toaruos/libc/poll/poll.c

#include <poll.h>
#include <stdio.h>
#include <errno.h>
#include <sys/fswait.h>

extern char * _argv_0;

static char * poll_print_flags(int flags) {
	static char buf[100];
	char * b = buf;
	int saw_something = 0;
#define OPT(n) do { if (flags & n) { b += sprintf(b, "%s%s", saw_something ? "|" : "", #n); saw_something = 1; } } while (0)
	OPT(POLLIN);
	OPT(POLLOUT);
	OPT(POLLRDHUP);
	OPT(POLLERR);
	OPT(POLLHUP);
	OPT(POLLNVAL);
	OPT(POLLPRI);
	return buf;
}

extern int __libc_debug;

int poll(struct pollfd *fds, nfds_t nfds, int timeout) {
	int count_pollin = 0;

	for (nfds_t i = 0; i < nfds; ++i) {
		if (fds[i].events & POLLIN) {
			count_pollin++;
		}
		fds[i].revents = 0;
	}

	for (nfds_t i = 0; i < nfds; ++i) {
		if (fds[i].events & (~POLLIN)) {
			if (fds[i].events == (POLLIN | POLLPRI)) continue;
			if (__libc_debug) {
				fprintf(stderr, "%s: poll: unsupported bit set in fds: %s\n", _argv_0, poll_print_flags(fds[i].events));
			}
			if ((fds[i].events & POLLOUT) && nfds == 1) {
				fds[i].revents |= POLLOUT;
				return 1;
			}
			//if (fds[i].events & POLLIN) continue;
			//fprintf(stderr, "%s: poll: the above error is fatal\n", _argv_0);
			//return -EINVAL;
		}
	}

	int fswait_fds[count_pollin];
	int fswait_backref[count_pollin];
	int fswait_results[count_pollin];
	int j = 0;
	for (nfds_t i = 0; i < nfds; ++i) {
		if (fds[i].events & POLLIN) {
			fswait_fds[j] = fds[i].fd;
			fswait_backref[j] = i;
			j++;
		}
	}

	int ret = fswait3(count_pollin, fswait_fds, timeout, fswait_results);

	if (ret >= 0 && ret < count_pollin) {
		int count = 0;
		for (int i = 0; i < count_pollin; ++i) {
			if (fswait_results[i]) {
				fds[fswait_backref[i]].revents = POLLIN;
				count++;
			}
		}
		return count;
	} else if (ret == count_pollin) {
		return 0;
	} else {
		return ret; /* Error */
	}
}