/*
* Mini tail implementation for busybox
*
- *
* Copyright (C) 2001 by Matt Kraai <kraai@alumni.carnegiemellon.edu>
*
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation; either version 2 of the License, or
- * (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
- * General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program; if not, write to the Free Software
- * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
- *
+ * Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
*/
-#include "busybox.h"
+/* BB_AUDIT SUSv3 compliant (need fancy for -c) */
+/* BB_AUDIT GNU compatible -c, -q, and -v options in 'fancy' configuration. */
+/* http://www.opengroup.org/onlinepubs/007904975/utilities/tail.html */
-#include <fcntl.h>
-#include <getopt.h>
-#include <string.h>
+/* Mar 16, 2003 Manuel Novoa III (mjn3@codepoet.org)
+ *
+ * Pretty much rewritten to fix numerous bugs and reduce realloc() calls.
+ * Bugs fixed (although I may have forgotten one or two... it was pretty bad)
+ * 1) mixing printf/write without fflush()ing stdout
+ * 2) no check that any open files are present
+ * 3) optstring had -q taking an arg
+ * 4) no error checking on write in some cases, and a warning even then
+ * 5) q and s interaction bug
+ * 6) no check for lseek error
+ * 7) lseek attempted when count==0 even if arg was +0 (from top)
+ */
+
+#include <stdio.h>
#include <stdlib.h>
+#include <string.h>
+#include <ctype.h>
#include <unistd.h>
-#include <sys/types.h>
+#include <fcntl.h>
+#include <sys/stat.h>
+#include "busybox.h"
static const struct suffix_mult tail_suffixes[] = {
{ "b", 512 },
{ NULL, 0 }
};
-static const int BYTES = 0;
-static const int LINES = 1;
+static int status;
-static char *tailbuf;
-static int taillen;
-static int newline;
+static void tail_xprint_header(const char *fmt, const char *filename)
+{
+ /* If we get an output error, there is really no sense in continuing. */
+ if (dprintf(STDOUT_FILENO, fmt, filename) < 0) {
+ bb_perror_nomsg_and_die();
+ }
+}
-void tailbuf_append(char *buf, int len)
+/* len should probably be size_t */
+static void tail_xbb_full_write(const char *buf, size_t len)
{
- tailbuf = xrealloc(tailbuf, taillen + len);
- memcpy(tailbuf + taillen, buf, len);
- taillen += len;
+ /* If we get a write error, there is really no sense in continuing. */
+ if (bb_full_write(STDOUT_FILENO, buf, len) < 0) {
+ bb_perror_nomsg_and_die();
+ }
}
-void tailbuf_trunc()
+static ssize_t tail_read(int fd, char *buf, size_t count)
{
- char *s;
- s = memchr(tailbuf, '\n', taillen);
- memmove(tailbuf, s + 1, taillen - ((s + 1) - tailbuf));
- taillen -= (s + 1) - tailbuf;
- newline = 0;
+ ssize_t r;
+ off_t current,end;
+ struct stat sbuf;
+
+ end = current = lseek(fd, 0, SEEK_CUR);
+ if (!fstat(fd, &sbuf))
+ end = sbuf.st_size;
+ lseek(fd, end < current ? 0 : current, SEEK_SET);
+ if ((r = safe_read(fd, buf, count)) < 0) {
+ bb_perror_msg("read");
+ status = EXIT_FAILURE;
+ }
+
+ return r;
}
+static const char tail_opts[] =
+ "fn:c:"
+#if ENABLE_FEATURE_FANCY_TAIL
+ "qs:v"
+#endif
+ ;
+
+static const char header_fmt[] = "\n==> %s <==\n";
+
int tail_main(int argc, char **argv)
{
- int from_top = 0, units = LINES, count = 10, sleep_period = 1;
- int show_headers = 0, hide_headers = 0, follow = 0;
- int *fds, nfiles = 0, status = EXIT_SUCCESS, nread, nwrite, seen = 0;
- char *s, *start, *end, buf[BUFSIZ];
- int i, opt;
+ long count = 10;
+ unsigned int sleep_period = 1;
+ int from_top = 0;
+ int follow = 0;
+ int header_threshhold = 1;
+ int count_bytes = 0;
- while ((opt = getopt(argc, argv, "c:fhn:q:s:v")) > 0) {
+ char *tailbuf;
+ size_t tailbufsize;
+ int taillen = 0;
+ int newline = 0;
+
+ int *fds, nfiles, nread, nwrite, seen, i, opt;
+ char *s, *buf;
+ const char *fmt;
+
+#if !ENABLE_DEBUG_YANK_SUSv2 || ENABLE_FEATURE_FANCY_TAIL
+ /* Allow legacy syntax of an initial numeric option without -n. */
+ if (argc >=2 && ((argv[1][0] == '+') || ((argv[1][0] == '-')
+ /* && (isdigit)(argv[1][1]) */
+ && (((unsigned int)(argv[1][1] - '0')) <= 9))))
+ {
+ optind = 2;
+ optarg = argv[1];
+ goto GET_COUNT;
+ }
+#endif
+
+ while ((opt = getopt(argc, argv, tail_opts)) > 0) {
switch (opt) {
case 'f':
follow = 1;
break;
-#ifndef BB_FEATURE_SIMPLE_TAIL
case 'c':
- units = BYTES;
+ count_bytes = 1;
/* FALLS THROUGH */
-#endif
case 'n':
- count = parse_number(optarg, tail_suffixes);
- if (count < 0)
- count = -count;
- if (optarg[0] == '+')
+#if !ENABLE_DEBUG_YANK_SUSv2 || ENABLE_FEATURE_FANCY_TAIL
+ GET_COUNT:
+#endif
+ count = bb_xgetlarg10_sfx(optarg, tail_suffixes);
+ /* Note: Leading whitespace is an error trapped above. */
+ if (*optarg == '+') {
from_top = 1;
+ } else {
+ from_top = 0;
+ }
+ if (count < 0) {
+ count = -count;
+ }
break;
-#ifndef BB_FEATURE_SIMPLE_TAIL
+#if ENABLE_FEATURE_FANCY_TAIL
case 'q':
- hide_headers = 1;
+ header_threshhold = INT_MAX;
break;
case 's':
- sleep_period = parse_number(optarg, 0);
+ sleep_period =bb_xgetularg10_bnd(optarg, 0, UINT_MAX);
break;
case 'v':
- show_headers = 1;
+ header_threshhold = 0;
break;
#endif
default:
- show_usage();
+ bb_show_usage();
}
}
/* open all the files */
fds = (int *)xmalloc(sizeof(int) * (argc - optind + 1));
- if (argc == optind) {
- fds[nfiles++] = STDIN_FILENO;
- argv[optind] = "standard input";
- } else {
- for (i = optind; i < argc; i++) {
- if (strcmp(argv[i], "-") == 0) {
- fds[nfiles++] = STDIN_FILENO;
- argv[i] = "standard input";
- } else if ((fds[nfiles++] = open(argv[i], O_RDONLY)) < 0) {
- perror_msg("%s", argv[i]);
- status = EXIT_FAILURE;
- }
+
+ argv += optind;
+ nfiles = i = 0;
+
+ if ((argc -= optind) == 0) {
+ struct stat statbuf;
+
+ if (!fstat(STDIN_FILENO, &statbuf) && S_ISFIFO(statbuf.st_mode)) {
+ follow = 0;
}
+ /* --argv; */
+ *argv = (char *) bb_msg_standard_input;
+ goto DO_STDIN;
}
-
-#ifndef BB_FEATURE_SIMPLE_TAIL
+
+ do {
+ if ((argv[i][0] == '-') && !argv[i][1]) {
+ DO_STDIN:
+ fds[nfiles] = STDIN_FILENO;
+ } else if ((fds[nfiles] = open(argv[i], O_RDONLY)) < 0) {
+ bb_perror_msg("%s", argv[i]);
+ status = EXIT_FAILURE;
+ continue;
+ }
+ argv[nfiles] = argv[i];
+ ++nfiles;
+ } while (++i < argc);
+
+ if (!nfiles) {
+ bb_error_msg_and_die("no files");
+ }
+
+ tailbufsize = BUFSIZ;
+
/* tail the files */
- if (!from_top && units == BYTES)
- tailbuf = xmalloc(count);
-#endif
+ if (from_top < count_bytes) { /* Each is 0 or 1, so true iff 0 < 1. */
+ /* Hence, !from_top && count_bytes */
+ if (tailbufsize < count) {
+ tailbufsize = count + BUFSIZ;
+ }
+ }
+
+ buf = tailbuf = xmalloc(tailbufsize);
- for (i = 0; i < nfiles; i++) {
- if (fds[i] == -1)
+ fmt = header_fmt + 1; /* Skip header leading newline on first output. */
+ i = 0;
+ do {
+ /* Be careful. It would be possible to optimize the count-bytes
+ * case if the file is seekable. If you do though, remember that
+ * starting file position may not be the beginning of the file.
+ * Beware of backing up too far. See example in wc.c.
+ */
+ if ((!(count|from_top)) && (lseek(fds[i], 0, SEEK_END) >= 0)) {
continue;
- seen = 0;
- if (show_headers || (!hide_headers && nfiles > 1))
- printf("%s==> %s <==\n", i == 0 ? "" : "\n", argv[optind + i]);
- while ((nread = safe_read(fds[i], buf, sizeof(buf))) > 0) {
+ }
+
+ if (nfiles > header_threshhold) {
+ tail_xprint_header(fmt, argv[i]);
+ fmt = header_fmt;
+ }
+
+ buf = tailbuf;
+ taillen = 0;
+ seen = 1;
+ newline = 0;
+
+ while ((nread = tail_read(fds[i], buf, tailbufsize-taillen)) > 0) {
if (from_top) {
-#ifndef BB_FEATURE_SIMPLE_TAIL
- if (units == BYTES) {
- if (count - 1 <= seen)
- nwrite = nread;
- else if (count - 1 <= seen + nread)
- nwrite = nread + seen - (count - 1);
- else
- nwrite = 0;
- seen += nread;
- } else {
-#else
- {
-#endif
- if (count - 1 <= seen)
- nwrite = nread;
- else {
- nwrite = 0;
- for (s = memchr(buf, '\n', nread); s != NULL;
- s = memchr(s+1, '\n', nread - (s + 1 - buf))) {
- if (count - 1 <= ++seen) {
- nwrite = nread - (s + 1 - buf);
+ nwrite = nread;
+ if (seen < count) {
+ if (count_bytes) {
+ nwrite -= (count - seen);
+ seen = count;
+ } else {
+ s = buf;
+ do {
+ --nwrite;
+ if ((*s++ == '\n') && (++seen == count)) {
break;
}
- }
+ } while (nwrite);
}
}
- if (full_write(STDOUT_FILENO, buf + nread - nwrite,
- nwrite) < 0) {
- perror_msg("write");
- status = EXIT_FAILURE;
- break;
- }
- } else {
-#ifndef BB_FEATURE_SIMPLE_TAIL
- if (units == BYTES) {
- if (nread < count) {
- memmove(tailbuf, tailbuf + nread, count - nread);
- memcpy(tailbuf + count - nread, buf, nread);
- } else {
- memcpy(tailbuf, buf + nread - count, count);
+ tail_xbb_full_write(buf + nread - nwrite, nwrite);
+ } else if (count) {
+ if (count_bytes) {
+ taillen += nread;
+ if (taillen > count) {
+ memmove(tailbuf, tailbuf + taillen - count, count);
+ taillen = count;
}
- seen += nread;
} else {
-#else
- {
-#endif
- for (start = buf, end = memchr(buf, '\n', nread);
- end != NULL; start = end+1,
- end = memchr(start, '\n', nread - (start - buf))) {
- if (newline && count <= seen)
- tailbuf_trunc();
- tailbuf_append(start, end - start + 1);
- seen++;
- newline = 1;
+ int k = nread;
+ int nbuf = 0;
+
+ while (k) {
+ --k;
+ if (buf[k] == '\n') {
+ ++nbuf;
+ }
}
- if (newline && count <= seen && nread - (start - buf) > 0)
- tailbuf_trunc();
- tailbuf_append(start, nread - (start - buf));
- }
- }
- }
- if (nread < 0) {
- perror_msg("read");
- status = EXIT_FAILURE;
- }
+ if (newline + nbuf < count) {
+ newline += nbuf;
+ taillen += nread;
+
+ } else {
+ int extra = 0;
+ if (buf[nread-1] != '\n') {
+ extra = 1;
+ }
-#ifndef BB_FEATURE_SIMPLE_TAIL
- if (!from_top && units == BYTES) {
- if (count < seen)
- seen = count;
- if (full_write(STDOUT_FILENO, tailbuf + count - seen, seen) < 0) {
- perror_msg("write");
- status = EXIT_FAILURE;
+ k = newline + nbuf + extra - count;
+ s = tailbuf;
+ while (k) {
+ if (*s == '\n') {
+ --k;
+ }
+ ++s;
+ }
+
+ taillen += nread - (s - tailbuf);
+ memmove(tailbuf, s, taillen);
+ newline = count - extra;
+ }
+ if (tailbufsize < taillen + BUFSIZ) {
+ tailbufsize = taillen + BUFSIZ;
+ tailbuf = xrealloc(tailbuf, tailbufsize);
+ }
+ }
+ buf = tailbuf + taillen;
}
}
-#endif
- if (!from_top && units == LINES) {
- if (full_write(STDOUT_FILENO, tailbuf, taillen) < 0) {
- perror_msg("write");
- status = EXIT_FAILURE;
- }
+ if (!from_top) {
+ tail_xbb_full_write(tailbuf, taillen);
}
taillen = 0;
- }
-
- while (follow) {
- sleep(sleep_period);
+ } while (++i < nfiles);
- for (i = 0; i < nfiles; i++) {
- if (fds[i] == -1)
- continue;
+ buf = xrealloc(tailbuf, BUFSIZ);
- if ((nread = safe_read(fds[i], buf, sizeof(buf))) > 0) {
- if (show_headers || (!hide_headers && nfiles > 1))
- printf("\n==> %s <==\n", argv[optind + i]);
+ fmt = NULL;
- do {
- full_write(STDOUT_FILENO, buf, nread);
- } while ((nread = safe_read(fds[i], buf, sizeof(buf))) > 0);
+ while (follow) {
+ sleep(sleep_period);
+ i = 0;
+ do {
+ if (nfiles > header_threshhold) {
+ fmt = header_fmt;
}
-
- if (nread < 0) {
- perror_msg("read");
- status = EXIT_FAILURE;
+ while ((nread = tail_read(fds[i], buf, sizeof(buf))) > 0) {
+ if (fmt) {
+ tail_xprint_header(fmt, argv[i]);
+ fmt = NULL;
+ }
+ tail_xbb_full_write(buf, nread);
}
- }
+ } while (++i < nfiles);
}
return status;
projects / oweals / busybox.git / blobdiff