make pipes non-blocking and read output on POLLHUP (#490)

this makes it so that script outputs are read when the script
actually finishes. one objection to reading on POLLHUP was that
the script might fill up the pipe and get stuck. we already mark
the read-end as non-blocking on our end so might as well make
the write-end non-blocking as well which avoids the script
getting blocked after (and if) it fills up the pipe.

ref: https://codeberg.org/nsxiv/nsxiv/pulls/334
Closes: https://codeberg.org/nsxiv/nsxiv/issues/377

Reviewed-on: https://codeberg.org/nsxiv/nsxiv/pulls/490
Reviewed-by: eylles <eylles@noreply.codeberg.org>

1 files changed, 8 insertions, 8 deletions

diff --git a/main.c b/main.c
index 5cd8b09..85bf8f6 100644
--- a/main.c
+++ b/main.c
@@ -334,8 +334,7 @@ static void open_title(void)
 	snprintf(fcnt, ARRLEN(fcnt), "%d", filecnt);
 	construct_argv(argv, ARRLEN(argv), wintitle.f.cmd, files[fileidx].path,
 	               fidx, fcnt, w, h, z, NULL);
-	if ((wintitle.pid = spawn(&wintitle.fd, NULL, argv)) > 0)
-		fcntl(wintitle.fd, F_SETFL, O_NONBLOCK);
+	wintitle.pid = spawn(&wintitle.fd, NULL, O_NONBLOCK, argv);
 }
 
 void close_info(void)
@@ -358,8 +357,7 @@ void open_info(void)
 	}
 	construct_argv(argv, ARRLEN(argv), cmd, files[fileidx].name, w, h,
 	               files[fileidx].path, NULL);
-	if ((info.pid = spawn(&info.fd, NULL, argv)) > 0)
-		fcntl(info.fd, F_SETFL, O_NONBLOCK);
+	info.pid = spawn(&info.fd, NULL, O_NONBLOCK, argv);
 }
 
 static void read_info(void)
@@ -649,7 +647,7 @@ static bool run_key_handler(const char *key, unsigned int mask)
 	         mask & Mod1Mask    ? "M-" : "",
 	         mask & ShiftMask   ? "S-" : "", key);
 	construct_argv(argv, ARRLEN(argv), keyhandler.f.cmd, kstr, NULL);
-	if ((pid = spawn(NULL, &writefd, argv)) < 0)
+	if ((pid = spawn(NULL, &writefd, 0x0, argv)) < 0)
 		return false;
 	if ((pfs = fdopen(writefd, "w")) == NULL) {
 		error(0, errno, "open pipe");
@@ -806,13 +804,15 @@ static void run(void)
 				pfd[FD_INFO].fd = info.fd;
 				pfd[FD_TITLE].fd = wintitle.fd;
 				pfd[FD_ARL].fd = arl.fd;
-				pfd[FD_X].events = pfd[FD_INFO].events = pfd[FD_TITLE].events = pfd[FD_ARL].events = POLLIN;
+
+				pfd[FD_X].events = pfd[FD_ARL].events = POLLIN;
+				pfd[FD_INFO].events = pfd[FD_TITLE].events = 0;
 
 				if (poll(pfd, ARRLEN(pfd), to_set ? timeout : -1) < 0)
 					continue;
-				if (pfd[FD_INFO].revents & POLLIN)
+				if (pfd[FD_INFO].revents & POLLHUP)
 					read_info();
-				if (pfd[FD_TITLE].revents & POLLIN)
+				if (pfd[FD_TITLE].revents & POLLHUP)
 					read_title();
 				if ((pfd[FD_ARL].revents & POLLIN) && arl_handle(&arl)) {
 					img.autoreload_pending = true;