[libFuzzer] Diff 27 - [AflDriver] Update afl driver to use std::istream::read() instead of posix read().

[zturner]

Same comment as before about c++ / c.

If we have to use C here, you could use fread(stdin...)

lib/Fuzzer/afl/afl_driver.cpp

 (the peak amount of virtual memory used in MB) and slowest_unit_time_secs. If
 the file does not exist it is created. If the file does exist then
 afl_driver assumes it was restarted by afl-fuzz and will try to read old
 statistics from the file. If that fails then the process will quit.
 
 */
 #include <assert.h>
 #include <chrono>
+#include <iostream>
 #include <stdio.h>
 #include <stdint.h>
 #include <stdlib.h>
 #include <string.h>
 #include <unistd.h>
 #include <errno.h>
 #include <signal.h>
 #include <sys/resource.h>
int main(int argc, char **argv) {
   __afl_manual_init();
 
   int N = 1000;
   if (argc >= 2)
     N = atoi(argv[1]);
   assert(N > 0);
   int num_runs = 0;
   while (__afl_persistent_loop(N)) {
-    ssize_t n_read = read(0, AflInputBuf, kMaxAflInputSize);
+    std::cin.read((char*) AflInputBuf, kMaxAflInputSize);
+    std::streamsize n_read = std::cin.gcount();
     if (n_read > 0) {
       // Copy AflInputBuf into a separate buffer to let asan find buffer
       // overflows. Don't use unique_ptr/etc to avoid extra dependencies.
       uint8_t *copy = new uint8_t[n_read];
       memcpy(copy, AflInputBuf, n_read);
 
       auto unit_start_time = std::chrono::system_clock::now();