diff options
| -rw-r--r-- | toys/date.c | 103 |
1 files changed, 103 insertions, 0 deletions
diff --git a/toys/date.c b/toys/date.c new file mode 100644 index 00000000..ebcdeb1f --- /dev/null +++ b/toys/date.c @@ -0,0 +1,103 @@ +/* vi: set sw=4 ts=4: + * + * date.c - set/get the date + * + * Copyright 2012 Andre Renaud <andre@bluewatersys.com> + * + * See http://pubs.opengroup.org/onlinepubs/9699919799/utilities/date.html + +USE_DATE(NEWTOY(date, "u", TOYFLAG_BIN)) + +config DATE + bool "date" + default y + help + usage: date [-u] [+format] | mmddhhmm[[cc]yy] + + Set/get the current date/time +*/ + +#include "toys.h" + +/* Convert a string of decimal numbers to their integer equivalent */ +static int fromdec(const char *buf, int len) +{ + int result = 0; + while (len--) + result=result * 10 + (*buf++ - '0'); + return result; +} + +void date_main(void) +{ + const char *format_string = "%a %b %e %H:%M:%S %Z %Y"; + + /* Check if we should be displaying the date */ + if (!toys.optargs[0] || toys.optargs[0][0] == '+') { + time_t now = time(NULL); + struct tm *tm; + if (toys.optargs[0]) + format_string = &toys.optargs[0][1]; + if (toys.optflags) + tm = gmtime(&now); + else + tm = localtime(&now); + if (!tm) + perror_msg("Unable to retrieve current time"); + if (!strftime(toybuf, sizeof(toybuf), format_string, tm)) + perror_msg("invalid format string `%s'", format_string); + puts(toybuf); + } else { + int len = strlen(toys.optargs[0]); + struct tm tm; + struct timeval tv; + + if (len < 8 || len > 12 || len & 1) + error_msg("invalid date `%s'", toys.optargs[0]); + memset(&tm, 0, sizeof(tm)); + /* Date format: mmddhhmm[[cc]yy] */ + tm.tm_mon = fromdec(toys.optargs[0], 2) - 1; + tm.tm_mday = fromdec(&toys.optargs[0][2], 2); + tm.tm_hour = fromdec(&toys.optargs[0][4], 2); + tm.tm_min = fromdec(&toys.optargs[0][6], 2); + if (len == 12) + tm.tm_year = fromdec(&toys.optargs[0][8], 4) - 1900; + else if (len == 10) { + tm.tm_year = fromdec(&toys.optargs[0][8], 2); + /* 69-99 = 1969-1999, 0 - 68 = 2000-2068 */ + if (tm.tm_year < 69) + tm.tm_year += 100; + } else { + /* Year not specified, so retrieve current year */ + time_t now = time(NULL); + struct tm *now_tm = localtime(&now); + if (!now_tm) + perror_msg("Unable to retrieve current time"); + tm.tm_year = now_tm->tm_year; + } + if (!toys.optflags) + tv.tv_sec = mktime(&tm); + else { + /* Get the UTC version of a struct tm */ + char *tz = NULL; + tz = getenv("TZ"); + setenv("TZ", "", 1); + tzset(); + tv.tv_sec = mktime(&tm); + if (tz) + setenv("TZ", tz, 1); + else + unsetenv("TZ"); + tzset(); + } + + if (tv.tv_sec == (time_t)-1) + error_msg("invalid date `%s'", toys.optargs[0]); + tv.tv_usec = 0; + if (!strftime(toybuf, sizeof(toybuf), format_string, &tm)) + perror_msg("invalid format string `%s'", format_string); + puts(toybuf); + if (settimeofday(&tv, NULL) < 0) + perror_msg("cannot set date"); + } +} |