9b859c9ac5
read_all/write_all calls set_* on every call, so this can be noticeable performance improvement.
117 lines
2.5 KiB
C
117 lines
2.5 KiB
C
/*
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* The Qubes OS Project, http://www.qubes-os.org
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*
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* Copyright (C) 2010 Rafal Wojtczuk <rafal@invisiblethingslab.com>
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version 2
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* of the License, or (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
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*
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*/
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#include <unistd.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <fcntl.h>
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#include <errno.h>
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void perror_wrapper(char * msg)
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{
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int prev=errno;
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perror(msg);
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errno=prev;
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}
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void set_nonblock(int fd)
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{
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int fl = fcntl(fd, F_GETFL, 0);
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if (fl & O_NONBLOCK)
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return;
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fcntl(fd, F_SETFL, fl | O_NONBLOCK);
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}
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void set_block(int fd)
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{
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int fl = fcntl(fd, F_GETFL, 0);
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if (!(fl & O_NONBLOCK))
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return;
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fcntl(fd, F_SETFL, fl & ~O_NONBLOCK);
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}
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int write_all(int fd, void *buf, int size)
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{
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int written = 0;
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int ret;
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while (written < size) {
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ret = write(fd, (char *) buf + written, size - written);
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if (ret == -1 && errno == EINTR)
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continue;
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if (ret <= 0) {
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return 0;
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}
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written += ret;
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}
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// fprintf(stderr, "sent %d bytes\n", size);
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return 1;
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}
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int read_all(int fd, void *buf, int size)
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{
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int got_read = 0;
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int ret;
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while (got_read < size) {
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ret = read(fd, (char *) buf + got_read, size - got_read);
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if (ret == -1 && errno == EINTR)
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continue;
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if (ret == 0) {
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errno = 0;
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fprintf(stderr, "EOF\n");
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return 0;
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}
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if (ret < 0) {
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if (errno != EAGAIN)
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perror_wrapper("read");
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return 0;
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}
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if (got_read == 0) {
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// force blocking operation on further reads
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set_block(fd);
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}
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got_read += ret;
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}
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// fprintf(stderr, "read %d bytes\n", size);
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return 1;
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}
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int copy_fd_all(int fdout, int fdin)
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{
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int ret;
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char buf[4096];
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for (;;) {
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ret = read(fdin, buf, sizeof(buf));
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if (ret == -1 && errno == EINTR)
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continue;
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if (!ret)
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break;
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if (ret < 0) {
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perror_wrapper("read");
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return 0;
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}
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if (!write_all(fdout, buf, ret)) {
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perror_wrapper("write");
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return 0;
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}
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}
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return 1;
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}
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