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/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
#include "prio.h"
#include "prprf.h"
#include "prinit.h"
#include "prthread.h"
#include "prinrval.h"
#include "plerror.h"
#include "plgetopt.h"
#include <stdlib.h>
#define BUFFER_SIZE 500
static PRFileDesc *out = NULL, *err = NULL;
static void Help(void)
{
PR_fprintf(err, "Usage: tail [-n <n>] [-f] [-h] <filename>\n");
PR_fprintf(err, "\t-t <n> Dally time in milliseconds\n");
PR_fprintf(err, "\t-n <n> Number of bytes before <eof>\n");
PR_fprintf(err, "\t-f Follow the <eof>\n");
PR_fprintf(err, "\t-h This message and nothing else\n");
} /* Help */
PRIntn main(PRIntn argc, char **argv)
{
PRIntn rv = 0;
PLOptStatus os;
PRStatus status;
PRFileDesc *file;
PRFileInfo fileInfo;
PRIntervalTime dally;
char buffer[BUFFER_SIZE];
PRBool follow = PR_FALSE;
const char *filename = NULL;
PRUint32 position = 0, seek = 0, time = 0;
PLOptState *opt = PL_CreateOptState(argc, argv, "hfn:");
out = PR_GetSpecialFD(PR_StandardOutput);
err = PR_GetSpecialFD(PR_StandardError);
while (PL_OPT_EOL != (os = PL_GetNextOpt(opt)))
{
if (PL_OPT_BAD == os) {
continue;
}
switch (opt->option)
{
case 0: /* it's the filename */
filename = opt->value;
break;
case 'n': /* bytes before end of file */
seek = atoi(opt->value);
break;
case 't': /* dally time */
time = atoi(opt->value);
break;
case 'f': /* follow the end of file */
follow = PR_TRUE;
break;
case 'h': /* user wants some guidance */
Help(); /* so give him an earful */
return 2; /* but not a lot else */
break;
default:
break;
}
}
PL_DestroyOptState(opt);
if (0 == time) {
time = 1000;
}
dally = PR_MillisecondsToInterval(time);
if (NULL == filename)
{
(void)PR_fprintf(out, "Input file not specified\n");
rv = 1; goto done;
}
file = PR_Open(filename, PR_RDONLY, 0);
if (NULL == file)
{
PL_FPrintError(err, "File cannot be opened for reading");
return 1;
}
status = PR_GetOpenFileInfo(file, &fileInfo);
if (PR_FAILURE == status)
{
PL_FPrintError(err, "Cannot acquire status of file");
rv = 1; goto done;
}
if (seek > 0)
{
if (seek > fileInfo.size) {
seek = 0;
}
position = PR_Seek(file, (fileInfo.size - seek), PR_SEEK_SET);
if (-1 == (PRInt32)position) {
PL_FPrintError(err, "Cannot seek to starting position");
}
}
do
{
while (position < fileInfo.size)
{
PRInt32 read, bytes = fileInfo.size - position;
if (bytes > sizeof(buffer)) {
bytes = sizeof(buffer);
}
read = PR_Read(file, buffer, bytes);
if (read != bytes) {
PL_FPrintError(err, "Cannot read to eof");
}
position += read;
PR_Write(out, buffer, read);
}
if (follow)
{
PR_Sleep(dally);
status = PR_GetOpenFileInfo(file, &fileInfo);
if (PR_FAILURE == status)
{
PL_FPrintError(err, "Cannot acquire status of file");
rv = 1; goto done;
}
}
} while (follow);
done:
PR_Close(file);
return rv;
} /* main */
/* tail.c */
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