From 3281047cfca0f3848d0613e3c0d19d41b0531564 Mon Sep 17 00:00:00 2001 From: Rich Felker Date: Tue, 28 Feb 2023 15:44:46 -0500 Subject: dup3: don't set FD_CLOEXEC on failure on kernels without dup3 syscall this is the best-effort fallback path for kernels that can't actually support the dup3 functionality. it was setting FD_CLOEXEC flag on the target fd (new) even if the dup2 operation failed. normally that shouldn't happen under correct usage, but it's possible if the source fd is not open or intentionally invalid (e.g. -1). --- src/unistd/dup3.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/src/unistd/dup3.c b/src/unistd/dup3.c index 1e7dc3e7..40798bde 100644 --- a/src/unistd/dup3.c +++ b/src/unistd/dup3.c @@ -15,7 +15,8 @@ int __dup3(int old, int new, int flags) if (flags & ~O_CLOEXEC) return __syscall_ret(-EINVAL); } while ((r=__syscall(SYS_dup2, old, new))==-EBUSY); - if (flags & O_CLOEXEC) __syscall(SYS_fcntl, new, F_SETFD, FD_CLOEXEC); + if (r >= 0 && (flags & O_CLOEXEC)) + __syscall(SYS_fcntl, new, F_SETFD, FD_CLOEXEC); #else while ((r=__syscall(SYS_dup3, old, new, flags))==-EBUSY); #endif -- cgit v1.2.1