feat: add infinite loop control args

include/vm/fzl_vm.h

@@ -36,7 +36,7 @@ typedef struct
 fzl_vm_t *fzl_mkvm(const char *filepath);
 
 // Load and run code
-int fzl_vm_run(fzl_vm_t *vm);
+int fzl_vm_run(fzl_vm_t *vm, bool allow_infinite, uint64_t max_iter);
 
 // Get last VM error message
 char *fzl_vm_geterror();

src/vm/fzl_vm.c

@@ -14,10 +14,7 @@
 #include <vm/fzl_vm_object.h>
 
 char last_err[256];
-size_t last_jmp_ip = 0;
-
-// NOTE: add `--max-iter` option for limit
-size_t max_iter_limit    = 100000;
+size_t last_jmp_ip       = 0;
 size_t total_jmp_on_same = 0;
 
 static char *expect_hdr = "FZL\0\1";
@@ -279,7 +276,7 @@ void print_err_data(fzl_vm_t *vm)
     printf("\t> [%zd] %lu\n", i, vm->cstack[i]);
 }
 
-int fzl_vm_run(fzl_vm_t *vm)
+int fzl_vm_run(fzl_vm_t *vm, bool allow_infinite, uint64_t max_iter)
 {
   if (!vm)
   {
@@ -673,19 +670,24 @@ int fzl_vm_run(fzl_vm_t *vm)
                    "runtime error - expected JMP addr");
           return -1;
         }
-        uint64_t jmp_ip = vm->ops[++vm->ip];
-        if (jmp_ip == last_jmp_ip)
-          total_jmp_on_same++;
-        else
-          total_jmp_on_same = 0;
 
-        if (total_jmp_on_same > max_iter_limit)
+        uint64_t jmp_ip = vm->ops[++vm->ip];
+        if (!allow_infinite)
         {
-          snprintf(last_err, sizeof(last_err),
-                   "runtime error - exceeded max loop jumps (infinite loop?)\n"
-                   "If you thinks there's mistake, change jumps limit with "
-                   "--max-iter=N");
-          return -1;
+          if (jmp_ip == last_jmp_ip)
+            total_jmp_on_same++;
+          else
+            total_jmp_on_same = 0;
+
+          if (total_jmp_on_same > max_iter)
+          {
+            snprintf(
+                last_err, sizeof(last_err),
+                "runtime error - exceeded max loop jumps (infinite loop?)\n"
+                "If you thinks there's mistake, change jumps limit with "
+                "--max-iter=N");
+            return -1;
+          }
         }
 
         vm->ip      = jmp_ip - 1;

src/vm/main.c

@@ -1,5 +1,7 @@
+#include <common/fzl_colors.h>
 #include <stdbool.h>
 #include <stddef.h>
+#include <stdint.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
@@ -10,14 +12,18 @@ typedef struct
   char *filepath;
   bool help;
   bool debug;
+  bool allow_infinite;
+  uint64_t max_iter;
 } run_args_t;
 
 void print_hint()
 {
   printf("Usage: fz [flags] <file path>\n");
   printf("Flags:\n");
-  printf("\t-h\t--help\tprint usage information\n");
-  printf("\t-d\t--debug\tdisplay program opcodes\n");
+  printf("\t-h\t--help\t\t\tprint usage information\n");
+  printf("\t-d\t--debug\t\t\tdisplay program opcodes\n");
+  printf("\t\t--allow-infinite\tallow infinite loops\n");
+  printf("\t\t--max-iter N\t\trestrict loops to maximum N iterations\n");
 }
 
 // Parse passed arguments and build args setup structure
@@ -29,10 +35,12 @@ run_args_t *parse_args(int argc, char **argv)
     return NULL;
   }
 
-  run_args_t *args = malloc(sizeof(run_args_t));
-  args->filepath   = NULL;
-  args->help       = false;
-  args->debug      = false;
+  run_args_t *args     = malloc(sizeof(run_args_t));
+  args->filepath       = NULL;
+  args->help           = false;
+  args->debug          = false;
+  args->allow_infinite = false;
+  args->max_iter       = 100000;
 
   for (int i = 0; i < argc; i++)
   {
@@ -46,9 +54,33 @@ run_args_t *parse_args(int argc, char **argv)
     }
     else if (strcmp(argv[i], "-d") == 0 || strcmp(argv[i], "--debug") == 0)
       args->debug = true;
+    else if (strcmp(argv[i], "--allow-infinite") == 0)
+      args->allow_infinite = true;
+    else if (strcmp(argv[i], "--max-iter") == 0)
+    {
+      char *n = argv[++i];
+      if (!n || argc <= i || !(n[0] >= '0' && n[0] <= '9'))
+      {
+        printf("%sError%s: --max-iter options requires number after it\n",
+               FZL_CERROR, FZL_CRST);
+        free(args);
+        return NULL;
+      }
+
+      uint64_t iters = strtol(n, NULL, 10);
+      if (iters < 1)
+      {
+        printf("%sError%s: '--max-iter 0' is not allowed\n", FZL_CERROR,
+               FZL_CRST);
+        free(args);
+        return NULL;
+      }
+
+      args->max_iter = iters;
+    }
     else
     {
-      printf("Error: unknown flag '%s'.\n", argv[i]);
+      printf("%sError%s: unknown flag '%s'.\n", FZL_CERROR, FZL_CRST, argv[i]);
       printf("Use 'fz --help' to read the usage\n");
       free(args);
       return NULL;
@@ -57,7 +89,8 @@ run_args_t *parse_args(int argc, char **argv)
 
   if (argv[argc - 1][0] == '-')
   {
-    printf("Error: last argument MUST be a file path\n");
+    printf("%sError%s: last argument MUST be a file path\n", FZL_CERROR,
+           FZL_CRST);
     printf("Use 'fz --help' for help\n");
     free(args);
     return NULL;
@@ -83,7 +116,7 @@ int main(int argc, char **argv)
   fzl_vm_t *vm = fzl_mkvm(args->filepath);
   if (!vm)
   {
-    printf("Error: %s\n", fzl_vm_geterror());
+    printf("%sError%s: %s\n", FZL_CERROR, FZL_CRST, fzl_vm_geterror());
     free(args);
     return -1;
   }
@@ -92,12 +125,12 @@ int main(int argc, char **argv)
     fzl_vm_print_ops(vm);
   else
   {
-    int result = fzl_vm_run(vm);
+    int result = fzl_vm_run(vm, args->allow_infinite, args->max_iter);
     if (result != 0)
     {
       char *err = fzl_vm_geterror();
       if (err && err[0])
-        printf("Error: %s\n", err);
+        printf("%sError%s: %s\n", FZL_CERROR, FZL_CRST, err);
 
       free(args);
       fzl_freevm(vm);