/* vi: set sw=4 ts=4: */
-#include "internal.h"
-
-/* This file contains _two_ implementations of tail. One is
- * a bit more full featured, but costs 6k. The other (i.e. the
- * SIMPLE_TAIL one) is less capable, but is good enough for about
- * 99% of the things folks want to use tail for, and only costs 2k.
+/*
+ * 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 source tree.
*/
-
-#ifdef BB_FEATURE_SIMPLE_TAIL
-
-/* 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.
-
- 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>.
-
- Rewrote the option parser, removed locales support,
- and generally busyboxed, Erik Andersen <andersen@lineo.com>
-
- Removed superfluous options and associated code ("-c", "-n", "-q").
- Removed "tail -f" support for multiple files.
- Both changes by Friedrich Vedder <fwv@myrtle.lahn.de>.
-
+/* 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 <stdarg.h>
-#include <sys/types.h>
-#include <sys/stat.h>
-#include <fcntl.h>
-#include <ctype.h>
-#define BB_DECLARE_EXTERN
-#define bb_need_help
-#include "messages.c"
-
-
-#define XWRITE(fd, buffer, n_bytes) \
- do { \
- if (n_bytes > 0 && fwrite ((buffer), 1, (n_bytes), stdout) == 0) \
- errorMsg("write error"); \
- } 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, read from the end of one file until killed. */
-static int forever;
-
-/* If nonzero, print filename headers. */
-static int print_headers;
-
-const char tail_usage[] =
- "tail [OPTION] [FILE]...\n"
-#ifndef BB_FEATURE_TRIVIAL_HELP
- "\nPrint last 10 lines of each FILE to standard output.\n"
- "With more than one FILE, precede each with a header giving the\n"
- "file name. With no FILE, or when FILE is -, read standard input.\n\n"
- "Options:\n"
- "\t-n NUM\t\tPrint last NUM lines instead of first 10\n"
-
- "\t-f\t\tOutput data as the file grows. This version\n"
- "\t\t\tof 'tail -f' supports only one file at a time.\n"
-#endif
- ;
-
-
-static void write_header(const char *filename)
-{
- static int first_file = 1;
-
- printf("%s==> %s <==\n", (first_file ? "" : "\n"), filename);
- 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(int fd, long int n_lines, off_t pos)
-{
- 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 = fullRead(fd, buffer, bytes_read);
- if (bytes_read == -1)
- errorMsg("read error");
-
- /* 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;
- }
- }
- /* 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 = fullRead(fd, buffer, BUFSIZ)) > 0);
- if (bytes_read == -1)
- errorMsg("read error");
-
- 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(int fd, long int n_lines)
+//kbuild:lib-$(CONFIG_TAIL) += tail.o
+
+//usage:#define tail_trivial_usage
+//usage: "[OPTIONS] [FILE]..."
+//usage:#define tail_full_usage "\n\n"
+//usage: "Print last 10 lines of each FILE (or stdin) to stdout.\n"
+//usage: "With more than one FILE, precede each with a filename header.\n"
+//usage: "\n -f Print data as file grows"
+//usage: IF_FEATURE_FANCY_TAIL(
+//usage: "\n -s SECONDS Wait SECONDS between reads with -f"
+//usage: )
+//usage: "\n -n N[kbm] Print last N lines"
+//usage: "\n -n +N[kbm] Start on Nth line and print the rest"
+//usage: IF_FEATURE_FANCY_TAIL(
+//usage: "\n -c [+]N[kbm] Print last N bytes"
+//usage: "\n -q Never print headers"
+//usage: "\n -v Always print headers"
+//usage: "\n"
+//usage: "\nN may be suffixed by k (x1024), b (x512), or m (x1024^2)."
+//usage: )
+//usage:
+//usage:#define tail_example_usage
+//usage: "$ tail -n 1 /etc/resolv.conf\n"
+//usage: "nameserver 10.0.0.1\n"
+
+#include "libbb.h"
+
+struct globals {
+ bool from_top;
+ bool exitcode;
+} FIX_ALIASING;
+#define G (*(struct globals*)&bb_common_bufsiz1)
+#define INIT_G() do { } while (0)
+
+static void tail_xprint_header(const char *fmt, const char *filename)
{
- 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 = fullRead(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 (tmp->nbytes == -1)
- errorMsg("read error");
-
- 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;
+ if (fdprintf(STDOUT_FILENO, fmt, filename) < 0)
+ bb_perror_nomsg_and_die();
}
-/* 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(int fd)
+static ssize_t tail_read(int fd, char *buf, size_t count)
{
- char buffer[BUFSIZ];
- int bytes_read;
- long total;
+ ssize_t r;
- total = 0;
- output:
- while ((bytes_read = fullRead(fd, buffer, BUFSIZ)) > 0) {
- XWRITE(STDOUT_FILENO, buffer, bytes_read);
- total += bytes_read;
- }
- if (bytes_read == -1)
- errorMsg("read error");
- if (forever) {
- fflush(stdout);
- sleep(1);
- goto output;
+ r = full_read(fd, buf, count);
+ if (r < 0) {
+ bb_perror_msg(bb_msg_read_error);
+ G.exitcode = EXIT_FAILURE;
}
- return total;
+ return r;
}
-/* Output the last N_LINES lines of file FILENAME open for reading in FD.
- Return 0 if successful, 1 if an error occurred. */
+#define header_fmt_str "\n==> %s <==\n"
-static int tail_lines(const char *filename, int fd, long int n_lines)
+static unsigned eat_num(const char *p)
{
- struct stat stats;
- off_t length;
-
- if (print_headers)
- write_header(filename);
-
- if (fstat(fd, &stats))
- errorMsg("fstat error");
-
- /* 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(fd, n_lines, length))
- return 1;
- dump_remainder(fd);
- } else
- return pipe_lines(fd, n_lines);
-
- return 0;
-}
-
-/* Display the last N_UNITS lines of file FILENAME.
- "-" for FILENAME means the standard input.
- Return 0 if successful, 1 if an error occurred. */
-
-static int tail_file(const char *filename, off_t n_units)
-{
- int fd, errors;
-
- if (!strcmp(filename, "-")) {
- filename = "standard input";
- errors = tail_lines(filename, 0, (long) n_units);
- } else {
- /* Not standard input. */
- fd = open(filename, O_RDONLY);
- if (fd == -1)
- perror(filename);
-
- errors = tail_lines(filename, fd, (long) n_units);
- close(fd);
+ if (*p == '-')
+ p++;
+ else if (*p == '+') {
+ p++;
+ G.from_top = 1;
}
-
- return errors;
+ return xatou_sfx(p, bkm_suffixes);
}
-extern int tail_main(int argc, char **argv)
+int tail_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
+int tail_main(int argc, char **argv)
{
- int exit_status = 0;
- int n_units = DEFAULT_N_LINES;
- int n_tmp, i;
- char opt;
-
- forever = print_headers = 0;
-
- /* parse argv[] */
- for (i = 1; i < argc; i++) {
- if (argv[i][0] == '-') {
- opt = argv[i][1];
- switch (opt) {
- case 'f':
- forever = 1;
- break;
- case 'n':
- n_tmp = 0;
- if (++i < argc)
- n_tmp = atoi(argv[i]);
- if (n_tmp < 1)
- usage(tail_usage);
- n_units = n_tmp;
- break;
- case '-':
- case 'h':
- usage(tail_usage);
- default:
- if ((n_units = atoi(&argv[i][1])) < 1) {
- errorMsg("invalid option -- %c\n", opt);
- usage(tail_usage);
- }
- }
- } else {
- break;
- }
- }
-
- if (i + 1 < argc) {
- if (forever) {
- errorMsg("option -f is invalid with multiple files\n");
- usage(tail_usage);
- }
- print_headers = 1;
- }
-
- if (i >= argc) {
- exit_status |= tail_file("-", n_units);
- } else {
- for (; i < argc; i++)
- exit_status |= tail_file(argv[i], n_units);
+ unsigned count = 10;
+ unsigned sleep_period = 1;
+ const char *str_c, *str_n;
+
+ char *tailbuf;
+ size_t tailbufsize;
+ unsigned header_threshhold = 1;
+ unsigned nfiles;
+ int i, opt;
+
+ int *fds;
+ const char *fmt;
+ int prev_fd;
+
+ INIT_G();
+
+#if ENABLE_INCLUDE_SUSv2 || ENABLE_FEATURE_FANCY_TAIL
+ /* Allow legacy syntax of an initial numeric option without -n. */
+ if (argv[1] && (argv[1][0] == '+' || argv[1][0] == '-')
+ && isdigit(argv[1][1])
+ ) {
+ count = eat_num(argv[1]);
+ argv++;
+ argc--;
}
-
- return(exit_status == 0 ? EXIT_SUCCESS : EXIT_FAILURE);
-}
-
-
-#else
-// Here follows the code for the full featured tail code
-
-
-/* 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.
-
- 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>.
-
- Rewrote the option parser, removed locales support,
- and generally busyboxed, Erik Andersen <andersen@lineo.com>
-
- */
-
-#include "internal.h"
-
-#include <stdio.h>
-#include <stdarg.h>
-#include <assert.h>
-#include <errno.h>
-#include <sys/types.h>
-#include <sys/types.h>
-#include <sys/stat.h>
-#include <fcntl.h>
-#include <ctype.h>
-
-
-
-/* Disable assertions. Some systems have broken assert macros. */
-#define NDEBUG 1
-
-
-static void detailed_error(int i, int errnum, char *fmt, ...)
- __attribute__ ((format (printf, 3, 4)));
-static void detailed_error(int i, int errnum, char *fmt, ...)
-{
- va_list arguments;
-
- va_start(arguments, fmt);
- vfprintf(stderr, fmt, arguments);
- fprintf(stderr, "\n%s\n", strerror(errnum));
- va_end(arguments);
- 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) \
- detailed_error (EXIT_FAILURE, errno, "write error"); \
- } \
- 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
-};
-
-/* The name this program was run with. */
-char *program_name;
-
-/* Nonzero if we have ever read standard input. */
-static int have_read_stdin;
-
-
-static const char tail_usage[] = "tail [OPTION]... [FILE]...\n"
-#ifndef BB_FEATURE_TRIVIAL_HELP
-"\nPrint 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=N[kbm] output the last N bytes\n\
- -f output appended data as the file grows\n\
- -n=N output the last N lines, instead of last 10\n\
- -q never output headers giving file names\n\
- -v always output headers giving file names\n\
-\n\
-If the first character of N (bytes or lines) is a `+', output begins with \n\
-the Nth item from the start of each file, otherwise, print the last N items\n\
-in the file. N bytes may be suffixed by k (x1024), b (x512), or m (1024^2).\n"
+ /* -s NUM, -F imlies -f */
+ IF_FEATURE_FANCY_TAIL(opt_complementary = "s+:Ff";)
+ opt = getopt32(argv, "fc:n:" IF_FEATURE_FANCY_TAIL("qs:vF"),
+ &str_c, &str_n IF_FEATURE_FANCY_TAIL(,&sleep_period));
+#define FOLLOW (opt & 0x1)
+#define COUNT_BYTES (opt & 0x2)
+ //if (opt & 0x1) // -f
+ if (opt & 0x2) count = eat_num(str_c); // -c
+ if (opt & 0x4) count = eat_num(str_n); // -n
+#if ENABLE_FEATURE_FANCY_TAIL
+ /* q: make it impossible for nfiles to be > header_threshhold */
+ if (opt & 0x8) header_threshhold = UINT_MAX; // -q
+ //if (opt & 0x10) // -s
+ if (opt & 0x20) header_threshhold = 0; // -v
+# define FOLLOW_RETRY (opt & 0x40)
+#else
+# define FOLLOW_RETRY 0
#endif
-;
-
-static void write_header(const char *filename, const char *comment)
-{
- static int first_file = 1;
-
- 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)
-{
- 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 = fullRead(fd, buffer, bytes_read);
- if (bytes_read == -1) {
- detailed_error(0, errno, "%s", filename);
- return 1;
+ argc -= optind;
+ argv += optind;
+
+ /* open all the files */
+ fds = xmalloc(sizeof(fds[0]) * (argc + 1));
+ if (!argv[0]) {
+ struct stat statbuf;
+
+ if (fstat(STDIN_FILENO, &statbuf) == 0
+ && S_ISFIFO(statbuf.st_mode)
+ ) {
+ opt &= ~1; /* clear FOLLOW */
+ }
+ argv[0] = (char *) bb_msg_standard_input;
}
-
- /* Count the incomplete line on files that don't end with a newline. */
- if (bytes_read && buffer[bytes_read - 1] != '\n')
- --n_lines;
-
+ nfiles = i = 0;
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;
- }
+ int fd = open_or_warn_stdin(argv[i]);
+ if (fd < 0 && !FOLLOW_RETRY) {
+ G.exitcode = EXIT_FAILURE;
+ continue;
}
- /* 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 = fullRead(fd, buffer, BUFSIZ)) > 0);
- if (bytes_read == -1) {
- detailed_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(int fd, long int n_lines)
-{
- 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 = fullRead(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));
+ fds[nfiles] = fd;
+ argv[nfiles++] = argv[i];
+ } while (++i < argc);
+
+ if (!nfiles)
+ bb_error_msg_and_die("no files");
+
+ /* prepare the buffer */
+ tailbufsize = BUFSIZ;
+ if (!G.from_top && COUNT_BYTES) {
+ if (tailbufsize < count + BUFSIZ) {
+ tailbufsize = count + BUFSIZ;
}
}
- if (tmp->nbytes == -1) {
- detailed_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;
-}
+ /* tail -c1024m REGULAR_FILE doesn't really need 1G mem block.
+ * (In fact, it doesn't need ANY memory). So delay allocation.
+ */
+ tailbuf = NULL;
-/* 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. */
+ /* tail the files */
-static int pipe_bytes(const char *filename, int fd, off_t n_bytes)
-{
- 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 = fullRead(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;
- } 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));
- }
+ fmt = header_fmt_str + 1; /* skip leading newline in the header on the first output */
+ i = 0;
+ do {
+ char *buf;
+ int taillen;
+ int newlines_seen;
+ unsigned seen;
+ int nread;
+ int fd = fds[i];
+
+ if (ENABLE_FEATURE_FANCY_TAIL && fd < 0)
+ continue; /* may happen with -F */
+
+ if (nfiles > header_threshhold) {
+ tail_xprint_header(fmt, argv[i]);
+ fmt = header_fmt_str;
}
- }
- if (tmp->nbytes == -1) {
- detailed_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 = fullRead(fd, buffer, BUFSIZ)) > 0)
- n_bytes -= bytes_read;
- if (bytes_read == -1) {
- detailed_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 = fullRead(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) {
- detailed_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;
-}
-
-/* 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(int fd)
-{
- char buffer[BUFSIZ];
- int bytes_read;
- long total;
-
- total = 0;
- output:
- while ((bytes_read = fullRead(fd, buffer, BUFSIZ)) > 0) {
- XWRITE(STDOUT_FILENO, buffer, bytes_read);
- total += bytes_read;
- }
- if (bytes_read == -1)
- detailed_error(EXIT_FAILURE, errno, "%s", filename);
- if (forever) {
- fflush(stdout);
- sleep(1);
- goto output;
- } else {
- if (forever_multiple)
- fflush(stdout);
- }
-
- return total;
-}
-
-/* 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 void tail_forever(char **names, int nfiles)
-{
- int last;
-
- last = -1;
-
- while (1) {
- int i;
- int changed;
-
- changed = 0;
- for (i = 0; i < nfiles; i++) {
- struct stat stats;
-
- if (file_descs[i] < 0)
- continue;
- if (fstat(file_descs[i], &stats) < 0) {
- detailed_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;
+ if (!G.from_top) {
+ off_t current = lseek(fd, 0, SEEK_END);
+ if (current > 0) {
+ unsigned off;
+ if (COUNT_BYTES) {
+ /* Optimizing count-bytes case if the file is seekable.
+ * Beware of backing up too far.
+ * Also we exclude files with size 0 (because of /proc/xxx) */
+ if (count == 0)
+ continue; /* showing zero bytes is easy :) */
+ current -= count;
+ if (current < 0)
+ current = 0;
+ xlseek(fd, current, SEEK_SET);
+ bb_copyfd_size(fd, STDOUT_FILENO, count);
+ continue;
+ }
+#if 1 /* This is technically incorrect for *LONG* strings, but very useful */
+ /* Optimizing count-lines case if the file is seekable.
+ * We assume the lines are <64k.
+ * (Users complain that tail takes too long
+ * on multi-gigabyte files) */
+ off = (count | 0xf); /* for small counts, be more paranoid */
+ if (off > (INT_MAX / (64*1024)))
+ off = (INT_MAX / (64*1024));
+ current -= off * (64*1024);
+ if (current < 0)
+ current = 0;
+ xlseek(fd, current, SEEK_SET);
+#endif
}
- file_sizes[i] += dump_remainder(file_descs[i]);
}
- /* If none of the files changed size, sleep. */
- if (!changed)
- sleep(1);
- }
-}
-
-/* Output the last N_BYTES bytes of file FILENAME open for reading in FD.
- Return 0 if successful, 1 if an error occurred. */
-
-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)) {
- detailed_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(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 {
- detailed_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;
-}
-
-/* Output the last N_LINES lines of file FILENAME open for reading in FD.
- Return 0 if successful, 1 if an error occurred. */
-
-static int tail_lines(const char *filename, int fd, long int n_lines)
-{
- struct stat stats;
- off_t length;
-
- if (fstat(fd, &stats)) {
- detailed_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(fd);
- } else
- return pipe_lines(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. */
-
-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);
-}
-
-/* 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. */
-
-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) {
- detailed_error(0, errno, "standard input");
- errors = 1;
- } else if (!S_ISREG(stats.st_mode)) {
- detailed_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;
- detailed_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) {
- detailed_error(0, errno, "%s", filename);
- errors = 1;
- } else if (!S_ISREG(stats.st_mode)) {
- detailed_error(0, 0,
- "%s: cannot follow end of non-regular file",
- filename);
- errors = 1;
+ if (!tailbuf)
+ tailbuf = xmalloc(tailbufsize);
+
+ buf = tailbuf;
+ taillen = 0;
+ /* "We saw 1st line/byte".
+ * Used only by +N code ("start from Nth", 1-based): */
+ seen = 1;
+ newlines_seen = 0;
+ while ((nread = tail_read(fd, buf, tailbufsize - taillen)) > 0) {
+ if (G.from_top) {
+ int nwrite = nread;
+ if (seen < count) {
+ /* We need to skip a few more bytes/lines */
+ if (COUNT_BYTES) {
+ nwrite -= (count - seen);
+ seen += nread;
+ } else {
+ char *s = buf;
+ do {
+ --nwrite;
+ if (*s++ == '\n' && ++seen == count) {
+ break;
+ }
+ } while (nwrite);
+ }
}
- if (errors) {
- close(fd);
- file_descs[filenum] = -1;
+ if (nwrite > 0)
+ xwrite(STDOUT_FILENO, buf + nread - nwrite, nwrite);
+ } else if (count) {
+ if (COUNT_BYTES) {
+ taillen += nread;
+ if (taillen > (int)count) {
+ memmove(tailbuf, tailbuf + taillen - count, count);
+ taillen = count;
+ }
} else {
- file_descs[filenum] = fd;
- file_sizes[filenum] = stats.st_size;
- }
- } else {
- if (close(fd)) {
- detailed_error(0, errno, "%s", filename);
- errors = 1;
+ int k = nread;
+ int newlines_in_buf = 0;
+
+ do { /* count '\n' in last read */
+ k--;
+ if (buf[k] == '\n') {
+ newlines_in_buf++;
+ }
+ } while (k);
+
+ if (newlines_seen + newlines_in_buf < (int)count) {
+ newlines_seen += newlines_in_buf;
+ taillen += nread;
+ } else {
+ int extra = (buf[nread-1] != '\n');
+ char *s;
+
+ k = newlines_seen + newlines_in_buf + extra - count;
+ s = tailbuf;
+ while (k) {
+ if (*s == '\n') {
+ k--;
+ }
+ s++;
+ }
+ taillen += nread - (s - tailbuf);
+ memmove(tailbuf, s, taillen);
+ newlines_seen = count - extra;
+ }
+ if (tailbufsize < (size_t)taillen + BUFSIZ) {
+ tailbufsize = taillen + BUFSIZ;
+ tailbuf = xrealloc(tailbuf, tailbufsize);
+ }
}
+ buf = tailbuf + taillen;
}
+ } /* while (tail_read() > 0) */
+ if (!G.from_top) {
+ xwrite(STDOUT_FILENO, tailbuf, taillen);
}
- }
+ } while (++i < nfiles);
+ prev_fd = fds[i-1];
- return errors;
-}
+ tailbuf = xrealloc(tailbuf, BUFSIZ);
-extern int tail_main(int argc, char **argv)
-{
- int stopit = 0;
- enum header_mode header_mode = multiple_files;
- int exit_status = 0;
+ fmt = NULL;
- /* 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;
- int n_files;
- char **file;
+ if (FOLLOW) while (1) {
+ sleep(sleep_period);
- program_name = argv[0];
- have_read_stdin = 0;
- count_lines = 1;
- forever = forever_multiple = from_start = print_headers = 0;
-
- /* Parse any options */
- //fprintf(stderr, "argc=%d, argv=%s\n", argc, *argv);
- while (--argc > 0 && (**(++argv) == '-' || **argv == '+')) {
- if (**argv == '+') {
- from_start = 1;
- }
- stopit = 0;
- while (stopit == 0 && *(++(*argv))) {
- switch (**argv) {
- case 'c':
- count_lines = 0;
-
- if (--argc < 1) {
- usage(tail_usage);
+ i = 0;
+ do {
+ int nread;
+ const char *filename = argv[i];
+ int fd = fds[i];
+
+ if (FOLLOW_RETRY) {
+ struct stat sbuf, fsbuf;
+
+ if (fd < 0
+ || fstat(fd, &fsbuf) < 0
+ || stat(filename, &sbuf) < 0
+ || fsbuf.st_dev != sbuf.st_dev
+ || fsbuf.st_ino != sbuf.st_ino
+ ) {
+ int new_fd;
+
+ if (fd >= 0)
+ close(fd);
+ new_fd = open(filename, O_RDONLY);
+ if (new_fd >= 0) {
+ bb_error_msg("%s has %s; following end of new file",
+ filename, (fd < 0) ? "appeared" : "been replaced"
+ );
+ } else if (fd >= 0) {
+ bb_perror_msg("%s has become inaccessible", filename);
+ }
+ fds[i] = fd = new_fd;
}
- n_units = getNum(*(++argv));
- stopit = 1;
- break;
-
- case 'f':
- forever = 1;
- break;
-
- case 'n':
- count_lines = 1;
-
- if (--argc < 1) {
- usage(tail_usage);
+ }
+ if (ENABLE_FEATURE_FANCY_TAIL && fd < 0)
+ continue;
+ if (nfiles > header_threshhold) {
+ fmt = header_fmt_str;
+ }
+ for (;;) {
+ /* tail -f keeps following files even if they are truncated */
+ struct stat sbuf;
+ /* /proc files report zero st_size, don't lseek them */
+ if (fstat(fd, &sbuf) == 0 && sbuf.st_size > 0) {
+ off_t current = lseek(fd, 0, SEEK_CUR);
+ if (sbuf.st_size < current)
+ xlseek(fd, 0, SEEK_SET);
}
- n_units = atol(*(++argv));
- stopit = 1;
- break;
-
- case 'q':
- header_mode = never;
- break;
- case 'v':
- header_mode = always;
- break;
-
- default:
- usage(tail_usage);
+ nread = tail_read(fd, tailbuf, BUFSIZ);
+ if (nread <= 0)
+ break;
+ if (fmt && (fd != prev_fd)) {
+ tail_xprint_header(fmt, filename);
+ fmt = NULL;
+ prev_fd = fd;
+ }
+ xwrite(STDOUT_FILENO, tailbuf, nread);
}
- }
- }
-
+ } while (++i < nfiles);
+ } /* while (1) */
- 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;
+ if (ENABLE_FEATURE_CLEAN_UP) {
+ free(fds);
+ free(tailbuf);
}
-
- n_files = argc;
- file = argv;
-
- 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)
- detailed_error(EXIT_FAILURE, errno, "-");
- if (fclose(stdout) == EOF)
- detailed_error(EXIT_FAILURE, errno, "write error");
- exit(exit_status == 0 ? EXIT_SUCCESS : EXIT_FAILURE);
+ return G.exitcode;
}
-
-
-#endif
projects / platform / upstream / busybox.git / blobdiff