static Sint64 internal_sync_io(efile_win_t *w, io_op_t operation,
SysIOVec *iov, int iovlen, OVERLAPPED *overlapped) {
Sint64 bytes_processed = 0;
for(;;) {
DWORD block_bytes_processed, last_error;
BOOL succeeded;
if(iovlen < 1) {
return bytes_processed;
}
succeeded = operation(w->handle, iov->iov_base, iov->iov_len,
&block_bytes_processed, overlapped);
last_error = GetLastError();
if(!succeeded && (last_error != ERROR_HANDLE_EOF)) {
w->common.posix_errno = windows_to_posix_errno(last_error);
return -1;
} else if(block_bytes_processed == 0) {
/* EOF */
return bytes_processed;
}
if(overlapped != NULL) {
shift_overlapped(overlapped, block_bytes_processed);
}
shift_iov(&iov, &iovlen, block_bytes_processed);
bytes_processed += block_bytes_processed;
}
}
Sint64 efile_preadv(efile_data_t *d, Sint64 offset, SysIOVec *iov, int iovlen) {
efile_unix_t *u = (efile_unix_t*)d;
Uint64 bytes_read;
Sint64 result;
#if !defined(HAVE_PREADV) && !defined(HAVE_PREAD)
/* This function is documented as leaving the file position undefined, but
* the old driver always reset it so there's probably code in the wild that
* relies on this behavior. */
off_t original_position = lseek(u->fd, 0, SEEK_CUR);
if(original_position < 0 || lseek(u->fd, offset, SEEK_SET) < 0) {
u->common.posix_errno = errno;
return -1;
}
#endif
bytes_read = 0;
do {
if(iovlen < 1) {
result = 0;
break;
}
#if defined(HAVE_PREADV)
result = preadv(u->fd, iov, MIN(IOV_MAX, iovlen), offset);
#elif defined(HAVE_PREAD)
result = pread(u->fd, iov->iov_base, iov->iov_len, offset);
#else
result = read(u->fd, iov->iov_base, iov->iov_len);
#endif
if(result > 0) {
shift_iov(&iov, &iovlen, result);
bytes_read += result;
offset += result;
}
} while(result > 0 || (result < 0 && errno == EINTR));
u->common.posix_errno = errno;
#if !defined(HAVE_PREADV) && !defined(HAVE_PREAD)
if(result >= 0) {
if(lseek(u->fd, original_position, SEEK_SET) < 0) {
u->common.posix_errno = errno;
return -1;
}
}
#endif
if(result == 0 && bytes_read > 0) {
return bytes_read;
}
return result;
}
Sint64 efile_pwritev(efile_data_t *d, Sint64 offset, SysIOVec *iov, int iovlen) {
efile_unix_t *u = (efile_unix_t*)d;
Sint64 bytes_written;
ssize_t result;
#if !defined(HAVE_PWRITEV) && !defined(HAVE_PWRITE)
off_t original_position = lseek(u->fd, 0, SEEK_CUR);
if(original_position < 0 || lseek(u->fd, offset, SEEK_SET) < 0) {
u->common.posix_errno = errno;
return -1;
}
#endif
bytes_written = 0;
do {
if(iovlen < 1) {
result = 0;
break;
}
#if defined(HAVE_PWRITEV)
result = pwritev(u->fd, iov, MIN(IOV_MAX, iovlen), offset);
#elif defined(HAVE_PWRITE)
result = pwrite(u->fd, iov->iov_base, iov->iov_len, offset);
#else
result = write(u->fd, iov->iov_base, iov->iov_len);
#endif
if(result > 0) {
shift_iov(&iov, &iovlen, result);
bytes_written += result;
offset += result;
}
} while(result > 0 || (result < 0 && errno == EINTR));
u->common.posix_errno = errno;
#if !defined(HAVE_PWRITEV) && !defined(HAVE_PWRITE)
if(result >= 0) {
if(lseek(u->fd, original_position, SEEK_SET) < 0) {
u->common.posix_errno = errno;
return -1;
}
}
#endif
if(result == 0 && bytes_written > 0) {
return bytes_written;
}
return result;
}
Sint64 efile_readv(efile_data_t *d, SysIOVec *iov, int iovlen) {
efile_unix_t *u = (efile_unix_t*)d;
Sint64 bytes_read;
ssize_t result;
bytes_read = 0;
do {
int use_fallback = 0;
if(iovlen < 1) {
result = 0;
break;
}
/* writev(2) implies readv(2) */
#ifdef HAVE_WRITEV
result = readv(u->fd, iov, MIN(IOV_MAX, iovlen));
/* Fall back to using read(2) if readv(2) reports that the combined
* size of iov is greater than SSIZE_T_MAX. */
use_fallback = (result < 0 && errno == EINVAL);
#else
use_fallback = 1;
#endif
if(use_fallback) {
result = read(u->fd, iov->iov_base, iov->iov_len);
}
if(result > 0) {
shift_iov(&iov, &iovlen, result);
bytes_read += result;
}
} while(result > 0 || (result < 0 && errno == EINTR));
u->common.posix_errno = errno;
if(result == 0 && bytes_read > 0) {
return bytes_read;
}
return result;
}
