support for SOURCE_DATE_EPOCH and utc -- code & manual

manual/luatex-lua.tex

@@ -56,44 +56,32 @@ similar fashion as the other \TEX\ engines. Some options are accepted but have n
 consequence. The following command|-|line options are understood:
 
 \starttabulate[|lT|p|]
+\NC --credits                    \NC display credits and exit \NC \NR
+\NC --debug-format               \NC enable format debugging \NC \NR
+\NC --draftmode                  \NC switch on draft mode i.e.\ generate no output in \PDF\ mode \NC \NR
+\NC --[no-]file-line-error       \NC disable/enable \type {file:line:error} style messages \NC \NR
+\NC --[no-]file-line-error-style \NC aliases of \type {--[no-]file-line-error} \NC \NR
 \NC --fmt=FORMAT                 \NC load the format file \type {FORMAT} \NC\NR
-\NC --lua=FILE                   \NC load and execute a \LUA\ initialization script\NC\NR
-\NC --safer                      \NC disable easily exploitable \LUA\ commands \NC\NR
-\NC --nosocket                   \NC disable the \LUA\ socket library \NC\NR
+\NC --halt-on-error              \NC stop processing at the first error\NC \NR
 \NC --help                       \NC display help and exit \NC\NR
 \NC --ini                        \NC be \type {iniluatex}, for dumping formats \NC\NR
-\NC --interaction=STRING         \NC set interaction mode: \type {batchmode}, \type {nonstopmode},
-                                     \type {scrollmode} or \type {errorstopmode} \NC \NR
-\NC --halt-on-error              \NC stop processing at the first error\NC \NR
-\NC --kpathsea-debug=NUMBER      \NC set path searching debugging flags according to
-                                     the bits of \type {NUMBER} \NC \NR
+\NC --interaction=STRING         \NC set interaction mode: \type {batchmode}, \type {nonstopmode}, \type {scrollmode} or \type {errorstopmode} \NC \NR
+\NC --jobname=STRING             \NC set the job name to \type {STRING} \NC \NR
+\NC --kpathsea-debug=NUMBER      \NC set path searching debugging flags according to the bits of \type {NUMBER} \NC \NR
+\NC --lua=FILE                   \NC load and execute a \LUA\ initialization script \NC\NR
+\NC --[no-]mktex=FMT             \NC disable/enable \type {mktexFMT} generation with \type {FMT} is \type {tex} or \type {tfm} \NC \NR
+\NC --nosocket                   \NC disable the \LUA\ socket library \NC\NR
+\NC --output-comment=STRING      \NC use \type {STRING} for \DVI\ file comment instead of date (no effect for \PDF) \NC \NR
+\NC --output-directory=DIR       \NC use \type {DIR} as the directory to write files to \NC \NR
+\NC --output-format=FORMAT       \NC use \type {FORMAT} for job output; \type {FORMAT} is \type {dvi} or \type {pdf} \NC \NR
 \NC --progname=STRING            \NC set the program name to \type {STRING} \NC \NR
-\NC --version                    \NC display version and exit \NC \NR
-\NC --credits                    \NC display credits and exit \NC \NR
 \NC --recorder                   \NC enable filename recorder \NC \NR
-\NC --output-comment=STRING      \NC use \type {STRING} for \DVI\ file comment
-                                     instead of date (no effect for \PDF) \NC \NR
-\NC --output-directory=DIR       \NC use \type {DIR} as the directory to write
-                                     files to \NC \NR
-\NC --draftmode                  \NC switch on draft mode i.e.\ generate no
-                                     output in \PDF\ mode \NC \NR
-\NC --output-format=FORMAT       \NC use \type {FORMAT} for job output; \type
-                                     {FORMAT} is \type {dvi} or \type {pdf} \NC
-                                     \NR
+\NC --safer                      \NC disable easily exploitable \LUA\ commands \NC\NR
 \NC --[no-]shell-escape          \NC disable/enable system calls \NC \NR
-\NC --enable-write18             \NC enable system calls \NC \NR
-\NC --disable-write18            \NC disable system calls \NC \NR
-\NC --shell-restricted           \NC restrict system calls to a list of commands
-                                     given in \type {texmf.cnf} \NC \NR
-\NC --debug-format               \NC enable format debugging \NC \NR
-\NC --[no-]file-line-error       \NC disable/enable \type {file:line:error} style
-                                     messages \NC \NR
-\NC --[no-]file-line-error-style \NC aliases of \type {--[no-]file-line-error} \NC \NR
-\NC --jobname=STRING             \NC set the job name to \type {STRING} \NC \NR
-\NC --[no-]mktex=FMT             \NC disable/enable \type {mktexFMT} generation
-                                     with \type {FMT} is \type {tex} or \type
-                                     {tfm} \NC \NR
+\NC --shell-restricted           \NC restrict system calls to a list of commands given in \type {texmf.cnf} \NC \NR
 \NC --synctex=NUMBER             \NC enable \type {synctex} \NC \NR
+\NC --utc                        \NC use utc times when applicable \NC \NR
+\NC --version                    \NC display version and exit \NC \NR
 \stoptabulate
 
 Some of the traditional flags are just ignored: \type {--etex}, \type
@@ -543,6 +531,42 @@ At some point (this also depends on distributions) \LUATEX\ might have these
 libraries loaded on demand. For this reason you can best use \type {require} to
 make sure they are loaded.
 
+\section{Testing}
+
+For development reasons you can influence the used startup date and time. This can
+be done in two ways.
+
+\startitemize[n]
+
+\startitem
+    By setting the environmment variable \type {SOURCE_DATE_EPOCH}. This will
+    influence the \TEX\ parameters \type {time} and \type {date}, the random seed,
+    the \PDF\ timestamp and the \PDF\ id that is derived from the time as well. This
+    variable is consulted when the \KPSE\ library is enabled. Resolving is
+    delegated to this library.
+\stopitem
+
+\startitem
+    By setting the \type {start_time} variable in the \type {texconfig} table; as
+    with other variables we use the internal name there. For compatibility
+    reasons we also honour a \type {SOURCE_DATE_EPOCH} entry. It should be noted
+    that there are no such variables in other engines and this method is only
+    relevant in case the while setup happens in \LUA.
+\stopitem
+
+\stopitemize
+
+When Universal Time is needed, you can pass the flag \type {utc} to the engine. This
+property also works when the date and time are set by \LUATEX\ itself. It has a
+complementary entry \type {use_utf_time} in the \type {texconfig} table.
+
+{\em To some extend a cleaner solution would be to have a flag that disables all
+variable data in one go (like filenames and so) but we just follow the method
+implemented in \PDFTEX\ where primitives are used to influence other properties.}
+
+{\em In \CONTEXT\ we provide the command line argument \type {--nodates} that
+does bit more disabling of dates.}
+
 \stopchapter
 
 \stopcomponent

manual/luatex.tex

@@ -3,10 +3,7 @@
 % \tex vs \type vs \syntax vs. \luatex
 % \em \it \/
 
-\startmode[nodates]
-    \enabledirectives[backend.date=no]
-    \nopdfcompression
-\stopmode
+% "context --nodates --nocompression luatex" can be used for comparison runs
 
 \environment luatex-style
 \environment luatex-logos

source/texk/web2c/luatexdir/lua/luainit.w

@@ -576,6 +576,7 @@ static void init_kpse(void)
 
     kpse_set_program_name(argv[0], user_progname);
     init_shell_escape();        /* set up 'restrictedshell' */
+    init_start_time();
     program_name_set = 1 ;
     if (recorderoption) {
         recorder_enabled = 1;
@@ -859,6 +860,8 @@ void lua_initialize(int ac, char **av)
     char *banner;
     int kpse_init;
     size_t len;
+    int starttime;
+    int utc;
     static char LC_CTYPE_C[] = "LC_CTYPE=C";
     static char LC_COLLATE_C[] = "LC_COLLATE=C";
     static char LC_NUMERIC_C[] = "LC_NUMERIC=C";
@@ -1035,6 +1038,25 @@ void lua_initialize(int ac, char **av)
             }
         }
 
+        starttime = -1 ;
+        get_lua_number("texconfig", "start_time", &starttime);
+        if (starttime < 0) {
+            /*
+                We provide this one for compatibility reasons and therefore also in
+                uppercase.
+            */
+            get_lua_number("texconfig", "SOURCE_DATE_EPOCH", &starttime);
+        }
+        if (starttime >= 0) {
+            set_start_time(starttime);
+        }
+
+        utc = -1 ;
+        get_lua_boolean("texconfig", "use_utc_time", &utc);
+        if (utc >= 0 && utc <= 1) {
+            utc_option = utc;
+        }
+
         fix_dumpname();
     } else {
         if (luainit) {

source/texk/web2c/luatexdir/luatex.c

@@ -148,26 +148,75 @@ void mk_shellcmdlist(char *v)
 /* Called from maininit.  Not static because also called from
    luatexdir/lua/luainit.c.  */
 
+/*
+    In order to avoid all kind of time code in the backend code we use a function.
+    The start time can be overloaded in several ways:
+
+    (1) By setting the environmment variable SOURCE_DATE_EPOCH. This will influence
+    the tex parameters, random seed, pdf timestamp and pdf id that is derived
+    from the time. This variable is consulted when the kpse library is enabled
+    which is analogue to other properties.
+
+    (2) By setting the texconfig.start_time variable (as with other variables
+    we use the internal name there). This has the same effect as (1) and is
+    provided for when kpse is not used to set these variables or when an overloaded
+    is wanted. This is analogue to other properties.
+
+    When an utc time is needed one can provide the flag --utc. This property is
+    independent of this time hackery. This flag has a corresponding texconfig
+    option use_utc_time.
+
+    To some extend a cleaner solution would be to have a flag that disables all
+    variable data in one go (like filenames and so) but we just follow the method
+    implemented in pdftex where primitives are used tod disable it.
+
+*/
+
 static int start_time = -1;
 
 int get_start_time(void) {
     if (start_time < 0) {
-        char *source_date_epoch;
+        start_time = time((time_t *) NULL);
+    }
+    return start_time;
+}
+
+/*
+    This one is called as part of the kpse initialization which only happens
+    when this library is enabled.
+*/
+
+void init_start_time(void) {
+    if (start_time < 0) {
         unsigned long long epoch;
         char *endptr;
-        source_date_epoch = getenv("SOURCE_DATE_EPOCH");
-        if (source_date_epoch) {
+        /*
+            We don't really care how kpse sets up this variable but we prefer to
+            just use its abstract interface.
+        */
+     /* char *source_date_epoch = getenv("SOURCE_DATE_EPOCH"); */
+        char *source_date_epoch = kpse_var_value("SOURCE_DATE_EPOCH");
+        if (source_date_epoch && source_date_epoch != '\0' ) {
             errno = 0;
             epoch = strtoull(source_date_epoch, &endptr, 10);
             if (epoch < 0 || *endptr != '\0' || errno != 0) {
                 start_time = 0;
             }
             start_time = epoch;
-        } else {
-            start_time = time((time_t *) NULL);
         }
     }
-    return start_time;
+}
+
+/*
+    This one is used to fetch a value from texconfig which can also be used to
+    set properties. This might come in handy when one has other ways to get date
+    info in the pdf file.
+*/
+
+void set_start_time(int s) {
+    if (s >= 0) {
+        start_time = s ;
+    }
 }
 
 void init_shell_escape(void)

source/texk/web2c/luatexdir/luatex.h

@@ -71,7 +71,9 @@
 /* Executing shell commands.  */
 extern void mk_shellcmdlist(char *);
 extern void init_shell_escape(void);
+extern void init_start_time(void);
 extern int get_start_time(void);
+extern void set_start_time(int);
 extern boolean get_start_time(void);
 
 extern int shell_cmd_is_allowed(const char *cmd, char **safecmd,