dbg: mutex should be unlocked while calling print handler

[alfredh]

No description provided.

[cspiel1]

Wouldn't this make the mutex ineffective?

If dbg output goes to stdout from multiple threads, then the lines could be mixed.

[alfredh]

this is a good question.

stdout is line-buffered and stderr has no buffering.

This patch is about the print handler. It makes sure that the mutex lock is unlocked while calling
the print handler, in case the print handler should call any functions in the re_dbg.h API.

The dbg code does not have any control of what the print_handler is doing.
In general it is good practice to unlock a mutex before calling a callback handler ...

[cspiel1]

Okay. I see now that dbg_lock protects dbg_vprintf() and dbg_init() against concurrency.

[cspiel1]

Would does this locking protect?

[cspiel1]

Should there be an additional lock in dbg_handler_set()?

[alfredh]

The mutex should protect all members of the struct.

[alfredh]

/** Debug configuration */
static struct {
	uint64_t tick;         /**< Init ticks             */
	int level;             /**< Current debug level    */
	enum dbg_flags flags;  /**< Debug flags            */
	dbg_print_h *ph;       /**< Optional print handler */
	void *arg;             /**< Handler argument       */
} dbg = {
	0,
	DBG_INFO,
	DBG_ANSI,
	NULL,
	NULL,
};

[cspiel1]

Looks good now

[alfredh]

@sreimers please merge to main if you agree ..