Add --chuid to gpg, gpg-card, and gpg-connect-agent.

* g10/gpg.c (oChUid): New.
(opts): Add --chuid.
(main): Implement --chuid.  Delay setting of homedir until the new
chuid is done.
* sm/gpgsm.c (main): Delay setting of homedir until the new chuid is
done.
* tools/gpg-card.c (oChUid): New.
(opts): Add --chuid.
(changeuser): New helper var.
(main): Implement --chuid.
* tools/gpg-connect-agent.c (oChUid): New.
(opts): Add --chuid.
(main): Implement --chuid.
--

Signed-off-by: Werner Koch <wk@gnupg.org>

doc/gpg-card.texi

@@ -125,6 +125,16 @@ Specify a non-default gpg binary to be used by certain commands.
 @opindex gpgsm-program
 Specify a non-default gpgsm binary to be used by certain commands.
 
+@item --chuid @var{uid}
+@opindex chuid
+Change the current user to @var{uid} which may either be a number or a
+name.  This can be used from the root account to run gpg-card for
+another user.  If @var{uid} is not the current UID a standard PATH is
+set and the envvar GNUPGHOME is unset.  To override the latter the
+option @option{--homedir} can be used.  This option has only an effect
+when used on the command line.  This option has currently no effect at
+all on Windows.
+
 @end table
 
 @mansect notes (OpenPGP)

doc/gpg.texi

@@ -3617,6 +3617,16 @@ on the configuration file.
 @c OpenPGP card while several cards are available.  This option might be
 @c removed if it turns out that nobody requires it.
 
+@item --chuid @var{uid}
+@opindex chuid
+Change the current user to @var{uid} which may either be a number or a
+name.  This can be used from the root account to run gpg for
+another user.  If @var{uid} is not the current UID a standard PATH is
+set and the envvar GNUPGHOME is unset.  To override the latter the
+option @option{--homedir} can be used.  This option has only an effect
+when used on the command line.  This option has currently no effect at
+all on Windows.
+
 @end table
 
 @c *******************************

doc/tools.texi

@@ -1330,39 +1330,6 @@ gpg-connect-agent [options] [commands]
 The following options may be used:
 
 @table @gnupgtabopt
-@item -v
-@itemx --verbose
-@opindex verbose
-Output additional information while running.
-
-@item -q
-@item --quiet
-@opindex q
-@opindex quiet
-Try to be as quiet as possible.
-
-@include opt-homedir.texi
-
-@item --agent-program @var{file}
-@opindex agent-program
-Specify the agent program to be started if none is running.  The
-default value is determined by running @command{gpgconf} with the
-option @option{--list-dirs}.  Note that the pipe symbol (@code{|}) is
-used for a regression test suite hack and may thus not be used in the
-file name.
-
-@item --dirmngr-program @var{file}
-@opindex dirmngr-program
-Specify the directory manager (keyserver client) program to be started
-if none is running.  This has only an effect if used together with the
-option @option{--dirmngr}.
-
-@item --keyboxd-program @var{file}
-@opindex keyboxd-program
-Specify the keybox daemon program to be started if none is running.
-This has only an effect if used together with the option
-@option{--keyboxd}.
-
 @item --dirmngr
 @opindex dirmngr
 Connect to a running directory manager (keyserver client) instead of
@@ -1390,6 +1357,29 @@ execute it as an Assuan server. Here is how you would run @command{gpgsm}:
 @end smallexample
 Note that you may not use options on the command line in this case.
 
+@item -v
+@itemx --verbose
+@opindex verbose
+Output additional information while running.
+
+@item -q
+@item --quiet
+@opindex q
+@opindex quiet
+Try to be as quiet as possible.
+
+@include opt-homedir.texi
+
+@item --chuid @var{uid}
+@opindex chuid
+Change the current user to @var{uid} which may either be a number or a
+name.  This can be used from the root account to run gpg-connect-agent
+for another user.  If @var{uid} is not the current UID a standard PATH
+is set and the envvar GNUPGHOME is unset.  To override the latter the
+option @option{--homedir} can be used.  This option has only an effect
+when used on the command line.  This option has currently no effect at
+all on Windows.
+
 @item --no-ext-connect
 @opindex no-ext-connect
 When using @option{-S} or @option{--exec}, @command{gpg-connect-agent}
@@ -1407,6 +1397,26 @@ In interactive mode the command line history is usually saved and
 restored to and from a file below the GnuPG home directory.  This
 option inhibits the use of that file.
 
+@item --agent-program @var{file}
+@opindex agent-program
+Specify the agent program to be started if none is running.  The
+default value is determined by running @command{gpgconf} with the
+option @option{--list-dirs}.  Note that the pipe symbol (@code{|}) is
+used for a regression test suite hack and may thus not be used in the
+file name.
+
+@item --dirmngr-program @var{file}
+@opindex dirmngr-program
+Specify the directory manager (keyserver client) program to be started
+if none is running.  This has only an effect if used together with the
+option @option{--dirmngr}.
+
+@item --keyboxd-program @var{file}
+@opindex keyboxd-program
+Specify the keybox daemon program to be started if none is running.
+This has only an effect if used together with the option
+@option{--keyboxd}.
+
 @item -r @var{file}
 @itemx --run @var{file}
 @opindex run

g10/gpg.c

@@ -437,6 +437,7 @@ enum cmd_and_opt_values
     oFullTimestrings,
     oIncludeKeyBlock,
     oNoIncludeKeyBlock,
+    oChUid,
 
     oNoop
   };
@@ -897,6 +898,7 @@ static gpgrt_opt_t opts[] = {
   ARGPARSE_s_s (oLCctype,    "lc-ctype",   "@"),
   ARGPARSE_s_s (oLCmessages, "lc-messages","@"),
   ARGPARSE_s_s (oXauthority, "xauthority", "@"),
+  ARGPARSE_s_s (oChUid,      "chuid",      "@"),
   ARGPARSE_s_n (oNoAutostart, "no-autostart", "@"),
   ARGPARSE_s_n (oUseKeyboxd,    "use-keyboxd", "@"),
   /* Options which can be used in special circumstances. They are not
@@ -2328,6 +2330,8 @@ main (int argc, char **argv)
     static int print_dane_records;
     static int print_pka_records;
     static int allow_large_chunks;
+    static const char *homedirvalue;
+    static const char *changeuser;
 
 
 #ifdef __riscos__
@@ -2413,7 +2417,6 @@ main (int argc, char **argv)
     opt.keyid_format = KF_NONE;
     opt.def_sig_expire = "0";
     opt.def_cert_expire = "0";
-    gnupg_set_homedir (NULL);
     opt.passphrase_repeat = 1;
     opt.emit_version = 0;
     opt.weak_digests = NULL;
@@ -2446,7 +2449,11 @@ main (int argc, char **argv)
             break;
 
           case oHomedir:
-            gnupg_set_homedir (pargs.r.ret_str);
+            homedirvalue = pargs.r.ret_str;
+            break;
+
+          case oChUid:
+            changeuser = pargs.r.ret_str;
             break;
 
           case oNoPermissionWarn:
@@ -2498,6 +2505,11 @@ main (int argc, char **argv)
     assuan_set_gpg_err_source (GPG_ERR_SOURCE_DEFAULT);
     setup_libassuan_logging (&opt.debug, NULL);
 
+    /* Change UID and then set the homedir.  */
+    if (changeuser && gnupg_chuid (changeuser, 0))
+      log_inc_errorcount (); /* Force later termination.  */
+    gnupg_set_homedir (homedirvalue);
+
     /* Set default options which require that malloc stuff is ready.  */
     additional_weak_digest ("MD5");
     parse_auto_key_locate (DEFAULT_AKL_LIST);
@@ -2872,6 +2884,7 @@ main (int argc, char **argv)
             opt.def_recipient_self = 0;
             break;
 	  case oHomedir: break;
+          case oChUid: break;  /* Command line only (see above).  */
 	  case oNoBatch: opt.batch = 0; break;
 
           case oWithTofuInfo: opt.with_tofu_info = 1; break;

sm/gpgsm.c

@@ -992,8 +992,10 @@ main ( int argc, char **argv)
   estream_t htmlauditfp = NULL;
   struct assuan_malloc_hooks malloc_hooks;
   int pwfd = -1;
-  const char *changeuser = NULL;
-  /*mtrace();*/
+
+  static const char *homedirvalue;
+  static const char *changeuser;
+
 
   early_system_init ();
   gnupg_reopen_std (GPGSM_NAME);
@@ -1062,7 +1064,7 @@ main ( int argc, char **argv)
           break;
 
         case oHomedir:
-          gnupg_set_homedir (pargs.r.ret_str);
+          homedirvalue = pargs.r.ret_str;
           break;
 
         case oChUid:
@@ -1096,6 +1098,11 @@ main ( int argc, char **argv)
   assuan_set_gpg_err_source (GPG_ERR_SOURCE_DEFAULT);
   setup_libassuan_logging (&opt.debug, NULL);
 
+  /* Change UID and then set homedir.  */
+  if (changeuser && gnupg_chuid (changeuser, 0))
+    log_inc_errorcount (); /* Force later termination.  */
+  gnupg_set_homedir (homedirvalue);
+
   /* Setup a default control structure for command line mode */
   memset (&ctrl, 0, sizeof ctrl);
   gpgsm_init_default_ctrl (&ctrl);
@@ -1103,9 +1110,6 @@ main ( int argc, char **argv)
   ctrl.status_fd = -1; /* No status output. */
   ctrl.autodetect_encoding = 1;
 
-  if (changeuser && gnupg_chuid (changeuser, 0))
-    log_inc_errorcount (); /* Force later termination.  */
-
   /* Set the default policy file */
   opt.policy_file = make_filename (gnupg_homedir (), "policies.txt", NULL);
 

tools/gpg-card.c

@@ -76,6 +76,7 @@ enum opt_values
 
     oNoKeyLookup,
     oNoHistory,
+    oChUid,
 
     oDummy
   };
@@ -104,6 +105,7 @@ static gpgrt_opt_t opts[] = {
                 "use --no-key-lookup for \"list\""),
   ARGPARSE_s_n (oNoHistory,"no-history",
                 "do not use the command history file"),
+  ARGPARSE_s_s (oChUid,      "chuid",      "@"),
 
   ARGPARSE_end ()
 };
@@ -125,6 +127,8 @@ struct keyinfolabel_s
 };
 typedef struct keyinfolabel_s *keyinfolabel_t;
 
+/* Helper for --chuid.  */
+static const char *changeuser;
 
 /* Limit of size of data we read from a file for certain commands.  */
 #define MAX_GET_DATA_FROM_FILE 16384
@@ -235,6 +239,8 @@ parse_arguments (gpgrt_argparse_t *pargs, gpgrt_opt_t *popts)
         case oNoKeyLookup: opt.no_key_lookup = 1; break;
         case oNoHistory:   opt.no_history = 1; break;
 
+        case oChUid:       changeuser = pargs->r.ret_str; break;
+
         default: pargs->err = 2; break;
 	}
     }
@@ -279,6 +285,9 @@ main (int argc, char **argv)
   parse_arguments (&pargs, opts);
   gpgrt_argparse (NULL, &pargs, NULL);  /* Release internal state.  */
 
+  if (changeuser && gnupg_chuid (changeuser, 0))
+    log_inc_errorcount (); /* Force later termination.  */
+
   if (log_get_errorcount (0))
     exit (2);
 

tools/gpg-connect-agent.c

@@ -71,8 +71,10 @@ enum cmd_and_opt_values
     oKeyboxd,
     oUIServer,
     oNoHistory,
-    oNoAutostart
+    oNoAutostart,
+    oChUid,
 
+    oNoop
   };
 
 
@@ -107,6 +109,7 @@ static gpgrt_opt_t opts[] = {
   ARGPARSE_s_s (oAgentProgram, "agent-program", "@"),
   ARGPARSE_s_s (oDirmngrProgram, "dirmngr-program", "@"),
   ARGPARSE_s_s (oKeyboxdProgram, "keyboxd-program", "@"),
+  ARGPARSE_s_s (oChUid,          "chuid",           "@"),
 
   ARGPARSE_end ()
 };
@@ -1187,6 +1190,9 @@ main (int argc, char **argv)
   char **cmdline_commands = NULL;
   char *historyname = NULL;
 
+  static const char *changeuser;
+
+
   early_system_init ();
   gnupg_rl_initialize ();
   gpgrt_set_strusage (my_strusage);
@@ -1233,12 +1239,16 @@ main (int argc, char **argv)
           opt.enable_varsubst = 1;
           opt.trim_leading_spaces = 1;
           break;
+        case oChUid:     changeuser = pargs.r.ret_str; break;
 
         default: pargs.err = 2; break;
 	}
     }
   gpgrt_argparse (NULL, &pargs, NULL);  /* Release internal state.  */
 
+  if (changeuser && gnupg_chuid (changeuser, 0))
+    log_inc_errorcount (); /* Force later termination.  */
+
   if (log_get_errorcount (0))
     exit (2);