terminal-util: rework acquire_terminal()

This modernizes acquire_terminal() in a couple of ways:

1. The three boolean arguments are replaced by a flags parameter, that
   should be more descriptive in what it does.

2. We now properly handle inotify queue overruns

3. We use _cleanup_ for closing the fds now, to shorten the code quite a
   bit.

Behaviour should not be altered by this.

1 files changed, 17 insertions, 1 deletions

diff --git a/src/basic/terminal-util.h b/src/basic/terminal-util.h
index e82719b11b..257dbe71da 100644
--- a/src/basic/terminal-util.h
+++ b/src/basic/terminal-util.h
@@ -52,7 +52,23 @@ int reset_terminal_fd(int fd, bool switch_to_text);
 int reset_terminal(const char *name);
 
 int open_terminal(const char *name, int mode);
-int acquire_terminal(const char *name, bool fail, bool force, bool ignore_tiocstty_eperm, usec_t timeout);
+
+/* Flags for tweaking the way we become the controlling process of a terminal. */
+typedef enum AcquireTerminalFlags {
+        /* Try to become the controlling process of the TTY. If we can't return -EPERM. */
+        ACQUIRE_TERMINAL_TRY = 0,
+
+        /* Tell the kernel to forcibly make us the controlling process of the TTY. Returns -EPERM if the kernel doesn't allow that. */
+        ACQUIRE_TERMINAL_FORCE = 1,
+
+        /* If we can't become the controlling process of the TTY right-away, then wait until we can. */
+        ACQUIRE_TERMINAL_WAIT = 2,
+
+        /* Pick one of the above, and then OR this flag in, in order to request permissive behaviour, if we can't become controlling process then don't mind */
+        ACQUIRE_TERMINAL_PERMISSIVE = 4,
+} AcquireTerminalFlags;
+
+int acquire_terminal(const char *name, AcquireTerminalFlags flags, usec_t timeout);
 int release_terminal(void);
 
 int terminal_vhangup_fd(int fd);