hush/tail.c
Eric Andersen 98bbd688a8 Commit the rewrite of tail by Allen Soard
<esp-software@mail.hypermart.net>.  Thanks Allen for
you work at getting this into shape,
 -Erik
2000-07-31 17:05:58 +00:00

321 lines
6.3 KiB
C

/* vi: set sw=4 ts=4: */
/* 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>.
Compleate Rewrite to correctly support "-NUM", "+NUM", and "-s" by
E.Allen Soard (esp@espsw.net).
*/
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>
#include <getopt.h>
#include "internal.h"
#define STDIN "standard input"
#define LINES 0
#define BYTES 1
static int n_files = 0;
static char **files = NULL;
static char follow=0;
#ifdef BB_FEATURE_SIMPLE_TAIL
static const char unit_type=LINES;
static const char sleep_int=1;
#else
static char unit_type=LINES;
static int sleep_int=1;
static char verbose = 0;
#endif
//static off_t units=-11;
static off_t units=0;
int tail_stream(int file_id)
{
int fd;
ssize_t bytes_read=0;
ssize_t bs=BUFSIZ;
ssize_t startpoint=bs;
ssize_t endpoint=0;
ssize_t count=0;
ssize_t filesize=0;
ssize_t filelocation=0;
char direction=1;
char * buffer;
char pipe;
if (!strcmp(files[file_id], STDIN))
fd = 0;
else
fd = open(files[file_id], O_RDONLY);
if (fd == -1)
fatalError("Unable to open file %s.\n", files[file_id]);
buffer=malloc(bs);
filesize=lseek(fd, -1, SEEK_END)+1;
pipe=(filesize<=0);
if(units>=0)
lseek(fd,0,SEEK_SET);
else {
direction=-1;
count=1;
}
while(units != 0) {
if (pipe) {
char * line;
ssize_t f_size=0;
bs=BUFSIZ;
line=malloc(bs);
while(1) {
bytes_read=read(fd,line,bs);
if(bytes_read<=0)
break;
buffer=realloc(buffer,f_size+bytes_read);
memcpy(&buffer[f_size],line,bytes_read);
filelocation=f_size+=bytes_read;
}
bs=f_size;
if(direction<0)
bs--;
if (line)
free(line);
} else {
filelocation = lseek(fd, 0, SEEK_CUR);
if(direction<0) {
if(filelocation<bs)
bs=filelocation;
filelocation = lseek(fd, -bs, SEEK_CUR);
}
bytes_read = read(fd, buffer, bs);
if (bytes_read <= 0)
break;
bs=bytes_read;
}
startpoint=bs;
if(direction>0) {
endpoint=startpoint;
startpoint=0;
}
for(;startpoint!=endpoint;startpoint+=direction) {
#ifndef BB_FEATURE_SIMPLE_TAIL
if(unit_type==BYTES)
count++;
else
#endif
if(buffer[startpoint-1]=='\n')
count++;
if (!pipe)
filelocation=lseek(fd,0,SEEK_CUR);
if(count==abs(units))
break;
}
if((count==abs(units)) | pipe)
break;
if(direction<0){
filelocation = lseek(fd, -bytes_read, SEEK_CUR);
if(filelocation==0)
break;
}
}
if(pipe && (direction<0))
bs++;
bytes_read=bs-startpoint;
memcpy(&buffer[0],&buffer[startpoint],bytes_read);
bs=BUFSIZ;
while (1) {
if((filelocation>0 || pipe)){
write(1,buffer,bytes_read);
}
bytes_read = read(fd, buffer, bs);
filelocation+=bytes_read;
if (bytes_read <= 0) {
if (!follow) {
close(fd);
break;
}
sleep(sleep_int);
}
usleep(sleep_int * 1000);
}
if (buffer)
free(buffer);
return 0;
}
void add_file(char *name)
{
++n_files;
files = realloc(files, n_files);
files[n_files - 1] = (char *) malloc(strlen(name) + 1);
strcpy(files[n_files - 1], name);
}
int tail_main(int argc, char **argv)
{
int show_headers = 1;
int test;
int c;
int nargs=0;
char **argn=NULL;
opterr = 0;
for(c=0;c<argc;c++){
test=atoi(argv[c]);
if(test){
units=test;
if(units<0)
units=units-1;
}else{
nargs++;
argn = realloc(argn, nargs);
argn[nargs - 1] = (char *) malloc(strlen(argv[c]) + 1);
strcpy(argn[nargs - 1], argv[c]);
}
}
while (1) {
int opt_index = 0;
c = getopt_long_only(nargs, argn,
"c:fhn:s:qv", NULL, &opt_index);
if (c == -1)
break;
switch (c) {
#ifndef BB_FEATURE_SIMPLE_TAIL
case 'c':
unit_type = BYTES;
test = atoi(optarg);
if(test==0)
usage(tail_usage);
if(optarg[strlen(optarg)-1]>'9') {
switch (optarg[strlen(optarg)-1]) {
case 'b':
test *= 512;
break;
case 'k':
test *= 1024;
break;
case 'm':
test *= (1024 * 1024);
break;
default:
fprintf(stderr,"Size must be b,k, or m.");
usage(tail_usage);
}
}
if(optarg[0]=='+')
units=test+1;
else
units=-(test+1);
break;
case 'q':
show_headers = 0;
break;
case 's':
sleep_int = atoi(optarg);
if(sleep_int<1)
sleep_int=1;
break;
case 'v':
verbose = 1;
break;
#endif
case 'f':
follow = 1;
break;
case 'h':
usage(tail_usage);
break;
case 'n':
test = atoi(optarg);
if (test) {
if (optarg[0] == '+')
units = test;
else
units = -(test+1);
} else
usage(tail_usage);
break;
default:
errorMsg("\nUnknown arg: %c.\n\n",c);
usage(tail_usage);
}
}
while (optind < nargs) {
if (!strcmp(argn[optind], "-"))
add_file(STDIN);
else
add_file(argn[optind]);
optind++;
}
if(units==0)
units=-11;
if(units>0)
units--;
if (n_files == 0)
add_file(STDIN);
if (n_files == 1)
#ifndef BB_FEATURE_SIMPLE_TAIL
if (!verbose)
#endif
show_headers = 0;
for (test = 0; test < n_files; test++) {
if (show_headers)
printf("==> %s <==\n", files[test]);
tail_stream(test);
}
if(files)
free(files);
if(argn)
free(argn);
return 0;
}
/*
Local Variables:
c-file-style: "linux"
c-basic-offset: 4
tab-width: 4
End:
*/