1 /* $OpenBSD: control.c,v 1.23 2024年11月21日 13:35:20 claudio Exp $ */ 2 3 /* 4 * Copyright (c) 2003, 2004 Henning Brauer <henning@openbsd.org> 5 * 6 * Permission to use, copy, modify, and distribute this software for any 7 * purpose with or without fee is hereby granted, provided that the above 8 * copyright notice and this permission notice appear in all copies. 9 * 10 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES 11 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF 12 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR 13 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES 14 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN 15 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF 16 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. 17 */ 18#include <sys/types.h> 19#include <sys/queue.h> 20#include <sys/stat.h> 21#include <sys/socket.h> 22#include <sys/time.h> 23#include <sys/un.h> 24 25#include <net/route.h> 26 27#include <errno.h> 28#include <event.h> 29#include <imsg.h> 30#include <stdlib.h> 31#include <string.h> 32#include <unistd.h> 33 34#include "log.h" 35#include "unwind.h" 36#include "control.h" 37#include "frontend.h" 38#include "resolver.h" 39 40#define CONTROL_BACKLOG 5 41 42 struct { 43 struct event ev; 44 struct event evt; 45 int fd; 46} control_state = {.fd = -1}; 47 48 struct ctl_conn { 49 TAILQ_ENTRY(ctl_conn) entry; 50 struct imsgev iev; 51}; 52 53 TAILQ_HEAD(ctl_conns, ctl_conn) ctl_conns = TAILQ_HEAD_INITIALIZER(ctl_conns); 54 55 struct ctl_conn *control_connbyfd(int); 56 struct ctl_conn *control_connbypid(pid_t); 57 void control_close(int); 58 59 int 60 control_init(char *path) 61{ 62 struct sockaddr_un sun; 63 int fd; 64 mode_t old_umask; 65 66 if ((fd = socket(AF_UNIX, SOCK_STREAM | SOCK_CLOEXEC | SOCK_NONBLOCK, 67 0)) == -1) { 68 log_warn("%s: socket", __func__); 69 return (-1); 70 } 71 72 memset(&sun, 0, sizeof(sun)); 73 sun.sun_family = AF_UNIX; 74 strlcpy(sun.sun_path, path, sizeof(sun.sun_path)); 75 76 if (unlink(path) == -1) 77 if (errno != ENOENT) { 78 log_warn("%s: unlink %s", __func__, path); 79 close(fd); 80 return (-1); 81 } 82 83 old_umask = umask(S_IXUSR|S_IXGRP|S_IWOTH|S_IROTH|S_IXOTH); 84 if (bind(fd, (struct sockaddr *)&sun, sizeof(sun)) == -1) { 85 log_warn("%s: bind: %s", __func__, path); 86 close(fd); 87 umask(old_umask); 88 return (-1); 89 } 90 umask(old_umask); 91 92 if (chmod(path, 93 S_IRUSR|S_IWUSR|S_IRGRP|S_IWGRP|S_IROTH|S_IWOTH) == -1) { 94 log_warn("%s: chmod", __func__); 95 close(fd); 96 (void)unlink(path); 97 return (-1); 98 } 99 100 return (fd); 101} 102 103 int 104 control_listen(int fd) 105{ 106 if (control_state.fd != -1) 107 fatalx("%s: received unexpected controlsock", __func__); 108 109 control_state.fd = fd; 110 if (listen(control_state.fd, CONTROL_BACKLOG) == -1) { 111 log_warn("%s: listen", __func__); 112 return (-1); 113 } 114 115 event_set(&control_state.ev, control_state.fd, EV_READ, 116 control_accept, NULL); 117 event_add(&control_state.ev, NULL); 118 evtimer_set(&control_state.evt, control_accept, NULL); 119 120 return (0); 121} 122 123 void 124 control_accept(int listenfd, short event, void *bula) 125{ 126 int connfd; 127 socklen_t len; 128 struct sockaddr_un sun; 129 struct ctl_conn *c; 130 131 event_add(&control_state.ev, NULL); 132 if ((event & EV_TIMEOUT)) 133 return; 134 135 len = sizeof(sun); 136 if ((connfd = accept4(listenfd, (struct sockaddr *)&sun, &len, 137 SOCK_CLOEXEC | SOCK_NONBLOCK)) == -1) { 138 /* 139 * Pause accept if we are out of file descriptors, or 140 * libevent will haunt us here too. 141 */ 142 if (errno == ENFILE || errno == EMFILE) { 143 struct timeval evtpause = { 1, 0 }; 144 145 event_del(&control_state.ev); 146 evtimer_add(&control_state.evt, &evtpause); 147 } else if (errno != EWOULDBLOCK && errno != EINTR && 148 errno != ECONNABORTED) 149 log_warn("%s: accept4", __func__); 150 return; 151 } 152 153 if ((c = calloc(1, sizeof(struct ctl_conn))) == NULL) { 154 log_warn("%s: calloc", __func__); 155 close(connfd); 156 return; 157 } 158 159 if (imsgbuf_init(&c->iev.ibuf, connfd) == -1) { 160 log_warn("%s: imsgbuf_init", __func__); 161 close(connfd); 162 free(c); 163 return; 164 } 165 c->iev.handler = control_dispatch_imsg; 166 c->iev.events = EV_READ; 167 event_set(&c->iev.ev, c->iev.ibuf.fd, c->iev.events, c->iev.handler, 168 &c->iev); 169 event_add(&c->iev.ev, NULL); 170 171 TAILQ_INSERT_TAIL(&ctl_conns, c, entry); 172} 173 174 struct ctl_conn * 175 control_connbyfd(int fd) 176{ 177 struct ctl_conn *c; 178 179 TAILQ_FOREACH(c, &ctl_conns, entry) { 180 if (c->iev.ibuf.fd == fd) 181 break; 182 } 183 184 return (c); 185} 186 187 struct ctl_conn * 188 control_connbypid(pid_t pid) 189{ 190 struct ctl_conn *c; 191 192 TAILQ_FOREACH(c, &ctl_conns, entry) { 193 if (c->iev.ibuf.pid == pid) 194 break; 195 } 196 197 return (c); 198} 199 200 void 201 control_close(int fd) 202{ 203 struct ctl_conn *c; 204 205 if ((c = control_connbyfd(fd)) == NULL) { 206 log_warnx("%s: fd %d: not found", __func__, fd); 207 return; 208 } 209 210 imsgbuf_clear(&c->iev.ibuf); 211 TAILQ_REMOVE(&ctl_conns, c, entry); 212 213 event_del(&c->iev.ev); 214 close(c->iev.ibuf.fd); 215 216 /* Some file descriptors are available again. */ 217 if (evtimer_pending(&control_state.evt, NULL)) { 218 evtimer_del(&control_state.evt); 219 event_add(&control_state.ev, NULL); 220 } 221 222 free(c); 223} 224 225 void 226 control_dispatch_imsg(int fd, short event, void *bula) 227{ 228 struct ctl_conn *c; 229 struct imsg imsg; 230 ssize_t n; 231 int verbose; 232 uid_t euid; 233 gid_t egid; 234 235 if ((c = control_connbyfd(fd)) == NULL) { 236 log_warnx("%s: fd %d: not found", __func__, fd); 237 return; 238 } 239 240 if (event & EV_READ) { 241 if (imsgbuf_read(&c->iev.ibuf) != 1) { 242 control_close(fd); 243 return; 244 } 245 } 246 if (event & EV_WRITE) { 247 if (imsgbuf_write(&c->iev.ibuf) == -1) { 248 control_close(fd); 249 return; 250 } 251 } 252 253 if (getpeereid(fd, &euid, &egid) == -1) { 254 control_close(fd); 255 return; 256 } 257 258 for (;;) { 259 if ((n = imsg_get(&c->iev.ibuf, &imsg)) == -1) { 260 control_close(fd); 261 return; 262 } 263 if (n == 0) 264 break; 265 266 switch (imsg.hdr.type) { 267 case IMSG_CTL_LOG_VERBOSE: 268 case IMSG_CTL_RELOAD: 269 if (euid != 0) { 270 imsg_free(&imsg); 271 control_close(fd); 272 return; 273 } 274 break; 275 default: 276 break; 277 } 278 279 c->iev.ibuf.pid = imsg.hdr.pid; 280 switch (imsg.hdr.type) { 281 case IMSG_CTL_RELOAD: 282 frontend_imsg_compose_main(imsg.hdr.type, imsg.hdr.pid, 283 NULL, 0); 284 break; 285 case IMSG_CTL_LOG_VERBOSE: 286 if (IMSG_DATA_SIZE(imsg) != sizeof(verbose)) 287 break; 288 289 /* Forward to all other processes. */ 290 frontend_imsg_compose_main(imsg.hdr.type, imsg.hdr.pid, 291 imsg.data, IMSG_DATA_SIZE(imsg)); 292 frontend_imsg_compose_resolver(imsg.hdr.type, 293 imsg.hdr.pid, imsg.data, IMSG_DATA_SIZE(imsg)); 294 295 memcpy(&verbose, imsg.data, sizeof(verbose)); 296 log_setverbose(verbose); 297 break; 298 case IMSG_CTL_STATUS: 299 case IMSG_CTL_AUTOCONF: 300 case IMSG_CTL_MEM: 301 if (IMSG_DATA_SIZE(imsg) != 0) 302 break; 303 frontend_imsg_compose_resolver(imsg.hdr.type, 304 imsg.hdr.pid, NULL, 0); 305 break; 306 default: 307 log_debug("%s: error handling imsg %d", __func__, 308 imsg.hdr.type); 309 break; 310 } 311 imsg_free(&imsg); 312 } 313 314 imsg_event_add(&c->iev); 315} 316 317 int 318 control_imsg_relay(struct imsg *imsg) 319{ 320 struct ctl_conn *c; 321 322 if ((c = control_connbypid(imsg->hdr.pid)) == NULL) 323 return (0); 324 325 return (imsg_compose_event(&c->iev, imsg->hdr.type, 0, imsg->hdr.pid, 326 -1, imsg->data, IMSG_DATA_SIZE(*imsg))); 327} 328