Exit on time (#904)

* Variable AFL_EXIT_ON_TIME description has been added.
Variables AFL_EXIT_ON_TIME and afl_exit_on_time has been added.
afl->exit_on_time variable initialization has been added.
The asignment of a value to the afl->afl_env.afl_exit_on_time variable from
environment variables has been added.
Code to exit on timeout if new path not found has been added.

* Type of afl_exit_on_time variable has been changed.
Variable exit_on_time has been added to the afl_state_t structure.

* Command `export AFL_EXIT_WHEN_DONE=1` has been added.

* Millisecond to second conversion has been added.
Call get_cur_time() has been added.

* Revert to using the saved current time value.

* Useless check has been removed.

3 files changed, 26 insertions, 0 deletions

diff --git a/src/afl-fuzz-state.c b/src/afl-fuzz-state.c
index 28d3339a..73ba7a52 100644
--- a/src/afl-fuzz-state.c
+++ b/src/afl-fuzz-state.c
@@ -99,6 +99,7 @@ void afl_state_init(afl_state_t *afl, uint32_t map_size) {
   afl->cal_cycles = CAL_CYCLES;
   afl->cal_cycles_long = CAL_CYCLES_LONG;
   afl->hang_tmout = EXEC_TIMEOUT;
+  afl->exit_on_time = 0;
   afl->stats_update_freq = 1;
   afl->stats_avg_exec = 0;
   afl->skip_deterministic = 1;
@@ -187,6 +188,13 @@ void read_afl_environment(afl_state_t *afl, char **envp) {
             afl->afl_env.afl_exit_when_done =
                 get_afl_env(afl_environment_variables[i]) ? 1 : 0;
 
+          } else if (!strncmp(env, "AFL_EXIT_ON_TIME",
+
+                              afl_environment_variable_len)) {
+
+            afl->afl_env.afl_exit_on_time =
+                (u8 *) get_afl_env(afl_environment_variables[i]);
+
           } else if (!strncmp(env, "AFL_NO_AFFINITY",
 
                               afl_environment_variable_len)) {
diff --git a/src/afl-fuzz-stats.c b/src/afl-fuzz-stats.c
index fd9af5e4..ee8bd2da 100644
--- a/src/afl-fuzz-stats.c
+++ b/src/afl-fuzz-stats.c
@@ -574,6 +574,16 @@ void show_stats(afl_state_t *afl) {
 
   }
 
+  /* AFL_EXIT_ON_TIME. */ 
+
+  if (unlikely(afl->last_path_time && !afl->non_instrumented_mode && 
+    afl->afl_env.afl_exit_on_time && 
+    (cur_ms - afl->last_path_time) > afl->exit_on_time)) {
+
+    afl->stop_soon = 2;
+
+  }
+
   if (unlikely(afl->total_crashes && afl->afl_env.afl_bench_until_crash)) {
 
     afl->stop_soon = 2;
diff --git a/src/afl-fuzz.c b/src/afl-fuzz.c
index 8c3ba575..8de3ed6b 100644
--- a/src/afl-fuzz.c
+++ b/src/afl-fuzz.c
@@ -204,6 +204,7 @@ static void usage(u8 *argv0, int more_help) {
       "AFL_DISABLE_TRIM: disable the trimming of test cases\n"
       "AFL_DUMB_FORKSRV: use fork server without feedback from target\n"
       "AFL_EXIT_WHEN_DONE: exit when all inputs are run and no new finds are found\n"
+      "AFL_EXIT_ON_TIME: exit when no new paths are found within the specified time period\n"
       "AFL_EXPAND_HAVOC_NOW: immediately enable expand havoc mode (default: after 60 minutes and a cycle without finds)\n"
       "AFL_FAST_CAL: limit the calibration stage to three cycles for speedup\n"
       "AFL_FORCE_UI: force showing the status screen (for virtual consoles)\n"
@@ -1246,6 +1247,13 @@ int main(int argc, char **argv_orig, char **envp) {
 
   }
 
+  if (afl->afl_env.afl_exit_on_time) {
+
+    u64 exit_on_time = atoi(afl->afl_env.afl_exit_on_time);
+    afl->exit_on_time = (u64)exit_on_time * 1000;
+
+  }
+
   if (afl->afl_env.afl_max_det_extras) {
 
     s32 max_det_extras = atoi(afl->afl_env.afl_max_det_extras);