Revert of Non-SFI mode: Add Linux asynchronous signal support

src/untrusted/irt/irt.h

Index: src/untrusted/irt/irt.h
diff --git a/src/untrusted/irt/irt.h b/src/untrusted/irt/irt.h
index 4afde79d95c4d6cece433504fbcbc315fce448c5..ad59ee2a46c366dcdb00de17e992da53c3cf73ad 100644
--- a/src/untrusted/irt/irt.h
+++ b/src/untrusted/irt/irt.h
@@ -20,8 +20,6 @@
 
 typedef int64_t nacl_irt_off_t;
 typedef uint32_t nacl_irt_clockid_t;
-typedef uintptr_t nacl_irt_tid_t;
-#define NACL_IRT_MAIN_THREAD_TID 0
 
 /*
  * Under newlib, the 'struct stat' defined in <sys/stat.h> matches the
@@ -255,23 +253,6 @@
 };
 
 /*
- * This interface is only available on Non-SFI Mode.
- */
-#define NACL_IRT_THREAD_v0_2   "nacl-irt-thread-0.2"
-struct nacl_irt_thread_v0_2 {
-  /*
-   * This interface is the same as nacl_irt_thread_v0_1, with the additional
-   * feature that it assigns the thread ID of the child thread into
-   * |child_tid| before the child thread starts and before execution control
-   * returns to the parent.
-   */
-  int (*thread_create)(void (*start_func)(void), void *stack, void *thread_ptr,
-                       nacl_irt_tid_t *child_tid);
-  void (*thread_exit)(int32_t *stack_flag);
-  int (*thread_nice)(const int nice);
-};
-
-/*
  * The irt_futex interface is based on Linux's futex() system call.
  *
  * irt_futex provides process-private futexes, so futex wait queues are
@@ -467,59 +448,6 @@
   int (*clear_cache)(void *addr, size_t size);
 };
 
-/*
- * This interface is only available on Non-SFI Mode.
- *
- * For more information, consult documentation/nonsfi_mode_async_signals.txt.
- */
-
-typedef void (*NaClIrtAsyncSignalHandler)(
-    struct NaClExceptionContext *context);
-
-#define NACL_IRT_ASYNC_SIGNAL_HANDLING_v0_1 "nacl-irt-async-signal-handling-0.1"
-struct nacl_irt_async_signal_handling {
-  /*
-   * NaCl applications can register a single, global async signal handler that
-   * will be invoked on the thread that receives the signal.  When
-   * send_async_signal is called, |handler| is invoked on the thread specified
-   * by |tid| on the thread's stack and without modifying the underlying signal
-   * mask (as opposed to the POSIX behavior), so it is possible for |handler| to
-   * be invoked recursively (if a signal is sent from |handler|) and
-   * concurrently (if two threads send signals at the same time).
-   *
-   * If the thread was executing an IRT function, the suspended thread will
-   * continue it after |handler| finishes.  In other words, no IRT function will
-   * be aborted.
-   *
-   * You can safely use only async-signal-safe operations in |handler|. The
-   * following NaCl IRT functions are async-signal-safe:
-   *
-   * - tls_get
-   * - futex_wait_abs
-   * - futex_wake
-   * - send_async_signal
-   *
-   * This function in particular is not async-signal-safe and must not be called
-   * from signal handlers.
-   */
-  int (*set_async_signal_handler)(NaClIrtAsyncSignalHandler handler);
-  /*
-   * Asynchronously delivers a signal to the thread identified by |tid| within
-   * the same process as the caller.  |tid| should be a valid thread identifier
-   * obtained when creating a thread (through the |child_tid| parameter to
-   * create_thread()) and the thread must still be alive.  The constant
-   * NACL_IRT_MAIN_THREAD_TID can be used to refer to the main thread.
-   *
-   * As opposed to POSIX, NaCl only provides a way to send a single signal.
-   * Delivery of different kinds of signals to be POSIX-compliant can be
-   * implemented in userspace.
-   *
-   * When |tid| is invalid, the result is unspecified.  This IRT function
-   * returns 0 on success or may return ESRCH or EINVAL on failure.
-   */
-  int (*send_async_signal)(nacl_irt_tid_t tid);
-};
-
 #if defined(__cplusplus)
 }
 #endif