/*---------------------------------------------------------------------------

   fdate.c                                                    Greg Roelofs

   This program prints the modification time for a file in "YYYYMMDDhhmmss"
   or "YYYYMMDDhhmm.ss" (touch(1)) or Unix (seconds since 1970) format, with
   options to print the access time, status-change time or system time (clock)
   instead.

   To compile:  cc -O -o fdate fdate.c
           or:  gcc -Wall -O -o fdate fdate.c

   Revision History:
     1.00   15 Mar 1993   created
     1.10   15 Apr 1993   added -s option for system date
     1.20    9 Feb 1999   modified default output format for Y2K
     1.30    2 Jan 2000   added -t option for touch(1) output format
     1.31   24 Jan 2000   merged missing 1.20 changes; updated comments
     1.40   23 Sep 2002   added macro(s) for large file support
     1.41   23 Sep 2004   fixed some compiler warnings
     1.50   23 Jan 2005   added support for new-style touch(1) output
     1.60   29 Aug 2005   added -C option to convert Unix integer timestamp

  ---------------------------------------------------------------------------*/

/* GRR 20020923:  see http://www.suse.de/~aj/linux_lfs.html for details */
#define _FILE_OFFSET_BITS  64		/* required */
/* #define _LARGEFILE_SOURCE */		/* not required for stat() */

#include <stdio.h>
#include <stdlib.h>
#include <sys/types.h>	/* time_t, dev_t, etc. */
//#include <sys/time.h>	/* gmtime(), localtime(), strftime(), <time.h> */
#include <time.h>	/* gmtime(), localtime(), strftime(), <time.h> */
#include <sys/stat.h>	/* stat(), struct stat */

#define VERSION  "1.60 of 29 August 2005 (Y2K, large file support)"

/* could change this to enum block... */
#define MODIFICATION   0
#define ACCESS         1
#define STATUS         2
#define SYSTEM         3
#define CONVERT        4


int main(argc, argv)
    int     argc;
    char    *argv[];
{
    char    ascnumtime[32], *outfmt;
    int     c, error=0, lflag=0, gflag=0, tflag=0, Tflag=0, uflag=0;
    int     timetype=MODIFICATION;
    time_t  numtime;


/*---------------------------------------------------------------------------
    Parse command line for '-' options.
  ---------------------------------------------------------------------------*/

    outfmt = "%Y%m%d%H%M%S";   /* default:  monotonic, integer format */

    if (argc <= 1)
        --argc;
    else
        while (--argc > 0  &&  (*++argv)[0] == '-')
            while ((c = *++(argv[0])))  /* argv[0] not program name any more */
                switch (c) {
                    case 'a':
                        timetype = ACCESS;
                        break;
                    case 'c':
                        timetype = STATUS;
                        break;
                    case 'C':
                        timetype = CONVERT;
                        break;
                    case 'g':
                        ++gflag;
                        break;
                    case 'l':
                        ++lflag;
                        break;
                    case 's':
                        timetype = SYSTEM;
                        break;
                    case 't':
                        ++tflag;
                        outfmt = "%Y%m%d%H%M.%S";   /* new-style touch(1) */
                        break;
                    case 'T':
                        ++Tflag;
                        outfmt = "%m%d%H%M%Y.%S";   /* old-style touch(1) */
                        break;
                    case 'u':
                        ++uflag;
                        break;
                    default:
                        ++error;
                        break;
                } /* end switch, while, while, if */

/*---------------------------------------------------------------------------
    Print usage and exit if any errors encountered.
  ---------------------------------------------------------------------------*/

    if (error || ((argc == 0) && (timetype != SYSTEM))) {
        fprintf(stderr, "\
fdate %s, by Greg Roelofs.\n\n\
Print file date(s) or system date in YYYYMMDDhhmmss (default), YYYYMMDDhhmm.ss,\n\
MMDDhhmmYYYY.ss, or Unix integer format.\n\n\
usage:  fdate [ -acgltu ] file [ file ... ]\n\
        fdate -s [ -gtu ]\n\
        fdate -C [ -gt ] unixtime\n\
  -a  print time of last access\n\
  -c  print time of last status change\n\
  -C  convert Unix integer format to human-readable form\n\
  -g  use GMT (UTC) instead of local time for non-Unix output formats\n\
  -l  long format:  print filename(s) as well\n\
  -s  print system time\n\
  -t  use new-style \"touch\" output format (YYYYMMDDhhmm.ss)\n\
  -T  use old-style \"touch\" output format (MMDDhhmmYYYY.ss)\n\
  -u  use Unix integer time format (always GMT/UTC)\n", VERSION);
        exit(1);
    }

/*---------------------------------------------------------------------------
    Get and print system time.
  ---------------------------------------------------------------------------*/

    if (timetype == SYSTEM || timetype == CONVERT) {
        if (lflag) {
            fprintf(stderr, "fdate:  -l option ignored with -%c\n",
              (timetype == SYSTEM)? 's' : 'C');
            lflag = 0;
            ++error;
        }

        if (timetype == SYSTEM)
            numtime = time((time_t *)NULL);
        else
            numtime = atol(argv[0]);

        if (uflag)
            sprintf(ascnumtime, "%lu", (unsigned long)numtime); 
        else {
            strftime(ascnumtime, 32, outfmt,
              gflag? gmtime(&numtime) : localtime(&numtime));
        }
        printf("%s\n", ascnumtime);

        return error? 1 : 0;
    }

/*---------------------------------------------------------------------------
    Loop through files on command line, printing timestamps for each.
  ---------------------------------------------------------------------------*/

    while (argc-- > 0) {
        struct stat  statbuf;

        if (stat(*argv, &statbuf)) {
            fprintf(stderr, "fdate:  file not found: %s\n", *argv++);
	    ++error;
            continue;
        }
        switch (timetype) {
            case ACCESS:
                numtime = statbuf.st_atime;
                break;
            case STATUS:
                numtime = statbuf.st_ctime;
                break;
            default:
                numtime = statbuf.st_mtime;
                break;
        }
        /* convert time to string, one way or other */
        if (uflag)
            sprintf(ascnumtime, "%lu", (unsigned long)numtime); 
        else {
            strftime(ascnumtime, 32, outfmt,
              gflag? gmtime(&numtime) : localtime(&numtime));
        }
        /* FIXME: do we want to include "touch -t"/"touch" for -t/-T, resp.? */
        printf("%s  %s\n", ascnumtime, lflag? *argv : "");

        ++argv;
    }

    return error? 1 : 0;

} /* end main() */