From 9ea51aa86edac407411376d2ed18a494368b9e31 Mon Sep 17 00:00:00 2001
From: Gunnar Beutner <gunnar@beutner.name>
Date: Mon, 9 Nov 2015 20:39:26 +0100
Subject: [PATCH] Use non-blocking open() for the command pipe

fixes #10410
---
 lib/base/utility.cpp                   | 26 ++++++++++++++++++--------
 lib/base/utility.hpp                   |  6 +++---
 lib/compat/externalcommandlistener.cpp |  8 +++-----
 3 files changed, 24 insertions(+), 16 deletions(-)

diff --git a/lib/base/utility.cpp b/lib/base/utility.cpp
index 5e2ff7d6d..1101b4cba 100644
--- a/lib/base/utility.cpp
+++ b/lib/base/utility.cpp
@@ -806,7 +806,7 @@ bool Utility::SetFileOwnership(const String& file, const String& user, const Str
 }
 
 #ifndef _WIN32
-void Utility::SetNonBlocking(int fd)
+void Utility::SetNonBlocking(int fd, bool nb)
 {
 	int flags = fcntl(fd, F_GETFL, 0);
 
@@ -816,14 +816,19 @@ void Utility::SetNonBlocking(int fd)
 		    << boost::errinfo_errno(errno));
 	}
 
-	if (fcntl(fd, F_SETFL, flags | O_NONBLOCK) < 0) {
+	if (nb)
+		flags |= O_NONBLOCK;
+	else
+		flags &= ~O_NONBLOCK;
+
+	if (fcntl(fd, F_SETFL, flags) < 0) {
 		BOOST_THROW_EXCEPTION(posix_error()
 		    << boost::errinfo_api_function("fcntl")
 		    << boost::errinfo_errno(errno));
 	}
 }
 
-void Utility::SetCloExec(int fd)
+void Utility::SetCloExec(int fd, bool cloexec)
 {
 	int flags = fcntl(fd, F_GETFD, 0);
 
@@ -833,7 +838,12 @@ void Utility::SetCloExec(int fd)
 		    << boost::errinfo_errno(errno));
 	}
 
-	if (fcntl(fd, F_SETFD, flags | FD_CLOEXEC) < 0) {
+	if (cloexec)
+		flags |= FD_CLOEXEC;
+	else
+		flags &= ~FD_CLOEXEC;
+
+	if (fcntl(fd, F_SETFD, flags) < 0) {
 		BOOST_THROW_EXCEPTION(posix_error()
 		    << boost::errinfo_api_function("fcntl")
 		    << boost::errinfo_errno(errno));
@@ -841,13 +851,13 @@ void Utility::SetCloExec(int fd)
 }
 #endif /* _WIN32 */
 
-void Utility::SetNonBlockingSocket(SOCKET s)
+void Utility::SetNonBlockingSocket(SOCKET s, bool nb)
 {
 #ifndef _WIN32
-	SetNonBlocking(s);
+	SetNonBlocking(s, nb);
 #else /* _WIN32 */
-	unsigned long lTrue = 1;
-	ioctlsocket(s, FIONBIO, &lTrue);
+	unsigned long lflag = nb;
+	ioctlsocket(s, FIONBIO, &lflag);
 #endif /* _WIN32 */
 }
 
diff --git a/lib/base/utility.hpp b/lib/base/utility.hpp
index 8f386b052..0dbfc6e60 100644
--- a/lib/base/utility.hpp
+++ b/lib/base/utility.hpp
@@ -96,11 +96,11 @@ public:
 	static String FormatErrorNumber(int code);
 
 #ifndef _WIN32
-	static void SetNonBlocking(int fd);
-	static void SetCloExec(int fd);
+	static void SetNonBlocking(int fd, bool nb = true);
+	static void SetCloExec(int fd, bool cloexec = true);
 #endif /* _WIN32 */
 
-	static void SetNonBlockingSocket(SOCKET s);
+	static void SetNonBlockingSocket(SOCKET s, bool nb = true);
 
 	static String EscapeShellCmd(const String& s);
 	static String EscapeShellArg(const String& s);
diff --git a/lib/compat/externalcommandlistener.cpp b/lib/compat/externalcommandlistener.cpp
index 8785ba524..15df2b782 100644
--- a/lib/compat/externalcommandlistener.cpp
+++ b/lib/compat/externalcommandlistener.cpp
@@ -94,11 +94,7 @@ void ExternalCommandListener::CommandPipeThread(const String& commandPath)
 	}
 
 	for (;;) {
-		int fd;
-
-		do {
-			fd = open(commandPath.CStr(), O_RDONLY);
-		} while (fd < 0 && errno == EINTR);
+		int fd = open(commandPath.CStr(), O_RDONLY | O_NONBLOCK);
 
 		if (fd < 0) {
 			Log(LogCritical, "ExternalCommandListener")
@@ -106,6 +102,8 @@ void ExternalCommandListener::CommandPipeThread(const String& commandPath)
 			return;
 		}
 
+		Utility::SetNonBlocking(fd, false);
+
 		FILE *fp = fdopen(fd, "r");
 
 		if (fp == NULL) {
-- 
2.40.0