Re: [Libguestfs] [libnbd PATCH v3 22/29] CONNECT_COMMAND.START: check syscalls for errors in the child process

It's bad hygiene to just assume dup2(), close() and signal() will succeed. Check all return values. Signed-off-by: Laszlo Ersek <lersek(a)redhat.com&gt; --- 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. */