ignore SIGPIPE in qemu-img and qemu-io

This prevents the tools from being stopped when they write data to a
closed connection in the other side.

Signed-off-by: MORITA Kazutaka <morita.kazutaka@lab.ntt.co.jp>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>

qemu-img.c

@@ -2322,6 +2322,10 @@ int main(int argc, char **argv)
     const img_cmd_t *cmd;
     const char *cmdname;
 
+#ifdef CONFIG_POSIX
+    signal(SIGPIPE, SIG_IGN);
+#endif
+
     error_set_progname(argv[0]);
 
     qemu_init_main_loop();

qemu-io.c

@@ -335,6 +335,10 @@ int main(int argc, char **argv)
     int opt_index = 0;
     int flags = BDRV_O_UNMAP;
 
+#ifdef CONFIG_POSIX
+    signal(SIGPIPE, SIG_IGN);
+#endif
+
     progname = basename(argv[0]);
 
     while ((c = getopt_long(argc, argv, sopt, lopt, &opt_index)) != -1) {