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homed: port to notify_recv_with_fds()

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Found another implementation of the sd_notify() reception. Modernize it.
This commit is contained in:
Lennart Poettering 2025-02-28 09:24:52 +01:00
parent 19ade24464
commit a147e72add
1 changed files with 19 additions and 104 deletions
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123
src/home/homed-manager.c
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@ -37,6 +37,7 @@
#include "homed-varlink.h"
#include "io-util.h"
#include "mkdir.h"
#include "notify-recv.h"
#include "openssl-util.h"
#include "process-util.h"
#include "quota-util.h"
@ -1068,123 +1069,33 @@ static int manager_bind_varlink(Manager *m) {
return 0;
}
static ssize_t read_datagram(
int fd,
struct ucred *ret_sender,
void **ret,
int *ret_passed_fd) {
CMSG_BUFFER_TYPE(CMSG_SPACE(sizeof(struct ucred)) + CMSG_SPACE(sizeof(int))) control;
_cleanup_free_ void *buffer = NULL;
_cleanup_close_ int passed_fd = -EBADF;
struct ucred *sender = NULL;
struct cmsghdr *cmsg;
struct msghdr mh;
struct iovec iov;
ssize_t n, m;
assert(fd >= 0);
assert(ret_sender);
assert(ret);
assert(ret_passed_fd);
n = next_datagram_size_fd(fd);
if (n < 0)
return n;
buffer = malloc(n + 2);
if (!buffer)
return -ENOMEM;
/* Pass one extra byte, as a size check */
iov = IOVEC_MAKE(buffer, n + 1);
mh = (struct msghdr) {
.msg_iov = &iov,
.msg_iovlen = 1,
.msg_control = &control,
.msg_controllen = sizeof(control),
};
m = recvmsg_safe(fd, &mh, MSG_DONTWAIT|MSG_CMSG_CLOEXEC);
if (m < 0)
return m;
/* Ensure the size matches what we determined before */
if (m != n) {
cmsg_close_all(&mh);
return -EMSGSIZE;
}
CMSG_FOREACH(cmsg, &mh) {
if (cmsg->cmsg_level == SOL_SOCKET &&
cmsg->cmsg_type == SCM_CREDENTIALS &&
cmsg->cmsg_len == CMSG_LEN(sizeof(struct ucred))) {
assert(!sender);
sender = CMSG_TYPED_DATA(cmsg, struct ucred);
}
if (cmsg->cmsg_level == SOL_SOCKET &&
cmsg->cmsg_type == SCM_RIGHTS) {
if (cmsg->cmsg_len != CMSG_LEN(sizeof(int))) {
cmsg_close_all(&mh);
return -EMSGSIZE;
}
assert(passed_fd < 0);
passed_fd = *CMSG_TYPED_DATA(cmsg, int);
}
}
if (sender)
*ret_sender = *sender;
else
*ret_sender = (struct ucred) UCRED_INVALID;
*ret_passed_fd = TAKE_FD(passed_fd);
/* For safety reasons: let's always NUL terminate. */
((char*) buffer)[n] = 0;
*ret = TAKE_PTR(buffer);
return 0;
}
static int on_notify_socket(sd_event_source *s, int fd, uint32_t revents, void *userdata) {
_cleanup_strv_free_ char **l = NULL;
_cleanup_free_ void *datagram = NULL;
_cleanup_close_ int passed_fd = -EBADF;
struct ucred sender = UCRED_INVALID;
Manager *m = ASSERT_PTR(userdata);
ssize_t n;
Home *h;
int r;
assert(s);
n = read_datagram(fd, &sender, &datagram, &passed_fd);
if (n < 0) {
if (ERRNO_IS_TRANSIENT(n))
return 0;
return log_error_errno(n, "Failed to read notify datagram: %m");
}
_cleanup_(fdset_free_asyncp) FDSet *passed_fds = NULL;
_cleanup_(pidref_done) PidRef sender = PIDREF_NULL;
_cleanup_strv_free_ char **l = NULL;
r = notify_recv_with_fds_strv(fd, &l, /* ret_ucred= */ NULL, &sender, &passed_fds);
if (r == -EAGAIN)
return 0;
if (r < 0)
return r;
if (sender.pid <= 0) {
log_warning("Received notify datagram without valid sender PID, ignoring.");
if (fdset_size(passed_fds) > 1) {
log_warning("Received notify datagram with multiple fds, ignoring.");
return 0;
}
h = hashmap_get(m->homes_by_worker_pid, PID_TO_PTR(sender.pid));
Home *h = hashmap_get(m->homes_by_worker_pid, PID_TO_PTR(sender.pid));
if (!h) {
log_warning("Received notify datagram of unknown process, ignoring.");
return 0;
}
l = strv_split(datagram, "\n");
if (!l)
return log_oom();
home_process_notify(h, l, TAKE_FD(passed_fd));
home_process_notify(h, l, fdset_steal_first(passed_fds));
return 0;
}
@ -1224,7 +1135,11 @@ static int manager_listen_notify(Manager *m) {
r = setsockopt_int(fd, SOL_SOCKET, SO_PASSCRED, true);
if (r < 0)
return r;
return log_error_errno(r, "Failed to enable SO_PASSCRED on notify socket: %m");
r = setsockopt_int(fd, SOL_SOCKET, SO_PASSPIDFD, true);
if (r < 0)
log_warning_errno(r, "Failed to enable SO_PASSPIDFD on notify socket, ignoring: %m");
r = sd_event_add_io(m->event, &m->notify_socket_event_source, fd, EPOLLIN, on_notify_socket, m);
if (r < 0)