From dfc689efc9a5746b0c31147562c5051c45874002 Mon Sep 17 00:00:00 2001 From: Giuseppe Scrivano Date: Tue, 23 Oct 2018 22:06:14 +0200 Subject: create: fix writing cidfile when using rootless prevent opening the same file twice, since we re-exec podman in rootless mode. While at it, also solve a possible race between the check for the file and writing to it. Another process could have created the file in the meanwhile and we would just end up overwriting it. Signed-off-by: Giuseppe Scrivano --- libpod/util.go | 15 ++++----------- 1 file changed, 4 insertions(+), 11 deletions(-) (limited to 'libpod') diff --git a/libpod/util.go b/libpod/util.go index 3b51e4fcc..7007b29cd 100644 --- a/libpod/util.go +++ b/libpod/util.go @@ -24,22 +24,15 @@ const ( DefaultTransport = "docker://" ) -// WriteFile writes a provided string to a provided path -func WriteFile(content string, path string) error { +// OpenExclusiveFile opens a file for writing and ensure it doesn't already exist +func OpenExclusiveFile(path string) (*os.File, error) { baseDir := filepath.Dir(path) if baseDir != "" { if _, err := os.Stat(baseDir); err != nil { - return err + return nil, err } } - f, err := os.Create(path) - if err != nil { - return err - } - defer f.Close() - f.WriteString(content) - f.Sync() - return nil + return os.OpenFile(path, os.O_RDWR|os.O_CREATE|os.O_EXCL, 0666) } // FuncTimer helps measure the execution time of a function -- cgit v1.2.3-54-g00ecf