blocking_pipe_header *
receive_blocking_resp_internal(
blocking_child * c
)
{
blocking_pipe_header * removed;
#ifdef USE_WORK_PIPE
int rc;
char scratch[32];
do {
rc = read(c->resp_read_pipe, scratch, sizeof(scratch));
} while (-1 == rc && EINTR == errno);
#endif
removed = c->responses[c->next_workresp];
if (NULL != removed) {
c->responses[c->next_workresp] = NULL;
c->next_workresp = (1 + c->next_workresp) %
c->responses_alloc;
DEBUG_ENSURE(CHILD_GONE_RESP == removed ||
BLOCKING_RESP_MAGIC == removed->magic_sig);
}
if (CHILD_GONE_RESP == removed) {
cleanup_after_child(c);
removed = NULL;
}
return removed;
}
blocking_pipe_header *
receive_blocking_resp_internal(
blocking_child * c
)
{
blocking_pipe_header hdr;
blocking_pipe_header * resp;
int rc;
long octets;
DEBUG_REQUIRE(c->resp_read_pipe != -1);
resp = NULL;
rc = read(c->resp_read_pipe, &hdr, sizeof(hdr));
if (rc < 0) {
TRACE(1, ("receive_blocking_resp_internal: pipe read %m\n"));
} else if (0 == rc) {
/* this is the normal child exited indication */
} else if (rc != sizeof(hdr)) {
TRACE(1, ("receive_blocking_resp_internal: short header read %d of %lu\n",
rc, (u_long)sizeof(hdr)));
} else if (BLOCKING_RESP_MAGIC != hdr.magic_sig) {
TRACE(1, ("receive_blocking_resp_internal: header mismatch (0x%x)\n",
hdr.magic_sig));
} else {
INSIST(sizeof(hdr) < hdr.octets &&
hdr.octets < 16 * 1024);
resp = emalloc(hdr.octets);
memcpy(resp, &hdr, sizeof(*resp));
octets = hdr.octets - sizeof(hdr);
rc = read(c->resp_read_pipe,
(char *)resp + sizeof(*resp),
octets);
if (rc < 0)
TRACE(1, ("receive_blocking_resp_internal: pipe data read %m\n"));
else if (rc < octets)
TRACE(1, ("receive_blocking_resp_internal: short read %d of %ld\n",
rc, octets));
else
return resp;
}
cleanup_after_child(c);
if (resp != NULL)
free(resp);
return NULL;
}
/* --------------------------------------------------------------------
* Fetch the next response from the return queue. In case of signalling
* via pipe, make sure the pipe is flushed, too.
*/
blocking_pipe_header *
receive_blocking_resp_internal(
blocking_child * c
)
{
blocking_pipe_header * removed;
size_t qhead, qtail, slot;
#ifdef WORK_PIPE
int rc;
char scratch[32];
do
rc = read(c->resp_read_pipe, scratch, sizeof(scratch));
while (-1 == rc && EINTR == errno);
#endif
/* >>>> ACCESS LOCKING STARTS >>>> */
wait_for_sem(c->accesslock, NULL);
qhead = c->head_response;
qtail = c->tail_response;
for (removed = NULL; !removed && (qhead != qtail); ++qtail) {
slot = qtail % c->responses_alloc;
removed = c->responses[slot];
c->responses[slot] = NULL;
}
c->tail_response = qtail;
tickle_sem(c->accesslock);
/* <<<< ACCESS LOCKING ENDS <<<< */
if (NULL != removed) {
DEBUG_ENSURE(CHILD_GONE_RESP == removed ||
BLOCKING_RESP_MAGIC == removed->magic_sig);
}
if (CHILD_GONE_RESP == removed) {
cleanup_after_child(c);
removed = NULL;
}
return removed;
}