Erik Andersen | e49d5ec | 2000-02-08 19:58:47 +0000 | [diff] [blame] | 1 | /* vi: set sw=4 ts=4: */ |
Matt Kraai | 55bccf3 | 2001-01-05 02:57:53 +0000 | [diff] [blame] | 2 | /* |
| 3 | * Mini tail implementation for busybox |
| 4 | * |
Matt Kraai | 55bccf3 | 2001-01-05 02:57:53 +0000 | [diff] [blame] | 5 | * Copyright (C) 2001 by Matt Kraai <kraai@alumni.carnegiemellon.edu> |
| 6 | * |
Denys Vlasenko | 0ef64bd | 2010-08-16 20:14:46 +0200 | [diff] [blame] | 7 | * Licensed under GPLv2 or later, see file LICENSE in this source tree. |
Erik Andersen | 3fe39dc | 2000-01-25 18:13:53 +0000 | [diff] [blame] | 8 | */ |
Matt Kraai | 55bccf3 | 2001-01-05 02:57:53 +0000 | [diff] [blame] | 9 | |
Manuel Novoa III | cad5364 | 2003-03-19 09:13:01 +0000 | [diff] [blame] | 10 | /* BB_AUDIT SUSv3 compliant (need fancy for -c) */ |
| 11 | /* BB_AUDIT GNU compatible -c, -q, and -v options in 'fancy' configuration. */ |
| 12 | /* http://www.opengroup.org/onlinepubs/007904975/utilities/tail.html */ |
Eric Andersen | abc0f4f | 1999-12-08 23:19:36 +0000 | [diff] [blame] | 13 | |
Manuel Novoa III | cad5364 | 2003-03-19 09:13:01 +0000 | [diff] [blame] | 14 | /* Mar 16, 2003 Manuel Novoa III (mjn3@codepoet.org) |
| 15 | * |
| 16 | * Pretty much rewritten to fix numerous bugs and reduce realloc() calls. |
| 17 | * Bugs fixed (although I may have forgotten one or two... it was pretty bad) |
| 18 | * 1) mixing printf/write without fflush()ing stdout |
| 19 | * 2) no check that any open files are present |
| 20 | * 3) optstring had -q taking an arg |
| 21 | * 4) no error checking on write in some cases, and a warning even then |
| 22 | * 5) q and s interaction bug |
| 23 | * 6) no check for lseek error |
| 24 | * 7) lseek attempted when count==0 even if arg was +0 (from top) |
| 25 | */ |
| 26 | |
Denys Vlasenko | af0255f | 2013-02-25 01:24:32 +0100 | [diff] [blame] | 27 | //kbuild:lib-$(CONFIG_TAIL) += tail.o |
Denys Vlasenko | af0255f | 2013-02-25 01:24:32 +0100 | [diff] [blame] | 28 | |
Pere Orga | 3442538 | 2011-03-31 14:43:25 +0200 | [diff] [blame] | 29 | //usage:#define tail_trivial_usage |
| 30 | //usage: "[OPTIONS] [FILE]..." |
| 31 | //usage:#define tail_full_usage "\n\n" |
| 32 | //usage: "Print last 10 lines of each FILE (or stdin) to stdout.\n" |
| 33 | //usage: "With more than one FILE, precede each with a filename header.\n" |
Pere Orga | 3442538 | 2011-03-31 14:43:25 +0200 | [diff] [blame] | 34 | //usage: "\n -f Print data as file grows" |
Cristian Ionescu-Idbohrn | 1bdbf26 | 2014-01-09 20:00:58 +0100 | [diff] [blame] | 35 | //usage: "\n -c [+]N[kbm] Print last N bytes" |
Pere Orga | 3442538 | 2011-03-31 14:43:25 +0200 | [diff] [blame] | 36 | //usage: "\n -n N[kbm] Print last N lines" |
Denys Vlasenko | 3305c00 | 2013-02-25 07:24:44 +0100 | [diff] [blame] | 37 | //usage: "\n -n +N[kbm] Start on Nth line and print the rest" |
Pere Orga | 3442538 | 2011-03-31 14:43:25 +0200 | [diff] [blame] | 38 | //usage: IF_FEATURE_FANCY_TAIL( |
Pere Orga | 3442538 | 2011-03-31 14:43:25 +0200 | [diff] [blame] | 39 | //usage: "\n -q Never print headers" |
Cristian Ionescu-Idbohrn | 1bdbf26 | 2014-01-09 20:00:58 +0100 | [diff] [blame] | 40 | //usage: "\n -s SECONDS Wait SECONDS between reads with -f" |
Pere Orga | 3442538 | 2011-03-31 14:43:25 +0200 | [diff] [blame] | 41 | //usage: "\n -v Always print headers" |
Cristian Ionescu-Idbohrn | 1bdbf26 | 2014-01-09 20:00:58 +0100 | [diff] [blame] | 42 | //usage: "\n -F Same as -f, but keep retrying" |
Pere Orga | 3442538 | 2011-03-31 14:43:25 +0200 | [diff] [blame] | 43 | //usage: "\n" |
| 44 | //usage: "\nN may be suffixed by k (x1024), b (x512), or m (x1024^2)." |
Pere Orga | 3442538 | 2011-03-31 14:43:25 +0200 | [diff] [blame] | 45 | //usage: ) |
| 46 | //usage: |
| 47 | //usage:#define tail_example_usage |
| 48 | //usage: "$ tail -n 1 /etc/resolv.conf\n" |
| 49 | //usage: "nameserver 10.0.0.1\n" |
| 50 | |
Denis Vlasenko | b6adbf1 | 2007-05-26 19:00:18 +0000 | [diff] [blame] | 51 | #include "libbb.h" |
Denys Vlasenko | e6a2f4c | 2016-04-21 16:26:30 +0200 | [diff] [blame] | 52 | #include "common_bufsiz.h" |
Matt Kraai | 24ac017 | 2000-12-18 21:38:57 +0000 | [diff] [blame] | 53 | |
Bernhard Reutner-Fischer | d9c2d5f | 2007-04-04 20:29:15 +0000 | [diff] [blame] | 54 | struct globals { |
Denys Vlasenko | 9e933d9 | 2011-05-20 00:30:04 +0200 | [diff] [blame] | 55 | bool from_top; |
| 56 | bool exitcode; |
Denys Vlasenko | 98a4c7c | 2010-02-04 15:00:15 +0100 | [diff] [blame] | 57 | } FIX_ALIASING; |
Denys Vlasenko | e6a2f4c | 2016-04-21 16:26:30 +0200 | [diff] [blame] | 58 | #define G (*(struct globals*)bb_common_bufsiz1) |
Denys Vlasenko | 47cfbf3 | 2016-04-21 18:18:48 +0200 | [diff] [blame] | 59 | #define INIT_G() do { setup_common_bufsiz(); } while (0) |
Matt Kraai | 55bccf3 | 2001-01-05 02:57:53 +0000 | [diff] [blame] | 60 | |
Bernhard Reutner-Fischer | 73561cc | 2006-08-28 23:31:54 +0000 | [diff] [blame] | 61 | static void tail_xprint_header(const char *fmt, const char *filename) |
| 62 | { |
Denis Vlasenko | e31f721 | 2006-12-22 16:06:16 +0000 | [diff] [blame] | 63 | if (fdprintf(STDOUT_FILENO, fmt, filename) < 0) |
Bernhard Reutner-Fischer | 73561cc | 2006-08-28 23:31:54 +0000 | [diff] [blame] | 64 | bb_perror_nomsg_and_die(); |
Bernhard Reutner-Fischer | 73561cc | 2006-08-28 23:31:54 +0000 | [diff] [blame] | 65 | } |
| 66 | |
Denys Vlasenko | d87fcd4 | 2013-07-08 02:39:51 +0200 | [diff] [blame] | 67 | static ssize_t tail_read(int fd, char *buf, size_t count) |
Manuel Novoa III | cad5364 | 2003-03-19 09:13:01 +0000 | [diff] [blame] | 68 | { |
| 69 | ssize_t r; |
| 70 | |
Denis Vlasenko | 226002e | 2007-10-05 19:17:16 +0000 | [diff] [blame] | 71 | r = full_read(fd, buf, count); |
Denis Vlasenko | e31f721 | 2006-12-22 16:06:16 +0000 | [diff] [blame] | 72 | if (r < 0) { |
Bernhard Reutner-Fischer | 1b9d7c9 | 2006-06-03 22:45:37 +0000 | [diff] [blame] | 73 | bb_perror_msg(bb_msg_read_error); |
Denys Vlasenko | 9e933d9 | 2011-05-20 00:30:04 +0200 | [diff] [blame] | 74 | G.exitcode = EXIT_FAILURE; |
Manuel Novoa III | cad5364 | 2003-03-19 09:13:01 +0000 | [diff] [blame] | 75 | } |
| 76 | |
| 77 | return r; |
| 78 | } |
| 79 | |
Denys Vlasenko | ea8b252 | 2010-06-02 12:57:26 +0200 | [diff] [blame] | 80 | #define header_fmt_str "\n==> %s <==\n" |
Manuel Novoa III | cad5364 | 2003-03-19 09:13:01 +0000 | [diff] [blame] | 81 | |
Denis Vlasenko | ac678ec | 2007-04-16 22:32:04 +0000 | [diff] [blame] | 82 | static unsigned eat_num(const char *p) |
| 83 | { |
Denis Vlasenko | 368a12e | 2007-10-02 10:17:56 +0000 | [diff] [blame] | 84 | if (*p == '-') |
| 85 | p++; |
| 86 | else if (*p == '+') { |
| 87 | p++; |
Denys Vlasenko | 9e933d9 | 2011-05-20 00:30:04 +0200 | [diff] [blame] | 88 | G.from_top = 1; |
Denis Vlasenko | 368a12e | 2007-10-02 10:17:56 +0000 | [diff] [blame] | 89 | } |
Denys Vlasenko | c72b43c | 2013-07-13 23:49:45 +0200 | [diff] [blame] | 90 | return xatou_sfx(p, bkm_suffixes); |
Bernhard Reutner-Fischer | 84d2d49 | 2007-01-24 21:38:10 +0000 | [diff] [blame] | 91 | } |
| 92 | |
Denis Vlasenko | 9b49a5e | 2007-10-11 10:05:36 +0000 | [diff] [blame] | 93 | int tail_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE; |
Eric Andersen | 98bbd68 | 2000-07-31 17:05:58 +0000 | [diff] [blame] | 94 | int tail_main(int argc, char **argv) |
Eric Andersen | abc0f4f | 1999-12-08 23:19:36 +0000 | [diff] [blame] | 95 | { |
Denis Vlasenko | e31f721 | 2006-12-22 16:06:16 +0000 | [diff] [blame] | 96 | unsigned count = 10; |
Denis Vlasenko | 459903b | 2006-11-27 14:44:18 +0000 | [diff] [blame] | 97 | unsigned sleep_period = 1; |
Denis Vlasenko | 92c0b82 | 2007-05-08 17:27:17 +0000 | [diff] [blame] | 98 | const char *str_c, *str_n; |
Eric Andersen | abc0f4f | 1999-12-08 23:19:36 +0000 | [diff] [blame] | 99 | |
Manuel Novoa III | cad5364 | 2003-03-19 09:13:01 +0000 | [diff] [blame] | 100 | char *tailbuf; |
| 101 | size_t tailbufsize; |
Eric Lammerts | 3b5a664 | 2009-07-22 00:31:27 +0200 | [diff] [blame] | 102 | unsigned header_threshhold = 1; |
| 103 | unsigned nfiles; |
| 104 | int i, opt; |
Manuel Novoa III | cad5364 | 2003-03-19 09:13:01 +0000 | [diff] [blame] | 105 | |
Denis Vlasenko | e31f721 | 2006-12-22 16:06:16 +0000 | [diff] [blame] | 106 | int *fds; |
Manuel Novoa III | cad5364 | 2003-03-19 09:13:01 +0000 | [diff] [blame] | 107 | const char *fmt; |
Bartosz Golaszewski | 6493801 | 2013-10-14 20:11:55 +0200 | [diff] [blame] | 108 | int prev_fd; |
Manuel Novoa III | cad5364 | 2003-03-19 09:13:01 +0000 | [diff] [blame] | 109 | |
Denys Vlasenko | 1671424 | 2011-09-21 01:59:15 +0200 | [diff] [blame] | 110 | INIT_G(); |
| 111 | |
Denis Vlasenko | 0849207 | 2006-12-22 13:56:36 +0000 | [diff] [blame] | 112 | #if ENABLE_INCLUDE_SUSv2 || ENABLE_FEATURE_FANCY_TAIL |
Manuel Novoa III | cad5364 | 2003-03-19 09:13:01 +0000 | [diff] [blame] | 113 | /* Allow legacy syntax of an initial numeric option without -n. */ |
Denis Vlasenko | 62a90cd | 2008-03-17 09:07:36 +0000 | [diff] [blame] | 114 | if (argv[1] && (argv[1][0] == '+' || argv[1][0] == '-') |
Denis Vlasenko | 459903b | 2006-11-27 14:44:18 +0000 | [diff] [blame] | 115 | && isdigit(argv[1][1]) |
| 116 | ) { |
Denis Vlasenko | 3603cd2 | 2009-03-27 02:36:02 +0000 | [diff] [blame] | 117 | count = eat_num(argv[1]); |
Denis Vlasenko | 62a90cd | 2008-03-17 09:07:36 +0000 | [diff] [blame] | 118 | argv++; |
| 119 | argc--; |
Robert Griebl | 13c26fc | 2002-05-17 22:18:04 +0000 | [diff] [blame] | 120 | } |
Glenn L McGrath | 0bd0257 | 2005-12-11 03:09:05 +0000 | [diff] [blame] | 121 | #endif |
Robert Griebl | 13c26fc | 2002-05-17 22:18:04 +0000 | [diff] [blame] | 122 | |
Eric Lammerts | 3b5a664 | 2009-07-22 00:31:27 +0200 | [diff] [blame] | 123 | /* -s NUM, -F imlies -f */ |
Denys Vlasenko | 237bedd | 2016-07-06 21:58:02 +0200 | [diff] [blame] | 124 | IF_FEATURE_FANCY_TAIL(opt_complementary = "Ff";) |
| 125 | opt = getopt32(argv, "fc:n:" IF_FEATURE_FANCY_TAIL("qs:+vF"), |
Denis Vlasenko | 5e34ff2 | 2009-04-21 11:09:40 +0000 | [diff] [blame] | 126 | &str_c, &str_n IF_FEATURE_FANCY_TAIL(,&sleep_period)); |
Denis Vlasenko | e31f721 | 2006-12-22 16:06:16 +0000 | [diff] [blame] | 127 | #define FOLLOW (opt & 0x1) |
| 128 | #define COUNT_BYTES (opt & 0x2) |
| 129 | //if (opt & 0x1) // -f |
Bernhard Reutner-Fischer | 84d2d49 | 2007-01-24 21:38:10 +0000 | [diff] [blame] | 130 | if (opt & 0x2) count = eat_num(str_c); // -c |
| 131 | if (opt & 0x4) count = eat_num(str_n); // -n |
Bernhard Reutner-Fischer | 5816ccb | 2005-12-13 10:48:45 +0000 | [diff] [blame] | 132 | #if ENABLE_FEATURE_FANCY_TAIL |
Eric Lammerts | 3b5a664 | 2009-07-22 00:31:27 +0200 | [diff] [blame] | 133 | /* q: make it impossible for nfiles to be > header_threshhold */ |
| 134 | if (opt & 0x8) header_threshhold = UINT_MAX; // -q |
Denys Vlasenko | a43df64 | 2009-08-09 22:06:56 +0200 | [diff] [blame] | 135 | //if (opt & 0x10) // -s |
Denis Vlasenko | e31f721 | 2006-12-22 16:06:16 +0000 | [diff] [blame] | 136 | if (opt & 0x20) header_threshhold = 0; // -v |
Denys Vlasenko | a43df64 | 2009-08-09 22:06:56 +0200 | [diff] [blame] | 137 | # define FOLLOW_RETRY (opt & 0x40) |
Eric Lammerts | 3b5a664 | 2009-07-22 00:31:27 +0200 | [diff] [blame] | 138 | #else |
Denys Vlasenko | a43df64 | 2009-08-09 22:06:56 +0200 | [diff] [blame] | 139 | # define FOLLOW_RETRY 0 |
Matt Kraai | 55bccf3 | 2001-01-05 02:57:53 +0000 | [diff] [blame] | 140 | #endif |
Denis Vlasenko | 6910741 | 2006-12-21 00:43:06 +0000 | [diff] [blame] | 141 | argc -= optind; |
| 142 | argv += optind; |
Matt Kraai | 55bccf3 | 2001-01-05 02:57:53 +0000 | [diff] [blame] | 143 | |
| 144 | /* open all the files */ |
Eric Lammerts | 3b5a664 | 2009-07-22 00:31:27 +0200 | [diff] [blame] | 145 | fds = xmalloc(sizeof(fds[0]) * (argc + 1)); |
Denis Vlasenko | 62a90cd | 2008-03-17 09:07:36 +0000 | [diff] [blame] | 146 | if (!argv[0]) { |
Manuel Novoa III | cad5364 | 2003-03-19 09:13:01 +0000 | [diff] [blame] | 147 | struct stat statbuf; |
| 148 | |
Eric Lammerts | 3b5a664 | 2009-07-22 00:31:27 +0200 | [diff] [blame] | 149 | if (fstat(STDIN_FILENO, &statbuf) == 0 |
| 150 | && S_ISFIFO(statbuf.st_mode) |
| 151 | ) { |
Denis Vlasenko | e31f721 | 2006-12-22 16:06:16 +0000 | [diff] [blame] | 152 | opt &= ~1; /* clear FOLLOW */ |
Matt Kraai | 55bccf3 | 2001-01-05 02:57:53 +0000 | [diff] [blame] | 153 | } |
Eric Lammerts | 3b5a664 | 2009-07-22 00:31:27 +0200 | [diff] [blame] | 154 | argv[0] = (char *) bb_msg_standard_input; |
Matt Kraai | 55bccf3 | 2001-01-05 02:57:53 +0000 | [diff] [blame] | 155 | } |
Denis Vlasenko | 62a90cd | 2008-03-17 09:07:36 +0000 | [diff] [blame] | 156 | nfiles = i = 0; |
Manuel Novoa III | cad5364 | 2003-03-19 09:13:01 +0000 | [diff] [blame] | 157 | do { |
Denis Vlasenko | 62a90cd | 2008-03-17 09:07:36 +0000 | [diff] [blame] | 158 | int fd = open_or_warn_stdin(argv[i]); |
Eric Lammerts | 3b5a664 | 2009-07-22 00:31:27 +0200 | [diff] [blame] | 159 | if (fd < 0 && !FOLLOW_RETRY) { |
Denys Vlasenko | 9e933d9 | 2011-05-20 00:30:04 +0200 | [diff] [blame] | 160 | G.exitcode = EXIT_FAILURE; |
Bernhard Reutner-Fischer | d9c2d5f | 2007-04-04 20:29:15 +0000 | [diff] [blame] | 161 | continue; |
Manuel Novoa III | cad5364 | 2003-03-19 09:13:01 +0000 | [diff] [blame] | 162 | } |
Denis Vlasenko | 62a90cd | 2008-03-17 09:07:36 +0000 | [diff] [blame] | 163 | fds[nfiles] = fd; |
Bernhard Reutner-Fischer | d9c2d5f | 2007-04-04 20:29:15 +0000 | [diff] [blame] | 164 | argv[nfiles++] = argv[i]; |
Manuel Novoa III | cad5364 | 2003-03-19 09:13:01 +0000 | [diff] [blame] | 165 | } while (++i < argc); |
| 166 | |
Denis Vlasenko | e31f721 | 2006-12-22 16:06:16 +0000 | [diff] [blame] | 167 | if (!nfiles) |
Manuel Novoa III | cad5364 | 2003-03-19 09:13:01 +0000 | [diff] [blame] | 168 | bb_error_msg_and_die("no files"); |
Manuel Novoa III | cad5364 | 2003-03-19 09:13:01 +0000 | [diff] [blame] | 169 | |
Denis Vlasenko | e8419c9 | 2008-02-19 00:38:10 +0000 | [diff] [blame] | 170 | /* prepare the buffer */ |
Manuel Novoa III | cad5364 | 2003-03-19 09:13:01 +0000 | [diff] [blame] | 171 | tailbufsize = BUFSIZ; |
Denys Vlasenko | 9e933d9 | 2011-05-20 00:30:04 +0200 | [diff] [blame] | 172 | if (!G.from_top && COUNT_BYTES) { |
Denis Vlasenko | e8419c9 | 2008-02-19 00:38:10 +0000 | [diff] [blame] | 173 | if (tailbufsize < count + BUFSIZ) { |
Manuel Novoa III | cad5364 | 2003-03-19 09:13:01 +0000 | [diff] [blame] | 174 | tailbufsize = count + BUFSIZ; |
| 175 | } |
| 176 | } |
Denys Vlasenko | 9e933d9 | 2011-05-20 00:30:04 +0200 | [diff] [blame] | 177 | /* tail -c1024m REGULAR_FILE doesn't really need 1G mem block. |
| 178 | * (In fact, it doesn't need ANY memory). So delay allocation. |
| 179 | */ |
| 180 | tailbuf = NULL; |
Glenn L McGrath | 4ef5a84 | 2003-10-31 00:35:59 +0000 | [diff] [blame] | 181 | |
Denis Vlasenko | e8419c9 | 2008-02-19 00:38:10 +0000 | [diff] [blame] | 182 | /* tail the files */ |
Denys Vlasenko | 9e933d9 | 2011-05-20 00:30:04 +0200 | [diff] [blame] | 183 | |
| 184 | fmt = header_fmt_str + 1; /* skip leading newline in the header on the first output */ |
Manuel Novoa III | cad5364 | 2003-03-19 09:13:01 +0000 | [diff] [blame] | 185 | i = 0; |
| 186 | do { |
Eric Lammerts | 3b5a664 | 2009-07-22 00:31:27 +0200 | [diff] [blame] | 187 | char *buf; |
| 188 | int taillen; |
| 189 | int newlines_seen; |
| 190 | unsigned seen; |
| 191 | int nread; |
Denys Vlasenko | 79b021d | 2009-08-10 03:16:18 +0200 | [diff] [blame] | 192 | int fd = fds[i]; |
Eric Lammerts | 3b5a664 | 2009-07-22 00:31:27 +0200 | [diff] [blame] | 193 | |
Denys Vlasenko | 79b021d | 2009-08-10 03:16:18 +0200 | [diff] [blame] | 194 | if (ENABLE_FEATURE_FANCY_TAIL && fd < 0) |
Denys Vlasenko | 0851d12 | 2011-09-17 00:12:24 +0200 | [diff] [blame] | 195 | continue; /* may happen with -F */ |
Eric Lammerts | 3b5a664 | 2009-07-22 00:31:27 +0200 | [diff] [blame] | 196 | |
Manuel Novoa III | cad5364 | 2003-03-19 09:13:01 +0000 | [diff] [blame] | 197 | if (nfiles > header_threshhold) { |
| 198 | tail_xprint_header(fmt, argv[i]); |
Denys Vlasenko | ea8b252 | 2010-06-02 12:57:26 +0200 | [diff] [blame] | 199 | fmt = header_fmt_str; |
Manuel Novoa III | cad5364 | 2003-03-19 09:13:01 +0000 | [diff] [blame] | 200 | } |
| 201 | |
Denys Vlasenko | 9e933d9 | 2011-05-20 00:30:04 +0200 | [diff] [blame] | 202 | if (!G.from_top) { |
Denys Vlasenko | 79b021d | 2009-08-10 03:16:18 +0200 | [diff] [blame] | 203 | off_t current = lseek(fd, 0, SEEK_END); |
Denis Vlasenko | 69ca5a7 | 2008-03-23 03:28:40 +0000 | [diff] [blame] | 204 | if (current > 0) { |
Denys Vlasenko | 79b021d | 2009-08-10 03:16:18 +0200 | [diff] [blame] | 205 | unsigned off; |
| 206 | if (COUNT_BYTES) { |
| 207 | /* Optimizing count-bytes case if the file is seekable. |
| 208 | * Beware of backing up too far. |
| 209 | * Also we exclude files with size 0 (because of /proc/xxx) */ |
| 210 | if (count == 0) |
| 211 | continue; /* showing zero bytes is easy :) */ |
| 212 | current -= count; |
| 213 | if (current < 0) |
| 214 | current = 0; |
| 215 | xlseek(fd, current, SEEK_SET); |
| 216 | bb_copyfd_size(fd, STDOUT_FILENO, count); |
| 217 | continue; |
| 218 | } |
| 219 | #if 1 /* This is technically incorrect for *LONG* strings, but very useful */ |
| 220 | /* Optimizing count-lines case if the file is seekable. |
| 221 | * We assume the lines are <64k. |
| 222 | * (Users complain that tail takes too long |
| 223 | * on multi-gigabyte files) */ |
| 224 | off = (count | 0xf); /* for small counts, be more paranoid */ |
| 225 | if (off > (INT_MAX / (64*1024))) |
| 226 | off = (INT_MAX / (64*1024)); |
| 227 | current -= off * (64*1024); |
Denis Vlasenko | 69ca5a7 | 2008-03-23 03:28:40 +0000 | [diff] [blame] | 228 | if (current < 0) |
| 229 | current = 0; |
Denys Vlasenko | 79b021d | 2009-08-10 03:16:18 +0200 | [diff] [blame] | 230 | xlseek(fd, current, SEEK_SET); |
| 231 | #endif |
Denis Vlasenko | e8419c9 | 2008-02-19 00:38:10 +0000 | [diff] [blame] | 232 | } |
| 233 | } |
| 234 | |
Denys Vlasenko | 9e933d9 | 2011-05-20 00:30:04 +0200 | [diff] [blame] | 235 | if (!tailbuf) |
| 236 | tailbuf = xmalloc(tailbufsize); |
| 237 | |
Manuel Novoa III | cad5364 | 2003-03-19 09:13:01 +0000 | [diff] [blame] | 238 | buf = tailbuf; |
| 239 | taillen = 0; |
Denys Vlasenko | a43df64 | 2009-08-09 22:06:56 +0200 | [diff] [blame] | 240 | /* "We saw 1st line/byte". |
Denys Vlasenko | 79b021d | 2009-08-10 03:16:18 +0200 | [diff] [blame] | 241 | * Used only by +N code ("start from Nth", 1-based): */ |
Manuel Novoa III | cad5364 | 2003-03-19 09:13:01 +0000 | [diff] [blame] | 242 | seen = 1; |
Denis Vlasenko | e8419c9 | 2008-02-19 00:38:10 +0000 | [diff] [blame] | 243 | newlines_seen = 0; |
Denys Vlasenko | d87fcd4 | 2013-07-08 02:39:51 +0200 | [diff] [blame] | 244 | while ((nread = tail_read(fd, buf, tailbufsize - taillen)) > 0) { |
Denys Vlasenko | 9e933d9 | 2011-05-20 00:30:04 +0200 | [diff] [blame] | 245 | if (G.from_top) { |
Eric Lammerts | 3b5a664 | 2009-07-22 00:31:27 +0200 | [diff] [blame] | 246 | int nwrite = nread; |
Manuel Novoa III | cad5364 | 2003-03-19 09:13:01 +0000 | [diff] [blame] | 247 | if (seen < count) { |
Denys Vlasenko | a43df64 | 2009-08-09 22:06:56 +0200 | [diff] [blame] | 248 | /* We need to skip a few more bytes/lines */ |
Denis Vlasenko | e31f721 | 2006-12-22 16:06:16 +0000 | [diff] [blame] | 249 | if (COUNT_BYTES) { |
Manuel Novoa III | cad5364 | 2003-03-19 09:13:01 +0000 | [diff] [blame] | 250 | nwrite -= (count - seen); |
Denys Vlasenko | 0851d12 | 2011-09-17 00:12:24 +0200 | [diff] [blame] | 251 | seen += nread; |
Glenn L McGrath | 4ef5a84 | 2003-10-31 00:35:59 +0000 | [diff] [blame] | 252 | } else { |
Eric Lammerts | 3b5a664 | 2009-07-22 00:31:27 +0200 | [diff] [blame] | 253 | char *s = buf; |
Manuel Novoa III | cad5364 | 2003-03-19 09:13:01 +0000 | [diff] [blame] | 254 | do { |
| 255 | --nwrite; |
Denis Vlasenko | e31f721 | 2006-12-22 16:06:16 +0000 | [diff] [blame] | 256 | if (*s++ == '\n' && ++seen == count) { |
Matt Kraai | 55bccf3 | 2001-01-05 02:57:53 +0000 | [diff] [blame] | 257 | break; |
| 258 | } |
Manuel Novoa III | cad5364 | 2003-03-19 09:13:01 +0000 | [diff] [blame] | 259 | } while (nwrite); |
| 260 | } |
| 261 | } |
Denys Vlasenko | 6eaeb77 | 2010-03-12 22:16:25 +0100 | [diff] [blame] | 262 | if (nwrite > 0) |
| 263 | xwrite(STDOUT_FILENO, buf + nread - nwrite, nwrite); |
Manuel Novoa III | cad5364 | 2003-03-19 09:13:01 +0000 | [diff] [blame] | 264 | } else if (count) { |
Denis Vlasenko | e31f721 | 2006-12-22 16:06:16 +0000 | [diff] [blame] | 265 | if (COUNT_BYTES) { |
Manuel Novoa III | cad5364 | 2003-03-19 09:13:01 +0000 | [diff] [blame] | 266 | taillen += nread; |
Denis Vlasenko | 77ad97f | 2008-05-13 02:27:31 +0000 | [diff] [blame] | 267 | if (taillen > (int)count) { |
Manuel Novoa III | cad5364 | 2003-03-19 09:13:01 +0000 | [diff] [blame] | 268 | memmove(tailbuf, tailbuf + taillen - count, count); |
| 269 | taillen = count; |
| 270 | } |
Glenn L McGrath | 4ef5a84 | 2003-10-31 00:35:59 +0000 | [diff] [blame] | 271 | } else { |
Manuel Novoa III | cad5364 | 2003-03-19 09:13:01 +0000 | [diff] [blame] | 272 | int k = nread; |
Denis Vlasenko | e8419c9 | 2008-02-19 00:38:10 +0000 | [diff] [blame] | 273 | int newlines_in_buf = 0; |
Manuel Novoa III | cad5364 | 2003-03-19 09:13:01 +0000 | [diff] [blame] | 274 | |
Denis Vlasenko | e8419c9 | 2008-02-19 00:38:10 +0000 | [diff] [blame] | 275 | do { /* count '\n' in last read */ |
| 276 | k--; |
Manuel Novoa III | cad5364 | 2003-03-19 09:13:01 +0000 | [diff] [blame] | 277 | if (buf[k] == '\n') { |
Denis Vlasenko | e8419c9 | 2008-02-19 00:38:10 +0000 | [diff] [blame] | 278 | newlines_in_buf++; |
Matt Kraai | 55bccf3 | 2001-01-05 02:57:53 +0000 | [diff] [blame] | 279 | } |
Denis Vlasenko | e8419c9 | 2008-02-19 00:38:10 +0000 | [diff] [blame] | 280 | } while (k); |
Manuel Novoa III | cad5364 | 2003-03-19 09:13:01 +0000 | [diff] [blame] | 281 | |
Denis Vlasenko | 77ad97f | 2008-05-13 02:27:31 +0000 | [diff] [blame] | 282 | if (newlines_seen + newlines_in_buf < (int)count) { |
Denis Vlasenko | e8419c9 | 2008-02-19 00:38:10 +0000 | [diff] [blame] | 283 | newlines_seen += newlines_in_buf; |
Manuel Novoa III | cad5364 | 2003-03-19 09:13:01 +0000 | [diff] [blame] | 284 | taillen += nread; |
Matt Kraai | 55bccf3 | 2001-01-05 02:57:53 +0000 | [diff] [blame] | 285 | } else { |
Denis Vlasenko | e8419c9 | 2008-02-19 00:38:10 +0000 | [diff] [blame] | 286 | int extra = (buf[nread-1] != '\n'); |
Eric Lammerts | 3b5a664 | 2009-07-22 00:31:27 +0200 | [diff] [blame] | 287 | char *s; |
Manuel Novoa III | cad5364 | 2003-03-19 09:13:01 +0000 | [diff] [blame] | 288 | |
Denis Vlasenko | e8419c9 | 2008-02-19 00:38:10 +0000 | [diff] [blame] | 289 | k = newlines_seen + newlines_in_buf + extra - count; |
Manuel Novoa III | cad5364 | 2003-03-19 09:13:01 +0000 | [diff] [blame] | 290 | s = tailbuf; |
| 291 | while (k) { |
| 292 | if (*s == '\n') { |
Denis Vlasenko | e8419c9 | 2008-02-19 00:38:10 +0000 | [diff] [blame] | 293 | k--; |
Manuel Novoa III | cad5364 | 2003-03-19 09:13:01 +0000 | [diff] [blame] | 294 | } |
Denis Vlasenko | e8419c9 | 2008-02-19 00:38:10 +0000 | [diff] [blame] | 295 | s++; |
Manuel Novoa III | cad5364 | 2003-03-19 09:13:01 +0000 | [diff] [blame] | 296 | } |
Manuel Novoa III | cad5364 | 2003-03-19 09:13:01 +0000 | [diff] [blame] | 297 | taillen += nread - (s - tailbuf); |
| 298 | memmove(tailbuf, s, taillen); |
Denis Vlasenko | e8419c9 | 2008-02-19 00:38:10 +0000 | [diff] [blame] | 299 | newlines_seen = count - extra; |
Matt Kraai | 55bccf3 | 2001-01-05 02:57:53 +0000 | [diff] [blame] | 300 | } |
Denis Vlasenko | 77ad97f | 2008-05-13 02:27:31 +0000 | [diff] [blame] | 301 | if (tailbufsize < (size_t)taillen + BUFSIZ) { |
Manuel Novoa III | cad5364 | 2003-03-19 09:13:01 +0000 | [diff] [blame] | 302 | tailbufsize = taillen + BUFSIZ; |
| 303 | tailbuf = xrealloc(tailbuf, tailbufsize); |
Matt Kraai | 55bccf3 | 2001-01-05 02:57:53 +0000 | [diff] [blame] | 304 | } |
Eric Andersen | d5fa3e3 | 2000-08-02 16:42:58 +0000 | [diff] [blame] | 305 | } |
Manuel Novoa III | cad5364 | 2003-03-19 09:13:01 +0000 | [diff] [blame] | 306 | buf = tailbuf + taillen; |
Eric Andersen | d5fa3e3 | 2000-08-02 16:42:58 +0000 | [diff] [blame] | 307 | } |
Denis Vlasenko | e8419c9 | 2008-02-19 00:38:10 +0000 | [diff] [blame] | 308 | } /* while (tail_read() > 0) */ |
Denys Vlasenko | 9e933d9 | 2011-05-20 00:30:04 +0200 | [diff] [blame] | 309 | if (!G.from_top) { |
Denis Vlasenko | e31f721 | 2006-12-22 16:06:16 +0000 | [diff] [blame] | 310 | xwrite(STDOUT_FILENO, tailbuf, taillen); |
Matt Kraai | 55bccf3 | 2001-01-05 02:57:53 +0000 | [diff] [blame] | 311 | } |
Manuel Novoa III | cad5364 | 2003-03-19 09:13:01 +0000 | [diff] [blame] | 312 | } while (++i < nfiles); |
Bartosz Golaszewski | 6493801 | 2013-10-14 20:11:55 +0200 | [diff] [blame] | 313 | prev_fd = fds[i-1]; |
Manuel Novoa III | cad5364 | 2003-03-19 09:13:01 +0000 | [diff] [blame] | 314 | |
Eric Lammerts | 3b5a664 | 2009-07-22 00:31:27 +0200 | [diff] [blame] | 315 | tailbuf = xrealloc(tailbuf, BUFSIZ); |
Manuel Novoa III | cad5364 | 2003-03-19 09:13:01 +0000 | [diff] [blame] | 316 | |
| 317 | fmt = NULL; |
Matt Kraai | 55bccf3 | 2001-01-05 02:57:53 +0000 | [diff] [blame] | 318 | |
Denis Vlasenko | e31f721 | 2006-12-22 16:06:16 +0000 | [diff] [blame] | 319 | if (FOLLOW) while (1) { |
Matt Kraai | 55bccf3 | 2001-01-05 02:57:53 +0000 | [diff] [blame] | 320 | sleep(sleep_period); |
Eric Lammerts | 3b5a664 | 2009-07-22 00:31:27 +0200 | [diff] [blame] | 321 | |
Manuel Novoa III | cad5364 | 2003-03-19 09:13:01 +0000 | [diff] [blame] | 322 | i = 0; |
| 323 | do { |
Eric Lammerts | 3b5a664 | 2009-07-22 00:31:27 +0200 | [diff] [blame] | 324 | int nread; |
| 325 | const char *filename = argv[i]; |
| 326 | int fd = fds[i]; |
| 327 | |
| 328 | if (FOLLOW_RETRY) { |
| 329 | struct stat sbuf, fsbuf; |
| 330 | |
| 331 | if (fd < 0 |
| 332 | || fstat(fd, &fsbuf) < 0 |
| 333 | || stat(filename, &sbuf) < 0 |
| 334 | || fsbuf.st_dev != sbuf.st_dev |
| 335 | || fsbuf.st_ino != sbuf.st_ino |
| 336 | ) { |
| 337 | int new_fd; |
| 338 | |
| 339 | if (fd >= 0) |
| 340 | close(fd); |
| 341 | new_fd = open(filename, O_RDONLY); |
| 342 | if (new_fd >= 0) { |
| 343 | bb_error_msg("%s has %s; following end of new file", |
| 344 | filename, (fd < 0) ? "appeared" : "been replaced" |
| 345 | ); |
| 346 | } else if (fd >= 0) { |
| 347 | bb_perror_msg("%s has become inaccessible", filename); |
| 348 | } |
| 349 | fds[i] = fd = new_fd; |
| 350 | } |
| 351 | } |
| 352 | if (ENABLE_FEATURE_FANCY_TAIL && fd < 0) |
| 353 | continue; |
Manuel Novoa III | cad5364 | 2003-03-19 09:13:01 +0000 | [diff] [blame] | 354 | if (nfiles > header_threshhold) { |
Denys Vlasenko | ea8b252 | 2010-06-02 12:57:26 +0200 | [diff] [blame] | 355 | fmt = header_fmt_str; |
Matt Kraai | 55bccf3 | 2001-01-05 02:57:53 +0000 | [diff] [blame] | 356 | } |
Denys Vlasenko | d87fcd4 | 2013-07-08 02:39:51 +0200 | [diff] [blame] | 357 | for (;;) { |
| 358 | /* tail -f keeps following files even if they are truncated */ |
| 359 | struct stat sbuf; |
| 360 | /* /proc files report zero st_size, don't lseek them */ |
| 361 | if (fstat(fd, &sbuf) == 0 && sbuf.st_size > 0) { |
| 362 | off_t current = lseek(fd, 0, SEEK_CUR); |
| 363 | if (sbuf.st_size < current) |
| 364 | xlseek(fd, 0, SEEK_SET); |
| 365 | } |
| 366 | |
| 367 | nread = tail_read(fd, tailbuf, BUFSIZ); |
| 368 | if (nread <= 0) |
| 369 | break; |
Bartosz Golaszewski | 6493801 | 2013-10-14 20:11:55 +0200 | [diff] [blame] | 370 | if (fmt && (fd != prev_fd)) { |
Eric Lammerts | 3b5a664 | 2009-07-22 00:31:27 +0200 | [diff] [blame] | 371 | tail_xprint_header(fmt, filename); |
Manuel Novoa III | cad5364 | 2003-03-19 09:13:01 +0000 | [diff] [blame] | 372 | fmt = NULL; |
Bartosz Golaszewski | 6493801 | 2013-10-14 20:11:55 +0200 | [diff] [blame] | 373 | prev_fd = fd; |
Manuel Novoa III | cad5364 | 2003-03-19 09:13:01 +0000 | [diff] [blame] | 374 | } |
Eric Lammerts | 3b5a664 | 2009-07-22 00:31:27 +0200 | [diff] [blame] | 375 | xwrite(STDOUT_FILENO, tailbuf, nread); |
Matt Kraai | 55bccf3 | 2001-01-05 02:57:53 +0000 | [diff] [blame] | 376 | } |
Manuel Novoa III | cad5364 | 2003-03-19 09:13:01 +0000 | [diff] [blame] | 377 | } while (++i < nfiles); |
Denys Vlasenko | 9e933d9 | 2011-05-20 00:30:04 +0200 | [diff] [blame] | 378 | } /* while (1) */ |
| 379 | |
Bernhard Reutner-Fischer | d9c2d5f | 2007-04-04 20:29:15 +0000 | [diff] [blame] | 380 | if (ENABLE_FEATURE_CLEAN_UP) { |
| 381 | free(fds); |
Alexander Shishkin | 2348e09 | 2010-10-21 00:25:45 +0200 | [diff] [blame] | 382 | free(tailbuf); |
Bernhard Reutner-Fischer | d9c2d5f | 2007-04-04 20:29:15 +0000 | [diff] [blame] | 383 | } |
Denys Vlasenko | 9e933d9 | 2011-05-20 00:30:04 +0200 | [diff] [blame] | 384 | return G.exitcode; |
Matt Kraai | 55bccf3 | 2001-01-05 02:57:53 +0000 | [diff] [blame] | 385 | } |