Mirror cupsEnumDests change from 2.x to use cupsGetClock.

Author: michaelrsweet

CHANGES.md

@@ -5,6 +5,7 @@ libcups v3.0.0 (YYYY-MM-DD)
 ---------------------------
 
 - Fixed return values of `ippDateToTime` when the timezone isn't GMT.
+- Fixed a potential timing issue with `cupsEnumDests`.
 
 
 libcups v3.0rc4 (2025-03-18)

cups/clock.c

@@ -1,7 +1,7 @@
 //
 // Monotonic clock API for CUPS.
 //
-// Copyright © 2024 by OpenPrinting.
+// Copyright © 2024-2025 by OpenPrinting.
 //
 // Licensed under Apache License v2.0.  See the file "LICENSE" for more
 // information.
@@ -20,9 +20,9 @@ static cups_mutex_t cups_clock_mutex = CUPS_MUTEX_INITIALIZER;
 #ifdef _WIN32
 static ULONGLONG cups_first_tick;	// First tick count
 #else
-#  ifdef CLOCK_MONOTONIC
+#  if defined(CLOCK_MONOTONIC) || defined(CLOCK_MONOTONIC_RAW)
 static struct timespec cups_first_clock;// First clock value
-#  endif // CLOCK_MONOTONIC
+#  endif // CLOCK_MONOTONIC || CLOCK_MONOTONIC_RAW
 static struct timeval cups_first_time;	// First time value
 #endif // _WIN32
 
@@ -44,9 +44,9 @@ cupsGetClock(void)
 #ifdef _WIN32
   ULONGLONG	curtick;		// Current tick count
 #else
-#  ifdef CLOCK_MONOTONIC
+#  if defined(CLOCK_MONOTONIC) || defined(CLOCK_MONOTONIC_RAW)
   struct timespec curclock;		// Current clock value
-#  endif // CLOCK_MONOTONIC
+#  endif // CLOCK_MONOTONIC || CLOCK_MONOTONIC_RAW
   struct timeval curtime;		// Current time value
 #endif // _WIN32
 
@@ -71,9 +71,13 @@ cupsGetClock(void)
     secs = 0.001 * (curtick - cups_first_tick);
 
 #else
-#  ifdef CLOCK_MONOTONIC
+#  if defined(CLOCK_MONOTONIC) || defined(CLOCK_MONOTONIC_RAW)
   // Get the current tick count in milliseconds...
+#    ifdef CLOCK_MONOTONIC_RAW
+  if (!clock_gettime(CLOCK_MONOTONIC_RAW, &curclock))
+#    else
   if (!clock_gettime(CLOCK_MONOTONIC, &curclock))
+#    endif // CLOCK_MONOTONIC_RAW
   {
     if (!cups_clock_init)
     {

cups/dest.c

@@ -87,7 +87,7 @@ typedef struct _cups_dnssd_device_s	// Enumerated device
 typedef struct _cups_dnssd_resdata_s	// Data for resolving URI
 {
   int			*cancel;	// Pointer to "cancel" variable
-  struct timeval	end_time;	// Ending time
+  double		end_time;	// Ending time
 } _cups_dnssd_resdata_t;
 
 typedef struct _cups_getdata_s
@@ -129,7 +129,7 @@ static void		cups_dest_query_cb(cups_dnssd_query_t *query, void *cb_data, cups_d
 static const char	*cups_dest_resolve(cups_dest_t *dest, const char *uri, int msec, int *cancel, cups_dest_cb_t cb, void *user_data);
 static bool		cups_dest_resolve_cb(void *context);
 static void		cups_dnssd_unquote(char *dst, const char *src, size_t dstsize);
-static int		cups_elapsed(struct timeval *t);
+static int		cups_elapsed(double *t);
 static bool		cups_enum_dests(http_t *http, unsigned flags, int msec, int *cancel, cups_ptype_t type, cups_ptype_t mask, cups_dest_cb_t cb, void *user_data);
 static size_t		cups_find_dest(const char *name, const char *instance, size_t num_dests, cups_dest_t *dests, size_t prev, int *rdiff);
 static bool		cups_get_cb(_cups_getdata_t *data, unsigned flags, cups_dest_t *dest);
@@ -2517,23 +2517,12 @@ cups_dest_resolve(
 
 
   // Resolve the URI...
-  resolve.cancel = cancel;
-  gettimeofday(&resolve.end_time, NULL);
+  resolve.cancel   = cancel;
+  resolve.end_time = cupsGetClock();
   if (msec > 0)
-  {
-    resolve.end_time.tv_sec  += msec / 1000;
-    resolve.end_time.tv_usec += (msec % 1000) * 1000;
-
-    while (resolve.end_time.tv_usec >= 1000000)
-    {
-      resolve.end_time.tv_sec ++;
-      resolve.end_time.tv_usec -= 1000000;
-    }
-  }
+    resolve.end_time += 0.001 * msec;
   else
-  {
-    resolve.end_time.tv_sec += 75;
-  }
+    resolve.end_time += 75;
 
   if (cb)
     (*cb)(user_data, CUPS_DEST_FLAGS_UNCONNECTED | CUPS_DEST_FLAGS_RESOLVING, dest);
@@ -2564,7 +2553,7 @@ cups_dest_resolve_cb(void *context)	// I - Resolve data
 {
   _cups_dnssd_resdata_t	*resolve = (_cups_dnssd_resdata_t *)context;
 					// Resolve data
-  struct timeval	curtime;	// Current time
+  double		curtime;	// Current time
 
 
   // If the cancel variable is set, return immediately.
@@ -2575,11 +2564,11 @@ cups_dest_resolve_cb(void *context)	// I - Resolve data
   }
 
   // Otherwise check the end time...
-  gettimeofday(&curtime, NULL);
+  curtime = cupsGetClock();
 
-  DEBUG_printf("4cups_dest_resolve_cb: curtime=%d.%06d, end_time=%d.%06d", (int)curtime.tv_sec, (int)curtime.tv_usec, (int)resolve->end_time.tv_sec, (int)resolve->end_time.tv_usec);
+  DEBUG_printf("4cups_dest_resolve_cb: curtime=%.6f, end_time=%6f", curtime, resolve->end_time);
 
-  return (curtime.tv_sec < resolve->end_time.tv_sec || (curtime.tv_sec == resolve->end_time.tv_sec && curtime.tv_usec < resolve->end_time.tv_usec));
+  return (curtime < resolve->end_time);
 }
 
 
@@ -2625,17 +2614,15 @@ cups_dnssd_unquote(char       *dst,	// I - Destination buffer
 //
 
 static int				// O  - Elapsed time in milliseconds
-cups_elapsed(struct timeval *t)		// IO - Previous time
+cups_elapsed(double *t)			// IO - Previous time
 {
-  int			msecs;		// Milliseconds
-  struct timeval	nt;		// New time
-
-
-  gettimeofday(&nt, NULL);
+  int		msecs;			// Milliseconds
+  double	nt;			// New time
 
-  msecs = (int)(1000 * (nt.tv_sec - t->tv_sec) + (nt.tv_usec - t->tv_usec) / 1000);
 
-  *t = nt;
+  nt    = cupsGetClock();
+  msecs = (int)(1000.0 * (nt - *t));
+  *t    = nt;
 
   return (msecs);
 }
@@ -2667,7 +2654,7 @@ cups_enum_dests(
   size_t	count,			// Number of queries started
 		completed;		// Number of completed queries
   int		remaining;		// Remainder of timeout
-  struct timeval curtime;               // Current time
+  double	curtime;               // Current time
   _cups_dnssd_data_t data;		// Data for callback
   _cups_dnssd_device_t *device;         // Current device
   cups_dnssd_t	*dnssd = NULL;		// DNS-SD context
@@ -2900,7 +2887,7 @@ cups_enum_dests(
   else
     remaining = msec;
 
-  gettimeofday(&curtime, NULL);
+  curtime = cupsGetClock();
 
   while (remaining > 0 && (!cancel || !*cancel))
   {