gpg: New option --compatibility-flags

* g10/gpg.c (oCompatibilityFlags): New.
(opts): Add option.
(compatibility_flags): New list.
(main): Set flags and print help.
* g10/options.h (opt): Add field compatibility_flags.
--

No flags are yet defined but it is good to have the framework.

doc/gpg.texi

@@ -2997,6 +2997,14 @@ therefore enables a fast listing of the encryption keys.
 @opindex interactive
 Prompt before overwriting any files.
 
+@item --compatibility-flags @var{flags}
+@opindex compatibility-flags
+Set compatibility flags to work around problems due to non-compliant
+keys or data.  The @var{flags} are given as a comma separated
+list of flag names and are OR-ed together.  The special flag "none"
+clears the list and allows to start over with an empty list.  To get a
+list of available flags the sole word "help" can be used.
+
 @item --debug-level @var{level}
 @opindex debug-level
 Select the debug level for investigating problems. @var{level} may be

g10/gpg.c

@@ -444,6 +444,7 @@ enum cmd_and_opt_values
     oForceSignKey,
     oForbidGenKey,
     oRequireCompliance,
+    oCompatibilityFlags,
 
     oNoop
   };
@@ -914,6 +915,7 @@ static gpgrt_opt_t opts[] = {
   ARGPARSE_s_n (oUseKeyboxd,    "use-keyboxd", "@"),
   ARGPARSE_s_n (oForbidGenKey,  "forbid-gen-key", "@"),
   ARGPARSE_s_n (oRequireCompliance, "require-compliance", "@"),
+  ARGPARSE_s_s (oCompatibilityFlags, "compatibility-flags", "@"),
   /* Options which can be used in special circumstances. They are not
    * published and we hope they are never required.  */
   ARGPARSE_s_n (oUseOnlyOpenPGPCard, "use-only-openpgp-card", "@"),
@@ -1009,6 +1011,13 @@ static struct debug_flags_s debug_flags [] =
   };
 
 
+/* The list of compatibility flags.  */
+static struct compatibility_flags_s compatibility_flags [] =
+  {
+    { 0, NULL }
+  };
+
+
 #ifdef ENABLE_SELINUX_HACKS
 #define ALWAYS_ADD_KEYRINGS 1
 #else
@@ -2861,6 +2870,15 @@ main (int argc, char **argv)
             allow_large_chunks = 1;
             break;
 
+          case oCompatibilityFlags:
+            if (parse_compatibility_flags (pargs.r.ret_str, &opt.compat_flags,
+                                           compatibility_flags))
+              {
+                pargs.r_opt = ARGPARSE_INVALID_ARG;
+                pargs.err = ARGPARSE_PRINT_ERROR;
+              }
+            break;
+
 	  case oStatusFD:
             set_status_fd ( translate_sys2libc_fd_int (pargs.r.ret_int, 1) );
             break;
@@ -3920,6 +3938,8 @@ main (int argc, char **argv)
       }
 
     set_debug (debug_level);
+    if (opt.verbose) /* Print the compatibility flags.  */
+      parse_compatibility_flags (NULL, &opt.compat_flags, compatibility_flags);
     gnupg_set_compliance_extra_info (opt.min_rsa_length);
     if (DBG_CLOCK)
       log_clock ("start");

g10/options.h

@@ -308,6 +308,9 @@ struct
   int no_symkey_cache;   /* Disable the cache used for --symmetric.  */
 
   int use_keyboxd;       /* Use the external keyboxd as storage backend.  */
+
+  /* Compatibility flags (COMPAT_FLAG_xxxx).  */
+  unsigned int compat_flags;
 } opt;
 
 /* CTRL is used to keep some global variables we currently can't
@@ -363,8 +366,11 @@ struct {
 EXTERN_UNLESS_MAIN_MODULE int memory_debug_mode;
 EXTERN_UNLESS_MAIN_MODULE int memory_stat_debug_mode;
 
+/* Compatibility flags */
+/* #define COMPAT_FOO   1 */
 
-/* Compatibility flags.  */
+
+/* Compliance test macors.  */
 #define GNUPG   (opt.compliance==CO_GNUPG || opt.compliance==CO_DE_VS)
 #define RFC2440 (opt.compliance==CO_RFC2440)
 #define RFC4880 (opt.compliance==CO_RFC4880)