text: /*
     american fuzzy lop++ - instrumentation bootstrap
     ------------------------------------------------
  
     Copyright 2015, 2016 Google Inc. All rights reserved.
     Copyright 2019-2020 AFLplusplus Project. All rights reserved.
  
     Licensed under the Apache License, Version 2.0 (the "License");
     you may not use this file except in compliance with the License.
     You may obtain a copy of the License at:
  
       http://www.apache.org/licenses/LICENSE-2.0
  
  
  */
  
  #ifdef __ANDROID__
    #include "android-ashmem.h"
  #endif
  #include "config.h"
  #include "types.h"
  #include "cmplog.h"
  #include "llvm-ngram-coverage.h"
  
  #include <stdio.h>
  #include <stdlib.h>
  #include <signal.h>
  #include <unistd.h>
  #include <string.h>
  #include <assert.h>
  #include <stdint.h>
  #include <stddef.h>
  #include <limits.h>
  #include <errno.h>
  
  #include <sys/mman.h>
  #ifndef __HAIKU__
    #include <sys/shm.h>
  #endif
  #include <sys/wait.h>
  #include <sys/types.h>
  
  #if !__GNUC__
    #include "llvm/Config/llvm-config.h"
  #endif
  
  #ifdef __linux__
    #include "snapshot-inl.h"
  #endif
  
  /* This is a somewhat ugly hack for the experimental 'trace-pc-guard' mode.
     Basically, we need to make sure that the forkserver is initialized after
     the LLVM-generated runtime initialization pass, not before. */
  
  #ifndef MAP_FIXED_NOREPLACE
    #ifdef MAP_EXCL
      #define MAP_FIXED_NOREPLACE MAP_EXCL | MAP_FIXED
    #else
      #define MAP_FIXED_NOREPLACE MAP_FIXED
    #endif
  #endif
  
  #define CTOR_PRIO 3
  
  #include <sys/mman.h>
  #include <fcntl.h>
  
  /* Globals needed by the injected instrumentation. The __afl_area_initial region
     is used for instrumentation output before __afl_map_shm() has a chance to
     run. It will end up as .comm, so it shouldn't be too wasteful. */
  
  #if MAP_SIZE <= 65536
    #define MAP_INITIAL_SIZE 256000
  #else
    #define MAP_INITIAL_SIZE MAP_SIZE
  #endif
  
  u8   __afl_area_initial[MAP_INITIAL_SIZE];
  u8 * __afl_area_ptr = __afl_area_initial;
  u8 * __afl_dictionary;
  u8 * __afl_fuzz_ptr;
  u32  __afl_fuzz_len_dummy;
  u32 *__afl_fuzz_len = &__afl_fuzz_len_dummy;
  
  u32 __afl_final_loc;
  u32 __afl_map_size = MAP_SIZE;
  u32 __afl_dictionary_len;
  u64 __afl_map_addr;
  
  #ifdef __ANDROID__
  PREV_LOC_T __afl_prev_loc[NGRAM_SIZE_MAX];
  u32        __afl_prev_ctx;
  u32        __afl_cmp_counter;
  #else
  __thread PREV_LOC_T __afl_prev_loc[NGRAM_SIZE_MAX];
  __thread u32        __afl_prev_ctx;
  __thread u32        __afl_cmp_counter;
  #endif
  
  int __afl_sharedmem_fuzzing __attribute__((weak));
  
  struct cmp_map *__afl_cmp_map;
  
  /* Child pid? */
  
  static s32 child_pid;
  static void (*old_sigterm_handler)(int) = 0;
  
  /* Running in persistent mode? */
  
  static u8 is_persistent;
  
  /* Are we in sancov mode? */
  
  static u8 _is_sancov;
  
  /* ensure we kill the child on termination */
  
  void at_exit(int signal) {
  
    if (child_pid > 0) { kill(child_pid, SIGKILL); }
  
  }
  
  /* Uninspired gcc plugin instrumentation */
  
  void __afl_trace(const u32 x) {
  
    PREV_LOC_T prev = __afl_prev_loc[0];
    __afl_prev_loc[0] = (x >> 1);
  
    u8 *p = &__afl_area_ptr[prev ^ x];
  
  #if 1                                      /* enable for neverZero feature. */
    #if __GNUC__
    u8 c = __builtin_add_overflow(*p, 1, p);
    *p += c;
    #else
    *p += 1 + ((u8)(1 + *p) == 0);
    #endif
  #else
    ++*p;
  #endif
  
    return;
  
  }
  
  /* Error reporting to forkserver controller */
  
  void send_forkserver_error(int error) {
  
    u32 status;
    if (!error || error > 0xffff) return;
    status = (FS_OPT_ERROR | FS_OPT_SET_ERROR(error));
    if (write(FORKSRV_FD + 1, (char *)&status, 4) != 4) return;
  
  }
  
  /* SHM fuzzing setup. */
  
  static void __afl_map_shm_fuzz() {
  
    char *id_str = getenv(SHM_FUZZ_ENV_VAR);
  
    if (getenv("AFL_DEBUG")) {
  
      fprintf(stderr, "DEBUG: fuzzcase shmem %s\n", id_str ? id_str : "none");
  
    }
  
    if (id_str) {
  
      u8 *map = NULL;
  
  #ifdef USEMMAP
      const char *shm_file_path = id_str;
      int         shm_fd = -1;
  
      /* create the shared memory segment as if it was a file */
      shm_fd = shm_open(shm_file_path, O_RDWR, 0600);
      if (shm_fd == -1) {
  
        fprintf(stderr, "shm_open() failed for fuzz\n");
        send_forkserver_error(FS_ERROR_SHM_OPEN);
        exit(1);
  
      }
  
      map =
          (u8 *)mmap(0, MAX_FILE + sizeof(u32), PROT_READ, MAP_SHARED, shm_fd, 0);
  
  #else
      u32 shm_id = atoi(id_str);
      map = (u8 *)shmat(shm_id, NULL, 0);
  
  #endif
  
      /* Whooooops. */
  
      if (!map || map == (void *)-1) {
  
        perror("Could not access fuzzing shared memory");
        send_forkserver_error(FS_ERROR_SHM_OPEN);
        exit(1);
  
      }
  
      __afl_fuzz_len = (u32 *)map;
      __afl_fuzz_ptr = map + sizeof(u32);
  
      if (getenv("AFL_DEBUG")) {
  
        fprintf(stderr, "DEBUG: successfully got fuzzing shared memory\n");
  
      }
  
    } else {
  
      fprintf(stderr, "Error: variable for fuzzing shared memory is not set\n");
      send_forkserver_error(FS_ERROR_SHM_OPEN);
      exit(1);
  
    }
  
  }
  
  /* SHM setup. */
  
  static void __afl_map_shm(void) {
  
    // if we are not running in afl ensure the map exists
    if (!__afl_area_ptr) { __afl_area_ptr = __afl_area_initial; }
  
    char *id_str = getenv(SHM_ENV_VAR);
  
    if (__afl_final_loc) {
  
      if (__afl_final_loc % 32)
        __afl_final_loc = (((__afl_final_loc + 31) >> 5) << 5);
      __afl_map_size = __afl_final_loc;
  
      if (__afl_final_loc > MAP_SIZE) {
  
        char *ptr;
        u32   val = 0;
        if ((ptr = getenv("AFL_MAP_SIZE")) != NULL) val = atoi(ptr);
        if (val < __afl_final_loc) {
  
          if (__afl_final_loc > FS_OPT_MAX_MAPSIZE) {
  
            if (!getenv("AFL_QUIET"))
              fprintf(stderr,
                      "Error: AFL++ tools *require* to set AFL_MAP_SIZE to %u "
                      "to be able to run this instrumented program!\n",
                      __afl_final_loc);
  
            if (id_str) {
  
              send_forkserver_error(FS_ERROR_MAP_SIZE);
              exit(-1);
  
            }
  
          } else {
  
            if (!getenv("AFL_QUIET"))
              fprintf(stderr,
                      "Warning: AFL++ tools will need to set AFL_MAP_SIZE to %u "
                      "to be able to run this instrumented program!\n",
                      __afl_final_loc);
  
          }
  
        }
  
      }
  
    }
  
    /* If we're running under AFL, attach to the appropriate region, replacing the
       early-stage __afl_area_initial region that is needed to allow some really
       hacky .init code to work correctly in projects such as OpenSSL. */
  
    if (getenv("AFL_DEBUG"))
      fprintf(stderr,
              "DEBUG: id_str %s, __afl_area_ptr %p, __afl_area_initial %p, "
              "__afl_map_addr 0x%llx, MAP_SIZE %u, __afl_final_loc %u, "
              "max_size_forkserver %u/0x%x\n",
              id_str == NULL ? "<null>" : id_str, __afl_area_ptr,
              __afl_area_initial, __afl_map_addr, MAP_SIZE, __afl_final_loc,
              FS_OPT_MAX_MAPSIZE, FS_OPT_MAX_MAPSIZE);
  
    if (id_str) {
  
      if (__afl_area_ptr && __afl_area_ptr != __afl_area_initial) {
  
        if (__afl_map_addr)
          munmap((void *)__afl_map_addr, __afl_final_loc);
        else
          free(__afl_area_ptr);
        __afl_area_ptr = __afl_area_initial;
  
      }
  
  #ifdef USEMMAP
      const char *   shm_file_path = id_str;
      int            shm_fd = -1;
      unsigned char *shm_base = NULL;
  
      /* create the shared memory segment as if it was a file */
      shm_fd = shm_open(shm_file_path, O_RDWR, 0600);
      if (shm_fd == -1) {
  
        fprintf(stderr, "shm_open() failed\n");
        send_forkserver_error(FS_ERROR_SHM_OPEN);
        exit(1);
  
      }
  
      /* map the shared memory segment to the address space of the process */
      if (__afl_map_addr) {
  
        shm_base =
            mmap((void *)__afl_map_addr, __afl_map_size, PROT_READ | PROT_WRITE,
                 MAP_FIXED_NOREPLACE | MAP_SHARED, shm_fd, 0);
  
      } else {
  
        shm_base = mmap(0, __afl_map_size, PROT_READ | PROT_WRITE, MAP_SHARED,
                        shm_fd, 0);
  
      }
  
      if (shm_base == MAP_FAILED) {
  
        close(shm_fd);
        shm_fd = -1;
  
        fprintf(stderr, "mmap() failed\n");
        if (__afl_map_addr)
          send_forkserver_error(FS_ERROR_MAP_ADDR);
        else
          send_forkserver_error(FS_ERROR_MMAP);
        perror("mmap for map");
  
        exit(2);
  
      }
  
      __afl_area_ptr = shm_base;
  #else
      u32 shm_id = atoi(id_str);
  
      __afl_area_ptr = shmat(shm_id, (void *)__afl_map_addr, 0);
  
      /* Whooooops. */
  
      if (!__afl_area_ptr || __afl_area_ptr == (void *)-1) {
  
        if (__afl_map_addr)
          send_forkserver_error(FS_ERROR_MAP_ADDR);
        else
          send_forkserver_error(FS_ERROR_SHMAT);
  
        perror("shmat for map");
        _exit(1);
  
      }
  
  #endif
  
      /* Write something into the bitmap so that even with low AFL_INST_RATIO,
         our parent doesn't give up on us. */
  
      __afl_area_ptr[0] = 1;
  
    } else if ((!__afl_area_ptr || __afl_area_ptr == __afl_area_initial) &&
  
               __afl_map_addr) {
  
      __afl_area_ptr =
          mmap((void *)__afl_map_addr, __afl_map_size, PROT_READ | PROT_WRITE,
               MAP_FIXED_NOREPLACE | MAP_SHARED | MAP_ANONYMOUS, -1, 0);
  
      if (__afl_area_ptr == MAP_FAILED) {
  
        fprintf(stderr, "can not acquire mmap for address %p\n",
                (void *)__afl_map_addr);
        send_forkserver_error(FS_ERROR_SHM_OPEN);
        exit(1);
  
      }
  
    } else if (_is_sancov && __afl_area_ptr != __afl_area_initial) {
  
      free(__afl_area_ptr);
      __afl_area_ptr = NULL;
      if (__afl_final_loc > MAP_INITIAL_SIZE)
        __afl_area_ptr = malloc(__afl_final_loc);
      if (!__afl_area_ptr) __afl_area_ptr = __afl_area_initial;
  
    }
  
    id_str = getenv(CMPLOG_SHM_ENV_VAR);
  
    if (getenv("AFL_DEBUG")) {
  
      fprintf(stderr, "DEBUG: cmplog id_str %s\n",
              id_str == NULL ? "<null>" : id_str);
  
    }
  
    if (id_str) {
  
  #ifdef USEMMAP
      const char *    shm_file_path = id_str;
      int             shm_fd = -1;
      struct cmp_map *shm_base = NULL;
  
      /* create the shared memory segment as if it was a file */
      shm_fd = shm_open(shm_file_path, O_RDWR, 0600);
      if (shm_fd == -1) {
  
        perror("shm_open() failed\n");
        send_forkserver_error(FS_ERROR_SHM_OPEN);
        exit(1);
  
      }
  
      /* map the shared memory segment to the address space of the process */
      shm_base = mmap(0, sizeof(struct cmp_map), PROT_READ | PROT_WRITE,
                      MAP_SHARED, shm_fd, 0);
      if (shm_base == MAP_FAILED) {
  
        close(shm_fd);
        shm_fd = -1;
  
        fprintf(stderr, "mmap() failed\n");
        send_forkserver_error(FS_ERROR_SHM_OPEN);
        exit(2);
  
      }
  
      __afl_cmp_map = shm_base;
  #else
      u32 shm_id = atoi(id_str);
  
      __afl_cmp_map = shmat(shm_id, NULL, 0);
  #endif
  
      if (!__afl_cmp_map || __afl_cmp_map == (void *)-1) {
  
        perror("shmat for cmplog");
        send_forkserver_error(FS_ERROR_SHM_OPEN);
        _exit(1);
  
      }
  
    }
  
  }
  
  #ifdef __linux__
  static void __afl_start_snapshots(void) {
  
    static u8 tmp[4] = {0, 0, 0, 0};
    u32       status = 0;
    u32       already_read_first = 0;
    u32       was_killed;
  
    u8 child_stopped = 0;
  
    void (*old_sigchld_handler)(int) = 0;  // = signal(SIGCHLD, SIG_DFL);
  
    /* Phone home and tell the parent that we're OK. If parent isn't there,
       assume we're not running in forkserver mode and just execute program. */
  
    status |= (FS_OPT_ENABLED | FS_OPT_SNAPSHOT);
    if (__afl_sharedmem_fuzzing != 0) status |= FS_OPT_SHDMEM_FUZZ;
    if (__afl_map_size <= FS_OPT_MAX_MAPSIZE)
      status |= (FS_OPT_SET_MAPSIZE(__afl_map_size) | FS_OPT_MAPSIZE);
    if (__afl_dictionary_len && __afl_dictionary) status |= FS_OPT_AUTODICT;
    memcpy(tmp, &status, 4);
  
    if (write(FORKSRV_FD + 1, tmp, 4) != 4) return;
  
    if (__afl_sharedmem_fuzzing || (__afl_dictionary_len && __afl_dictionary)) {
  
      if (read(FORKSRV_FD, &was_killed, 4) != 4) _exit(1);
  
      if (getenv("AFL_DEBUG")) {
  
        fprintf(stderr, "target forkserver recv: %08x\n", was_killed);
  
      }
  
      if ((was_killed & (FS_OPT_ENABLED | FS_OPT_SHDMEM_FUZZ)) ==
          (FS_OPT_ENABLED | FS_OPT_SHDMEM_FUZZ)) {
  
        __afl_map_shm_fuzz();
  
      }
  
      if ((was_killed & (FS_OPT_ENABLED | FS_OPT_AUTODICT)) ==
              (FS_OPT_ENABLED | FS_OPT_AUTODICT) &&
          __afl_dictionary_len && __afl_dictionary) {
  
        // great lets pass the dictionary through the forkserver FD
        u32 len = __afl_dictionary_len, offset = 0;
        s32 ret;
  
        if (write(FORKSRV_FD + 1, &len, 4) != 4) {
  
          write(2, "Error: could not send dictionary len\n",
                strlen("Error: could not send dictionary len\n"));
          _exit(1);
  
        }
  
        while (len != 0) {
  
          ret = write(FORKSRV_FD + 1, __afl_dictionary + offset, len);
  
          if (ret < 1) {
  
            write(2, "Error: could not send dictionary\n",
                  strlen("Error: could not send dictionary\n"));
            _exit(1);
  
          }
  
          len -= ret;
          offset += ret;
  
        }
  
      } else {
  
        // uh this forkserver does not understand extended option passing
        // or does not want the dictionary
        if (!__afl_fuzz_ptr) already_read_first = 1;
  
      }
  
    }
  
    while (1) {
  
      int status;
  
      if (already_read_first) {
  
        already_read_first = 0;
  
      } else {
  
        /* Wait for parent by reading from the pipe. Abort if read fails. */
        if (read(FORKSRV_FD, &was_killed, 4) != 4) _exit(1);
  
      }
  
    #ifdef _AFL_DOCUMENT_MUTATIONS
      if (__afl_fuzz_ptr) {
  
        static uint32_t counter = 0;
        char            fn[32];
        sprintf(fn, "%09u:forkserver", counter);
        s32 fd_doc = open(fn, O_WRONLY | O_CREAT | O_TRUNC, 0600);
        if (fd_doc >= 0) {
  
          if (write(fd_doc, __afl_fuzz_ptr, *__afl_fuzz_len) != *__afl_fuzz_len) {
  
            fprintf(stderr, "write of mutation file failed: %s\n", fn);
            unlink(fn);
  
          }
  
          close(fd_doc);
  
        }
  
        counter++;
  
      }
  
    #endif
  
      /* If we stopped the child in persistent mode, but there was a race
         condition and afl-fuzz already issued SIGKILL, write off the old
         process. */
  
      if (child_stopped && was_killed) {
  
        child_stopped = 0;
        if (waitpid(child_pid, &status, 0) < 0) _exit(1);
  
      }
  
      if (!child_stopped) {
  
        /* Once woken up, create a clone of our process. */
  
        child_pid = fork();
        if (child_pid < 0) _exit(1);
  
        /* In child process: close fds, resume execution. */
  
        if (!child_pid) {
  
          //(void)nice(-20);  // does not seem to improve
  
          signal(SIGCHLD, old_sigchld_handler);
          signal(SIGTERM, old_sigterm_handler);
  
          close(FORKSRV_FD);
          close(FORKSRV_FD + 1);
  
          if (!afl_snapshot_take(AFL_SNAPSHOT_MMAP | AFL_SNAPSHOT_FDS |
                                 AFL_SNAPSHOT_REGS | AFL_SNAPSHOT_EXIT)) {
  
            raise(SIGSTOP);
  
          }
  
          __afl_area_ptr[0] = 1;
          memset(__afl_prev_loc, 0, NGRAM_SIZE_MAX * sizeof(PREV_LOC_T));
  
          return;
  
        }
  
      } else {
  
        /* Special handling for persistent mode: if the child is alive but
           currently stopped, simply restart it with SIGCONT. */
  
        kill(child_pid, SIGCONT);
        child_stopped = 0;
  
      }
  
      /* In parent process: write PID to pipe, then wait for child. */
  
      if (write(FORKSRV_FD + 1, &child_pid, 4) != 4) _exit(1);
  
      if (waitpid(child_pid, &status, WUNTRACED) < 0) _exit(1);
  
      /* In persistent mode, the child stops itself with SIGSTOP to indicate
         a successful run. In this case, we want to wake it up without forking
         again. */
  
      if (WIFSTOPPED(status)) child_stopped = 1;
  
      /* Relay wait status to pipe, then loop back. */
  
      if (write(FORKSRV_FD + 1, &status, 4) != 4) _exit(1);
  
    }
  
  }
  
  #endif
  
  /* Fork server logic. */
  
  static void __afl_start_forkserver(void) {
  
    struct sigaction orig_action;
    sigaction(SIGTERM, NULL, &orig_action);
    old_sigterm_handler = orig_action.sa_handler;
    signal(SIGTERM, at_exit);
  
  #ifdef __linux__
    if (/*!is_persistent &&*/ !__afl_cmp_map && !getenv("AFL_NO_SNAPSHOT") &&
        afl_snapshot_init() >= 0) {
  
      __afl_start_snapshots();
      return;
  
    }
  
  #endif
  
    u8  tmp[4] = {0, 0, 0, 0};
    u32 status = 0;
    u32 already_read_first = 0;
    u32 was_killed;
  
    u8 child_stopped = 0;
  
    void (*old_sigchld_handler)(int) = 0;  // = signal(SIGCHLD, SIG_DFL);
  
    if (__afl_map_size <= FS_OPT_MAX_MAPSIZE)
      status |= (FS_OPT_SET_MAPSIZE(__afl_map_size) | FS_OPT_MAPSIZE);
    if (__afl_dictionary_len && __afl_dictionary) status |= FS_OPT_AUTODICT;
    if (__afl_sharedmem_fuzzing != 0) status |= FS_OPT_SHDMEM_FUZZ;
    if (status) status |= (FS_OPT_ENABLED);
    memcpy(tmp, &status, 4);
  
    /* Phone home and tell the parent that we're OK. If parent isn't there,
       assume we're not running in forkserver mode and just execute program. */
  
    if (write(FORKSRV_FD + 1, tmp, 4) != 4) return;
  
    if (__afl_sharedmem_fuzzing || (__afl_dictionary_len && __afl_dictionary)) {
  
      if (read(FORKSRV_FD, &was_killed, 4) != 4) _exit(1);
  
      if (getenv("AFL_DEBUG")) {
  
        fprintf(stderr, "target forkserver recv: %08x\n", was_killed);
  
      }
  
      if ((was_killed & (FS_OPT_ENABLED | FS_OPT_SHDMEM_FUZZ)) ==
          (FS_OPT_ENABLED | FS_OPT_SHDMEM_FUZZ)) {
  
        __afl_map_shm_fuzz();
  
      }
  
      if ((was_killed & (FS_OPT_ENABLED | FS_OPT_AUTODICT)) ==
              (FS_OPT_ENABLED | FS_OPT_AUTODICT) &&
          __afl_dictionary_len && __afl_dictionary) {
  
        // great lets pass the dictionary through the forkserver FD
        u32 len = __afl_dictionary_len, offset = 0;
        s32 ret;
  
        if (write(FORKSRV_FD + 1, &len, 4) != 4) {
  
          write(2, "Error: could not send dictionary len\n",
                strlen("Error: could not send dictionary len\n"));
          _exit(1);
  
        }
  
        while (len != 0) {
  
          ret = write(FORKSRV_FD + 1, __afl_dictionary + offset, len);
  
          if (ret < 1) {
  
            write(2, "Error: could not send dictionary\n",
                  strlen("Error: could not send dictionary\n"));
            _exit(1);
  
          }
  
          len -= ret;
          offset += ret;
  
        }
  
      } else {
  
        // uh this forkserver does not understand extended option passing
        // or does not want the dictionary
        if (!__afl_fuzz_ptr) already_read_first = 1;
  
      }
  
    }
  
    while (1) {
  
      int status;
  
      /* Wait for parent by reading from the pipe. Abort if read fails. */
  
      if (already_read_first) {
  
        already_read_first = 0;
  
      } else {
  
        if (read(FORKSRV_FD, &was_killed, 4) != 4) _exit(1);
  
      }
  
  #ifdef _AFL_DOCUMENT_MUTATIONS
      if (__afl_fuzz_ptr) {
  
        static uint32_t counter = 0;
        char            fn[32];
        sprintf(fn, "%09u:forkserver", counter);
        s32 fd_doc = open(fn, O_WRONLY | O_CREAT | O_TRUNC, 0600);
        if (fd_doc >= 0) {
  
          if (write(fd_doc, __afl_fuzz_ptr, *__afl_fuzz_len) != *__afl_fuzz_len) {
  
            fprintf(stderr, "write of mutation file failed: %s\n", fn);
            unlink(fn);
  
          }
  
          close(fd_doc);
  
        }
  
        counter++;
  
      }
  
  #endif
  
      /* If we stopped the child in persistent mode, but there was a race
         condition and afl-fuzz already issued SIGKILL, write off the old
         process. */
  
      if (child_stopped && was_killed) {
  
        child_stopped = 0;
        if (waitpid(child_pid, &status, 0) < 0) _exit(1);
  
      }
  
      if (!child_stopped) {
  
        /* Once woken up, create a clone of our process. */
  
        child_pid = fork();
        if (child_pid < 0) _exit(1);
  
        /* In child process: close fds, resume execution. */
  
        if (!child_pid) {
  
          //(void)nice(-20);
  
          signal(SIGCHLD, old_sigchld_handler);
          signal(SIGTERM, old_sigterm_handler);
  
          close(FORKSRV_FD);
          close(FORKSRV_FD + 1);
          return;
  
        }
  
      } else {
  
        /* Special handling for persistent mode: if the child is alive but
           currently stopped, simply restart it with SIGCONT. */
  
        kill(child_pid, SIGCONT);
        child_stopped = 0;
  
      }
  
      /* In parent process: write PID to pipe, then wait for child. */
  
      if (write(FORKSRV_FD + 1, &child_pid, 4) != 4) _exit(1);
  
      if (waitpid(child_pid, &status, is_persistent ? WUNTRACED : 0) < 0)
        _exit(1);
  
      /* In persistent mode, the child stops itself with SIGSTOP to indicate
         a successful run. In this case, we want to wake it up without forking
         again. */
  
      if (WIFSTOPPED(status)) child_stopped = 1;
  
      /* Relay wait status to pipe, then loop back. */
  
      if (write(FORKSRV_FD + 1, &status, 4) != 4) _exit(1);
  
    }
  
  }
  
  /* A simplified persistent mode handler, used as explained in
   * README.llvm.md. */
  
  int __afl_persistent_loop(unsigned int max_cnt) {
  
    static u8  first_pass = 1;
    static u32 cycle_cnt;
  
    if (first_pass) {
  
      /* Make sure that every iteration of __AFL_LOOP() starts with a clean slate.
         On subsequent calls, the parent will take care of that, but on the first
         iteration, it's our job to erase any trace of whatever happened
         before the loop. */
  
      if (is_persistent) {
  
        memset(__afl_area_ptr, 0, __afl_map_size);
        __afl_area_ptr[0] = 1;
        memset(__afl_prev_loc, 0, NGRAM_SIZE_MAX * sizeof(PREV_LOC_T));
  
      }
  
      cycle_cnt = max_cnt;
      first_pass = 0;
      return 1;
  
    }
  
    if (is_persistent) {
  
      if (--cycle_cnt) {
  
        raise(SIGSTOP);
  
        __afl_area_ptr[0] = 1;
        memset(__afl_prev_loc, 0, NGRAM_SIZE_MAX * sizeof(PREV_LOC_T));
  
        return 1;
  
      } else {
  
        /* When exiting __AFL_LOOP(), make sure that the subsequent code that
           follows the loop is not traced. We do that by pivoting back to the
           dummy output region. */
  
        __afl_area_ptr = __afl_area_initial;
  
      }
  
    }
  
    return 0;
  
  }
  
  /* This one can be called from user code when deferred forkserver mode
      is enabled. */
  
  void __afl_manual_init(void) {
  
    static u8 init_done;
  
    if (getenv("AFL_DISABLE_LLVM_INSTRUMENTATION")) {
  
      init_done = 1;
      is_persistent = 0;
      __afl_sharedmem_fuzzing = 0;
      if (__afl_area_ptr == NULL) __afl_area_ptr = __afl_area_initial;
  
      if (getenv("AFL_DEBUG"))
        fprintf(stderr,
                "DEBUG: disabled instrumentation because of "
                "AFL_DISABLE_LLVM_INSTRUMENTATION\n");
  
    }
  
    if (!init_done) {
  
      __afl_start_forkserver();
      init_done = 1;
  
    }
  
  }
  
  /* Initialization of the forkserver - latest possible */
  
  __attribute__((constructor())) void __afl_auto_init(void) {
  
    if (getenv("AFL_DISABLE_LLVM_INSTRUMENTATION")) return;
  
    if (getenv(DEFER_ENV_VAR)) return;
  
    __afl_manual_init();
  
  }
  
  /* Initialization of the shmem - earliest possible because of LTO fixed mem. */
  
  __attribute__((constructor(CTOR_PRIO))) void __afl_auto_early(void) {
  
    is_persistent = !!getenv(PERSIST_ENV_VAR);
  
    if (getenv("AFL_DISABLE_LLVM_INSTRUMENTATION")) return;
  
    __afl_map_shm();
  
  }
  
  /* preset __afl_area_ptr #2 */
  
  __attribute__((constructor(1))) void __afl_auto_second(void) {
  
    if (getenv("AFL_DISABLE_LLVM_INSTRUMENTATION")) return;
    u8 *ptr;
  
    if (__afl_final_loc) {
  
      if (__afl_area_ptr && __afl_area_ptr != __afl_area_initial)
        free(__afl_area_ptr);
  
      if (__afl_map_addr)
        ptr = (u8 *)mmap((void *)__afl_map_addr, __afl_final_loc,
                         PROT_READ | PROT_WRITE,
                         MAP_FIXED_NOREPLACE | MAP_SHARED | MAP_ANONYMOUS, -1, 0);
      else
        ptr = (u8 *)malloc(__afl_final_loc);
  
      if (ptr && (ssize_t)ptr != -1) __afl_area_ptr = ptr;
  
    }
  
  }
  
  /* preset __afl_area_ptr #1 - at constructor level 0 global variables have
     not been set */
  
  __attribute__((constructor(0))) void __afl_auto_first(void) {
  
    if (getenv("AFL_DISABLE_LLVM_INSTRUMENTATION")) return;
    u8 *ptr;
  
    ptr = (u8 *)malloc(1024000);
  
    if (ptr && (ssize_t)ptr != -1) __afl_area_ptr = ptr;
  
  }
  
  /* The following stuff deals with supporting -fsanitize-coverage=trace-pc-guard.
     It remains non-operational in the traditional, plugin-backed LLVM mode.
     For more info about 'trace-pc-guard', see README.llvm.md.
  
     The first function (__sanitizer_cov_trace_pc_guard) is called back on every
     edge (as opposed to every basic block). */
  
  void __sanitizer_cov_trace_pc_guard(uint32_t *guard) {
  
    // For stability analysis, if you want to know to which function unstable
    // edge IDs belong - uncomment, recompile+install llvm_mode, recompile
    // the target. libunwind and libbacktrace are better solutions.
    // Set AFL_DEBUG_CHILD=1 and run afl-fuzz with 2>file to capture
    // the backtrace output
    /*
    uint32_t unstable[] = { ... unstable edge IDs };
    uint32_t idx;
    char bt[1024];
    for (idx = 0; i < sizeof(unstable)/sizeof(uint32_t); i++) {
  
      if (unstable[idx] == __afl_area_ptr[*guard]) {
  
        int bt_size = backtrace(bt, 256);
        if (bt_size > 0) {
  
          char **bt_syms = backtrace_symbols(bt, bt_size);
          if (bt_syms) {
  
            fprintf(stderr, "DEBUG: edge=%u caller=%s\n", unstable[idx],
    bt_syms[0]);
            free(bt_syms);
  
          }
  
        }
  
      }
  
    }
  
    */
  
  #if (LLVM_VERSION_MAJOR < 9)
  
    __afl_area_ptr[*guard]++;
  
  #else
  
    __afl_area_ptr[*guard] =
        __afl_area_ptr[*guard] + 1 + (__afl_area_ptr[*guard] == 255 ? 1 : 0);
  
  #endif
  
  }
  
  /* Init callback. Populates instrumentation IDs. Note that we're using
     ID of 0 as a special value to indicate non-instrumented bits. That may
     still touch the bitmap, but in a fairly harmless way. */
  
  void __sanitizer_cov_trace_pc_guard_init(uint32_t *start, uint32_t *stop) {
  
    u32   inst_ratio = 100;
    char *x;
  
    _is_sancov = 1;
  
    if (getenv("AFL_DEBUG")) {
  
      fprintf(stderr, "Running __sanitizer_cov_trace_pc_guard_init: %p-%p\n",
              start, stop);
  
    }
  
    if (start == stop || *start) return;
  
    x = getenv("AFL_INST_RATIO");
    if (x) inst_ratio = (u32)atoi(x);
  
    if (!inst_ratio || inst_ratio > 100) {
  
      fprintf(stderr, "[-] ERROR: Invalid AFL_INST_RATIO (must be 1-100).\n");
      abort();
  
    }
  
    /* Make sure that the first element in the range is always set - we use that
       to avoid duplicate calls (which can happen as an artifact of the underlying
       implementation in LLVM). */
  
    *(start++) = ++__afl_final_loc;
  
    while (start < stop) {
  
      if (R(100) < inst_ratio)
        *start = ++__afl_final_loc;
      else
        *start = 0;
  
      start++;
  
    }
  
  }
  
  ///// CmpLog instrumentation
  
  void __cmplog_ins_hook1(uint8_t arg1, uint8_t arg2) {
  
    if (unlikely(!__afl_cmp_map)) return;
  
    uintptr_t k = (uintptr_t)__builtin_return_address(0);
    k = (k >> 4) ^ (k << 8);
    k &= CMP_MAP_W - 1;
  
    __afl_cmp_map->headers[k].type = CMP_TYPE_INS;
  
    u32 hits = __afl_cmp_map->headers[k].hits;
    __afl_cmp_map->headers[k].hits = hits + 1;
    // if (!__afl_cmp_map->headers[k].cnt)
    //  __afl_cmp_map->headers[k].cnt = __afl_cmp_counter++;
  
    __afl_cmp_map->headers[k].shape = 0;
  
    hits &= CMP_MAP_H - 1;
    __afl_cmp_map->log[k][hits].v0 = arg1;
    __afl_cmp_map->log[k][hits].v1 = arg2;
  
  }
  
  void __cmplog_ins_hook2(uint16_t arg1, uint16_t arg2) {
  
    if (unlikely(!__afl_cmp_map)) return;
  
    uintptr_t k = (uintptr_t)__builtin_return_address(0);
    k = (k >> 4) ^ (k << 8);
    k &= CMP_MAP_W - 1;
  
    __afl_cmp_map->headers[k].type = CMP_TYPE_INS;
  
    u32 hits = __afl_cmp_map->headers[k].hits;
    __afl_cmp_map->headers[k].hits = hits + 1;
  
    __afl_cmp_map->headers[k].shape = 1;
  
    hits &= CMP_MAP_H - 1;
    __afl_cmp_map->log[k][hits].v0 = arg1;
    __afl_cmp_map->log[k][hits].v1 = arg2;
  
  }
  
  void __cmplog_ins_hook4(uint32_t arg1, uint32_t arg2) {
  
    if (unlikely(!__afl_cmp_map)) return;
  
    uintptr_t k = (uintptr_t)__builtin_return_address(0);
    k = (k >> 4) ^ (k << 8);
    k &= CMP_MAP_W - 1;
  
    __afl_cmp_map->headers[k].type = CMP_TYPE_INS;
  
    u32 hits = __afl_cmp_map->headers[k].hits;
    __afl_cmp_map->headers[k].hits = hits + 1;
  
    __afl_cmp_map->headers[k].shape = 3;
  
    hits &= CMP_MAP_H - 1;
    __afl_cmp_map->log[k][hits].v0 = arg1;
    __afl_cmp_map->log[k][hits].v1 = arg2;
  
  }
  
  void __cmplog_ins_hook8(uint64_t arg1, uint64_t arg2) {
  
    if (unlikely(!__afl_cmp_map)) return;
  
    uintptr_t k = (uintptr_t)__builtin_return_address(0);
    k = (k >> 4) ^ (k << 8);
    k &= CMP_MAP_W - 1;
  
    __afl_cmp_map->headers[k].type = CMP_TYPE_INS;
  
    u32 hits = __afl_cmp_map->headers[k].hits;
    __afl_cmp_map->headers[k].hits = hits + 1;
  
    __afl_cmp_map->headers[k].shape = 7;
  
    hits &= CMP_MAP_H - 1;
    __afl_cmp_map->log[k][hits].v0 = arg1;
    __afl_cmp_map->log[k][hits].v1 = arg2;
  
  }
  
  #if defined(__APPLE__)
    #pragma weak __sanitizer_cov_trace_const_cmp1 = __cmplog_ins_hook1
    #pragma weak __sanitizer_cov_trace_const_cmp2 = __cmplog_ins_hook2
    #pragma weak __sanitizer_cov_trace_const_cmp4 = __cmplog_ins_hook4
    #pragma weak __sanitizer_cov_trace_const_cmp8 = __cmplog_ins_hook8
  
    #pragma weak __sanitizer_cov_trace_cmp1 = __cmplog_ins_hook1
    #pragma weak __sanitizer_cov_trace_cmp2 = __cmplog_ins_hook2
    #pragma weak __sanitizer_cov_trace_cmp4 = __cmplog_ins_hook4
    #pragma weak __sanitizer_cov_trace_cmp8 = __cmplog_ins_hook8
  #else
  void __sanitizer_cov_trace_const_cmp1(uint8_t arg1, uint8_t arg2)
      __attribute__((alias("__cmplog_ins_hook1")));
  void __sanitizer_cov_trace_const_cmp2(uint16_t arg1, uint16_t arg2)
      __attribute__((alias("__cmplog_ins_hook2")));
  void __sanitizer_cov_trace_const_cmp4(uint32_t arg1, uint32_t arg2)
      __attribute__((alias("__cmplog_ins_hook4")));
  void __sanitizer_cov_trace_const_cmp8(uint64_t arg1, uint64_t arg2)
      __attribute__((alias("__cmplog_ins_hook8")));
  
  void __sanitizer_cov_trace_cmp1(uint8_t arg1, uint8_t arg2)
      __attribute__((alias("__cmplog_ins_hook1")));
  void __sanitizer_cov_trace_cmp2(uint16_t arg1, uint16_t arg2)
      __attribute__((alias("__cmplog_ins_hook2")));
  void __sanitizer_cov_trace_cmp4(uint32_t arg1, uint32_t arg2)
      __attribute__((alias("__cmplog_ins_hook4")));
  void __sanitizer_cov_trace_cmp8(uint64_t arg1, uint64_t arg2)
      __attribute__((alias("__cmplog_ins_hook8")));
  #endif                                                /* defined(__APPLE__) */
  
  void __sanitizer_cov_trace_switch(uint64_t val, uint64_t *cases) {
  
    if (unlikely(!__afl_cmp_map)) return;
  
    for (uint64_t i = 0; i < cases[0]; i++) {
  
      uintptr_t k = (uintptr_t)__builtin_return_address(0) + i;
      k = (k >> 4) ^ (k << 8);
      k &= CMP_MAP_W - 1;
  
      __afl_cmp_map->headers[k].type = CMP_TYPE_INS;
  
      u32 hits = __afl_cmp_map->headers[k].hits;
      __afl_cmp_map->headers[k].hits = hits + 1;
  
      __afl_cmp_map->headers[k].shape = 7;
  
      hits &= CMP_MAP_H - 1;
      __afl_cmp_map->log[k][hits].v0 = val;
      __afl_cmp_map->log[k][hits].v1 = cases[i + 2];
  
    }
  
  }
  
  // POSIX shenanigan to see if an area is mapped.
  // If it is mapped as X-only, we have a problem, so maybe we should add a check
  // to avoid to call it on .text addresses
  static int area_is_mapped(void *ptr, size_t len) {
  
    char *p = ptr;
    char *page = (char *)((uintptr_t)p & ~(sysconf(_SC_PAGE_SIZE) - 1));
  
    int r = msync(page, (p - page) + len, MS_ASYNC);
    if (r < 0) return errno != ENOMEM;
    return 1;
  
  }
  
  void __cmplog_rtn_hook(u8 *ptr1, u8 *ptr2) {
  
    if (unlikely(!__afl_cmp_map)) return;
  
    if (!area_is_mapped(ptr1, 32) || !area_is_mapped(ptr2, 32)) return;
  
    uintptr_t k = (uintptr_t)__builtin_return_address(0);
    k = (k >> 4) ^ (k << 8);
    k &= CMP_MAP_W - 1;
  
    __afl_cmp_map->headers[k].type = CMP_TYPE_RTN;
  
    u32 hits = __afl_cmp_map->headers[k].hits;
    __afl_cmp_map->headers[k].hits = hits + 1;
  
    __afl_cmp_map->headers[k].shape = 31;
  
    hits &= CMP_MAP_RTN_H - 1;
    __builtin_memcpy(((struct cmpfn_operands *)__afl_cmp_map->log[k])[hits].v0,
                     ptr1, 32);
    __builtin_memcpy(((struct cmpfn_operands *)__afl_cmp_map->log[k])[hits].v1,
                     ptr2, 32);
  
  }
  
  