X-Git-Url: http://mj.ucw.cz/gitweb/?a=blobdiff_plain;f=src%2Fbox.c;h=6c120f821f36436ddd478eb5f16fb6ac9d4be094;hb=62f031249f096887b62544f8e4513fd225ac86fd;hp=b76fd8a06037a8fc8fa34e3d8f9cb6b1cb40fb1c;hpb=666506e10535397d92733c7b6df0421c18708d04;p=moe.git

diff --git a/src/box.c b/src/box.c
index b76fd8a..6c120f8 100644
--- a/src/box.c
+++ b/src/box.c
@@ -1,7 +1,7 @@
 /*
- *	A Simple Testing Sandbox
+ *	A Simple Sandbox for MO-Eval
  *
- *	(c) 2001 Martin Mares <mj@ucw.cz>
+ *	(c) 2001--2008 Martin Mares <mj@ucw.cz>
  */
 
 #define _LARGEFILE64_SOURCE
@@ -27,21 +27,24 @@
 
 #define NONRET __attribute__((noreturn))
 #define UNUSED __attribute__((unused))
+#define ARRAY_SIZE(a) (int)(sizeof(a)/sizeof(a[0]))
 
 static int filter_syscalls;		/* 0=off, 1=liberal, 2=totalitarian */
-static int timeout;
+static int timeout;			/* milliseconds */
+static int wall_timeout;
 static int pass_environ;
-static int use_wall_clock;
 static int file_access;
 static int verbose;
 static int memory_limit;
 static char *redir_stdin, *redir_stdout;
+static char *set_cwd;
 
 static pid_t box_pid;
 static int is_ptraced;
 static volatile int timer_tick;
-static time_t start_time;
+static struct timeval start_time;
 static int ticks_per_sec;
+static int exec_seen;
 
 #if defined(__GLIBC__) && __GLIBC__ == 2 && __GLIBC_MINOR__ > 0
 /* glibc 2.1 or newer -> has lseek64 */
@@ -76,7 +79,7 @@ die(char *msg, ...)
 }
 
 static void __attribute__((format(printf,1,2)))
-log(char *msg, ...)
+msg(char *msg, ...)
 {
   va_list args;
   va_start(args, msg);
@@ -88,6 +91,254 @@ log(char *msg, ...)
   va_end(args);
 }
 
+static void *
+xmalloc(size_t size)
+{
+  void *p = malloc(size);
+  if (!p)
+    die("Out of memory");
+  return p;
+}
+
+static const char * const syscall_names[] = {
+#include "syscall-table.h"
+};
+#define NUM_SYSCALLS ARRAY_SIZE(syscall_names)
+#define NUM_ACTIONS (NUM_SYSCALLS+64)
+
+enum action {
+  A_DEFAULT,		// Use the default action
+  A_NO,		// Always forbid
+  A_YES,		// Always permit
+  A_FILENAME,		// Permit if arg1 is a known filename
+  A_LIBERAL = 128,	// Valid only in liberal mode
+};
+
+static unsigned char syscall_action[NUM_ACTIONS] = {
+#define S(x) [__NR_##x]
+
+    // Syscalls permitted for specific file names
+    S(open) = A_FILENAME,
+    S(creat) = A_FILENAME,
+    S(unlink) = A_FILENAME,
+    S(oldstat) = A_FILENAME,
+    S(access) = A_FILENAME,			
+    S(oldlstat) = A_FILENAME,			
+    S(truncate) = A_FILENAME,
+    S(stat) = A_FILENAME,
+    S(lstat) = A_FILENAME,
+    S(truncate64) = A_FILENAME,
+    S(stat64) = A_FILENAME,
+    S(lstat64) = A_FILENAME,
+    S(readlink) = A_FILENAME,
+
+    // Syscalls permitted always
+    S(exit) = A_YES,
+    S(read) = A_YES,
+    S(write) = A_YES,
+    S(close) = A_YES,
+    S(lseek) = A_YES,
+    S(getpid) = A_YES,
+    S(getuid) = A_YES,
+    S(oldfstat) = A_YES,
+    S(dup) = A_YES,
+    S(brk) = A_YES,
+    S(getgid) = A_YES,
+    S(geteuid) = A_YES,
+    S(getegid) = A_YES,
+    S(dup2) = A_YES,
+    S(ftruncate) = A_YES,
+    S(fstat) = A_YES,
+    S(personality) = A_YES,
+    S(_llseek) = A_YES,
+    S(readv) = A_YES,
+    S(writev) = A_YES,
+    S(getresuid) = A_YES,
+#ifdef __NR_pread64
+    S(pread64) = A_YES,
+    S(pwrite64) = A_YES,
+#else
+    S(pread) = A_YES,
+    S(pwrite) = A_YES,
+#endif
+    S(ftruncate64) = A_YES,
+    S(fstat64) = A_YES,
+    S(fcntl) = A_YES,
+    S(fcntl64) = A_YES,
+    S(mmap) = A_YES,
+    S(munmap) = A_YES,
+    S(ioctl) = A_YES,
+    S(uname) = A_YES,
+    S(gettid) = A_YES,
+    S(set_thread_area) = A_YES,
+    S(get_thread_area) = A_YES,
+    S(exit_group) = A_YES,
+
+    // Syscalls permitted only in liberal mode
+    S(time) = A_YES | A_LIBERAL,
+    S(alarm) = A_YES | A_LIBERAL,
+    S(pause) = A_YES | A_LIBERAL,
+    S(signal) = A_YES | A_LIBERAL,
+    S(fchmod) = A_YES | A_LIBERAL,
+    S(sigaction) = A_YES | A_LIBERAL,
+    S(sgetmask) = A_YES | A_LIBERAL,
+    S(ssetmask) = A_YES | A_LIBERAL,
+    S(sigsuspend) = A_YES | A_LIBERAL,
+    S(sigpending) = A_YES | A_LIBERAL,
+    S(getrlimit) = A_YES | A_LIBERAL,
+    S(getrusage) = A_YES | A_LIBERAL,
+    S(ugetrlimit) = A_YES | A_LIBERAL,
+    S(gettimeofday) = A_YES | A_LIBERAL,
+    S(select) = A_YES | A_LIBERAL,
+    S(readdir) = A_YES | A_LIBERAL,
+    S(setitimer) = A_YES | A_LIBERAL,
+    S(getitimer) = A_YES | A_LIBERAL,
+    S(sigreturn) = A_YES | A_LIBERAL,
+    S(mprotect) = A_YES | A_LIBERAL,
+    S(sigprocmask) = A_YES | A_LIBERAL,
+    S(getdents) = A_YES | A_LIBERAL,
+    S(getdents64) = A_YES | A_LIBERAL,
+    S(_newselect) = A_YES | A_LIBERAL,
+    S(fdatasync) = A_YES | A_LIBERAL,
+    S(mremap) = A_YES | A_LIBERAL,
+    S(poll) = A_YES | A_LIBERAL,
+    S(getcwd) = A_YES | A_LIBERAL,
+    S(nanosleep) = A_YES | A_LIBERAL,
+    S(rt_sigreturn) = A_YES | A_LIBERAL,
+    S(rt_sigaction) = A_YES | A_LIBERAL,
+    S(rt_sigprocmask) = A_YES | A_LIBERAL,
+    S(rt_sigpending) = A_YES | A_LIBERAL,
+    S(rt_sigtimedwait) = A_YES | A_LIBERAL,
+    S(rt_sigqueueinfo) = A_YES | A_LIBERAL,
+    S(rt_sigsuspend) = A_YES | A_LIBERAL,
+    S(mmap2) = A_YES | A_LIBERAL,
+    S(_sysctl) = A_YES | A_LIBERAL,
+#undef S
+};
+
+static const char *
+syscall_name(unsigned int id, char *buf)
+{
+  if (id < NUM_SYSCALLS && syscall_names[id])
+    return syscall_names[id];
+  else
+    {
+      sprintf(buf, "#%d", id);
+      return buf;
+    }
+}
+
+static int
+syscall_by_name(char *name)
+{
+  for (unsigned int i=0; i<NUM_SYSCALLS; i++)
+    if (syscall_names[i] && !strcmp(syscall_names[i], name))
+      return i;
+  if (name[0] == '#')
+    name++;
+  if (!*name)
+    return -1;
+  char *ep;
+  unsigned long l = strtoul(name, &ep, 0);
+  if (*ep)
+    return -1;
+  if (l >= NUM_ACTIONS)
+    return NUM_ACTIONS;
+  return l;
+}
+
+static int
+set_syscall_action(char *a)
+{
+  char *sep = strchr(a, '=');
+  enum action act = A_YES;
+  if (sep)
+    {
+      *sep++ = 0;
+      if (!strcmp(sep, "yes"))
+	act = A_YES;
+      else if (!strcmp(sep, "no"))
+	act = A_NO;
+      else if (!strcmp(sep, "file"))
+	act = A_FILENAME;
+      else
+	return 0;
+    }
+
+  int sys = syscall_by_name(a);
+  if (sys < 0)
+    die("Unknown syscall `%s'", a);
+  if (sys >= NUM_ACTIONS)
+    die("Syscall `%s' out of range", a);
+  syscall_action[sys] = act;
+  return 1;
+}
+
+struct path_rule {
+  char *path;
+  enum action action;
+  struct path_rule *next;
+};
+
+static struct path_rule default_path_rules[] = {
+  { "/etc/", A_YES },
+  { "/lib/", A_YES },
+  { "/usr/lib/", A_YES },
+  { "/opt/lib/", A_YES },
+  { "/usr/share/zoneinfo/", A_YES },
+  { "/usr/share/locale/", A_YES },
+  { "/dev/null", A_YES },
+  { "/dev/zero", A_YES },
+  { "/proc/meminfo", A_YES },
+  { "/proc/self/stat", A_YES },
+  { "/proc/self/exe", A_YES },			// Needed by FPC 2.0.x runtime
+};
+
+static struct path_rule *user_path_rules;
+static struct path_rule **last_path_rule = &user_path_rules;
+
+static int
+set_path_action(char *a)
+{
+  char *sep = strchr(a, '=');
+  enum action act = A_YES;
+  if (sep)
+    {
+      *sep++ = 0;
+      if (!strcmp(sep, "yes"))
+	act = A_YES;
+      else if (!strcmp(sep, "no"))
+	act = A_NO;
+      else
+	return 0;
+    }
+
+  struct path_rule *r = xmalloc(sizeof(*r) + strlen(a));
+  r->path = (char *)(r+1);
+  strcpy(r->path, a);
+  r->action = act;
+  r->next = NULL;
+  *last_path_rule = r;
+  last_path_rule = &r->next;
+  return 1;
+}
+
+static enum action
+match_path_rule(struct path_rule *r, char *path)
+{
+  char *rr = r->path;
+  while (*rr)
+    if (*rr++ != *path++)
+      {
+	if (rr[-1] == '/' && !path[-1])
+	  break;
+	return A_DEFAULT;
+      }
+  if (rr > r->path && rr[-1] != '/' && *path)
+    return A_DEFAULT;
+  return r->action;
+}
+
 static void
 valid_filename(unsigned long addr)
 {
@@ -95,7 +346,7 @@ valid_filename(unsigned long addr)
   static int mem_fd;
 
   if (!file_access)
-    die("File access forbidden.");
+    die("File access forbidden");
   if (file_access >= 9)
     return;
 
@@ -116,130 +367,81 @@ valid_filename(unsigned long addr)
 	  if (l > remains)
 	    l = remains;
 	  if (!l)
-	    die("Access to file with name too long.");
+	    die("Access to file with name too long");
 	  if (long_seek(mem_fd, addr, SEEK_SET) < 0)
 	    die("long_seek(mem): %m");
 	  remains = read(mem_fd, end, l);
 	  if (remains < 0)
 	    die("read(mem): %m");
 	  if (!remains)
-	    die("Access to file with name out of memory.");
+	    die("Access to file with name out of memory");
 	  end += l;
 	  addr += l;
 	}
     }
   while (*p++);
 
-  log("[%s] ", namebuf);
+  msg("[%s] ", namebuf);
   if (file_access >= 3)
     return;
+
+  // Everything in current directory is permitted
   if (!strchr(namebuf, '/') && strcmp(namebuf, ".."))
     return;
+
+  // ".." anywhere in the path is forbidden
+  enum action act = A_DEFAULT;
+  if (strstr(namebuf, ".."))
+    act = A_NO;
+
+  // Scan user rules
+  for (struct path_rule *r = user_path_rules; r && !act; r=r->next)
+    act = match_path_rule(r, namebuf);
+
+  // Scan built-in rules
   if (file_access >= 2)
-    {
-      if ((!strncmp(namebuf, "/etc/", 5) ||
-	   !strncmp(namebuf, "/lib/", 5) ||
-	   !strncmp(namebuf, "/usr/lib/", 9))
-	  && !strstr(namebuf, ".."))
-	return;
-      if (!strcmp(namebuf, "/dev/null") ||
-	  !strcmp(namebuf, "/dev/zero"))
-	return;
-    }
-  die("Forbidden access to file `%s'.", namebuf);
+    for (int i=0; i<ARRAY_SIZE(default_path_rules) && !act; i++)
+      act = match_path_rule(&default_path_rules[i], namebuf);
+
+  if (act != A_YES)
+    die("Forbidden access to file `%s'", namebuf);
 }
 
 static int
 valid_syscall(struct user *u)
 {
-  switch (u->regs.orig_eax)
+  unsigned int sys = u->regs.orig_eax;
+  enum action act = (sys < NUM_ACTIONS) ? syscall_action[sys] : A_DEFAULT;
+
+  if (act & A_LIBERAL)
     {
-    case SYS_execve:
-      {
-	static int exec_counter;
-	return !exec_counter++;
-      }
-    case SYS_open:
-    case SYS_creat:
-    case SYS_unlink:
-    case SYS_oldstat:
-    case SYS_access:			
-    case SYS_oldlstat:			
-    case SYS_truncate:
-    case SYS_stat:
-    case SYS_lstat:
-    case SYS_truncate64:
-    case SYS_stat64:
-    case SYS_lstat64:
-      valid_filename(u->regs.ebx);
+      if (filter_syscalls == 1)
+        act &= ~A_LIBERAL;
+      else
+        act = A_DEFAULT;
+    }
+  switch (act)
+    {
+    case A_YES:
       return 1;
-    case SYS_exit:
-    case SYS_read:
-    case SYS_write:
-    case SYS_close:
-    case SYS_lseek:
-    case SYS_getpid:
-    case SYS_getuid:
-    case SYS_oldfstat:
-    case SYS_dup:
-    case SYS_brk:
-    case SYS_getgid:
-    case SYS_geteuid:
-    case SYS_getegid:
-    case SYS_dup2:
-    case SYS_ftruncate:
-    case SYS_fstat:
-    case SYS_personality:
-    case SYS__llseek:
-    case SYS_readv:
-    case SYS_writev:
-    case SYS_getresuid:
-    case SYS_pread:
-    case SYS_pwrite:
-    case SYS_ftruncate64:
-    case SYS_fstat64:
-    case SYS_fcntl:
-    case SYS_mmap:
-    case SYS_munmap:
-    case SYS_ioctl:
-    case SYS_uname:
+    case A_NO:
+      return 0;
+    case A_FILENAME:
+      valid_filename(u->regs.ebx);
       return 1;
-    case SYS_time:
-    case SYS_alarm:
-    case SYS_pause:
-    case SYS_signal:
-    case SYS_fchmod:
-    case SYS_sigaction:
-    case SYS_sgetmask:
-    case SYS_ssetmask:
-    case SYS_sigsuspend:
-    case SYS_sigpending:
-    case SYS_getrlimit:
-    case SYS_getrusage:
-    case SYS_gettimeofday:
-    case SYS_select:
-    case SYS_readdir:
-    case SYS_setitimer:
-    case SYS_getitimer:
-    case SYS_sigreturn:
-    case SYS_mprotect:
-    case SYS_sigprocmask:
-    case SYS_getdents:
-    case SYS__newselect:
-    case SYS_fdatasync:
-    case SYS_mremap:
-    case SYS_poll:
-    case SYS_getcwd:
-    case SYS_nanosleep:
-    case SYS_rt_sigreturn:
-    case SYS_rt_sigaction:
-    case SYS_rt_sigprocmask:
-    case SYS_rt_sigpending:
-    case SYS_rt_sigtimedwait:
-    case SYS_rt_sigqueueinfo:
-    case SYS_rt_sigsuspend:
-    case SYS_mmap2:
-      return (filter_syscalls == 1);
+    default: ;
+    }
+
+  switch (sys)
+    {
+    case __NR_kill:
+      if (u->regs.ebx == box_pid)
+	die("Committed suicide by signal %d", (int)u->regs.ecx);
+      return 0;
+    case __NR_tgkill:
+      if (u->regs.ebx == box_pid && u->regs.ecx == box_pid)
+	die("Committed suicide by signal %d", (int)u->regs.edx);
+      return 0;
     default:
       return 0;
     }
@@ -257,20 +459,28 @@ static void
 signal_int(int unused UNUSED)
 {
   /* Interrupts are fatal, so no synchronization requirements. */
-  die("Interrupted.");
+  die("Interrupted");
 }
 
 static void
 check_timeout(void)
 {
-  int sec;
-
-  if (use_wall_clock)
-    sec = time(NULL) - start_time;
-  else
+  if (wall_timeout)
+    {
+      struct timeval now, wall;
+      int wall_ms;
+      gettimeofday(&now, NULL);
+      timersub(&now, &start_time, &wall);
+      wall_ms = wall.tv_sec*1000 + wall.tv_usec/1000;
+      if (wall_ms > wall_timeout)
+        die("Time limit exceeded (wall clock)");
+      if (verbose > 1)
+        fprintf(stderr, "[wall time check: %d msec]\n", wall_ms);
+    }
+  if (timeout)
     {
       char buf[4096], *x;
-      int c, utime, stime;
+      int c, utime, stime, ms;
       static int proc_status_fd;
       if (!proc_status_fd)
 	{
@@ -298,12 +508,12 @@ check_timeout(void)
 	x++;
       if (sscanf(x, "%*c %*d %*d %*d %*d %*d %*d %*d %*d %*d %*d %d %d", &utime, &stime) != 2)
 	die("proc syntax error 2");
-      sec = (utime + stime)/ticks_per_sec;
+      ms = (utime + stime) * 1000 / ticks_per_sec;
+      if (verbose > 1)
+	fprintf(stderr, "[time check: %d msec]\n", ms);
+      if (ms > timeout)
+	die("Time limit exceeded");
     }
-  if (verbose > 1)
-    fprintf(stderr, "[timecheck: %d seconds]\n", sec);
-  if (sec > timeout)
-    die("Time limit exceeded.");
 }
 
 static void
@@ -316,11 +526,11 @@ boxkeeper(void)
   bzero(&sa, sizeof(sa));
   sa.sa_handler = signal_int;
   sigaction(SIGINT, &sa, NULL);
-  start_time = time(NULL);
+  gettimeofday(&start_time, NULL);
   ticks_per_sec = sysconf(_SC_CLK_TCK);
   if (ticks_per_sec <= 0)
     die("Invalid ticks_per_sec!");
-  if (timeout)
+  if (timeout || wall_timeout)
     {
       sa.sa_handler = signal_alarm;
       sigaction(SIGALRM, &sa, NULL);
@@ -347,22 +557,30 @@ boxkeeper(void)
 	die("wait4: unknown pid %d exited!", p);
       if (WIFEXITED(stat))
 	{
-	  struct timeval total;
-	  int wall;
+	  struct timeval total, now, wall;
+	  int total_ms, wall_ms;
 	  box_pid = 0;
 	  if (WEXITSTATUS(stat))
-	    die("Exited with error status %d.", WEXITSTATUS(stat));
+	    die("Exited with error status %d", WEXITSTATUS(stat));
 	  timeradd(&rus.ru_utime, &rus.ru_stime, &total);
-	  wall = time(NULL) - start_time;
-	  if ((use_wall_clock ? wall : total.tv_sec) > timeout)
-	    die("Timeout exceeded (after exit).");
-	  fprintf(stderr, "OK (%d sec real, %d sec wall, %d syscalls)\n", (int) total.tv_sec, wall, syscall_count);
+	  total_ms = total.tv_sec*1000 + total.tv_usec/1000;
+	  gettimeofday(&now, NULL);
+	  timersub(&now, &start_time, &wall);
+	  wall_ms = wall.tv_sec*1000 + wall.tv_usec/1000;
+	  if (timeout && total_ms > timeout)
+	    die("Time limit exceeded");
+	  if (wall_timeout && wall_ms > wall_timeout)
+	    die("Time limit exceeded (wall clock)");
+	  fprintf(stderr, "OK (%d.%03d sec real, %d.%03d sec wall, %d syscalls)\n",
+	      (int) total.tv_sec, (int) total.tv_usec/1000,
+	      (int) wall.tv_sec, (int) wall.tv_usec/1000,
+	      syscall_count);
 	  exit(0);
 	}
       if (WIFSIGNALED(stat))
 	{
 	  box_pid = 0;
-	  die("Caught fatal signal %d.", WTERMSIG(stat));
+	  die("Caught fatal signal %d%s", WTERMSIG(stat), (syscall_count ? "" : " during startup"));
 	}
       if (WIFSTOPPED(stat))
 	{
@@ -375,12 +593,20 @@ boxkeeper(void)
 		die("ptrace(PTRACE_GETREGS): %m");
 	      stop_count++;
 	      if (!stop_count)			/* Traceme request */
-		log(">> Traceme request caught\n");
+		msg(">> Traceme request caught\n");
 	      else if (stop_count & 1)		/* Syscall entry */
 		{
-		  log(">> Syscall %3ld (%08lx,%08lx,%08lx) ", u.regs.orig_eax, u.regs.ebx, u.regs.ecx, u.regs.edx);
-		  syscall_count++;
-		  if (!valid_syscall(&u))
+		  char namebuf[32];
+		  msg(">> Syscall %-12s (%08lx,%08lx,%08lx) ", syscall_name(u.regs.orig_eax, namebuf), u.regs.ebx, u.regs.ecx, u.regs.edx);
+		  if (!exec_seen)
+		    {
+		      msg("[master] ");
+		      if (u.regs.orig_eax == __NR_execve)
+			exec_seen = 1;
+		    }
+		  else if (valid_syscall(&u))
+		    syscall_count++;
+		  else
 		    {
 		      /*
 		       * Unfortunately, PTRACE_KILL kills _after_ the syscall completes,
@@ -391,20 +617,20 @@ boxkeeper(void)
 		      u.regs.orig_eax = 0xffffffff;
 		      if (ptrace(PTRACE_SETREGS, box_pid, NULL, &u) < 0)
 			die("ptrace(PTRACE_SETREGS): %m");
-		      die("Forbidden syscall %d.", sys);
+		      die("Forbidden syscall %s", syscall_name(sys, namebuf));
 		    }
 		}
 	      else					/* Syscall return */
-		log("= %ld\n", u.regs.eax);
+		msg("= %ld\n", u.regs.eax);
 	      ptrace(PTRACE_SYSCALL, box_pid, 0, 0);
 	    }
 	  else if (sig != SIGSTOP && sig != SIGXCPU && sig != SIGXFSZ)
 	    {
-	      log(">> Signal %d\n", sig);
+	      msg(">> Signal %d\n", sig);
 	      ptrace(PTRACE_SYSCALL, box_pid, 0, sig);
 	    }
 	  else
-	    die("Received signal %d.", sig);
+	    die("Received signal %d", sig);
 	}
       else
 	die("wait4: unknown status %x, giving up!", stat);
@@ -416,10 +642,12 @@ box_inside(int argc, char **argv)
 {
   struct rlimit rl;
   char *args[argc+1];
-  char *env[1] = { NULL };
+  char *env[] = { "LIBC_FATAL_STDERR_=1", NULL };
 
   memcpy(args, argv, argc * sizeof(char *));
   args[argc] = NULL;
+  if (set_cwd && chdir(set_cwd))
+    die("chdir: %m");
   if (redir_stdin)
     {
       close(0);
@@ -432,8 +660,7 @@ box_inside(int argc, char **argv)
       if (open(redir_stdout, O_WRONLY | O_CREAT | O_TRUNC, 0666) != 1)
 	die("open(\"%s\"): %m", redir_stdout);
     }
-  close(2);
-  dup(1);
+  dup2(1, 2);
   setpgrp();
   if (memory_limit)
     {
@@ -444,8 +671,14 @@ box_inside(int argc, char **argv)
   rl.rlim_cur = rl.rlim_max = 64;
   if (setrlimit(RLIMIT_NOFILE, &rl) < 0)
     die("setrlimit: %m");
-  if (filter_syscalls && ptrace(PTRACE_TRACEME) < 0)
-    die("ptrace(PTRACE_TRACEME): %m");
+  if (filter_syscalls)
+    {
+      if (ptrace(PTRACE_TRACEME) < 0)
+	die("ptrace(PTRACE_TRACEME): %m");
+      /* Trick: Make sure that we are stopped until the boxkeeper wakes up. */
+      signal(SIGCHLD, SIG_IGN);
+      raise(SIGCHLD);
+    }
   execve(args[0], args, (pass_environ ? environ : env));
   die("execve(\"%s\"): %m", args[0]);
 }
@@ -465,9 +698,14 @@ Options:\n\
 -i <file>\tRedirect stdin from <file>\n\
 -m <size>\tLimit address space to <size> KB\n\
 -o <file>\tRedirect stdout to <file>\n\
--t <time>\tStop after <time> seconds\n\
+-p <path>\tPermit access to the specified path (or subtree if it ends with a `/')\n\
+-p <path>=<act>\tDefine action for the specified path (<act>=yes/no)\n\
+-s <sys>\tPermit the specified syscall (be careful)\n\
+-s <sys>=<act>\tDefine action for the specified syscall (<act>=yes/no/file)\n\
+-t <time>\tSet run time limit (seconds, fractions allowed)\n\
+-T\t\tAllow syscalls for measuring run time\n\
 -v\t\tBe verbose\n\
--w\t\tMeasure wall clock time instead of run time\n\
+-w <time>\tSet wall clock time limit (seconds, fractions allowed)\n\
 ");
   exit(1);
 }
@@ -477,16 +715,15 @@ main(int argc, char **argv)
 {
   int c;
   uid_t uid;
-  char *cwd = NULL;
 
-  while ((c = getopt(argc, argv, "a:c:efi:m:o:t:vw")) >= 0)
+  while ((c = getopt(argc, argv, "a:c:efi:m:o:p:s:t:Tvw:")) >= 0)
     switch (c)
       {
       case 'a':
 	file_access = atol(optarg);
 	break;
       case 'c':
-	cwd = optarg;
+	set_cwd = optarg;
 	break;
       case 'e':
 	pass_environ = 1;
@@ -503,14 +740,25 @@ main(int argc, char **argv)
       case 'o':
 	redir_stdout = optarg;
 	break;
+      case 'p':
+	if (!set_path_action(optarg))
+	  usage();
+	break;
+      case 's':
+	if (!set_syscall_action(optarg))
+	  usage();
+	break;
       case 't':
-	timeout = atol(optarg);
+	timeout = 1000*atof(optarg);
+	break;
+      case 'T':
+	syscall_action[__NR_times] = A_YES;
 	break;
       case 'v':
 	verbose++;
 	break;
       case 'w':
-	use_wall_clock = 1;
+        wall_timeout = 1000*atof(optarg);
 	break;
       default:
 	usage();
@@ -521,8 +769,6 @@ main(int argc, char **argv)
   uid = geteuid();
   if (setreuid(uid, uid) < 0)
     die("setreuid: %m");
-  if (cwd && chdir(cwd))
-    die("chdir: %m");
   box_pid = fork();
   if (box_pid < 0)
     die("fork: %m");