unlink() an existing file, before opening it, simply truncating can

cause nasty problems if overwriting glibc, spotted by waldi.

1 files changed, 2 insertions, 1 deletions

diff --git a/archival/tar.c b/archival/tar.c
index c39d5787f..23af9ffa3 100644
--- a/archival/tar.c
+++ b/archival/tar.c
@@ -472,7 +472,8 @@ static inline int writeTarFile(const char *tarName, const int verboseFlag,
                 tbInfo.tarFd = fileno(stdout);
                 tbInfo.verboseFlag = verboseFlag ? 2 : 0;
         } else {
-                tbInfo.tarFd = open(tarName, O_WRONLY | O_CREAT | O_TRUNC, 0644);
+                unlink(tarName);
+                tbInfo.tarFd = open(tarName, O_WRONLY | O_CREAT | O_EXCL, 0644);
                 tbInfo.verboseFlag = verboseFlag ? 1 : 0;
         }