bsd-user/signal.c: Add si_type argument to queue_signal

Mirror the linux-user practice and add a si_type argument to queue
signal. This will be transported as the upper 8 bits in the si_type
element of siginfo so that we know what bits of the structure are valid
and so we can properly implement host_to_target_siginfo_noswap and
tswap_siginfo. Adapt the one caller of queue_signal to the new
interface.  Use all the same names as Linux (except _RT which we don't
treat differently, unlike Linux), though some are unused. Place this
into signal-common.h since that's a better place given bsd-user's
structure. Move prototype of queue_signal to signal-common.h to mirror
linux-user's location.

Signed-off-by: Warner Losh <imp@bsdimp.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>

bsd-user/signal-common.h

@@ -15,8 +15,32 @@ long do_sigreturn(CPUArchState *env);
 void force_sig_fault(int sig, int code, abi_ulong addr);
 int host_to_target_signal(int sig);
 void process_pending_signals(CPUArchState *env);
-void queue_signal(CPUArchState *env, int sig, target_siginfo_t *info);
+void queue_signal(CPUArchState *env, int sig, int si_type,
+                  target_siginfo_t *info);
 void signal_init(void);
 int target_to_host_signal(int sig);
 
+/*
+ * Within QEMU the top 8 bits of si_code indicate which of the parts of the
+ * union in target_siginfo is valid. This only applies between
+ * host_to_target_siginfo_noswap() and tswap_siginfo(); it does not appear
+ * either within host siginfo_t or in target_siginfo structures which we get
+ * from the guest userspace program. Linux kenrels use this internally, but BSD
+ * kernels don't do this, but its a useful abstraction.
+ *
+ * The linux-user version of this uses the top 16 bits, but FreeBSD's SI_USER
+ * and other signal indepenent SI_ codes have bit 16 set, so we only use the top
+ * byte instead.
+ *
+ * For FreeBSD, we have si_pid, si_uid, si_status, and si_addr always. Linux and
+ * {Open,Net}BSD have a different approach (where their reason field is larger,
+ * but whose siginfo has fewer fields always).
+ */
+#define QEMU_SI_NOINFO   0      /* nothing other than si_signo valid */
+#define QEMU_SI_FAULT    1      /* _fault is valid in _reason */
+#define QEMU_SI_TIMER    2      /* _timer is valid in _reason */
+#define QEMU_SI_MESGQ    3      /* _mesgq is valid in _reason */
+#define QEMU_SI_POLL     4      /* _poll is valid in _reason */
+#define QEMU_SI_CAPSICUM 5      /* _capsicum is valid in _reason */
+
 #endif

bsd-user/signal.c

@@ -50,7 +50,8 @@ int target_to_host_signal(int sig)
  * Queue a signal so that it will be send to the virtual CPU as soon as
  * possible.
  */
-void queue_signal(CPUArchState *env, int sig, target_siginfo_t *info)
+void queue_signal(CPUArchState *env, int sig, int si_type,
+                  target_siginfo_t *info)
 {
     qemu_log_mask(LOG_UNIMP, "No signal queueing, dropping signal %d\n", sig);
 }
@@ -91,7 +92,7 @@ void force_sig_fault(int sig, int code, abi_ulong addr)
     info.si_errno = 0;
     info.si_code = code;
     info.si_addr = addr;
-    queue_signal(env, sig, &info);
+    queue_signal(env, sig, QEMU_SI_FAULT, &info);
 }
 
 static void host_signal_handler(int host_sig, siginfo_t *info, void *puc)