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      1 /* touch.c : change timestamp of a file
      2  *
      3  * Copyright 2012 Choubey Ji <warior.linux (at) gmail.com>
      4  *
      5  * See http://pubs.opengroup.org/onlinepubs/9699919799/utilities/touch.html
      6 
      7 USE_TOUCH(NEWTOY(touch, "<1acd:mr:t:h[!dtr]", TOYFLAG_BIN))
      8 
      9 config TOUCH
     10   bool "touch"
     11   default y
     12   help
     13     usage: touch [-amch] [-d DATE] [-t TIME] [-r FILE] FILE...
     14 
     15     Update the access and modification times of each FILE to the current time.
     16 
     17     -a	change access time
     18     -m	change modification time
     19     -c	don't create file
     20     -h	change symlink
     21     -d	set time to DATE (in YYYY-MM-DDThh:mm:SS[.frac][tz] format)
     22     -t	set time to TIME (in [[CC]YY]MMDDhhmm[.ss][frac] format)
     23     -r	set time same as reference FILE
     24 */
     25 
     26 #define FOR_touch
     27 #include "toys.h"
     28 
     29 GLOBALS(
     30   char *time;
     31   char *file;
     32   char *date;
     33 )
     34 
     35 void touch_main(void)
     36 {
     37   struct timespec ts[2];
     38   char **ss;
     39   int fd, i;
     40 
     41   // use current time if no -t or -d
     42   ts[0].tv_nsec = UTIME_NOW;
     43   if (toys.optflags & (FLAG_t|FLAG_d)) {
     44     char *s, *date, **format;
     45     struct tm tm;
     46     int len = 0;
     47 
     48     // Initialize default values for time fields
     49     ts->tv_sec = time(0);
     50     ts->tv_nsec = 0;
     51 
     52     // List of search types
     53     if (toys.optflags & FLAG_d) {
     54       format = (char *[]){"%Y-%m-%dT%T", "%Y-%m-%d %T", 0};
     55       date = TT.date;
     56     } else {
     57       format = (char *[]){"%m%d%H%M", "%y%m%d%H%M", "%C%y%m%d%H%M", 0};
     58       date = TT.time;
     59     }
     60 
     61     // Trailing Z means UTC timezone, don't expect libc to know this.
     62     i = strlen(s = date);
     63     if (i && toupper(date[i-1])=='Z') {
     64       date[i-1] = 0;
     65       setenv("TZ", "UTC0", 1);
     66     }
     67 
     68     while (*format) {
     69       if (toys.optflags&FLAG_t) {
     70         s = strchr(date, '.');
     71         if ((s ? s-date : strlen(date)) != strlen(*format)) {
     72           format++;
     73           continue;
     74         }
     75       }
     76       localtime_r(&(ts->tv_sec), &tm);
     77       // Adjusting for daylight savings time gives the wrong answer.
     78       tm.tm_isdst = 0;
     79       tm.tm_sec = 0;
     80       s = strptime(date, *format++, &tm);
     81 
     82       // parse nanoseconds
     83       if (s && *s=='.' && isdigit(s[1])) {
     84         s++;
     85         if (toys.optflags&FLAG_t)
     86           if (1 == sscanf(s, "%2u%n", &(tm.tm_sec), &len)) s += len;
     87         if (1 == sscanf(s, "%lu%n", &ts->tv_nsec, &len)) {
     88           s += len;
     89           if (ts->tv_nsec > 999999999) s = 0;
     90           else while (len++ < 9) ts->tv_nsec *= 10;
     91         }
     92       }
     93       if (s && !*s) break;
     94     }
     95 
     96     errno = 0;
     97     ts->tv_sec = mktime(&tm);
     98     if (!s || *s || ts->tv_sec == -1) perror_exit("bad '%s'", date);
     99   }
    100   ts[1]=ts[0];
    101 
    102   // Set time from -r?
    103 
    104   if (TT.file) {
    105     struct stat st;
    106 
    107     xstat(TT.file, &st);
    108     ts[0] = st.st_atim;
    109     ts[1] = st.st_mtim;
    110   }
    111 
    112   // Which time(s) should we actually change?
    113   i = toys.optflags & (FLAG_a|FLAG_m);
    114   if (i && i!=(FLAG_a|FLAG_m)) ts[i!=FLAG_m].tv_nsec = UTIME_OMIT;
    115 
    116   // Loop through files on command line
    117   for (ss = toys.optargs; *ss;) {
    118     char *s = *ss++;
    119 
    120     if (!strcmp(s, "-")) {
    121       if (!futimens(1, ts)) continue;
    122     } else {
    123       // cheat: FLAG_h is rightmost flag, so its value is 1
    124       if (!utimensat(AT_FDCWD, s, ts,
    125           (toys.optflags & FLAG_h)*AT_SYMLINK_NOFOLLOW)) continue;
    126       if (toys.optflags & FLAG_c) continue;
    127       if (access(s, F_OK) && (-1!=(fd = open(s, O_CREAT, 0666)))) {
    128         close(fd);
    129         if (toys.optflags) ss--;
    130         continue;
    131       }
    132     }
    133     perror_msg("'%s'", s);
    134   }
    135 }
    136