Reworked passing of envars to Pinentry.

10 files changed, 788 insertions, 117 deletions

diff --git a/common/ChangeLog b/common/ChangeLog
index 40faa541e..75c79c6f6 100644
--- a/common/ChangeLog
+++ b/common/ChangeLog
@@ -1,3 +1,20 @@
+2009-07-06  Werner Koch  <wk@g10code.com>
+
+	* get-passphrase.c (struct agentargs): Add SESSION_ENV and remove
+	obsolete args.
+	(gnupg_prepare_get_passphrase): Ditto.
+
+	* session-env.c, session-env.h: New.
+	* t-session-env.c: New.
+	* Makefile.am (common_sources, module_tests): Add them.
+	* asshelp.h: Include "session-env.h"
+	* asshelp.c (send_one_option): Add arg PUTENV.
+	(send_pinentry_environment): Replace most args by SESSION_ENV and
+	rewrite fucntion.
+	(start_new_gpg_agent): Likewise.
+
+	* t-exechelp.c (test_close_all_fds): Remove debug code.
+
 2009-07-01  Werner Koch  <wk@g10code.com>
 
 	* sexputil.c (get_pk_algo_from_canon_sexp): New.
diff --git a/common/Makefile.am b/common/Makefile.am
index 2ef324e18..dd3661dac 100644
--- a/common/Makefile.am
+++ b/common/Makefile.am
@@ -69,6 +69,7 @@ common_sources = \
 	pka.c pka.h \
 	http.c http.h \
 	localename.c \
+	session-env.c session-env.h \
 	helpfile.c
 
 # Sources only useful without PTH.
@@ -111,7 +112,8 @@ status-codes.h: Makefile mkstrtable.awk exstatus.awk status.h
 #
 # Module tests
 #
-module_tests = t-convert t-percent t-gettime t-sysutils t-sexputil t-exechelp
+module_tests = t-convert t-percent t-gettime t-sysutils t-sexputil t-exechelp \
+	       t-session-env
 module_maint_tests = t-helpfile t-b64
 
 t_common_ldadd = libcommon.a ../jnlib/libjnlib.a ../gl/libgnu.a \
@@ -125,6 +127,5 @@ t_helpfile_LDADD = $(t_common_ldadd)
 t_sexputil_LDADD = $(t_common_ldadd)
 t_b64_LDADD = $(t_common_ldadd)
 t_exechelp_LDADD = $(t_common_ldadd)
-
-
+t_session_env_LDADD = $(t_common_ldadd)
 
diff --git a/common/asshelp.c b/common/asshelp.c
index 6663241ae..b373baf98 100644
--- a/common/asshelp.c
+++ b/common/asshelp.c
@@ -1,5 +1,5 @@
 /* asshelp.c - Helper functions for Assuan
- * Copyright (C) 2002, 2004, 2007 Free Software Foundation, Inc.
+ * Copyright (C) 2002, 2004, 2007, 2009 Free Software Foundation, Inc.
  *
  * This file is part of GnuPG.
  *
@@ -34,10 +34,9 @@
 #include "status.h" 
 #include "asshelp.h"
 
-
 static gpg_error_t
 send_one_option (assuan_context_t ctx, gpg_err_source_t errsource,
-                 const char *name, const char *value)
+                 const char *name, const char *value, int use_putenv)
 {
   gpg_error_t err;
   char *optstr;
@@ -46,7 +45,8 @@ send_one_option (assuan_context_t ctx, gpg_err_source_t errsource,
 
   if (!value || !*value)
     err = 0;  /* Avoid sending empty strings.  */
-  else if (asprintf (&optstr, "OPTION %s=%s", name, value ) < 0)
+  else if (asprintf (&optstr, "OPTION %s%s=%s", 
+                     use_putenv? "putenv=":"", name, value) < 0)
     err = gpg_error_from_syserror ();
   else
     {
@@ -64,57 +64,43 @@ send_one_option (assuan_context_t ctx, gpg_err_source_t errsource,
 gpg_error_t
 send_pinentry_environment (assuan_context_t ctx,
                            gpg_err_source_t errsource,
-                           const char *opt_display,
-                           const char *opt_ttyname,
-                           const char *opt_ttytype,
                            const char *opt_lc_ctype,
                            const char *opt_lc_messages,
-                           const char *opt_xauthority,
-                           const char *opt_pinentry_user_data)
+                           session_env_t session_env)
+
 {
   gpg_error_t err = 0;
-  char *dft_display = NULL;
-  char *dft_ttyname = NULL;
-  char *dft_ttytype = NULL;
   char *old_lc = NULL; 
   char *dft_lc = NULL;
-  char *dft_xauthority = NULL;
-  char *dft_pinentry_user_data = NULL;
+  const char *dft_ttyname;
+  int iterator;
+  const char *name, *assname, *value;
+  int is_default;
 
-  /* Send the DISPLAY variable.  */
-  dft_display = getenv ("DISPLAY");
-  if (opt_display || dft_display)
+  iterator = 0; 
+  while ((name = session_env_list_stdenvnames (&iterator, &assname)))
     {
-      err = send_one_option (ctx, errsource, "display", 
-                             opt_display ? opt_display : dft_display);
-      if (err)
-        return err;
-    }
+      value = session_env_getenv_or_default (session_env, name, NULL);
+      if (!value)
+        continue;
 
-  /* Send the name of the TTY.  */
-  if (!opt_ttyname)
-    {
-      dft_ttyname = getenv ("GPG_TTY");
-      if ((!dft_ttyname || !*dft_ttyname) && ttyname (0))
-        dft_ttyname = ttyname (0);
-    }
-  if (opt_ttyname || dft_ttyname)
-    {
-      err = send_one_option (ctx, errsource, "ttyname", 
-                             opt_ttyname ? opt_ttyname : dft_ttyname);
+      if (assname)
+        err = send_one_option (ctx, errsource, assname, value, 0);
+      else
+        {
+          err = send_one_option (ctx, errsource, name, value, 1);
+          if (gpg_err_code (err) == GPG_ERR_UNKNOWN_OPTION)
+            err = 0;  /* Server too old; can't pass the new envvars.  */
+        }
       if (err)
         return err;
     }
 
-  /* Send the type of the TTY.  */
-  dft_ttytype = getenv ("TERM");
-  if (opt_ttytype || (dft_ttyname && dft_ttytype))
-    {
-      err = send_one_option (ctx, errsource, "ttytype", 
-                             opt_ttyname ? opt_ttytype : dft_ttytype);
-      if (err)
-        return err;
-    }
+
+  dft_ttyname = session_env_getenv_or_default (session_env, "GPG_TTY", 
+                                               &is_default);
+  if (dft_ttyname && !is_default)
+    dft_ttyname = NULL;  /* We need the default value.  */
 
   /* Send the value for LC_CTYPE.  */
 #if defined(HAVE_SETLOCALE) && defined(LC_CTYPE)
@@ -130,7 +116,7 @@ send_pinentry_environment (assuan_context_t ctx,
   if (opt_lc_ctype || (dft_ttyname && dft_lc))
     {
       err = send_one_option (ctx, errsource, "lc-ctype", 
-                             opt_lc_ctype ? opt_lc_ctype : dft_lc);
+                             opt_lc_ctype ? opt_lc_ctype : dft_lc, 0);
     }
 #if defined(HAVE_SETLOCALE) && defined(LC_CTYPE)
   if (old_lc)
@@ -156,7 +142,7 @@ send_pinentry_environment (assuan_context_t ctx,
   if (opt_lc_messages || (dft_ttyname && dft_lc))
     {
       err = send_one_option (ctx, errsource, "lc-messages", 
-                             opt_lc_messages ? opt_lc_messages : dft_lc);
+                             opt_lc_messages ? opt_lc_messages : dft_lc, 0);
     }
 #if defined(HAVE_SETLOCALE) && defined(LC_MESSAGES)
   if (old_lc)
@@ -168,31 +154,6 @@ send_pinentry_environment (assuan_context_t ctx,
   if (err)
     return err;
 
-  /* Send the XAUTHORITY variable.  */
-  dft_xauthority = getenv ("XAUTHORITY");
-  if (opt_xauthority || dft_xauthority)
-    {
-      err = send_one_option (ctx, errsource, "xauthority", 
-                             opt_xauthority ? opt_xauthority : dft_xauthority);
-      if (gpg_err_code (err) == GPG_ERR_UNKNOWN_OPTION)
-        err = 0;
-      if (err)
-        return err;
-    }
-
-  /* Send the PINENTRY_USER_DATA variable.  */
-  dft_pinentry_user_data = getenv ("PINENTRY_USER_DATA");
-  if (opt_pinentry_user_data || dft_pinentry_user_data)
-    {
-      err = send_one_option (ctx, errsource, "pinentry-user-data", 
-                             opt_pinentry_user_data ?
-                             opt_pinentry_user_data : dft_pinentry_user_data);
-      if (gpg_err_code (err) == GPG_ERR_UNKNOWN_OPTION)
-        err = 0;
-      if (err)
-        return err;
-    }
-
   return 0;
 }
 
@@ -205,13 +166,9 @@ start_new_gpg_agent (assuan_context_t *r_ctx,
                      gpg_err_source_t errsource,
                      const char *homedir,
                      const char *agent_program,
-                     const char *opt_display,
-                     const char *opt_ttyname,
-                     const char *opt_ttytype,
                      const char *opt_lc_ctype,
                      const char *opt_lc_messages,
-                     const char *opt_xauthority,
-                     const char *opt_pinentry_user_data,
+                     session_env_t session_env,
                      int verbose, int debug,
                      gpg_error_t (*status_cb)(ctrl_t, int, ...),
                      ctrl_t status_cb_arg)
@@ -365,10 +322,8 @@ start_new_gpg_agent (assuan_context_t *r_ctx,
                         NULL, NULL, NULL, NULL, NULL, NULL);
   if (!rc)
     rc = send_pinentry_environment (ctx, errsource,
-                                    opt_display, opt_ttyname, opt_ttytype,
                                     opt_lc_ctype, opt_lc_messages,
-                                    opt_xauthority,
-                                    opt_pinentry_user_data);
+                                    session_env);
   if (rc)
     {
       assuan_disconnect (ctx);
diff --git a/common/asshelp.h b/common/asshelp.h
index dfed3ac50..f7bc88bad 100644
--- a/common/asshelp.h
+++ b/common/asshelp.h
@@ -23,31 +23,25 @@
 #include <assuan.h>
 #include <gpg-error.h>
 
+#include "session-env.h"
+
 gpg_error_t
 send_pinentry_environment (assuan_context_t ctx,
                            gpg_err_source_t errsource,
-                           const char *opt_display,
-                           const char *opt_ttyname,
-                           const char *opt_ttytype,
                            const char *opt_lc_ctype,
                            const char *opt_lc_messages,
-                           const char *opt_xauthority,
-                           const char *opt_pinentry_user_data);
+                           session_env_t session_env);
 
 /* This fucntion is used by the call-agent.c modules to fire up a new
-   agent.  What a parameter list ;-).  */
+   agent.  */
 gpg_error_t
 start_new_gpg_agent (assuan_context_t *r_ctx,
                      gpg_err_source_t errsource,
                      const char *homedir,
                      const char *agent_program,
-                     const char *opt_display,
-                     const char *opt_ttyname,
-                     const char *opt_ttytype,
                      const char *opt_lc_ctype,
                      const char *opt_lc_messages,
-                     const char *opt_xauthority,
-                     const char *opt_pinentry_user_data,
+                     session_env_t session_env,
                      int verbose, int debug,
                      gpg_error_t (*status_cb)(ctrl_t, int, ...),
                      ctrl_t status_cb_arg);
diff --git a/common/get-passphrase.c b/common/get-passphrase.c
index 68d7b706a..e1a11482e 100644
--- a/common/get-passphrase.c
+++ b/common/get-passphrase.c
@@ -39,12 +39,9 @@ static struct
   int verbosity;
   const char *homedir;
   const char *agent_program;
-  const char *display;
-  const char *ttyname;
-  const char *ttytype;
   const char *lc_ctype;
   const char *lc_messages;
-  const char *xauthority;
+  session_env_t session_env;
   const char *pinentry_user_data;
 } agentargs;
 
@@ -57,25 +54,17 @@ gnupg_prepare_get_passphrase (gpg_err_source_t errsource,
                               int verbosity,
                               const char *homedir,
                               const char *agent_program,
-                              const char *opt_display,
-                              const char *opt_ttyname,
-                              const char *opt_ttytype,
                               const char *opt_lc_ctype,
                               const char *opt_lc_messages,
-                              const char *opt_xauthority,
-                              const char *opt_pinentry_user_data)
+                              session_env_t session_env)
 {
   agentargs.errsource          = errsource;
   agentargs.verbosity          = verbosity;
   agentargs.homedir            = homedir;
   agentargs.agent_program      = agent_program;
-  agentargs.display            = opt_display;
-  agentargs.ttyname            = opt_ttyname;
-  agentargs.ttytype            = opt_ttytype;
   agentargs.lc_ctype           = opt_lc_ctype;
   agentargs.lc_messages        = opt_lc_messages;
-  agentargs.xauthority         = opt_xauthority;
-  agentargs.pinentry_user_data = opt_pinentry_user_data;
+  agentargs.session_env        = session_env;
 }
 
 
@@ -96,13 +85,9 @@ start_agent (void)
                              agentargs.errsource,
                              agentargs.homedir,
                              agentargs.agent_program,
-                             agentargs.display, 
-                             agentargs.ttyname,
-                             agentargs.ttytype,
                              agentargs.lc_ctype,
                              agentargs.lc_messages,
-                             agentargs.xauthority,
-                             agentargs.pinentry_user_data,
+                             agentargs.session_env,
                              agentargs.verbosity, 0, NULL, NULL);
   if (!err)
     {
diff --git a/common/get-passphrase.h b/common/get-passphrase.h
index 9457cdd3a..603ac81b9 100644
--- a/common/get-passphrase.h
+++ b/common/get-passphrase.h
@@ -20,17 +20,15 @@
 #ifndef GNUPG_COMMON_GET_PASSPHRASE_H
 #define GNUPG_COMMON_GET_PASSPHRASE_H
 
+#include "session-env.h"
+
 void gnupg_prepare_get_passphrase (gpg_err_source_t errsource,
                                    int verbosity,
                                    const char *homedir,
                                    const char *agent_program,
-                                   const char *opt_display,
-                                   const char *opt_ttyname,
-                                   const char *opt_ttytype,
                                    const char *opt_lc_ctype,
                                    const char *opt_lc_messages,
-                                   const char *opt_xauthority,
-                                   const char *opt_pinentry_user_data);
+                                   session_env_t session_env);
 
 gpg_error_t gnupg_get_passphrase (const char *cache_id,
                                   const char *err_msg,
diff --git a/common/session-env.c b/common/session-env.c
new file mode 100644
index 000000000..ef36dbcbf
--- /dev/null
+++ b/common/session-env.c
@@ -0,0 +1,384 @@
+/* se4ssiobn-env.c - session environment helper functions.
+ * Copyright (C) 2009 Free Software Foundation, Inc.
+ *
+ * This file is part of GnuPG.
+ *
+ * GnuPG is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * GnuPG is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <config.h>
+#include <stdlib.h>
+#include <errno.h>
+#include <ctype.h>
+#include <assert.h>
+#include <unistd.h>
+
+#include "util.h"
+#include "session-env.h"
+
+
+struct variable_s
+{
+  char *value;    /* Pointer into NAME to the Nul terminated value. */
+  int is_default; /* The value is a default one.  */
+  char name[1];   /* Nul terminated Name and space for the value.  */
+};
+
+
+
+/* The session environment object.  */
+struct session_environment_s
+{
+  size_t arraysize;          /* Allocated size or ARRAY.  */
+  size_t arrayused;          /* Used size of ARRAY.  */
+  struct variable_s **array; /* Array of variables.  NULL slots are unused.  */
+};
+
+
+/* A list of environment vribales we pass from the acual user
+  (e.g. gpgme) down to the pinentry.  We do not handle the locale
+  settings because they do not only depend on envvars.  */
+static struct 
+{ 
+  const char *name;
+  const char *assname;  /* Name used by Assuan or NULL.  */
+} stdenvnames[] = {
+  { "GPG_TTY", "ttyname" },      /* GnuPG specific envvar.  */
+  { "TERM",    "ttytype" },      /* Used to set ttytype. */
+  { "DISPLAY", "display" },      /* The X-Display.  */
+  { "XAUTHORITY","xauthority"},  /* Xlib Authentication.  */
+  { "XMODIFIERS" },              /* Used by Xlib to select X input
+                                      modules (eg "@im=SCIM").  */
+  { "GTK_IM_MODULE" },           /* Used by gtk to select gtk input
+                                    modules (eg "scim-bridge").  */
+  { "QT_IM_MODULE" },            /* Used by Qt to select qt input
+                                      modules (eg "xim").  */
+  { "PINENTRY_USER_DATA", "pinentry-user-data"} 
+                                 /* Used for communication with
+                                    non-standard Pinentries.  */
+};
+
+
+/* Track last allocated arraysize of all objects ever created.  If
+   nothing has ever been allocated we use INITIAL_ARRAYSIZE and we
+   will never use more than MAXDEFAULT_ARRAYSIZE for initial
+   allocation.  Note that this is not reentrant if used with a
+   preemptive thread model.  */
+static size_t lastallocatedarraysize;
+#define INITIAL_ARRAYSIZE 8  /* Let's use the number of stdenvnames.  */
+#define CHUNK_ARRAYSIZE 10
+#define MAXDEFAULT_ARRAYSIZE (INITIAL_ARRAYSIZE + CHUNK_ARRAYSIZE * 5)
+
+
+/* Return the names of standard environment variables one after the
+   other.  The caller needs to set the value at the address of
+   ITERATOR initally to 0 and then call this function until it returns
+   NULL.  */
+const char *
+session_env_list_stdenvnames (int *iterator, const char **r_assname)
+{
+  int idx = *iterator;
+
+  if (idx < 0 || idx >= DIM (stdenvnames))
+    return NULL;
+  *iterator = idx + 1;
+  if (r_assname)
+    *r_assname = stdenvnames[idx].assname;
+  return stdenvnames[idx].name;
+}
+
+
+/* Create a new session environment object.  Return NULL and sets
+   ERRNO on failure. */
+session_env_t
+session_env_new (void)
+{
+  session_env_t se;
+
+  se = xtrycalloc (1, sizeof *se);
+  if (se)
+    {
+      se->arraysize = (lastallocatedarraysize? 
+                       lastallocatedarraysize : INITIAL_ARRAYSIZE);
+      se->array = xtrycalloc (se->arraysize, sizeof *se->array);
+      if (!se->array)
+        {
+          xfree (se);
+          se = NULL;
+        }
+    }
+
+  return se;
+}
+
+
+/* Release a session environment object.  */
+void
+session_env_release (session_env_t se)
+{
+  int idx;
+
+  if (!se)
+    return;
+
+  if (se->arraysize > INITIAL_ARRAYSIZE 
+      && se->arraysize <= MAXDEFAULT_ARRAYSIZE
+      && se->arraysize > lastallocatedarraysize)
+    lastallocatedarraysize = se->arraysize;
+
+  for (idx=0; idx < se->arrayused; idx++)
+    if (se->array[idx])
+      xfree (se->array[idx]);
+  xfree (se->array);
+  xfree (se);
+}
+
+
+static gpg_error_t
+delete_var (session_env_t se, const char *name)
+{
+  int idx;
+
+  for (idx=0; idx < se->arrayused; idx++)
+    if (se->array[idx] && !strcmp (se->array[idx]->name, name))
+      {
+        xfree (se->array[idx]);
+        se->array[idx] = NULL;
+      }
+  return 0;
+}
+
+
+static gpg_error_t
+update_var (session_env_t se, const char *string, size_t namelen,
+            const char *explicit_value, int set_default)
+{
+  int idx;
+  int freeidx = -1;
+  const char *value;
+  size_t valuelen;
+  struct variable_s *var;
+
+  if (explicit_value)
+    value = explicit_value;
+  else
+    value = string + namelen + 1;
+  valuelen = strlen (value);
+
+  for (idx=0; idx < se->arrayused; idx++)
+    {
+      if (!se->array[idx])
+        freeidx = idx;
+      else if (!strncmp (se->array[idx]->name, string, namelen)
+               && strlen (se->array[idx]->name) == namelen)
+        {
+          /* Check if the value is the same; no need to update it,
+             except for updating the default flag.  */
+          if (strlen (se->array[idx]->value) == valuelen)
+            {
+              se->array[idx]->is_default = !!set_default;
+              return 0;
+            }
+          /* Prepare for update.  */
+          freeidx = idx;
+        }
+    }
+
+  if (freeidx == -1)
+    {
+      if (se->arrayused == se->arraysize)
+        {
+          /* Reallocate the array. */
+          size_t newsize;
+          struct variable_s **newarray;
+
+          newsize = se->arraysize + CHUNK_ARRAYSIZE;
+          newarray = xtrycalloc (newsize, sizeof *newarray);
+          if (!newarray)
+            return gpg_error_from_syserror ();
+          for (idx=0; idx < se->arrayused; idx++)
+            newarray[idx] = se->array[idx];
+          se->arraysize = newsize;
+          xfree (se->array);
+          se->array = newarray;
+        }
+      freeidx = se->arrayused++;
+    }
+
+  /* Allocate new memory and return an error if that didn't worked.
+     Allocating it first allows us to keep the old value; it doesn't
+     matter that arrayused has already been incremented in case of a
+     new entry - it will then pint to a NULL slot.  */
+  var = xtrymalloc (sizeof *var + namelen + 1 + valuelen);
+  if (!var)
+    return gpg_error_from_syserror ();
+  var->is_default = !!set_default;
+  memcpy (var->name, string, namelen);
+  var->name[namelen] = '\0';
+  var->value = var->name + namelen + 1;
+  strcpy (var->value, value);
+
+  xfree (se->array[freeidx]);
+  se->array[freeidx] = var;
+  return 0;
+}
+
+
+/* Set or update an environment variable of the session environment.
+   String is similar to the putval(3) function but it is reentrant and
+   takes a copy.  In particular it exhibits this behaviour:
+
+          <NAME>            Delete envvar NAME
+          <KEY>=            Set envvar NAME to the empty string
+          <KEY>=<VALUE>     Set envvar NAME to VALUE
+
+   On success 0 is returned; on error an gpg-error code.  */
+gpg_error_t
+session_env_putenv (session_env_t se, const char *string)
+{
+  const char *s;
+  
+  if (!string || !*string)
+    return gpg_error (GPG_ERR_INV_VALUE);
+  s = strchr (string, '=');
+  if (s == string)
+    return gpg_error (GPG_ERR_INV_VALUE);
+  if (!s)
+    return delete_var (se, string);
+  else
+    return update_var (se, string, s - string, NULL, 0);
+}
+
+
+/* Same as session_env_putenv but with name and value given as distict
+   values.  */
+gpg_error_t
+session_env_setenv (session_env_t se, const char *name, const char *value)
+{
+  if (!name || !*name)
+    return gpg_error (GPG_ERR_INV_VALUE);
+  if (!value)
+    return delete_var (se, name);
+  else
+    return update_var (se, name, strlen (name), value, 0);
+}
+
+
+
+
+/* Return the value of the environment variable NAME from the SE
+   object.  If the variable does not exist, NULL is returned.  The
+   returned value is valid as long as SE is valid and as long it has
+   not been removed or updated by a call to session_env_putenv.  The
+   caller MUST not change the returned value. */
+char *
+session_env_getenv (session_env_t se, const char *name)
+{
+  int idx;
+
+  if (!se || !name || !*name)
+    return NULL;
+
+  for (idx=0; idx < se->arrayused; idx++)
+    if (se->array[idx] && !strcmp (se->array[idx]->name, name))
+      return se->array[idx]->is_default? NULL : se->array[idx]->value;
+  return NULL;
+}
+
+
+/* Return the value of the environment variable NAME from the SE
+   object.  The returned value is valid as long as SE is valid and as
+   long it has not been removed or updated by a call to
+   session_env_putenv.  If the variable does not exist, the fucntion
+   tries to return the value trough a call to getenv; if that returns
+   a value, this value is recorded and and used.  If no value could be
+   found, returns NULL.  The caller must not change the returned
+   value. */
+char *
+session_env_getenv_or_default (session_env_t se, const char *name,
+                               int *r_default)
+{
+  int idx;
+  char *defvalue;
+
+  if (r_default)
+    *r_default = 0;
+  if (!se || !name || !*name)
+    return NULL;
+
+  for (idx=0; idx < se->arrayused; idx++)
+    if (se->array[idx] && !strcmp (se->array[idx]->name, name))
+      {
+        if (r_default && se->array[idx]->is_default)
+          *r_default = 1;
+        return se->array[idx]->value;
+      }
+  
+  /* Get the default value with and additional fallback for GPG_TTY.  */
+  defvalue = getenv (name);
+  if ((!defvalue || !*defvalue) && !strcmp (name, "GPG_TTY") && ttyname (0))
+    defvalue = ttyname (0);
+  if (defvalue)
+    {
+      /* Record the default value for later use so that we are safe
+         from later modifications of the environment.  We need to take
+         a copy to better cope with the rules of putenv(3).  We ignore
+         the error of the update function because we can't return an
+         explicit error anyway and the following scan would then fail
+         anyway. */
+      update_var (se, name, strlen (name), defvalue, 1);
+      
+      for (idx=0; idx < se->arrayused; idx++)
+        if (se->array[idx] && !strcmp (se->array[idx]->name, name))
+          {
+            if (r_default && se->array[idx]->is_default)
+              *r_default = 1;
+            return se->array[idx]->value;
+          }
+    }
+
+  return NULL;
+}
+
+
+/* List the entire environment stored in SE.  The caller initially
+   needs to set the value of ITERATOR to 0 and then call this function
+   until it returns NULL.  The value is retruned at R_VALUE.  If
+   R_DEFAULT is not NULL, the default flag is stored on return.  The
+   default flag indicates that the value has been taken from the
+   process' environment.  The caller must not change the returned
+   name or value.  */ 
+char *
+session_env_listenv (session_env_t se, int *iterator,
+                     const char **r_value, int *r_default)
+{
+  int idx = *iterator;
+
+  if (!se || idx < 0)
+    return NULL;
+
+  for (; idx < se->arrayused; idx++)
+    if (se->array[idx])
+      {
+        *iterator = idx+1;
+        if (r_default)
+          *r_default = se->array[idx]->is_default;
+        if (r_value)
+          *r_value = se->array[idx]->value;
+        return se->array[idx]->name;
+      }
+  return NULL;
+}
+
+
diff --git a/common/session-env.h b/common/session-env.h
new file mode 100644
index 000000000..031fe1d7c
--- /dev/null
+++ b/common/session-env.h
@@ -0,0 +1,43 @@
+/* session-env.h - Definitions for session environment functions
+ * Copyright (C) 2009 Free Software Foundation, Inc.
+ *
+ * This file is part of GnuPG.
+ *
+ * GnuPG is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * GnuPG is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef GNUPG_COMMON_SESSION_ENV_H
+#define GNUPG_COMMON_SESSION_ENV_H
+
+struct session_environment_s;
+typedef struct session_environment_s *session_env_t;
+
+const char *session_env_list_stdenvnames (int *iterator, 
+                                          const char **r_assname);
+
+session_env_t session_env_new (void);
+void session_env_release (session_env_t se);
+
+gpg_error_t session_env_putenv (session_env_t se, const char *string);
+gpg_error_t session_env_setenv (session_env_t se, 
+                                const char *name, const char *value);
+
+char *session_env_getenv (session_env_t se, const char *name);
+char *session_env_getenv_or_default (session_env_t se, const char *name,
+                                     int *r_default);
+char *session_env_listenv (session_env_t se, int *iterator, 
+                           const char **r_value, int *r_default);
+
+
+#endif /*GNUPG_COMMON_SESSION_ENV_H*/
diff --git a/common/t-exechelp.c b/common/t-exechelp.c
index 7ab6bbe0a..600379b69 100644
--- a/common/t-exechelp.c
+++ b/common/t-exechelp.c
@@ -69,7 +69,7 @@ xget_all_open_fds (void)
 
 /* That is a very crude test.  To do a proper test we would need to
    fork a test process and best return information by some other means
-   that file descriptors. */
+   than file descriptors. */
 static void
 test_close_all_fds (void)
 {
@@ -77,7 +77,7 @@ test_close_all_fds (void)
   int *array;
   int fd;
   int initial_count, count, n;
-#if 1
+#if 0
   char buffer[100];
 
   snprintf (buffer, sizeof buffer, "/bin/ls -l /proc/%d/fd", (int)getpid ());
diff --git a/common/t-session-env.c b/common/t-session-env.c
new file mode 100644
index 000000000..94b668328
--- /dev/null
+++ b/common/t-session-env.c
@@ -0,0 +1,294 @@
+/* t-session-env.c - Module test for session-env.c
+ *	Copyright (C) 2009 Free Software Foundation, Inc.
+ *
+ * This file is part of GnuPG.
+ *
+ * GnuPG is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * GnuPG is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <config.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <errno.h>
+#include <assert.h>
+
+#include "util.h"
+#include "session-env.h"
+
+#define pass()  do { ; } while(0)
+#define fail(e) do { fprintf (stderr, "%s:%d: function failed: %s\n",  \
+                               __FILE__,__LINE__, gpg_strerror (e));  \
+                     exit (1);                                        \
+                   } while(0)
+
+static int verbose;
+
+static void
+listall (session_env_t se)
+{
+  int iterator = 0;
+  const char *name, *value;
+  int def;
+
+  if (verbose)
+    printf ("environment of %p\n", se);
+  while ( (name = session_env_listenv (se, &iterator, &value, &def)) )
+    if (verbose)
+      printf ("  %s%s=%s\n",  def? "[def] ":"      ", name, value);
+          
+}
+
+
+static void
+show_stdnames (void)
+{
+  const char *name, *assname;
+  int iterator = 0;
+
+  printf ("Known envvars:");
+  while ((name = session_env_list_stdenvnames (&iterator, &assname)))
+    {
+      printf ( " %s", name);
+      if (assname)
+        printf ( "(%s)", assname);
+    }
+  putchar('\n');
+}
+
+
+static void
+test_all (void)
+{
+  gpg_error_t err;
+  session_env_t se_0, se;
+  const char *s, *s2;
+  int idx;
+
+  se_0 = session_env_new ();
+  if (!se_0)
+    fail (gpg_error_from_syserror ());
+  se = session_env_new ();
+  if (!se)
+    fail (gpg_error_from_syserror ());
+
+  err = session_env_putenv (se, NULL);
+  if (gpg_err_code (err) != GPG_ERR_INV_VALUE)
+    fail (err);
+  err = session_env_putenv (se, "");
+  if (gpg_err_code (err) != GPG_ERR_INV_VALUE)
+    fail (err);
+  err = session_env_putenv (se, "=");
+  if (gpg_err_code (err) != GPG_ERR_INV_VALUE)
+    fail (err);
+
+  /* Delete some nonexistant variables.  */
+  err = session_env_putenv (se, "A");
+  if (err)
+    fail (err);
+  err = session_env_putenv (se, "a");
+  if (err)
+    fail (err);
+  err = session_env_putenv (se, "_aaaa aaaaaasssssssssssss\nddd");
+  if (err)
+    fail (err);
+
+  /* Create a few variables.  */
+  err = session_env_putenv (se, "EMPTY=");
+  if (err)
+    fail (err);
+  err = session_env_putenv (se, "foo=value_of_foo");
+  if (err)
+    fail (err);
+  err = session_env_putenv (se, "bar=the value_of_bar");
+  if (err)
+    fail (err);
+  err = session_env_putenv (se, "baz=this-is-baz");
+  if (err)
+    fail (err);
+  err = session_env_putenv (se, "BAZ=this-is-big-baz");
+  if (err)
+    fail (err);
+
+  listall (se);
+
+  /* Update one.  */
+  err = session_env_putenv (se, "baz=this-is-another-baz");
+  if (err)
+    fail (err);
+
+  listall (se);
+
+  /* Delete one.  */
+  err = session_env_putenv (se, "bar");
+  if (err)
+    fail (err);
+
+  listall (se);
+
+  /* Insert a new one.  */
+  err = session_env_putenv (se, "FOO=value_of_foo");
+  if (err)
+    fail (err);
+
+  listall (se);
+
+  /* Retrieve a default one.  */
+  s = session_env_getenv_or_default (se, "HOME", NULL);
+  if (!s)
+    {
+      fprintf (stderr, "failed to get default of HOME\n");
+      exit (1);
+    }
+      
+  s = session_env_getenv (se, "HOME");
+  if (s)
+    fail(0);  /* This is a default value, thus we should not see it.  */
+
+  s = session_env_getenv_or_default (se, "HOME", NULL);
+  if (!s)
+    fail(0);  /* But here we should see it.  */
+
+  /* Add a few more.  */
+  err = session_env_putenv (se, "X1=A value");
+  if (err)
+    fail (err);
+  err = session_env_putenv (se, "X2=Another value");
+  if (err)
+    fail (err);
+  err = session_env_putenv (se, "X3=A value");
+  if (err)
+    fail (err);
+
+  listall (se);
+
+  /* Check that we can overwrite a default value.  */
+  err = session_env_putenv (se, "HOME=/this/is/my/new/home");
+  if (err)
+    fail (err);
+  /* And that we get this string back.  */
+  s = session_env_getenv (se, "HOME");
+  if (!s)
+    fail (0);
+  if (strcmp (s, "/this/is/my/new/home"))
+    fail (0);
+  /* A new get default should return the very same string.  */
+  s2 = session_env_getenv_or_default (se, "HOME", NULL);
+  if (!s2)
+    fail (0);
+  if (s2 != s)
+    fail (0);
+
+  listall (se);
+
+  /* Check that the other object is clean.  */
+  {
+    int iterator = 0;
+    
+    if (session_env_listenv (se_0, &iterator, NULL, NULL))
+      fail (0);
+  }
+
+
+  session_env_release (se);
+
+  /* Use a new session for quick mass test.  */
+  se = session_env_new ();
+  if (!se)
+    fail (gpg_error_from_syserror ());
+
+  /* Create.  */
+  for (idx=0; idx < 500; idx++)
+    {
+      char buf[100];
+      
+      snprintf (buf, sizeof buf, "FOO_%d=Value for %x", idx, idx);
+      err = session_env_putenv (se, buf);
+      if (err)
+        fail (err);
+    }
+  err = session_env_setenv (se, "TEST1", "value1");
+  if (err)
+    fail (err);
+  err = session_env_setenv (se, "TEST1", "value1-updated");
+  if (err)
+    fail (err);
+
+  listall (se);
+
+  /* Delete all.  */
+  for (idx=0; idx < 500; idx++)
+    {
+      char buf[100];
+      
+      snprintf (buf, sizeof buf, "FOO_%d", idx);
+      err = session_env_putenv (se, buf);
+      if (err)
+        fail (err);
+    }
+  err = session_env_setenv (se, "TEST1", NULL);
+  if (err)
+    fail (err);
+
+  /* Check that all are deleted.  */
+  {
+    int iterator = 0;
+    
+    if (session_env_listenv (se, &iterator, NULL, NULL))
+      fail (0);
+  }
+
+  /* Add a few strings again.  */
+  for (idx=0; idx < 500; idx++)
+    {
+      char buf[100];
+      
+      if (!(idx % 10))
+        {
+          if ( !(idx % 3))
+            snprintf (buf, sizeof buf, "FOO_%d=", idx);
+          else
+            snprintf (buf, sizeof buf, "FOO_%d=new value for %x", idx, idx);
+          err = session_env_putenv (se, buf);
+          if (err)
+            fail (err);
+        }
+    }
+
+  listall (se);
+  
+  session_env_release (se);
+
+  session_env_release (se_0);
+}
+
+
+
+int
+main (int argc, char **argv)
+{
+  if (argc)
+    { argc--; argv++; }
+  if (argc && !strcmp (argv[0], "--verbose"))
+    {
+      verbose = 1;
+      argc--; argv++;
+    }
+
+
+  show_stdnames ();
+  test_all ();
+
+  return 0;
+}
+