view toys/touch.c @ 194:30a6db5a95c2

Add comments about SUSv3 specs (or lack thereof).
author Rob Landley <rob@landley.net>
date Mon, 03 Dec 2007 20:05:57 -0600
parents 6a12feedd893
children 3227c5316260
line wrap: on
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/* vi: set sw=4 ts=4: */
/*
 * touch.c - Modify a file's timestamps.
 *
 * Copyright (C) 2007 Charlie Shepherd <masterdriverz@gentoo.org>
 *
 * See http://www.opengroup.org/onlinepubs/007904975/utilities/touch.html
 */

#define _XOPEN_SOURCE 600
#include <unistd.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <utime.h>
#include <time.h>
#include "toys.h"

#define OPT_MTIME		0x01
#define OPT_NOCREATE	0x02
#define OPT_ATIME		0x04
#define OPT_REFERENCE	0x08
#define OPT_TIME		0x10
#define OPT_LENGTH		0x20

void touch_main(void)
{
	char *arg;
	int i, set_a, set_m;
	time_t curr_a, curr_m;

	set_a = !!(toys.optflags & OPT_ATIME);
	set_m = !!(toys.optflags & OPT_MTIME);

	// Use timestamp on a file
	if (toys.optflags & OPT_REFERENCE) {
		struct stat sb;

		if (toys.optflags & OPT_TIME)
			error_exit("Redundant time source");
		xstat(toy.touch.ref_file, &sb);
		curr_m = sb.st_mtime;
		curr_a = sb.st_atime;

	// Use time specified on command line.
	} else if (toys.optflags & OPT_TIME) {
		struct tm t;
		time_t curr;
		char *c;

		curr = time(NULL);
		if (localtime_r(&curr, &t)
			|| !(c = strptime(toy.touch.time, "%m%d%H%M", &t))
			|| *c || -1==(curr_a = curr_m = mktime(&t)))
		{
			error_exit("Unknown time %s", toy.touch.time);
		}

	// use current time
	} else curr_m = curr_a = time(NULL);

	for (i = 0; (arg = toys.optargs[i]); i++) {
		struct utimbuf buf;
		struct stat sb;

		buf.modtime = curr_m;
		buf.actime = curr_a;

		if (stat(arg, &sb) == -1) {
			if (!(toys.optflags & OPT_NOCREATE) && errno == ENOENT) {
				if (creat(arg, 0644))
					goto error;
				if (stat(arg, &sb))
					goto error;
			}
		}

		if ((set_a+set_m) == 1) {
			/* We've been asked to only change one */
			if (set_a) buf.modtime = sb.st_mtime;
			else if (set_m) buf.actime = sb.st_atime;
		}

		if (toys.optflags & OPT_LENGTH)
			if (truncate(arg, toy.touch.length))
				goto error;
		if (utime(arg, &buf))
error:
			perror_exit(arg);
	}
}