[v2,1/2] Add attributes and methods to gdb.Inferior
Commit Message
This adds two new attributes and three new methods to gdb.Inferior.
The attributes let Python code see the command-line arguments and the
name of "main". Argument setting is also supported.
The methods let Python code manipulate the inferior's environment
variables.
Reviewed-By: Eli Zaretskii <eliz@gnu.org>
---
gdb/NEWS | 10 ++
gdb/doc/python.texi | 44 ++++++++
gdb/python/py-inferior.c | 169 +++++++++++++++++++++++++++++++
gdb/testsuite/gdb.ada/py_range.exp | 4 +
gdb/testsuite/gdb.python/py-inferior.exp | 36 +++++++
5 files changed, 263 insertions(+)
Comments
Tom Tromey via Gdb-patches <gdb-patches@sourceware.org> writes:
> This adds two new attributes and three new methods to gdb.Inferior.
>
> The attributes let Python code see the command-line arguments and the
> name of "main". Argument setting is also supported.
>
> The methods let Python code manipulate the inferior's environment
> variables.
>
> Reviewed-By: Eli Zaretskii <eliz@gnu.org>
LGTM.
Reviewed-By: Andrew Burgess <aburgess@redhat.com>
Thanks,
Andrew
> ---
> gdb/NEWS | 10 ++
> gdb/doc/python.texi | 44 ++++++++
> gdb/python/py-inferior.c | 169 +++++++++++++++++++++++++++++++
> gdb/testsuite/gdb.ada/py_range.exp | 4 +
> gdb/testsuite/gdb.python/py-inferior.exp | 36 +++++++
> 5 files changed, 263 insertions(+)
>
> diff --git a/gdb/NEWS b/gdb/NEWS
> index b82114d80b0..19bbb41c32f 100644
> --- a/gdb/NEWS
> +++ b/gdb/NEWS
> @@ -192,6 +192,16 @@ info main
> - Changes are backwards compatible, the older API can still be
> used to disassemble instructions without styling.
>
> + ** gdb.Inferior now has a new "arguments" attribute. This holds the
> + command-line arguments to the inferior, if known.
> +
> + ** gdb.Inferior now has a new "main_name" attribute. This holds the
> + name of the inferior's "main", if known.
> +
> + ** gdb.Inferior now has new methods "clear_env", "set_env", and
> + "unset_env". These can be used to modify the inferior's
> + environment before it is started.
> +
> *** Changes in GDB 13
>
> * MI version 1 is deprecated, and will be removed in GDB 14.
> diff --git a/gdb/doc/python.texi b/gdb/doc/python.texi
> index 5d714ee1ca3..4bdd52466d0 100644
> --- a/gdb/doc/python.texi
> +++ b/gdb/doc/python.texi
> @@ -3446,10 +3446,30 @@ Boolean signaling whether the inferior was created using `attach', or
> started by @value{GDBN} itself.
> @end defvar
>
> +@defvar Inferior.main_name
> +A string holding the name of this inferior's ``main'' function, if it
> +can be determined. If the name of main is not known, this is
> +@code{None}.
> +@end defvar
> +
> @defvar Inferior.progspace
> The inferior's program space. @xref{Progspaces In Python}.
> @end defvar
>
> +@defvar Inferior.arguments
> +The inferior's command line arguments, if known. This corresponds to
> +the @code{set args} and @code{show args} commands. @xref{Arguments}.
> +
> +When accessed, the value is a string holding all the arguments. The
> +contents are quoted as they would be when passed to the shell. If
> +there are no arguments, the value is @code{None}.
> +
> +Either a string or a sequence of strings can be assigned to this
> +attribute. When a string is assigned, it is assumed to have any
> +necessary quoting for the shell; when a sequence is assigned, the
> +quoting is applied by @value{GDBN}.
> +@end defvar
> +
> A @code{gdb.Inferior} object has the following methods:
>
> @defun Inferior.is_valid ()
> @@ -3517,6 +3537,30 @@ the same functionality, but use of @code{Inferior.thread_from_thread_handle}
> is deprecated.
> @end defun
>
> +
> +The environment that will be passed to the inferior can be changed
> +from Python by using the following methods. These methods only take
> +effect when the inferior is started -- they will not affect an
> +inferior that is already executing.
> +
> +@findex Inferior.clear_env
> +@defun Inferior.clear_env ()
> +Clear the current environment variables that will be passed to this
> +inferior.
> +@end defun
> +
> +@findex Inferior.set_env
> +@defun Inferior.set_env (name, value)
> +Set the environment variable @var{name} to have the indicated value.
> +Both parameters must be strings.
> +@end defun
> +
> +@findex Inferior.unset_env
> +@defun Inferior.unset_env (name)
> +Unset the environment variable @var{name}. @var{name} must be a
> +string.
> +@end defun
> +
> @node Events In Python
> @subsubsection Events In Python
> @cindex inferior events in Python
> diff --git a/gdb/python/py-inferior.c b/gdb/python/py-inferior.c
> index 982d0f803a0..8c4871dfa89 100644
> --- a/gdb/python/py-inferior.c
> +++ b/gdb/python/py-inferior.c
> @@ -770,6 +770,162 @@ infpy_repr (PyObject *obj)
> inf->num, inf->pid);
> }
>
> +/* Implement clear_env. */
> +
> +static PyObject *
> +infpy_clear_env (PyObject *obj)
> +{
> + inferior_object *self = (inferior_object *) obj;
> +
> + INFPY_REQUIRE_VALID (self);
> +
> + self->inferior->environment.clear ();
> + Py_RETURN_NONE;
> +}
> +
> +/* Implement set_env. */
> +
> +static PyObject *
> +infpy_set_env (PyObject *obj, PyObject *args, PyObject *kw)
> +{
> + inferior_object *self = (inferior_object *) obj;
> + INFPY_REQUIRE_VALID (self);
> +
> + const char *name, *val;
> + static const char *keywords[] = { "name", "value", nullptr };
> +
> + if (!gdb_PyArg_ParseTupleAndKeywords (args, kw, "ss", keywords,
> + &name, &val))
> + return nullptr;
> +
> + self->inferior->environment.set (name, val);
> + Py_RETURN_NONE;
> +}
> +
> +/* Implement unset_env. */
> +
> +static PyObject *
> +infpy_unset_env (PyObject *obj, PyObject *args, PyObject *kw)
> +{
> + inferior_object *self = (inferior_object *) obj;
> + INFPY_REQUIRE_VALID (self);
> +
> + const char *name;
> + static const char *keywords[] = { "name", nullptr };
> + if (!gdb_PyArg_ParseTupleAndKeywords (args, kw, "s", keywords, &name))
> + return nullptr;
> +
> + self->inferior->environment.unset (name);
> + Py_RETURN_NONE;
> +}
> +
> +/* Getter for "arguments". */
> +
> +static PyObject *
> +infpy_get_args (PyObject *self, void *closure)
> +{
> + inferior_object *inf = (inferior_object *) self;
> +
> + INFPY_REQUIRE_VALID (inf);
> +
> + const std::string &args = inf->inferior->args ();
> + if (args.empty ())
> + Py_RETURN_NONE;
> +
> + return host_string_to_python_string (args.c_str ()).release ();
> +}
> +
> +/* Setter for "arguments". */
> +
> +static int
> +infpy_set_args (PyObject *self, PyObject *value, void *closure)
> +{
> + inferior_object *inf = (inferior_object *) self;
> +
> + if (!inf->inferior)
> + {
> + PyErr_SetString (PyExc_RuntimeError, _("Inferior no longer exists."));
> + return -1;
> + }
> +
> + if (value == nullptr)
> + {
> + PyErr_SetString (PyExc_TypeError,
> + _("Cannot delete 'arguments' attribute."));
> + return -1;
> + }
> +
> + if (gdbpy_is_string (value))
> + {
> + gdb::unique_xmalloc_ptr<char> str = python_string_to_host_string (value);
> + if (str == nullptr)
> + return -1;
> + inf->inferior->set_args (std::string (str.get ()));
> + }
> + else if (PySequence_Check (value))
> + {
> + std::vector<gdb::unique_xmalloc_ptr<char>> args;
> + Py_ssize_t len = PySequence_Size (value);
> + if (len == -1)
> + return -1;
> + for (Py_ssize_t i = 0; i < len; ++i)
> + {
> + gdbpy_ref<> item (PySequence_ITEM (value, i));
> + if (item == nullptr)
> + return -1;
> + gdb::unique_xmalloc_ptr<char> str
> + = python_string_to_host_string (item.get ());
> + if (str == nullptr)
> + return -1;
> + args.push_back (std::move (str));
> + }
> + std::vector<char *> argvec;
> + for (const auto &arg : args)
> + argvec.push_back (arg.get ());
> + gdb::array_view<char * const> view (argvec.data (), argvec.size ());
> + inf->inferior->set_args (view);
> + }
> + else
> + {
> + PyErr_SetString (PyExc_TypeError,
> + _("string or sequence required for 'arguments'"));
> + return -1;
> + }
> + return 0;
> +}
> +
> +/* Getter for "main_name". */
> +
> +static PyObject *
> +infpy_get_main_name (PyObject *self, void *closure)
> +{
> + inferior_object *inf = (inferior_object *) self;
> +
> + INFPY_REQUIRE_VALID (inf);
> +
> + const char *name = nullptr;
> + try
> + {
> + /* This is unfortunate but the implementation of main_name can
> + reach into memory. */
> + scoped_restore_current_inferior restore_inferior;
> + set_current_inferior (inf->inferior);
> +
> + scoped_restore_current_program_space restore_current_progspace;
> + set_current_program_space (inf->inferior->pspace);
> +
> + name = main_name ();
> + }
> + catch (const gdb_exception &except)
> + {
> + /* We can just ignore this. */
> + }
> +
> + if (name == nullptr)
> + Py_RETURN_NONE;
> +
> + return host_string_to_python_string (name).release ();
> +}
>
> static void
> infpy_dealloc (PyObject *obj)
> @@ -844,6 +1000,8 @@ GDBPY_INITIALIZE_FILE (gdbpy_initialize_inferior);
>
> static gdb_PyGetSetDef inferior_object_getset[] =
> {
> + { "arguments", infpy_get_args, infpy_set_args,
> + "Arguments to this program.", nullptr },
> { "num", infpy_get_num, NULL, "ID of inferior, as assigned by GDB.", NULL },
> { "connection", infpy_get_connection, NULL,
> "The gdb.TargetConnection for this inferior.", NULL },
> @@ -854,6 +1012,8 @@ static gdb_PyGetSetDef inferior_object_getset[] =
> { "was_attached", infpy_get_was_attached, NULL,
> "True if the inferior was created using 'attach'.", NULL },
> { "progspace", infpy_get_progspace, NULL, "Program space of this inferior" },
> + { "main_name", infpy_get_main_name, nullptr,
> + "Name of 'main' function, if known.", nullptr },
> { NULL }
> };
>
> @@ -889,6 +1049,15 @@ Return thread object corresponding to thread handle." },
> { "architecture", (PyCFunction) infpy_architecture, METH_NOARGS,
> "architecture () -> gdb.Architecture\n\
> Return architecture of this inferior." },
> + { "clear_env", (PyCFunction) infpy_clear_env, METH_NOARGS,
> + "clear_env () -> None\n\
> +Clear environment of this inferior." },
> + { "set_env", (PyCFunction) infpy_set_env, METH_VARARGS | METH_KEYWORDS,
> + "set_env (name, value) -> None\n\
> +Set an environment variable of this inferior." },
> + { "unset_env", (PyCFunction) infpy_unset_env, METH_VARARGS | METH_KEYWORDS,
> + "unset_env (name) -> None\n\
> +Unset an environment of this inferior." },
> { NULL }
> };
>
> diff --git a/gdb/testsuite/gdb.ada/py_range.exp b/gdb/testsuite/gdb.ada/py_range.exp
> index 2972db21827..833493bad95 100644
> --- a/gdb/testsuite/gdb.ada/py_range.exp
> +++ b/gdb/testsuite/gdb.ada/py_range.exp
> @@ -42,3 +42,7 @@ gdb_test "python print(gdb.parse_and_eval('si').type)" \
> "foo\\.small_integer" "print type"
> gdb_test "python print(gdb.parse_and_eval('si').type.name)" \
> "foo\\.small_integer" "print type name"
> +
> +gdb_test "python print(gdb.selected_inferior().main_name)" \
> + "_ada_foo" \
> + "print main name"
> diff --git a/gdb/testsuite/gdb.python/py-inferior.exp b/gdb/testsuite/gdb.python/py-inferior.exp
> index 424050a6166..58deece5d5f 100644
> --- a/gdb/testsuite/gdb.python/py-inferior.exp
> +++ b/gdb/testsuite/gdb.python/py-inferior.exp
> @@ -342,3 +342,39 @@ with_test_prefix "architecture" {
> "True" \
> "inferior architecture matches frame architecture"
> }
> +
> +gdb_test "python print(gdb.selected_inferior().main_name)" \
> + "main" \
> + "print main name"
> +
> +gdb_test_no_output "set args x y z"
> +gdb_test "python print(gdb.selected_inferior().arguments)" \
> + "x y z" \
> + "print arguments"
> +
> +gdb_test_no_output "python gdb.selected_inferior().arguments = 'a b c'" \
> + "set arguments from string"
> +gdb_test "show args" \
> + [string_to_regexp "Argument list to give program being debugged when it is started is \"a b c\"."] \
> + "show args from string"
> +
> +gdb_test_no_output "python gdb.selected_inferior().arguments = \['a', 'b c'\]" \
> + "set arguments from list"
> +gdb_test "show args" \
> + [string_to_regexp "Argument list to give program being debugged when it is started is \"a b\\ c\"."] \
> + "show args from list"
> +
> +gdb_test_no_output "python gdb.selected_inferior().clear_env()" \
> + "clear environment"
> +gdb_test_no_output "show environment"
> +
> +gdb_test_no_output "python gdb.selected_inferior().set_env('DEI', 'value')" \
> + "set environment variable"
> +gdb_test "show environment" \
> + "DEI=value" \
> + "examine environment variable"
> +
> +gdb_test_no_output "python gdb.selected_inferior().unset_env('DEI')" \
> + "unset environment variable"
> +gdb_test_no_output "show environment" \
> + "environment is empty again"
>
> --
> 2.40.0
@@ -192,6 +192,16 @@ info main
- Changes are backwards compatible, the older API can still be
used to disassemble instructions without styling.
+ ** gdb.Inferior now has a new "arguments" attribute. This holds the
+ command-line arguments to the inferior, if known.
+
+ ** gdb.Inferior now has a new "main_name" attribute. This holds the
+ name of the inferior's "main", if known.
+
+ ** gdb.Inferior now has new methods "clear_env", "set_env", and
+ "unset_env". These can be used to modify the inferior's
+ environment before it is started.
+
*** Changes in GDB 13
* MI version 1 is deprecated, and will be removed in GDB 14.
@@ -3446,10 +3446,30 @@ Boolean signaling whether the inferior was created using `attach', or
started by @value{GDBN} itself.
@end defvar
+@defvar Inferior.main_name
+A string holding the name of this inferior's ``main'' function, if it
+can be determined. If the name of main is not known, this is
+@code{None}.
+@end defvar
+
@defvar Inferior.progspace
The inferior's program space. @xref{Progspaces In Python}.
@end defvar
+@defvar Inferior.arguments
+The inferior's command line arguments, if known. This corresponds to
+the @code{set args} and @code{show args} commands. @xref{Arguments}.
+
+When accessed, the value is a string holding all the arguments. The
+contents are quoted as they would be when passed to the shell. If
+there are no arguments, the value is @code{None}.
+
+Either a string or a sequence of strings can be assigned to this
+attribute. When a string is assigned, it is assumed to have any
+necessary quoting for the shell; when a sequence is assigned, the
+quoting is applied by @value{GDBN}.
+@end defvar
+
A @code{gdb.Inferior} object has the following methods:
@defun Inferior.is_valid ()
@@ -3517,6 +3537,30 @@ the same functionality, but use of @code{Inferior.thread_from_thread_handle}
is deprecated.
@end defun
+
+The environment that will be passed to the inferior can be changed
+from Python by using the following methods. These methods only take
+effect when the inferior is started -- they will not affect an
+inferior that is already executing.
+
+@findex Inferior.clear_env
+@defun Inferior.clear_env ()
+Clear the current environment variables that will be passed to this
+inferior.
+@end defun
+
+@findex Inferior.set_env
+@defun Inferior.set_env (name, value)
+Set the environment variable @var{name} to have the indicated value.
+Both parameters must be strings.
+@end defun
+
+@findex Inferior.unset_env
+@defun Inferior.unset_env (name)
+Unset the environment variable @var{name}. @var{name} must be a
+string.
+@end defun
+
@node Events In Python
@subsubsection Events In Python
@cindex inferior events in Python
@@ -770,6 +770,162 @@ infpy_repr (PyObject *obj)
inf->num, inf->pid);
}
+/* Implement clear_env. */
+
+static PyObject *
+infpy_clear_env (PyObject *obj)
+{
+ inferior_object *self = (inferior_object *) obj;
+
+ INFPY_REQUIRE_VALID (self);
+
+ self->inferior->environment.clear ();
+ Py_RETURN_NONE;
+}
+
+/* Implement set_env. */
+
+static PyObject *
+infpy_set_env (PyObject *obj, PyObject *args, PyObject *kw)
+{
+ inferior_object *self = (inferior_object *) obj;
+ INFPY_REQUIRE_VALID (self);
+
+ const char *name, *val;
+ static const char *keywords[] = { "name", "value", nullptr };
+
+ if (!gdb_PyArg_ParseTupleAndKeywords (args, kw, "ss", keywords,
+ &name, &val))
+ return nullptr;
+
+ self->inferior->environment.set (name, val);
+ Py_RETURN_NONE;
+}
+
+/* Implement unset_env. */
+
+static PyObject *
+infpy_unset_env (PyObject *obj, PyObject *args, PyObject *kw)
+{
+ inferior_object *self = (inferior_object *) obj;
+ INFPY_REQUIRE_VALID (self);
+
+ const char *name;
+ static const char *keywords[] = { "name", nullptr };
+ if (!gdb_PyArg_ParseTupleAndKeywords (args, kw, "s", keywords, &name))
+ return nullptr;
+
+ self->inferior->environment.unset (name);
+ Py_RETURN_NONE;
+}
+
+/* Getter for "arguments". */
+
+static PyObject *
+infpy_get_args (PyObject *self, void *closure)
+{
+ inferior_object *inf = (inferior_object *) self;
+
+ INFPY_REQUIRE_VALID (inf);
+
+ const std::string &args = inf->inferior->args ();
+ if (args.empty ())
+ Py_RETURN_NONE;
+
+ return host_string_to_python_string (args.c_str ()).release ();
+}
+
+/* Setter for "arguments". */
+
+static int
+infpy_set_args (PyObject *self, PyObject *value, void *closure)
+{
+ inferior_object *inf = (inferior_object *) self;
+
+ if (!inf->inferior)
+ {
+ PyErr_SetString (PyExc_RuntimeError, _("Inferior no longer exists."));
+ return -1;
+ }
+
+ if (value == nullptr)
+ {
+ PyErr_SetString (PyExc_TypeError,
+ _("Cannot delete 'arguments' attribute."));
+ return -1;
+ }
+
+ if (gdbpy_is_string (value))
+ {
+ gdb::unique_xmalloc_ptr<char> str = python_string_to_host_string (value);
+ if (str == nullptr)
+ return -1;
+ inf->inferior->set_args (std::string (str.get ()));
+ }
+ else if (PySequence_Check (value))
+ {
+ std::vector<gdb::unique_xmalloc_ptr<char>> args;
+ Py_ssize_t len = PySequence_Size (value);
+ if (len == -1)
+ return -1;
+ for (Py_ssize_t i = 0; i < len; ++i)
+ {
+ gdbpy_ref<> item (PySequence_ITEM (value, i));
+ if (item == nullptr)
+ return -1;
+ gdb::unique_xmalloc_ptr<char> str
+ = python_string_to_host_string (item.get ());
+ if (str == nullptr)
+ return -1;
+ args.push_back (std::move (str));
+ }
+ std::vector<char *> argvec;
+ for (const auto &arg : args)
+ argvec.push_back (arg.get ());
+ gdb::array_view<char * const> view (argvec.data (), argvec.size ());
+ inf->inferior->set_args (view);
+ }
+ else
+ {
+ PyErr_SetString (PyExc_TypeError,
+ _("string or sequence required for 'arguments'"));
+ return -1;
+ }
+ return 0;
+}
+
+/* Getter for "main_name". */
+
+static PyObject *
+infpy_get_main_name (PyObject *self, void *closure)
+{
+ inferior_object *inf = (inferior_object *) self;
+
+ INFPY_REQUIRE_VALID (inf);
+
+ const char *name = nullptr;
+ try
+ {
+ /* This is unfortunate but the implementation of main_name can
+ reach into memory. */
+ scoped_restore_current_inferior restore_inferior;
+ set_current_inferior (inf->inferior);
+
+ scoped_restore_current_program_space restore_current_progspace;
+ set_current_program_space (inf->inferior->pspace);
+
+ name = main_name ();
+ }
+ catch (const gdb_exception &except)
+ {
+ /* We can just ignore this. */
+ }
+
+ if (name == nullptr)
+ Py_RETURN_NONE;
+
+ return host_string_to_python_string (name).release ();
+}
static void
infpy_dealloc (PyObject *obj)
@@ -844,6 +1000,8 @@ GDBPY_INITIALIZE_FILE (gdbpy_initialize_inferior);
static gdb_PyGetSetDef inferior_object_getset[] =
{
+ { "arguments", infpy_get_args, infpy_set_args,
+ "Arguments to this program.", nullptr },
{ "num", infpy_get_num, NULL, "ID of inferior, as assigned by GDB.", NULL },
{ "connection", infpy_get_connection, NULL,
"The gdb.TargetConnection for this inferior.", NULL },
@@ -854,6 +1012,8 @@ static gdb_PyGetSetDef inferior_object_getset[] =
{ "was_attached", infpy_get_was_attached, NULL,
"True if the inferior was created using 'attach'.", NULL },
{ "progspace", infpy_get_progspace, NULL, "Program space of this inferior" },
+ { "main_name", infpy_get_main_name, nullptr,
+ "Name of 'main' function, if known.", nullptr },
{ NULL }
};
@@ -889,6 +1049,15 @@ Return thread object corresponding to thread handle." },
{ "architecture", (PyCFunction) infpy_architecture, METH_NOARGS,
"architecture () -> gdb.Architecture\n\
Return architecture of this inferior." },
+ { "clear_env", (PyCFunction) infpy_clear_env, METH_NOARGS,
+ "clear_env () -> None\n\
+Clear environment of this inferior." },
+ { "set_env", (PyCFunction) infpy_set_env, METH_VARARGS | METH_KEYWORDS,
+ "set_env (name, value) -> None\n\
+Set an environment variable of this inferior." },
+ { "unset_env", (PyCFunction) infpy_unset_env, METH_VARARGS | METH_KEYWORDS,
+ "unset_env (name) -> None\n\
+Unset an environment of this inferior." },
{ NULL }
};
@@ -42,3 +42,7 @@ gdb_test "python print(gdb.parse_and_eval('si').type)" \
"foo\\.small_integer" "print type"
gdb_test "python print(gdb.parse_and_eval('si').type.name)" \
"foo\\.small_integer" "print type name"
+
+gdb_test "python print(gdb.selected_inferior().main_name)" \
+ "_ada_foo" \
+ "print main name"
@@ -342,3 +342,39 @@ with_test_prefix "architecture" {
"True" \
"inferior architecture matches frame architecture"
}
+
+gdb_test "python print(gdb.selected_inferior().main_name)" \
+ "main" \
+ "print main name"
+
+gdb_test_no_output "set args x y z"
+gdb_test "python print(gdb.selected_inferior().arguments)" \
+ "x y z" \
+ "print arguments"
+
+gdb_test_no_output "python gdb.selected_inferior().arguments = 'a b c'" \
+ "set arguments from string"
+gdb_test "show args" \
+ [string_to_regexp "Argument list to give program being debugged when it is started is \"a b c\"."] \
+ "show args from string"
+
+gdb_test_no_output "python gdb.selected_inferior().arguments = \['a', 'b c'\]" \
+ "set arguments from list"
+gdb_test "show args" \
+ [string_to_regexp "Argument list to give program being debugged when it is started is \"a b\\ c\"."] \
+ "show args from list"
+
+gdb_test_no_output "python gdb.selected_inferior().clear_env()" \
+ "clear environment"
+gdb_test_no_output "show environment"
+
+gdb_test_no_output "python gdb.selected_inferior().set_env('DEI', 'value')" \
+ "set environment variable"
+gdb_test "show environment" \
+ "DEI=value" \
+ "examine environment variable"
+
+gdb_test_no_output "python gdb.selected_inferior().unset_env('DEI')" \
+ "unset environment variable"
+gdb_test_no_output "show environment" \
+ "environment is empty again"