ELF: Only unlink regular files
Summary:
If the output file is a character file (e.g. /dev/null) unlinking it could
potentially destabilize the user's system. For example,
unlinking causes `lld %input -o /dev/null` to replace /dev/null with a
regular file, which will lead to unexpected behavior in other programs
that read from /dev/null, and worse than expected peformance for
programs that write to /dev/null.
This makes it possible to run the test-release.sh script as root.
Prior to this patch, the ELF/basic.s test would replace
/dev/null with a regular file, which would cause crashes in llvm
test-suite programs that piped /dev/null to stdin.
For example, if you run the test-relase.sh script as root,
Reviewers: ruiu
Reviewed By: ruiu
Subscribers: emaste, llvm-commits
Differential Revision: https://reviews.llvm.org/D34917
llvm-svn: 307092
diff --git a/lld/ELF/Filesystem.cpp b/lld/ELF/Filesystem.cpp
index b63d521..d468ae0 100644
--- a/lld/ELF/Filesystem.cpp
+++ b/lld/ELF/Filesystem.cpp
@@ -38,7 +38,8 @@
// This function spawns a background thread to call unlink.
// The calling thread returns almost immediately.
void elf::unlinkAsync(StringRef Path) {
- if (!Config->Threads || !sys::fs::exists(Config->OutputFile))
+ if (!Config->Threads || !sys::fs::exists(Config->OutputFile) ||
+ !sys::fs::is_regular_file(Config->OutputFile))
return;
// First, rename Path to avoid race condition. We cannot remove