Copy siginfo_t to step before calling a user-space signal handler

git-svn-id: svn://svn.code.sf.net/p/nuttx/code/trunk@5769 42af7a65-404d-4744-a932-0658087f49c3

ChangeLog

@@ -4410,4 +4410,9 @@
 	  all system call inline functions with > 3 parameters (2013-03-20)
 	* arch/*/src/common/up_stackframe.c and include/nuttx/arch.h:  Add
 	  and new interface to set aside memory on the stack.  This will be
-	  used at least in the kernel build to hold task arguments 2013-03-21).
+	  used at least in the kernel build to hold task arguments (2013-03-21).
+	* sched/sig_deliver.c:  When dispatching signals to user threads,
+	  copy the siginfo_t from the sigq to the stack.  The signal queue
+	  is allocated from kernel memory; however, the current stack is
+	  the user's stack and the user code will be able to access the
+	  signinfo_t data from the stack copy (2013-03-21).

Documentation/NuttxPortingGuide.html

@@ -1713,7 +1713,7 @@ The system can be re-made subsequently by just typing <code>make</code>.
   This function may be called anytime after <code>up_create_stack()</code> or <code>up_use_stack()</code> have been called but before the task has been started.
 </p>
 <p>
-  Thread data may be kept in the stack (instead of in the TCB) if it is accessed by the user code directory.
+  Thread data may be kept in the stack (instead of in the TCB) if it is accessed by the user code directly.
   This includes such things as <code>argv[]</code>.
   The stack memory is guaranteed to be in the same protection domain as the thread.
 </p>

arch/arm/src/common/up_stackframe.c

@@ -96,7 +96,7 @@
  *   up_use_stack() have been called but before the task has been started.
  *
  *   Thread data may be kept in the stack (instead of in the TCB) if it is
- *   accessed by the user code directory.  This includes such things as
+ *   accessed by the user code directly.  This includes such things as
  *   argv[].  The stack memory is guaranteed to be in the same protection
  *   domain as the thread.
  *

arch/avr/src/avr/up_stackframe.c

@@ -73,7 +73,7 @@
  *   up_use_stack() have been called but before the task has been started.
  *
  *   Thread data may be kept in the stack (instead of in the TCB) if it is
- *   accessed by the user code directory.  This includes such things as
+ *   accessed by the user code directly.  This includes such things as
  *   argv[].  The stack memory is guaranteed to be in the same protection
  *   domain as the thread.
  *

arch/avr/src/avr32/up_stackframe.c

@@ -85,7 +85,7 @@
  *   up_use_stack() have been called but before the task has been started.
  *
  *   Thread data may be kept in the stack (instead of in the TCB) if it is
- *   accessed by the user code directory.  This includes such things as
+ *   accessed by the user code directly.  This includes such things as
  *   argv[].  The stack memory is guaranteed to be in the same protection
  *   domain as the thread.
  *

arch/hc/src/common/up_stackframe.c

@@ -85,7 +85,7 @@
  *   up_use_stack() have been called but before the task has been started.
  *
  *   Thread data may be kept in the stack (instead of in the TCB) if it is
- *   accessed by the user code directory.  This includes such things as
+ *   accessed by the user code directly.  This includes such things as
  *   argv[].  The stack memory is guaranteed to be in the same protection
  *   domain as the thread.
  *

arch/mips/src/common/up_stackframe.c

@@ -88,7 +88,7 @@
  *   up_use_stack() have been called but before the task has been started.
  *
  *   Thread data may be kept in the stack (instead of in the TCB) if it is
- *   accessed by the user code directory.  This includes such things as
+ *   accessed by the user code directly.  This includes such things as
  *   argv[].  The stack memory is guaranteed to be in the same protection
  *   domain as the thread.
  *

arch/sh/src/common/up_stackframe.c

@@ -84,7 +84,7 @@
  *   up_use_stack() have been called but before the task has been started.
  *
  *   Thread data may be kept in the stack (instead of in the TCB) if it is
- *   accessed by the user code directory.  This includes such things as
+ *   accessed by the user code directly.  This includes such things as
  *   argv[].  The stack memory is guaranteed to be in the same protection
  *   domain as the thread.
  *

arch/sim/src/up_stackframe.c

@@ -85,7 +85,7 @@
  *   up_use_stack() have been called but before the task has been started.
  *
  *   Thread data may be kept in the stack (instead of in the TCB) if it is
- *   accessed by the user code directory.  This includes such things as
+ *   accessed by the user code directly.  This includes such things as
  *   argv[].  The stack memory is guaranteed to be in the same protection
  *   domain as the thread.
  *

arch/x86/src/i486/up_stackframe.c

@@ -86,7 +86,7 @@
  *   up_use_stack() have been called but before the task has been started.
  *
  *   Thread data may be kept in the stack (instead of in the TCB) if it is
- *   accessed by the user code directory.  This includes such things as
+ *   accessed by the user code directly.  This includes such things as
  *   argv[].  The stack memory is guaranteed to be in the same protection
  *   domain as the thread.
  *

arch/z16/src/common/up_stackframe.c

@@ -84,7 +84,7 @@
  *   up_use_stack() have been called but before the task has been started.
  *
  *   Thread data may be kept in the stack (instead of in the TCB) if it is
- *   accessed by the user code directory.  This includes such things as
+ *   accessed by the user code directly.  This includes such things as
  *   argv[].  The stack memory is guaranteed to be in the same protection
  *   domain as the thread.
  *

arch/z80/src/common/up_stackframe.c

@@ -84,7 +84,7 @@
  *   up_use_stack() have been called but before the task has been started.
  *
  *   Thread data may be kept in the stack (instead of in the TCB) if it is
- *   accessed by the user code directory.  This includes such things as
+ *   accessed by the user code directly.  This includes such things as
  *   argv[].  The stack memory is guaranteed to be in the same protection
  *   domain as the thread.
  *

include/nuttx/arch.h

@@ -228,7 +228,7 @@ int up_use_stack(FAR struct tcb_s *tcb, FAR void *stack, size_t stack_size);
  *   up_use_stack() have been called but before the task has been started.
  *
  *   Thread data may be kept in the stack (instead of in the TCB) if it is
- *   accessed by the user code directory.  This includes such things as
+ *   accessed by the user code directly.  This includes such things as
  *   argv[].  The stack memory is guaranteed to be in the same protection
  *   domain as the thread.
  *

sched/sig_deliver.c

@@ -136,12 +136,25 @@ void sig_deliver(FAR struct tcb_s *stcb)
 #ifdef CONFIG_NUTTX_KERNEL
       if ((stcb->flags & TCB_FLAG_TTYPE_MASK) != TCB_FLAG_TTYPE_KERNEL)
         {
+          /* The sigq_t pointed to by sigq resides in kernel space.  So we
+           * cannot pass a reference to sigq->info to the user space.
+           * Instead, we will copy the siginfo_t structure onto that stack.
+           * We are currently executing on the stack of the user thread
+           * (albeit temporarily in kernel mode), so the copy of the
+           * siginfo_t structure will be accessible by the user thread.
+           */
+
+          siginfo_t info;
+          memcpy(&info, sigq->info, sizeof(siginfo_t));
+
           up_signal_handler(sigq->action.sighandler, sigq->info.si_signo,
-                            &sigq->info, NULL);
+                            &info, NULL);
         }
       else
 #endif
         {
+          /* The kernel thread signal handler is much simpler. */
+
           (*sigq->action.sighandler)(sigq->info.si_signo, &sigq->info,
                                      NULL);
         }