cpus: remove ugly cast on sigbus_handler

The cast is there because sigbus_handler is invoked via sigfd_handler.
But it feels just wrong to use struct qemu_signalfd_siginfo in the
prototype of a function that is passed to sigaction.

Instead, do a simple-minded conversion of qemu_signalfd_siginfo to
siginfo_t.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

3 files changed, 34 insertions, 5 deletions

diff --git a/util/compatfd.c b/util/compatfd.c
index 9a43042..980bd33 100644
--- a/util/compatfd.c
+++ b/util/compatfd.c
@@ -15,7 +15,6 @@
 
 #include "qemu/osdep.h"
 #include "qemu-common.h"
-#include "qemu/compatfd.h"
 #include "qemu/thread.h"
 
 #include <sys/syscall.h>
diff --git a/util/main-loop.c b/util/main-loop.c
index ad10bca..ca7bb07 100644
--- a/util/main-loop.c
+++ b/util/main-loop.c
@@ -34,8 +34,6 @@
 
 #ifndef _WIN32
 
-#include "qemu/compatfd.h"
-
 /* If we have signalfd, we mask out the signals we want to handle and then
  * use signalfd to listen for them.  We rely on whatever the current signal
  * handler is to dispatch the signals when we receive them.
@@ -63,8 +61,7 @@ static void sigfd_handler(void *opaque)
 
         sigaction(info.ssi_signo, NULL, &action);
         if ((action.sa_flags & SA_SIGINFO) && action.sa_sigaction) {
-            action.sa_sigaction(info.ssi_signo,
-                                (siginfo_t *)&info, NULL);
+            sigaction_invoke(&action, &info);
         } else if (action.sa_handler) {
             action.sa_handler(info.ssi_signo);
         }
diff --git a/util/oslib-posix.c b/util/oslib-posix.c
index f631464..cd686aa 100644
--- a/util/oslib-posix.c
+++ b/util/oslib-posix.c
@@ -603,3 +603,36 @@ void qemu_free_stack(void *stack, size_t sz)
 
     munmap(stack, sz);
 }
+
+void sigaction_invoke(struct sigaction *action,
+                      struct qemu_signalfd_siginfo *info)
+{
+    siginfo_t si = { 0 };
+    si.si_signo = info->ssi_signo;
+    si.si_errno = info->ssi_errno;
+    si.si_code = info->ssi_code;
+
+    /* Convert the minimal set of fields defined by POSIX.
+     * Positive si_code values are reserved for kernel-generated
+     * signals, where the valid siginfo fields are determined by
+     * the signal number.  But according to POSIX, it is unspecified
+     * whether SI_USER and SI_QUEUE have values less than or equal to
+     * zero.
+     */
+    if (info->ssi_code == SI_USER || info->ssi_code == SI_QUEUE ||
+        info->ssi_code <= 0) {
+        /* SIGTERM, etc.  */
+        si.si_pid = info->ssi_pid;
+        si.si_uid = info->ssi_uid;
+    } else if (info->ssi_signo == SIGILL || info->ssi_signo == SIGFPE ||
+               info->ssi_signo == SIGSEGV || info->ssi_signo == SIGBUS) {
+        si.si_addr = (void *)(uintptr_t)info->ssi_addr;
+    } else if (info->ssi_signo == SIGCHLD) {
+        si.si_pid = info->ssi_pid;
+        si.si_status = info->ssi_status;
+        si.si_uid = info->ssi_uid;
+    } else if (info->ssi_signo == SIGIO) {
+        si.si_band = info->ssi_band;
+    }
+    action->sa_sigaction(info->ssi_signo, &si, NULL);
+}