On Wed, Feb 15, 2023 at 03:11:51PM +0100, Laszlo Ersek wrote:
> It's bad hygiene to just assume dup2(), close() and signal() will succeed.
> Check all return values.
>
> Signed-off-by: Laszlo Ersek <ler...@redhat.com>
> ---
>
> Notes:
> context:-U10
>
> generator/states-connect.c | 22 +++++++++++++++-----
> 1 file changed, 17 insertions(+), 5 deletions(-)
>
> diff --git a/generator/states-connect.c b/generator/states-connect.c
> index e08608336fd6..d2476dc11c60 100644
> --- a/generator/states-connect.c
> +++ b/generator/states-connect.c
> @@ -262,29 +262,41 @@ CONNECT_COMMAND.START:
>
> pid = fork ();
> if (pid == -1) {
> SET_NEXT_STATE (%.DEAD);
> set_error (errno, "fork");
> close (sv[0]);
> close (sv[1]);
> return 0;
> }
> if (pid == 0) { /* child - run command */
> - close (sv[0]);
> - dup2 (sv[1], STDIN_FILENO);
> - dup2 (sv[1], STDOUT_FILENO);
> + if (close (sv[0]) == -1) {
> + nbd_internal_fork_safe_perror ("close");
> + _exit (126);
> + }
> + if (dup2 (sv[1], STDIN_FILENO) == -1 ||
> + dup2 (sv[1], STDOUT_FILENO) == -1) {
> + nbd_internal_fork_safe_perror ("dup2");
> + _exit (126);
> + }
> NBD_INTERNAL_FORK_SAFE_ASSERT (sv[1] != STDIN_FILENO);
> NBD_INTERNAL_FORK_SAFE_ASSERT (sv[1] != STDOUT_FILENO);
> - close (sv[1]);
> + if (close (sv[1]) == -1) {
> + nbd_internal_fork_safe_perror ("close");
> + _exit (126);
> + }
>
> /* Restore SIGPIPE back to SIG_DFL. */
> - signal (SIGPIPE, SIG_DFL);
> + if (signal (SIGPIPE, SIG_DFL) == SIG_ERR) {
> + nbd_internal_fork_safe_perror ("signal");
> + _exit (126);
> + }
>
> execvp (h->argv.ptr[0], h->argv.ptr);
> nbd_internal_fork_safe_perror (h->argv.ptr[0]);
> if (errno == ENOENT)
> _exit (127);
> else
> _exit (126);
> }
>
> /* Parent. */
For use of exit code 126, see:
https://listman.redhat.com/archives/libguestfs/2019-September/022737.html
https://listman.redhat.com/archives/libguestfs/2019-September/022739.html
https://www.gnu.org/software/bash/manual/html_node/Exit-Status.html
Reviewed-by: Richard W.M. Jones <rjo...@redhat.com>
Rich.
--
Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones
Read my programming and virtualization blog: http://rwmj.wordpress.com
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