commit ee0aac2f009a841246854bc189070f07803d0d2e
from: Omar Polo <op@omarpolo.com>
date: Wed May 25 18:03:07 2022 UTC

work around macos lack of SOCK_CLOEXEC / SOCK_NONBLOCK

rework mark_nonblock so it sets the cloexec flag too and use it in
control.c to avoid these flags.  (which are expected to become available
on a future revision of POSIX and are already widely available.)

It's not an issue for telescope to do the socket/accept + fcntl dance
because there aren't threads that can fork(2) (there are no threads at
all!)

reported by @sikmir at github

https://github.com/omar-polo/telescope/commit/59ef79dd19611c7846b00427e6f2267c748ae290#r74498414

commit - 8307a7c8a20d43ed32440d3a15197e4f5a804022
commit + ee0aac2f009a841246854bc189070f07803d0d2e
blob - 10acae1b1d3ecb0e2c6fac34c7fd1f50b483b38b
blob + b2cba8137f48f2e155021927aea8685178e2d619
--- control.c
+++ control.c
@@ -61,12 +61,16 @@ control_init(char *path)
 	int			 fd;
 	mode_t			 old_umask;
 
-	if ((fd = socket(AF_UNIX, SOCK_STREAM | SOCK_CLOEXEC | SOCK_NONBLOCK,
-	    0)) == -1) {
+	if ((fd = socket(AF_UNIX, SOCK_STREAM, 0)) == -1) {
 		warn("%s: socket", __func__);
 		return (-1);
 	}
 
+	if (!mark_nonblock_cloexec(fd)) {
+		close(fd);
+		return (-1);
+	}
+
 	memset(&sun, 0, sizeof(sun));
 	sun.sun_family = AF_UNIX;
 	strlcpy(sun.sun_path, path, sizeof(sun.sun_path));
@@ -127,8 +131,7 @@ control_accept(int listenfd, short event, void *bula)
 		return;
 
 	len = sizeof(sun);
-	if ((connfd = accept4(listenfd, (struct sockaddr *)&sun, &len,
-	    SOCK_CLOEXEC | SOCK_NONBLOCK)) == -1) {
+	if ((connfd = accept(listenfd, (struct sockaddr *)&sun, &len)) == -1) {
 		/*
 		 * Pause accept if we are out of file descriptors, or
 		 * libevent will haunt us here too.
@@ -144,6 +147,13 @@ control_accept(int listenfd, short event, void *bula)
 		return;
 	}
 
+	if (!mark_nonblock_cloexec(connfd)) {
+		message("%s: mark_nonblock_cloexec: %s", __func__,
+		    strerror(errno));
+		close(connfd);
+		return;
+	}
+
 	if ((c = calloc(1, sizeof(struct ctl_conn))) == NULL) {
 		message("%s: calloc: %s", __func__, strerror(errno));
 		close(connfd);
blob - faa6df63aa90f545848a3d44d2f14cdba3239fd0
blob + 588673966051ca334bb6556f4e9054308ee8bc64
--- include/utils.h
+++ include/utils.h
@@ -17,7 +17,7 @@
 #ifndef UTILS_H
 #define UTILS_H
 
-int		 mark_nonblock(int);
+int		 mark_nonblock_cloexec(int);
 
 int		 has_suffix(const char *, const char *);
 int		 unicode_isspace(uint32_t);
blob - 35e3674d618b8b5ad01dd54d45f883e9fde01359
blob + 48ce206255dcef21d57c0556dcd570f965041aea
--- net.c
+++ net.c
@@ -173,7 +173,7 @@ again:
 		req->p = req->p->ai_next;
 		goto again;
 	} else {
-		mark_nonblock(req->fd);
+		mark_nonblock_cloexec(req->fd);
 		if (connect(req->fd, req->p->ai_addr, req->p->ai_addrlen) == 0)
 			goto done;
 		yield_w(req, try_to_connect, NULL);
blob - d36b92c69e0f2fb8092ed347f7bc3ccab891c9c3
blob + a78de2d3db7f7b2d79d10c46adc1229c634d5ca7
--- utils.c
+++ utils.c
@@ -27,7 +27,7 @@
 #include "utils.h"
 
 int
-mark_nonblock(int fd)
+mark_nonblock_cloexec(int fd)
 {
 	int flags;
 
@@ -35,6 +35,8 @@ mark_nonblock(int fd)
 		return 0;
 	if (fcntl(fd, F_SETFL, flags | O_NONBLOCK) == -1)
 		return 0;
+	if (fcntl(fd, F_SETFD, FD_CLOEXEC) == -1)
+		return 0;
 	return 1;
 }