done implementing AFL_MAP_SIZE

docs/env_variables.md

@@ -243,6 +243,11 @@ checks or alter some of the more exotic semantics of the tool:
     normally indicated by the cycle counter in the UI turning green. May be
     convenient for some types of automated jobs.
 
+  - AFL_MAP_SIZE sets the size of the shared map that afl-fuzz, afl-showmap,
+    afl-tmin and afl-analyze create to gather instrumentation data from
+    the target. This must be equal or larger than the size the target was
+    compiled with.
+
   - Setting AFL_NO_AFFINITY disables attempts to bind to a specific CPU core
     on Linux systems. This slows things down, but lets you run more instances
     of afl-fuzz than would be prudent (if you really want to).

gcc_plugin/afl-gcc-fast.c

@@ -364,6 +364,16 @@ int main(int argc, char **argv, char **envp) {
 
     be_quiet = 1;
 
+  u8 *ptr;
+  if (!be_quiet &&
+      ((ptr = getenv("AFL_MAP_SIZE")) || (ptr = getenv("AFL_MAPSIZE")))) {
+
+    u32 map_size = atoi(ptr);
+    if (map_size != MAP_SIZE)
+      FATAL("AFL_MAP_SIZE is not supported by afl-gcc-fast");
+
+  }
+
   check_environment_vars(envp);
 
   find_obj(argv[0]);

llvm_mode/afl-clang-fast.c

@@ -796,6 +796,16 @@ int main(int argc, char **argv, char **envp) {
 
   }
 
+  u8 *ptr2;
+  if (!be_quiet && instrument_mode != INSTRUMENT_LTO &&
+      ((ptr2 = getenv("AFL_MAP_SIZE")) || (ptr2 = getenv("AFL_MAPSIZE")))) {
+
+    u32 map_size = atoi(ptr2);
+    if (map_size != MAP_SIZE)
+      FATAL("AFL_MAP_SIZE is not supported by afl-clang-fast");
+
+  }
+
   if (debug) {
 
     SAYF(cMGN "[D]" cRST " cd \"%s\";", getthecwd());

llvm_mode/afl-llvm-lto-instrumentation.so.cc

@@ -608,20 +608,22 @@ bool AFLLTOPass::runOnModule(Module &M) {
 
     }
 
-    // save highest location ID to global variable
-    // do this after each function to fail faster
-    if (afl_global_id > MAP_SIZE) {
+  }
 
-      uint32_t pow2map = 1, map = afl_global_id;
-      while ((map = map >> 1))
-        pow2map++;
-      FATAL(
-          "We have %u blocks to instrument but the map size is only %u! Edit "
-          "config.h and set MAP_SIZE_POW2 from %u to %u, then recompile "
-          "afl-fuzz and llvm_mode.",
-          afl_global_id, MAP_SIZE, MAP_SIZE_POW2, pow2map);
+  // save highest location ID to global variable
+  // do this after each function to fail faster
+  if (!be_quiet && afl_global_id > MAP_SIZE) {
 
-    }
+    uint32_t pow2map = 1, map = afl_global_id;
+    while ((map = map >> 1))
+      pow2map++;
+    WARNF(
+        "We have %u blocks to instrument but the map size is only %u. Either "
+        "edit config.h and set MAP_SIZE_POW2 from %u to %u, then recompile "
+        "afl-fuzz and llvm_mode and then make this target - or set "
+        "AFL_MAP_SIZE with at least size %u when running afl-fuzz with this "
+        "target.",
+        afl_global_id, MAP_SIZE, MAP_SIZE_POW2, pow2map, afl_global_id);
 
   }
 

src/afl-gcc.c

@@ -412,7 +412,8 @@ int main(int argc, char **argv) {
   }
 
   u8 *ptr;
-  if ((ptr = getenv("AFL_MAP_SIZE")) || (ptr = getenv("AFL_MAPSIZE"))) {
+  if (!be_quiet &&
+      ((ptr = getenv("AFL_MAP_SIZE")) || (ptr = getenv("AFL_MAPSIZE")))) {
 
     u32 map_size = atoi(ptr);
     if (map_size != MAP_SIZE) FATAL("AFL_MAP_SIZE is not supported by afl-gcc");