Support multiple tasks in --task

Based on the discussion in fwup-home#185

The idea is that you can specify a list of tasks with `-t` and fwup
will try each one until the first success supporting a "fallback"
behavior

src/functions.h

@@ -49,6 +49,9 @@ struct fun_context {
     // Task configuration
     cfg_t *task;
 
+    // Lists of task configurations
+    cfg_t *tasks[16];
+
     // When processing events (on-init, on-resource, on-finish, etc.) this is that configuration
     cfg_t *on_event;
 

src/fwup_apply.c

@@ -99,6 +99,22 @@ static cfg_t *find_task(struct fun_context *fctx, const char *task_prefix)
     return 0;
 }
 
+static int find_tasks(struct fun_context *fctx, const char *tasks_prefix)
+{
+    int rc = -1;
+    int i = 0;
+    char *tasks_copy = strdup(tasks_prefix);
+    for (char *task_prefix = strtok(tasks_copy, ":"); task_prefix != NULL; task_prefix = strtok(NULL, ";")) {
+        fctx->tasks[i] = find_task(fctx, task_prefix);
+        // First task found sets return code as successful
+        if (rc < 0 && fctx->tasks[i] != 0)
+            rc = 0;
+        i++;
+    }
+    free(tasks_copy);
+    return rc;
+}
+
 static int apply_event(struct fun_context *fctx, cfg_t *task, const char *event_type, const char *event_parameter, int (*fun)(struct fun_context *fctx))
 {
     if (event_parameter)
@@ -452,6 +468,20 @@ static int run_task(struct fun_context *fctx, struct fwup_apply_data *pd)
     return rc;
 }
 
+static int run_tasks(struct fun_context *fctx, struct fwup_apply_data *pd)
+{
+    int rc = 0;
+    for (int i = 0; fctx->tasks[i] != 0; i++) {
+        fctx->task = fctx->tasks[i];
+        rc = run_task(fctx, pd);
+        if (rc == 0)
+            return 0;
+        // Maybe we should report this task failed and moving on to the next one?
+    }
+    // No task was successful
+    return -1;
+}
+
 int fwup_apply(const char *fw_filename,
                const char *task_prefix,
                int output_fd,
@@ -511,15 +541,17 @@ int fwup_apply(const char *fw_filename,
     OK_OR_CLEANUP(block_cache_init(fctx.output, output_fd, end_offset, enable_trim, verify_writes));
 
     // Go through all of the tasks and find a matcher
-    fctx.task = find_task(&fctx, task_prefix);
-    if (fctx.task == 0)
+    // fctx.task = find_task(&fctx, task_prefix);
+    int task_rc = find_tasks(&fctx, task_prefix);
+    if (task_rc < 0)
         ERR_CLEANUP_MSG("Couldn't find applicable task '%s'. If task is available, the task's requirements may not be met.", task_prefix);
 
     // Compute the total progress units
     OK_OR_CLEANUP(compute_progress(&fctx));
 
     // Run
-    OK_OR_CLEANUP(run_task(&fctx, &pd));
+    // OK_OR_CLEANUP(run_task(&fctx, &pd));
+    OK_OR_CLEANUP(run_tasks(&fctx, &pd));
 
     // Flush everything
     fatfs_closefs();

tests/192_multiple_tasks.test

@@ -0,0 +1,42 @@
+#/bin/sh
+
+#
+# Test that multiple tasks are attempted until success with a task list
+#
+
+. "$(cd "$(dirname "$0")" && pwd)/common.sh"
+
+cat >$CONFIG <<EOF
+file-resource TEST {
+        host-path = "${TESTFILE_1K}"
+}
+
+task complete {
+on-resource TEST { raw_write(0) }
+}
+EOF
+
+cat >$EXPECTED_META_CONF <<EOF
+file-resource "TEST" {
+length=1024
+blake2b-256="b25c2dfe31707f5572d9a3670d0dcfe5d59ccb010e6aba3b81aad133eb5e378b"
+}
+task "complete" {
+on-resource "TEST" {
+funlist = {"2", "raw_write", "0"}
+}
+}
+EOF
+
+$FWUP_CREATE -c -f $CONFIG -o $FWFILE
+
+# Check that the zip file was created as expected
+check_meta_conf
+cmp $TESTFILE_1K $UNZIPDIR/data/TEST
+
+# The upgrade task does not exist, so it should fallback to the complete task
+$FWUP_APPLY -a -d $IMGFILE -i $FWFILE -t upgrade:complete
+cmp_bytes 1024 $IMGFILE $TESTFILE_1K
+
+# Check that the verify logic works on this file
+$FWUP_VERIFY -V -i $FWFILE

tests/Makefile.am

@@ -191,6 +191,7 @@ TESTS = 001_simple_fw.test \
 	188_uboot_redundant_bad_param.test \
 	189_uboot_redundant_recover.test \
 	190_one_metadata_cmdline.test \
-	191_disk_crypto_via_env.test
+	191_disk_crypto_via_env.test \
+	192_multiple_tasks.test
 
 EXTRA_DIST = $(TESTS) common.sh 1K.bin 1K-corrupt.bin 150K.bin