/*************************************************************************\
|
* Copyright (C) Michael Kerrisk, 2019. *
|
* *
|
* This program is free software. You may use, modify, and redistribute it *
|
* under the terms of the GNU General Public License as published by the *
|
* Free Software Foundation, either version 3 or (at your option) any *
|
* later version. This program is distributed without any warranty. See *
|
* the file COPYING.gpl-v3 for details. *
|
\*************************************************************************/
|
|
/* Listing 59-5 */
|
|
/* is_seqnum.h
|
|
Header file for is_seqnum_sv.c and is_seqnum_cl.c.
|
*/
|
#include <netinet/in.h>
|
#include <sys/socket.h>
|
#include <signal.h>
|
#include "usg_common.h"
|
|
#define PORT_NUM "50000" /* Port number for server */
|
|
#define INT_LEN 30 /* Size of string able to hold largest
|
integer (including terminating '\n') */
|
|
ssize_t
|
readLine(int fd, void *buffer, size_t n)
|
{
|
ssize_t numRead; /* # of bytes fetched by last read() */
|
size_t totRead; /* Total bytes read so far */
|
char *buf;
|
char ch;
|
|
if (n <= 0 || buffer == NULL) {
|
errno = EINVAL;
|
return -1;
|
}
|
|
buf = (char *)buffer; /* No pointer arithmetic on "void *" */
|
|
totRead = 0;
|
for (;;) {
|
numRead = read(fd, &ch, 1);
|
|
if (numRead == -1) {
|
if (errno == EINTR) /* Interrupted --> restart read() */
|
continue;
|
else
|
return -1; /* Some other error */
|
|
} else if (numRead == 0) { /* EOF */
|
if (totRead == 0) /* No bytes read; return 0 */
|
return 0;
|
else /* Some bytes read; add '\0' */
|
break;
|
|
} else { /* 'numRead' must be 1 if we get here */
|
if (totRead < n - 1) { /* Discard > (n - 1) bytes */
|
totRead++;
|
*buf++ = ch;
|
}
|
|
if (ch == '\n')
|
break;
|
}
|
}
|
|
*buf = '\0';
|
return totRead;
|
}
|
