implementations of dup3 and fallocate that are good enough to fool LTP

updated fallocate check to new configure, added dup3 check as suggested
by Jan-Simon Möller.

Riku: updated to apply to current git.
Signed-off-by: NUlrich Hecht <uli@suse.de>
Signed-off-by: NRiku Voipio <riku.voipio@iki.fi>

configure

@@ -1569,6 +1569,36 @@ if compile_prog "" "" ; then
   eventfd=yes
 fi
 
+# check for fallocate
+fallocate=no
+cat > $TMPC << EOF
+#include <fcntl.h>
+
+int main(void)
+{
+    fallocate(0, 0, 0, 0);
+    return 0;
+}
+EOF
+if $cc $ARCH_CFLAGS -o $TMPE $TMPC 2> /dev/null ; then
+  fallocate=yes
+fi
+
+# check for dup3
+dup3=no
+cat > $TMPC << EOF
+#include <unistd.h>
+
+int main(void)
+{
+    dup3(0, 0, 0);
+    return 0;
+}
+EOF
+if $cc $ARCH_CFLAGS -o $TMPE $TMPC 2> /dev/null ; then
+  dup3=yes
+fi
+
 # Check if tools are available to build documentation.
 if test "$docs" != "no" ; then
   if test -x "`which texi2html 2>/dev/null`" -a \
@@ -1950,6 +1980,12 @@ fi
 if test "$eventfd" = "yes" ; then
   echo "CONFIG_EVENTFD=y" >> $config_host_mak
 fi
+if test "$fallocate" = "yes" ; then
+  echo "CONFIG_FALLOCATE=y" >> $config_host_mak
+fi
+if test "$dup3" = "yes" ; then
+  echo "CONFIG_DUP3=y" >> $config_host_mak
+fi
 if test "$inotify" = "yes" ; then
   echo "CONFIG_INOTIFY=y" >> $config_host_mak
 fi

linux-user/syscall.c

@@ -4746,6 +4746,11 @@ abi_long do_syscall(void *cpu_env, int num, abi_long arg1,
     case TARGET_NR_dup2:
         ret = get_errno(dup2(arg1, arg2));
         break;
+#if defined(CONFIG_DUP3) && defined(TARGET_NR_dup3)
+    case TARGET_NR_dup3:
+        ret = get_errno(dup3(arg1, arg2, arg3));
+        break;
+#endif
 #ifdef TARGET_NR_getppid /* not on alpha */
     case TARGET_NR_getppid:
         ret = get_errno(getppid());
@@ -7013,6 +7018,11 @@ abi_long do_syscall(void *cpu_env, int num, abi_long arg1,
         break;
 #endif
 #endif /* CONFIG_EVENTFD  */
+#if defined(CONFIG_FALLOCATE) && defined(TARGET_NR_fallocate)
+    case TARGET_NR_fallocate:
+        ret = get_errno(fallocate(arg1, arg2, arg3, arg4));
+        break;
+#endif
     default:
     unimplemented:
         gemu_log("qemu: Unsupported syscall: %d\n", num);