Add klee-replay tool.

 - Not yet enabled as part of the build, and not recently tested.

 - This has also been trimmed down significantly from the version which is able
   to fail system calls, that functionality was too experimental to be generally
   useful.


git-svn-id: https://llvm.org/svn/llvm-project/klee/trunk@78148 91177308-0d34-0410-b5e6-96231b3b80d8

6 files changed, 943 insertions, 0 deletions

diff --git a/tools/klee-replay/Makefile b/tools/klee-replay/Makefile
new file mode 100644
index 00000000..fcce0483
--- /dev/null
+++ b/tools/klee-replay/Makefile
@@ -0,0 +1,19 @@
+#===-- tools/klee-replay/Makefile --------------------------*- Makefile -*--===#
+#
+#                     The KLEE Symbolic Virtual Machine
+#
+# This file is distributed under the University of Illinois Open Source
+# License. See LICENSE.TXT for details.
+#
+#===------------------------------------------------------------------------===#
+
+LEVEL=../..
+TOOLNAME = klee-replay
+
+USEDLIBS = kleeBasic.a
+LINK_COMPONENTS = 
+NO_PEDANTIC=1
+
+include $(LEVEL)/Makefile.common
+
+LIBS += -lutil
diff --git a/tools/klee-replay/fd_init.c b/tools/klee-replay/fd_init.c
new file mode 100644
index 00000000..e1dda970
--- /dev/null
+++ b/tools/klee-replay/fd_init.c
@@ -0,0 +1 @@
+#include "../../runtime/POSIX/fd_init.c"
diff --git a/tools/klee-replay/file-creator.c b/tools/klee-replay/file-creator.c
new file mode 100644
index 00000000..505fb8d7
--- /dev/null
+++ b/tools/klee-replay/file-creator.c
@@ -0,0 +1,532 @@
+//===-- file-creator.c ----------------------------------------------------===//
+//
+//                     The KLEE Symbolic Virtual Machine
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#include "klee-replay.h"
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include <errno.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <termios.h>
+#include <pty.h>
+#include <time.h>
+#include <sys/wait.h>
+#include <sys/time.h>
+#include <assert.h>
+
+static void create_file(int target_fd, 
+                       const char *target_name, 
+                       exe_disk_file_t *dfile,
+                       const char *tmpdir);
+static void check_file(int index, exe_disk_file_t *file);
+static void delete_file(const char *path, int recurse);
+
+
+#define __STDIN -1
+#define __STDOUT -2
+
+static int create_link(const char *fname, 
+                       exe_disk_file_t *dfile, 
+                       const char *tmpdir) {
+  char buf[64];
+  struct stat64 *s = dfile->stat;
+
+  // XXX Broken, we want this path to be somewhere else most likely.
+  sprintf(buf, "%s.lnk", fname);
+  s->st_mode = (s->st_mode & ~S_IFMT) | S_IFREG;
+  create_file(-1, buf, dfile, tmpdir);
+  
+  int res = symlink(buf, fname);
+  if (res < 0) {
+    perror("symlink");
+  }
+  
+  return open(fname, O_RDWR);
+}
+
+
+static int create_dir(const char *fname, exe_disk_file_t *dfile, 
+                      const char *tmpdir) {
+  int res = mkdir(fname, dfile->stat->st_mode);
+  if (res < 0) {
+    perror("mkdir");
+    return -1;
+  }
+  return open(fname, O_RDWR);
+}
+
+double getTime() {
+  struct timeval t;
+  gettimeofday(&t, NULL);
+  
+  return (double) t.tv_sec + ((double) t.tv_usec / 1000000.0);
+}
+
+/// Return true if program exited, false if timed out.
+int wait_for_timeout_or_exit(pid_t pid, const char *name, int *statusp) {
+  char *t = getenv("KLEE_REPLAY_TIMEOUT");
+  int timeout = t ? atoi(t) : 5;
+  double wait = timeout * .5;
+  double start = getTime();
+  fprintf(stderr, "note: %s: waiting %.2fs\n", name, wait);
+  while (getTime() - start < wait) {
+    struct timespec r = {0, 1000000};
+    nanosleep(&r, 0);
+    int res = waitpid(pid, statusp, WNOHANG);
+    if (res==pid)
+      return 1;
+  }
+  
+  return 0;
+}
+
+static int create_char_dev(const char *fname, exe_disk_file_t *dfile,
+                           const char *tmpdir) {
+  struct stat64 *s = dfile->stat;
+  unsigned flen = dfile->size;
+  char* contents = dfile->contents;
+
+  // Assume tty, kinda broken, need an actual device id or something
+  struct termios term, *ts=&term;
+  struct winsize win = { 24, 80, 0, 0 };
+  /* Just copied from my system, munged to match what fields
+     uclibc thinks are there. */
+  ts->c_iflag = 27906;
+  ts->c_oflag = 5;
+  ts->c_cflag = 1215;
+  ts->c_lflag = 35287;
+  ts->c_line = 0;
+  ts->c_cc[0] = '\x03';
+  ts->c_cc[1] = '\x1c';
+  ts->c_cc[2] = '\x7f';
+  ts->c_cc[3] = '\x15';
+  ts->c_cc[4] = '\x04';
+  ts->c_cc[5] = '\x00';
+  ts->c_cc[6] = '\x01';
+  ts->c_cc[7] = '\xff';
+  ts->c_cc[8] = '\x11';
+  ts->c_cc[9] = '\x13';
+  ts->c_cc[10] = '\x1a';
+  ts->c_cc[11] = '\xff';
+  ts->c_cc[12] = '\x12';
+  ts->c_cc[13] = '\x0f';
+  ts->c_cc[14] = '\x17';
+  ts->c_cc[15] = '\x16';
+  ts->c_cc[16] = '\xff';
+  ts->c_cc[17] = '\x0';
+  ts->c_cc[18] = '\x0';    
+  
+  {
+    char name[1024];
+    int amaster, aslave;
+    int res = openpty(&amaster, &aslave, name, &term, &win);
+    if (res < 0) {
+      perror("openpty");
+      exit(1);
+    }
+    
+    if (symlink(name, fname) == -1) {
+      fprintf(stderr, "unable to create sym link to tty\n");
+      perror("symlink");
+    }
+    
+    // pty will not be world writeable
+    s->st_mode &= ~02; 
+    
+    pid_t pid = fork();
+    if (pid < 0) {
+      perror("fork failed\n");
+      exit(1);
+    } else if (pid == 0) {
+      close(amaster);
+
+      fprintf(stderr, "note: pty slave: setting raw mode\n");
+      {
+        struct termio mode;
+        
+        int res = ioctl(aslave, TCGETA, &mode);
+        assert(!res);
+        mode.c_iflag = IGNBRK;
+        mode.c_oflag &= ~(OLCUC | ONLCR | OCRNL | ONLRET);
+        mode.c_lflag = 0;
+        mode.c_cc[VMIN] = 1;
+        mode.c_cc[VTIME] = 0;
+        res = ioctl(aslave, TCSETA, &mode);
+        assert(res == 0);
+      }
+
+      return aslave;
+    } else {
+      unsigned pos = 0;
+      int status;
+      fprintf(stderr, "note: pty master: starting\n");
+      close(aslave);
+      
+      while (pos < flen) {
+	int res = write(amaster, &contents[pos], flen - pos);
+	if (res<0) {
+	  if (errno != EINTR) {
+	    fprintf(stderr, "note: pty master: write error\n");
+	    perror("errno");
+	    break;
+	  }
+	} else if (res) {
+	  fprintf(stderr, "note: pty master: wrote: %d (of %d)\n", res, flen);
+	  pos += res;
+	}
+      }
+
+      if (wait_for_timeout_or_exit(pid, "pty master", &status))
+        goto pty_exit;
+      
+      fprintf(stderr, "note: pty master: closing & waiting\n");
+      close(amaster);
+      while (1) {
+	int res = waitpid(pid, &status, 0);
+	if (res < 0) {
+	  if (errno != EINTR)
+	    break;
+	} else {
+	  break;
+	}
+      }
+      
+    pty_exit:
+      close(amaster);
+      fprintf(stderr, "note: pty master: done\n");
+      process_status(status, 0, "PTY MASTER");
+    }
+  }
+}
+
+static int create_pipe(const char *fname, exe_disk_file_t *dfile,
+                       const char *tmpdir) {
+  //struct stat64 *s = dfile->stat;
+  unsigned flen = dfile->size;
+  char* contents = dfile->contents;
+
+  // XXX what is direction ? need more data
+  pid_t pid;
+  int fds[2];
+  int res = pipe(fds);
+  if (res < 0) {
+    perror("pipe");
+    exit(1);
+  }
+  
+  pid  = fork();
+  if (pid < 0) {
+    perror("fork");
+    exit(1);     
+  } else if (pid == 0) {
+    close(fds[1]);
+    return fds[0];
+  } else {
+    unsigned pos = 0;
+    int status;
+    fprintf(stderr, "note: pipe master: starting\n");
+    close(fds[0]);
+    
+    while (pos < flen) {
+      int res = write(fds[1], &contents[pos], flen - pos);
+      if (res<0) {
+	if (errno != EINTR)
+	  break;
+      } else if (res) {
+	pos += res;
+      }
+    }
+
+    if (wait_for_timeout_or_exit(pid, "pipe master", &status))
+      goto pipe_exit;
+    
+    fprintf(stderr, "note: pipe master: closing & waiting\n");
+    close(fds[1]);    
+    while (1) {
+      int res = waitpid(pid, &status, 0);
+      if (res < 0) {
+	if (errno != EINTR)
+	  break;
+      } else {
+	break;
+      }
+    }
+    
+  pipe_exit:
+    close(fds[1]);
+    fprintf(stderr, "note: pipe master: done\n");
+    process_status(status, 0, "PTY MASTER");
+  }
+}
+
+
+static int create_reg_file(const char *fname, exe_disk_file_t *dfile,
+                           const char *tmpdir) {    
+  struct stat64 *s = dfile->stat;
+  char* contents = dfile->contents;
+  unsigned flen = dfile->size;
+  unsigned mode = s->st_mode & 0777;
+
+  //fprintf(stderr, "Creating regular file\n");
+   
+  // Open in RDWR just in case we have to end up using this fd.
+
+  if (__exe_env.version == 0 && mode == 0)
+    mode = 0644;
+  
+  
+  int fd = open(fname, O_CREAT | O_RDWR, mode);
+  //    int fd = open(fname, O_CREAT | O_WRONLY, s->st_mode&0777);
+  if (fd < 0) {
+    fprintf(stderr, "Cannot create file %s\n", fname);
+    exit(1);
+  }
+  
+  int r = write(fd, contents, flen);
+  if (r < 0 || (unsigned) r != flen) {
+    fprintf(stderr, "Cannot write file %s\n", fname);
+    exit(1);
+  }
+  
+  struct timeval tv[2];
+  tv[0].tv_sec = s->st_atime;
+  tv[0].tv_usec = 0;
+  tv[1].tv_sec = s->st_mtime;
+  tv[1].tv_usec = 0;
+  futimes(fd, tv);
+  
+  // XXX: Now what we should do is reopen a new fd with the correct modes
+  // as they were given to the process.
+  lseek(fd, 0, SEEK_SET);
+  
+  return fd;
+}
+
+static int delete_dir(const char *path, int recurse) {
+  if (recurse) {
+    DIR *d = opendir(path);
+    struct dirent *de;
+
+    if (d) {
+      while ((de = readdir(d))) {
+        if (strcmp(de->d_name, ".")!=0 && strcmp(de->d_name, "..")!=0) {
+          char tmp[PATH_MAX];
+          sprintf(tmp, "%s/%s", path, de->d_name);
+          delete_file(tmp, 0);
+        }
+      }
+
+      closedir(d);
+    }
+  }
+ 
+  if (rmdir(path) == -1) {
+    fprintf(stderr, "Cannot create file %s (exists, is dir, can't remove)\n", path);
+    perror("rmdir");
+    return -1;
+  }
+
+  return 0;
+}
+
+static void delete_file(const char *path, int recurse) {
+  if (unlink(path) < 0 && errno != ENOENT) {
+    if (errno == EISDIR) {
+      delete_dir(path, 1);
+    } else {
+      fprintf(stderr, "Cannot create file %s (already exists)\n", path);
+      perror("unlink");
+    }
+  }
+}
+
+static void create_file(int target_fd,
+                        const char *target_name, 
+                        exe_disk_file_t *dfile,
+                        const char *tmpdir) {
+  struct stat64 *s = dfile->stat;
+  char tmpname[PATH_MAX];
+  const char *target;
+  int fd;
+
+  assert((target_fd == -1) ^ (target_name == NULL));
+
+  if (target_name) {
+    target = target_name;
+  } else {
+    sprintf(tmpname, "%s/fd%d", tmpdir, target_fd);
+    target = tmpname;
+  }
+
+  delete_file(target, 1);
+
+  // XXX get rid of me once a reasonable solution is found
+  s->st_uid = geteuid();
+  s->st_gid = getegid();
+
+  if (S_ISLNK(s->st_mode)) {
+    fd = create_link(target, dfile, tmpdir);
+  } 
+  else if (S_ISDIR(s->st_mode)) {
+    fd = create_dir(target, dfile, tmpdir);
+  } 
+  else if (S_ISCHR(s->st_mode)) {
+    fd = create_char_dev(target, dfile, tmpdir);
+  } 
+  else if (S_ISFIFO(s->st_mode) ||
+           (target_fd==0 && (s->st_mode & S_IFMT) == 0)) { // XXX hack
+    fd = create_pipe(target, dfile, tmpdir);
+  }
+  else {
+    fd = create_reg_file(target, dfile, tmpdir);
+  }
+
+  if (fd >= 0) {
+    if (target_fd != -1) {
+      close(target_fd);
+      if (dup2(fd, target_fd) < 0) {
+        fprintf(stderr, "note: dup2 failed for target: %d\n", target_fd);
+        perror("dup2");
+      }
+      close(fd);
+    } else {
+      // Only worry about 1 vs !1
+      if (s->st_nlink > 1) {
+        char tmp2[PATH_MAX];
+        sprintf(tmp2, "%s/%s.link2", tmpdir, target_name);
+        if (link(target_name, tmp2) < 0) {
+          perror("link");
+          exit(1);
+        }
+      }
+
+      close(fd);
+    }
+  }
+}
+
+void replay_create_files(exe_file_system_t *exe_fs) {
+  char tmpdir[PATH_MAX];
+  unsigned k;
+
+  if (!getcwd(tmpdir, PATH_MAX)) {
+    perror("getcwd");
+    exit(1);
+  }
+
+  strcat(tmpdir, ".temps");
+  delete_file(tmpdir, 1);
+  mkdir(tmpdir, 0755);  
+  
+  umask(0);
+  for (k=0; k < exe_fs->n_sym_files; k++) {
+    char name[2];
+    sprintf(name, "%c", 'A' + k);
+    create_file(-1, name, &exe_fs->sym_files[k], tmpdir);
+  }
+
+  if (exe_fs->sym_stdin)
+    create_file(0, NULL, exe_fs->sym_stdin, tmpdir);
+
+  if (exe_fs->sym_stdout)
+    create_file(1, NULL, exe_fs->sym_stdout, tmpdir);
+
+  if (exe_fs->sym_stdin)
+    check_file(__STDIN, exe_fs->sym_stdin);
+
+  if (exe_fs->sym_stdout)
+    check_file(__STDOUT, exe_fs->sym_stdout);
+  
+  for (k=0; k<exe_fs->n_sym_files; ++k)
+    check_file(k, &exe_fs->sym_files[k]);
+}
+
+static void check_file(int index, exe_disk_file_t *dfile) {
+  struct stat s;
+  int res;
+  char name[32];
+
+  switch (index) {
+  case __STDIN:
+    strcpy(name, "stdin"); 
+    res = fstat(0, &s);    
+    break;
+  case __STDOUT: 
+    strcpy(name, "stdout");
+    res = fstat(1, &s);
+    break;
+  default: 
+    name[0] = 'A' + index; 
+    name[1] = '\0'; 
+    res = stat(name, &s);
+    break;
+  }
+  
+  if (res < 0) {
+    fprintf(stderr, "warning: check_file %d: stat failure\n", index);
+    return;
+  }
+
+  if (s.st_dev != dfile->stat->st_dev) {
+    fprintf(stderr, "warning: check_file %s: dev mismatch: %d vs %d\n", 
+            name, (int) s.st_dev, (int) dfile->stat->st_dev);    
+  }
+/*   if (s.st_ino != dfile->stat->st_ino) { */
+/*     fprintf(stderr, "warning: check_file %s: ino mismatch: %d vs %d\n",  */
+/*             name, (int) s.st_ino, (int) dfile->stat->st_ino);     */
+/*   } */
+  if (s.st_mode != dfile->stat->st_mode) {
+    fprintf(stderr, "warning: check_file %s: mode mismatch: %#o vs %#o\n", 
+            name, s.st_mode, dfile->stat->st_mode);    
+  }
+  if (s.st_nlink != dfile->stat->st_nlink) {
+    fprintf(stderr, "warning: check_file %s: nlink mismatch: %d vs %d\n", 
+            name, (int) s.st_nlink, (int) dfile->stat->st_nlink);    
+  }
+  if (s.st_uid != dfile->stat->st_uid) {
+    fprintf(stderr, "warning: check_file %s: uid mismatch: %d vs %d\n", 
+            name, s.st_uid, dfile->stat->st_uid);    
+  }
+  if (s.st_gid != dfile->stat->st_gid) {
+    fprintf(stderr, "warning: check_file %s: gid mismatch: %d vs %d\n", 
+            name, s.st_gid, dfile->stat->st_gid);    
+  }
+  if (s.st_rdev != dfile->stat->st_rdev) {
+    fprintf(stderr, "warning: check_file %s: rdev mismatch: %d vs %d\n", 
+            name, (int) s.st_rdev, (int) dfile->stat->st_rdev);    
+  }
+  if (s.st_size != dfile->stat->st_size) {
+    fprintf(stderr, "warning: check_file %s: size mismatch: %d vs %d\n", 
+            name, (int) s.st_size, (int) dfile->stat->st_size);    
+  }
+  if (s.st_blksize != dfile->stat->st_blksize) {
+    fprintf(stderr, "warning: check_file %s: blksize mismatch: %d vs %d\n", 
+            name, (int) s.st_blksize, (int) dfile->stat->st_blksize);    
+  }
+  if (s.st_blocks != dfile->stat->st_blocks) {
+    fprintf(stderr, "warning: check_file %s: blocks mismatch: %d vs %d\n", 
+            name, (int) s.st_blocks, (int) dfile->stat->st_blocks);    
+  }
+/*   if (s.st_atime != dfile->stat->st_atime) { */
+/*     fprintf(stderr, "warning: check_file %s: atime mismatch: %d vs %d\n",  */
+/*             name, (int) s.st_atime, (int) dfile->stat->st_atime); */
+/*   } */
+/*   if (s.st_mtime != dfile->stat->st_mtime) { */
+/*     fprintf(stderr, "warning: check_file %s: mtime mismatch: %d vs %d\n",  */
+/*             name, (int) s.st_mtime, (int) dfile->stat->st_mtime);     */
+/*   } */
+/*   if (s.st_ctime != dfile->stat->st_ctime) { */
+/*     fprintf(stderr, "warning: check_file %s: ctime mismatch: %d vs %d\n",  */
+/*             name, (int) s.st_ctime, (int) dfile->stat->st_ctime);     */
+/*   } */
+}
diff --git a/tools/klee-replay/klee-replay.c b/tools/klee-replay/klee-replay.c
new file mode 100644
index 00000000..1163eaaa
--- /dev/null
+++ b/tools/klee-replay/klee-replay.c
@@ -0,0 +1,362 @@
+//===-- klee-replay.c -----------------------------------------------------===//
+//
+//                     The KLEE Symbolic Virtual Machine
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#include "klee-replay.h"
+
+#include "klee/Internal/ADT/KTest.h"
+
+#include <assert.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include <errno.h>
+#include <time.h>
+#include <unistd.h>
+#include <sys/signal.h>
+#include <sys/wait.h>
+
+static void __emit_error(const char *msg);
+
+static KTest* input = NULL;
+static unsigned obj_index = 0;
+
+static const char *progname = 0;
+static unsigned monitored_pid = 0;    
+static unsigned monitored_timeout;
+
+static void stop_monitored(int process) {
+  fprintf(stderr, "TIMEOUT: ATTEMPTING GDB EXIT\n");
+  int pid = fork();
+  if (pid < 0) {
+    fprintf(stderr, "ERROR: gdb_exit: fork failed\n");
+  } else if (pid == 0) {
+    /* Run gdb in a child process. */
+    const char *gdbargs[] = {
+      "/usr/bin/gdb",
+      "--pid", "",
+      "-q",
+      "--batch",
+      "--eval-command=call exit(1)",
+      0,
+      0
+    };
+    char pids[64];
+    sprintf(pids, "%d", process);
+
+    gdbargs[2] = pids;
+    /* Make sure gdb doesn't talk to the user */
+    close(0);
+
+    fprintf(stderr, "RUNNING GDB: ");
+    unsigned i;
+    for (i = 0; i != 5; ++i)
+      fprintf(stderr, "%s ", gdbargs[i]);
+    fprintf(stderr, "\n");
+
+    execvp(gdbargs[0], (char * const *) gdbargs);
+    perror("execvp");
+    _exit(66);
+  } else {
+    /* Parent process, wait for gdb to finish. */
+    int res, status;
+    do {
+      res = waitpid(pid, &status, 0);
+    } while (res < 0 && errno == EINTR);
+
+    if (res < 0) {
+      perror("waitpid");
+      _exit(66);
+    }
+  }
+}
+
+static void int_handler(int signal) {
+  fprintf(stderr, "%s: Received signal %d.  Killing monitored process(es)\n", 
+          progname, signal);
+  if (monitored_pid) {
+    stop_monitored(monitored_pid);
+    /* Kill the process group of monitored_pid.  Since we called
+       setpgrp() for pid, this will not kill us, or any of our
+       ancestors */
+    kill(-monitored_pid, SIGKILL);
+  } else {
+    _exit(99);
+  }
+}
+static void timeout_handler(int signal) {
+  fprintf(stderr, "EXIT STATUS: TIMED OUT (%d seconds)\n", monitored_timeout);
+  if (monitored_pid) {
+    stop_monitored(monitored_pid);
+    /* Kill the process group of monitored_pid.  Since we called
+       setpgrp() for pid, this will not kill us, or any of our
+       ancestors */
+    kill(-monitored_pid, SIGKILL);
+  } else {
+    _exit(88);
+  }
+}
+
+void process_status(int status,
+		    time_t elapsed, 
+		    const char *pfx) {
+
+  if (pfx)
+    fprintf(stderr, "%s: ", pfx);
+  if (WIFSIGNALED(status)) {
+    fprintf(stderr, "EXIT STATUS: CRASHED signal %d (%d seconds)\n",
+            WTERMSIG(status), (int) elapsed);
+    _exit(77);
+  } else if (WIFEXITED(status)) {
+    int rc = WEXITSTATUS(status);
+
+    char msg[64];
+    if (rc == 0) {
+      strcpy(msg, "NORMAL");
+    } else {
+      sprintf(msg, "ABNORMAL %d", rc);
+    }
+    fprintf(stderr, "EXIT STATUS: %s (%d seconds)\n", msg, (int) elapsed);
+    _exit(rc);
+  } else {
+    fprintf(stderr, "EXIT STATUS: NONE (%d seconds)\n", (int) elapsed);
+    _exit(0);
+  }
+}
+
+static void run_monitored(char *executable, int argc, char **argv) {
+  int pid;
+  const char *t = getenv("KLEE_REPLAY_TIMEOUT");  
+  if (!t)
+    t = "10000000";  
+  monitored_timeout = atoi(t);
+  
+  if (monitored_timeout==0) {
+    fprintf(stderr, "ERROR: invalid timeout (%s)\n", t);
+    _exit(1);
+  }
+
+  /* Kill monitored process(es) on SIGINT and SIGTERM */
+  signal(SIGINT, int_handler);
+  signal(SIGTERM, int_handler);
+  
+  signal(SIGALRM, timeout_handler);
+  pid = fork();
+  if (pid < 0) {
+    perror("fork");
+    _exit(66);
+  } else if (pid == 0) {
+    /* This process actually executes the target program.
+     *  
+     * Create a new process group for pid, and the process tree it may spawn. We
+     * do this, because later on we might want to kill pid _and_ all processes
+     * spawned by it and its descendants.
+     */
+    setpgrp();
+
+    execv(executable, argv);
+    perror("execv");
+    _exit(66);
+  } else {
+    /* Parent process which monitors the child. */
+    int res, status;
+    time_t start = time(0);
+    sigset_t masked;
+
+    sigemptyset(&masked);
+    sigaddset(&masked, SIGALRM);
+
+    monitored_pid = pid;
+    alarm(monitored_timeout);
+    do {
+      res = waitpid(pid, &status, 0);
+    } while (res < 0 && errno == EINTR);
+
+    if (res < 0) {
+      perror("waitpid");
+      _exit(66);
+    }
+    
+    /* Just in case, kill the process group of pid.  Since we called setpgrp()
+       for pid, this will not kill us, or any of our ancestors */
+    kill(-pid, SIGKILL);
+    process_status(status, time(0) - start, 0);
+  }
+}
+
+
+int main(int argc, char** argv) {
+  int prg_argc;
+  char ** prg_argv;  
+
+  progname = argv[0];
+
+  if (argc != 3) {
+    fprintf(stderr, "Usage: %s <executable> <ktest-file>\n",argv[0]);
+    fprintf(stderr, "       %s --create-files-only <ktest-file>\n", argv[0]);
+    fprintf(stderr, "       Set KLEE_REPLAY_TIMEOUT environment variable to set a timeout (in seconds)\n");
+    exit(1);
+  }
+
+  /* Special case hack for only creating files and not actually executing the
+   * program.
+   */
+  if (strcmp(argv[1], "--create-files-only") == 0) {
+    char* input_fname = argv[2];
+
+    input = kTest_fromFile(input_fname);
+    if (!input) {
+      fprintf(stderr, "%s: error: input file %s not valid.\n", progname,
+              input_fname);
+      exit(1);
+    }
+    
+    prg_argc = input->numArgs;
+    prg_argv = input->args;
+    prg_argv[0] = argv[1];
+    klee_init_env(&prg_argc, &prg_argv);
+    
+    replay_create_files(&__exe_fs);
+    return 0;
+  }
+
+  /* Normal execution path ... */
+
+  char* executable = argv[1];
+  char* input_fname = argv[2];
+  unsigned i;
+
+  FILE *f = fopen(executable, "r");
+  if (!f) {
+    fprintf(stderr, "Error: executable %s not found.\n", executable);
+    exit(1);
+  }
+  fclose(f);
+
+  input = kTest_fromFile(input_fname);
+  if (!input) {
+    fprintf(stderr, "%s: error: input file %s not valid.\n", progname, 
+            input_fname);
+    exit(1);
+  }
+  
+  prg_argc = input->numArgs;
+  prg_argv = input->args;
+  prg_argv[0] = argv[1];
+  klee_init_env(&prg_argc, &prg_argv);
+  fprintf(stderr, "ARGS: ");
+  for (i=0; i != (unsigned) prg_argc; ++i) {
+    char *s = prg_argv[i];
+    if (s[0]=='A' && s[1] && !s[2]) s[1] = '\0';
+    fprintf(stderr, "\"%s\" ", prg_argv[i]); 
+  }
+  fprintf(stderr, "\n");
+  
+  replay_create_files(&__exe_fs);
+
+  run_monitored(executable, prg_argc, prg_argv);
+
+  return 0;
+}
+
+
+/* Klee functions */
+
+int __fputc_unlocked(int c, FILE *f) {
+  return fputc_unlocked(c, f);
+}
+
+int __fgetc_unlocked(FILE *f) {
+  return fgetc_unlocked(f);
+}
+
+int klee_get_errno() {
+  return errno;
+}
+
+void klee_warning(char *name) {
+  fprintf(stderr, "WARNING: %s\n", name);
+}
+
+void klee_warning_once(char *name) {
+  fprintf(stderr, "WARNING: %s\n", name);
+}
+
+int klee_assume(int x) {
+  if (!x) {
+    fprintf(stderr, "WARNING: klee_assume(0)!\n");
+  }
+  return 0;
+}
+
+int klee_is_symbolic(int x) {
+  return 0;
+}
+
+void klee_prefer_cex(void *buffer, unsigned condition) {
+  ;
+}
+
+void klee_make_symbolic(void *addr, unsigned nbytes, const char *name) {
+  /* XXX remove model version code once new tests gen'd */
+  if (obj_index >= input->numObjects) {
+    if (strcmp("model_version", name) == 0) {
+      assert(nbytes == 4);
+      *((int*) addr) = 0;
+    } else {
+      __emit_error("ran out of appropriate inputs");
+    }
+  } else {
+    KTestObject *boo = &input->objects[obj_index];
+
+    if (strcmp("model_version", name) == 0 &&
+        strcmp("model_version", boo->name) != 0) {
+      assert(nbytes == 4);
+      *((int*) addr) = 0;
+    } else {
+      if (boo->numBytes != nbytes) {
+	fprintf(stderr, "make_symbolic mismatch, different sizes: "
+		"%d in input file, %d in code\n", boo->numBytes, nbytes);
+	exit(1);
+      } else {
+        memcpy(addr, boo->bytes, nbytes);
+        obj_index++;
+      }
+    }
+  }
+}
+
+/* Redefined here so that we can check the value read. */
+int klee_range(int min, int max, const char* name) {
+  int r;  
+  klee_make_symbolic(&r, sizeof r, name); 
+
+  if (r < min || r >= max) {
+    fprintf(stderr, "klee_range(%d, %d, %s) returned invalid result: %d\n", 
+	    min, max, name, r);
+    exit(1);
+  }  
+  return r;
+}
+
+void klee_report_error(const char *file, int line, 
+		       const char *message, const char *suffix) {
+  __emit_error(message);
+}
+
+void klee_mark_global(void *object) {
+  ;
+}
+
+/*** HELPER FUNCTIONS ***/
+
+static void __emit_error(const char *msg) {
+  fprintf(stderr, "ERROR: %s\n", msg);
+  exit(1);
+}
diff --git a/tools/klee-replay/klee-replay.h b/tools/klee-replay/klee-replay.h
new file mode 100644
index 00000000..668b5e3e
--- /dev/null
+++ b/tools/klee-replay/klee-replay.h
@@ -0,0 +1,28 @@
+//===-- klee-replay.h ------------------------------------------*- C++ -*--===//
+//
+//                     The KLEE Symbolic Virtual Machine
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef __KLEE_REPLAY_H__
+#define __KLEE_REPLAY_H__
+
+#define _LARGEFILE64_SOURCE
+#define _FILE_OFFSET_BITS 64
+
+// FIXME: This is a hack.
+#include "../../runtime/POSIX/fd.h"
+#include <sys/time.h>
+
+void replay_create_files(exe_file_system_t *exe_fs);
+
+void process_status(int status,
+		    time_t elapsed,
+		    const char *pfx)
+  __attribute__((noreturn));
+
+#endif
+
diff --git a/tools/klee-replay/klee_init_env.c b/tools/klee-replay/klee_init_env.c
new file mode 100644
index 00000000..229fe43d
--- /dev/null
+++ b/tools/klee-replay/klee_init_env.c
@@ -0,0 +1 @@
+#include "../../runtime/POSIX/klee_init_env.c"