Merge 390be10 into 0014f29

test_framework/test_jit.py

@@ -49,6 +49,10 @@ def check_datafile(filename):
             cmd = [VM]
             if memfile:
                 cmd.extend(['-m', memfile.name])
+            if 'reload' in data:
+                cmd.extend(['-R'])
+            if 'unload' in data:
+                cmd.extend(['-u'])
             cmd.extend(['-j', '-r', str(register_offset), '-'])
 
             vm = Popen(cmd, stdin=PIPE, stdout=PIPE, stderr=PIPE)

test_framework/test_vm.py

@@ -34,6 +34,10 @@ def check_datafile(filename):
         memfile.write(data['mem'])
         memfile.flush()
         cmd.extend(['-m', memfile.name])
+    if 'reload' in data:
+        cmd.extend(['-R'])
+    if 'unload' in data:
+        cmd.extend(['-u'])
 
     cmd.append('-')
 

tests/reload.data

@@ -0,0 +1,6 @@
+-- reload
+-- asm
+mov r0, 0
+exit
+-- error
+Failed to load code: code has already been loaded into this VM. Use ubpf_unload_code() if you need to reuse this VM

tests/unload_reload.data

@@ -0,0 +1,6 @@
+-- unload
+-- asm
+mov r0, 0
+exit
+-- result
+0x0

vm/inc/ubpf.h

@@ -63,6 +63,17 @@ int ubpf_register(struct ubpf_vm *vm, unsigned int idx, const char *name, void *
  */
 int ubpf_load(struct ubpf_vm *vm, const void *code, uint32_t code_len, char **errmsg);
 
+/*
+ * Unload code from a VM
+ *
+ * This must be done before calling ubpf_load or ubpf_load_elf, except for the
+ * first time those functions are called. It clears the VM instructions to
+ * allow for new code to be loaded.
+ *
+ * It does not unregister any external functions.
+ */
+void ubpf_unload_code(struct ubpf_vm *vm);
+
 /*
  * Load code from an ELF file
  *

vm/test.c

@@ -40,6 +40,8 @@ static void usage(const char *name)
     fprintf(stderr, "If --jit is given then the JIT compiler will be used.\n");
     fprintf(stderr, "\nOther options:\n");
     fprintf(stderr, "  -r, --register-offset NUM: Change the mapping from eBPF to x86 registers\n");
+    fprintf(stderr, "  -u, --unload: unload the code and reload it (for testing only)\n");
+    fprintf(stderr, "  -R, --reload: reload the code, without unloading it first (for testing only, this should fail)\n");
 }
 
 int main(int argc, char **argv)
@@ -49,14 +51,18 @@ int main(int argc, char **argv)
         { .name = "mem", .val = 'm', .has_arg=1 },
         { .name = "jit", .val = 'j' },
         { .name = "register-offset", .val = 'r', .has_arg=1 },
+        { .name = "unload", .val = 'u' }, /* for unit test only */
+        { .name = "reload", .val = 'R' }, /* for unit test only */
         { }
     };
 
     const char *mem_filename = NULL;
     bool jit = false;
+    bool unload_reload = false;
+    bool reload = false;
 
     int opt;
-    while ((opt = getopt_long(argc, argv, "hm:jr:", longopts, NULL)) != -1) {
+    while ((opt = getopt_long(argc, argv, "hm:jr:uR", longopts, NULL)) != -1) {
         switch (opt) {
         case 'm':
             mem_filename = optarg;
@@ -70,12 +76,23 @@ int main(int argc, char **argv)
         case 'h':
             usage(argv[0]);
             return 0;
+        case 'u':
+            unload_reload = true;
+            break;
+        case 'R':
+            reload = true;
+            break;
         default:
             usage(argv[0]);
             return 1;
         }
     }
 
+    if (unload_reload && reload) {
+        fprintf(stderr, "-u and -R can not be used together\n");
+        return 1;
+    }
+
     if (argc != optind + 1) {
         usage(argv[0]);
         return 1;
@@ -113,11 +130,18 @@ int main(int argc, char **argv)
 
     char *errmsg;
     int rv;
+load:
     if (elf) {
 	rv = ubpf_load_elf(vm, code, code_len, &errmsg);
     } else {
 	rv = ubpf_load(vm, code, code_len, &errmsg);
     }
+    if (unload_reload || reload) {
+        if (unload_reload)
+            ubpf_unload_code(vm);
+        unload_reload = reload = false;
+        goto load;
+    }
 
     free(code);
 

vm/ubpf_vm.c

@@ -63,10 +63,7 @@ ubpf_create(void)
 void
 ubpf_destroy(struct ubpf_vm *vm)
 {
-    if (vm->jitted) {
-        munmap(vm->jitted, vm->jitted_size);
-    }
-    free(vm->insts);
+    ubpf_unload_code(vm);
     free(vm->ext_funcs);
     free(vm->ext_func_names);
     free(vm);
@@ -103,7 +100,7 @@ ubpf_load(struct ubpf_vm *vm, const void *code, uint32_t code_len, char **errmsg
     *errmsg = NULL;
 
     if (vm->insts) {
-        *errmsg = ubpf_error("code has already been loaded into this VM");
+        *errmsg = ubpf_error("code has already been loaded into this VM. Use ubpf_unload_code() if you need to reuse this VM");
         return -1;
     }
 
@@ -128,6 +125,21 @@ ubpf_load(struct ubpf_vm *vm, const void *code, uint32_t code_len, char **errmsg
     return 0;
 }
 
+void
+ubpf_unload_code(struct ubpf_vm *vm)
+{
+    if (vm->jitted) {
+        munmap(vm->jitted, vm->jitted_size);
+        vm->jitted = NULL;
+        vm->jitted_size = 0;
+    }
+    if (vm->insts) {
+        free(vm->insts);
+        vm->insts = NULL;
+        vm->num_insts = 0;
+    }
+}
+
 static uint32_t
 u32(uint64_t x)
 {