diff --git a/launcher.c b/launcher.c
index 4b71272..6109dcc 100644
--- a/launcher.c
+++ b/launcher.c
@@ -23,6 +23,7 @@ void print_help(char *self) {
     LOG_WARN("  --memory_limit     memory limit in MB");
     LOG_WARN("  --nproc_limit      number of processes limit");
     LOG_WARN("  --time_limit       time limit in ms");
+    LOG_WARN("  --fsize_limit      write file size limit in MB");
     LOG_WARN("  --sandbox_template sandbox template");
     LOG_WARN("  --sandbox_action   sandbox action");
     LOG_WARN("  --uid              user id");
@@ -40,6 +41,7 @@ void parse(int argc, char *argv[]) {
         [CFG_MEMORY_LIMIT]     = {"memory_limit",     required_argument, NULL, 0},
         [CFG_NPROC_LIMIT]      = {"nproc_limit",      required_argument, NULL, 0},
         [CFG_TIME_LIMIT]       = {"time_limit",       required_argument, NULL, 0},
+        [CFG_FSIZE_LIMIT]      = {"fsize_limit",      required_argument, NULL, 0},
         [CFG_SANDBOX_TEMPLATE] = {"sandbox_template", required_argument, NULL, 0},
         [CFG_SANDBOX_ACTION]   = {"sandbox_action",   required_argument, NULL, 0},
         [CFG_UID]              = {"uid",              optional_argument, NULL, 0},
@@ -57,9 +59,10 @@ void parse(int argc, char *argv[]) {
     while ((c = getopt_long_only(argc, argv, "", options, &idx)) != -1) {
         if (c != 0) break;
 
-        if (idx < CFG_IS_VALID)
+        if (idx < CFG_IS_VALID) {
             config[idx] = optarg;
-        else if (idx == CFG_IS_VALID) {
+            LOG_INFO("c = %d, x = %d, optarg = %s", c, idx, optarg);
+        } else if (idx == CFG_IS_VALID) {
             print_help(argv[0]);
             exit(0);
         }
diff --git a/launcher.h b/launcher.h
index 0dc3eb8..906f161 100644
--- a/launcher.h
+++ b/launcher.h
@@ -5,6 +5,7 @@ enum ConfigIndex {
     CFG_MEMORY_LIMIT = 0,
     CFG_NPROC_LIMIT,
     CFG_TIME_LIMIT,
+    CFG_FSIZE_LIMIT,
     CFG_SANDBOX_TEMPLATE,
     CFG_SANDBOX_ACTION,
     CFG_UID,
diff --git a/library.c b/library.c
index 3a3c891..2c00948 100644
--- a/library.c
+++ b/library.c
@@ -27,6 +27,7 @@ void setup_all(void) {
         config[CFG_MEMORY_LIMIT] = getenv(LIMIT_MEMORY);
         config[CFG_NPROC_LIMIT]  = getenv(LIMIT_NPROC);
         config[CFG_TIME_LIMIT]   = getenv(LIMIT_TIME);
+        config[CFG_FSIZE_LIMIT]  = getenv(LIMIT_FSIZE);
 
         config[CFG_SANDBOX_TEMPLATE] = getenv(SANDBOX_TEMPLATE);
         config[CFG_SANDBOX_ACTION]   = getenv(SANDBOX_ACTION);
diff --git a/resource.c b/resource.c
index 59635ab..c9629fa 100644
--- a/resource.c
+++ b/resource.c
@@ -21,12 +21,13 @@ void setup_rlimit(char *config[CFG_IS_VALID + 1]) {
 
     char *mem_limit_str   = config[CFG_MEMORY_LIMIT]; // in mb
     char *nproc_limit_str = config[CFG_NPROC_LIMIT];
-    char *time_limit_str  = config[CFG_TIME_LIMIT]; // in ms
+    char *time_limit_str  = config[CFG_TIME_LIMIT];  // in ms
+    char *fsize_limit_str = config[CFG_FSIZE_LIMIT]; // in mb
 
-    long mem_limit = 0, nproc_limit = 0, time_limit = 0;
+    long mem_limit = 0, nproc_limit = 0, time_limit = 0, fsize_limit = 0;
 
     if (mem_limit_str) {
-        // convert to bytes and double the memory limit
+        // convert to bytes
         mem_limit = strtol(mem_limit_str, NULL, 10) * 1024 * 1024;
     }
 
@@ -39,7 +40,15 @@ void setup_rlimit(char *config[CFG_IS_VALID + 1]) {
         time_limit = limit ? (limit + 1000) / 1000 : 0;
     }
 
+    if (fsize_limit_str) {
+        // convert to bytes
+        fsize_limit = strtol(fsize_limit_str, NULL, 10) * 1024 * 1024;
+    }
+
     SET_LIMIT(RLIMIT_AS, mem_limit, "memory", "bytes");
     SET_LIMIT(RLIMIT_NPROC, nproc_limit, "nproc", "processes"); // per user, **not** subprocess
     SET_LIMIT(RLIMIT_CPU, time_limit, "time", "seconds");       // except blocked time
+    SET_LIMIT(RLIMIT_FSIZE, fsize_limit, "fsize", "bytes");
+
+    SET_LIMIT(RLIMIT_CORE, 0, "coredump", "bytes"); // disable core dump
 }
diff --git a/resource.h b/resource.h
index 25cf6a1..d2b4161 100644
--- a/resource.h
+++ b/resource.h
@@ -7,6 +7,7 @@
 #define LIMIT_MEMORY "LIMIT_MEMORY"
 #define LIMIT_TIME   "LIMIT_TIME"
 #define LIMIT_NPROC  "LIMIT_NPROC"
+#define LIMIT_FSIZE  "LIMIT_FSIZE"
 
 void setup_rlimit(char *config[CFG_IS_VALID + 1]);
 
diff --git a/test.c b/test.c
index 148ca67..ece0712 100644
--- a/test.c
+++ b/test.c
@@ -64,6 +64,23 @@ void do_nproc() {
     }
 }
 
+void do_fsize() {
+    FILE *fp = fopen("test.dat", "w");
+    if (fp == NULL) {
+        LOG_ERR("FAIL: fopen failed");
+        return;
+    }
+
+    for (int i = 0; i < 1 << 30; i++) {
+        if (fputc('a', fp) == EOF) {
+            LOG_INFO("OK: fputc failed: i=%d", i);
+            break;
+        }
+    }
+
+    fclose(fp);
+}
+
 #pragma GCC pop_options
 
 int main() {
@@ -79,6 +96,7 @@ int main() {
         case 6: LOG_AND_EXECUTE(block1); break;
         case 7: LOG_AND_EXECUTE(block2); break;
         case 8: LOG_AND_EXECUTE(nproc); break;
+        case 9: LOG_AND_EXECUTE(fsize); break;
         default: {
             LOG_INFO("NO TEST SPECIFIED");
             break;