summaryrefslogtreecommitdiff
path: root/usr.bin/tail/tail.c
diff options
context:
space:
mode:
Diffstat (limited to 'usr.bin/tail/tail.c')
-rw-r--r--usr.bin/tail/tail.c323
1 files changed, 323 insertions, 0 deletions
diff --git a/usr.bin/tail/tail.c b/usr.bin/tail/tail.c
new file mode 100644
index 0000000..dff9559
--- /dev/null
+++ b/usr.bin/tail/tail.c
@@ -0,0 +1,323 @@
+/*-
+ * Copyright (c) 1991, 1993
+ * The Regents of the University of California. All rights reserved.
+ *
+ * This code is derived from software contributed to Berkeley by
+ * Edward Sze-Tyan Wang.
+ *
+ * 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.
+ * 3. Neither the name of the University nor the names of its contributors
+ * may be used to endorse or promote products derived from this software
+ * without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS 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 REGENTS 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/cdefs.h>
+#ifndef lint
+__COPYRIGHT("@(#) Copyright (c) 1991, 1993\
+ The Regents of the University of California. All rights reserved.");
+#endif /* not lint */
+
+#ifndef lint
+#if 0
+static char sccsid[] = "@(#)tail.c 8.1 (Berkeley) 6/6/93";
+#endif
+__RCSID("$NetBSD: tail.c,v 1.20 2018/03/06 03:33:26 eadler Exp $");
+#endif /* not lint */
+
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <errno.h>
+#include <unistd.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include "extern.h"
+
+int fflag, rflag, rval;
+const char *fname;
+
+static void obsolete(char **);
+static void usage(void) __dead;
+
+int
+main(int argc, char *argv[])
+{
+ struct stat sb;
+ FILE *fp;
+ off_t off;
+ enum STYLE style;
+ int ch, first;
+ char *p;
+ int qflag = 0;
+ int vflag = 0;
+
+ setprogname(argv[0]);
+ off = 0;
+ /*
+ * Tail's options are weird. First, -n10 is the same as -n-10, not
+ * -n+10. Second, the number options are 1 based and not offsets,
+ * so -n+1 is the first line, and -c-1 is the last byte. Third, the
+ * number options for the -r option specify the number of things that
+ * get displayed, not the starting point in the file. The one major
+ * incompatibility in this version as compared to historical versions
+ * is that the 'r' option couldn't be modified by the -lbc options,
+ * i.e., it was always done in lines. This version treats -rc as a
+ * number of characters in reverse order. Finally, the default for
+ * -r is the entire file, not 10 lines.
+ */
+#define ARG(units, forward, backward) { \
+ if (style) \
+ usage(); \
+ off = strtoll(optarg, &p, 10) * (units); \
+ if (*p) \
+ xerrx(1, "illegal offset -- %s", optarg); \
+ switch(optarg[0]) { \
+ case '+': \
+ if (off) \
+ off -= (units); \
+ style = (forward); \
+ break; \
+ case '-': \
+ off = -off; \
+ /* FALLTHROUGH */ \
+ default: \
+ style = (backward); \
+ break; \
+ } \
+}
+
+ obsolete(argv);
+ style = NOTSET;
+ if (strcmp(getprogname(), "tac") == 0) {
+ qflag = 1;
+ vflag = 0;
+ rflag = 1;
+ argc -= 1;
+ argv += 1;
+ } else { /* tail */
+ while ((ch = getopt(argc, argv, "Fb:c:fn:rqv")) != -1)
+ switch(ch) {
+ case 'F':
+ fflag = 2;
+ break;
+ case 'b':
+ ARG(512, FBYTES, RBYTES);
+ break;
+ case 'c':
+ ARG(1, FBYTES, RBYTES);
+ break;
+ case 'f':
+ fflag = 1;
+ break;
+ case 'n':
+ ARG(1, FLINES, RLINES);
+ break;
+ case 'r':
+ rflag = 1;
+ break;
+ case 'q':
+ qflag = 1;
+ vflag = 0;
+ break;
+ case 'v':
+ qflag = 0;
+ vflag = 1;
+ break;
+ case '?':
+ default:
+ usage();
+ }
+ argc -= optind;
+ argv += optind;
+ }
+
+ if (fflag && argc > 1)
+ xerrx(1,
+ "-f and -F options only appropriate for a single file");
+
+ /*
+ * If displaying in reverse, don't permit follow option, and convert
+ * style values.
+ */
+ if (rflag) {
+ if (fflag)
+ usage();
+ if (style == FBYTES)
+ style = RBYTES;
+ else if (style == FLINES)
+ style = RLINES;
+ }
+
+ /*
+ * If style not specified, the default is the whole file for -r, and
+ * the last 10 lines if not -r.
+ */
+ if (style == NOTSET) {
+ if (rflag) {
+ off = 0;
+ style = REVERSE;
+ } else {
+ off = 10;
+ style = RLINES;
+ }
+ }
+ if (*argv)
+ for (first = 1; (fname = *argv++) != NULL;) {
+ if ((fp = fopen(fname, "r")) == NULL ||
+ fstat(fileno(fp), &sb)) {
+ ierr();
+ continue;
+ }
+ if (vflag || (qflag == 0 && argc > 1)) {
+ (void)printf("%s==> %s <==\n",
+ first ? "" : "\n", fname);
+ first = 0;
+ (void)fflush(stdout);
+ }
+
+ if (rflag)
+ reverse(fp, style, off, &sb);
+ else
+ forward(fp, style, off, &sb);
+ (void)fclose(fp);
+ }
+ else {
+ fname = "stdin";
+
+ if (fstat(fileno(stdin), &sb)) {
+ ierr();
+ exit(1);
+ }
+
+ /*
+ * Determine if input is a pipe. 4.4BSD will set the SOCKET
+ * bit in the st_mode field for pipes. Fix this then.
+ */
+ if (lseek(fileno(stdin), (off_t)0, SEEK_CUR) == -1 &&
+ errno == ESPIPE) {
+ errno = 0;
+ fflag = 0; /* POSIX.2 requires this. */
+ }
+
+ if (rflag)
+ reverse(stdin, style, off, &sb);
+ else
+ forward(stdin, style, off, &sb);
+ }
+ exit(rval);
+}
+
+/*
+ * Convert the obsolete argument form into something that getopt can handle.
+ * This means that anything of the form [+-][0-9][0-9]*[lbc][fr] that isn't
+ * the option argument for a -b, -c or -n option gets converted.
+ */
+static void
+obsolete(char *argv[])
+{
+ char *ap, *p, *t;
+ size_t len;
+ char *start;
+
+ while ((ap = *++argv) != NULL) {
+ /* Return if "--" or not an option of any form. */
+ if (ap[0] != '-') {
+ if (ap[0] != '+')
+ return;
+ } else if (ap[1] == '-')
+ return;
+
+ switch (*++ap) {
+ /* Old-style option. */
+ case '0': case '1': case '2': case '3': case '4':
+ case '5': case '6': case '7': case '8': case '9':
+
+ /* Malloc space for dash, new option and argument. */
+ len = strlen(*argv);
+ if ((start = p = malloc(len + 3)) == NULL)
+ xerr(1, "malloc");
+ *p++ = '-';
+
+ /*
+ * Go to the end of the option argument. Save off any
+ * trailing options (-3lf) and translate any trailing
+ * output style characters.
+ */
+ t = *argv + len - 1;
+ if (*t == 'f' || *t == 'r') {
+ *p++ = *t;
+ *t-- = '\0';
+ }
+ switch(*t) {
+ case 'b':
+ *p++ = 'b';
+ *t = '\0';
+ break;
+ case 'c':
+ *p++ = 'c';
+ *t = '\0';
+ break;
+ case 'l':
+ *t = '\0';
+ /* FALLTHROUGH */
+ case '0': case '1': case '2': case '3': case '4':
+ case '5': case '6': case '7': case '8': case '9':
+ *p++ = 'n';
+ break;
+ default:
+ xerrx(1, "illegal option -- %s", *argv);
+ }
+ *p++ = *argv[0];
+ (void)strcpy(p, ap);
+ *argv = start;
+ continue;
+
+ /*
+ * Options w/ arguments, skip the argument and continue
+ * with the next option.
+ */
+ case 'b':
+ case 'c':
+ case 'n':
+ if (!ap[1])
+ ++argv;
+ /* FALLTHROUGH */
+ /* Options w/o arguments, continue with the next option. */
+ case 'f':
+ case 'r':
+ continue;
+
+ /* Illegal option, return and let getopt handle it. */
+ default:
+ return;
+ }
+ }
+}
+
+static void
+usage(void)
+{
+ (void)fprintf(stderr,
+ "Usage: %s [-qv] [-f | -F | -r] [-b # | -c # | -n #] [file ...]\n",
+ getprogname());
+ exit(1);
+}
generated by cgit v1.2.3-60-g2f50 (git 2.42.0) at 2024-06-28 22:08:50 +0000