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/* $Id: network.c,v 1.2 2003-07-31 23:38:28 rjkaes Exp $
*
* The functions found here are used for communicating across a
* network. They include both safe reading and writing (which are
* the basic building blocks) along with two functions for
* easily reading a line of text from the network, and a function
* to write an arbitrary amount of data to the network.
*
* Copyright (C) 2002 Robert James Kaes (rjkaes@flarenet.com)
*
* 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.
*/
#include "tinyproxy.h"
#include "heap.h"
#include "network.h"
/*
* Write the buffer to the socket. If an EINTR occurs, pick up and try
* again. Keep sending until the buffer has been sent.
*/
ssize_t
safe_write(int fd, const char *buffer, size_t count)
{
ssize_t len;
size_t bytestosend;
assert(fd >= 0);
assert(buffer != NULL);
assert(count > 0);
bytestosend = count;
while (1) {
len = send(fd, buffer, bytestosend, MSG_NOSIGNAL);
if (len < 0) {
if (errno == EINTR)
continue;
else
return -errno;
}
if (len == bytestosend)
break;
buffer += len;
bytestosend -= len;
}
return count;
}
/*
* Matched pair for safe_write(). If an EINTR occurs, pick up and try
* again.
*/
ssize_t
safe_read(int fd, char *buffer, size_t count)
{
ssize_t len;
do {
len = read(fd, buffer, count);
} while (len < 0 && errno == EINTR);
return len;
}
/*
* Send a "message" to the file descriptor provided. This handles the
* differences between the various implementations of vsnprintf. This code
* was basically stolen from the snprintf() man page of Debian Linux
* (although I did fix a memory leak. :)
*/
int
write_message(int fd, const char *fmt, ...)
{
ssize_t n;
size_t size = (1024 * 8); /* start with 8 KB and go from there */
char *buf, *tmpbuf;
va_list ap;
if ((buf = (char*)safemalloc(size)) == NULL)
return -1;
while (1) {
va_start(ap, fmt);
n = vsnprintf(buf, size, fmt, ap);
va_end(ap);
/* If that worked, break out so we can send the buffer */
if (n > -1 && n < size)
break;
/* Else, try again with more space */
if (n > -1)
/* precisely what is needed (glibc2.1) */
size = n + 1;
else
/* twice the old size (glibc2.0) */
size *= 2;
if ((tmpbuf = (char*)saferealloc(buf, size)) == NULL) {
safefree(buf);
return -1;
} else
buf = tmpbuf;
}
if (safe_write(fd, buf, n) < 0) {
safefree(buf);
return -1;
}
safefree(buf);
return 0;
}
/*
* Read in a "line" from the socket. It might take a few loops through
* the read sequence. The full string is allocate off the heap and stored
* at the whole_buffer pointer. The caller needs to free the memory when
* it is no longer in use. The returned line is NULL terminated.
*
* Returns the length of the buffer on success (not including the NULL
* termination), 0 if the socket was closed, and -1 on all other errors.
*/
#define SEGMENT_LEN (512)
#define MAXIMUM_BUFFER_LENGTH (128 * 1024)
ssize_t
readline(int fd, char **whole_buffer)
{
ssize_t whole_buffer_len;
char buffer[SEGMENT_LEN];
char *ptr;
ssize_t ret;
ssize_t diff;
struct read_lines_s {
char *data;
size_t len;
struct read_lines_s *next;
};
struct read_lines_s *first_line, *line_ptr;
first_line =
(struct read_lines_s*)safecalloc(sizeof(struct read_lines_s), 1);
if (!first_line)
return -ENOMEM;
line_ptr = first_line;
whole_buffer_len = 0;
for (;;) {
ret = recv(fd, buffer, SEGMENT_LEN, MSG_PEEK);
if (ret <= 0)
goto CLEANUP;
ptr = (char*)memchr(buffer, '\n', ret);
if (ptr)
diff = ptr - buffer + 1;
else
diff = ret;
whole_buffer_len += diff;
/*
* Don't allow the buffer to grow without bound. If we
* get to more than MAXIMUM_BUFFER_LENGTH close.
*/
if (whole_buffer_len > MAXIMUM_BUFFER_LENGTH) {
ret = -ERANGE;
goto CLEANUP;
}
line_ptr->data = (char*)safemalloc(diff);
if (!line_ptr->data) {
ret = -ENOMEM;
goto CLEANUP;
}
recv(fd, line_ptr->data, diff, 0);
line_ptr->len = diff;
if (ptr) {
line_ptr->next = NULL;
break;
}
line_ptr->next =
(struct read_lines_s*)safecalloc(sizeof(struct read_lines_s), 1);
if (!line_ptr->next) {
ret = -ENOMEM;
goto CLEANUP;
}
line_ptr = line_ptr->next;
}
*whole_buffer = (char*)safemalloc(whole_buffer_len + 1);
if (!*whole_buffer) {
ret = -ENOMEM;
goto CLEANUP;
}
*(*whole_buffer + whole_buffer_len) = '\0';
whole_buffer_len = 0;
line_ptr = first_line;
while (line_ptr) {
memcpy(*whole_buffer + whole_buffer_len, line_ptr->data,
line_ptr->len);
whole_buffer_len += line_ptr->len;
line_ptr = line_ptr->next;
}
ret = whole_buffer_len;
CLEANUP:
do {
line_ptr = first_line->next;
if (first_line->data)
safefree(first_line->data);
safefree(first_line);
first_line = line_ptr;
} while (first_line);
return ret;
}
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