320 lines
6.5 KiB
C
320 lines
6.5 KiB
C
/* vi: set sw=4 ts=4: */
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/* tail -- output the last part of file(s)
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Copyright (C) 89, 90, 91, 95, 1996 Free Software Foundation, Inc.
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2, or (at your option)
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any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
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Original version by Paul Rubin <phr@ocf.berkeley.edu>.
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Extensions by David MacKenzie <djm@gnu.ai.mit.edu>.
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tail -f for multiple files by Ian Lance Taylor <ian@airs.com>.
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Rewrote the option parser, removed locales support,
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and generally busyboxed, Erik Andersen <andersen@lineo.com>
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Removed superfluous options and associated code ("-c", "-n", "-q").
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Removed "tail -f" support for multiple files.
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Both changes by Friedrich Vedder <fwv@myrtle.lahn.de>.
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Compleate Rewrite to correctly support "-NUM", "+NUM", and "-s" by
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E.Allen Soard (esp@espsw.net).
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*/
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#include <sys/types.h>
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#include <fcntl.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <unistd.h>
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#include <string.h>
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#include <getopt.h>
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#include "busybox.h"
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#define STDIN "standard input"
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#define LINES 0
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#define BYTES 1
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static int n_files = 0;
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static char **files = NULL;
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static char * buffer;
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static ssize_t bytes_read=0;
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static ssize_t bs;
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static ssize_t filelocation=0;
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static char pip;
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#ifdef BB_FEATURE_SIMPLE_TAIL
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static const char unit_type=LINES;
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#else
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static char unit_type=LINES;
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static char verbose = 0;
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#endif
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static off_t units=0;
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static int tail_stream(int fd)
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{
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ssize_t startpoint;
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ssize_t endpoint=0;
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ssize_t count=0;
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ssize_t filesize=0;
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int direction=1;
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filelocation=0;
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startpoint=bs=BUFSIZ;
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filesize=lseek(fd, -1, SEEK_END)+1;
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pip=(filesize<=0);
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if(units>=0)
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lseek(fd,0,SEEK_SET);
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else {
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direction=-1;
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count=1;
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}
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while(units != 0) {
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if (pip) {
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char * line;
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ssize_t f_size=0;
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bs=BUFSIZ;
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line=xmalloc(bs);
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while(1) {
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bytes_read=read(fd,line,bs);
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if(bytes_read<=0)
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break;
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buffer=xrealloc(buffer,f_size+bytes_read);
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memcpy(&buffer[f_size],line,bytes_read);
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filelocation=f_size+=bytes_read;
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}
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bs=f_size;
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if(direction<0)
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bs--;
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if (line)
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free(line);
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} else {
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filelocation = lseek(fd, 0, SEEK_CUR);
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if(direction<0) {
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if(filelocation<bs)
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bs=filelocation;
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filelocation = lseek(fd, -bs, SEEK_CUR);
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}
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bytes_read = read(fd, buffer, bs);
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if (bytes_read <= 0)
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break;
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bs=bytes_read;
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}
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startpoint=bs;
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if(direction>0) {
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endpoint=startpoint;
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startpoint=0;
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}
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for(;startpoint!=endpoint;startpoint+=direction) {
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#ifndef BB_FEATURE_SIMPLE_TAIL
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if(unit_type==BYTES)
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count++;
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else
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#endif
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if(buffer[startpoint-1]=='\n')
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count++;
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if (!pip)
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filelocation=lseek(fd,0,SEEK_CUR);
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if(count==units*direction)
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break;
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}
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if((count==units*direction) | pip)
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break;
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if(direction<0){
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filelocation = lseek(fd, -bytes_read, SEEK_CUR);
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if(filelocation==0)
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break;
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}
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}
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if(pip && (direction<0))
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bs++;
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bytes_read=bs-startpoint;
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memcpy(&buffer[0],&buffer[startpoint],bytes_read);
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return 0;
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}
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void add_file(char *name)
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{
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++n_files;
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files = xrealloc(files, n_files);
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files[n_files - 1] = (char *) xmalloc(strlen(name) + 1);
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strcpy(files[n_files - 1], name);
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}
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int tail_main(int argc, char **argv)
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{
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int show_headers = 1;
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int test;
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int opt;
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char follow=0;
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int sleep_int=1;
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int *fd;
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opterr = 0;
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while ((opt=getopt(argc,argv,"c:fhn:s:q:v")) >0) {
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switch (opt) {
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#ifndef BB_FEATURE_SIMPLE_TAIL
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case 'c':
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unit_type = BYTES;
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test = atoi(optarg);
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if(test==0)
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usage(tail_usage);
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if(optarg[strlen(optarg)-1]>'9') {
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switch (optarg[strlen(optarg)-1]) {
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case 'b':
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test *= 512;
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break;
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case 'k':
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test *= 1024;
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break;
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case 'm':
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test *= (1024 * 1024);
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break;
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default:
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fprintf(stderr,"Size must be b,k, or m.");
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usage(tail_usage);
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}
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}
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if(optarg[0]=='+')
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units=test+1;
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else
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units=-(test+1);
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break;
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case 'q':
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show_headers = 0;
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break;
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case 's':
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sleep_int = atoi(optarg);
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if(sleep_int<1)
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sleep_int=1;
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break;
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case 'v':
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verbose = 1;
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break;
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#endif
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case 'f':
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follow = 1;
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break;
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case 'h':
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usage(tail_usage);
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break;
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case 'n':
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test = atoi(optarg);
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if (test) {
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if (optarg[0] == '+')
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units = test;
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else
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units = -(test+1);
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} else
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usage(tail_usage);
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break;
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default:
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error_msg("\nUnknown arg: %c.\n\n",optopt);
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usage(tail_usage);
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}
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}
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while (optind <= argc) {
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if(optind==argc) {
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if (n_files==0)
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add_file(STDIN);
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else
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break;
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}else {
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if (!strcmp(argv[optind], "-")) {
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add_file(STDIN);
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} else {
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add_file(argv[optind]);
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}
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optind++;
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}
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}
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if(units==0)
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units=-11;
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if(units>0)
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units--;
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fd=xmalloc(sizeof(int)*n_files);
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if (n_files == 1)
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#ifndef BB_FEATURE_SIMPLE_TAIL
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if (!verbose)
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#endif
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show_headers = 0;
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buffer=xmalloc(BUFSIZ);
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for (test = 0; test < n_files; test++) {
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if (show_headers)
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printf("==> %s <==\n", files[test]);
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if (!strcmp(files[test], STDIN))
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fd[test] = 0;
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else
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fd[test] = open(files[test], O_RDONLY);
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if (fd[test] == -1)
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error_msg_and_die("Unable to open file %s.\n", files[test]);
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tail_stream(fd[test]);
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bs=BUFSIZ;
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while (1) {
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if((filelocation>0 || pip)){
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write(1,buffer,bytes_read);
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}
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bytes_read = read(fd[test], buffer, bs);
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filelocation+=bytes_read;
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if (bytes_read <= 0) {
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break;
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}
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usleep(sleep_int * 1000);
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}
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if(n_files>1)
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printf("\n");
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}
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while(1){
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for (test = 0; test < n_files; test++) {
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if(!follow){
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close(fd[test]);
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continue;
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} else {
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sleep(sleep_int);
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bytes_read = read(fd[test], buffer, bs);
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if(bytes_read>0) {
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if (show_headers)
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printf("==> %s <==\n", files[test]);
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write(1,buffer,bytes_read);
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if(n_files>1)
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printf("\n");
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}
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}
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}
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if(!follow)
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break;
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}
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if (fd)
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free(fd);
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if (buffer)
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free(buffer);
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if(files)
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free(files);
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return 0;
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}
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/*
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Local Variables:
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c-file-style: "linux"
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c-basic-offset: 4
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tab-width: 4
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End:
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*/
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