utils-std

touch.c (6048B)

// utils-std: Collection of commonly available Unix tools
// SPDX-FileCopyrightText: 2017 Haelwenn (lanodan) Monnier <contact+utils@hacktivis.me>
// SPDX-License-Identifier: MPL-2.0
#define _DEFAULT_SOURCE         // tm_gmtoff/tm_zone
#define _XOPEN_SOURCE 700       // strptime (NetBSD)
#define _POSIX_C_SOURCE 200809L // O_NOFOLLOW, st_atim/st_mtim
#include "../lib/bitmasks.h"  /* FIELD_* */
#include "../lib/iso_parse.h" /* iso_parse */
#include <assert.h>
#include <errno.h>    /* errno */
#include <fcntl.h>    /* open */
#include <stdbool.h>  /* bool */
#include <stdio.h>    /* perror */
#include <stdlib.h>   /* exit, EXIT_FAILURE */
#include <string.h>   /* strrchr, strlen */
#include <sys/stat.h> /* futimens, stat, utimensat */
#include <time.h>     /* mktime */
#include <unistd.h>   /* getopt, opt*, close */
// [[CC]YY]MMDDhhmm[.SS]
static struct timespec
opt_t_parse(char *arg, const char **errstr)
{
	struct timespec res = {.tv_sec = 0, .tv_nsec = 0};
	struct tm tm = {
	    .tm_year = 0,
	    .tm_mon = 0,
	    .tm_mday = 0,
	    .tm_hour = 0,
	    .tm_min = 0,
	    .tm_sec = 0,
	    .tm_isdst = -1, // unknown if DST is in effect
	};
	size_t len = strlen(arg);
	char *secs = strrchr(arg, '.');
	if(secs != NULL)
	{
		if(arg[len - 3] != '.')
		{
			*errstr = "Wrong location of second separator";
			return res;
		}
		secs[0] = 0;
		secs++;
		len -= 3;
		char *s = strptime(secs, "%S", &tm);
		if(s == NULL)
		{
			*errstr = strerror(errno);
			errno = 0;
			return res;
		}
		if(s[0] != 0)
		{
			*errstr = "Extraneous character in seconds";
			return res;
		}
	}
	const char *fmt = NULL;
	switch(len)
	{
	case 8:
		fmt = "%m%d%H%M"; // MMDDhhmm
		break;
	case 10:
		fmt = "%y%m%d%H%M"; // YYMMDDhhmm
		break;
	case 12:
		fmt = "%Y%m%d%H%M"; // CCYYMMDDhhmm
		break;
	default:
		*errstr = "Invalid datetime";
		return res;
	}
	assert(fmt != NULL);
	char *dt = strptime(arg, fmt, &tm);
	if(dt == NULL)
	{
		*errstr = strerror(errno);
		errno = 0;
		return res;
	}
	if(dt[0] != 0)
	{
		*errstr = "Extraneous character in datetime";
		return res;
	}
	res.tv_sec = mktime(&tm);
	if(res.tv_sec == (time_t)-1)
	{
		*errstr = strerror(errno);
		errno = 0;
		return res;
	}
	// As observed on FreeBSD 14.0, non-errorneous mktime can still end up setting errno
	// cf. https://builds.sr.ht/~lanodan/job/1181509
	errno = 0;
	return res;
}
int
main(int argc, char *argv[])
{
	bool ch_atime = false, ch_mtime = false;
	char *ref_file = NULL;
	struct timespec times[2] = {
	    {.tv_sec = 0, .tv_nsec = UTIME_OMIT}, // access
	    {.tv_sec = 0, .tv_nsec = UTIME_OMIT}  // modification
	};
	struct timespec target = {0, UTIME_NOW};
	int open_flags = O_WRONLY | O_CREAT | O_NOCTTY;
	int utimensat_flags = 0;
	int c = 0;
	while((c = getopt(argc, argv, ":achmr:t:d:")) != -1)
	{
		const char *errstr = NULL;
		switch(c)
		{
		case 'a':
			ch_atime = true;
			break;
		case 'c':
			FIELD_CLR(open_flags, O_CREAT);
			break;
		case 'h':
			FIELD_SET(open_flags, O_NOFOLLOW);
			FIELD_SET(utimensat_flags, AT_SYMLINK_NOFOLLOW);
			break;
		case 'm':
			ch_mtime = true;
			break;
		case 'r':
			ref_file = optarg;
			break;
		case 't':
			target = opt_t_parse(optarg, &errstr);
			if(errstr != NULL)
			{
				fprintf(stderr, "touch: error: opt_t_parse(\"%s\", …): %s\n", optarg, errstr);
				exit(EXIT_FAILURE);
			}
			break;
		case 'd':
		{
			long nsec = 0;
			struct tm iso_res = {
			    .tm_year = 0,
			    .tm_mon = 0,
			    .tm_mday = 0,
			    .tm_hour = 0,
			    .tm_min = 0,
			    .tm_sec = 0,
			    .tm_isdst = -1, // unknown if DST is in effect
			    .tm_gmtoff = 0,
			    .tm_zone = NULL,
			};
			char *s = iso_parse(optarg, &iso_res, &nsec, &errstr);
			if(errstr != NULL)
			{
				fprintf(stderr, "touch: error: iso_parse(\"%s\", …): %s\n", optarg, errstr);
				exit(EXIT_FAILURE);
			}
			if(s == NULL)
			{
				fprintf(stderr, "touch: error: iso_parse(\"%s\", …) returned NULL\n", optarg);
				exit(EXIT_FAILURE);
			}
			target.tv_sec = mktime_tz(&iso_res);
			target.tv_nsec = nsec;
			if(target.tv_sec == (time_t)-1)
			{
				fprintf(stderr, "touch: error: mktime: %s\n", strerror(errno));
				exit(EXIT_FAILURE);
			}
			errno = 0;
			break;
		}
		case ':':
			fprintf(stderr, "touch: error: Missing operand for option: '-%c'\n", optopt);
			return 1;
		case '?':
			fprintf(stderr, "touch: error: Unrecognised option: '-%c'\n", optopt);
			return 1;
		}
	}
	argc -= optind;
	argv += optind;
	// When neither -a nor -m are specified, change both
	if(!ch_atime && !ch_mtime)
	{
		ch_atime = true;
		ch_mtime = true;
	}
	if(ref_file == NULL)
	{
		if(ch_atime) times[0] = target;
		if(ch_mtime) times[1] = target;
	}
	else
	{
		struct stat ref;
		if(stat(ref_file, &ref) != 0)
		{
			fprintf(stderr,
			        "touch: error: Failed getting status of file '%s': %s\n",
			        ref_file,
			        strerror(errno));
			return 1;
		}
		if(ch_atime)
		{
			times[0] = ref.st_atim;
		}
		if(ch_mtime)
		{
			times[1] = ref.st_mtim;
		}
	}
	for(int i = 0; i < argc; i++)
	{
		const char *file = argv[i];
		assert(errno == 0);
		int fd = open(file, open_flags, S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP | S_IROTH | S_IWOTH);
		if(fd == -1)
		{
			if(errno == EISDIR)
			{
				if(utimensat(AT_FDCWD, file, times, utimensat_flags) != 0)
				{
					fprintf(stderr,
					        "touch: error: Failed setting new times on directory '%s': %s\n",
					        file,
					        strerror(errno));
					return 1;
				}
				return 0;
			}
			if(errno != ENOENT || FIELD_MATCH(open_flags, O_CREAT))
				fprintf(stderr, "touch: error: Failed opening file '%s': %s\n", file, strerror(errno));
			return 1;
		}
		if(futimens(fd, times) != 0)
		{
			fprintf(stderr,
			        "touch: error: Failed setting new times on file '%s': %s\n",
			        file,
			        strerror(errno));
			return 1;
		}
		if(close(fd) != 0)
		{
			fprintf(stderr,
			        "touch: error: Failed closing file-descriptor for file '%s': %s\n",
			        file,
			        strerror(errno));
			return 1;
		}
	}
	return 0;
}