X-Git-Url: https://git.librecmc.org/?a=blobdiff_plain;f=coreutils%2Ftail.c;h=48abc4b847c7460b278fc5b0ae89a34c2a6f9118;hb=5fe8d5b9c5930497ecf47817ec3af66bebec52c0;hp=ff77bde77e69b0ea206d9bea8a270cd850dd72a6;hpb=3e6ff9017f5aa4ea41de2520a3f6d29fb20e0332;p=oweals%2Fbusybox.git diff --git a/coreutils/tail.c b/coreutils/tail.c index ff77bde77..48abc4b84 100644 --- a/coreutils/tail.c +++ b/coreutils/tail.c @@ -2,32 +2,35 @@ /* * Mini tail implementation for busybox * - * * Copyright (C) 2001 by Matt Kraai * - * 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. */ +/* 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 -#include -#include +/* 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 #include +#include +#include #include -#include +#include +#include #include "busybox.h" static const struct suffix_mult tail_suffixes[] = { @@ -37,210 +40,283 @@ static const struct suffix_mult tail_suffixes[] = { { 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(); + } +} -static 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(); + } } -static 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; + + 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; - while ((opt = getopt(argc, argv, "c:fhn:q:s:v")) > 0) { +#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; + } + } - for (i = 0; i < nfiles; i++) { - if (fds[i] == -1) + buf = tailbuf = xmalloc(tailbufsize); + + 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;