gpg: Add ostree_gpg_verify_result_describe()

Internalizes the signature output of "ostree show" so it can be reused
elsewhere.

doc/ostree-sections.txt

@@ -174,6 +174,8 @@ ostree_gpg_verify_result_count_valid
 ostree_gpg_verify_result_lookup
 ostree_gpg_verify_result_get
 ostree_gpg_verify_result_get_all
+OstreeGpgSignatureFormatFlags
+ostree_gpg_verify_result_describe
 <SUBSECTION Standard>
 OSTREE_GPG_VERIFY_RESULT
 OSTREE_IS_GPG_VERIFY_RESULT

src/libostree/ostree-gpg-verify-result.c

@@ -20,6 +20,9 @@
 
 #include "config.h"
 
+#include <string.h>
+
+#include "libglnx.h"
 #include "libgsystem.h"
 
 #include "ostree-gpg-verify-result-private.h"
@@ -451,6 +454,147 @@ ostree_gpg_verify_result_get_all (OstreeGpgVerifyResult *result,
                                        G_N_ELEMENTS (all_signature_attrs));
 }
 
+/**
+ * ostree_gpg_verify_result_describe:
+ * @result: an #OstreeGpgVerifyResult
+ * @signature_index: which signature to describe
+ * @output_buffer: a #GString to hold the description
+ * @line_prefix: (allow-none): optional line prefix string
+ * @flags: flags to adjust the description format
+ *
+ * Appends a brief, human-readable description of the GPG signature at
+ * @signature_index in @result to the @output_buffer.  The description
+ * spans multiple lines.  A @line_prefix string, if given, will precede
+ * each line of the description.
+ *
+ * The @flags argument is reserved for future variations to the description
+ * format.  Currently must be 0.
+ *
+ * It is a programmer error to request an invalid @signature_index.  Use
+ * ostree_gpg_verify_result_count_all() to find the number of signatures in
+ * @result.
+ */
+void
+ostree_gpg_verify_result_describe (OstreeGpgVerifyResult *result,
+                                   guint signature_index,
+                                   GString *output_buffer,
+                                   const gchar *line_prefix,
+                                   OstreeGpgSignatureFormatFlags flags)
+{
+  g_autoptr(GVariant) variant = NULL;
+  g_autoptr(GDateTime) date_time_utc = NULL;
+  g_autoptr(GDateTime) date_time_local = NULL;
+  g_autofree char *formatted_date_time = NULL;
+  gint64 timestamp;
+  gint64 exp_timestamp;
+  const char *fingerprint;
+  const char *pubkey_algo;
+  const char *user_name;
+  const char *user_email;
+  const char *key_id;
+  gboolean valid;
+  gboolean sig_expired;
+  gboolean key_missing;
+  gsize len;
+
+  g_return_if_fail (OSTREE_IS_GPG_VERIFY_RESULT (result));
+  g_return_if_fail (output_buffer != NULL);
+
+  /* The default format roughly mimics the verify output generated by
+   * check_sig_and_print() in gnupg/g10/mainproc.c, though obviously
+   * greatly simplified. */
+
+  variant = ostree_gpg_verify_result_get_all (result, signature_index);
+  g_return_if_fail (variant != NULL);
+
+  g_variant_get_child (variant, OSTREE_GPG_SIGNATURE_ATTR_VALID,
+                       "b", &valid);
+  g_variant_get_child (variant, OSTREE_GPG_SIGNATURE_ATTR_SIG_EXPIRED,
+                       "b", &sig_expired);
+  g_variant_get_child (variant, OSTREE_GPG_SIGNATURE_ATTR_KEY_MISSING,
+                       "b", &key_missing);
+  g_variant_get_child (variant, OSTREE_GPG_SIGNATURE_ATTR_FINGERPRINT,
+                       "&s", &fingerprint);
+  g_variant_get_child (variant, OSTREE_GPG_SIGNATURE_ATTR_TIMESTAMP,
+                       "x", &timestamp);
+  g_variant_get_child (variant, OSTREE_GPG_SIGNATURE_ATTR_EXP_TIMESTAMP,
+                       "x", &exp_timestamp);
+  g_variant_get_child (variant, OSTREE_GPG_SIGNATURE_ATTR_PUBKEY_ALGO_NAME,
+                       "&s", &pubkey_algo);
+  g_variant_get_child (variant, OSTREE_GPG_SIGNATURE_ATTR_USER_NAME,
+                       "&s", &user_name);
+  g_variant_get_child (variant, OSTREE_GPG_SIGNATURE_ATTR_USER_EMAIL,
+                       "&s", &user_email);
+
+  len = strlen (fingerprint);
+  key_id = (len > 16) ? fingerprint + len - 16 : fingerprint;
+
+  date_time_utc = g_date_time_new_from_unix_utc (timestamp);
+  date_time_local = g_date_time_to_local (date_time_utc);
+  formatted_date_time = g_date_time_format (date_time_local, "%c");
+
+  if (line_prefix != NULL)
+    g_string_append (output_buffer, line_prefix);
+
+  g_string_append_printf (output_buffer,
+                          "Signature made %s using %s key ID %s\n",
+                          formatted_date_time, pubkey_algo, key_id);
+
+  g_clear_pointer (&date_time_utc, g_date_time_unref);
+  g_clear_pointer (&date_time_local, g_date_time_unref);
+  g_clear_pointer (&formatted_date_time, g_free);
+
+  if (line_prefix != NULL)
+    g_string_append (output_buffer, line_prefix);
+
+  if (key_missing)
+    {
+      g_string_append (output_buffer,
+                       "Can't check signature: public key not found\n");
+    }
+  else if (valid)
+    {
+      g_string_append_printf (output_buffer,
+                              "Good signature from \"%s <%s>\"\n",
+                              user_name, user_email);
+    }
+  else if (sig_expired)
+    {
+      g_string_append_printf (output_buffer,
+                              "Expired signature from \"%s <%s>\"\n",
+                              user_name, user_email);
+    }
+  else
+    {
+      g_string_append_printf (output_buffer,
+                              "BAD signature from \"%s <%s>\"\n",
+                              user_name, user_email);
+    }
+
+  if (exp_timestamp > 0)
+    {
+      date_time_utc = g_date_time_new_from_unix_utc (exp_timestamp);
+      date_time_local = g_date_time_to_local (date_time_utc);
+      formatted_date_time = g_date_time_format (date_time_local, "%c");
+
+      if (line_prefix != NULL)
+        g_string_append (output_buffer, line_prefix);
+
+      if (sig_expired)
+        {
+          g_string_append_printf (output_buffer,
+                                  "Signature expired %s\n",
+                                  formatted_date_time);
+        }
+      else
+        {
+          g_string_append_printf (output_buffer,
+                                  "Signature expires %s\n",
+                                  formatted_date_time);
+        }
+    }
+}
+
 void
 _ostree_gpg_error_to_gio_error (gpgme_error_t   gpg_error,
                                 GError        **error)

src/libostree/ostree-gpg-verify-result.h

@@ -100,4 +100,23 @@ GVariant * ostree_gpg_verify_result_get (OstreeGpgVerifyResult *result,
 GVariant * ostree_gpg_verify_result_get_all (OstreeGpgVerifyResult *result,
                                              guint signature_index);
 
+/**
+ * OstreeGpgSignatureFormatFlags:
+ * @OSTREE_GPG_SIGNATURE_FORMAT_DEFAULT:
+ *   Use the default output format
+ *
+ * Formatting flags for ostree_gpg_verify_result_describe().  Currently
+ * there's only one possible output format, but this enumeration allows
+ * for future variations.
+ **/
+typedef enum {
+  OSTREE_GPG_SIGNATURE_FORMAT_DEFAULT = 0
+} OstreeGpgSignatureFormatFlags;
+
+void ostree_gpg_verify_result_describe (OstreeGpgVerifyResult *result,
+                                        guint signature_index,
+                                        GString *output_buffer,
+                                        const gchar *line_prefix,
+                                        OstreeGpgSignatureFormatFlags flags);
+
 G_END_DECLS

src/ostree/ot-builtin-show.c

@@ -148,87 +148,6 @@ do_print_metadata_key (OstreeRepo     *repo,
   return ret;
 }
 
-static void
-print_signature (OstreeGpgVerifyResult *result,
-                 guint signature_index)
-{
-  g_autoptr(GVariant) variant = NULL;
-  g_autoptr(GDateTime) date_time_utc = NULL;
-  g_autoptr(GDateTime) date_time_local = NULL;
-  g_autofree char *formatted_date_time = NULL;
-  gint64 timestamp;
-  gint64 exp_timestamp;
-  const char *fingerprint;
-  const char *pubkey_algo;
-  const char *user_name;
-  const char *user_email;
-  const char *key_id;
-  gboolean valid;
-  gboolean sig_expired;
-  gboolean key_missing;
-  gsize len;
-
-  /* This function roughly mimics the verify output generated by
-   * check_sig_and_print() in gnupg/g10/mainproc.c, though obviously
-   * greatly simplified. */
-
-  variant = ostree_gpg_verify_result_get_all (result, signature_index);
-
-  g_variant_get_child (variant, OSTREE_GPG_SIGNATURE_ATTR_VALID,
-                       "b", &valid);
-  g_variant_get_child (variant, OSTREE_GPG_SIGNATURE_ATTR_SIG_EXPIRED,
-                       "b", &sig_expired);
-  g_variant_get_child (variant, OSTREE_GPG_SIGNATURE_ATTR_KEY_MISSING,
-                       "b", &key_missing);
-  g_variant_get_child (variant, OSTREE_GPG_SIGNATURE_ATTR_FINGERPRINT,
-                       "&s", &fingerprint);
-  g_variant_get_child (variant, OSTREE_GPG_SIGNATURE_ATTR_TIMESTAMP,
-                       "x", &timestamp);
-  g_variant_get_child (variant, OSTREE_GPG_SIGNATURE_ATTR_EXP_TIMESTAMP,
-                       "x", &exp_timestamp);
-  g_variant_get_child (variant, OSTREE_GPG_SIGNATURE_ATTR_PUBKEY_ALGO_NAME,
-                       "&s", &pubkey_algo);
-  g_variant_get_child (variant, OSTREE_GPG_SIGNATURE_ATTR_USER_NAME,
-                       "&s", &user_name);
-  g_variant_get_child (variant, OSTREE_GPG_SIGNATURE_ATTR_USER_EMAIL,
-                       "&s", &user_email);
-
-  len = strlen (fingerprint);
-  key_id = (len > 16) ? fingerprint + len - 16 : fingerprint;
-
-  date_time_utc = g_date_time_new_from_unix_utc (timestamp);
-  date_time_local = g_date_time_to_local (date_time_utc);
-  formatted_date_time = g_date_time_format (date_time_local, "%c");
-
-  g_print ("  Signature made %s using %s key ID %s\n",
-           formatted_date_time, pubkey_algo, key_id);
-
-  g_clear_pointer (&date_time_utc, g_date_time_unref);
-  g_clear_pointer (&date_time_local, g_date_time_unref);
-  g_clear_pointer (&formatted_date_time, g_free);
-
-  if (key_missing)
-    g_print ("  Can't check signature: public key not found\n");
-  else if (valid)
-    g_print ("  Good signature from \"%s <%s>\"\n", user_name, user_email);
-  else if (sig_expired)
-    g_print ("  Expired signature from \"%s <%s>\"\n", user_name, user_email);
-  else
-    g_print ("  BAD signature from \"%s <%s>\"\n", user_name, user_email);
-
-  if (exp_timestamp > 0)
-    {
-      date_time_utc = g_date_time_new_from_unix_utc (exp_timestamp);
-      date_time_local = g_date_time_to_local (date_time_utc);
-      formatted_date_time = g_date_time_format (date_time_local, "%c");
-
-      if (sig_expired)
-        g_print ("  Signature expired %s\n", formatted_date_time);
-      else
-        g_print ("  Signature expires %s\n", formatted_date_time);
-    }
-}
-
 static gboolean
 print_object (OstreeRepo          *repo,
               OstreeObjectType     objtype,
@@ -266,16 +185,23 @@ print_object (OstreeRepo          *repo,
         }
       else
         {
+          GString *buffer;
           guint n_sigs, ii;
 
           n_sigs = ostree_gpg_verify_result_count_all (result);
           g_print ("Found %u signature%s:\n", n_sigs, n_sigs == 1 ? "" : "s");
 
+          buffer = g_string_sized_new (256);
+
           for (ii = 0; ii < n_sigs; ii++)
             {
-              g_print ("\n");
+              g_string_append_c (buffer, '\n');
-              print_signature (result, ii);
+              ostree_gpg_verify_result_describe (result, ii, buffer, "  ",
+                                                 OSTREE_GPG_SIGNATURE_FORMAT_DEFAULT);
             }
+
+          g_print ("%s", buffer->str);
+          g_string_free (buffer, TRUE);
         }
     }