Add touch(1).

utils/.gitignore

@@ -43,6 +43,7 @@ sort
 stat
 tail
 time
+touch
 tr
 true
 type

utils/Makefile

@@ -55,6 +55,7 @@ sort \
 stat \
 tail \
 time \
+touch \
 tr \
 true \
 type \

utils/touch.cpp

@@ -0,0 +1,171 @@
+/*
+ * Copyright (c) 2015 Alexandros Alexandrou.
+ *
+ * Permission to use, copy, modify, and distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+
+#include <sys/stat.h>
+
+#include <err.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <locale.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <time.h>
+#include <timespec.h>
+#include <unistd.h>
+
+static void compact_arguments(int* argc, char*** argv)
+{
+	for ( int i = 0; i < *argc; i++ )
+	{
+		while ( i < *argc && !(*argv)[i] )
+		{
+			for ( int n = i; n < *argc; n++ )
+				(*argv)[n] = (*argv)[n+1];
+			(*argc)--;
+		}
+	}
+}
+
+static void version(FILE* fp, const char* argv0)
+{
+	fprintf(fp, "%s (Sortix) %s\n", argv0, VERSIONSTR);
+}
+
+static void help(FILE* fp, const char* argv0)
+{
+	fprintf(fp, "Usage: %s [OPTION]... [FILE]\n", argv0);
+	fprintf(fp, "Update access and/or modification time of FILE(s).\n");
+	fprintf(fp, "  -a           Change only access time.\n");
+	fprintf(fp, "  -c           Don't create a specified file if it doesn't exist.\n");
+	fprintf(fp, "  -m           Change only modification time.\n");
+	fprintf(fp, "  -r ref_file  Refer to access and modifiaction times of ref_file.\n");
+}
+
+int main(int argc, char* argv[])
+{
+	setlocale(LC_ALL, "");
+
+	bool opt_a = false;
+	bool opt_c = false;
+	bool opt_m = false;
+	const char* opt_r = NULL;
+
+	const char* argv0 = argv[0];
+	for ( int i = 1; i < argc; i++ )
+	{
+		const char* arg = argv[i];
+		if ( arg[0] != '-' || !arg[1] )
+			continue;
+		argv[i] = NULL;
+		if ( !strcmp(arg, "--") )
+			break;
+		if ( arg[1] != '-' )
+		{
+			char c;
+			while ( (c = *++arg) ) switch (c)
+			{
+			case 'a': opt_a = true; break;
+			case 'c': opt_c = true; break;
+			// TODO: -d
+			case 'm': opt_m = true; break;
+			case 'r':
+				if ( !*(opt_r = arg + 1) )
+				{
+					if ( i + 1 == argc )
+					{
+						fprintf(stderr, "option requires an argument -- 'r'\n");
+						fprintf(stderr, "Try '%s --help' for more information.\n", argv0);
+						exit(125);
+					}
+					opt_r = argv[i+1];
+					argv[++i] = NULL;
+				}
+				arg = "r";
+				break;
+			// TODO: -t
+			default:
+				fprintf(stderr, "%s: unknown option -- '%c'\n", argv0, c);
+				fprintf(stderr, "Try '%s --help' for more information.\n", argv0);
+				exit(1);
+			}
+		}
+		else if ( !strcmp(arg, "--help") )
+			help(stdout, argv0), exit(0);
+		else if ( !strcmp(arg, "--version") )
+			version(stdout, argv0), exit(0);
+		else
+		{
+			fprintf(stderr, "%s: unknown option -- '%s'\n", argv0, arg);
+			fprintf(stderr, "Try '%s --help' for more information.\n", argv0);
+			exit(1);
+		}
+	}
+
+	compact_arguments(&argc, &argv);
+
+	if ( argc == 1 )
+		errx(1, "missing file operand");
+
+	if ( !opt_a && !opt_m )
+	{
+		opt_a = true;
+		opt_m = true;
+	}
+
+	struct timespec times[2] =
+	{
+		timespec_make(0, UTIME_NOW),
+		timespec_make(0, UTIME_NOW),
+	};
+
+	if ( opt_r )
+	{
+		struct stat st;
+		if ( stat(opt_r, &st) < 0 )
+			err(1, "%s", opt_r);
+		times[0] = st.st_atim;
+		times[1] = st.st_mtim;
+	}
+
+	if ( !opt_a )
+		times[0] = timespec_make(0, UTIME_OMIT);
+	if ( !opt_m )
+		times[1] = timespec_make(0, UTIME_OMIT);
+
+	for ( int i = 1; i < argc; i++ )
+	{
+		const char* path = argv[i];
+		if ( utimens(path, times) < 0 )
+		{
+			if ( errno == ENOENT )
+			{
+				if ( opt_c )
+					continue;
+				int fd;
+				if ( (fd = open(path, O_CREAT | O_RDWR, 0666)) < 0 )
+					err(1, "%s", opt_r);
+				if ( futimens(fd, times) < 0 )
+					err(1, "%s", opt_r);
+				close(fd);
+			}
+			else
+				err(1, "%s", path);
+		}
+	}
+
+	return 0;
+}