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-rw-r--r--lib/zlog_live.c266
1 files changed, 266 insertions, 0 deletions
diff --git a/lib/zlog_live.c b/lib/zlog_live.c
new file mode 100644
index 0000000..4d3c350
--- /dev/null
+++ b/lib/zlog_live.c
@@ -0,0 +1,266 @@
+// SPDX-License-Identifier: ISC
+/*
+ * Copyright (c) 2019-22 David Lamparter, for NetDEF, Inc.
+ */
+
+#include "zebra.h"
+
+#include "zlog_live.h"
+
+#include "memory.h"
+#include "frrcu.h"
+#include "zlog.h"
+#include "printfrr.h"
+#include "network.h"
+
+DEFINE_MTYPE_STATIC(LOG, LOG_LIVE, "log vtysh live target");
+
+enum {
+ STATE_NORMAL = 0,
+ STATE_FD_DEAD,
+ STATE_DISOWNED,
+};
+
+struct zlt_live {
+ struct zlog_target zt;
+
+ atomic_uint_fast32_t fd;
+ struct rcu_head_close head_close;
+ struct rcu_head head_self;
+
+ atomic_uint_fast32_t state;
+ atomic_uint_fast32_t lost_msgs;
+};
+
+static void zlog_live(struct zlog_target *zt, struct zlog_msg *msgs[],
+ size_t nmsgs)
+{
+ struct zlt_live *zte = container_of(zt, struct zlt_live, zt);
+ struct zlog_live_hdr hdrs[nmsgs], *hdr = hdrs;
+ struct mmsghdr mmhs[nmsgs], *mmh = mmhs;
+ struct iovec iovs[nmsgs * 3], *iov = iovs;
+ struct timespec ts;
+ size_t i, textlen;
+ int fd;
+ uint_fast32_t state;
+
+ fd = atomic_load_explicit(&zte->fd, memory_order_relaxed);
+
+ if (fd < 0)
+ return;
+
+ memset(mmhs, 0, sizeof(mmhs));
+ memset(hdrs, 0, sizeof(hdrs));
+
+ for (i = 0; i < nmsgs; i++) {
+ const struct fmt_outpos *argpos;
+ size_t n_argpos, texthdrlen;
+ struct zlog_msg *msg = msgs[i];
+ int prio = zlog_msg_prio(msg);
+ const struct xref_logmsg *xref;
+ intmax_t pid, tid;
+
+ if (prio > zt->prio_min)
+ continue;
+
+ zlog_msg_args(msg, &texthdrlen, &n_argpos, &argpos);
+
+ mmh->msg_hdr.msg_iov = iov;
+
+ iov->iov_base = hdr;
+ iov->iov_len = sizeof(*hdr);
+ iov++;
+
+ if (n_argpos) {
+ iov->iov_base = (char *)argpos;
+ iov->iov_len = sizeof(*argpos) * n_argpos;
+ iov++;
+ }
+
+ iov->iov_base = (char *)zlog_msg_text(msg, &textlen);
+ iov->iov_len = textlen;
+ iov++;
+
+ zlog_msg_tsraw(msg, &ts);
+ zlog_msg_pid(msg, &pid, &tid);
+ xref = zlog_msg_xref(msg);
+
+ hdr->ts_sec = ts.tv_sec;
+ hdr->ts_nsec = ts.tv_nsec;
+ hdr->pid = pid;
+ hdr->tid = tid;
+ hdr->lost_msgs = atomic_load_explicit(&zte->lost_msgs,
+ memory_order_relaxed);
+ hdr->prio = prio;
+ hdr->flags = 0;
+ hdr->textlen = textlen;
+ hdr->texthdrlen = texthdrlen;
+ hdr->n_argpos = n_argpos;
+ if (xref) {
+ memcpy(hdr->uid, xref->xref.xrefdata->uid,
+ sizeof(hdr->uid));
+ hdr->ec = xref->ec;
+ } else {
+ memset(hdr->uid, 0, sizeof(hdr->uid));
+ hdr->ec = 0;
+ }
+ hdr->hdrlen = sizeof(*hdr) + sizeof(*argpos) * n_argpos;
+
+ mmh->msg_hdr.msg_iovlen = iov - mmh->msg_hdr.msg_iov;
+ mmh++;
+ hdr++;
+ }
+
+ size_t msgtotal = mmh - mmhs;
+ ssize_t sent;
+
+ for (size_t msgpos = 0; msgpos < msgtotal; msgpos += sent) {
+ sent = sendmmsg(fd, mmhs + msgpos, msgtotal - msgpos, 0);
+
+ if (sent <= 0 && (errno == EAGAIN || errno == EWOULDBLOCK)) {
+ atomic_fetch_add_explicit(&zte->lost_msgs,
+ msgtotal - msgpos,
+ memory_order_relaxed);
+ break;
+ }
+ if (sent <= 0)
+ goto out_err;
+ }
+ return;
+
+out_err:
+ fd = atomic_exchange_explicit(&zte->fd, -1, memory_order_relaxed);
+ if (fd < 0)
+ return;
+
+ rcu_close(&zte->head_close, fd);
+ zlog_target_replace(zt, NULL);
+
+ state = STATE_NORMAL;
+ atomic_compare_exchange_strong_explicit(
+ &zte->state, &state, STATE_FD_DEAD, memory_order_relaxed,
+ memory_order_relaxed);
+ if (state == STATE_DISOWNED)
+ rcu_free(MTYPE_LOG_LIVE, zte, head_self);
+}
+
+static void zlog_live_sigsafe(struct zlog_target *zt, const char *text,
+ size_t len)
+{
+ struct zlt_live *zte = container_of(zt, struct zlt_live, zt);
+ struct zlog_live_hdr hdr[1] = {};
+ struct iovec iovs[2], *iov = iovs;
+ struct timespec ts;
+ int fd;
+
+ fd = atomic_load_explicit(&zte->fd, memory_order_relaxed);
+ if (fd < 0)
+ return;
+
+ clock_gettime(CLOCK_REALTIME, &ts);
+
+ hdr->ts_sec = ts.tv_sec;
+ hdr->ts_nsec = ts.tv_nsec;
+ hdr->prio = LOG_CRIT;
+ hdr->textlen = len;
+
+ iov->iov_base = (char *)hdr;
+ iov->iov_len = sizeof(hdr);
+ iov++;
+
+ iov->iov_base = (char *)text;
+ iov->iov_len = len;
+ iov++;
+
+ writev(fd, iovs, iov - iovs);
+}
+
+void zlog_live_open(struct zlog_live_cfg *cfg, int prio_min, int *other_fd)
+{
+ int sockets[2];
+
+ if (cfg->target)
+ zlog_live_close(cfg);
+
+ *other_fd = -1;
+ if (prio_min == ZLOG_DISABLED)
+ return;
+
+ /* the only reason for SEQPACKET here is getting close notifications.
+ * otherwise if you open a bunch of vtysh connections with live logs
+ * and close them all, the fds will stick around until we get an error
+ * when trying to log something to them at some later point -- which
+ * eats up fds and might be *much* later for some daemons.
+ */
+ if (socketpair(AF_UNIX, SOCK_SEQPACKET, 0, sockets) < 0) {
+ if (socketpair(AF_UNIX, SOCK_DGRAM, 0, sockets) < 0) {
+ zlog_warn("%% could not open socket pair: %m");
+ return;
+ }
+ } else
+ /* SEQPACKET only: try to zap read direction */
+ shutdown(sockets[0], SHUT_RD);
+
+ *other_fd = sockets[1];
+ zlog_live_open_fd(cfg, prio_min, sockets[0]);
+}
+
+void zlog_live_open_fd(struct zlog_live_cfg *cfg, int prio_min, int fd)
+{
+ struct zlt_live *zte;
+ struct zlog_target *zt;
+
+ if (cfg->target)
+ zlog_live_close(cfg);
+
+ zt = zlog_target_clone(MTYPE_LOG_LIVE, NULL, sizeof(*zte));
+ zte = container_of(zt, struct zlt_live, zt);
+ cfg->target = zte;
+
+ set_nonblocking(fd);
+ zte->fd = fd;
+ zte->zt.prio_min = prio_min;
+ zte->zt.logfn = zlog_live;
+ zte->zt.logfn_sigsafe = zlog_live_sigsafe;
+
+ zlog_target_replace(NULL, zt);
+}
+
+void zlog_live_close(struct zlog_live_cfg *cfg)
+{
+ struct zlt_live *zte;
+ int fd;
+
+ if (!cfg->target)
+ return;
+
+ zte = cfg->target;
+ cfg->target = NULL;
+
+ fd = atomic_exchange_explicit(&zte->fd, -1, memory_order_relaxed);
+
+ if (fd >= 0) {
+ rcu_close(&zte->head_close, fd);
+ zlog_target_replace(&zte->zt, NULL);
+ }
+ rcu_free(MTYPE_LOG_LIVE, zte, head_self);
+}
+
+void zlog_live_disown(struct zlog_live_cfg *cfg)
+{
+ struct zlt_live *zte;
+ uint_fast32_t state;
+
+ if (!cfg->target)
+ return;
+
+ zte = cfg->target;
+ cfg->target = NULL;
+
+ state = STATE_NORMAL;
+ atomic_compare_exchange_strong_explicit(
+ &zte->state, &state, STATE_DISOWNED, memory_order_relaxed,
+ memory_order_relaxed);
+ if (state == STATE_FD_DEAD)
+ rcu_free(MTYPE_LOG_LIVE, zte, head_self);
+}
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-23 09:19:09 +0000