Merge pull request #59 from mac-joker/master

New features: custom timestamp file and cache managment

README

@@ -169,14 +169,15 @@ will be loaded, but just report the real system time. There are three
 ways to specify the faked time:
 
 a) By setting the environment variable FAKETIME.
-b) By using the file .faketimerc in your home directory.
-c) By using the file /etc/faketimerc for a system-wide default.
+b) By using the file given in the environment variable FAKETIME_TIMESTAMP_FILE
+c) By using the file .faketimerc in your home directory.
+d) By using the file /etc/faketimerc for a system-wide default.
 
-If you want to use b) or c), $HOME/.faketimerc or /etc/faketimerc consist of
+If you want to use b) c) or d), $HOME/.faketimerc or /etc/faketimerc consist of
 only one line of text with exactly the same content as the FAKETIME environment
 variable, which is described below. Note that /etc/faketimerc will only be used
-if there is no $HOME/.faketimerc, and the FAKETIME environment variable always
-has priority over the files.
+if there is no $HOME/.faketimerc nor FAKETIME_TIMESTAMP_FILE file exists, and
+the FAKETIME environment variable always has priority over the files.
 
 
 4b) Using absolute dates
@@ -314,12 +315,14 @@ Using relative offsets or 'start at' dates solves this problem.
 libfaketime then will always report the faked time based on the real
 current time and the offset you've specified.
 
-Please also note that your specification of the fake time is cached for 10
-seconds in order to enhance the library's performance. Thus, if you change the
+Please also note that your default specification of the fake time is cached for
+10 seconds in order to enhance the library's performance. Thus, if you change the
 content of $HOME/.faketimerc or /etc/faketimerc while a program is running, it
 may take up to 10 seconds before the new fake time is applied. If this is a
-problem in your scenario, you can disable caching at compile time by adding the
-command line option -DNO_CACHING to this library's Makefile.
+problem in your scenario, you can change number of seconds before the file is read
+again with environment variable FAKETIME_CACHE_DURATION, or disable caching at all
+with FAKETIME_NO_CACHE=1. Remember that disabling the cache may negatively
+influence the performance.
 
 
 4f) Faking the date and time system-wide

src/Makefile

@@ -30,12 +30,6 @@
 #	  FAKE_TIMERS
 #	      - Also intercept timer_settime() and timer_gettime()
 #
-#     NO_CACHING
-#         - Disables the caching of the fake time offset. Only disable caching
-#           if you change the fake time offset during program runtime very
-#           frequently. Disabling the cache may negatively influence the
-#           performance.
-#
 #	  MULTI_ARCH
 #	  	  - If MULTI_ARCH is set, the faketime wrapper program will put a literal
 #	  	    $LIB into the LD_PRELOAD environment variable it creates, which makes

src/Makefile.OSX

@@ -21,12 +21,6 @@
 # 	  FAKE_SLEEP
 # 	      - Also intercept sleep(), nanosleep(), usleep(), alarm(), [p]poll()
 #
-#     NO_CACHING
-#         - Disables the caching of the fake time offset. Only disable caching
-#           if you change the fake time offset during program runtime very
-#           frequently. Disabling the cache may negatively influence the
-#           performance.
-#
 #   * Compilation addition: second libMT target added for building the pthread-
 #     enabled library as a separate library
 #

src/libfaketime.c

@@ -200,6 +200,8 @@ static long ft_spawn_secs = -1;
 static long ft_spawn_ncalls = -1;
 
 static int fake_monotonic_clock = 1;
+static int cache_enabled = 1;
+static int cache_duration = 10;     /* cache fake time input for 10 seconds */
 
 /*
  * Static timespec to store our startup time, followed by a load-time library
@@ -1460,6 +1462,17 @@ void __attribute__ ((constructor)) ftpl_init(void)
   }
 #endif
 
+  if ((tmp_env = getenv("FAKETIME_CACHE_DURATION")) != NULL)
+  {
+    cache_duration = atoi(tmp_env);
+  }
+  if ((tmp_env = getenv("FAKETIME_NO_CACHE")) != NULL)
+  {
+    if (0 == strcmp(tmp_env, "1"))
+    {
+      cache_enabled = 0;
+    }
+  }
   if ((tmp_env = getenv("DONT_FAKE_MONOTONIC")) != NULL)
   {
     if (0 == strcmp(tmp_env, "1"))
@@ -1676,7 +1689,6 @@ int fake_clock_gettime(clockid_t clk_id, struct timespec *tp)
   /* variables used for caching, introduced in version 0.6 */
   static time_t last_data_fetch = 0;  /* not fetched previously at first call */
   static int cache_expired = 1;       /* considered expired at first call */
-  static int cache_duration = 10;     /* cache fake time input for 10 seconds */
 
   if (dont_fake) return 0;
   /* Per process timers are only sped up or slowed down */
@@ -1762,9 +1774,10 @@ int fake_clock_gettime(clockid_t clk_id, struct timespec *tp)
     }
   }
 
-#ifdef NO_CACHING
-  cache_expired = 1;
-#endif
+  if (cache_enabled == 0)
+  {
+    cache_expired = 1;
+  }
 
   if (cache_expired == 1)
   {
@@ -1777,6 +1790,7 @@ int fake_clock_gettime(clockid_t clk_id, struct timespec *tp)
     if (parse_config_file)
     {
       static char user_faked_time[BUFFERLEN]; /* changed to static for caching in v0.6 */
+      char custom_filename[BUFSIZ];
       char filename[BUFSIZ];
       FILE *faketimerc;
       /* initialize with default or env. variable */
@@ -1794,8 +1808,10 @@ int fake_clock_gettime(clockid_t clk_id, struct timespec *tp)
        * a system-wide /etc/faketimerc present.
        * The /etc/faketimerc handling has been contributed by David Burley,
        * Jacob Moorman, and Wayne Davison of SourceForge, Inc. in version 0.6 */
+      (void) snprintf(custom_filename, BUFSIZ, "%s", getenv("FAKETIME_TIMESTAMP_FILE"));
       (void) snprintf(filename, BUFSIZ, "%s/.faketimerc", getenv("HOME"));
-      if ((faketimerc = fopen(filename, "rt")) != NULL ||
+      if ((faketimerc = fopen(custom_filename, "rt")) != NULL ||
+          (faketimerc = fopen(filename, "rt")) != NULL ||
           (faketimerc = fopen("/etc/faketimerc", "rt")) != NULL)
       {
         char line[BUFFERLEN];