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0798d276 DL |
1 | /* |
2 | * Copyright (c) 2019-22 David Lamparter, for NetDEF, Inc. | |
3 | * | |
4 | * Permission to use, copy, modify, and distribute this software for any | |
5 | * purpose with or without fee is hereby granted, provided that the above | |
6 | * copyright notice and this permission notice appear in all copies. | |
7 | * | |
8 | * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES | |
9 | * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF | |
10 | * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR | |
11 | * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES | |
12 | * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN | |
13 | * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF | |
14 | * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. | |
15 | */ | |
16 | ||
17 | #include "zebra.h" | |
18 | ||
19 | #include "zlog_live.h" | |
20 | ||
21 | #include "memory.h" | |
22 | #include "frrcu.h" | |
23 | #include "zlog.h" | |
24 | #include "printfrr.h" | |
2eda953a | 25 | #include "network.h" |
0798d276 DL |
26 | |
27 | DEFINE_MTYPE_STATIC(LOG, LOG_LIVE, "log vtysh live target"); | |
28 | ||
29 | enum { | |
30 | STATE_NORMAL = 0, | |
31 | STATE_FD_DEAD, | |
32 | STATE_DISOWNED, | |
33 | }; | |
34 | ||
35 | struct zlt_live { | |
36 | struct zlog_target zt; | |
37 | ||
38 | atomic_uint_fast32_t fd; | |
39 | struct rcu_head_close head_close; | |
40 | struct rcu_head head_self; | |
41 | ||
42 | atomic_uint_fast32_t state; | |
a4af82ee | 43 | atomic_uint_fast32_t lost_msgs; |
0798d276 DL |
44 | }; |
45 | ||
46 | static void zlog_live(struct zlog_target *zt, struct zlog_msg *msgs[], | |
47 | size_t nmsgs) | |
48 | { | |
49 | struct zlt_live *zte = container_of(zt, struct zlt_live, zt); | |
50 | struct zlog_live_hdr hdrs[nmsgs], *hdr = hdrs; | |
51 | struct mmsghdr mmhs[nmsgs], *mmh = mmhs; | |
52 | struct iovec iovs[nmsgs * 3], *iov = iovs; | |
53 | struct timespec ts; | |
54 | size_t i, textlen; | |
55 | int fd; | |
56 | uint_fast32_t state; | |
57 | ||
58 | fd = atomic_load_explicit(&zte->fd, memory_order_relaxed); | |
59 | ||
60 | if (fd < 0) | |
61 | return; | |
62 | ||
63 | memset(mmhs, 0, sizeof(mmhs)); | |
64 | memset(hdrs, 0, sizeof(hdrs)); | |
65 | ||
66 | for (i = 0; i < nmsgs; i++) { | |
67 | const struct fmt_outpos *argpos; | |
834585bd | 68 | size_t n_argpos, texthdrlen; |
0798d276 DL |
69 | struct zlog_msg *msg = msgs[i]; |
70 | int prio = zlog_msg_prio(msg); | |
834585bd DL |
71 | const struct xref_logmsg *xref; |
72 | intmax_t pid, tid; | |
0798d276 DL |
73 | |
74 | if (prio > zt->prio_min) | |
75 | continue; | |
76 | ||
834585bd | 77 | zlog_msg_args(msg, &texthdrlen, &n_argpos, &argpos); |
0798d276 DL |
78 | |
79 | mmh->msg_hdr.msg_iov = iov; | |
80 | ||
81 | iov->iov_base = hdr; | |
82 | iov->iov_len = sizeof(*hdr); | |
83 | iov++; | |
84 | ||
85 | if (n_argpos) { | |
86 | iov->iov_base = (char *)argpos; | |
87 | iov->iov_len = sizeof(*argpos) * n_argpos; | |
88 | iov++; | |
89 | } | |
90 | ||
91 | iov->iov_base = (char *)zlog_msg_text(msg, &textlen); | |
92 | iov->iov_len = textlen; | |
93 | iov++; | |
94 | ||
95 | zlog_msg_tsraw(msg, &ts); | |
834585bd DL |
96 | zlog_msg_pid(msg, &pid, &tid); |
97 | xref = zlog_msg_xref(msg); | |
0798d276 DL |
98 | |
99 | hdr->ts_sec = ts.tv_sec; | |
100 | hdr->ts_nsec = ts.tv_nsec; | |
834585bd DL |
101 | hdr->pid = pid; |
102 | hdr->tid = tid; | |
a4af82ee DL |
103 | hdr->lost_msgs = atomic_load_explicit(&zte->lost_msgs, |
104 | memory_order_relaxed); | |
834585bd | 105 | hdr->prio = prio; |
0798d276 DL |
106 | hdr->flags = 0; |
107 | hdr->textlen = textlen; | |
834585bd | 108 | hdr->texthdrlen = texthdrlen; |
0798d276 | 109 | hdr->n_argpos = n_argpos; |
834585bd DL |
110 | if (xref) { |
111 | memcpy(hdr->uid, xref->xref.xrefdata->uid, | |
112 | sizeof(hdr->uid)); | |
113 | hdr->ec = xref->ec; | |
114 | } else { | |
115 | memset(hdr->uid, 0, sizeof(hdr->uid)); | |
116 | hdr->ec = 0; | |
117 | } | |
118 | hdr->hdrlen = sizeof(*hdr) + sizeof(*argpos) * n_argpos; | |
0798d276 DL |
119 | |
120 | mmh->msg_hdr.msg_iovlen = iov - mmh->msg_hdr.msg_iov; | |
121 | mmh++; | |
122 | hdr++; | |
123 | } | |
124 | ||
125 | size_t msgtotal = mmh - mmhs; | |
126 | ssize_t sent; | |
127 | ||
128 | for (size_t msgpos = 0; msgpos < msgtotal; msgpos += sent) { | |
129 | sent = sendmmsg(fd, mmhs + msgpos, msgtotal - msgpos, 0); | |
130 | ||
a4af82ee DL |
131 | if (sent <= 0 && (errno == EAGAIN || errno == EWOULDBLOCK)) { |
132 | atomic_fetch_add_explicit(&zte->lost_msgs, | |
133 | msgtotal - msgpos, | |
134 | memory_order_relaxed); | |
2eda953a | 135 | break; |
a4af82ee | 136 | } |
0798d276 DL |
137 | if (sent <= 0) |
138 | goto out_err; | |
139 | } | |
140 | return; | |
141 | ||
142 | out_err: | |
143 | fd = atomic_exchange_explicit(&zte->fd, -1, memory_order_relaxed); | |
144 | if (fd < 0) | |
145 | return; | |
146 | ||
147 | rcu_close(&zte->head_close, fd); | |
148 | zlog_target_replace(zt, NULL); | |
149 | ||
150 | state = STATE_NORMAL; | |
151 | atomic_compare_exchange_strong_explicit( | |
152 | &zte->state, &state, STATE_FD_DEAD, memory_order_relaxed, | |
153 | memory_order_relaxed); | |
154 | if (state == STATE_DISOWNED) | |
155 | rcu_free(MTYPE_LOG_LIVE, zte, head_self); | |
156 | } | |
157 | ||
158 | static void zlog_live_sigsafe(struct zlog_target *zt, const char *text, | |
159 | size_t len) | |
160 | { | |
161 | struct zlt_live *zte = container_of(zt, struct zlt_live, zt); | |
1609a9d6 | 162 | struct zlog_live_hdr hdr[1] = {}; |
0798d276 DL |
163 | struct iovec iovs[2], *iov = iovs; |
164 | struct timespec ts; | |
165 | int fd; | |
166 | ||
167 | fd = atomic_load_explicit(&zte->fd, memory_order_relaxed); | |
168 | if (fd < 0) | |
169 | return; | |
170 | ||
1609a9d6 | 171 | clock_gettime(CLOCK_REALTIME, &ts); |
0798d276 DL |
172 | |
173 | hdr->ts_sec = ts.tv_sec; | |
174 | hdr->ts_nsec = ts.tv_nsec; | |
175 | hdr->prio = LOG_CRIT; | |
0798d276 | 176 | hdr->textlen = len; |
0798d276 DL |
177 | |
178 | iov->iov_base = (char *)hdr; | |
179 | iov->iov_len = sizeof(hdr); | |
180 | iov++; | |
181 | ||
182 | iov->iov_base = (char *)text; | |
183 | iov->iov_len = len; | |
184 | iov++; | |
185 | ||
186 | writev(fd, iovs, iov - iovs); | |
187 | } | |
188 | ||
189 | void zlog_live_open(struct zlog_live_cfg *cfg, int prio_min, int *other_fd) | |
190 | { | |
191 | int sockets[2]; | |
0798d276 DL |
192 | |
193 | if (cfg->target) | |
194 | zlog_live_close(cfg); | |
195 | ||
196 | *other_fd = -1; | |
197 | if (prio_min == ZLOG_DISABLED) | |
198 | return; | |
199 | ||
200 | /* the only reason for SEQPACKET here is getting close notifications. | |
201 | * otherwise if you open a bunch of vtysh connections with live logs | |
202 | * and close them all, the fds will stick around until we get an error | |
203 | * when trying to log something to them at some later point -- which | |
204 | * eats up fds and might be *much* later for some daemons. | |
205 | */ | |
206 | if (socketpair(AF_UNIX, SOCK_SEQPACKET, 0, sockets) < 0) { | |
207 | if (socketpair(AF_UNIX, SOCK_DGRAM, 0, sockets) < 0) { | |
208 | zlog_warn("%% could not open socket pair: %m"); | |
209 | return; | |
210 | } | |
211 | } else | |
212 | /* SEQPACKET only: try to zap read direction */ | |
213 | shutdown(sockets[0], SHUT_RD); | |
214 | ||
215 | *other_fd = sockets[1]; | |
3bcdae10 DL |
216 | zlog_live_open_fd(cfg, prio_min, sockets[0]); |
217 | } | |
218 | ||
219 | void zlog_live_open_fd(struct zlog_live_cfg *cfg, int prio_min, int fd) | |
220 | { | |
221 | struct zlt_live *zte; | |
222 | struct zlog_target *zt; | |
223 | ||
224 | if (cfg->target) | |
225 | zlog_live_close(cfg); | |
0798d276 DL |
226 | |
227 | zt = zlog_target_clone(MTYPE_LOG_LIVE, NULL, sizeof(*zte)); | |
228 | zte = container_of(zt, struct zlt_live, zt); | |
229 | cfg->target = zte; | |
230 | ||
3bcdae10 DL |
231 | set_nonblocking(fd); |
232 | zte->fd = fd; | |
0798d276 DL |
233 | zte->zt.prio_min = prio_min; |
234 | zte->zt.logfn = zlog_live; | |
235 | zte->zt.logfn_sigsafe = zlog_live_sigsafe; | |
236 | ||
237 | zlog_target_replace(NULL, zt); | |
238 | } | |
239 | ||
240 | void zlog_live_close(struct zlog_live_cfg *cfg) | |
241 | { | |
242 | struct zlt_live *zte; | |
243 | int fd; | |
244 | ||
245 | if (!cfg->target) | |
246 | return; | |
247 | ||
248 | zte = cfg->target; | |
249 | cfg->target = NULL; | |
250 | ||
251 | fd = atomic_exchange_explicit(&zte->fd, -1, memory_order_relaxed); | |
252 | ||
253 | if (fd >= 0) { | |
254 | rcu_close(&zte->head_close, fd); | |
255 | zlog_target_replace(&zte->zt, NULL); | |
256 | } | |
257 | rcu_free(MTYPE_LOG_LIVE, zte, head_self); | |
258 | } | |
259 | ||
260 | void zlog_live_disown(struct zlog_live_cfg *cfg) | |
261 | { | |
262 | struct zlt_live *zte; | |
263 | uint_fast32_t state; | |
264 | ||
265 | if (!cfg->target) | |
266 | return; | |
267 | ||
268 | zte = cfg->target; | |
269 | cfg->target = NULL; | |
270 | ||
271 | state = STATE_NORMAL; | |
272 | atomic_compare_exchange_strong_explicit( | |
273 | &zte->state, &state, STATE_DISOWNED, memory_order_relaxed, | |
274 | memory_order_relaxed); | |
275 | if (state == STATE_FD_DEAD) | |
276 | rcu_free(MTYPE_LOG_LIVE, zte, head_self); | |
277 | } |