discover: Allow an in-progress boot to be cancelled
[petitboot] / discover / boot.c
index ec6f6e579eb6cb31f8929c1ab140accc9be99b35..0237b0c962209fe65aa8b2f394946adbc24d656f 100644 (file)
@@ -9,6 +9,7 @@
 #include <fcntl.h>
 #include <sys/types.h>
 
+#include <array-size/array-size.h>
 #include <log/log.h>
 #include <pb-protocol/pb-protocol.h>
 #include <process/process.h>
@@ -35,6 +36,7 @@ struct boot_task {
        boot_status_fn status_fn;
        void *status_arg;
        bool dry_run;
+       bool cancelled;
 };
 
 /**
@@ -308,12 +310,50 @@ static void cleanup_load(struct load_url_result *result)
        unlink(result->local);
 }
 
-static void boot_process(struct load_url_result *result __attribute__((unused)),
-               void *data)
+static void cleanup_cancellations(struct boot_task *task,
+               struct load_url_result *cur_result)
+{
+       struct load_url_result *result, **results[] = {
+               &task->image, &task->initrd, &task->dtb,
+       };
+       bool pending = false;
+       unsigned int i;
+
+       for (i = 0; i < ARRAY_SIZE(results); i++) {
+               result = *results[i];
+
+               if (!result)
+                       continue;
+
+               /* We need to cleanup and free any completed loads */
+               if (result == cur_result || result->status == LOAD_OK
+                               || result->status == LOAD_ERROR) {
+                       cleanup_load(result);
+                       talloc_free(result);
+                       *results[i] = NULL;
+
+               /* ... and cancel any pending loads, which we'll free in
+                * the completion callback */
+               } else if (result->status == LOAD_ASYNC) {
+                       load_url_async_cancel(result);
+                       pending = true;
+               }
+       }
+
+       if (!pending)
+               talloc_free(task);
+}
+
+static void boot_process(struct load_url_result *result, void *data)
 {
        struct boot_task *task = data;
        int rc = -1;
 
+       if (task->cancelled) {
+               cleanup_cancellations(task, result);
+               return;
+       }
+
        if (load_pending(task->image) ||
                        load_pending(task->initrd) ||
                        load_pending(task->dtb))
@@ -352,8 +392,6 @@ no_load:
                                        "kexec reboot failed");
                }
        }
-
-       talloc_free(task);
 }
 
 static int start_url_load(struct boot_task *task, const char *name,
@@ -372,8 +410,9 @@ static int start_url_load(struct boot_task *task, const char *name,
        return 0;
 }
 
-int boot(void *ctx, struct discover_boot_option *opt, struct boot_command *cmd,
-               int dry_run, boot_status_fn status_fn, void *status_arg)
+struct boot_task *boot(void *ctx, struct discover_boot_option *opt,
+               struct boot_command *cmd, int dry_run,
+               boot_status_fn status_fn, void *status_arg)
 {
        struct pb_url *image = NULL, *initrd = NULL, *dtb = NULL;
        struct boot_task *boot_task;
@@ -398,7 +437,7 @@ int boot(void *ctx, struct discover_boot_option *opt, struct boot_command *cmd,
                pb_log("%s: no image specified\n", __func__);
                update_status(status_fn, status_arg, BOOT_STATUS_INFO,
                                "Boot failed: no image specified");
-               return -1;
+               return NULL;
        }
 
        if (cmd && cmd->initrd_file) {
@@ -433,8 +472,22 @@ int boot(void *ctx, struct discover_boot_option *opt, struct boot_command *cmd,
          || start_url_load(boot_task, "dtb", dtb, &boot_task->dtb);
 
        /* If all URLs are local, we may be done. */
-       if (!rc)
-               boot_process(NULL, boot_task);
+       if (rc) {
+               talloc_free(boot_task);
+               return NULL;
+       }
+
+       boot_process(NULL, boot_task);
+
+       return boot_task;
+}
+
+void boot_cancel(struct boot_task *task)
+{
+       task->cancelled = true;
+
+       update_status(task->status_fn, task->status_arg, BOOT_STATUS_INFO,
+                       "Boot cancelled");
 
-       return rc;
+       cleanup_cancellations(task, NULL);
 }