/* Posix time support for scsh. ** Copyright (c) 1994 by Olin Shivers. */ /* The source code is conditionalised by three #ifdef feature macros: ** HAVE_STRUCT_TM_TM_ZONE/HAVE_TZNAME ** The char *tzname[2] global variable is POSIX. Everyone provides ** it...except some "classic" versions of SunOS that we still care about ** running (People in LCS/AI refuse to switch to Solaris). So, we kluge ** around not having it. ** ** HAVE_GMTOFF ** Some systems (NetBSD, NeXTSTEP, Solaris) have a non-standard field in the ** tm struct, the tm_gmtoff field. localtime() sets it to the offset from ** UTC for the current time. If you have this field, it is trivial to ** compute the the UTC time zone offset. If you have a strict POSIX system, ** and don't have it, then the offset can be computed with a slower ** technique. ** ** NeXT ** The presence of this feature macro means that, basically, you are ** screwed, and should go download yourself a real Unix system off the ** Net. For free. ** ** More specifically, it means that (1) the presence of the strftime() ** function will cause the whole system build to die at link time, ** when compiled with the -posix flag. (NeXT bug #59098) There is no fix ** for this as of November 1994. Thanks, guys. ** ** We handle this problem by abandoning ship. When compiled under NeXT, ** your time zone is always computed to be the empty string. ** ** The other problem is that (2) NeXT's mktime() procedure pays attention ** to the gmt_offset field of the tm struct you give it, instead of ** the $TZ environment variable. So there is no way to convert a date ** to a time without knowing in advance what the UTC offset is in seconds. ** This screws up scsh's DATE->TIME procedure. */ #include #include #include #include #include "sysdep.h" #include "cstuff.h" #include "time1.h" /* Make sure the .h interface agrees with the code. */ #include /* JMG debug */ extern char **environ; /* To work in the UTC time zone, do "environ = utc_env;". */ static char *utc_env[] = {"TZ=UCT0", 0}; #if defined(HAVE_TZNAME) && !defined(CYGWIN) extern char *tzname[]; /* Why isn't this defined in time.h? */ #endif /* These two functions allow you to temporarily override ** the current time zone with one of your choice. make_newenv() ** takes a time zone string as an argument, and constructs a Unix environ ** vector with a single entry: "TZ=". You pass the new environ vector ** as an argument. It installs the new environment, and returns the old ** one. You can later pass the old environment back to revert_env() ** to reinstall the old environment and free up malloc'd storage. ** ** On error, make_newenv returns NULL. */ static char **make_newenv(s48_value zone, char *newenv[2]) { int zonelen = S48_STRING_LENGTH(zone); char **oldenv = environ, *tz = Malloc(char, 4+zonelen); char * extracted_zone = s48_extract_string(zone); /* s48_value temp; */ if( !tz ) return NULL; strcpy(tz, "TZ="); /* temp = S48_STRING_REF(zone,0);*/ /* JMG */ /* strncpy(tz+3, &temp, zonelen);*/ strncpy(tz+3, extracted_zone, zonelen); tz[zonelen+3] = '\0'; newenv[0] = tz; newenv[1] = NULL; environ = newenv; /* Install it. */ return oldenv; } static void revert_env(char **old_env) { char *tz = *environ; environ = old_env; Free(tz); } /*****************************************************************************/ s48_value scheme_time() { time_t t; errno = 0; t = time(NULL); if( t == -1 && errno ) s48_raise_os_error (errno); return s48_enter_integer (t); } /* Zone: ** #f Local time ** int Offset from GMT in seconds. ** string Time zone understood by OS. */ s48_value time2date(s48_value sch_t, s48_value sch_zone) /* int *sec, int *min, int *hour, int *mday, int *month, int *year, const char **tz_name, int *tz_secs, int *summer, int *wday, int *yday) */ { struct tm d; time_t t = s48_extract_integer(sch_t); s48_value sch_tz_name = S48_UNSPECIFIC; s48_value sch_tz_secs = S48_UNSPECIFIC; if( S48_FIXNUM_P(sch_zone) ) { /* Offset from GMT in secs. */ int offset = s48_extract_fixnum(sch_zone); t += s48_extract_fixnum(sch_zone); d = *gmtime(&t); sch_tz_name = S48_FALSE; sch_tz_secs = s48_enter_fixnum (offset); } else { char *newenv[2], **oldenv = NULL; if( S48_STRING_P(sch_zone) ) { /* Time zone */ oldenv = make_newenv(sch_zone, newenv); /* Install new TZ. */ if( !oldenv ) s48_raise_os_error_2(errno, sch_t, sch_zone); d = *localtime(&t); /* Do it. */ } else /* Local time */ d = *localtime(&t); /* This little chunk of code copies the calculated time zone into ** a malloc'd buffer and assigns it to *tz_name. It's a little ** complicated because we have to clean up after detecting an ** error w/o walking on errno. ** ** The time zone has to be stashed into a malloc'd buffer because ** when revert_env resets to the original time zone, it will ** overwrite the static buffer tzname. We have to copy it out before ** that happens. */ { int error = 0; #ifdef HAVE_TZNAME char *zone = tzname[d.tm_isdst]; #else #ifdef HAVE_STRUCT_TM_TM_ZONE const char *zone = d.tm_zone; /* Hack it for SunOS. */ #endif #endif char *newzone = Malloc(char, 1+strlen(zone)); if( newzone ){ strcpy(newzone, zone); sch_tz_name = s48_enter_string (newzone); } else error = errno; if( oldenv ) revert_env(oldenv); /* Revert TZ & env. */ if( !newzone ) s48_raise_os_error_2(error, sch_t, sch_zone); } /* Calculate the time-zone offset in seconds from UTC. */ #ifdef HAVE_GMTOFF sch_tz_secs = s48_enter_fixnum (d.tm_gmtoff); #else { char **oldenv = environ; /* Set TZ to UTC */ environ=utc_env; /* time temporarily. */ tzset(); /* NetBSD, SunOS POSIX-noncompliance requires this. */ sch_tz_secs = s48_enter_fixnum (mktime(&d) - t); environ=oldenv; } #endif } return s48_list_11 (s48_enter_fixnum (d.tm_sec), s48_enter_fixnum (d.tm_min), s48_enter_fixnum (d.tm_hour), s48_enter_fixnum (d.tm_mday), s48_enter_fixnum (d.tm_mon), s48_enter_fixnum (d.tm_year), sch_tz_name, sch_tz_secs, d.tm_isdst ? S48_TRUE : S48_FALSE, s48_enter_fixnum (d.tm_wday), s48_enter_fixnum (d.tm_yday)); } /* Oops ** There's a fundamental problem with the Posix mktime() function used below ** -- it's error return value (-1) is also a valid return value, for date ** 11:59:00 UTC, 12/31/1969 ** ** 1. We choose to err on the paranoid side. If mktime() returns -1, it is ** considered an error. ** 2. If we return an error, we try to return a useful errno value, if we can. ** ** Who designed this interface? */ s48_value date2time(s48_value sec, s48_value min, s48_value hour, s48_value mday, s48_value month, s48_value year, s48_value tz_name, s48_value tz_secs, s48_value summer) { time_t t; struct tm d; int err = 0; d.tm_sec = s48_extract_fixnum (sec); d.tm_min = s48_extract_fixnum (min); d.tm_hour = s48_extract_fixnum (hour); d.tm_mday = s48_extract_fixnum (mday); d.tm_mon = s48_extract_fixnum (month); d.tm_year = s48_extract_fixnum (year); d.tm_wday = 0; d.tm_yday = 0; if( S48_FIXNUM_P(tz_secs) ) { /* Offset from GMT in seconds. */ char **oldenv = environ; /* Set TZ to UTC */ environ = utc_env; /* time temporarily. */ tzset(); /* NetBSD, SunOS POSIX-noncompliance requires this. */ d.tm_isdst = 0; /* FreeBSD, at least, needs this or it sulks. */ t = mktime(&d); if (t == -1) err = 1; t -= s48_extract_fixnum(tz_secs); environ = oldenv; } /* ### Note that we *still* don't implement the manual paragraph with "When calcultating with time-zones, the date's SUMMER? field is used to resolve ambiguities. */ else if( S48_STRING_P(tz_name) ) { /* Time zone */ char *newenv[2]; char **oldenv = make_newenv(tz_name, newenv); if( !oldenv ) return s48_enter_fixnum(errno); tzset(); /* NetBSD, SunOS POSIX-noncompliance requires this. */ errno = 0; d.tm_isdst = -1; t = mktime(&d); if (t == -1) err = 1; revert_env(oldenv); } else { /* Local time */ tzset(); /* NetBSD, SunOS POSIX-noncompliance requires this. */ errno = 0; d.tm_isdst = -1; t = mktime(&d); if (t == -1) err = 1; } return s48_cons (err ? S48_TRUE : S48_FALSE, s48_enter_integer(t)); } /* WARNING WARNING WARNING WARNING WARNING WARNING WARNING WARNING ** ** This code doesn't work under NeXTSTEP. I have cleverly #included the ** critical call to strftime() out for NeXT. This is because the compiler ** blows up on Posix compiles involving strftime(). Go figure. */ /* It's disgusting how long and tortuous this function is, just ** to interface to the strftime() function. -Olin ** ** There's a weird screw case this code is careful to handle. Exhibiting ** classic Unix design (we use the term loosely), strftime()'s error ** return (0) is also a legal return value for some boundary cases. ** For example, if the format string is empty, or it is "%Z" and ** the time-zone is not available, then the result string is 0 chars long. ** We distinguish this case by suffixing an "x" to the format string, ** and flushing the last char in the formatted result. ** ** Don't consider *prefixing* an "x" instead, because then you'd ** probably pass back &result[1] to skip the x, and that would lose -- ** the guy we are handing the string to will later pass it to free(), ** so we can't pass back a pointer to anything other than the very front ** of the block. ** ** Professional programmers sacrifice their pride that others may live. ** Why me? Why Unix? */ s48_value format_date(s48_value sch_fmt, s48_value sch_sec, s48_value sch_min, s48_value sch_hour, s48_value sch_mday, s48_value sch_month, s48_value sch_year, s48_value sch_tz, s48_value sch_summer, s48_value sch_week_day, s48_value sch_year_day) { struct tm d; char *fmt = s48_extract_string(sch_fmt); int fmt_len = strlen(fmt); char *fmt2 = Malloc(char, 2+2*fmt_len); /* 1 extra for prefixed "x" char.*/ int target_len = 1; /* 1 for the prefixed "x" char. Ugh. */ int zone = 0; /* Are we using the time-zone? */ char *q, *target; const char *p; char *newenv[2], **oldenv = NULL; int result_len; s48_value sch_ans = S48_UNSPECIFIC; if( !fmt2 ) s48_raise_os_error_1(errno, sch_fmt); d.tm_sec = s48_extract_fixnum(sch_sec); d.tm_min = s48_extract_fixnum(sch_min); d.tm_hour = s48_extract_fixnum(sch_hour); d.tm_mday = s48_extract_fixnum(sch_mday); d.tm_mon = s48_extract_fixnum(sch_month); d.tm_year = s48_extract_fixnum(sch_year); d.tm_wday = s48_extract_fixnum(sch_week_day); d.tm_yday = s48_extract_fixnum(sch_year_day); d.tm_isdst = (S48_EQ_P (sch_summer, S48_FALSE)) ? 0 : 1; #ifdef HAVE_STRUCT_TM_TM_ZONE d.tm_zone = s48_extract_string(sch_tz); /* FreeBSD's strftime reads this */ #endif /* Copy fmt -> fmt2, converting ~ escape codes to % escape codes. ** Set zone=1 if fmt has a ~Z. ** Build up an estimate of how large the target buffer needs to be. ** The length calculation is not required to be accurate. */ for(q=fmt2, p=fmt; *p; p++) { if( *p != '~' ) { target_len++; *q++ = *p; if( *p == '%' ) *q++ = '%'; /* Percents get doubled. */ } else { char c = *++p; if( ! c ) { Free(fmt2); return S48_FALSE; /* % has to be followed by something. */ } else if( c == '~' ) { *q++ = '~'; target_len++; } else { *q++ = '%'; *q++ = c; switch (c) { case 'a': target_len += 3; break; case 'A': target_len += 9; break; case 'b': target_len += 3; break; case 'B': target_len += 9; break; case 'c': target_len += 10; break; /* wtf */ case 'd': target_len += 2; break; case 'H': target_len += 2; break; case 'I': target_len += 2; break; case 'j': target_len += 3; break; case 'm': target_len += 2; break; case 'M': target_len += 2; break; case 'p': target_len += 2; break; case 'S': target_len += 2; break; case 'U': target_len += 2; break; case 'w': target_len += 1; break; case 'W': target_len += 2; break; case 'x': target_len += 10; break; /* wtf */ case 'X': target_len += 10; break; /* wtf */ case 'y': target_len += 2; break; case 'Y': target_len += 4; break; case 'Z': target_len += 6; zone++; break; default: target_len += 5; break; /* wtf */ } } } } *q++ = 'x'; *q = '\0'; /* Append the guard "x" suffix and nul-terminate. */ /* Fix up the time-zone if it is being used and the user passed one in. */ if( zone && S48_STRING_P(sch_tz) ) { oldenv = make_newenv(sch_tz, newenv); if( !oldenv ) { int err = errno; Free(fmt); s48_raise_os_error_1(errno, sch_fmt); } } /* Call strftime with increasingly larger buffers until the result fits. */ target = Malloc(char, target_len); if( !target ) goto lose; /* Alloc lost. */ #ifndef NeXT while( !(result_len=strftime(target, target_len, fmt2, &d)) ) { target_len *= 2; target = Realloc(char, target, target_len); if( !target ) goto lose; } target[result_len-1] = '\0'; /* Flush the trailing "x". */ #endif sch_ans = s48_enter_string(target); Free(fmt2); if( oldenv ) revert_env(oldenv); return sch_ans; lose: /* We lost trying to allocate space for the strftime() target buffer. */ {int err = errno; if( oldenv ) revert_env(oldenv); /* Clean up */ Free(fmt2); s48_raise_os_error_1(err, sch_fmt); } } #if 0 /* This is a kludge one can use should the tzname variable ** not be present on the system. Only SunOS is broken this way, ** and it has a non-standard alternative we can use for this application. ** So this code is commented out. ** ** tzname_loser(int dst) returns a string containing the current time zone ** for loser OS's. The string is statically allocated. If the time zone ** is longer than some hidden, arbitrary length, the function simply ** returns the empty string. It is a workaround for tzname[dp->tm_isdst]. ** */ char *tzname_loser(struct tm *dp) { static char buf[1024]; return strftime(buf, 1024, "x%Z", dp) ? buf+1 : ""; } #endif /* clear errno before mktime() and time(), if -1 ret, return errno. ** This is defined to work under HP-UX at least; ** other man pages are silent. ** gettimeofday() returns -1/errno ** localtime() & gmtime() don't error. */ void s48_init_time(void) { S48_EXPORT_FUNCTION(time_plus_ticks); S48_EXPORT_FUNCTION(scheme_time); S48_EXPORT_FUNCTION(date2time); S48_EXPORT_FUNCTION(time2date); S48_EXPORT_FUNCTION(format_date); }