various: assorted cleanups for safe_fork (#39661)

Follow-up for aad0d11e7c6f1f7dcc7b00173140c74b8abf88cc.

src/basic/process-util.c

@@ -1662,7 +1662,7 @@ int pidref_safe_fork_full(
                 }
 
                 if (ret_pid) {
-                        if (FLAGS_SET(flags, FORK_PID_ONLY))
+                        if (FLAGS_SET(flags, _FORK_PID_ONLY))
                                 *ret_pid = PIDREF_MAKE_FROM_PID(pid);
                         else {
                                 r = pidref_set_pid(ret_pid, pid);
@@ -1840,7 +1840,7 @@ int pidref_safe_fork_full(
                 freeze();
 
         if (ret_pid) {
-                if (FLAGS_SET(flags, FORK_PID_ONLY))
+                if (FLAGS_SET(flags, _FORK_PID_ONLY))
                         *ret_pid = PIDREF_MAKE_FROM_PID(getpid_cached());
                 else {
                         r = pidref_set_self(ret_pid);
@@ -1869,7 +1869,7 @@ int safe_fork_full(
          * a pidref to the caller. */
         assert(!FLAGS_SET(flags, FORK_DETACH) || !ret_pid);
 
-        r = pidref_safe_fork_full(name, stdio_fds, except_fds, n_except_fds, flags|FORK_PID_ONLY, ret_pid ? &pidref : NULL);
+        r = pidref_safe_fork_full(name, stdio_fds, except_fds, n_except_fds, flags|_FORK_PID_ONLY, ret_pid ? &pidref : NULL);
         if (r < 0 || !ret_pid)
                 return r;
 

src/basic/process-util.h

@@ -187,7 +187,8 @@ typedef enum ForkFlags {
         FORK_NEW_NETNS          = 1 << 20, /* Run child in its own network namespace                             💣 DO NOT USE IN THREADED PROGRAMS! 💣 */
         FORK_NEW_PIDNS          = 1 << 21, /* Run child in its own PID namespace                                 💣 DO NOT USE IN THREADED PROGRAMS! 💣 */
         FORK_FREEZE             = 1 << 22, /* Don't return in child, just call freeze() instead */
-        FORK_PID_ONLY           = 1 << 23, /* Don't open a pidfd referencing the child process */
+
+        _FORK_PID_ONLY          = 1 << 23, /* Don't open a pidfd referencing the child process */
 } ForkFlags;
 
 int pidref_safe_fork_full(

src/notify/notify.c

@@ -520,7 +520,7 @@ static int action_fork(char *const *_command) {
                         /* stdio_fds= */ (const int[]) { -EBADF, -EBADF, STDERR_FILENO },
                         /* except_fds= */ NULL,
                         /* n_except_fds= */ 0,
-                        /* flags= */ FORK_REARRANGE_STDIO,
+                        /* flags= */ FORK_REARRANGE_STDIO|FORK_LOG,
                         &child);
         if (r < 0)
                 return log_error_errno(r, "Failed to fork child in order to execute '%s': %m", c);

src/shared/dissect-image.c

@@ -118,6 +118,7 @@ int dissect_fstype_ok(const char *fstype) {
         return false;
 }
 
+#if HAVE_BLKID
 static const char *getenv_fstype(PartitionDesignator d) {
 
         if (d < 0 ||
@@ -128,6 +129,7 @@ static const char *getenv_fstype(PartitionDesignator d) {
         char *v = strjoina("SYSTEMD_DISSECT_FSTYPE_", partition_designator_to_string(d));
         return secure_getenv(ascii_strupper(v));
 }
+#endif
 
 int probe_sector_size(int fd, uint32_t *ret) {
 

src/shared/hostname-setup.c

@@ -377,7 +377,7 @@ int pidref_gethostname_full(PidRef *pidref, GetHostnameFlags flags, char **ret)
                 return -errno;
 
         _cleanup_(pidref_done_sigkill_wait) PidRef child = PIDREF_NULL;
-        r = pidref_safe_fork("(gethostname)", FORK_RESET_SIGNALS|FORK_DEATHSIG_SIGKILL, &child);
+        r = pidref_safe_fork("(sd-gethostname)", FORK_RESET_SIGNALS|FORK_DEATHSIG_SIGKILL, &child);
         if (r < 0)
                 return r;
         if (r == 0) {