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udevd: worker - let the kernel attach the sender pid 

No need to include this explicitly, just use SCM_CREDENTIALS.
This commit is contained in:
Tom Gundersen 2015-04-21 18:55:05 +02:00
parent 0f5a8be5fe
commit 979558f322
1 changed files with 45 additions and 7 deletions
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52
src/udev/udevd.c
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@ -124,7 +124,6 @@ struct worker {
/* passed from worker to main process */
struct worker_message {
pid_t pid;
int exitcode;
};
@ -332,7 +331,6 @@ skip:
/* send udevd the result of the event execution */
memzero(&msg, sizeof(struct worker_message));
msg.exitcode = err;
msg.pid = getpid();
send(worker_watch[WRITE_END], &msg, sizeof(struct worker_message), 0);
log_debug("seq %llu processed with %i", udev_device_get_seqnum(dev), err);
@ -599,18 +597,54 @@ static void event_queue_cleanup(struct udev *udev, enum event_state match_type)
static void worker_returned(int fd_worker) {
for (;;) {
struct worker_message msg;
struct iovec iovec = {
.iov_base = &msg,
.iov_len = sizeof(msg),
};
union {
struct cmsghdr cmsghdr;
uint8_t buf[CMSG_SPACE(sizeof(struct ucred))];
} control = {};
struct msghdr msghdr = {
.msg_iov = &iovec,
.msg_iovlen = 1,
.msg_control = &control,
.msg_controllen = sizeof(control),
};
struct cmsghdr *cmsg;
ssize_t size;
struct ucred *ucred = NULL;
struct udev_list_node *loop;
size = recv(fd_worker, &msg, sizeof(struct worker_message), MSG_DONTWAIT);
if (size != sizeof(struct worker_message))
break;
size = recvmsg(fd_worker, &msghdr, MSG_DONTWAIT);
if (size < 0) {
if (errno == EAGAIN || errno == EINTR)
return;
log_error_errno(errno, "failed to receive message: %m");
return;
} else if (size != sizeof(struct worker_message)) {
log_warning_errno(EIO, "ignoring worker message with invalid size %zi bytes", size);
return;
}
for (cmsg = CMSG_FIRSTHDR(&msghdr); cmsg; cmsg = CMSG_NXTHDR(&msghdr, cmsg)) {
if (cmsg->cmsg_level == SOL_SOCKET &&
cmsg->cmsg_type == SCM_CREDENTIALS &&
cmsg->cmsg_len == CMSG_LEN(sizeof(struct ucred)))
ucred = (struct ucred*) CMSG_DATA(cmsg);
}
if (!ucred || ucred->pid <= 0) {
log_warning_errno(EIO, "ignoring worker message without valid PID");
continue;
}
/* lookup worker who sent the signal */
udev_list_node_foreach(loop, &worker_list) {
struct worker *worker = node_to_worker(loop);
if (worker->pid != msg.pid)
if (worker->pid != ucred->pid)
continue;
/* worker returned */
@ -1132,7 +1166,7 @@ int main(int argc, char *argv[]) {
struct epoll_event ep_netlink = { .events = EPOLLIN };
struct epoll_event ep_worker = { .events = EPOLLIN };
struct udev_ctrl_connection *ctrl_conn = NULL;
int rc = 1, r;
int rc = 1, r, one = 1;
udev = udev_new();
if (udev == NULL)
@ -1327,6 +1361,10 @@ int main(int argc, char *argv[]) {
}
fd_worker = worker_watch[READ_END];
r = setsockopt(fd_worker, SOL_SOCKET, SO_PASSCRED, &one, sizeof(one));
if (r < 0)
return log_error_errno(errno, "could not enable SO_PASSCRED: %m");
ep_ctrl.data.fd = fd_ctrl;
ep_inotify.data.fd = fd_inotify;
ep_signal.data.fd = fd_signal;