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sbase/touch.c
Michael Forney 3c12b287ec touch: Avoid unnecessary call to stat
Now, we first try a utimensat. If it succeeds, we are done, if not (and no -c
flag), create the file, then set the times with futimens.
2016-07-09 10:17:16 +01:00

160 lines
2.7 KiB
C

/* See LICENSE file for copyright and license details. */
#include <sys/stat.h>
#include <errno.h>
#include <fcntl.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>
#include <unistd.h>
#include "util.h"
static int aflag;
static int cflag;
static int mflag;
static struct timespec times[2] = {{.tv_nsec = UTIME_NOW}};
static void
touch(const char *file)
{
int fd, ret;
if (utimensat(AT_FDCWD, file, times, 0) == 0)
return;
if (errno != ENOENT)
eprintf("utimensat %s:", file);
if (cflag)
return;
if ((fd = open(file, O_WRONLY | O_CREAT | O_EXCL, 0666)) < 0)
eprintf("open %s:", file);
ret = futimens(fd, times);
close(fd);
if (ret < 0)
eprintf("futimens %s:", file);
}
static time_t
parsetime(char *str)
{
time_t now;
struct tm *cur, t = { 0 };
int zulu = 0;
char *format;
size_t len = strlen(str);
if ((now = time(NULL)) == -1)
eprintf("time:");
if (!(cur = localtime(&now)))
eprintf("localtime:");
t.tm_isdst = -1;
switch (len) {
/* -t flag argument */
case 8:
t.tm_year = cur->tm_year;
format = "%m%d%H%M";
break;
case 10:
format = "%y%m%d%H%M";
break;
case 11:
t.tm_year = cur->tm_year;
format = "%m%d%H%M.%S";
break;
case 12:
format = "%Y%m%d%H%M";
break;
case 13:
format = "%y%m%d%H%M.%S";
break;
case 15:
format = "%Y%m%d%H%M.%S";
break;
/* -d flag argument */
case 19:
format = "%Y-%m-%dT%H:%M:%S";
break;
case 20:
/* only Zulu-timezone supported */
if (str[19] != 'Z')
eprintf("Invalid time zone\n");
str[19] = 0;
zulu = 1;
format = "%Y-%m-%dT%H:%M:%S";
break;
default:
eprintf("Invalid date format length\n", str);
}
if (!strptime(str, format, &t))
eprintf("strptime %s: Invalid date format\n", str);
if (zulu) {
t.tm_hour += t.tm_gmtoff / 60;
t.tm_gmtoff = 0;
t.tm_zone = "Z";
}
return mktime(&t);
}
static void
usage(void)
{
eprintf("usage: %s [-acm] [-d time | -r ref_file | -t time | -T time] "
"file ...\n", argv0);
}
int
main(int argc, char *argv[])
{
struct stat st;
char *ref = NULL;
ARGBEGIN {
case 'a':
aflag = 1;
break;
case 'c':
cflag = 1;
break;
case 'd':
case 't':
times[0].tv_sec = parsetime(EARGF(usage()));
times[0].tv_nsec = 0;
break;
case 'm':
mflag = 1;
break;
case 'r':
ref = EARGF(usage());
if (stat(ref, &st) < 0)
eprintf("stat '%s':", ref);
times[0] = st.st_atim;
times[1] = st.st_mtim;
break;
case 'T':
times[0].tv_sec = estrtonum(EARGF(usage()), 0, LLONG_MAX);
times[0].tv_nsec = 0;
break;
default:
usage();
} ARGEND
if (!argc)
usage();
if (!aflag && !mflag)
aflag = mflag = 1;
if (!ref)
times[1] = times[0];
if (!aflag)
times[0].tv_nsec = UTIME_OMIT;
if (!mflag)
times[1].tv_nsec = UTIME_OMIT;
for (; *argv; argc--, argv++)
touch(*argv);
return 0;
}