[Libguestfs] [libnbd PATCH v3 04/19] socket activation: check syscalls for errors in the child process
It's bad hygiene to just assume dup2(), close() and signal() will succeed,
especially considering the inconsistency that we do check fcntl(). Check
all return values.
Signed-off-by: Laszlo Ersek <lersek(a)redhat.com>
Reviewed-by: Richard W.M. Jones <rjones(a)redhat.com>
---
Notes:
v4:
- pick up Rich's R-b
context:-U12
generator/states-connect-socket-activation.c | 15 ++++++++++++---
1 file changed, 12 insertions(+), 3 deletions(-)
diff --git a/generator/states-connect-socket-activation.c
b/generator/states-connect-socket-activation.c
index b9845c11a221..e3f7d05670b0 100644
--- a/generator/states-connect-socket-activation.c
+++ b/generator/states-connect-socket-activation.c
@@ -162,50 +162,59 @@ CONNECT_SA.START:
}
pid = fork ();
if (pid == -1) {
SET_NEXT_STATE (%.DEAD);
set_error (errno, "fork");
close (s);
string_vector_empty (&env);
return 0;
}
if (pid == 0) { /* child - run command */
if (s != FIRST_SOCKET_ACTIVATION_FD) {
- dup2 (s, FIRST_SOCKET_ACTIVATION_FD);
- close (s);
+ if (dup2 (s, FIRST_SOCKET_ACTIVATION_FD) == -1) {
+ nbd_internal_fork_safe_perror ("dup2");
+ _exit (126);
+ }
+ if (close (s) == -1) {
+ nbd_internal_fork_safe_perror ("close");
+ _exit (126);
+ }
}
else {
/* We must unset CLOEXEC on the fd. (dup2 above does this
* implicitly because CLOEXEC is set on the fd, not on the
* socket).
*/
int flags = fcntl (s, F_GETFD, 0);
if (flags == -1) {
nbd_internal_fork_safe_perror ("fcntl: F_GETFD");
_exit (126);
}
if (fcntl (s, F_SETFD, (int)(flags & ~(unsigned)FD_CLOEXEC)) == -1) {
nbd_internal_fork_safe_perror ("fcntl: F_SETFD");
_exit (126);
}
}
char buf[32];
const char *v =
nbd_internal_fork_safe_itoa ((long) getpid (), buf, sizeof buf);
strcpy (&env.ptr[0][PREFIX_LENGTH], v);
/* 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);
+ }
environ = env.ptr;
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. */
close (s);