-/* tail -- output the last part of file(s)
- Copyright (C) 89, 90, 91, 95, 1996 Free Software Foundation, Inc.
-
- 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, 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. */
-
-/* Can display any amount of data, unlike the Unix version, which uses
- a fixed size buffer and therefore can only deliver a limited number
- of lines.
-
- Options:
- -b Tail by N 512-byte blocks.
- -c, --bytes=N[bkm] Tail by N bytes
- [or 512-byte blocks, kilobytes, or megabytes].
- -f, --follow Loop forever trying to read more characters at the
- end of the file, on the assumption that the file
- is growing. Ignored if reading from a pipe.
- -n, --lines=N Tail by N lines.
- -q, --quiet, --silent Never print filename headers.
- -v, --verbose Always print filename headers.
-
- If a number (N) starts with a `+', begin printing with the Nth item
- from the start of each file, instead of from the end.
-
- Reads from standard input if no files are given or when a filename of
- ``-'' is encountered.
- By default, filename headers are printed only more than one file
- is given.
- By default, prints the last 10 lines (tail -n 10).
-
- Original version by Paul Rubin <phr@ocf.berkeley.edu>.
- Extensions by David MacKenzie <djm@gnu.ai.mit.edu>.
- tail -f for multiple files by Ian Lance Taylor <ian@airs.com>. */
-
-#include "internal.h"
+/* vi: set sw=4 ts=4: */
+/*
+ * Mini tail implementation for busybox
+ *
+ * Copyright (C) 2001 by Matt Kraai <kraai@alumni.carnegiemellon.edu>
+ *
+ * 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 */
+
+/* Mar 16, 2003 Manuel Novoa III (mjn3@codepoet.org)
+ *
+ * Pretty much rewritten to fix numerous bugs and reduce realloc() calls.
+ * Bugs fixed (although I may have forgotten one or two... it was pretty bad)
+ * 1) mixing printf/write without fflush()ing stdout
+ * 2) no check that any open files are present
+ * 3) optstring had -q taking an arg
+ * 4) no error checking on write in some cases, and a warning even then
+ * 5) q and s interaction bug
+ * 6) no check for lseek error
+ * 7) lseek attempted when count==0 even if arg was +0 (from top)
+ */
#include <stdio.h>
-#include <assert.h>
-#include <errno.h>
-#include <sys/types.h>
-
-
-/* Disable assertions. Some systems have broken assert macros. */
-#define NDEBUG 1
-
-
-static void error(int i, int errnum, char* fmt, const char *msg)
-{
- fprintf(stderr, fmt, msg);
- perror( errnum);
- exit(i);
-}
-
-
-#define XWRITE(fd, buffer, n_bytes) \
- do \
- { \
- assert ((fd) == 1); \
- assert ((n_bytes) >= 0); \
- if (n_bytes > 0 && fwrite ((buffer), 1, (n_bytes), stdout) == 0) \
- error (EXIT_FAILURE, errno, "write error", NULL); \
- } \
- while (0)
-
-/* Number of items to tail. */
-#define DEFAULT_N_LINES 10
-
-/* Size of atomic reads. */
-#ifndef BUFSIZ
-#define BUFSIZ (512 * 8)
-#endif
-
-/* If nonzero, interpret the numeric argument as the number of lines.
- Otherwise, interpret it as the number of bytes. */
-static int count_lines;
-
-/* If nonzero, read from the end of one file until killed. */
-static int forever;
-
-/* If nonzero, read from the end of multiple files until killed. */
-static int forever_multiple;
-
-/* Array of file descriptors if forever_multiple is 1. */
-static int *file_descs;
-
-/* Array of file sizes if forever_multiple is 1. */
-static off_t *file_sizes;
-
-/* If nonzero, count from start of file instead of end. */
-static int from_start;
-
-/* If nonzero, print filename headers. */
-static int print_headers;
-
-/* When to print the filename banners. */
-enum header_mode
-{
- multiple_files, always, never
+#include <stdlib.h>
+#include <string.h>
+#include <ctype.h>
+#include <unistd.h>
+#include <fcntl.h>
+#include <sys/stat.h>
+#include "busybox.h"
+
+static const struct suffix_mult tail_suffixes[] = {
+ { "b", 512 },
+ { "k", 1024 },
+ { "m", 1048576 },
+ { NULL, 0 }
};
-char *xmalloc ();
-int safe_read ();
-
-/* The name this program was run with. */
-char *program_name;
-
-/* Nonzero if we have ever read standard input. */
-static int have_read_stdin;
-
-/* If nonzero, display usage information and exit. */
-static int show_help;
-
-/* If nonzero, print the version on standard output then exit. */
-static int show_version;
-
-static const char tail_usage[] =
-"tail [OPTION]... [FILE]...\n\
-Print last 10 lines of each FILE to standard output.\n\
-With more than one FILE, precede each with a header giving the file name.\n\
-With no FILE, or when FILE is -, read standard input.\n\
-\n\
- -c, --bytes=N output the last N bytes\n\
- -f, --follow output appended data as the file grows\n\
- -n, --lines=N output the last N lines, instead of last 10\n\
- -q, --quiet, --silent never output headers giving file names\n\
- -v, --verbose always output headers giving file names\n\
- --help display this help and exit\n\
- --version output version information and exit\n\
-\n\
-If the first character of N (the number of bytes or lines) is a `+',\n\
-print beginning with the Nth item from the start of each file, otherwise,\n\
-print the last N items in the file. N may have a multiplier suffix:\n\
-b for 512, k for 1024, m for 1048576 (1 Meg). A first OPTION of -VALUE\n\
-or +VALUE is treated like -n VALUE or -n +VALUE unless VALUE has one of\n\
-the [bkm] suffix multipliers, in which case it is treated like -c VALUE\n\
-or -c +VALUE.\n";
-
-static void
-write_header (const char *filename, const char *comment)
-{
- static int first_file = 1;
+static int status;
- printf ("%s==> %s%s%s <==\n", (first_file ? "" : "\n"), filename,
- (comment ? ": " : ""),
- (comment ? comment : ""));
- first_file = 0;
-}
-
-/* Print the last N_LINES lines from the end of file FD.
- Go backward through the file, reading `BUFSIZ' bytes at a time (except
- probably the first), until we hit the start of the file or have
- read NUMBER newlines.
- POS starts out as the length of the file (the offset of the last
- byte of the file + 1).
- Return 0 if successful, 1 if an error occurred. */
-
-static int
-file_lines (const char *filename, int fd, long int n_lines, off_t pos)
+static void tail_xprint_header(const char *fmt, const char *filename)
{
- char buffer[BUFSIZ];
- int bytes_read;
- int i; /* Index into `buffer' for scanning. */
-
- if (n_lines == 0)
- return 0;
-
- /* Set `bytes_read' to the size of the last, probably partial, buffer;
- 0 < `bytes_read' <= `BUFSIZ'. */
- bytes_read = pos % BUFSIZ;
- if (bytes_read == 0)
- bytes_read = BUFSIZ;
- /* Make `pos' a multiple of `BUFSIZ' (0 if the file is short), so that all
- reads will be on block boundaries, which might increase efficiency. */
- pos -= bytes_read;
- lseek (fd, pos, SEEK_SET);
- bytes_read = safe_read (fd, buffer, bytes_read);
- if (bytes_read == -1)
- {
- error (0, errno, "%s", filename);
- return 1;
- }
-
- /* Count the incomplete line on files that don't end with a newline. */
- if (bytes_read && buffer[bytes_read - 1] != '\n')
- --n_lines;
-
- do
- {
- /* Scan backward, counting the newlines in this bufferfull. */
- for (i = bytes_read - 1; i >= 0; i--)
- {
- /* Have we counted the requested number of newlines yet? */
- if (buffer[i] == '\n' && n_lines-- == 0)
- {
- /* If this newline wasn't the last character in the buffer,
- print the text after it. */
- if (i != bytes_read - 1)
- XWRITE (STDOUT_FILENO, &buffer[i + 1], bytes_read - (i + 1));
- return 0;
- }
+ /* 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();
}
- /* Not enough newlines in that bufferfull. */
- if (pos == 0)
- {
- /* Not enough lines in the file; print the entire file. */
- lseek (fd, (off_t) 0, SEEK_SET);
- return 0;
- }
- pos -= BUFSIZ;
- lseek (fd, pos, SEEK_SET);
- }
- while ((bytes_read = safe_read (fd, buffer, BUFSIZ)) > 0);
- if (bytes_read == -1)
- {
- error (0, errno, "%s", filename);
- return 1;
- }
- return 0;
}
-/* Print the last N_LINES lines from the end of the standard input,
- open for reading as pipe FD.
- Buffer the text as a linked list of LBUFFERs, adding them as needed.
- Return 0 if successful, 1 if an error occured. */
-
-static int
-pipe_lines (const char *filename, int fd, long int n_lines)
+/* len should probably be size_t */
+static void tail_xbb_full_write(const char *buf, size_t len)
{
- struct linebuffer
- {
- int nbytes, nlines;
- char buffer[BUFSIZ];
- struct linebuffer *next;
- };
- typedef struct linebuffer LBUFFER;
- LBUFFER *first, *last, *tmp;
- int i; /* Index into buffers. */
- int total_lines = 0; /* Total number of newlines in all buffers. */
- int errors = 0;
-
- first = last = (LBUFFER *) xmalloc (sizeof (LBUFFER));
- first->nbytes = first->nlines = 0;
- first->next = NULL;
- tmp = (LBUFFER *) xmalloc (sizeof (LBUFFER));
-
- /* Input is always read into a fresh buffer. */
- while ((tmp->nbytes = safe_read (fd, tmp->buffer, BUFSIZ)) > 0)
- {
- tmp->nlines = 0;
- tmp->next = NULL;
-
- /* Count the number of newlines just read. */
- for (i = 0; i < tmp->nbytes; i++)
- if (tmp->buffer[i] == '\n')
- ++tmp->nlines;
- total_lines += tmp->nlines;
-
- /* If there is enough room in the last buffer read, just append the new
- one to it. This is because when reading from a pipe, `nbytes' can
- often be very small. */
- if (tmp->nbytes + last->nbytes < BUFSIZ)
- {
- memcpy (&last->buffer[last->nbytes], tmp->buffer, tmp->nbytes);
- last->nbytes += tmp->nbytes;
- last->nlines += tmp->nlines;
- }
- else
- {
- /* If there's not enough room, link the new buffer onto the end of
- the list, then either free up the oldest buffer for the next
- read if that would leave enough lines, or else malloc a new one.
- Some compaction mechanism is possible but probably not
- worthwhile. */
- last = last->next = tmp;
- if (total_lines - first->nlines > n_lines)
- {
- tmp = first;
- total_lines -= first->nlines;
- first = first->next;
- }
- else
- tmp = (LBUFFER *) xmalloc (sizeof (LBUFFER));
+ /* 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();
}
- }
- if (tmp->nbytes == -1)
- {
- error (0, errno, "%s", filename);
- errors = 1;
- free ((char *) tmp);
- goto free_lbuffers;
- }
-
- free ((char *) tmp);
-
- /* This prevents a core dump when the pipe contains no newlines. */
- if (n_lines == 0)
- goto free_lbuffers;
-
- /* Count the incomplete line on files that don't end with a newline. */
- if (last->buffer[last->nbytes - 1] != '\n')
- {
- ++last->nlines;
- ++total_lines;
- }
-
- /* Run through the list, printing lines. First, skip over unneeded
- buffers. */
- for (tmp = first; total_lines - tmp->nlines > n_lines; tmp = tmp->next)
- total_lines -= tmp->nlines;
-
- /* Find the correct beginning, then print the rest of the file. */
- if (total_lines > n_lines)
- {
- char *cp;
-
- /* Skip `total_lines' - `n_lines' newlines. We made sure that
- `total_lines' - `n_lines' <= `tmp->nlines'. */
- cp = tmp->buffer;
- for (i = total_lines - n_lines; i; --i)
- while (*cp++ != '\n')
- /* Do nothing. */ ;
- i = cp - tmp->buffer;
- }
- else
- i = 0;
- XWRITE (STDOUT_FILENO, &tmp->buffer[i], tmp->nbytes - i);
-
- for (tmp = tmp->next; tmp; tmp = tmp->next)
- XWRITE (STDOUT_FILENO, tmp->buffer, tmp->nbytes);
-
-free_lbuffers:
- while (first)
- {
- tmp = first->next;
- free ((char *) first);
- first = tmp;
- }
- return errors;
}
-/* Print the last N_BYTES characters from the end of pipe FD.
- This is a stripped down version of pipe_lines.
- Return 0 if successful, 1 if an error occurred. */
-
-static int
-pipe_bytes (const char *filename, int fd, off_t n_bytes)
+static ssize_t tail_read(int fd, char *buf, size_t count)
{
- struct charbuffer
- {
- int nbytes;
- char buffer[BUFSIZ];
- struct charbuffer *next;
- };
- typedef struct charbuffer CBUFFER;
- CBUFFER *first, *last, *tmp;
- int i; /* Index into buffers. */
- int total_bytes = 0; /* Total characters in all buffers. */
- int errors = 0;
-
- first = last = (CBUFFER *) xmalloc (sizeof (CBUFFER));
- first->nbytes = 0;
- first->next = NULL;
- tmp = (CBUFFER *) xmalloc (sizeof (CBUFFER));
-
- /* Input is always read into a fresh buffer. */
- while ((tmp->nbytes = safe_read (fd, tmp->buffer, BUFSIZ)) > 0)
- {
- tmp->next = NULL;
-
- total_bytes += tmp->nbytes;
- /* If there is enough room in the last buffer read, just append the new
- one to it. This is because when reading from a pipe, `nbytes' can
- often be very small. */
- if (tmp->nbytes + last->nbytes < BUFSIZ)
- {
- memcpy (&last->buffer[last->nbytes], tmp->buffer, tmp->nbytes);
- last->nbytes += tmp->nbytes;
+ 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(bb_msg_read_error);
+ status = EXIT_FAILURE;
}
- else
- {
- /* If there's not enough room, link the new buffer onto the end of
- the list, then either free up the oldest buffer for the next
- read if that would leave enough characters, or else malloc a new
- one. Some compaction mechanism is possible but probably not
- worthwhile. */
- last = last->next = tmp;
- if (total_bytes - first->nbytes > n_bytes)
- {
- tmp = first;
- total_bytes -= first->nbytes;
- first = first->next;
- }
- else
- {
- tmp = (CBUFFER *) xmalloc (sizeof (CBUFFER));
- }
- }
- }
- if (tmp->nbytes == -1)
- {
- error (0, errno, "%s", filename);
- errors = 1;
- free ((char *) tmp);
- goto free_cbuffers;
- }
-
- free ((char *) tmp);
-
- /* Run through the list, printing characters. First, skip over unneeded
- buffers. */
- for (tmp = first; total_bytes - tmp->nbytes > n_bytes; tmp = tmp->next)
- total_bytes -= tmp->nbytes;
-
- /* Find the correct beginning, then print the rest of the file.
- We made sure that `total_bytes' - `n_bytes' <= `tmp->nbytes'. */
- if (total_bytes > n_bytes)
- i = total_bytes - n_bytes;
- else
- i = 0;
- XWRITE (STDOUT_FILENO, &tmp->buffer[i], tmp->nbytes - i);
-
- for (tmp = tmp->next; tmp; tmp = tmp->next)
- XWRITE (STDOUT_FILENO, tmp->buffer, tmp->nbytes);
-
-free_cbuffers:
- while (first)
- {
- tmp = first->next;
- free ((char *) first);
- first = tmp;
- }
- return errors;
-}
-
-/* Skip N_BYTES characters from the start of pipe FD, and print
- any extra characters that were read beyond that.
- Return 1 on error, 0 if ok. */
-
-static int
-start_bytes (const char *filename, int fd, off_t n_bytes)
-{
- char buffer[BUFSIZ];
- int bytes_read = 0;
-
- while (n_bytes > 0 && (bytes_read = safe_read (fd, buffer, BUFSIZ)) > 0)
- n_bytes -= bytes_read;
- if (bytes_read == -1)
- {
- error (0, errno, "%s", filename);
- return 1;
- }
- else if (n_bytes < 0)
- XWRITE (STDOUT_FILENO, &buffer[bytes_read + n_bytes], -n_bytes);
- return 0;
-}
-
-/* Skip N_LINES lines at the start of file or pipe FD, and print
- any extra characters that were read beyond that.
- Return 1 on error, 0 if ok. */
-static int
-start_lines (const char *filename, int fd, long int n_lines)
-{
- char buffer[BUFSIZ];
- int bytes_read = 0;
- int bytes_to_skip = 0;
-
- while (n_lines && (bytes_read = safe_read (fd, buffer, BUFSIZ)) > 0)
- {
- bytes_to_skip = 0;
- while (bytes_to_skip < bytes_read)
- if (buffer[bytes_to_skip++] == '\n' && --n_lines == 0)
- break;
- }
- if (bytes_read == -1)
- {
- error (0, errno, "%s", filename);
- return 1;
- }
- else if (bytes_to_skip < bytes_read)
- {
- XWRITE (STDOUT_FILENO, &buffer[bytes_to_skip],
- bytes_read - bytes_to_skip);
- }
- return 0;
+ return r;
}
-/* Display file FILENAME from the current position in FD to the end.
- If `forever' is nonzero, keep reading from the end of the file
- until killed. Return the number of bytes read from the file. */
-
-static long
-dump_remainder (const char *filename, int fd)
-{
- char buffer[BUFSIZ];
- int bytes_read;
- long total;
-
- total = 0;
-output:
- while ((bytes_read = safe_read (fd, buffer, BUFSIZ)) > 0)
- {
- XWRITE (STDOUT_FILENO, buffer, bytes_read);
- total += bytes_read;
- }
- if (bytes_read == -1)
- error (EXIT_FAILURE, errno, "%s", filename);
- if (forever)
- {
- fflush (stdout);
- sleep (1);
- goto output;
- }
- else
- {
- if (forever_multiple)
- fflush (stdout);
- }
-
- return total;
-}
+static const char tail_opts[] =
+ "fn:c:"
+#if ENABLE_FEATURE_FANCY_TAIL
+ "qs:v"
+#endif
+ ;
-/* Tail NFILES (>1) files forever until killed. The file names are in
- NAMES. The open file descriptors are in `file_descs', and the size
- at which we stopped tailing them is in `file_sizes'. We loop over
- each of them, doing an fstat to see if they have changed size. If
- none of them have changed size in one iteration, we sleep for a
- second and try again. We do this until the user interrupts us. */
+static const char header_fmt[] = "\n==> %s <==\n";
-static void
-tail_forever (char **names, int nfiles)
+int tail_main(int argc, char **argv)
{
- int last;
-
- last = -1;
-
- while (1)
- {
- int i;
- int changed;
-
- changed = 0;
- for (i = 0; i < nfiles; i++)
+ 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;
+
+#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))))
{
- struct stat stats;
-
- if (file_descs[i] < 0)
- continue;
- if (fstat (file_descs[i], &stats) < 0)
- {
- error (0, errno, "%s", names[i]);
- file_descs[i] = -1;
- continue;
- }
- if (stats.st_size == file_sizes[i])
- continue;
-
- /* This file has changed size. Print out what we can, and
- then keep looping. */
-
- changed = 1;
-
- if (stats.st_size < file_sizes[i])
- {
- write_header (names[i], "file truncated");
- last = i;
- lseek (file_descs[i], stats.st_size, SEEK_SET);
- file_sizes[i] = stats.st_size;
- continue;
- }
-
- if (i != last)
- {
- if (print_headers)
- write_header (names[i], NULL);
- last = i;
- }
- file_sizes[i] += dump_remainder (names[i], file_descs[i]);
+ optind = 2;
+ optarg = argv[1];
+ goto GET_COUNT;
}
+#endif
- /* If none of the files changed size, sleep. */
- if (! changed)
- sleep (1);
- }
-}
+ while ((opt = getopt(argc, argv, tail_opts)) > 0) {
+ switch (opt) {
+ case 'f':
+ follow = 1;
+ break;
+ case 'c':
+ count_bytes = 1;
+ /* FALLS THROUGH */
+ case 'n':
+#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;
+#if ENABLE_FEATURE_FANCY_TAIL
+ case 'q':
+ header_threshhold = INT_MAX;
+ break;
+ case 's':
+ sleep_period =bb_xgetularg10_bnd(optarg, 0, UINT_MAX);
+ break;
+ case 'v':
+ header_threshhold = 0;
+ break;
+#endif
+ default:
+ bb_show_usage();
+ }
+ }
-/* Output the last N_BYTES bytes of file FILENAME open for reading in FD.
- Return 0 if successful, 1 if an error occurred. */
+ /* open all the files */
+ fds = (int *)xmalloc(sizeof(int) * (argc - optind + 1));
-static int
-tail_bytes (const char *filename, int fd, off_t n_bytes)
-{
- struct stat stats;
-
- /* FIXME: resolve this like in dd.c. */
- /* Use fstat instead of checking for errno == ESPIPE because
- lseek doesn't work on some special files but doesn't return an
- error, either. */
- if (fstat (fd, &stats))
- {
- error (0, errno, "%s", filename);
- return 1;
- }
-
- if (from_start)
- {
- if (S_ISREG (stats.st_mode))
- lseek (fd, n_bytes, SEEK_CUR);
- else if (start_bytes (filename, fd, n_bytes))
- return 1;
- dump_remainder (filename, fd);
- }
- else
- {
- if (S_ISREG (stats.st_mode))
- {
- off_t current_pos, end_pos;
- size_t bytes_remaining;
-
- if ((current_pos = lseek (fd, (off_t) 0, SEEK_CUR)) != -1
- && (end_pos = lseek (fd, (off_t) 0, SEEK_END)) != -1)
- {
- off_t diff;
- /* Be careful here. The current position may actually be
- beyond the end of the file. */
- bytes_remaining = (diff = end_pos - current_pos) < 0 ? 0 : diff;
- }
- else
- {
- error (0, errno, "%s", filename);
- return 1;
- }
-
- if (bytes_remaining <= n_bytes)
- {
- /* From the current position to end of file, there are no
- more bytes than have been requested. So reposition the
- file pointer to the incoming current position and print
- everything after that. */
- lseek (fd, current_pos, SEEK_SET);
- }
- else
- {
- /* There are more bytes remaining than were requested.
- Back up. */
- lseek (fd, -n_bytes, SEEK_END);
- }
- dump_remainder (filename, fd);
- }
- else
- return pipe_bytes (filename, fd, n_bytes);
- }
- return 0;
-}
+ argv += optind;
+ nfiles = i = 0;
-/* Output the last N_LINES lines of file FILENAME open for reading in FD.
- Return 0 if successful, 1 if an error occurred. */
+ if ((argc -= optind) == 0) {
+ struct stat statbuf;
-static int
-tail_lines (const char *filename, int fd, long int n_lines)
-{
- struct stat stats;
- off_t length;
-
- if (fstat (fd, &stats))
- {
- error (0, errno, "%s", filename);
- return 1;
- }
-
- if (from_start)
- {
- if (start_lines (filename, fd, n_lines))
- return 1;
- dump_remainder (filename, fd);
- }
- else
- {
- /* Use file_lines only if FD refers to a regular file with
- its file pointer positioned at beginning of file. */
- /* FIXME: adding the lseek conjunct is a kludge.
- Once there's a reasonable test suite, fix the true culprit:
- file_lines. file_lines shouldn't presume that the input
- file pointer is initially positioned to beginning of file. */
- if (S_ISREG (stats.st_mode)
- && lseek (fd, (off_t) 0, SEEK_CUR) == (off_t) 0)
- {
- length = lseek (fd, (off_t) 0, SEEK_END);
- if (length != 0 && file_lines (filename, fd, n_lines, length))
- return 1;
- dump_remainder (filename, fd);
+ if (!fstat(STDIN_FILENO, &statbuf) && S_ISFIFO(statbuf.st_mode)) {
+ follow = 0;
+ }
+ /* --argv; */
+ *argv = (char *) bb_msg_standard_input;
+ goto DO_STDIN;
}
- else
- return pipe_lines (filename, fd, n_lines);
- }
- return 0;
-}
-/* Display the last N_UNITS units of file FILENAME, open for reading
- in FD.
- Return 0 if successful, 1 if an error occurred. */
+ 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);
-static int
-tail (const char *filename, int fd, off_t n_units)
-{
- if (count_lines)
- return tail_lines (filename, fd, (long) n_units);
- else
- return tail_bytes (filename, fd, n_units);
-}
+ if (!nfiles) {
+ bb_error_msg_and_die("no files");
+ }
-/* Display the last N_UNITS units of file FILENAME.
- "-" for FILENAME means the standard input.
- FILENUM is this file's index in the list of files the user gave.
- Return 0 if successful, 1 if an error occurred. */
+ tailbufsize = BUFSIZ;
-static int
-tail_file (const char *filename, off_t n_units, int filenum)
-{
- int fd, errors;
- struct stat stats;
-
- if (!strcmp (filename, "-")
- {
- have_read_stdin = 1;
- filename = "standard input";
- if (print_headers)
- write_header (filename, NULL);
- errors = tail (filename, 0, n_units);
- if (forever_multiple)
- {
- if (fstat (0, &stats) < 0)
- {
- error (0, errno, "standard input");
- errors = 1;
- }
- else if (!S_ISREG (stats.st_mode))
- {
- error (0, 0,
- "standard input: cannot follow end of non-regular file");
- errors = 1;
- }
- if (errors)
- file_descs[filenum] = -1;
- else
- {
- file_descs[filenum] = 0;
- file_sizes[filenum] = stats.st_size;
- }
- }
- }
- else
- {
- /* Not standard input. */
- fd = open (filename, O_RDONLY);
- if (fd == -1)
- {
- if (forever_multiple)
- file_descs[filenum] = -1;
- error (0, errno, "%s", filename);
- errors = 1;
- }
- else
- {
- if (print_headers)
- write_header (filename, NULL);
- errors = tail (filename, fd, n_units);
- if (forever_multiple)
- {
- if (fstat (fd, &stats) < 0)
- {
- error (0, errno, "%s", filename);
- errors = 1;
- }
- else if (!S_ISREG (stats.st_mode))
- {
- error (0, 0, "%s: cannot follow end of non-regular file",
- filename);
- errors = 1;
- }
- if (errors)
- {
- close (fd);
- file_descs[filenum] = -1;
+ /* tail the files */
+ 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;
}
- else
- {
- file_descs[filenum] = fd;
- file_sizes[filenum] = stats.st_size;
+ }
+
+ 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;
}
- }
- else
- {
- if (close (fd))
- {
- error (0, errno, "%s", filename);
- errors = 1;
+
+ if (nfiles > header_threshhold) {
+ tail_xprint_header(fmt, argv[i]);
+ fmt = header_fmt;
}
- }
- }
- }
- return errors;
-}
+ buf = tailbuf;
+ taillen = 0;
+ seen = 1;
+ newline = 0;
+
+ while ((nread = tail_read(fds[i], buf, tailbufsize-taillen)) > 0) {
+ if (from_top) {
+ 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);
+ }
+ }
+ 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;
+ }
+ } else {
+ int k = nread;
+ int nbuf = 0;
+
+ while (k) {
+ --k;
+ if (buf[k] == '\n') {
+ ++nbuf;
+ }
+ }
+
+ if (newline + nbuf < count) {
+ newline += nbuf;
+ taillen += nread;
+
+ } else {
+ int extra = 0;
+ if (buf[nread-1] != '\n') {
+ extra = 1;
+ }
+
+ 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;
+ }
+ }
-extern int
-tai_main (int argc, char **argv)
-{
- enum header_mode header_mode = multiple_files;
- int exit_status = 0;
- /* If from_start, the number of items to skip before printing; otherwise,
- the number of items at the end of the file to print. Initially, -1
- means the value has not been set. */
- off_t n_units = -1;
- long int tmp_long;
- int c; /* Option character. */
- int n_files;
- char **file;
-
- program_name = argv[0];
- have_read_stdin = 0;
- count_lines = 1;
- forever = forever_multiple = from_start = print_headers = 0;
-
- if (argc > 1
- && ((argv[1][0] == '-' && ISDIGIT (argv[1][1]))
- || (argv[1][0] == '+' && (ISDIGIT (argv[1][1])
- || argv[1][1] == 0))))
- {
- /* Old option syntax: a dash or plus, one or more digits (zero digits
- are acceptable with a plus), and one or more option letters. */
- if (argv[1][0] == '+')
- from_start = 1;
- if (argv[1][1] != '\0')
- {
- strtol_error s_err;
- char *p;
-
- s_err = xstrtol (++argv[1], &p, 0, &tmp_long, "bkm");
- n_units = tmp_long;
- if (s_err == LONGINT_OVERFLOW)
- {
- STRTOL_FATAL_ERROR (argv[1], "argument", s_err);
- }
-
- /* If a [bkm] suffix was given then count bytes, not lines. */
- if (p[-1] == 'b' || p[-1] == 'k' || p[-1] == 'm')
- count_lines = 0;
-
- /* Parse any appended option letters. */
- while (*p)
- {
- switch (*p)
- {
- case 'c':
- /* Interpret N_UNITS as # of bytes. */
- count_lines = 0;
- break;
-
- case 'f':
- forever = 1;
- break;
-
- case 'l':
- count_lines = 1;
- break;
-
- case 'q':
- header_mode = never;
- break;
-
- case 'v':
- header_mode = always;
- break;
-
- default:
- error (0, 0, "unrecognized option '%c'", *p);
- usage (tail_usage);
+ if (!from_top) {
+ tail_xbb_full_write(tailbuf, taillen);
}
- ++p;
- }
+
+ taillen = 0;
+ } while (++i < nfiles);
+
+ buf = xrealloc(tailbuf, BUFSIZ);
+
+ fmt = NULL;
+
+ while (follow) {
+ sleep(sleep_period);
+ i = 0;
+ do {
+ if (nfiles > header_threshhold) {
+ fmt = header_fmt;
+ }
+ 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);
}
- /* Make the options we just parsed invisible to getopt. */
- argv[1] = argv[0];
- argv++;
- argc--;
- }
-
- if (show_version)
- {
- printf ("tail - %s\n", PACKAGE_VERSION);
- exit (EXIT_SUCCESS);
- }
-
- if (show_help)
- usage (tail_usage);
-
- if (n_units == -1)
- n_units = DEFAULT_N_LINES;
-
- /* To start printing with item N_UNITS from the start of the file, skip
- N_UNITS - 1 items. `tail +0' is actually meaningless, but for Unix
- compatibility it's treated the same as `tail +1'. */
- if (from_start)
- {
- if (n_units)
- --n_units;
- }
-
- n_files = argc - optind;
- file = argv + optind;
-
- if (n_files > 1 && forever)
- {
- forever_multiple = 1;
- forever = 0;
- file_descs = (int *) xmalloc (n_files * sizeof (int));
- file_sizes = (off_t *) xmalloc (n_files * sizeof (off_t));
- }
-
- if (header_mode == always
- || (header_mode == multiple_files && n_files > 1))
- print_headers = 1;
-
- if (n_files == 0)
- {
- exit_status |= tail_file ("-", n_units, 0);
- }
- else
- {
- int i;
- for (i = 0; i < n_files; i++)
- exit_status |= tail_file (file[i], n_units, i);
-
- if (forever_multiple)
- tail_forever (file, n_files);
- }
-
- if (have_read_stdin && close (0) < 0)
- error (EXIT_FAILURE, errno, "-");
- if (fclose (stdout) == EOF)
- error (EXIT_FAILURE, errno, "write error");
- exit (exit_status == 0 ? EXIT_SUCCESS : EXIT_FAILURE);
+
+ return status;
}
projects / oweals / busybox.git / blobdiff