qemu-patch-raspberry4/cutils.c
Christoph Hellwig 6f1953c4c1 block: use fdatasync instead of fsync if possible
If we are flushing the caches for our image files we only care about the
data (including the metadata required for accessing it) but not things
like timestamp updates.  So try to use fdatasync instead of fsync to
implement the flush operations.

Unfortunately many operating systems still do not support fdatasync,
so we add a qemu_fdatasync wrapper that uses fdatasync if available
as per the _POSIX_SYNCHRONIZED_IO feature macro or fsync otherwise.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
2009-09-11 10:19:46 -05:00

236 lines
5.6 KiB
C

/*
* Simple C functions to supplement the C library
*
* Copyright (c) 2006 Fabrice Bellard
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
#include "qemu-common.h"
#include "host-utils.h"
void pstrcpy(char *buf, int buf_size, const char *str)
{
int c;
char *q = buf;
if (buf_size <= 0)
return;
for(;;) {
c = *str++;
if (c == 0 || q >= buf + buf_size - 1)
break;
*q++ = c;
}
*q = '\0';
}
/* strcat and truncate. */
char *pstrcat(char *buf, int buf_size, const char *s)
{
int len;
len = strlen(buf);
if (len < buf_size)
pstrcpy(buf + len, buf_size - len, s);
return buf;
}
int strstart(const char *str, const char *val, const char **ptr)
{
const char *p, *q;
p = str;
q = val;
while (*q != '\0') {
if (*p != *q)
return 0;
p++;
q++;
}
if (ptr)
*ptr = p;
return 1;
}
int stristart(const char *str, const char *val, const char **ptr)
{
const char *p, *q;
p = str;
q = val;
while (*q != '\0') {
if (qemu_toupper(*p) != qemu_toupper(*q))
return 0;
p++;
q++;
}
if (ptr)
*ptr = p;
return 1;
}
/* XXX: use host strnlen if available ? */
int qemu_strnlen(const char *s, int max_len)
{
int i;
for(i = 0; i < max_len; i++) {
if (s[i] == '\0') {
break;
}
}
return i;
}
time_t mktimegm(struct tm *tm)
{
time_t t;
int y = tm->tm_year + 1900, m = tm->tm_mon + 1, d = tm->tm_mday;
if (m < 3) {
m += 12;
y--;
}
t = 86400 * (d + (153 * m - 457) / 5 + 365 * y + y / 4 - y / 100 +
y / 400 - 719469);
t += 3600 * tm->tm_hour + 60 * tm->tm_min + tm->tm_sec;
return t;
}
int qemu_fls(int i)
{
return 32 - clz32(i);
}
/*
* Make sure data goes on disk, but if possible do not bother to
* write out the inode just for timestamp updates.
*
* Unfortunately even in 2009 many operating systems do not support
* fdatasync and have to fall back to fsync.
*/
int qemu_fdatasync(int fd)
{
#ifdef _POSIX_SYNCHRONIZED_IO
return fdatasync(fd);
#else
return fsync(fd);
#endif
}
/* io vectors */
void qemu_iovec_init(QEMUIOVector *qiov, int alloc_hint)
{
qiov->iov = qemu_malloc(alloc_hint * sizeof(struct iovec));
qiov->niov = 0;
qiov->nalloc = alloc_hint;
qiov->size = 0;
}
void qemu_iovec_init_external(QEMUIOVector *qiov, struct iovec *iov, int niov)
{
int i;
qiov->iov = iov;
qiov->niov = niov;
qiov->nalloc = -1;
qiov->size = 0;
for (i = 0; i < niov; i++)
qiov->size += iov[i].iov_len;
}
void qemu_iovec_add(QEMUIOVector *qiov, void *base, size_t len)
{
assert(qiov->nalloc != -1);
if (qiov->niov == qiov->nalloc) {
qiov->nalloc = 2 * qiov->nalloc + 1;
qiov->iov = qemu_realloc(qiov->iov, qiov->nalloc * sizeof(struct iovec));
}
qiov->iov[qiov->niov].iov_base = base;
qiov->iov[qiov->niov].iov_len = len;
qiov->size += len;
++qiov->niov;
}
/*
* Copies iovecs from src to the end dst until src is completely copied or the
* total size of the copied iovec reaches size. The size of the last copied
* iovec is changed in order to fit the specified total size if it isn't a
* perfect fit already.
*/
void qemu_iovec_concat(QEMUIOVector *dst, QEMUIOVector *src, size_t size)
{
int i;
size_t done;
assert(dst->nalloc != -1);
done = 0;
for (i = 0; (i < src->niov) && (done != size); i++) {
if (done + src->iov[i].iov_len > size) {
qemu_iovec_add(dst, src->iov[i].iov_base, size - done);
break;
} else {
qemu_iovec_add(dst, src->iov[i].iov_base, src->iov[i].iov_len);
}
done += src->iov[i].iov_len;
}
}
void qemu_iovec_destroy(QEMUIOVector *qiov)
{
assert(qiov->nalloc != -1);
qemu_free(qiov->iov);
}
void qemu_iovec_reset(QEMUIOVector *qiov)
{
assert(qiov->nalloc != -1);
qiov->niov = 0;
qiov->size = 0;
}
void qemu_iovec_to_buffer(QEMUIOVector *qiov, void *buf)
{
uint8_t *p = (uint8_t *)buf;
int i;
for (i = 0; i < qiov->niov; ++i) {
memcpy(p, qiov->iov[i].iov_base, qiov->iov[i].iov_len);
p += qiov->iov[i].iov_len;
}
}
void qemu_iovec_from_buffer(QEMUIOVector *qiov, const void *buf, size_t count)
{
const uint8_t *p = (const uint8_t *)buf;
size_t copy;
int i;
for (i = 0; i < qiov->niov && count; ++i) {
copy = count;
if (copy > qiov->iov[i].iov_len)
copy = qiov->iov[i].iov_len;
memcpy(qiov->iov[i].iov_base, p, copy);
p += copy;
count -= copy;
}
}