qubes-linux-utils/qrexec-lib/ioall.c

113 lines
2.4 KiB
C

/*
* The Qubes OS Project, http://www.qubes-os.org
*
* Copyright (C) 2010 Rafal Wojtczuk <rafal@invisiblethingslab.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
* of the License, 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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
*
*/
#include <unistd.h>
#include <stdio.h>
#include <stdlib.h>
#include <fcntl.h>
#include <errno.h>
void perror_wrapper(char * msg)
{
int prev=errno;
perror(msg);
errno=prev;
}
void set_nonblock(int fd)
{
int fl = fcntl(fd, F_GETFL, 0);
fcntl(fd, F_SETFL, fl | O_NONBLOCK);
}
void set_block(int fd)
{
int fl = fcntl(fd, F_GETFL, 0);
fcntl(fd, F_SETFL, fl & ~O_NONBLOCK);
}
int write_all(int fd, void *buf, int size)
{
int written = 0;
int ret;
while (written < size) {
ret = write(fd, (char *) buf + written, size - written);
if (ret == -1 && errno == EINTR)
continue;
if (ret <= 0) {
return 0;
}
written += ret;
}
// fprintf(stderr, "sent %d bytes\n", size);
return 1;
}
int read_all(int fd, void *buf, int size)
{
int got_read = 0;
int ret;
while (got_read < size) {
ret = read(fd, (char *) buf + got_read, size - got_read);
if (ret == -1 && errno == EINTR)
continue;
if (ret == 0) {
errno = 0;
fprintf(stderr, "EOF\n");
return 0;
}
if (ret < 0) {
if (errno != EAGAIN)
perror_wrapper("read");
return 0;
}
if (got_read == 0) {
// force blocking operation on further reads
set_block(fd);
}
got_read += ret;
}
// fprintf(stderr, "read %d bytes\n", size);
return 1;
}
int copy_fd_all(int fdout, int fdin)
{
int ret;
char buf[4096];
for (;;) {
ret = read(fdin, buf, sizeof(buf));
if (ret == -1 && errno == EINTR)
continue;
if (!ret)
break;
if (ret < 0) {
perror_wrapper("read");
return 0;
}
if (!write_all(fdout, buf, ret)) {
perror_wrapper("write");
return 0;
}
}
return 1;
}