minix/lib/libasyn/asyn_wait.c
Ben Gras 2fe8fb192f Full switch to clang/ELF. Drop ack. Simplify.
There is important information about booting non-ack images in
docs/UPDATING. ack/aout-format images can't be built any more, and
booting clang/ELF-format ones is a little different. Updating to the
new boot monitor is recommended.

Changes in this commit:

	. drop boot monitor -> allowing dropping ack support
	. facility to copy ELF boot files to /boot so that old boot monitor
	  can still boot fairly easily, see UPDATING
	. no more ack-format libraries -> single-case libraries
	. some cleanup of OBJECT_FMT, COMPILER_TYPE, etc cases
	. drop several ack toolchain commands, but not all support
	  commands (e.g. aal is gone but acksize is not yet).
	. a few libc files moved to netbsd libc dir
	. new /bin/date as minix date used code in libc/
	. test compile fix
	. harmonize includes
	. /usr/lib is no longer special: without ack, /usr/lib plays no
	  kind of special bootstrapping role any more and bootstrapping
	  is done exclusively through packages, so releases depend even
	  less on the state of the machine making them now.
	. rename nbsd_lib* to lib*
	. reduce mtree
2012-02-14 14:52:02 +01:00

119 lines
2.6 KiB
C

/* asyn_wait() - wait for asynch operations Author: Kees J. Bot
* 7 Jul 1997
*/
#define DEBUG 0
#include "asyn.h"
#include <time.h>
#if DEBUG
#include <stdio.h>
#endif
#define TBOUND_MIN 1
#define TBOUND_MAX 16
int asyn_wait(asynchio_t *asyn, int flags, struct timeval *to)
/* Wait for one or more nonblocking operations to return a result. */
{
int r;
static struct timeval zero_time;
struct timeval t;
static time_t tbound= TBOUND_MIN;
/* Are there more things to do before we can block? */
if (asyn->asyn_more > 0) { asyn->asyn_more= 0; return 0; }
if (flags & ASYN_NONBLOCK) {
/* Don't block by using a zero second timeout. */
to= &zero_time;
} else
if (to != nil) {
/* asyn_wait() uses an absolute time. */
if (to->tv_usec >= 1000000L) {
to->tv_sec+= to->tv_usec / 1000000L;
to->tv_usec%= 1000000L;
}
(void) gettimeofday(&t, nil);
if (t.tv_sec > to->tv_sec || (t.tv_sec == to->tv_sec
&& t.tv_usec >= to->tv_usec)) {
to= &zero_time;
} else {
t.tv_sec= to->tv_sec - t.tv_sec;
t.tv_usec= to->tv_usec - t.tv_usec;
if (t.tv_usec < 0) {
t.tv_sec--;
t.tv_usec+= 1000000L;
}
to= &t;
}
/* Don't sleep too long, we don't trust select(). */
if (to->tv_sec > tbound) goto bound;
} else {
bound:
/* No timeout? Don't hang in (buggy?) select() forever. */
to= &t;
t.tv_sec= tbound;
t.tv_usec= 0;
}
#if DEBUG
{
int op;
fprintf(stderr, "select: ");
for (op= 0; op < SEL_NR; op++) {
fd_set *fdsetp= &asyn->asyn_fdset[op];
int fd;
for (fd= 0; fd < FD_SETSIZE; fd++) {
if (FD_ISSET(fd, fdsetp)) {
asyn->asyn_afd[fd].afd_state[op]=
PENDING;
fprintf(stderr, "%d%c", fd, "rwx"[op]);
}
}
}
fflush(stderr);
}
#endif
r= select(FD_SETSIZE, &asyn->asyn_fdset[SEL_READ],
&asyn->asyn_fdset[SEL_WRITE],
&asyn->asyn_fdset[SEL_EXCEPT], to);
#if DEBUG
fprintf(stderr, " (%d) ", r);
#endif
if (r > 0) {
/* An event occurred on one or more file descriptors. */
int op;
for (op= 0; op < SEL_NR; op++) {
fd_set *fdsetp= &asyn->asyn_fdset[op];
int fd;
for (fd= 0; fd < FD_SETSIZE; fd++) {
if (FD_ISSET(fd, fdsetp)) {
asyn->asyn_afd[fd].afd_state[op]=
PENDING;
#if DEBUG
fprintf(stderr, "%d%c", fd, "rwx"[op]);
#endif
}
}
}
tbound= TBOUND_MIN;
} else
if (r == 0) {
/* If nothing happened then let the time boundary slip a bit. */
if (tbound < TBOUND_MAX) tbound <<= 1;
}
#if DEBUG
fputc('\n', stderr);
#endif
FD_ZERO(&asyn->asyn_fdset[SEL_READ]);
FD_ZERO(&asyn->asyn_fdset[SEL_WRITE]);
FD_ZERO(&asyn->asyn_fdset[SEL_EXCEPT]);
return r == 0 ? (errno= EINTR, -1) : r;
}