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authorTom Gundersen <teg@jklm.no>2015-04-21 18:55:05 +0200
committerTom Gundersen <teg@jklm.no>2015-04-24 20:18:49 +0200
commit979558f3227cc0242c4b7fd4a9978e2562ed473e (patch)
tree90c2394a5de747d300b9a8dd11ab6e68fe0d451e
parent0f5a8be5fe6feb56fa306a793be7230fa630b93c (diff)
udevd: worker - let the kernel attach the sender pid
No need to include this explicitly, just use SCM_CREDENTIALS.
-rw-r--r--src/udev/udevd.c52
1 files changed, 45 insertions, 7 deletions
diff --git a/src/udev/udevd.c b/src/udev/udevd.c
index a84b407ded..27caaf14a0 100644
--- a/src/udev/udevd.c
+++ b/src/udev/udevd.c
@@ -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;