discover/pxe-parser: Parse simple iPXE scripts

[petitboot] / discover / pxe-parser.c

diff --git a/discover/pxe-parser.c b/discover/pxe-parser.c
index 470dd83f08ad71590339156ac1bc10c853152532..9221f95ae07744cb5cd136ed0187c429cc413f8a 100644 (file)
--- a/discover/pxe-parser.c
+++ b/discover/pxe-parser.c
@@ -259,6 +259,97 @@ static void pxe_load_next_filename(struct conf_context *conf)
        return;
 }
 
+/*
+ * Parse a limited set of iPXE commands. This is handled separately from
+ * conf_parse_buf() since not all commands will have a value.
+ */
+static bool ipxe_simple_parser(struct conf_context *ctx, char *buf, int len)
+{
+       struct discover_boot_option *opt;
+       char *p, *name, *value;
+       struct pb_url *url;
+
+       p = strstr(buf, "#!ipxe");
+
+       /* Only try to parse this if the ipxe header is right at the start */
+       if (!p || p != buf)
+               return false;
+       p = strchr(buf, '\n') + 1;
+
+       opt = discover_boot_option_create(ctx->dc, ctx->dc->device);
+
+       opt->option->id = talloc_asprintf(opt, "%s@%p",
+                       ctx->dc->device->device->id, opt);
+       opt->option->type = DISCOVER_BOOT_OPTION;
+
+       while (p && p <= buf + len) {
+
+               p = conf_get_pair(ctx, p, &name, &value, ' ', '\n');
+
+               /* The 'boot' command appears by itself without options */
+               if (!name && value && streq(value, "boot")) {
+                       opt->option->is_default = true;
+                       continue;
+               }
+
+               /* All other parameters require a value */
+               if (!value) {
+                       pb_debug("%s: '%s' missing value\n", __func__, name);
+                       continue;
+               }
+
+               if (streq(name, "kernel")) {
+                       char *args, *name = NULL, *saveptr = NULL, *tmp;
+
+                       /*
+                        * value is of the form:
+                        * boot_image [--name option_name ] [option args ...]
+                        */
+                       tmp = strtok_r(value, " ", &saveptr);
+                       if (!tmp) {
+                               pb_log("%s: malformed kernel statement\n", __func__);
+                               break;
+                       }
+
+                       url = pxe_url_join(ctx->dc, ctx->dc->conf_url, tmp);
+                       opt->boot_image = create_url_resource(opt, url);
+
+                       tmp = strtok_r(NULL, " ", &saveptr);
+                       if (!tmp)
+                               continue;
+                       if (streq(tmp, "--name")) {
+                               tmp = strtok_r(NULL, " ", &saveptr);
+                               name = talloc_asprintf(opt, "%s",
+                                               tmp ?: "malformed ipxe option");
+                               args = strtok_r(NULL, " ", &saveptr);
+                       } else
+                               args = tmp;
+
+                       while (args) {
+                               pxe_append_string(opt, args);
+                               args = strtok_r(NULL, " ", &saveptr);
+                       }
+
+                       opt->option->name = name ?: talloc_asprintf(opt,
+                                       "ipxe option (%s)", url->full);
+                       continue;
+               }
+
+               if (streq(name, "initrd")) {
+                       url = pxe_url_join(ctx->dc, ctx->dc->conf_url, value);
+                       opt->initrd = create_url_resource(opt, url);
+                       continue;
+               }
+       }
+
+       if (opt->boot_image)
+               discover_context_add_boot_option(ctx->dc, opt);
+       else
+               pb_debug("ipxe file did not contain a valid option\n");
+
+       return true;
+}
+
 /*
  * Callback for asynchronous loads from pxe_parse()
  * @param result Result of load_url_async()
@@ -309,9 +400,10 @@ static void pxe_conf_parse_cb(struct load_url_result *result, void *data)
         * Parse the first successfully downloaded file. We only want to parse
         * the first because otherwise we could parse options from both a
         * machine-specific config and a 'fallback' default config
+        * We also check if the file is in the limited ipxe format.
         */
-
-       conf_parse_buf(conf, buf, len);
+       if (!ipxe_simple_parser(conf, buf, len))
+               conf_parse_buf(conf, buf, len);
 
        /* We may be called well after the original caller of iterate_parsers(),
         * commit any new boot options ourselves */