Erik Andersen | e49d5ec | 2000-02-08 19:58:47 +0000 | [diff] [blame] | 1 | /* vi: set sw=4 ts=4: */ |
Erik Andersen | 3fe39dc | 2000-01-25 18:13:53 +0000 | [diff] [blame] | 2 | #include "internal.h" |
| 3 | /* This file contains _two_ implementations of tail. One is |
| 4 | * a bit more full featured, but costs 6k. The other (i.e. the |
| 5 | * SIMPLE_TAIL one) is less capable, but is good enough for about |
| 6 | * 99% of the things folks want to use tail for, and only costs 2k. |
| 7 | */ |
| 8 | |
| 9 | |
| 10 | #ifdef BB_FEATURE_SIMPLE_TAIL |
| 11 | |
| 12 | /* tail -- output the last part of file(s) |
| 13 | Copyright (C) 89, 90, 91, 95, 1996 Free Software Foundation, Inc. |
| 14 | |
| 15 | This program is free software; you can redistribute it and/or modify |
| 16 | it under the terms of the GNU General Public License as published by |
| 17 | the Free Software Foundation; either version 2, or (at your option) |
| 18 | any later version. |
| 19 | |
| 20 | This program is distributed in the hope that it will be useful, |
| 21 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 22 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 23 | GNU General Public License for more details. |
| 24 | |
| 25 | You should have received a copy of the GNU General Public License |
| 26 | along with this program; if not, write to the Free Software |
| 27 | Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. |
| 28 | |
| 29 | Original version by Paul Rubin <phr@ocf.berkeley.edu>. |
| 30 | Extensions by David MacKenzie <djm@gnu.ai.mit.edu>. |
| 31 | tail -f for multiple files by Ian Lance Taylor <ian@airs.com>. |
| 32 | |
| 33 | Rewrote the option parser, removed locales support, |
| 34 | and generally busyboxed, Erik Andersen <andersen@lineo.com> |
| 35 | |
| 36 | Removed superfluous options and associated code ("-c", "-n", "-q"). |
Erik Andersen | fac10d7 | 2000-02-07 05:29:42 +0000 | [diff] [blame] | 37 | Removed "tail -f" support for multiple files. |
Erik Andersen | 3fe39dc | 2000-01-25 18:13:53 +0000 | [diff] [blame] | 38 | Both changes by Friedrich Vedder <fwv@myrtle.lahn.de>. |
| 39 | |
| 40 | */ |
| 41 | |
| 42 | |
| 43 | #include <stdio.h> |
| 44 | #include <stdarg.h> |
| 45 | #include <sys/types.h> |
| 46 | #include <sys/stat.h> |
| 47 | #include <fcntl.h> |
| 48 | #include <ctype.h> |
| 49 | |
| 50 | |
| 51 | #define XWRITE(fd, buffer, n_bytes) \ |
| 52 | do { \ |
| 53 | if (n_bytes > 0 && fwrite ((buffer), 1, (n_bytes), stdout) == 0) \ |
| 54 | error("write error"); \ |
| 55 | } while (0) |
| 56 | |
| 57 | /* Number of items to tail. */ |
| 58 | #define DEFAULT_N_LINES 10 |
| 59 | |
| 60 | /* Size of atomic reads. */ |
| 61 | #ifndef BUFSIZ |
| 62 | #define BUFSIZ (512 * 8) |
| 63 | #endif |
| 64 | |
| 65 | /* If nonzero, read from the end of one file until killed. */ |
| 66 | static int forever; |
| 67 | |
| 68 | /* If nonzero, print filename headers. */ |
| 69 | static int print_headers; |
| 70 | |
| 71 | const char tail_usage[] = |
Erik Andersen | e49d5ec | 2000-02-08 19:58:47 +0000 | [diff] [blame] | 72 | "tail [OPTION] [FILE]...\n\n" |
| 73 | "Print last 10 lines of each FILE to standard output.\n" |
| 74 | "With more than one FILE, precede each with a header giving the\n" |
| 75 | "file name. With no FILE, or when FILE is -, read standard input.\n\n" |
| 76 | "Options:\n" |
| 77 | "\t-n NUM\t\tPrint last NUM lines instead of first 10\n" |
| 78 | |
| 79 | "\t-f\t\tOutput data as the file grows. This version\n" |
| 80 | "\t\t\tof 'tail -f' supports only one file at a time.\n"; |
Erik Andersen | 3fe39dc | 2000-01-25 18:13:53 +0000 | [diff] [blame] | 81 | |
| 82 | |
| 83 | static void write_header(const char *filename) |
| 84 | { |
Erik Andersen | e49d5ec | 2000-02-08 19:58:47 +0000 | [diff] [blame] | 85 | static int first_file = 1; |
Erik Andersen | 3fe39dc | 2000-01-25 18:13:53 +0000 | [diff] [blame] | 86 | |
Erik Andersen | e49d5ec | 2000-02-08 19:58:47 +0000 | [diff] [blame] | 87 | printf("%s==> %s <==\n", (first_file ? "" : "\n"), filename); |
| 88 | first_file = 0; |
Erik Andersen | 3fe39dc | 2000-01-25 18:13:53 +0000 | [diff] [blame] | 89 | } |
| 90 | |
| 91 | /* Print the last N_LINES lines from the end of file FD. |
| 92 | Go backward through the file, reading `BUFSIZ' bytes at a time (except |
| 93 | probably the first), until we hit the start of the file or have |
| 94 | read NUMBER newlines. |
| 95 | POS starts out as the length of the file (the offset of the last |
| 96 | byte of the file + 1). |
| 97 | Return 0 if successful, 1 if an error occurred. */ |
| 98 | |
| 99 | static int |
| 100 | file_lines(const char *filename, int fd, long int n_lines, off_t pos) |
| 101 | { |
Erik Andersen | e49d5ec | 2000-02-08 19:58:47 +0000 | [diff] [blame] | 102 | char buffer[BUFSIZ]; |
| 103 | int bytes_read; |
| 104 | int i; /* Index into `buffer' for scanning. */ |
Erik Andersen | 3fe39dc | 2000-01-25 18:13:53 +0000 | [diff] [blame] | 105 | |
Erik Andersen | e49d5ec | 2000-02-08 19:58:47 +0000 | [diff] [blame] | 106 | if (n_lines == 0) |
Erik Andersen | 3fe39dc | 2000-01-25 18:13:53 +0000 | [diff] [blame] | 107 | return 0; |
Erik Andersen | 3fe39dc | 2000-01-25 18:13:53 +0000 | [diff] [blame] | 108 | |
Erik Andersen | e49d5ec | 2000-02-08 19:58:47 +0000 | [diff] [blame] | 109 | /* Set `bytes_read' to the size of the last, probably partial, buffer; |
| 110 | 0 < `bytes_read' <= `BUFSIZ'. */ |
| 111 | bytes_read = pos % BUFSIZ; |
| 112 | if (bytes_read == 0) |
| 113 | bytes_read = BUFSIZ; |
| 114 | /* Make `pos' a multiple of `BUFSIZ' (0 if the file is short), so that all |
| 115 | reads will be on block boundaries, which might increase efficiency. */ |
| 116 | pos -= bytes_read; |
| 117 | lseek(fd, pos, SEEK_SET); |
| 118 | bytes_read = fullRead(fd, buffer, bytes_read); |
| 119 | if (bytes_read == -1) |
| 120 | error("read error"); |
| 121 | |
| 122 | /* Count the incomplete line on files that don't end with a newline. */ |
| 123 | if (bytes_read && buffer[bytes_read - 1] != '\n') |
| 124 | --n_lines; |
| 125 | |
| 126 | do { |
| 127 | /* Scan backward, counting the newlines in this bufferfull. */ |
| 128 | for (i = bytes_read - 1; i >= 0; i--) { |
| 129 | /* Have we counted the requested number of newlines yet? */ |
| 130 | if (buffer[i] == '\n' && n_lines-- == 0) { |
| 131 | /* If this newline wasn't the last character in the buffer, |
| 132 | print the text after it. */ |
| 133 | if (i != bytes_read - 1) |
| 134 | XWRITE(STDOUT_FILENO, &buffer[i + 1], |
| 135 | bytes_read - (i + 1)); |
| 136 | return 0; |
| 137 | } |
| 138 | } |
| 139 | /* Not enough newlines in that bufferfull. */ |
| 140 | if (pos == 0) { |
| 141 | /* Not enough lines in the file; print the entire file. */ |
| 142 | lseek(fd, (off_t) 0, SEEK_SET); |
| 143 | return 0; |
| 144 | } |
| 145 | pos -= BUFSIZ; |
| 146 | lseek(fd, pos, SEEK_SET); |
| 147 | } |
| 148 | while ((bytes_read = fullRead(fd, buffer, BUFSIZ)) > 0); |
| 149 | if (bytes_read == -1) |
| 150 | error("read error"); |
| 151 | |
| 152 | return 0; |
Erik Andersen | 3fe39dc | 2000-01-25 18:13:53 +0000 | [diff] [blame] | 153 | } |
| 154 | |
| 155 | /* Print the last N_LINES lines from the end of the standard input, |
| 156 | open for reading as pipe FD. |
| 157 | Buffer the text as a linked list of LBUFFERs, adding them as needed. |
| 158 | Return 0 if successful, 1 if an error occured. */ |
| 159 | |
| 160 | static int pipe_lines(const char *filename, int fd, long int n_lines) |
| 161 | { |
Erik Andersen | e49d5ec | 2000-02-08 19:58:47 +0000 | [diff] [blame] | 162 | struct linebuffer { |
| 163 | int nbytes, nlines; |
| 164 | char buffer[BUFSIZ]; |
| 165 | struct linebuffer *next; |
| 166 | }; |
| 167 | typedef struct linebuffer LBUFFER; |
| 168 | LBUFFER *first, *last, *tmp; |
| 169 | int i; /* Index into buffers. */ |
| 170 | int total_lines = 0; /* Total number of newlines in all buffers. */ |
| 171 | int errors = 0; |
Erik Andersen | 3fe39dc | 2000-01-25 18:13:53 +0000 | [diff] [blame] | 172 | |
Erik Andersen | e49d5ec | 2000-02-08 19:58:47 +0000 | [diff] [blame] | 173 | first = last = (LBUFFER *) xmalloc(sizeof(LBUFFER)); |
| 174 | first->nbytes = first->nlines = 0; |
| 175 | first->next = NULL; |
| 176 | tmp = (LBUFFER *) xmalloc(sizeof(LBUFFER)); |
Erik Andersen | 3fe39dc | 2000-01-25 18:13:53 +0000 | [diff] [blame] | 177 | |
Erik Andersen | e49d5ec | 2000-02-08 19:58:47 +0000 | [diff] [blame] | 178 | /* Input is always read into a fresh buffer. */ |
| 179 | while ((tmp->nbytes = fullRead(fd, tmp->buffer, BUFSIZ)) > 0) { |
| 180 | tmp->nlines = 0; |
| 181 | tmp->next = NULL; |
Erik Andersen | 3fe39dc | 2000-01-25 18:13:53 +0000 | [diff] [blame] | 182 | |
Erik Andersen | e49d5ec | 2000-02-08 19:58:47 +0000 | [diff] [blame] | 183 | /* Count the number of newlines just read. */ |
| 184 | for (i = 0; i < tmp->nbytes; i++) |
| 185 | if (tmp->buffer[i] == '\n') |
| 186 | ++tmp->nlines; |
| 187 | total_lines += tmp->nlines; |
Erik Andersen | 3fe39dc | 2000-01-25 18:13:53 +0000 | [diff] [blame] | 188 | |
Erik Andersen | e49d5ec | 2000-02-08 19:58:47 +0000 | [diff] [blame] | 189 | /* If there is enough room in the last buffer read, just append the new |
| 190 | one to it. This is because when reading from a pipe, `nbytes' can |
| 191 | often be very small. */ |
| 192 | if (tmp->nbytes + last->nbytes < BUFSIZ) { |
| 193 | memcpy(&last->buffer[last->nbytes], tmp->buffer, tmp->nbytes); |
| 194 | last->nbytes += tmp->nbytes; |
| 195 | last->nlines += tmp->nlines; |
| 196 | } else { |
| 197 | /* If there's not enough room, link the new buffer onto the end of |
| 198 | the list, then either free up the oldest buffer for the next |
| 199 | read if that would leave enough lines, or else malloc a new one. |
| 200 | Some compaction mechanism is possible but probably not |
| 201 | worthwhile. */ |
| 202 | last = last->next = tmp; |
| 203 | if (total_lines - first->nlines > n_lines) { |
| 204 | tmp = first; |
| 205 | total_lines -= first->nlines; |
| 206 | first = first->next; |
| 207 | } else |
| 208 | tmp = (LBUFFER *) xmalloc(sizeof(LBUFFER)); |
| 209 | } |
Erik Andersen | 3fe39dc | 2000-01-25 18:13:53 +0000 | [diff] [blame] | 210 | } |
Erik Andersen | e49d5ec | 2000-02-08 19:58:47 +0000 | [diff] [blame] | 211 | if (tmp->nbytes == -1) |
| 212 | error("read error"); |
Erik Andersen | 3fe39dc | 2000-01-25 18:13:53 +0000 | [diff] [blame] | 213 | |
Erik Andersen | e49d5ec | 2000-02-08 19:58:47 +0000 | [diff] [blame] | 214 | free((char *) tmp); |
Erik Andersen | 3fe39dc | 2000-01-25 18:13:53 +0000 | [diff] [blame] | 215 | |
Erik Andersen | e49d5ec | 2000-02-08 19:58:47 +0000 | [diff] [blame] | 216 | /* This prevents a core dump when the pipe contains no newlines. */ |
| 217 | if (n_lines == 0) |
| 218 | goto free_lbuffers; |
Erik Andersen | 3fe39dc | 2000-01-25 18:13:53 +0000 | [diff] [blame] | 219 | |
Erik Andersen | e49d5ec | 2000-02-08 19:58:47 +0000 | [diff] [blame] | 220 | /* Count the incomplete line on files that don't end with a newline. */ |
| 221 | if (last->buffer[last->nbytes - 1] != '\n') { |
| 222 | ++last->nlines; |
| 223 | ++total_lines; |
| 224 | } |
Erik Andersen | 3fe39dc | 2000-01-25 18:13:53 +0000 | [diff] [blame] | 225 | |
Erik Andersen | e49d5ec | 2000-02-08 19:58:47 +0000 | [diff] [blame] | 226 | /* Run through the list, printing lines. First, skip over unneeded |
| 227 | buffers. */ |
| 228 | for (tmp = first; total_lines - tmp->nlines > n_lines; tmp = tmp->next) |
| 229 | total_lines -= tmp->nlines; |
Erik Andersen | 3fe39dc | 2000-01-25 18:13:53 +0000 | [diff] [blame] | 230 | |
Erik Andersen | e49d5ec | 2000-02-08 19:58:47 +0000 | [diff] [blame] | 231 | /* Find the correct beginning, then print the rest of the file. */ |
| 232 | if (total_lines > n_lines) { |
| 233 | char *cp; |
Erik Andersen | 3fe39dc | 2000-01-25 18:13:53 +0000 | [diff] [blame] | 234 | |
Erik Andersen | e49d5ec | 2000-02-08 19:58:47 +0000 | [diff] [blame] | 235 | /* Skip `total_lines' - `n_lines' newlines. We made sure that |
| 236 | `total_lines' - `n_lines' <= `tmp->nlines'. */ |
| 237 | cp = tmp->buffer; |
| 238 | for (i = total_lines - n_lines; i; --i) |
| 239 | while (*cp++ != '\n') |
| 240 | /* Do nothing. */ ; |
| 241 | i = cp - tmp->buffer; |
| 242 | } else |
| 243 | i = 0; |
| 244 | XWRITE(STDOUT_FILENO, &tmp->buffer[i], tmp->nbytes - i); |
Erik Andersen | 3fe39dc | 2000-01-25 18:13:53 +0000 | [diff] [blame] | 245 | |
Erik Andersen | e49d5ec | 2000-02-08 19:58:47 +0000 | [diff] [blame] | 246 | for (tmp = tmp->next; tmp; tmp = tmp->next) |
| 247 | XWRITE(STDOUT_FILENO, tmp->buffer, tmp->nbytes); |
Erik Andersen | 3fe39dc | 2000-01-25 18:13:53 +0000 | [diff] [blame] | 248 | |
| 249 | free_lbuffers: |
Erik Andersen | e49d5ec | 2000-02-08 19:58:47 +0000 | [diff] [blame] | 250 | while (first) { |
| 251 | tmp = first->next; |
| 252 | free((char *) first); |
| 253 | first = tmp; |
| 254 | } |
| 255 | return errors; |
Erik Andersen | 3fe39dc | 2000-01-25 18:13:53 +0000 | [diff] [blame] | 256 | } |
| 257 | |
| 258 | /* Display file FILENAME from the current position in FD to the end. |
| 259 | If `forever' is nonzero, keep reading from the end of the file |
| 260 | until killed. Return the number of bytes read from the file. */ |
| 261 | |
| 262 | static long dump_remainder(const char *filename, int fd) |
| 263 | { |
Erik Andersen | e49d5ec | 2000-02-08 19:58:47 +0000 | [diff] [blame] | 264 | char buffer[BUFSIZ]; |
| 265 | int bytes_read; |
| 266 | long total; |
Erik Andersen | 3fe39dc | 2000-01-25 18:13:53 +0000 | [diff] [blame] | 267 | |
Erik Andersen | e49d5ec | 2000-02-08 19:58:47 +0000 | [diff] [blame] | 268 | total = 0; |
Erik Andersen | 3fe39dc | 2000-01-25 18:13:53 +0000 | [diff] [blame] | 269 | output: |
Erik Andersen | e49d5ec | 2000-02-08 19:58:47 +0000 | [diff] [blame] | 270 | while ((bytes_read = fullRead(fd, buffer, BUFSIZ)) > 0) { |
| 271 | XWRITE(STDOUT_FILENO, buffer, bytes_read); |
| 272 | total += bytes_read; |
| 273 | } |
| 274 | if (bytes_read == -1) |
| 275 | error("read error"); |
| 276 | if (forever) { |
| 277 | fflush(stdout); |
| 278 | sleep(1); |
| 279 | goto output; |
| 280 | } |
Erik Andersen | 3fe39dc | 2000-01-25 18:13:53 +0000 | [diff] [blame] | 281 | |
Erik Andersen | e49d5ec | 2000-02-08 19:58:47 +0000 | [diff] [blame] | 282 | return total; |
Erik Andersen | 3fe39dc | 2000-01-25 18:13:53 +0000 | [diff] [blame] | 283 | } |
| 284 | |
| 285 | /* Output the last N_LINES lines of file FILENAME open for reading in FD. |
| 286 | Return 0 if successful, 1 if an error occurred. */ |
| 287 | |
| 288 | static int tail_lines(const char *filename, int fd, long int n_lines) |
| 289 | { |
Erik Andersen | e49d5ec | 2000-02-08 19:58:47 +0000 | [diff] [blame] | 290 | struct stat stats; |
| 291 | off_t length; |
Erik Andersen | 3fe39dc | 2000-01-25 18:13:53 +0000 | [diff] [blame] | 292 | |
Erik Andersen | e49d5ec | 2000-02-08 19:58:47 +0000 | [diff] [blame] | 293 | if (print_headers) |
| 294 | write_header(filename); |
Erik Andersen | 3fe39dc | 2000-01-25 18:13:53 +0000 | [diff] [blame] | 295 | |
Erik Andersen | e49d5ec | 2000-02-08 19:58:47 +0000 | [diff] [blame] | 296 | if (fstat(fd, &stats)) |
| 297 | error("fstat error"); |
Erik Andersen | 3fe39dc | 2000-01-25 18:13:53 +0000 | [diff] [blame] | 298 | |
Erik Andersen | e49d5ec | 2000-02-08 19:58:47 +0000 | [diff] [blame] | 299 | /* Use file_lines only if FD refers to a regular file with |
| 300 | its file pointer positioned at beginning of file. */ |
| 301 | /* FIXME: adding the lseek conjunct is a kludge. |
| 302 | Once there's a reasonable test suite, fix the true culprit: |
| 303 | file_lines. file_lines shouldn't presume that the input |
| 304 | file pointer is initially positioned to beginning of file. */ |
| 305 | if (S_ISREG(stats.st_mode) |
| 306 | && lseek(fd, (off_t) 0, SEEK_CUR) == (off_t) 0) { |
| 307 | length = lseek(fd, (off_t) 0, SEEK_END); |
| 308 | if (length != 0 && file_lines(filename, fd, n_lines, length)) |
| 309 | return 1; |
| 310 | dump_remainder(filename, fd); |
| 311 | } else |
| 312 | return pipe_lines(filename, fd, n_lines); |
Erik Andersen | 3fe39dc | 2000-01-25 18:13:53 +0000 | [diff] [blame] | 313 | |
Erik Andersen | e49d5ec | 2000-02-08 19:58:47 +0000 | [diff] [blame] | 314 | return 0; |
Erik Andersen | 3fe39dc | 2000-01-25 18:13:53 +0000 | [diff] [blame] | 315 | } |
| 316 | |
| 317 | /* Display the last N_UNITS lines of file FILENAME. |
| 318 | "-" for FILENAME means the standard input. |
| 319 | Return 0 if successful, 1 if an error occurred. */ |
| 320 | |
| 321 | static int tail_file(const char *filename, off_t n_units) |
| 322 | { |
Erik Andersen | e49d5ec | 2000-02-08 19:58:47 +0000 | [diff] [blame] | 323 | int fd, errors; |
Erik Andersen | 3fe39dc | 2000-01-25 18:13:53 +0000 | [diff] [blame] | 324 | |
Erik Andersen | e49d5ec | 2000-02-08 19:58:47 +0000 | [diff] [blame] | 325 | if (!strcmp(filename, "-")) { |
| 326 | filename = "standard input"; |
| 327 | errors = tail_lines(filename, 0, (long) n_units); |
| 328 | } else { |
| 329 | /* Not standard input. */ |
| 330 | fd = open(filename, O_RDONLY); |
| 331 | if (fd == -1) |
| 332 | error("open error"); |
Erik Andersen | 3fe39dc | 2000-01-25 18:13:53 +0000 | [diff] [blame] | 333 | |
Erik Andersen | e49d5ec | 2000-02-08 19:58:47 +0000 | [diff] [blame] | 334 | errors = tail_lines(filename, fd, (long) n_units); |
| 335 | close(fd); |
| 336 | } |
Erik Andersen | 3fe39dc | 2000-01-25 18:13:53 +0000 | [diff] [blame] | 337 | |
Erik Andersen | e49d5ec | 2000-02-08 19:58:47 +0000 | [diff] [blame] | 338 | return errors; |
Erik Andersen | 3fe39dc | 2000-01-25 18:13:53 +0000 | [diff] [blame] | 339 | } |
| 340 | |
| 341 | extern int tail_main(int argc, char **argv) |
| 342 | { |
Erik Andersen | e49d5ec | 2000-02-08 19:58:47 +0000 | [diff] [blame] | 343 | int exit_status = 0; |
| 344 | int n_units = DEFAULT_N_LINES; |
| 345 | int n_tmp, i; |
| 346 | char opt; |
Erik Andersen | 3fe39dc | 2000-01-25 18:13:53 +0000 | [diff] [blame] | 347 | |
Erik Andersen | e49d5ec | 2000-02-08 19:58:47 +0000 | [diff] [blame] | 348 | forever = print_headers = 0; |
Erik Andersen | 3fe39dc | 2000-01-25 18:13:53 +0000 | [diff] [blame] | 349 | |
Erik Andersen | e49d5ec | 2000-02-08 19:58:47 +0000 | [diff] [blame] | 350 | /* parse argv[] */ |
| 351 | for (i = 1; i < argc; i++) { |
| 352 | if (argv[i][0] == '-') { |
| 353 | opt = argv[i][1]; |
| 354 | switch (opt) { |
| 355 | case 'f': |
| 356 | forever = 1; |
| 357 | break; |
| 358 | case 'n': |
| 359 | n_tmp = 0; |
| 360 | if (++i < argc) |
| 361 | n_tmp = atoi(argv[i]); |
| 362 | if (n_tmp < 1) |
| 363 | usage(tail_usage); |
| 364 | n_units = n_tmp; |
| 365 | break; |
| 366 | case '-': |
| 367 | case 'h': |
| 368 | usage(tail_usage); |
| 369 | default: |
| 370 | fprintf(stderr, "tail: invalid option -- %c\n", opt); |
| 371 | usage(tail_usage); |
| 372 | } |
| 373 | } else { |
| 374 | break; |
| 375 | } |
| 376 | } |
| 377 | |
| 378 | if (i + 1 < argc) { |
| 379 | if (forever) { |
| 380 | fprintf(stderr, |
| 381 | "tail: option -f is invalid with multiple files\n"); |
| 382 | usage(tail_usage); |
| 383 | } |
| 384 | print_headers = 1; |
| 385 | } |
| 386 | |
| 387 | if (i >= argc) { |
| 388 | exit_status |= tail_file("-", n_units); |
Erik Andersen | 3fe39dc | 2000-01-25 18:13:53 +0000 | [diff] [blame] | 389 | } else { |
Erik Andersen | e49d5ec | 2000-02-08 19:58:47 +0000 | [diff] [blame] | 390 | for (; i < argc; i++) |
| 391 | exit_status |= tail_file(argv[i], n_units); |
Erik Andersen | 3fe39dc | 2000-01-25 18:13:53 +0000 | [diff] [blame] | 392 | } |
Erik Andersen | 3fe39dc | 2000-01-25 18:13:53 +0000 | [diff] [blame] | 393 | |
Erik Andersen | e49d5ec | 2000-02-08 19:58:47 +0000 | [diff] [blame] | 394 | exit(exit_status == 0 ? EXIT_SUCCESS : EXIT_FAILURE); |
Erik Andersen | 3fe39dc | 2000-01-25 18:13:53 +0000 | [diff] [blame] | 395 | } |
| 396 | |
| 397 | |
| 398 | #else |
| 399 | // Here follows the code for the full featured tail code |
| 400 | |
| 401 | |
Eric Andersen | abc0f4f | 1999-12-08 23:19:36 +0000 | [diff] [blame] | 402 | /* tail -- output the last part of file(s) |
| 403 | Copyright (C) 89, 90, 91, 95, 1996 Free Software Foundation, Inc. |
| 404 | |
| 405 | This program is free software; you can redistribute it and/or modify |
| 406 | it under the terms of the GNU General Public License as published by |
| 407 | the Free Software Foundation; either version 2, or (at your option) |
| 408 | any later version. |
| 409 | |
| 410 | This program is distributed in the hope that it will be useful, |
| 411 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 412 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 413 | GNU General Public License for more details. |
| 414 | |
| 415 | You should have received a copy of the GNU General Public License |
| 416 | along with this program; if not, write to the Free Software |
Eric Andersen | 1792f8c | 1999-12-09 06:11:36 +0000 | [diff] [blame] | 417 | Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. |
Eric Andersen | abc0f4f | 1999-12-08 23:19:36 +0000 | [diff] [blame] | 418 | |
| 419 | Original version by Paul Rubin <phr@ocf.berkeley.edu>. |
| 420 | Extensions by David MacKenzie <djm@gnu.ai.mit.edu>. |
Eric Andersen | 1792f8c | 1999-12-09 06:11:36 +0000 | [diff] [blame] | 421 | tail -f for multiple files by Ian Lance Taylor <ian@airs.com>. |
| 422 | |
| 423 | Rewrote the option parser, removed locales support, |
| 424 | and generally busyboxed, Erik Andersen <andersen@lineo.com> |
| 425 | |
| 426 | */ |
Eric Andersen | abc0f4f | 1999-12-08 23:19:36 +0000 | [diff] [blame] | 427 | |
| 428 | #include "internal.h" |
| 429 | |
| 430 | #include <stdio.h> |
Erik Andersen | 4d1d011 | 1999-12-17 18:44:15 +0000 | [diff] [blame] | 431 | #include <stdarg.h> |
Eric Andersen | abc0f4f | 1999-12-08 23:19:36 +0000 | [diff] [blame] | 432 | #include <assert.h> |
| 433 | #include <errno.h> |
| 434 | #include <sys/types.h> |
Eric Andersen | 1792f8c | 1999-12-09 06:11:36 +0000 | [diff] [blame] | 435 | #include <sys/types.h> |
| 436 | #include <sys/stat.h> |
| 437 | #include <fcntl.h> |
| 438 | #include <ctype.h> |
| 439 | |
Eric Andersen | abc0f4f | 1999-12-08 23:19:36 +0000 | [diff] [blame] | 440 | |
| 441 | |
| 442 | /* Disable assertions. Some systems have broken assert macros. */ |
| 443 | #define NDEBUG 1 |
| 444 | |
| 445 | |
Erik Andersen | e49d5ec | 2000-02-08 19:58:47 +0000 | [diff] [blame] | 446 | static void detailed_error(int i, int errnum, char *fmt, ...) |
Eric Andersen | abc0f4f | 1999-12-08 23:19:36 +0000 | [diff] [blame] | 447 | { |
Erik Andersen | e49d5ec | 2000-02-08 19:58:47 +0000 | [diff] [blame] | 448 | va_list arguments; |
Eric Andersen | 1792f8c | 1999-12-09 06:11:36 +0000 | [diff] [blame] | 449 | |
Erik Andersen | e49d5ec | 2000-02-08 19:58:47 +0000 | [diff] [blame] | 450 | va_start(arguments, fmt); |
| 451 | vfprintf(stderr, fmt, arguments); |
| 452 | fprintf(stderr, "\n%s\n", strerror(errnum)); |
| 453 | va_end(arguments); |
| 454 | exit(i); |
Eric Andersen | abc0f4f | 1999-12-08 23:19:36 +0000 | [diff] [blame] | 455 | } |
| 456 | |
| 457 | |
| 458 | #define XWRITE(fd, buffer, n_bytes) \ |
| 459 | do \ |
| 460 | { \ |
| 461 | assert ((fd) == 1); \ |
| 462 | assert ((n_bytes) >= 0); \ |
| 463 | if (n_bytes > 0 && fwrite ((buffer), 1, (n_bytes), stdout) == 0) \ |
Erik Andersen | 3fe39dc | 2000-01-25 18:13:53 +0000 | [diff] [blame] | 464 | detailed_error (EXIT_FAILURE, errno, "write error"); \ |
Eric Andersen | abc0f4f | 1999-12-08 23:19:36 +0000 | [diff] [blame] | 465 | } \ |
| 466 | while (0) |
| 467 | |
| 468 | /* Number of items to tail. */ |
| 469 | #define DEFAULT_N_LINES 10 |
| 470 | |
| 471 | /* Size of atomic reads. */ |
| 472 | #ifndef BUFSIZ |
| 473 | #define BUFSIZ (512 * 8) |
| 474 | #endif |
| 475 | |
| 476 | /* If nonzero, interpret the numeric argument as the number of lines. |
| 477 | Otherwise, interpret it as the number of bytes. */ |
| 478 | static int count_lines; |
| 479 | |
| 480 | /* If nonzero, read from the end of one file until killed. */ |
| 481 | static int forever; |
| 482 | |
| 483 | /* If nonzero, read from the end of multiple files until killed. */ |
| 484 | static int forever_multiple; |
| 485 | |
| 486 | /* Array of file descriptors if forever_multiple is 1. */ |
| 487 | static int *file_descs; |
| 488 | |
| 489 | /* Array of file sizes if forever_multiple is 1. */ |
| 490 | static off_t *file_sizes; |
| 491 | |
| 492 | /* If nonzero, count from start of file instead of end. */ |
| 493 | static int from_start; |
| 494 | |
| 495 | /* If nonzero, print filename headers. */ |
| 496 | static int print_headers; |
| 497 | |
| 498 | /* When to print the filename banners. */ |
Erik Andersen | e49d5ec | 2000-02-08 19:58:47 +0000 | [diff] [blame] | 499 | enum header_mode { |
| 500 | multiple_files, always, never |
Eric Andersen | abc0f4f | 1999-12-08 23:19:36 +0000 | [diff] [blame] | 501 | }; |
| 502 | |
Eric Andersen | abc0f4f | 1999-12-08 23:19:36 +0000 | [diff] [blame] | 503 | /* The name this program was run with. */ |
| 504 | char *program_name; |
| 505 | |
| 506 | /* Nonzero if we have ever read standard input. */ |
| 507 | static int have_read_stdin; |
| 508 | |
Eric Andersen | abc0f4f | 1999-12-08 23:19:36 +0000 | [diff] [blame] | 509 | |
Erik Andersen | e49d5ec | 2000-02-08 19:58:47 +0000 | [diff] [blame] | 510 | static const char tail_usage[] = "tail [OPTION]... [FILE]...\n\ |
Eric Andersen | 1792f8c | 1999-12-09 06:11:36 +0000 | [diff] [blame] | 511 | \n\ |
Eric Andersen | abc0f4f | 1999-12-08 23:19:36 +0000 | [diff] [blame] | 512 | Print last 10 lines of each FILE to standard output.\n\ |
| 513 | With more than one FILE, precede each with a header giving the file name.\n\ |
| 514 | With no FILE, or when FILE is -, read standard input.\n\ |
| 515 | \n\ |
Eric Andersen | 1792f8c | 1999-12-09 06:11:36 +0000 | [diff] [blame] | 516 | -c=N[kbm] output the last N bytes\n\ |
| 517 | -f output appended data as the file grows\n\ |
| 518 | -n=N output the last N lines, instead of last 10\n\ |
| 519 | -q never output headers giving file names\n\ |
| 520 | -v always output headers giving file names\n\ |
| 521 | --help display this help and exit\n\ |
Eric Andersen | abc0f4f | 1999-12-08 23:19:36 +0000 | [diff] [blame] | 522 | \n\ |
Eric Andersen | 1792f8c | 1999-12-09 06:11:36 +0000 | [diff] [blame] | 523 | If the first character of N (bytes or lines) is a `+', output begins with \n\ |
| 524 | the Nth item from the start of each file, otherwise, print the last N items\n\ |
| 525 | in the file. N bytes may be suffixed by k (x1024), b (x512), or m (1024^2).\n\n"; |
Eric Andersen | abc0f4f | 1999-12-08 23:19:36 +0000 | [diff] [blame] | 526 | |
Erik Andersen | e49d5ec | 2000-02-08 19:58:47 +0000 | [diff] [blame] | 527 | static void write_header(const char *filename, const char *comment) |
Eric Andersen | abc0f4f | 1999-12-08 23:19:36 +0000 | [diff] [blame] | 528 | { |
Erik Andersen | e49d5ec | 2000-02-08 19:58:47 +0000 | [diff] [blame] | 529 | static int first_file = 1; |
Eric Andersen | abc0f4f | 1999-12-08 23:19:36 +0000 | [diff] [blame] | 530 | |
Erik Andersen | e49d5ec | 2000-02-08 19:58:47 +0000 | [diff] [blame] | 531 | printf("%s==> %s%s%s <==\n", (first_file ? "" : "\n"), filename, |
| 532 | (comment ? ": " : ""), (comment ? comment : "")); |
| 533 | first_file = 0; |
Eric Andersen | abc0f4f | 1999-12-08 23:19:36 +0000 | [diff] [blame] | 534 | } |
| 535 | |
| 536 | /* Print the last N_LINES lines from the end of file FD. |
| 537 | Go backward through the file, reading `BUFSIZ' bytes at a time (except |
| 538 | probably the first), until we hit the start of the file or have |
| 539 | read NUMBER newlines. |
| 540 | POS starts out as the length of the file (the offset of the last |
| 541 | byte of the file + 1). |
| 542 | Return 0 if successful, 1 if an error occurred. */ |
| 543 | |
| 544 | static int |
Erik Andersen | e49d5ec | 2000-02-08 19:58:47 +0000 | [diff] [blame] | 545 | file_lines(const char *filename, int fd, long int n_lines, off_t pos) |
Eric Andersen | abc0f4f | 1999-12-08 23:19:36 +0000 | [diff] [blame] | 546 | { |
Erik Andersen | e49d5ec | 2000-02-08 19:58:47 +0000 | [diff] [blame] | 547 | char buffer[BUFSIZ]; |
| 548 | int bytes_read; |
| 549 | int i; /* Index into `buffer' for scanning. */ |
Eric Andersen | abc0f4f | 1999-12-08 23:19:36 +0000 | [diff] [blame] | 550 | |
Erik Andersen | e49d5ec | 2000-02-08 19:58:47 +0000 | [diff] [blame] | 551 | if (n_lines == 0) |
| 552 | return 0; |
Eric Andersen | abc0f4f | 1999-12-08 23:19:36 +0000 | [diff] [blame] | 553 | |
Erik Andersen | e49d5ec | 2000-02-08 19:58:47 +0000 | [diff] [blame] | 554 | /* Set `bytes_read' to the size of the last, probably partial, buffer; |
| 555 | 0 < `bytes_read' <= `BUFSIZ'. */ |
| 556 | bytes_read = pos % BUFSIZ; |
| 557 | if (bytes_read == 0) |
| 558 | bytes_read = BUFSIZ; |
| 559 | /* Make `pos' a multiple of `BUFSIZ' (0 if the file is short), so that all |
| 560 | reads will be on block boundaries, which might increase efficiency. */ |
| 561 | pos -= bytes_read; |
| 562 | lseek(fd, pos, SEEK_SET); |
| 563 | bytes_read = fullRead(fd, buffer, bytes_read); |
| 564 | if (bytes_read == -1) { |
| 565 | detailed_error(0, errno, "%s", filename); |
| 566 | return 1; |
Eric Andersen | abc0f4f | 1999-12-08 23:19:36 +0000 | [diff] [blame] | 567 | } |
Erik Andersen | e49d5ec | 2000-02-08 19:58:47 +0000 | [diff] [blame] | 568 | |
| 569 | /* Count the incomplete line on files that don't end with a newline. */ |
| 570 | if (bytes_read && buffer[bytes_read - 1] != '\n') |
| 571 | --n_lines; |
| 572 | |
| 573 | do { |
| 574 | /* Scan backward, counting the newlines in this bufferfull. */ |
| 575 | for (i = bytes_read - 1; i >= 0; i--) { |
| 576 | /* Have we counted the requested number of newlines yet? */ |
| 577 | if (buffer[i] == '\n' && n_lines-- == 0) { |
| 578 | /* If this newline wasn't the last character in the buffer, |
| 579 | print the text after it. */ |
| 580 | if (i != bytes_read - 1) |
| 581 | XWRITE(STDOUT_FILENO, &buffer[i + 1], |
| 582 | bytes_read - (i + 1)); |
| 583 | return 0; |
| 584 | } |
| 585 | } |
| 586 | /* Not enough newlines in that bufferfull. */ |
| 587 | if (pos == 0) { |
| 588 | /* Not enough lines in the file; print the entire file. */ |
| 589 | lseek(fd, (off_t) 0, SEEK_SET); |
| 590 | return 0; |
| 591 | } |
| 592 | pos -= BUFSIZ; |
| 593 | lseek(fd, pos, SEEK_SET); |
Eric Andersen | abc0f4f | 1999-12-08 23:19:36 +0000 | [diff] [blame] | 594 | } |
Erik Andersen | e49d5ec | 2000-02-08 19:58:47 +0000 | [diff] [blame] | 595 | while ((bytes_read = fullRead(fd, buffer, BUFSIZ)) > 0); |
| 596 | if (bytes_read == -1) { |
| 597 | detailed_error(0, errno, "%s", filename); |
| 598 | return 1; |
| 599 | } |
| 600 | return 0; |
Eric Andersen | abc0f4f | 1999-12-08 23:19:36 +0000 | [diff] [blame] | 601 | } |
| 602 | |
| 603 | /* Print the last N_LINES lines from the end of the standard input, |
| 604 | open for reading as pipe FD. |
| 605 | Buffer the text as a linked list of LBUFFERs, adding them as needed. |
| 606 | Return 0 if successful, 1 if an error occured. */ |
| 607 | |
Erik Andersen | e49d5ec | 2000-02-08 19:58:47 +0000 | [diff] [blame] | 608 | static int pipe_lines(const char *filename, int fd, long int n_lines) |
Eric Andersen | abc0f4f | 1999-12-08 23:19:36 +0000 | [diff] [blame] | 609 | { |
Erik Andersen | e49d5ec | 2000-02-08 19:58:47 +0000 | [diff] [blame] | 610 | struct linebuffer { |
| 611 | int nbytes, nlines; |
| 612 | char buffer[BUFSIZ]; |
| 613 | struct linebuffer *next; |
| 614 | }; |
| 615 | typedef struct linebuffer LBUFFER; |
| 616 | LBUFFER *first, *last, *tmp; |
| 617 | int i; /* Index into buffers. */ |
| 618 | int total_lines = 0; /* Total number of newlines in all buffers. */ |
| 619 | int errors = 0; |
Eric Andersen | abc0f4f | 1999-12-08 23:19:36 +0000 | [diff] [blame] | 620 | |
Erik Andersen | e49d5ec | 2000-02-08 19:58:47 +0000 | [diff] [blame] | 621 | first = last = (LBUFFER *) xmalloc(sizeof(LBUFFER)); |
| 622 | first->nbytes = first->nlines = 0; |
| 623 | first->next = NULL; |
| 624 | tmp = (LBUFFER *) xmalloc(sizeof(LBUFFER)); |
Eric Andersen | abc0f4f | 1999-12-08 23:19:36 +0000 | [diff] [blame] | 625 | |
Erik Andersen | e49d5ec | 2000-02-08 19:58:47 +0000 | [diff] [blame] | 626 | /* Input is always read into a fresh buffer. */ |
| 627 | while ((tmp->nbytes = fullRead(fd, tmp->buffer, BUFSIZ)) > 0) { |
| 628 | tmp->nlines = 0; |
| 629 | tmp->next = NULL; |
Eric Andersen | abc0f4f | 1999-12-08 23:19:36 +0000 | [diff] [blame] | 630 | |
Erik Andersen | e49d5ec | 2000-02-08 19:58:47 +0000 | [diff] [blame] | 631 | /* Count the number of newlines just read. */ |
| 632 | for (i = 0; i < tmp->nbytes; i++) |
| 633 | if (tmp->buffer[i] == '\n') |
| 634 | ++tmp->nlines; |
| 635 | total_lines += tmp->nlines; |
Eric Andersen | abc0f4f | 1999-12-08 23:19:36 +0000 | [diff] [blame] | 636 | |
Erik Andersen | e49d5ec | 2000-02-08 19:58:47 +0000 | [diff] [blame] | 637 | /* If there is enough room in the last buffer read, just append the new |
| 638 | one to it. This is because when reading from a pipe, `nbytes' can |
| 639 | often be very small. */ |
| 640 | if (tmp->nbytes + last->nbytes < BUFSIZ) { |
| 641 | memcpy(&last->buffer[last->nbytes], tmp->buffer, tmp->nbytes); |
| 642 | last->nbytes += tmp->nbytes; |
| 643 | last->nlines += tmp->nlines; |
| 644 | } else { |
| 645 | /* If there's not enough room, link the new buffer onto the end of |
| 646 | the list, then either free up the oldest buffer for the next |
| 647 | read if that would leave enough lines, or else malloc a new one. |
| 648 | Some compaction mechanism is possible but probably not |
| 649 | worthwhile. */ |
| 650 | last = last->next = tmp; |
| 651 | if (total_lines - first->nlines > n_lines) { |
| 652 | tmp = first; |
| 653 | total_lines -= first->nlines; |
| 654 | first = first->next; |
| 655 | } else |
| 656 | tmp = (LBUFFER *) xmalloc(sizeof(LBUFFER)); |
| 657 | } |
Eric Andersen | abc0f4f | 1999-12-08 23:19:36 +0000 | [diff] [blame] | 658 | } |
Erik Andersen | e49d5ec | 2000-02-08 19:58:47 +0000 | [diff] [blame] | 659 | if (tmp->nbytes == -1) { |
| 660 | detailed_error(0, errno, "%s", filename); |
| 661 | errors = 1; |
| 662 | free((char *) tmp); |
| 663 | goto free_lbuffers; |
Eric Andersen | abc0f4f | 1999-12-08 23:19:36 +0000 | [diff] [blame] | 664 | } |
Eric Andersen | abc0f4f | 1999-12-08 23:19:36 +0000 | [diff] [blame] | 665 | |
Erik Andersen | e49d5ec | 2000-02-08 19:58:47 +0000 | [diff] [blame] | 666 | free((char *) tmp); |
Eric Andersen | abc0f4f | 1999-12-08 23:19:36 +0000 | [diff] [blame] | 667 | |
Erik Andersen | e49d5ec | 2000-02-08 19:58:47 +0000 | [diff] [blame] | 668 | /* This prevents a core dump when the pipe contains no newlines. */ |
| 669 | if (n_lines == 0) |
| 670 | goto free_lbuffers; |
Eric Andersen | abc0f4f | 1999-12-08 23:19:36 +0000 | [diff] [blame] | 671 | |
Erik Andersen | e49d5ec | 2000-02-08 19:58:47 +0000 | [diff] [blame] | 672 | /* Count the incomplete line on files that don't end with a newline. */ |
| 673 | if (last->buffer[last->nbytes - 1] != '\n') { |
| 674 | ++last->nlines; |
| 675 | ++total_lines; |
| 676 | } |
Eric Andersen | abc0f4f | 1999-12-08 23:19:36 +0000 | [diff] [blame] | 677 | |
Erik Andersen | e49d5ec | 2000-02-08 19:58:47 +0000 | [diff] [blame] | 678 | /* Run through the list, printing lines. First, skip over unneeded |
| 679 | buffers. */ |
| 680 | for (tmp = first; total_lines - tmp->nlines > n_lines; tmp = tmp->next) |
| 681 | total_lines -= tmp->nlines; |
Eric Andersen | abc0f4f | 1999-12-08 23:19:36 +0000 | [diff] [blame] | 682 | |
Erik Andersen | e49d5ec | 2000-02-08 19:58:47 +0000 | [diff] [blame] | 683 | /* Find the correct beginning, then print the rest of the file. */ |
| 684 | if (total_lines > n_lines) { |
| 685 | char *cp; |
Eric Andersen | abc0f4f | 1999-12-08 23:19:36 +0000 | [diff] [blame] | 686 | |
Erik Andersen | e49d5ec | 2000-02-08 19:58:47 +0000 | [diff] [blame] | 687 | /* Skip `total_lines' - `n_lines' newlines. We made sure that |
| 688 | `total_lines' - `n_lines' <= `tmp->nlines'. */ |
| 689 | cp = tmp->buffer; |
| 690 | for (i = total_lines - n_lines; i; --i) |
| 691 | while (*cp++ != '\n') |
| 692 | /* Do nothing. */ ; |
| 693 | i = cp - tmp->buffer; |
| 694 | } else |
| 695 | i = 0; |
| 696 | XWRITE(STDOUT_FILENO, &tmp->buffer[i], tmp->nbytes - i); |
Eric Andersen | abc0f4f | 1999-12-08 23:19:36 +0000 | [diff] [blame] | 697 | |
Erik Andersen | e49d5ec | 2000-02-08 19:58:47 +0000 | [diff] [blame] | 698 | for (tmp = tmp->next; tmp; tmp = tmp->next) |
| 699 | XWRITE(STDOUT_FILENO, tmp->buffer, tmp->nbytes); |
Eric Andersen | abc0f4f | 1999-12-08 23:19:36 +0000 | [diff] [blame] | 700 | |
Erik Andersen | e49d5ec | 2000-02-08 19:58:47 +0000 | [diff] [blame] | 701 | free_lbuffers: |
| 702 | while (first) { |
| 703 | tmp = first->next; |
| 704 | free((char *) first); |
| 705 | first = tmp; |
| 706 | } |
| 707 | return errors; |
Eric Andersen | abc0f4f | 1999-12-08 23:19:36 +0000 | [diff] [blame] | 708 | } |
| 709 | |
| 710 | /* Print the last N_BYTES characters from the end of pipe FD. |
| 711 | This is a stripped down version of pipe_lines. |
| 712 | Return 0 if successful, 1 if an error occurred. */ |
| 713 | |
Erik Andersen | e49d5ec | 2000-02-08 19:58:47 +0000 | [diff] [blame] | 714 | static int pipe_bytes(const char *filename, int fd, off_t n_bytes) |
Eric Andersen | abc0f4f | 1999-12-08 23:19:36 +0000 | [diff] [blame] | 715 | { |
Erik Andersen | e49d5ec | 2000-02-08 19:58:47 +0000 | [diff] [blame] | 716 | struct charbuffer { |
| 717 | int nbytes; |
| 718 | char buffer[BUFSIZ]; |
| 719 | struct charbuffer *next; |
| 720 | }; |
| 721 | typedef struct charbuffer CBUFFER; |
| 722 | CBUFFER *first, *last, *tmp; |
| 723 | int i; /* Index into buffers. */ |
| 724 | int total_bytes = 0; /* Total characters in all buffers. */ |
| 725 | int errors = 0; |
Eric Andersen | abc0f4f | 1999-12-08 23:19:36 +0000 | [diff] [blame] | 726 | |
Erik Andersen | e49d5ec | 2000-02-08 19:58:47 +0000 | [diff] [blame] | 727 | first = last = (CBUFFER *) xmalloc(sizeof(CBUFFER)); |
| 728 | first->nbytes = 0; |
| 729 | first->next = NULL; |
| 730 | tmp = (CBUFFER *) xmalloc(sizeof(CBUFFER)); |
Eric Andersen | abc0f4f | 1999-12-08 23:19:36 +0000 | [diff] [blame] | 731 | |
Erik Andersen | e49d5ec | 2000-02-08 19:58:47 +0000 | [diff] [blame] | 732 | /* Input is always read into a fresh buffer. */ |
| 733 | while ((tmp->nbytes = fullRead(fd, tmp->buffer, BUFSIZ)) > 0) { |
| 734 | tmp->next = NULL; |
Eric Andersen | abc0f4f | 1999-12-08 23:19:36 +0000 | [diff] [blame] | 735 | |
Erik Andersen | e49d5ec | 2000-02-08 19:58:47 +0000 | [diff] [blame] | 736 | total_bytes += tmp->nbytes; |
| 737 | /* If there is enough room in the last buffer read, just append the new |
| 738 | one to it. This is because when reading from a pipe, `nbytes' can |
| 739 | often be very small. */ |
| 740 | if (tmp->nbytes + last->nbytes < BUFSIZ) { |
| 741 | memcpy(&last->buffer[last->nbytes], tmp->buffer, tmp->nbytes); |
| 742 | last->nbytes += tmp->nbytes; |
| 743 | } else { |
| 744 | /* If there's not enough room, link the new buffer onto the end of |
| 745 | the list, then either free up the oldest buffer for the next |
| 746 | read if that would leave enough characters, or else malloc a new |
| 747 | one. Some compaction mechanism is possible but probably not |
| 748 | worthwhile. */ |
| 749 | last = last->next = tmp; |
| 750 | if (total_bytes - first->nbytes > n_bytes) { |
| 751 | tmp = first; |
| 752 | total_bytes -= first->nbytes; |
| 753 | first = first->next; |
| 754 | } else { |
| 755 | tmp = (CBUFFER *) xmalloc(sizeof(CBUFFER)); |
| 756 | } |
| 757 | } |
Eric Andersen | abc0f4f | 1999-12-08 23:19:36 +0000 | [diff] [blame] | 758 | } |
Erik Andersen | e49d5ec | 2000-02-08 19:58:47 +0000 | [diff] [blame] | 759 | if (tmp->nbytes == -1) { |
| 760 | detailed_error(0, errno, "%s", filename); |
| 761 | errors = 1; |
| 762 | free((char *) tmp); |
| 763 | goto free_cbuffers; |
Eric Andersen | abc0f4f | 1999-12-08 23:19:36 +0000 | [diff] [blame] | 764 | } |
Eric Andersen | abc0f4f | 1999-12-08 23:19:36 +0000 | [diff] [blame] | 765 | |
Erik Andersen | e49d5ec | 2000-02-08 19:58:47 +0000 | [diff] [blame] | 766 | free((char *) tmp); |
Eric Andersen | abc0f4f | 1999-12-08 23:19:36 +0000 | [diff] [blame] | 767 | |
Erik Andersen | e49d5ec | 2000-02-08 19:58:47 +0000 | [diff] [blame] | 768 | /* Run through the list, printing characters. First, skip over unneeded |
| 769 | buffers. */ |
| 770 | for (tmp = first; total_bytes - tmp->nbytes > n_bytes; tmp = tmp->next) |
| 771 | total_bytes -= tmp->nbytes; |
Eric Andersen | abc0f4f | 1999-12-08 23:19:36 +0000 | [diff] [blame] | 772 | |
Erik Andersen | e49d5ec | 2000-02-08 19:58:47 +0000 | [diff] [blame] | 773 | /* Find the correct beginning, then print the rest of the file. |
| 774 | We made sure that `total_bytes' - `n_bytes' <= `tmp->nbytes'. */ |
| 775 | if (total_bytes > n_bytes) |
| 776 | i = total_bytes - n_bytes; |
| 777 | else |
| 778 | i = 0; |
| 779 | XWRITE(STDOUT_FILENO, &tmp->buffer[i], tmp->nbytes - i); |
Eric Andersen | abc0f4f | 1999-12-08 23:19:36 +0000 | [diff] [blame] | 780 | |
Erik Andersen | e49d5ec | 2000-02-08 19:58:47 +0000 | [diff] [blame] | 781 | for (tmp = tmp->next; tmp; tmp = tmp->next) |
| 782 | XWRITE(STDOUT_FILENO, tmp->buffer, tmp->nbytes); |
Eric Andersen | abc0f4f | 1999-12-08 23:19:36 +0000 | [diff] [blame] | 783 | |
Erik Andersen | e49d5ec | 2000-02-08 19:58:47 +0000 | [diff] [blame] | 784 | free_cbuffers: |
| 785 | while (first) { |
| 786 | tmp = first->next; |
| 787 | free((char *) first); |
| 788 | first = tmp; |
| 789 | } |
| 790 | return errors; |
Eric Andersen | abc0f4f | 1999-12-08 23:19:36 +0000 | [diff] [blame] | 791 | } |
| 792 | |
| 793 | /* Skip N_BYTES characters from the start of pipe FD, and print |
| 794 | any extra characters that were read beyond that. |
| 795 | Return 1 on error, 0 if ok. */ |
| 796 | |
Erik Andersen | e49d5ec | 2000-02-08 19:58:47 +0000 | [diff] [blame] | 797 | static int start_bytes(const char *filename, int fd, off_t n_bytes) |
Eric Andersen | abc0f4f | 1999-12-08 23:19:36 +0000 | [diff] [blame] | 798 | { |
Erik Andersen | e49d5ec | 2000-02-08 19:58:47 +0000 | [diff] [blame] | 799 | char buffer[BUFSIZ]; |
| 800 | int bytes_read = 0; |
Eric Andersen | abc0f4f | 1999-12-08 23:19:36 +0000 | [diff] [blame] | 801 | |
Erik Andersen | e49d5ec | 2000-02-08 19:58:47 +0000 | [diff] [blame] | 802 | while (n_bytes > 0 && (bytes_read = fullRead(fd, buffer, BUFSIZ)) > 0) |
| 803 | n_bytes -= bytes_read; |
| 804 | if (bytes_read == -1) { |
| 805 | detailed_error(0, errno, "%s", filename); |
| 806 | return 1; |
| 807 | } else if (n_bytes < 0) |
| 808 | XWRITE(STDOUT_FILENO, &buffer[bytes_read + n_bytes], -n_bytes); |
| 809 | return 0; |
Eric Andersen | abc0f4f | 1999-12-08 23:19:36 +0000 | [diff] [blame] | 810 | } |
| 811 | |
| 812 | /* Skip N_LINES lines at the start of file or pipe FD, and print |
| 813 | any extra characters that were read beyond that. |
| 814 | Return 1 on error, 0 if ok. */ |
| 815 | |
Erik Andersen | e49d5ec | 2000-02-08 19:58:47 +0000 | [diff] [blame] | 816 | static int start_lines(const char *filename, int fd, long int n_lines) |
Eric Andersen | abc0f4f | 1999-12-08 23:19:36 +0000 | [diff] [blame] | 817 | { |
Erik Andersen | e49d5ec | 2000-02-08 19:58:47 +0000 | [diff] [blame] | 818 | char buffer[BUFSIZ]; |
| 819 | int bytes_read = 0; |
| 820 | int bytes_to_skip = 0; |
Eric Andersen | abc0f4f | 1999-12-08 23:19:36 +0000 | [diff] [blame] | 821 | |
Erik Andersen | e49d5ec | 2000-02-08 19:58:47 +0000 | [diff] [blame] | 822 | while (n_lines && (bytes_read = fullRead(fd, buffer, BUFSIZ)) > 0) { |
| 823 | bytes_to_skip = 0; |
| 824 | while (bytes_to_skip < bytes_read) |
| 825 | if (buffer[bytes_to_skip++] == '\n' && --n_lines == 0) |
| 826 | break; |
| 827 | } |
| 828 | if (bytes_read == -1) { |
| 829 | detailed_error(0, errno, "%s", filename); |
| 830 | return 1; |
| 831 | } else if (bytes_to_skip < bytes_read) { |
| 832 | XWRITE(STDOUT_FILENO, &buffer[bytes_to_skip], |
| 833 | bytes_read - bytes_to_skip); |
| 834 | } |
| 835 | return 0; |
Eric Andersen | abc0f4f | 1999-12-08 23:19:36 +0000 | [diff] [blame] | 836 | } |
| 837 | |
| 838 | /* Display file FILENAME from the current position in FD to the end. |
| 839 | If `forever' is nonzero, keep reading from the end of the file |
| 840 | until killed. Return the number of bytes read from the file. */ |
| 841 | |
Erik Andersen | e49d5ec | 2000-02-08 19:58:47 +0000 | [diff] [blame] | 842 | static long dump_remainder(const char *filename, int fd) |
Eric Andersen | abc0f4f | 1999-12-08 23:19:36 +0000 | [diff] [blame] | 843 | { |
Erik Andersen | e49d5ec | 2000-02-08 19:58:47 +0000 | [diff] [blame] | 844 | char buffer[BUFSIZ]; |
| 845 | int bytes_read; |
| 846 | long total; |
Eric Andersen | abc0f4f | 1999-12-08 23:19:36 +0000 | [diff] [blame] | 847 | |
Erik Andersen | e49d5ec | 2000-02-08 19:58:47 +0000 | [diff] [blame] | 848 | total = 0; |
| 849 | output: |
| 850 | while ((bytes_read = fullRead(fd, buffer, BUFSIZ)) > 0) { |
| 851 | XWRITE(STDOUT_FILENO, buffer, bytes_read); |
| 852 | total += bytes_read; |
| 853 | } |
| 854 | if (bytes_read == -1) |
| 855 | detailed_error(EXIT_FAILURE, errno, "%s", filename); |
| 856 | if (forever) { |
| 857 | fflush(stdout); |
| 858 | sleep(1); |
| 859 | goto output; |
| 860 | } else { |
| 861 | if (forever_multiple) |
| 862 | fflush(stdout); |
| 863 | } |
Eric Andersen | abc0f4f | 1999-12-08 23:19:36 +0000 | [diff] [blame] | 864 | |
Erik Andersen | e49d5ec | 2000-02-08 19:58:47 +0000 | [diff] [blame] | 865 | return total; |
Eric Andersen | abc0f4f | 1999-12-08 23:19:36 +0000 | [diff] [blame] | 866 | } |
| 867 | |
| 868 | /* Tail NFILES (>1) files forever until killed. The file names are in |
| 869 | NAMES. The open file descriptors are in `file_descs', and the size |
| 870 | at which we stopped tailing them is in `file_sizes'. We loop over |
| 871 | each of them, doing an fstat to see if they have changed size. If |
| 872 | none of them have changed size in one iteration, we sleep for a |
| 873 | second and try again. We do this until the user interrupts us. */ |
| 874 | |
Erik Andersen | e49d5ec | 2000-02-08 19:58:47 +0000 | [diff] [blame] | 875 | static void tail_forever(char **names, int nfiles) |
Eric Andersen | abc0f4f | 1999-12-08 23:19:36 +0000 | [diff] [blame] | 876 | { |
Erik Andersen | e49d5ec | 2000-02-08 19:58:47 +0000 | [diff] [blame] | 877 | int last; |
Eric Andersen | abc0f4f | 1999-12-08 23:19:36 +0000 | [diff] [blame] | 878 | |
Erik Andersen | e49d5ec | 2000-02-08 19:58:47 +0000 | [diff] [blame] | 879 | last = -1; |
Eric Andersen | abc0f4f | 1999-12-08 23:19:36 +0000 | [diff] [blame] | 880 | |
Erik Andersen | e49d5ec | 2000-02-08 19:58:47 +0000 | [diff] [blame] | 881 | while (1) { |
| 882 | int i; |
| 883 | int changed; |
Eric Andersen | abc0f4f | 1999-12-08 23:19:36 +0000 | [diff] [blame] | 884 | |
Erik Andersen | e49d5ec | 2000-02-08 19:58:47 +0000 | [diff] [blame] | 885 | changed = 0; |
| 886 | for (i = 0; i < nfiles; i++) { |
| 887 | struct stat stats; |
Eric Andersen | abc0f4f | 1999-12-08 23:19:36 +0000 | [diff] [blame] | 888 | |
Erik Andersen | e49d5ec | 2000-02-08 19:58:47 +0000 | [diff] [blame] | 889 | if (file_descs[i] < 0) |
| 890 | continue; |
| 891 | if (fstat(file_descs[i], &stats) < 0) { |
| 892 | detailed_error(0, errno, "%s", names[i]); |
| 893 | file_descs[i] = -1; |
| 894 | continue; |
| 895 | } |
| 896 | if (stats.st_size == file_sizes[i]) |
| 897 | continue; |
Eric Andersen | abc0f4f | 1999-12-08 23:19:36 +0000 | [diff] [blame] | 898 | |
Erik Andersen | e49d5ec | 2000-02-08 19:58:47 +0000 | [diff] [blame] | 899 | /* This file has changed size. Print out what we can, and |
| 900 | then keep looping. */ |
Eric Andersen | abc0f4f | 1999-12-08 23:19:36 +0000 | [diff] [blame] | 901 | |
Erik Andersen | e49d5ec | 2000-02-08 19:58:47 +0000 | [diff] [blame] | 902 | changed = 1; |
Eric Andersen | abc0f4f | 1999-12-08 23:19:36 +0000 | [diff] [blame] | 903 | |
Erik Andersen | e49d5ec | 2000-02-08 19:58:47 +0000 | [diff] [blame] | 904 | if (stats.st_size < file_sizes[i]) { |
| 905 | write_header(names[i], "file truncated"); |
| 906 | last = i; |
| 907 | lseek(file_descs[i], stats.st_size, SEEK_SET); |
| 908 | file_sizes[i] = stats.st_size; |
| 909 | continue; |
| 910 | } |
Eric Andersen | abc0f4f | 1999-12-08 23:19:36 +0000 | [diff] [blame] | 911 | |
Erik Andersen | e49d5ec | 2000-02-08 19:58:47 +0000 | [diff] [blame] | 912 | if (i != last) { |
| 913 | if (print_headers) |
| 914 | write_header(names[i], NULL); |
| 915 | last = i; |
| 916 | } |
| 917 | file_sizes[i] += dump_remainder(names[i], file_descs[i]); |
| 918 | } |
| 919 | |
| 920 | /* If none of the files changed size, sleep. */ |
| 921 | if (!changed) |
| 922 | sleep(1); |
Eric Andersen | abc0f4f | 1999-12-08 23:19:36 +0000 | [diff] [blame] | 923 | } |
Eric Andersen | abc0f4f | 1999-12-08 23:19:36 +0000 | [diff] [blame] | 924 | } |
| 925 | |
| 926 | /* Output the last N_BYTES bytes of file FILENAME open for reading in FD. |
| 927 | Return 0 if successful, 1 if an error occurred. */ |
| 928 | |
Erik Andersen | e49d5ec | 2000-02-08 19:58:47 +0000 | [diff] [blame] | 929 | static int tail_bytes(const char *filename, int fd, off_t n_bytes) |
Eric Andersen | abc0f4f | 1999-12-08 23:19:36 +0000 | [diff] [blame] | 930 | { |
Erik Andersen | e49d5ec | 2000-02-08 19:58:47 +0000 | [diff] [blame] | 931 | struct stat stats; |
Eric Andersen | abc0f4f | 1999-12-08 23:19:36 +0000 | [diff] [blame] | 932 | |
Erik Andersen | e49d5ec | 2000-02-08 19:58:47 +0000 | [diff] [blame] | 933 | /* FIXME: resolve this like in dd.c. */ |
| 934 | /* Use fstat instead of checking for errno == ESPIPE because |
| 935 | lseek doesn't work on some special files but doesn't return an |
| 936 | error, either. */ |
| 937 | if (fstat(fd, &stats)) { |
| 938 | detailed_error(0, errno, "%s", filename); |
| 939 | return 1; |
Eric Andersen | abc0f4f | 1999-12-08 23:19:36 +0000 | [diff] [blame] | 940 | } |
Erik Andersen | e49d5ec | 2000-02-08 19:58:47 +0000 | [diff] [blame] | 941 | |
| 942 | if (from_start) { |
| 943 | if (S_ISREG(stats.st_mode)) |
| 944 | lseek(fd, n_bytes, SEEK_CUR); |
| 945 | else if (start_bytes(filename, fd, n_bytes)) |
| 946 | return 1; |
| 947 | dump_remainder(filename, fd); |
| 948 | } else { |
| 949 | if (S_ISREG(stats.st_mode)) { |
| 950 | off_t current_pos, end_pos; |
| 951 | size_t bytes_remaining; |
| 952 | |
| 953 | if ((current_pos = lseek(fd, (off_t) 0, SEEK_CUR)) != -1 |
| 954 | && (end_pos = lseek(fd, (off_t) 0, SEEK_END)) != -1) { |
| 955 | off_t diff; |
| 956 | |
| 957 | /* Be careful here. The current position may actually be |
| 958 | beyond the end of the file. */ |
| 959 | bytes_remaining = (diff = |
| 960 | end_pos - current_pos) < 0 ? 0 : diff; |
| 961 | } else { |
| 962 | detailed_error(0, errno, "%s", filename); |
| 963 | return 1; |
| 964 | } |
| 965 | |
| 966 | if (bytes_remaining <= n_bytes) { |
| 967 | /* From the current position to end of file, there are no |
| 968 | more bytes than have been requested. So reposition the |
| 969 | file pointer to the incoming current position and print |
| 970 | everything after that. */ |
| 971 | lseek(fd, current_pos, SEEK_SET); |
| 972 | } else { |
| 973 | /* There are more bytes remaining than were requested. |
| 974 | Back up. */ |
| 975 | lseek(fd, -n_bytes, SEEK_END); |
| 976 | } |
| 977 | dump_remainder(filename, fd); |
| 978 | } else |
| 979 | return pipe_bytes(filename, fd, n_bytes); |
| 980 | } |
| 981 | return 0; |
Eric Andersen | abc0f4f | 1999-12-08 23:19:36 +0000 | [diff] [blame] | 982 | } |
| 983 | |
| 984 | /* Output the last N_LINES lines of file FILENAME open for reading in FD. |
| 985 | Return 0 if successful, 1 if an error occurred. */ |
| 986 | |
Erik Andersen | e49d5ec | 2000-02-08 19:58:47 +0000 | [diff] [blame] | 987 | static int tail_lines(const char *filename, int fd, long int n_lines) |
Eric Andersen | abc0f4f | 1999-12-08 23:19:36 +0000 | [diff] [blame] | 988 | { |
Erik Andersen | e49d5ec | 2000-02-08 19:58:47 +0000 | [diff] [blame] | 989 | struct stat stats; |
| 990 | off_t length; |
Eric Andersen | abc0f4f | 1999-12-08 23:19:36 +0000 | [diff] [blame] | 991 | |
Erik Andersen | e49d5ec | 2000-02-08 19:58:47 +0000 | [diff] [blame] | 992 | if (fstat(fd, &stats)) { |
| 993 | detailed_error(0, errno, "%s", filename); |
| 994 | return 1; |
Eric Andersen | abc0f4f | 1999-12-08 23:19:36 +0000 | [diff] [blame] | 995 | } |
Erik Andersen | e49d5ec | 2000-02-08 19:58:47 +0000 | [diff] [blame] | 996 | |
| 997 | if (from_start) { |
| 998 | if (start_lines(filename, fd, n_lines)) |
| 999 | return 1; |
| 1000 | dump_remainder(filename, fd); |
| 1001 | } else { |
| 1002 | /* Use file_lines only if FD refers to a regular file with |
| 1003 | its file pointer positioned at beginning of file. */ |
| 1004 | /* FIXME: adding the lseek conjunct is a kludge. |
| 1005 | Once there's a reasonable test suite, fix the true culprit: |
| 1006 | file_lines. file_lines shouldn't presume that the input |
| 1007 | file pointer is initially positioned to beginning of file. */ |
| 1008 | if (S_ISREG(stats.st_mode) |
| 1009 | && lseek(fd, (off_t) 0, SEEK_CUR) == (off_t) 0) { |
| 1010 | length = lseek(fd, (off_t) 0, SEEK_END); |
| 1011 | if (length != 0 && file_lines(filename, fd, n_lines, length)) |
| 1012 | return 1; |
| 1013 | dump_remainder(filename, fd); |
| 1014 | } else |
| 1015 | return pipe_lines(filename, fd, n_lines); |
| 1016 | } |
| 1017 | return 0; |
Eric Andersen | abc0f4f | 1999-12-08 23:19:36 +0000 | [diff] [blame] | 1018 | } |
| 1019 | |
| 1020 | /* Display the last N_UNITS units of file FILENAME, open for reading |
| 1021 | in FD. |
| 1022 | Return 0 if successful, 1 if an error occurred. */ |
| 1023 | |
Erik Andersen | e49d5ec | 2000-02-08 19:58:47 +0000 | [diff] [blame] | 1024 | static int tail(const char *filename, int fd, off_t n_units) |
Eric Andersen | abc0f4f | 1999-12-08 23:19:36 +0000 | [diff] [blame] | 1025 | { |
Erik Andersen | e49d5ec | 2000-02-08 19:58:47 +0000 | [diff] [blame] | 1026 | if (count_lines) |
| 1027 | return tail_lines(filename, fd, (long) n_units); |
| 1028 | else |
| 1029 | return tail_bytes(filename, fd, n_units); |
Eric Andersen | abc0f4f | 1999-12-08 23:19:36 +0000 | [diff] [blame] | 1030 | } |
| 1031 | |
| 1032 | /* Display the last N_UNITS units of file FILENAME. |
| 1033 | "-" for FILENAME means the standard input. |
| 1034 | FILENUM is this file's index in the list of files the user gave. |
| 1035 | Return 0 if successful, 1 if an error occurred. */ |
| 1036 | |
Erik Andersen | e49d5ec | 2000-02-08 19:58:47 +0000 | [diff] [blame] | 1037 | static int tail_file(const char *filename, off_t n_units, int filenum) |
Eric Andersen | abc0f4f | 1999-12-08 23:19:36 +0000 | [diff] [blame] | 1038 | { |
Erik Andersen | e49d5ec | 2000-02-08 19:58:47 +0000 | [diff] [blame] | 1039 | int fd, errors; |
| 1040 | struct stat stats; |
Eric Andersen | abc0f4f | 1999-12-08 23:19:36 +0000 | [diff] [blame] | 1041 | |
Erik Andersen | e49d5ec | 2000-02-08 19:58:47 +0000 | [diff] [blame] | 1042 | if (!strcmp(filename, "-")) { |
| 1043 | have_read_stdin = 1; |
| 1044 | filename = "standard input"; |
| 1045 | if (print_headers) |
| 1046 | write_header(filename, NULL); |
| 1047 | errors = tail(filename, 0, n_units); |
| 1048 | if (forever_multiple) { |
| 1049 | if (fstat(0, &stats) < 0) { |
| 1050 | detailed_error(0, errno, "standard input"); |
| 1051 | errors = 1; |
| 1052 | } else if (!S_ISREG(stats.st_mode)) { |
| 1053 | detailed_error(0, 0, |
| 1054 | "standard input: cannot follow end of non-regular file"); |
| 1055 | errors = 1; |
| 1056 | } |
| 1057 | if (errors) |
| 1058 | file_descs[filenum] = -1; |
| 1059 | else { |
| 1060 | file_descs[filenum] = 0; |
| 1061 | file_sizes[filenum] = stats.st_size; |
| 1062 | } |
| 1063 | } |
| 1064 | } else { |
| 1065 | /* Not standard input. */ |
| 1066 | fd = open(filename, O_RDONLY); |
| 1067 | if (fd == -1) { |
| 1068 | if (forever_multiple) |
| 1069 | file_descs[filenum] = -1; |
| 1070 | detailed_error(0, errno, "%s", filename); |
| 1071 | errors = 1; |
| 1072 | } else { |
| 1073 | if (print_headers) |
| 1074 | write_header(filename, NULL); |
| 1075 | errors = tail(filename, fd, n_units); |
| 1076 | if (forever_multiple) { |
| 1077 | if (fstat(fd, &stats) < 0) { |
| 1078 | detailed_error(0, errno, "%s", filename); |
| 1079 | errors = 1; |
| 1080 | } else if (!S_ISREG(stats.st_mode)) { |
| 1081 | detailed_error(0, 0, |
| 1082 | "%s: cannot follow end of non-regular file", |
| 1083 | filename); |
| 1084 | errors = 1; |
| 1085 | } |
| 1086 | if (errors) { |
| 1087 | close(fd); |
| 1088 | file_descs[filenum] = -1; |
| 1089 | } else { |
| 1090 | file_descs[filenum] = fd; |
| 1091 | file_sizes[filenum] = stats.st_size; |
| 1092 | } |
| 1093 | } else { |
| 1094 | if (close(fd)) { |
| 1095 | detailed_error(0, errno, "%s", filename); |
| 1096 | errors = 1; |
| 1097 | } |
| 1098 | } |
| 1099 | } |
Eric Andersen | abc0f4f | 1999-12-08 23:19:36 +0000 | [diff] [blame] | 1100 | } |
Eric Andersen | abc0f4f | 1999-12-08 23:19:36 +0000 | [diff] [blame] | 1101 | |
Erik Andersen | e49d5ec | 2000-02-08 19:58:47 +0000 | [diff] [blame] | 1102 | return errors; |
Eric Andersen | abc0f4f | 1999-12-08 23:19:36 +0000 | [diff] [blame] | 1103 | } |
| 1104 | |
Erik Andersen | e49d5ec | 2000-02-08 19:58:47 +0000 | [diff] [blame] | 1105 | extern int tail_main(int argc, char **argv) |
Eric Andersen | abc0f4f | 1999-12-08 23:19:36 +0000 | [diff] [blame] | 1106 | { |
Erik Andersen | e49d5ec | 2000-02-08 19:58:47 +0000 | [diff] [blame] | 1107 | int stopit = 0; |
| 1108 | enum header_mode header_mode = multiple_files; |
| 1109 | int exit_status = 0; |
Eric Andersen | abc0f4f | 1999-12-08 23:19:36 +0000 | [diff] [blame] | 1110 | |
Erik Andersen | e49d5ec | 2000-02-08 19:58:47 +0000 | [diff] [blame] | 1111 | /* If from_start, the number of items to skip before printing; otherwise, |
| 1112 | the number of items at the end of the file to print. Initially, -1 |
| 1113 | means the value has not been set. */ |
| 1114 | off_t n_units = -1; |
| 1115 | int n_files; |
| 1116 | char **file; |
| 1117 | |
| 1118 | program_name = argv[0]; |
| 1119 | have_read_stdin = 0; |
| 1120 | count_lines = 1; |
| 1121 | forever = forever_multiple = from_start = print_headers = 0; |
| 1122 | |
| 1123 | /* Parse any options */ |
| 1124 | //fprintf(stderr, "argc=%d, argv=%s\n", argc, *argv); |
| 1125 | while (--argc > 0 && (**(++argv) == '-' || **argv == '+')) { |
| 1126 | if (**argv == '+') { |
| 1127 | from_start = 1; |
| 1128 | } |
| 1129 | stopit = 0; |
| 1130 | while (stopit == 0 && *(++(*argv))) { |
| 1131 | switch (**argv) { |
| 1132 | case 'c': |
| 1133 | count_lines = 0; |
| 1134 | |
| 1135 | if (--argc < 1) { |
| 1136 | usage(tail_usage); |
| 1137 | } |
| 1138 | n_units = getNum(*(++argv)); |
| 1139 | stopit = 1; |
| 1140 | break; |
| 1141 | |
| 1142 | case 'f': |
| 1143 | forever = 1; |
| 1144 | break; |
| 1145 | |
| 1146 | case 'n': |
| 1147 | count_lines = 1; |
| 1148 | |
| 1149 | if (--argc < 1) { |
| 1150 | usage(tail_usage); |
| 1151 | } |
| 1152 | n_units = atol(*(++argv)); |
| 1153 | stopit = 1; |
| 1154 | break; |
| 1155 | |
| 1156 | case 'q': |
| 1157 | header_mode = never; |
| 1158 | break; |
| 1159 | |
| 1160 | case 'v': |
| 1161 | header_mode = always; |
| 1162 | break; |
| 1163 | |
| 1164 | default: |
| 1165 | usage(tail_usage); |
| 1166 | } |
| 1167 | } |
Eric Andersen | 1792f8c | 1999-12-09 06:11:36 +0000 | [diff] [blame] | 1168 | } |
Eric Andersen | 1792f8c | 1999-12-09 06:11:36 +0000 | [diff] [blame] | 1169 | |
Eric Andersen | abc0f4f | 1999-12-08 23:19:36 +0000 | [diff] [blame] | 1170 | |
Erik Andersen | e49d5ec | 2000-02-08 19:58:47 +0000 | [diff] [blame] | 1171 | if (n_units == -1) |
| 1172 | n_units = DEFAULT_N_LINES; |
Eric Andersen | abc0f4f | 1999-12-08 23:19:36 +0000 | [diff] [blame] | 1173 | |
Erik Andersen | e49d5ec | 2000-02-08 19:58:47 +0000 | [diff] [blame] | 1174 | /* To start printing with item N_UNITS from the start of the file, skip |
| 1175 | N_UNITS - 1 items. `tail +0' is actually meaningless, but for Unix |
| 1176 | compatibility it's treated the same as `tail +1'. */ |
| 1177 | if (from_start) { |
| 1178 | if (n_units) |
| 1179 | --n_units; |
Eric Andersen | abc0f4f | 1999-12-08 23:19:36 +0000 | [diff] [blame] | 1180 | } |
Eric Andersen | abc0f4f | 1999-12-08 23:19:36 +0000 | [diff] [blame] | 1181 | |
Erik Andersen | e49d5ec | 2000-02-08 19:58:47 +0000 | [diff] [blame] | 1182 | n_files = argc; |
| 1183 | file = argv; |
Eric Andersen | abc0f4f | 1999-12-08 23:19:36 +0000 | [diff] [blame] | 1184 | |
Erik Andersen | e49d5ec | 2000-02-08 19:58:47 +0000 | [diff] [blame] | 1185 | if (n_files > 1 && forever) { |
| 1186 | forever_multiple = 1; |
| 1187 | forever = 0; |
| 1188 | file_descs = (int *) xmalloc(n_files * sizeof(int)); |
Eric Andersen | abc0f4f | 1999-12-08 23:19:36 +0000 | [diff] [blame] | 1189 | |
Erik Andersen | e49d5ec | 2000-02-08 19:58:47 +0000 | [diff] [blame] | 1190 | file_sizes = (off_t *) xmalloc(n_files * sizeof(off_t)); |
| 1191 | } |
Eric Andersen | abc0f4f | 1999-12-08 23:19:36 +0000 | [diff] [blame] | 1192 | |
Erik Andersen | e49d5ec | 2000-02-08 19:58:47 +0000 | [diff] [blame] | 1193 | if (header_mode == always |
| 1194 | || (header_mode == multiple_files && n_files > 1)) |
| 1195 | print_headers = 1; |
Eric Andersen | abc0f4f | 1999-12-08 23:19:36 +0000 | [diff] [blame] | 1196 | |
Erik Andersen | e49d5ec | 2000-02-08 19:58:47 +0000 | [diff] [blame] | 1197 | if (n_files == 0) { |
| 1198 | exit_status |= tail_file("-", n_units, 0); |
| 1199 | } else { |
| 1200 | int i; |
Eric Andersen | abc0f4f | 1999-12-08 23:19:36 +0000 | [diff] [blame] | 1201 | |
Erik Andersen | e49d5ec | 2000-02-08 19:58:47 +0000 | [diff] [blame] | 1202 | for (i = 0; i < n_files; i++) |
| 1203 | exit_status |= tail_file(file[i], n_units, i); |
Eric Andersen | abc0f4f | 1999-12-08 23:19:36 +0000 | [diff] [blame] | 1204 | |
Erik Andersen | e49d5ec | 2000-02-08 19:58:47 +0000 | [diff] [blame] | 1205 | if (forever_multiple) |
| 1206 | tail_forever(file, n_files); |
| 1207 | } |
Eric Andersen | abc0f4f | 1999-12-08 23:19:36 +0000 | [diff] [blame] | 1208 | |
Erik Andersen | e49d5ec | 2000-02-08 19:58:47 +0000 | [diff] [blame] | 1209 | if (have_read_stdin && close(0) < 0) |
| 1210 | detailed_error(EXIT_FAILURE, errno, "-"); |
| 1211 | if (fclose(stdout) == EOF) |
| 1212 | detailed_error(EXIT_FAILURE, errno, "write error"); |
| 1213 | exit(exit_status == 0 ? EXIT_SUCCESS : EXIT_FAILURE); |
Eric Andersen | abc0f4f | 1999-12-08 23:19:36 +0000 | [diff] [blame] | 1214 | } |
Erik Andersen | 3fe39dc | 2000-01-25 18:13:53 +0000 | [diff] [blame] | 1215 | |
| 1216 | |
| 1217 | #endif |