- Added a configuration function, 'gethostname()', which calls the system

[thirdparty/dhcp.git] / common / tree.c

diff --git a/common/tree.c b/common/tree.c
index 5244a1965c31b18dfdd98eee2624f094584e0e7a..2e4616f3cb32a8b0f98f7b9ca0a7958f1e2accb3 100644 (file)
--- a/common/tree.c
+++ b/common/tree.c
@@ -951,6 +951,7 @@ int evaluate_dns_expression (result, packet, lease, client_state, in_options,
              case expr_config_option:
              case expr_leased_address:
              case expr_null:
+             case expr_gethostname:
                log_error ("Data opcode in evaluate_dns_expression: %d",
                      expr -> op);
                return 0;
@@ -1376,6 +1377,7 @@ int evaluate_boolean_expression (result, packet, lease, client_state,
              case expr_null:
              case expr_filename:
              case expr_sname:
+             case expr_gethostname:
                log_error ("Data opcode in evaluate_boolean_expression: %d",
                      expr -> op);
                return 0;
@@ -2299,6 +2301,39 @@ int evaluate_data_expression (result, packet, lease, client_state,
 #endif
                return s0;
 
+               /* Provide the system's local hostname as a return value. */
+             case expr_gethostname:
+               /*
+                * Allocate a buffer to return.
+                *
+                * The largest valid hostname is maybe 64 octets at a single
+                * label, or 255 octets if you think a hostname is allowed
+                * to contain labels (plus termination).
+                */
+               memset(result, 0, sizeof(*result));
+               if (!buffer_allocate(&result->buffer, 255, file, line)) {
+                       log_error("data: gethostname(): no memory for buffer");
+                       return 0;
+               }
+               result->data = result->buffer->data;
+
+               /*
+                * On successful completion, gethostname() resturns 0.  It may
+                * not null-terminate the string if there was insufficient
+                * space.
+                */
+               if (!gethostname((char *)result->buffer->data, 255)) {
+                       if (result->buffer->data[255] == '\0')
+                               result->len =
+                                       strlen((char *)result->buffer->data);
+                       else
+                               result->len = 255;
+                       return 1;
+               }
+
+               data_string_forget(result, MDL);
+               return 0;
+
              case expr_check:
              case expr_equal:
              case expr_not_equal:
@@ -2420,6 +2455,7 @@ int evaluate_numeric_expression (result, packet, lease, client_state,
              case expr_config_option:
              case expr_leased_address:
              case expr_null:
+             case expr_gethostname:
                log_error ("Data opcode in evaluate_numeric_expression: %d",
                      expr -> op);
                return 0;
@@ -3202,6 +3238,7 @@ void expression_dereference (eptr, file, line)
              case expr_exists:
              case expr_known:
              case expr_null:
+             case expr_gethostname:
                break;
 
              default:
@@ -3261,7 +3298,8 @@ int is_data_expression (expr)
                expr->op == expr_host_decl_name ||
                expr->op == expr_leased_address ||
                expr->op == expr_config_option ||
-               expr->op == expr_null);
+               expr->op == expr_null ||
+               expr->op == expr_gethostname);
 }
 
 int is_numeric_expression (expr)
@@ -3364,6 +3402,7 @@ static int op_val (op)
              case expr_binary_or:
              case expr_binary_xor:
              case expr_client_state:
+             case expr_gethostname:
                return 100;
 
              case expr_equal:
@@ -3457,6 +3496,7 @@ enum expression_context op_context (op)
              case expr_arg:
              case expr_funcall:
              case expr_function:
+             case expr_gethostname:
                return context_any;
 
              case expr_equal:
@@ -3988,6 +4028,11 @@ int write_expression (file, expr, col, indent, firstp)
                col = token_print_indent (file, col, indent, "", "", ")");
                break;
 
+             case expr_gethostname:
+               col = token_print_indent(file, col, indent, "", "",
+                                        "gethostname()");
+               break;
+
              default:
                log_fatal ("invalid expression type in print_expression: %d",
                           expr -> op);
@@ -4241,6 +4286,7 @@ int data_subexpression_length (int *rv,
              case expr_binary_or:
              case expr_binary_xor:
              case expr_client_state:
+             case expr_gethostname:
                return 0;
        }
        return 0;