mirror of
git://sourceware.org/git/lvm2.git
synced 2024-12-21 13:34:40 +03:00
95 lines
2.9 KiB
C
95 lines
2.9 KiB
C
/*
|
|
* Copyright (C) 2011-2013 Red Hat, Inc.
|
|
*
|
|
* This file is part of LVM2.
|
|
*
|
|
* This copyrighted material is made available to anyone wishing to use,
|
|
* modify, copy, or redistribute it subject to the terms and conditions
|
|
* of the GNU Lesser General Public License v.2.1.
|
|
*
|
|
* You should have received a copy of the GNU Lesser General Public License
|
|
* along with this program; if not, write to the Free Software Foundation,
|
|
* Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
|
|
*/
|
|
|
|
#include "daemon-io.h"
|
|
#include "libdevmapper.h"
|
|
|
|
#include <errno.h>
|
|
#include <stdio.h>
|
|
#include <string.h>
|
|
#include <unistd.h>
|
|
|
|
/*
|
|
* Read a single message from a (socket) filedescriptor. Messages are delimited
|
|
* by blank lines. This call will block until all of a message is received. The
|
|
* memory will be allocated from heap. Upon error, all memory is freed and the
|
|
* buffer pointer is set to NULL.
|
|
*
|
|
* See also write_buffer about blocking (read_buffer has identical behaviour).
|
|
*/
|
|
int buffer_read(int fd, struct buffer *buffer) {
|
|
int result;
|
|
|
|
if (!buffer_realloc(buffer, 32)) /* ensure we have some space */
|
|
return 0;
|
|
|
|
while (1) {
|
|
result = read(fd, buffer->mem + buffer->used, buffer->allocated - buffer->used);
|
|
if (result > 0) {
|
|
buffer->used += result;
|
|
if (buffer->used >= 4 && !strncmp((buffer->mem) + buffer->used - 4, "\n##\n", 4)) {
|
|
buffer->used -= 4;
|
|
buffer->mem[buffer->used] = 0;
|
|
break; /* success, we have the full message now */
|
|
}
|
|
if ((buffer->allocated - buffer->used < 32) &&
|
|
!buffer_realloc(buffer, 1024))
|
|
return 0;
|
|
} else if (result == 0) {
|
|
errno = ECONNRESET;
|
|
return 0; /* we should never encounter EOF here */
|
|
} else if (result < 0 && ( errno == EAGAIN || errno == EWOULDBLOCK ||
|
|
errno == EINTR || errno == EIO)) {
|
|
fd_set in;
|
|
FD_ZERO(&in);
|
|
FD_SET(fd, &in);
|
|
/* ignore the result, this is just a glorified sleep */
|
|
select(FD_SETSIZE, &in, NULL, NULL, NULL);
|
|
} else if (result < 0)
|
|
return 0;
|
|
}
|
|
|
|
return 1;
|
|
}
|
|
|
|
/*
|
|
* Write a buffer to a filedescriptor. Keep trying. Blocks (even on
|
|
* SOCK_NONBLOCK) until all of the write went through.
|
|
*/
|
|
int buffer_write(int fd, const struct buffer *buffer) {
|
|
static const struct buffer _terminate = { .mem = (char *) "\n##\n", .used = 4 };
|
|
const struct buffer *use;
|
|
int done, written, result;
|
|
|
|
for (done = 0; done < 2; ++done) {
|
|
use = (done == 0) ? buffer : &_terminate;
|
|
for (written = 0; written < use->used;) {
|
|
result = write(fd, use->mem + written, use->used - written);
|
|
if (result > 0)
|
|
written += result;
|
|
else if (result < 0 && ( errno == EAGAIN || errno == EWOULDBLOCK ||
|
|
errno == EINTR || errno == EIO)) {
|
|
fd_set out;
|
|
FD_ZERO(&out);
|
|
FD_SET(fd, &out);
|
|
/* ignore the result, this is just a glorified sleep */
|
|
select(FD_SETSIZE, NULL, &out, NULL, NULL);
|
|
} else if (result < 0)
|
|
return 0; /* too bad */
|
|
}
|
|
}
|
|
|
|
return 1;
|
|
}
|