util: replace close_nointr_nofail() by a more useful safe_close()

safe_close() automatically becomes a NOP when a negative fd is passed,
and returns -1 unconditionally. This makes it easy to write lines like
this:

        fd = safe_close(fd);

Which will close an fd if it is open, and reset the fd variable
correctly.

By making use of this new scheme we can drop a > 200 lines of code that
was required to test for non-negative fds or to reset the closed fd
variable afterwards.

1 files changed, 3 insertions, 4 deletions

diff --git a/src/core/machine-id-setup.c b/src/core/machine-id-setup.c
index 43720d6289..d459afe900 100644
--- a/src/core/machine-id-setup.c
+++ b/src/core/machine-id-setup.c
@@ -78,7 +78,7 @@ static int generate(char id[34], const char *root) {
         fd = open(dbus_machine_id, O_RDONLY|O_CLOEXEC|O_NOCTTY|O_NOFOLLOW);
         if (fd >= 0) {
                 k = loop_read(fd, id, 33, false);
-                close_nointr_nofail(fd);
+                safe_close(fd);
 
                 if (k == 33 && id[32] == '\n') {
 
@@ -104,7 +104,7 @@ static int generate(char id[34], const char *root) {
                 fd = open("/sys/class/dmi/id/product_uuid", O_RDONLY|O_CLOEXEC|O_NOCTTY|O_NOFOLLOW);
                 if (fd >= 0) {
                         k = loop_read(fd, uuid, 36, false);
-                        close_nointr_nofail(fd);
+                        safe_close(fd);
 
                         if (k >= 36) {
                                 r = shorten_uuid(id, uuid);
@@ -216,8 +216,7 @@ int machine_id_setup(const char *root) {
                         return 0;
         }
 
-        close_nointr_nofail(fd);
-        fd = -1;
+        fd = safe_close(fd);
 
         /* Hmm, we couldn't write it? So let's write it to
          * /run/machine-id as a replacement */