discover/pxe-parser: Parse only the first config

[petitboot] / discover / pxe-parser.c

diff --git a/discover/pxe-parser.c b/discover/pxe-parser.c
index 4481e5da9f7c9709d31cea7e00e29709cf203d38..43520364982e865b302dc32a5920d394f88ccb76 100644 (file)
--- a/discover/pxe-parser.c
+++ b/discover/pxe-parser.c
@@ -22,9 +22,14 @@
 
 static const char *pxelinux_prefix = "pxelinux.cfg/";
 
+static void pxe_conf_parse_cb(struct load_url_result *result, void *data);
+
 struct pxe_parser_info {
-       struct discover_boot_option *opt;
-       const char *default_name;
+       struct discover_boot_option     *opt;
+       const char                      *default_name;
+       char                            **pxe_conf_files;
+       struct pb_url                   *pxe_base_url;
+       int                             current;
 };
 
 static void pxe_finish(struct conf_context *conf)
@@ -166,6 +171,13 @@ static void pxe_process_pair(struct conf_context *ctx,
                url = pxe_url_join(ctx->dc, ctx->dc->conf_url, value);
                opt->boot_image = create_url_resource(opt, url);
 
+               char* args_sigfile_default = talloc_asprintf(opt,
+                       "%s.cmdline.sig", value);
+               url = pxe_url_join(ctx->dc, ctx->dc->conf_url,
+                       args_sigfile_default);
+               opt->args_sig_file = create_url_resource(opt, url);
+               talloc_free(args_sigfile_default);
+
        } else if (streq(name, "INITRD")) {
                url = pxe_url_join(ctx->dc, ctx->dc->conf_url, value);
                opt->initrd = create_url_resource(opt, url);
@@ -199,6 +211,27 @@ static void pxe_process_pair(struct conf_context *ctx,
 
 }
 
+static void pxe_load_next_filename(struct conf_context *conf)
+{
+       struct pxe_parser_info *info = conf->parser_info;
+       struct pb_url *url;
+
+       if (!info->pxe_conf_files)
+               return;
+
+       for (; info->pxe_conf_files[info->current]; info->current++) {
+               url = pb_url_join(conf->dc, info->pxe_base_url,
+                                 info->pxe_conf_files[info->current]);
+               if (!url)
+                       continue;
+
+               if (load_url_async(conf, url, pxe_conf_parse_cb, conf))
+                       break;
+       }
+
+       return;
+}
+
 /*
  * Callback for asynchronous loads from pxe_parse()
  * @param result Result of load_url_async()
@@ -209,22 +242,35 @@ static void pxe_conf_parse_cb(struct load_url_result *result, void *data)
        struct conf_context *conf = data;
        struct device_handler *handler;
        struct boot_status status = {0};
+       struct pxe_parser_info *info;
        char *buf = NULL;
-       int len, rc;
+       int len, rc = 0;
 
        if (!data)
                return;
 
-       if (!result || result->status != LOAD_OK) {
-               talloc_free(conf);
+       if (result && result->status == LOAD_OK)
+               rc = read_file(conf, result->local, &buf, &len);
+       if (!result || result->status != LOAD_OK || rc) {
+               /* This load failed so try the next available filename */
+               info = conf->parser_info;
+               if (!info->pxe_conf_files)
+                       return;
+
+               info->current++;
+               pxe_load_next_filename(conf);
+               if (info->pxe_conf_files[info->current] == NULL) {
+                       /* Nothing left to try */
+                       goto out_clean;
+               }
                return;
        }
 
-       rc = read_file(conf, result->local, &buf, &len);
-       if (rc) {
-               pb_log("Read failed during pxe callback for %s\n", result->local);
-               goto out_clean;
-       }
+       /*
+        * 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
+        */
 
        conf_parse_buf(conf, buf, len);
 
@@ -288,11 +334,12 @@ static struct conf_context *copy_context(void *ctx, struct discover_context *dc)
 
 static int pxe_parse(struct discover_context *dc)
 {
-       struct pb_url *pxe_base_url, *url;
-       char **pxe_conf_files, **filename;
+       struct pb_url *pxe_base_url;
        struct conf_context *conf = NULL;
        struct load_url_result *result;
        void *ctx = talloc_parent(dc);
+       struct pxe_parser_info *info;
+       char **pxe_conf_files;
        bool complete_url;
 
        /* Expects dhcp event parameters to support network boot */
@@ -307,9 +354,9 @@ static int pxe_parse(struct discover_context *dc)
         * Retrieving PXE configs over the network can take some time depending
         * on factors such as slow network, malformed paths, bad DNS, and
         * overzealous firewalls. Instead of blocking the discover server while
-        * we wait for these, spawn an asynchronous job for each URL we can
-        * parse and process the resulting files in a callback. A separate
-        * conf_context is created for each job.
+        * we wait for these, spawn an asynchronous job that will attempt to
+        * retrieve each possible URL until it successfully finds one, and
+        * parse and process the resulting file in a callback.
         */
        conf = copy_context(ctx, dc);
        if (!conf)
@@ -333,26 +380,11 @@ static int pxe_parse(struct discover_context *dc)
                if (!pxe_base_url)
                        goto out_pxe_conf;
 
-               for (filename = pxe_conf_files; *filename; filename++) {
-                       if (!conf) {
-                               conf = copy_context(ctx, dc);
-                       }
-                       url = pb_url_join(conf->dc, pxe_base_url, *filename);
-                       if (!url)
-                               continue;
-                       result = load_url_async(conf, url, pxe_conf_parse_cb,
-                                               conf);
-                       if (!result) {
-                               pb_log("load_url_async fails for %s\n",
-                                      conf->dc->conf_url->path);
-                               talloc_free(conf);
-                       }
-                       /* conf now needed by callback, don't reuse */
-                       conf = NULL;
-               }
+               info = conf->parser_info;
+               info->pxe_conf_files = pxe_conf_files;
+               info->pxe_base_url = pxe_base_url;
 
-               talloc_free(pxe_base_url);
-               talloc_free(pxe_conf_files);
+               pxe_load_next_filename(conf);
        }
 
        return 0;