diff options
Diffstat (limited to 'tail.c')
| -rw-r--r-- | tail.c | 251 |
1 files changed, 0 insertions, 251 deletions
@@ -1,251 +0,0 @@ -/* vi: set sw=4 ts=4: */ -/* - * 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 - * - */ - - -#include <fcntl.h> -#include <getopt.h> -#include <string.h> -#include <stdlib.h> -#include <unistd.h> -#include <sys/types.h> -#include "busybox.h" - -static const struct suffix_mult tail_suffixes[] = { - { "b", 512 }, - { "k", 1024 }, - { "m", 1048576 }, - { NULL, 0 } -}; - -static const int BYTES = 0; -static const int LINES = 1; - -static char *tailbuf; -static int taillen; -static int newline; - -static void tailbuf_append(char *buf, int len) -{ - tailbuf = xrealloc(tailbuf, taillen + len); - memcpy(tailbuf + taillen, buf, len); - taillen += len; -} - -static void tailbuf_trunc(void) -{ - char *s; - s = memchr(tailbuf, '\n', taillen); - memmove(tailbuf, s + 1, taillen - ((s + 1) - tailbuf)); - taillen -= (s + 1) - tailbuf; - newline = 0; -} - -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; - - while ((opt = getopt(argc, argv, "c:fhn:q:s:v")) > 0) { - switch (opt) { - case 'f': - follow = 1; - break; -#ifdef BB_FEATURE_FANCY_TAIL - case 'c': - units = BYTES; - /* FALLS THROUGH */ -#endif - case 'n': - count = parse_number(optarg, tail_suffixes); - if (count < 0) - count = -count; - if (optarg[0] == '+') - from_top = 1; - break; -#ifdef BB_FEATURE_FANCY_TAIL - case 'q': - hide_headers = 1; - break; - case 's': - sleep_period = parse_number(optarg, 0); - break; - case 'v': - show_headers = 1; - break; -#endif - default: - 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; - } - } - } - -#ifdef BB_FEATURE_FANCY_TAIL - /* tail the files */ - if (!from_top && units == BYTES) - tailbuf = xmalloc(count); -#endif - - for (i = 0; i < nfiles; i++) { - if (fds[i] == -1) - continue; - if (!count) { - lseek(fds[i], 0, SEEK_END); - 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 (from_top) { -#ifdef BB_FEATURE_FANCY_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); - break; - } - } - } - } - if (full_write(STDOUT_FILENO, buf + nread - nwrite, - nwrite) < 0) { - perror_msg("write"); - status = EXIT_FAILURE; - break; - } - } else { -#ifdef BB_FEATURE_FANCY_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); - } - 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; - } - 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; - } - -#ifdef BB_FEATURE_FANCY_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; - } - } -#endif - - if (!from_top && units == LINES) { - if (full_write(STDOUT_FILENO, tailbuf, taillen) < 0) { - perror_msg("write"); - status = EXIT_FAILURE; - } - } - - taillen = 0; - } - - while (follow) { - sleep(sleep_period); - - for (i = 0; i < nfiles; i++) { - if (fds[i] == -1) - continue; - - if ((nread = safe_read(fds[i], buf, sizeof(buf))) > 0) { - if (show_headers || (!hide_headers && nfiles > 1)) - printf("\n==> %s <==\n", argv[optind + i]); - - do { - full_write(STDOUT_FILENO, buf, nread); - } while ((nread = safe_read(fds[i], buf, sizeof(buf))) > 0); - } - - if (nread < 0) { - perror_msg("read"); - status = EXIT_FAILURE; - } - } - } - - return status; -} |