journald: minor modernizations in kmsg handling code

Nothing earth shattering. Mostly just fixes (and some more careful
checking of the boolean variables we keep)
This commit is contained in:
Lennart Poettering 2023-01-26 10:10:20 +01:00
parent 50bf54ad0a
commit 208ff21a40

View file

@ -37,7 +37,7 @@ void server_forward_kmsg(
struct iovec iovec[5];
char header_priority[DECIMAL_STR_MAX(priority) + 3],
header_pid[STRLEN("[]: ") + DECIMAL_STR_MAX(pid_t) + 1];
int n = 0;
size_t n = 0;
assert(s);
assert(priority >= 0);
@ -65,11 +65,10 @@ void server_forward_kmsg(
identifier = ident_buf;
}
xsprintf(header_pid, "["PID_FMT"]: ", ucred->pid);
if (identifier)
iovec[n++] = IOVEC_MAKE_STRING(identifier);
xsprintf(header_pid, "["PID_FMT"]: ", ucred->pid);
iovec[n++] = IOVEC_MAKE_STRING(header_pid);
} else if (identifier) {
iovec[n++] = IOVEC_MAKE_STRING(identifier);
@ -81,7 +80,7 @@ void server_forward_kmsg(
iovec[n++] = IOVEC_MAKE_STRING("\n");
if (writev(s->dev_kmsg_fd, iovec, n) < 0)
log_debug_errno(errno, "Failed to write to /dev/kmsg for logging: %m");
log_debug_errno(errno, "Failed to write to /dev/kmsg for logging, ignoring: %m");
}
static bool is_us(const char *identifier, const char *pid) {
@ -297,7 +296,6 @@ void dev_kmsg_record(Server *s, char *p, size_t l) {
if (cunescape_length_with_prefix(p, pl, "MESSAGE=", UNESCAPE_RELAX, &message) >= 0)
iovec[n++] = IOVEC_MAKE_STRING(message);
server_dispatch_message(s, iovec, n, ELEMENTSOF(iovec), c, NULL, priority, 0);
if (saved_log_max_level != INT_MAX)
@ -319,11 +317,11 @@ static int server_read_dev_kmsg(Server *s) {
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't try to ever read from it again. */
/* Old kernels which don't allow reading from /dev/kmsg return EINVAL when we try. So handle
* this cleanly, but don't try to ever read from it again. */
if (errno == EINVAL) {
s->dev_kmsg_event_source = sd_event_source_unref(s->dev_kmsg_event_source);
s->dev_kmsg_readable = false;
return 0;
}
@ -400,33 +398,27 @@ int server_open_dev_kmsg(Server *s) {
return 0;
r = sd_event_add_io(s->event, &s->dev_kmsg_event_source, s->dev_kmsg_fd, EPOLLIN, dispatch_dev_kmsg, s);
if (r == -EPERM) { /* This will fail with EPERM on older kernels where /dev/kmsg is not readable. */
r = 0;
goto finish;
}
if (r < 0) {
/* This will fail with EPERM on older kernels where
* /dev/kmsg is not readable. */
if (r == -EPERM) {
r = 0;
goto fail;
}
log_error_errno(r, "Failed to add /dev/kmsg fd to event loop: %m");
goto fail;
goto finish;
}
r = sd_event_source_set_priority(s->dev_kmsg_event_source, SD_EVENT_PRIORITY_IMPORTANT+10);
if (r < 0) {
log_error_errno(r, "Failed to adjust priority of kmsg event source: %m");
goto fail;
goto finish;
}
s->dev_kmsg_readable = true;
return 0;
fail:
finish:
s->dev_kmsg_event_source = sd_event_source_unref(s->dev_kmsg_event_source);
s->dev_kmsg_fd = safe_close(s->dev_kmsg_fd);
return r;
}
@ -441,7 +433,7 @@ int server_open_kernel_seqnum(Server *s) {
/* We store the seqnum we last read in an mmapped file. That way we can just use it like a variable,
* but it is persistent and automatically flushed at reboot. */
if (!s->read_kmsg)
if (!s->dev_kmsg_readable)
return 0;
fn = strjoina(s->runtime_directory, "/kernel-seqnum");