1 files changed, 31 insertions, 2 deletions
diff --git a/wrapper.c b/wrapper.c
index c95e2906b8..29a45d2654 100644
--- a/wrapper.c
+++ b/wrapper.c
@@ -236,8 +236,24 @@ ssize_t xread(int fd, void *buf, size_t len)
 	    len = MAX_IO_SIZE;
 	while (1) {
 		nr = read(fd, buf, len);
-		if ((nr < 0) && (errno == EAGAIN || errno == EINTR))
-			continue;
+		if (nr < 0) {
+			if (errno == EINTR)
+				continue;
+			if (errno == EAGAIN || errno == EWOULDBLOCK) {
+				struct pollfd pfd;
+				pfd.events = POLLIN;
+				pfd.fd = fd;
+				/*
+				 * it is OK if this poll() failed; we
+				 * want to leave this infinite loop
+				 * only when read() returns with
+				 * success, or an expected failure,
+				 * which would be checked by the next
+				 * call to read(2).
+				 */
+				poll(&pfd, 1, -1);
+			}
+		}
 		return nr;
 	}
 }
@@ -375,6 +391,19 @@ FILE *xfdopen(int fd, const char *mode)
 	return stream;
 }
 
+FILE *fopen_for_writing(const char *path)
+{
+	FILE *ret = fopen(path, "w");
+
+	if (!ret && errno == EPERM) {
+		if (!unlink(path))
+			ret = fopen(path, "w");
+		else
+			errno = EPERM;
+	}
+	return ret;
+}
+
 int xmkstemp(char *template)
 {
 	int fd;