common,agent,dirmngr,g10,tools: Fix split_fields API.

* common/stringhelp.h (split_fields): Use const * for the strings in
the ARRAY.
(split_fields_colon): Likewise.
* common/stringhelp.c (split_fields, split_fields_colon): Fix
the implementation.
* agent/call-scd.c, agent/command.c: Follow the change.
* common/t-stringhelp.c, dirmngr/loadswdb.c: Likewise.
* g10/call-agent.c, tools/card-call-scd.c: Likewise.
* tools/card-yubikey.c, tools/gpg-card.c: Likewise.
* tools/gpg-card.h, tools/gpg-wks-client.c: Likewise.
* tools/gpgconf-comp.c, tools/gpgconf.c: Likewise.
* tools/wks-util.c: Likewise.

--

The strings in the ARRAY don't need to be released by caller, as those
are references.  It's easier to follow the code when it's explicitly
const *.

Signed-off-by: NIIBE Yutaka <gniibe@fsij.org>

tools/card-call-scd.c

@@ -962,7 +962,7 @@ learn_status_cb (void *opaque, const char *line)
           /* The format of such a line is:
            *   KEYPAIRINFO <hexgrip> <keyref> [usage] [keytime]
            */
-          char *fields[4];
+          const char *fields[4];
           int nfields;
           const char *hexgrp, *usage;
           time_t keytime;

tools/card-yubikey.c

@@ -310,7 +310,7 @@ yk_enable_disable (struct ykapps_s *yk, struct iface_s *iface,
  * stream to output information.  This function must only be called on
  * Yubikeys. */
 gpg_error_t
-yubikey_commands (card_info_t info, estream_t fp, int argc, char *argv[])
+yubikey_commands (card_info_t info, estream_t fp, int argc, const char *argv[])
 {
   gpg_error_t err;
   enum {ykLIST, ykENABLE, ykDISABLE } cmd;

tools/gpg-card.c

@@ -2189,11 +2189,11 @@ cmd_writekey (card_info_t info, char *argstr)
 {
   gpg_error_t err;
   int opt_force;
-  char *argv[2];
+  const char *argv[2];
   int argc;
   char *keyref_buffer = NULL;
-  char *keyref;
-  char *keygrip;
+  const char *keyref;
+  const char *keygrip;
 
   if (!info)
     return print_help
@@ -3376,7 +3376,7 @@ cmd_yubikey (card_info_t info, char *argstr)
 {
   gpg_error_t err, err2;
   estream_t fp = opt.interactive? NULL : es_stdout;
-  char *words[20];
+  const char *words[20];
   int nwords;
 
   if (!info)

tools/gpg-card.h

@@ -244,7 +244,7 @@ unsigned long agent_get_s2k_count (void);
 
 /*-- card-yubikey.c --*/
 gpg_error_t yubikey_commands (card_info_t info,
-                              estream_t fp, int argc, char *argv[]);
+                              estream_t fp, int argc, const char *argv[]);
 
 
 #endif /*GNUPG_GPG_CARD_H*/

tools/gpg-wks-client.c

@@ -558,7 +558,7 @@ decrypt_stream_status_cb (void *opaque, const char *keyword, char *args)
     log_debug ("gpg status: %s %s\n", keyword, args);
   if (!strcmp (keyword, "DECRYPTION_KEY") && !decinfo->fpr)
     {
-      char *fields[3];
+      const char *fields[3];
 
       if (split_fields (args, fields, DIM (fields)) >= 3)
         {
@@ -1199,7 +1199,7 @@ static void
 encrypt_response_status_cb (void *opaque, const char *keyword, char *args)
 {
   gpg_error_t *failure = opaque;
-  char *fields[2];
+  const char *fields[2];
 
   if (DBG_CRYPTO)
     log_debug ("gpg status: %s %s\n", keyword, args);

tools/gpgconf-comp.c

@@ -1553,8 +1553,8 @@ retrieve_options_from_program (gc_component_id_t component, int only_installed)
 
   while ((length = es_read_line (outfp, &line, &line_len, NULL)) > 0)
     {
-      char *fields[4];
-      char *optname, *optdesc;
+      const char *fields[4];
+      const char *optname, *optdesc;
       unsigned int optflags;
       int short_opt;
       gc_arg_type_t arg_type;
@@ -1621,8 +1621,8 @@ retrieve_options_from_program (gc_component_id_t component, int only_installed)
                                         string_array_size,
                                         sizeof *string_array);
         }
-      string_array[string_array_used++] = optname = xstrdup (fields[0]);
-      string_array[string_array_used++] = optdesc = xstrdup (fields[3]);
+      optname = string_array[string_array_used++] = xstrdup (fields[0]);
+      optdesc = string_array[string_array_used++] = xstrdup (fields[3]);
 
       /* Create an option table which can then be supplied to
        * gpgrt_parser.  Unfortunately there is no private pointer in

tools/gpgconf.c

@@ -361,7 +361,7 @@ query_swdb (estream_t out, const char *name, const char *current_version)
   size_t length_of_line = 0;
   size_t  maxlen;
   ssize_t len;
-  char *fields[2];
+  const char *fields[2];
   char *p;
   gnupg_isotime_t filedate = {0};
   gnupg_isotime_t verified = {0};

tools/wks-util.c

@@ -953,7 +953,7 @@ install_key_from_spec_file (const char *fname)
   char *line = NULL;
   size_t linelen = 0;
   size_t maxlen = 2048;
-  char *fields[2];
+  const char *fields[2];
   unsigned int lnr = 0;
 
   if (!fname || !strcmp (fname, ""))