Ported bsd truncate(1)

commands/simple/Makefile

@@ -184,6 +184,7 @@ ALL	= \
 	time \
 	touch \
 	tr \
+	truncate \
 	treecmp \
 	tsort \
 	ttt \
@@ -794,6 +795,10 @@ treecmp:	treecmp.c
 	$(CCLD) -o $@ $?
 	@install -S 4kw $@
 
+truncate:	truncate.c
+	$(CCLD) -o $@ $?
+	@install -S 4kw $@
+
 ttt:	ttt.c
 	$(CCLD) -o $@ $?
 	@install -S 4kw $@
@@ -1045,6 +1050,7 @@ install:	\
 	/usr/bin/touch \
 	/usr/bin/tr \
 	/usr/bin/treecmp \
+	/usr/bin/truncate \
 	/usr/bin/tsort \
 	/usr/bin/ttt \
 	/usr/bin/tty \
@@ -1568,6 +1574,9 @@ install:	\
 /usr/bin/treecmp:	treecmp
 	install -cs -o bin $? $@
 
+/usr/bin/truncate:	truncate
+	install -cs -o bin $? $@
+
 /usr/bin/tsort:	tsort
 	install -cs -o bin $? $@
 

commands/simple/truncate.c

@@ -0,0 +1,208 @@
+/*
+ * Copyright (c) 2000 Sheldon Hearn <sheldonh@FreeBSD.org>.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ */
+
+#include <sys/stat.h>
+
+#include <ctype.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+
+static off_t	parselength(char *, off_t *);
+static void	usage(void);
+
+static int	no_create;
+static int	do_relative;
+static int	do_refer;
+static int	got_size;
+
+int
+main(int argc, char **argv)
+{
+	struct stat	sb;
+	mode_t	omode;
+	off_t	oflow, rsize, sz, tsize;
+	int	ch, error, fd, oflags;
+	char   *fname, *rname;
+
+	rsize = tsize = 0;
+	error = 0;
+	rname = NULL;
+	while ((ch = getopt(argc, argv, "cr:s:")) != -1)
+		switch (ch) {
+		case 'c':
+			no_create = 1;
+			break;
+		case 'r':
+			do_refer = 1;
+			rname = optarg;
+			break;
+		case 's':
+			if (parselength(optarg, &sz) == -1) {
+				fprintf(stderr,
+				    "invalid size argument `%s'", optarg);
+				   exit(EXIT_FAILURE);
+				  }
+			if (*optarg == '+' || *optarg == '-')
+				do_relative = 1;
+			got_size = 1;
+			break;
+		default:
+			usage();
+			/* NOTREACHED */
+		}
+
+	argv += optind;
+	argc -= optind;
+
+	/*
+	 * Exactly one of do_refer or got_size must be specified.  Since
+	 * do_relative implies got_size, do_relative and do_refer are
+	 * also mutually exclusive.  See usage() for allowed invocations.
+	 */
+	if (do_refer + got_size != 1 || argc < 1)
+		usage();
+	if (do_refer) {
+		if (stat(rname, &sb) == -1) {
+			fprintf(stderr, "%s", rname);
+			exit(EXIT_FAILURE);
+		}
+		tsize = sb.st_size;
+	} else if (do_relative)
+		rsize = sz;
+	else
+		tsize = sz;
+
+	if (no_create)
+		oflags = O_WRONLY;
+	else
+		oflags = O_WRONLY | O_CREAT;
+	omode = S_IRUSR | S_IWUSR | S_IRGRP | S_IROTH;
+
+	while ((fname = *argv++) != NULL) {
+		if ((fd = open(fname, oflags, omode)) == -1) {
+			if (errno != ENOENT) {
+				perror(fname);
+				error++;
+			}
+			continue;
+		}
+		if (do_relative) {
+			if (fstat(fd, &sb) == -1) {
+				perror(fname);
+				error++;
+				continue;
+			}
+			oflow = sb.st_size + rsize;
+			if (oflow < (sb.st_size + rsize)) {
+				errno = EFBIG;
+				perror(fname);
+				error++;
+				continue;
+			}
+			tsize = oflow;
+		}
+		if (tsize < 0)
+			tsize = 0;
+
+		if (ftruncate(fd, tsize) == -1) {
+			perror(fname);
+			error++;
+			continue;
+		}
+
+		close(fd);
+	}
+
+	return error ? EXIT_FAILURE : EXIT_SUCCESS;
+}
+
+/*
+ * Return the numeric value of a string given in the form [+-][0-9]+[GMK]
+ * or -1 on format error or overflow.
+ */
+static off_t
+parselength(char *ls, off_t *sz)
+{
+	off_t	length, oflow;
+	int	lsign;
+
+	length = 0;
+	lsign = 1;
+
+	switch (*ls) {
+	case '-':
+		lsign = -1;
+	case '+':
+		ls++;
+	}
+
+#define	ASSIGN_CHK_OFLOW(x, y)	if (x < y) return -1; y = x
+	/*
+	 * Calculate the value of the decimal digit string, failing
+	 * on overflow.
+	 */
+	while (isdigit(*ls)) {
+		oflow = length * 10 + *ls++ - '0';
+		ASSIGN_CHK_OFLOW(oflow, length);
+	}
+
+	switch (*ls) {
+	case 'G':
+	case 'g':
+		oflow = length * 1024;
+		ASSIGN_CHK_OFLOW(oflow, length);
+	case 'M':
+	case 'm':
+		oflow = length * 1024;
+		ASSIGN_CHK_OFLOW(oflow, length);
+	case 'K':
+	case 'k':
+		if (ls[1] != '\0')
+			return -1;
+		oflow = length * 1024;
+		ASSIGN_CHK_OFLOW(oflow, length);
+	case '\0':
+		break;
+	default:
+		return -1;
+	}
+
+	*sz = length * lsign;
+	return 0;
+}
+
+static void
+usage(void)
+{
+	fprintf(stderr, "%s\n%s\n",
+	    "usage: truncate [-c] -s [+|-]size[K|k|M|m|G|g] file ...",
+	    "       truncate [-c] -r rfile file ...");
+	exit(EXIT_FAILURE);
+}