Add macro for checking if some flags are set

This way we don't need to repeat the argument twice.
I didn't replace all instances. I think it's better to leave out:
- asserts
- comparisons like x & y == x, which are mathematically equivalent, but
  here we aren't checking if flags are set, but if the argument fits in the
  flags.

src/basic/capability-util.h

@@ -41,7 +41,7 @@ static inline void cap_free_charpp(char **p) {
 static inline bool cap_test_all(uint64_t caps) {
         uint64_t m;
         m = (UINT64_C(1) << (cap_last_cap() + 1)) - 1;
-        return (caps & m) == m;
+        return FLAGS_SET(caps, m);
 }
 
 bool ambient_capabilities_supported(void);

src/basic/copy.c

@@ -81,7 +81,7 @@ static int fd_is_nonblock_pipe(int fd) {
         if (flags < 0)
                 return -errno;
 
-        return (flags & O_NONBLOCK) == O_NONBLOCK ? FD_IS_NONBLOCKING_PIPE : FD_IS_BLOCKING_PIPE;
+        return FLAGS_SET(flags, O_NONBLOCK) ? FD_IS_NONBLOCKING_PIPE : FD_IS_BLOCKING_PIPE;
 }
 
 int copy_bytes_full(

src/basic/fs-util.c

@@ -602,10 +602,10 @@ int chase_symlinks(const char *path, const char *original_root, unsigned flags,
         assert(path);
 
         /* Either the file may be missing, or we return an fd to the final object, but both make no sense */
-        if ((flags & (CHASE_NONEXISTENT|CHASE_OPEN)) == (CHASE_NONEXISTENT|CHASE_OPEN))
+        if (FLAGS_SET(flags, CHASE_NONEXISTENT | CHASE_OPEN))
                 return -EINVAL;
 
-        if ((flags & (CHASE_STEP|CHASE_OPEN)) == (CHASE_STEP|CHASE_OPEN))
+        if (FLAGS_SET(flags, CHASE_STEP | CHASE_OPEN))
                 return -EINVAL;
 
         if (isempty(path))

src/basic/macro.h

@@ -357,6 +357,8 @@ static inline unsigned long ALIGN_POWER2(unsigned long u) {
 
 #define SET_FLAG(v, flag, b) \
         (v) = (b) ? ((v) | (flag)) : ((v) & ~(flag))
+#define FLAGS_SET(v, flags) \
+        (((v) & (flags)) == (flags))
 
 #define CASE_F(X) case X:
 #define CASE_F_1(CASE, X) CASE_F(X)

src/basic/process-util.c

@@ -1359,7 +1359,7 @@ int safe_fork_full(
                 }
         }
 
-        if ((flags & (FORK_NEW_MOUNTNS|FORK_MOUNTNS_SLAVE)) == (FORK_NEW_MOUNTNS|FORK_MOUNTNS_SLAVE)) {
+        if (FLAGS_SET(flags, FORK_NEW_MOUNTNS | FORK_MOUNTNS_SLAVE)) {
 
                 /* Optionally, make sure we never propagate mounts to the host. */
 

src/basic/rm-rf.c

@@ -178,7 +178,7 @@ int rm_rf(const char *path, RemoveFlags flags) {
                 return -EPERM;
         }
 
-        if ((flags & (REMOVE_SUBVOLUME|REMOVE_ROOT|REMOVE_PHYSICAL)) == (REMOVE_SUBVOLUME|REMOVE_ROOT|REMOVE_PHYSICAL)) {
+        if (FLAGS_SET(flags, REMOVE_SUBVOLUME | REMOVE_ROOT | REMOVE_PHYSICAL)) {
                 /* Try to remove as subvolume first */
                 r = btrfs_subvol_remove(path, BTRFS_REMOVE_RECURSIVE|BTRFS_REMOVE_QUOTA);
                 if (r >= 0)