Allow top-down evaluation of promises

Ticket: ENT-10184
Signed-off-by: Victor Moene <victor.moene@northern.tech>

Author: victormlg

cf-agent/cf-agent.c

@@ -1559,6 +1559,15 @@ static void AllClassesReport(const EvalContext *ctx)
 
 PromiseResult ScheduleAgentOperations(EvalContext *ctx, const Bundle *bp)
 // NB - this function can be called recursively through "methods"
+{
+    if (EvalContextGetEvalOption(ctx, EVAL_OPTION_NORMAL_EVALUATION))
+    {
+        return ScheduleAgentOperationsNormalOrder(ctx, bp);
+    }
+    return ScheduleAgentOperationsTopDownOrder(ctx, bp);
+}
+
+PromiseResult ScheduleAgentOperationsNormalOrder(EvalContext *ctx, const Bundle *bp)
 {
     assert(bp != NULL);
 
@@ -1652,6 +1661,78 @@ PromiseResult ScheduleAgentOperations(EvalContext *ctx, const Bundle *bp)
     return result;
 }
 
+int PromiseCmpWrapper(const Promise *p1, const Promise *p2, void *user_data)
+{
+    UNUSED(user_data);
+    if (p1->offset.start < p2->offset.start)
+    {
+        return -1;
+    }
+    else if (p1->offset.start > p2->offset.start)
+    {
+        return 1;
+    }
+    return 0;
+}
+
+PromiseResult ScheduleAgentOperationsTopDownOrder(EvalContext *ctx, const Bundle *bp)
+{
+    assert(bp != NULL);
+
+    int save_pr_kept = PR_KEPT;
+    int save_pr_repaired = PR_REPAIRED;
+    int save_pr_notkept = PR_NOTKEPT;
+    struct timespec start = BeginMeasure();
+
+    if (PROCESSREFRESH == NULL || (PROCESSREFRESH && IsRegexItemIn(ctx, PROCESSREFRESH, bp->name)))
+    {
+        ClearProcessTable();
+    }
+
+    Seq *promise_sequence = SeqNew(10, NULL);
+
+    const size_t sections = SeqLength(bp->sections);
+    for (size_t i = 0; i < sections; i++)
+    {
+        BundleSection *section = SeqAt(bp->sections, i);
+        const size_t promises = SeqLength(section->promises);
+
+        for (size_t j = 0; j < promises; j++)
+        {
+            SeqAppend(promise_sequence, SeqAt(section->promises, j));
+        }
+    }
+
+    SeqSort(promise_sequence, PromiseCmpWrapper, NULL);
+
+    PromiseResult result = PROMISE_RESULT_SKIPPED;
+    for (int pass = 1; pass < CF_DONEPASSES; pass++)
+    {
+        for (size_t ppi = 0; ppi < SeqLength(promise_sequence); ppi++)
+        {
+            Promise *pp = SeqAt(promise_sequence, ppi);
+            BundleSection *parent_section = pp->parent_section;
+
+            EvalContextStackPushBundleSectionFrame(ctx, parent_section);
+
+            PromiseResult promise_result = ExpandPromise(ctx, pp, KeepAgentPromise, NULL);
+            result = PromiseResultUpdate(result, promise_result);
+            if (EvalAborted(ctx) || BundleAbort(ctx))
+            {
+                EvalContextStackPopFrame(ctx);
+                NoteBundleCompliance(bp, save_pr_kept, save_pr_repaired, save_pr_notkept, start);
+                SeqDestroy(promise_sequence);
+                return result;
+            }
+            EvalContextStackPopFrame(ctx);
+        }
+    }
+
+    NoteBundleCompliance(bp, save_pr_kept, save_pr_repaired, save_pr_notkept, start);
+    SeqDestroy(promise_sequence);
+    return result;
+}
+
 /*********************************************************************/
 
 #ifdef __MINGW32__

libpromises/cf3.defs.h

@@ -441,6 +441,7 @@ typedef enum
     COMMON_CONTROL_TLS_MIN_VERSION,
     COMMON_CONTROL_PACKAGE_INVENTORY,
     COMMON_CONTROL_PACKAGE_MODULE,
+    COMMON_CONTROL_EVALUATION_ORDER,
     COMMON_CONTROL_MAX
 } CommonControl;
 

libpromises/eval_context.h

@@ -108,6 +108,7 @@ typedef enum
 
     EVAL_OPTION_EVAL_FUNCTIONS = 1 << 0,
     EVAL_OPTION_CACHE_SYSTEM_FUNCTIONS = 1 << 1,
+    EVAL_OPTION_NORMAL_EVALUATION = 1 << 2,
 
     EVAL_OPTION_FULL = 0xFFFFFFFF
 } EvalContextOption;

libpromises/expand.c

@@ -1025,6 +1025,15 @@ static void ResolveControlBody(EvalContext *ctx, GenericAgentConfig *config,
             /* Ignored */
         }
 
+        if (strcmp(lval, CFG_CONTROLBODY[COMMON_CONTROL_EVALUATION_ORDER].lval) == 0)
+        {
+            Log(LOG_LEVEL_VERBOSE, "SET evaluation %s",
+                RvalScalarValue(evaluated_rval));
+
+            bool is_normal = (StringEqual(RvalScalarValue(evaluated_rval), "normal"));
+            EvalContextSetEvalOption(ctx, EVAL_OPTION_NORMAL_EVALUATION, is_normal);
+        }
+
         RvalDestroy(evaluated_rval);
     }
 

libpromises/mod_common.c

@@ -268,6 +268,7 @@ const ConstraintSyntax CFG_CONTROLBODY[COMMON_CONTROL_MAX + 1] =
     ConstraintSyntaxNewString("tls_min_version", "", "Minimum acceptable TLS version for outgoing connections, defaults to OpenSSL's default", SYNTAX_STATUS_NORMAL),
     ConstraintSyntaxNewStringList("package_inventory", ".*", "Name of the package manager used for software inventory management", SYNTAX_STATUS_NORMAL),
     ConstraintSyntaxNewString("package_module", ".*", "Name of the default package manager", SYNTAX_STATUS_NORMAL),
+    ConstraintSyntaxNewString("evaluation_order", "(normal|top_down)", "Order of evaluation of promises", SYNTAX_STATUS_NORMAL),
     ConstraintSyntaxNewNull()
 };
 

libpromises/policy.c

@@ -1437,6 +1437,7 @@ Promise *BundleSectionAppendPromise(BundleSection *section, const char *promiser
 {
     assert(promiser && "Missing promiser");
     assert(section != NULL && "Missing promise type");
+    assert(section->parent_bundle != NULL);
 
     Promise *pp = xcalloc(1, sizeof(Promise));
 

libpromises/prototypes3.h

@@ -44,6 +44,8 @@ void yyerror(const char *s);
 /* agent.c */
 
 PromiseResult ScheduleAgentOperations(EvalContext *ctx, const Bundle *bp);
+PromiseResult ScheduleAgentOperationsNormalOrder(EvalContext *ctx, const Bundle *bp);
+PromiseResult ScheduleAgentOperationsTopDownOrder(EvalContext *ctx, const Bundle *bp);
 
 /* Only for agent.c */