C++ify gdb/common/environ.c

As part of the preparation necessary for my upcoming task, I'd like to
propose that we turn gdb_environ into a class.  The approach taken
here is simple: the class gdb_environ contains everything that is
needed to manipulate the environment variables.  These variables are
stored in an std::vector<char *>, which can be converted to a 'char
**' and passed as argument to functions that need it.

The usage has not changed much.  As per Pedro's suggestion, this class
uses a static factory method initialization.  This means that when an
instance is created, it is initially empty.  When needed, it has to be
initialized using the static method 'from_host_environ'.

As mentioned before, this is a preparation for an upcoming work that I
will be posting in the next few weeks or so.  For that work, I'll
probably create another data structure that will contain all the
environment variables that were set by the user using the 'set
environment' command, because I'll need access to them.  This will be
much easier with the class-ification of gdb_environ.

As noted, this has been regression-tested with the new version of
environ.exp and no regressions were found.

gdb/ChangeLog:
2017-06-20  Sergio Durigan Junior  <sergiodj@redhat.com>

	* Makefile.in (SUBDIR_UNITTESTS_SRCS): Add
	'unittests/environ-selftests.c'.
	(SUBDIR_UNITTESTS_OBS): Add 'environ-selftests.o'.
	* charset.c (find_charset_names): Declare object 'iconv_env'.
	Update code to use 'iconv_env' object.  Remove call to
	'free_environ'.
	* common/environ.c: Include <utility>.
	(make_environ): Delete function.
	(free_environ): Delete function.
	(gdb_environ::clear): New function.
	(gdb_environ::operator=): New function.
	(gdb_environ::get): Likewise.
	(environ_vector): Delete function.
	(set_in_environ): Delete function.
	(gdb_environ::set): New function.
	(unset_in_environ): Delete function.
	(gdb_environ::unset): New function.
	(gdb_environ::envp): Likewise.
	* common/environ.h: Include <vector>.
	(struct gdb_environ): Delete; transform into...
	(class gdb_environ): ... this class.
	(free_environ): Delete prototype.
	(init_environ, get_in_environ, set_in_environ, unset_in_environ,
	environ_vector): Likewise.
	* infcmd.c (run_command_1): Update code to call
	'envp' from 'gdb_environ' class.
	(environment_info): Update code to call methods from 'gdb_environ'
	class.
	(unset_environment_command): Likewise.
	(path_info): Likewise.
	(path_command): Likewise.
	* inferior.c (inferior::~inferior): Delete call to 'free_environ'.
	(inferior::inferior): Initialize 'environment' using the host's
	information.
	* inferior.h: Remove forward declaration of 'struct gdb_environ'.
	Include "environ.h".
	(class inferior) <environment>: Change type from 'struct
	gdb_environ' to 'gdb_environ'.
	* mi/mi-cmd-env.c (mi_cmd_env_path): Update code to call
	methods from 'gdb_environ' class.
	* solib.c (solib_find_1): Likewise
	* unittests/environ-selftests.c: New file.

gdb/gdbserver/ChangeLog:
2017-06-20  Sergio Durigan Junior  <sergiodj@redhat.com>

	* linux-low.c (linux_create_inferior): Adjust code to access the
	environment information via 'gdb_environ' class.
	* lynx-low.c (lynx_create_inferior): Likewise.
	* server.c (our_environ): Make it an instance of 'gdb_environ'.
	(get_environ): Return a pointer to 'our_environ'.
	(captured_main): Initialize 'our_environ'.
	* server.h (get_environ): Adjust prototype.
	* spu-low.c (spu_create_inferior): Adjust code to access the
	environment information via 'gdb_environ' class.

6 files changed, 22 insertions, 11 deletions

diff --git a/gdb/gdbserver/ChangeLog b/gdb/gdbserver/ChangeLog
index c190fce..f9261d6 100644
--- a/gdb/gdbserver/ChangeLog
+++ b/gdb/gdbserver/ChangeLog
@@ -1,3 +1,15 @@
+2017-06-20  Sergio Durigan Junior  <sergiodj@redhat.com>
+
+	* linux-low.c (linux_create_inferior): Adjust code to access the
+	environment information via 'gdb_environ' class.
+	* lynx-low.c (lynx_create_inferior): Likewise.
+	* server.c (our_environ): Make it an instance of 'gdb_environ'.
+	(get_environ): Return a pointer to 'our_environ'.
+	(captured_main): Initialize 'our_environ'.
+	* server.h (get_environ): Adjust prototype.
+	* spu-low.c (spu_create_inferior): Adjust code to access the
+	environment information via 'gdb_environ' class.
+
 2017-06-17  Simon Marchi  <simon.marchi@ericsson.com>
 
 	* linux-low.c (linux_read_memory, linux_write_memory): Remove
diff --git a/gdb/gdbserver/linux-low.c b/gdb/gdbserver/linux-low.c
index c8e8d08..3d7cfe3 100644
--- a/gdb/gdbserver/linux-low.c
+++ b/gdb/gdbserver/linux-low.c
@@ -998,7 +998,7 @@ linux_create_inferior (const char *program,
 
   pid = fork_inferior (program,
 		       str_program_args.c_str (),
-		       environ_vector (get_environ ()), linux_ptrace_fun,
+		       get_environ ()->envp (), linux_ptrace_fun,
 		       NULL, NULL, NULL, NULL);
 
   do_cleanups (restore_personality);
diff --git a/gdb/gdbserver/lynx-low.c b/gdb/gdbserver/lynx-low.c
index 35160d6..77f570e 100644
--- a/gdb/gdbserver/lynx-low.c
+++ b/gdb/gdbserver/lynx-low.c
@@ -259,7 +259,7 @@ lynx_create_inferior (const char *program,
 
   pid = fork_inferior (program,
 		       str_program_args.c_str (),
-		       environ_vector (get_environ ()), lynx_ptrace_fun,
+		       get_environ ()->envp (), lynx_ptrace_fun,
 		       NULL, NULL, NULL, NULL);
 
   post_fork_inferior (pid, program);
diff --git a/gdb/gdbserver/server.c b/gdb/gdbserver/server.c
index 1d7a8b0..3838351 100644
--- a/gdb/gdbserver/server.c
+++ b/gdb/gdbserver/server.c
@@ -42,7 +42,7 @@
 
 /* The environment to pass to the inferior when creating it.  */
 
-struct gdb_environ *our_environ = NULL;
+static gdb_environ our_environ;
 
 /* Start the inferior using a shell.  */
 
@@ -257,10 +257,10 @@ get_exec_file (int err)
 
 /* See server.h.  */
 
-struct gdb_environ *
+gdb_environ *
 get_environ ()
 {
-  return our_environ;
+  return &our_environ;
 }
 
 static int
@@ -3698,8 +3698,7 @@ captured_main (int argc, char *argv[])
     }
 
   /* Gather information about the environment.  */
-  our_environ = make_environ ();
-  init_environ (our_environ);
+  our_environ = gdb_environ::from_host_environ ();
 
   initialize_async_io ();
   initialize_low ();
diff --git a/gdb/gdbserver/server.h b/gdb/gdbserver/server.h
index 4de4244..46b614c 100644
--- a/gdb/gdbserver/server.h
+++ b/gdb/gdbserver/server.h
@@ -62,6 +62,7 @@ int vsnprintf(char *str, size_t size, const char *format, va_list ap);
 #include "mem-break.h"
 #include "gdbthread.h"
 #include "inferiors.h"
+#include "environ.h"
 
 /* Target-specific functions */
 
@@ -154,9 +155,8 @@ extern int in_queued_stop_replies (ptid_t ptid);
    inferior and PROGRAM is its name.  */
 extern void post_fork_inferior (int pid, const char *program);
 
-/* Get the 'struct gdb_environ *' being used in the current
-   session.  */
-extern struct gdb_environ *get_environ ();
+/* Get the gdb_environ being used in the current session.  */
+extern gdb_environ *get_environ ();
 
 extern target_waitstatus last_status;
 extern ptid_t last_ptid;
diff --git a/gdb/gdbserver/spu-low.c b/gdb/gdbserver/spu-low.c
index 0f770a0..6362502 100644
--- a/gdb/gdbserver/spu-low.c
+++ b/gdb/gdbserver/spu-low.c
@@ -289,7 +289,7 @@ spu_create_inferior (const char *program,
 
   pid = fork_inferior (program,
 		       str_program_args.c_str (),
-		       environ_vector (get_environ ()), spu_ptrace_fun,
+		       get_environ ()->envp (), spu_ptrace_fun,
 		       NULL, NULL, NULL, NULL);
 
   post_fork_inferior (pid, program);