# DP: Allow embedded timestamps by C/C++ macros to be set externally gcc/c-family/ChangeLog: 2016-04-27 Eduard Sanou Matthias Klose * c-common.c (get_source_date_epoch): New function, gets the environment variable SOURCE_DATE_EPOCH and parses it as long long with error handling. * c-common.h (get_source_date_epoch): Prototype. * c-lex.c (c_lex_with_flags): set parse_in->source_date_epoch. gcc/ChangeLog: 2016-04-27 Eduard Sanou Matthias Klose * doc/cppenv.texi: Document SOURCE_DATE_EPOCH environment variable. libcpp/ChangeLog: 2016-04-27 Eduard Sanou Matthias Klose * include/cpplib.h (cpp_init_source_date_epoch): Prototype. * init.c (cpp_init_source_date_epoch): New function. * internal.h: Added source_date_epoch variable to struct cpp_reader to store a reproducible date. * macro.c (_cpp_builtin_macro_text): Set pfile->date timestamp from pfile->source_date_epoch instead of localtime if source_date_epoch is set, to be used for __DATE__ and __TIME__ macros to help reproducible builds. Index: b/src/gcc/c-family/c-common.c =================================================================== --- a/src/gcc/c-family/c-common.c +++ b/src/gcc/c-family/c-common.c @@ -12743,4 +12743,37 @@ valid_array_size_p (location_t loc, tree return true; } +/* Read SOURCE_DATE_EPOCH from environment to have a deterministic + timestamp to replace embedded current dates to get reproducible + results. Returns -1 if SOURCE_DATE_EPOCH is not defined. */ +time_t +get_source_date_epoch () +{ + char *source_date_epoch; + long long epoch; + char *endptr; + + source_date_epoch = getenv ("SOURCE_DATE_EPOCH"); + if (!source_date_epoch) + return (time_t) -1; + + errno = 0; + epoch = strtoll (source_date_epoch, &endptr, 10); + if ((errno == ERANGE && (epoch == LLONG_MAX || epoch == LLONG_MIN)) + || (errno != 0 && epoch == 0)) + fatal_error (UNKNOWN_LOCATION, "environment variable $SOURCE_DATE_EPOCH: " + "strtoll: %s\n", xstrerror(errno)); + if (endptr == source_date_epoch) + fatal_error (UNKNOWN_LOCATION, "environment variable $SOURCE_DATE_EPOCH: " + "no digits were found: %s\n", endptr); + if (*endptr != '\0') + fatal_error (UNKNOWN_LOCATION, "environment variable $SOURCE_DATE_EPOCH: " + "trailing garbage: %s\n", endptr); + if (epoch < 0) + fatal_error (UNKNOWN_LOCATION, "environment variable $SOURCE_DATE_EPOCH: " + "value must be nonnegative: %lld \n", epoch); + + return (time_t) epoch; +} + #include "gt-c-family-c-common.h" Index: b/src/gcc/c-family/c-common.h =================================================================== --- a/src/gcc/c-family/c-common.h +++ b/src/gcc/c-family/c-common.h @@ -1467,4 +1467,9 @@ extern bool reject_gcc_builtin (const_tr extern void warn_duplicated_cond_add_or_warn (location_t, tree, vec **); extern bool valid_array_size_p (location_t, tree, tree); +/* Read SOURCE_DATE_EPOCH from environment to have a deterministic + timestamp to replace embedded current dates to get reproducible + results. Returns -1 if SOURCE_DATE_EPOCH is not defined. */ +extern time_t get_source_date_epoch (void); + #endif /* ! GCC_C_COMMON_H */ Index: b/src/gcc/c-family/c-lex.c =================================================================== --- a/src/gcc/c-family/c-lex.c +++ b/src/gcc/c-family/c-lex.c @@ -385,6 +385,9 @@ c_lex_with_flags (tree *value, location_ enum cpp_ttype type; unsigned char add_flags = 0; enum overflow_type overflow = OT_NONE; + time_t source_date_epoch = get_source_date_epoch (); + + cpp_init_source_date_epoch (parse_in, source_date_epoch); timevar_push (TV_CPP); retry: Index: b/src/libcpp/include/cpplib.h =================================================================== --- a/src/libcpp/include/cpplib.h +++ b/src/libcpp/include/cpplib.h @@ -784,6 +784,9 @@ extern void cpp_init_special_builtins (c /* Set up built-ins like __FILE__. */ extern void cpp_init_builtins (cpp_reader *, int); +/* Initialize the source_date_epoch value. */ +extern void cpp_init_source_date_epoch (cpp_reader *, time_t); + /* This is called after options have been parsed, and partially processed. */ extern void cpp_post_options (cpp_reader *); Index: b/src/libcpp/init.c =================================================================== --- a/src/libcpp/init.c +++ b/src/libcpp/init.c @@ -533,8 +533,15 @@ cpp_init_builtins (cpp_reader *pfile, in _cpp_define_builtin (pfile, "__OBJC__ 1"); } +/* Initialize the source_date_epoch value. */ +void +cpp_init_source_date_epoch (cpp_reader *pfile, time_t source_date_epoch) +{ + pfile->source_date_epoch = source_date_epoch; +} + /* Sanity-checks are dependent on command-line options, so it is - called as a subroutine of cpp_read_main_file (). */ + called as a subroutine of cpp_read_main_file. */ #if CHECKING_P static void sanity_checks (cpp_reader *); static void sanity_checks (cpp_reader *pfile) Index: b/src/libcpp/internal.h =================================================================== --- a/src/libcpp/internal.h +++ b/src/libcpp/internal.h @@ -502,6 +502,10 @@ struct cpp_reader const unsigned char *date; const unsigned char *time; + /* Externally set timestamp to replace current date and time useful for + reproducibility. */ + time_t source_date_epoch; + /* EOF token, and a token forcing paste avoidance. */ cpp_token avoid_paste; cpp_token eof; Index: b/src/libcpp/macro.c =================================================================== --- a/src/libcpp/macro.c +++ b/src/libcpp/macro.c @@ -357,13 +357,20 @@ _cpp_builtin_macro_text (cpp_reader *pfi time_t tt; struct tm *tb = NULL; - /* (time_t) -1 is a legitimate value for "number of seconds - since the Epoch", so we have to do a little dance to - distinguish that from a genuine error. */ - errno = 0; - tt = time(NULL); - if (tt != (time_t)-1 || errno == 0) - tb = localtime (&tt); + /* Set a reproducible timestamp for __DATE__ and __TIME__ macro + usage if SOURCE_DATE_EPOCH is defined. */ + if (pfile->source_date_epoch != (time_t) -1) + tb = gmtime (&pfile->source_date_epoch); + else + { + /* (time_t) -1 is a legitimate value for "number of seconds + since the Epoch", so we have to do a little dance to + distinguish that from a genuine error. */ + errno = 0; + tt = time (NULL); + if (tt != (time_t)-1 || errno == 0) + tb = localtime (&tt); + } if (tb) {