From 2618ffbe19d9d68d40f6d0b918a4673255bff60d Mon Sep 17 00:00:00 2001
From: Peter Volkov <peter.volkov@gmail.com>
Date: Sat, 25 Jul 2026 15:23:27 +0300
Subject: [PATCH] openrc: avoid converting failed PTY reads to size_t

openrc-run and rc_logger used read()'s return value as a size_t without
checking for errors. Since read() returns an ssize_t, a failure return
value -1 was converted to SIZE_MAX.

This path was normally hidden because the reader processes retained
slave_tty, preventing the master from reporting a hangup. However, read()
may still fail for other reasons, so handle its result explicitly.

With this path handled, it is also safe to close the unused slave_tty
descriptors.
---
 src/openrc-run/openrc-run.c | 22 +++++++++++++++--
 src/openrc/rc-logger.c      | 48 ++++++++++++++++++++++++-------------
 2 files changed, 51 insertions(+), 19 deletions(-)

diff --git a/src/openrc-run/openrc-run.c b/src/openrc-run/openrc-run.c
index 380d4c7f9..39a84d1a7 100644
--- a/src/openrc-run/openrc-run.c
+++ b/src/openrc-run/openrc-run.c
@@ -416,6 +416,11 @@ svc_exec(const char *command)
 		return 1;
 	}
 
+	if (slave_tty >= 0) {
+		close(slave_tty);
+		slave_tty = -1;
+	}
+
 	posix_spawn_file_actions_destroy(&tty);
 	free(openrc_sh);
 
@@ -432,9 +437,22 @@ svc_exec(const char *command)
 			break;
 		}
 
-		if (fd[1].revents & (POLLIN | POLLHUP)) {
+		if (master_tty >= 0 &&
+		    (fd[1].revents & (POLLIN | POLLHUP))) {
 			char buffer[BUFSIZ];
-			write_prefix(buffer, read(master_tty, buffer, BUFSIZ), &prefixed);
+			ssize_t bytes;
+
+			bytes = read(master_tty, buffer, BUFSIZ);
+			if (bytes > 0)
+				write_prefix(buffer, (size_t)bytes, &prefixed);
+			else if (bytes == 0 ||
+			    (bytes == -1 && errno != EINTR)) {
+				if (bytes == -1 && errno != EIO)
+					eerror("%s: read: %s", applet, strerror(errno));
+				close(master_tty);
+				master_tty = -1;
+				fd[1].fd = -1;
+			}
 		}
 
 		/* signal_pipe receives service_pid's exit status */
diff --git a/src/openrc/rc-logger.c b/src/openrc/rc-logger.c
index e57d38037..f90286c8b 100644
--- a/src/openrc/rc-logger.c
+++ b/src/openrc/rc-logger.c
@@ -155,6 +155,7 @@ rc_logger_open(const char *level)
 	struct pollfd fd[2];
 	int s = 0;
 	size_t bytes;
+	ssize_t bytes_read;
 	FILE *log = NULL;
 	FILE *plog = NULL;
 	const char *logfile;
@@ -191,6 +192,8 @@ rc_logger_open(const char *level)
 		rc_in_logger = true;
 		close(signal_pipe[1]);
 		signal_pipe[1] = -1;
+		close(slave_tty);
+		slave_tty = -1;
 
 		runlevel = level;
 		xasprintf(&tmplog, "%s/rc.log", rc_svcdir());
@@ -217,25 +220,36 @@ rc_logger_open(const char *level)
 			} else if (s == 0)
 				continue;
 
-			if (fd[1].revents & (POLLIN | POLLHUP)) {
+			if (rc_logger_tty >= 0 &&
+			    (fd[1].revents & (POLLIN | POLLHUP))) {
 				memset(buffer, 0, BUFSIZ);
-				bytes = read(rc_logger_tty, buffer, BUFSIZ);
-				if (write(STDOUT_FILENO, buffer, bytes) == -1)
-					eerror("write: %s", strerror(errno));
-
-				if (log)
-					write_log(fileno (log), buffer, bytes);
-				else {
-					if (logbuf_size - logbuf_len < bytes) {
-						logbuf_size += BUFSIZ * 10;
-						logbuf = xrealloc(logbuf,
-						    sizeof(char ) *
-						    logbuf_size);
+				bytes_read = read(rc_logger_tty, buffer, BUFSIZ);
+				if (bytes_read > 0) {
+					bytes = (size_t)bytes_read;
+					if (write(STDOUT_FILENO, buffer, bytes) == -1)
+						eerror("write: %s", strerror(errno));
+
+					if (log)
+						write_log(fileno (log), buffer, bytes);
+					else {
+						if (logbuf_size - logbuf_len < bytes) {
+							logbuf_size += BUFSIZ * 10;
+							logbuf = xrealloc(logbuf,
+							    sizeof(char ) *
+							    logbuf_size);
+						}
+
+						memcpy(logbuf + logbuf_len,
+						    buffer, bytes);
+						logbuf_len += bytes;
 					}
-
-					memcpy(logbuf + logbuf_len,
-					    buffer, bytes);
-					logbuf_len += bytes;
+				} else if (bytes_read == 0 ||
+				    (bytes_read == -1 && errno != EINTR)) {
+					if (bytes_read == -1 && errno != EIO)
+						eerror("read: %s", strerror(errno));
+					close(rc_logger_tty);
+					rc_logger_tty = -1;
+					fd[1].fd = -1;
 				}
 			}