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#include "postgres.h"
#include "poll_compat.h"
#ifdef PLPROXY_POLL_COMPAT
/*
* Emulate poll() with select()
*/
#include <sys/time.h>
#ifdef HAVE_SYS_SELECT_H
#include <sys/select.h>
#endif
/*
* dynamic buffer for fd_set to avoid depending on FD_SETSIZE
*/
struct fd_buf {
fd_set *set;
int alloc_bytes;
};
static void fdbuf_zero(struct fd_buf *buf)
{
if (buf->set)
memset(buf->set, 0, buf->alloc_bytes);
}
static bool fdbuf_resize(struct fd_buf *buf, int fd)
{
int need_bytes;
unsigned char *ptr;
/* default allocation */
int alloc = sizeof(fd_set);
#ifdef WIN32
int cnt = buf->set ? buf->set->fd_count : 0;
/* win32 fd_set is array of handles, +8 for count&padding */
need_bytes = (cnt + 1) * sizeof(buf->set->fd_array[0]) + 8;
#else
/* otherwise, fd_set is bitmap, +8 for int/long alignment */
need_bytes = fd / 8 + 8;
#endif
if (buf->alloc_bytes < need_bytes)
{
while (alloc < need_bytes)
alloc *= 2;
if (!buf->set)
ptr = malloc(alloc);
else
ptr = realloc(buf->set, alloc);
if (!ptr)
return false;
/* clean new area */
memset(ptr + buf->alloc_bytes, 0, alloc - buf->alloc_bytes);
buf->set = (fd_set *)ptr;
buf->alloc_bytes = alloc;
}
return true;
}
/* win32: make macros ignore FD_SETSIZE */
#undef FD_SETSIZE
#define FD_SETSIZE (1 << 30)
int poll(struct pollfd *fds, nfds_t nfds, int timeout_ms)
{
static struct fd_buf readfds = { NULL, 0 };
static struct fd_buf writefds = { NULL, 0 };
struct pollfd *pf;
int res, fd_max = 0;
struct timeval *tv = NULL;
struct timeval tvreal;
unsigned i;
/* convert timeout_ms to timeval */
if (timeout_ms >= 0)
{
tvreal.tv_sec = timeout_ms / 1000;
tvreal.tv_usec = (timeout_ms % 1000) * 1000;
tv = &tvreal;
} else if (timeout_ms < -1)
goto err_inval;
/*
* Convert pollfds to fd sets.
*/
fdbuf_zero(&readfds);
fdbuf_zero(&writefds);
for (i = 0; i < nfds; i++)
{
pf = fds + i;
if (pf->fd < 0)
goto err_badf;
/* sets must be equal size */
if (!fdbuf_resize(&readfds, pf->fd))
goto err_nomem;
if (!fdbuf_resize(&writefds, pf->fd))
goto err_nomem;
if (pf->events & POLLIN)
FD_SET((unsigned)pf->fd, readfds.set);
if (pf->events & POLLOUT)
FD_SET((unsigned)pf->fd, writefds.set);
if (pf->fd > fd_max)
fd_max = pf->fd;
}
res = select(fd_max + 1, readfds.set, writefds.set, NULL, tv);
if (res <= 0)
return res;
/*
* select() and poll() count fd-s differently,
* need to recount them here.
*/
res = 0;
for (i = 0; i < nfds; i++)
{
pf = fds + i;
pf->revents = 0;
if ((pf->events & POLLIN) && FD_ISSET(pf->fd, readfds.set))
pf->revents |= POLLIN;
if ((pf->events & POLLOUT) && FD_ISSET(pf->fd, writefds.set))
pf->revents |= POLLOUT;
if (pf->revents)
res += 1;
}
return res;
err_nomem:
errno = ENOMEM;
return -1;
err_badf:
errno = EBADF;
return -1;
err_inval:
errno = EINVAL;
return -1;
}
#endif /* PLPROXY_POLL_COMPAT */
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