static int server_read_dev_kmsg(Server *s) {
char buffer[8192+1]; /* the kernel-side limit per record is 8K currently */
ssize_t l;
assert(s);
assert(s->dev_kmsg_fd >= 0);
l = read(s->dev_kmsg_fd, buffer, sizeof(buffer) - 1);
if (l == 0)
return 0;
if (l < 0) {
/* Old kernels who don't allow reading from /dev/kmsg
* return EINVAL when we try. So handle this cleanly,
* but don' try to ever read from it again. */
if (errno == EINVAL) {
s->dev_kmsg_event_source = sd_event_source_unref(s->dev_kmsg_event_source);
return 0;
}
if (IN_SET(errno, EAGAIN, EINTR, EPIPE))
return 0;
return log_error_errno(errno, "Failed to read from kernel: %m");
}
dev_kmsg_record(s, buffer, l);
return 1;
}
int server_read_dev_kmsg(Server *s) {
char buffer[8192+1]; /* the kernel-side limit per record is 8K currently */
ssize_t l;
assert(s);
assert(s->dev_kmsg_fd >= 0);
l = read(s->dev_kmsg_fd, buffer, sizeof(buffer) - 1);
if (l == 0)
return 0;
if (l < 0) {
/* Old kernels who don't allow reading from /dev/kmsg
* return EINVAL when we try. So handle this cleanly,
* but don' try to ever read from it again. */
if (errno == EINVAL) {
epoll_ctl(s->epoll_fd, EPOLL_CTL_DEL, s->dev_kmsg_fd, NULL);
return 0;
}
if (errno == EAGAIN || errno == EINTR || errno == EPIPE)
return 0;
log_error("Failed to read from kernel: %m");
return -errno;
}
dev_kmsg_record(s, buffer, l);
return 1;
}