From e6a5e33c6b7713d446d7c29ab63b2e74ce785c86 Mon Sep 17 00:00:00 2001
From: Jason Evans <jasone@FreeBSD.org>
Date: Thu, 16 Dec 1999 22:35:40 +0000
Subject: [PATCH] Avoid an infinite loop if the last element of the iov array
 passed to writev() has an iov_len of 0.

PR:		bin/8281
---
 lib/libc_r/uthread/uthread_writev.c | 14 +++++++++++++-
 lib/libkse/thread/thr_writev.c      | 14 +++++++++++++-
 lib/libpthread/thread/thr_writev.c  | 14 +++++++++++++-
 3 files changed, 39 insertions(+), 3 deletions(-)

diff --git a/lib/libc_r/uthread/uthread_writev.c b/lib/libc_r/uthread/uthread_writev.c
index 8ca5db7d826..375f59912b6 100644
--- a/lib/libc_r/uthread/uthread_writev.c
+++ b/lib/libc_r/uthread/uthread_writev.c
@@ -136,8 +136,20 @@ writev(int fd, const struct iovec * iov, int iovcnt)
 						cnt = 0;
 					}
 				}
-			}
+			} else if (n == 0) {
+				/*
+				 * Avoid an infinite loop if the last iov_len is
+				 * 0.
+				 */
+				while (idx < iovcnt && p_iov[idx].iov_len == 0)
+					idx++;
 
+				if (idx == iovcnt) {
+					ret = num;
+					break;
+				}
+			}
+                       
 			/*
 			 * If performing a blocking write, check if the
 			 * write would have blocked or if some bytes
diff --git a/lib/libkse/thread/thr_writev.c b/lib/libkse/thread/thr_writev.c
index 8ca5db7d826..375f59912b6 100644
--- a/lib/libkse/thread/thr_writev.c
+++ b/lib/libkse/thread/thr_writev.c
@@ -136,8 +136,20 @@ writev(int fd, const struct iovec * iov, int iovcnt)
 						cnt = 0;
 					}
 				}
-			}
+			} else if (n == 0) {
+				/*
+				 * Avoid an infinite loop if the last iov_len is
+				 * 0.
+				 */
+				while (idx < iovcnt && p_iov[idx].iov_len == 0)
+					idx++;
 
+				if (idx == iovcnt) {
+					ret = num;
+					break;
+				}
+			}
+                       
 			/*
 			 * If performing a blocking write, check if the
 			 * write would have blocked or if some bytes
diff --git a/lib/libpthread/thread/thr_writev.c b/lib/libpthread/thread/thr_writev.c
index 8ca5db7d826..375f59912b6 100644
--- a/lib/libpthread/thread/thr_writev.c
+++ b/lib/libpthread/thread/thr_writev.c
@@ -136,8 +136,20 @@ writev(int fd, const struct iovec * iov, int iovcnt)
 						cnt = 0;
 					}
 				}
-			}
+			} else if (n == 0) {
+				/*
+				 * Avoid an infinite loop if the last iov_len is
+				 * 0.
+				 */
+				while (idx < iovcnt && p_iov[idx].iov_len == 0)
+					idx++;
 
+				if (idx == iovcnt) {
+					ret = num;
+					break;
+				}
+			}
+                       
 			/*
 			 * If performing a blocking write, check if the
 			 * write would have blocked or if some bytes