory()
         if use_launchsimple:
             process = target.LaunchSimple(None, None, wd)
@@ -256,6 +260,31 @@ def do_test_run_args_and_env_vars(self, use_launchsimple):
                 "argv[3] matches",
                 "Environment variable 'MY_ENV_VAR' successfully passed."])
 
+        # Check that env-vars overrides unset-env-vars.
+        self.runCmd('settings set target.unset-env-vars MY_ENV_VAR')
+
+        self.expect(
+            'target show-launch-environment',
+            'env-vars overrides unset-env-vars',
+            substrs=["MY_ENV_VAR=YES"])
+
+        wd = self.get_process_working_directory()
+        if use_launchsimple:
+            process = target.LaunchSimple(None, None, wd)
+            self.assertTrue(process)
+        else:
+            self.runCmd("process launch --working-dir '{0}'".format(wd),
+                RUN_SUCCEEDED)
+
+        # Read the output file produced by running the program.
+        output = lldbutil.read_file_from_process_wd(self, "output2.txt")
+
+        self.expect(
+            output,
+            exe=False,
+            substrs=[
+                "Environment variable 'MY_ENV_VAR' successfully passed."])
+
     @skipIfRemote  # it doesn't make sense to send host env to remote target
     def test_pass_host_env_vars(self):
         """Test that the host env vars are passed to the launched process."""
@@ -269,6 +298,7 @@ def test_pass_host_env_vars(self):
         def unset_env_variables():
             os.environ.pop("MY_HOST_ENV_VAR1")
             os.environ.pop("MY_HOST_ENV_VAR2")
+        self.addTearDownHook(unset_env_variables)
 
         exe = self.getBuildArtifact("a.out")
         self.runCmd("file " + exe, CURRENT_EXECUTABLE_SET)
@@ -279,7 +309,33 @@ def unset_env_variables():
             "Default inherit-env is 'true'",
             startstr="target.inherit-env (boolean) = true")
 
-        self.addTearDownHook(unset_env_variables)
+        self.expect(
+            'target show-launch-environment',
+            'Host environment is passed correctly',
+            substrs=['MY_HOST_ENV_VAR1=VAR1', 'MY_HOST_ENV_VAR2=VAR2'])
+        self.runCmd("process launch --working-dir '{0}'".format(self.get_process_working_directory()),
+                RUN_SUCCEEDED)
+
+        # Read the output file produced by running the program.
+        output = lldbutil.read_file_from_process_wd(self, "output1.txt")
+
+        self.expect(
+            output,
+            exe=False,
+            substrs=[
+                "The host environment variable 'MY_HOST_ENV_VAR1' successfully passed.",
+                "The host environment variable 'MY_HOST_ENV_VAR2' successfully passed."])
+
+        # Now test that we can prevent the inferior from inheriting the
+        # environment.
+        self.runCmd('settings set target.inherit-env false')
+
+        self.expect(
+            'target show-launch-environment',
+            'target.inherit-env affects `target show-launch-environment`',
+            matching=False,
+            substrs = ['MY_HOST_ENV_VAR1=VAR1', 'MY_HOST_ENV_VAR2=VAR2'])
+
         self.runCmd("process launch --working-dir '{0}'".format(self.get_process_working_directory()),
                 RUN_SUCCEEDED)
 
@@ -289,10 +345,42 @@ def unset_env_variables():
         self.expect(
             output,
             exe=False,
+            matching=False,
             substrs=[
                 "The host environment variable 'MY_HOST_ENV_VAR1' successfully passed.",
                 "The host environment variable 'MY_HOST_ENV_VAR2' successfully passed."])
 
+        # Now test that we can unset variables from the inherited environment.
+        self.runCmd('settings set target.inherit-env true')
+        self.runCmd('settings set target.unset-env-vars MY_HOST_ENV_VAR1')
+        self.runCmd("process launch --working-dir '{0}'".format(self.get_process_working_directory()),
+                RUN_SUCCEEDED)
+
+        # Read the output file produced by running the program.
+        output = lldbutil.read_file_from_process_wd(self, "output1.txt")
+
+        self.expect(
+            'target show-launch-environment',
+            'MY_HOST_ENV_VAR1 is unset, it shouldn\'t be in `target show-launch-environment`',
+            matching=False,
+            substrs = ['MY_HOST_ENV_VAR1=VAR1'])
+        self.expect(
+            'target show-launch-environment',
+            'MY_HOST_ENV_VAR2 shouldn be in `target show-launch-environment`',
+            substrs = ['MY_HOST_ENV_VAR2=VAR2'])
+
+        self.expect(
+            output,
+            exe=False,
+            matching=False,
+            substrs=[
+                "The host environment variable 'MY_HOST_ENV_VAR1' successfully passed."])
+        self.expect(
+            output,
+            exe=False,
+            substrs=[
+                "The host environment variable 'MY_HOST_ENV_VAR2' successfully passed."])
+
     @skipIfDarwinEmbedded   # <rdar://problem/34446098> debugserver on ios etc can't write files
     def test_set_error_output_path(self):
         """Test that setting target.error/output-path for the launched process works."""


        


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