src/journal/journald-syslog.c

   1 /*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
   2
   3 /***
   4   This file is part of systemd.
   5
   6   Copyright 2011 Lennart Poettering
   7
   8   systemd is free software; you can redistribute it and/or modify it
   9   under the terms of the GNU Lesser General Public License as published by
  10   the Free Software Foundation; either version 2.1 of the License, or
  11   (at your option) any later version.
  12
  13   systemd is distributed in the hope that it will be useful, but
  14   WITHOUT ANY WARRANTY; without even the implied warranty of
  15   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  16   Lesser General Public License for more details.
  17
  18   You should have received a copy of the GNU Lesser General Public License
  19   along with systemd; If not, see <http://www.gnu.org/licenses/>.
  20 ***/
  21
  22 #include <unistd.h>
  23 #include <stddef.h>
  24 #include <sys/epoll.h>
  25
  26 #include "systemd/sd-messages.h"
  27 #include "socket-util.h"
  28 #include "selinux-util.h"
  29 #include "journald-server.h"
  30 #include "journald-syslog.h"
  31 #include "journald-kmsg.h"
  32 #include "journald-console.h"
  33 #include "journald-wall.h"
  34
  35 /* Warn once every 30s if we missed syslog message */
  36 #define WARN_FORWARD_SYSLOG_MISSED_USEC (30 * USEC_PER_SEC)
  37
  38 static void forward_syslog_iovec(Server *s, const struct iovec *iovec, unsigned n_iovec, const struct ucred *ucred, const struct timeval *tv) {
  39
  40         static const union sockaddr_union sa = {
  41                 .un.sun_family = AF_UNIX,
  42                 .un.sun_path = "/run/systemd/journal/syslog",
  43         };
  44         struct msghdr msghdr = {
  45                 .msg_iov = (struct iovec *) iovec,
  46                 .msg_iovlen = n_iovec,
  47                 .msg_name = (struct sockaddr*) &sa.sa,
  48                 .msg_namelen = offsetof(union sockaddr_union, un.sun_path)
  49                                + strlen("/run/systemd/journal/syslog"),
  50         };
  51         struct cmsghdr *cmsg;
  52         union {
  53                 struct cmsghdr cmsghdr;
  54                 uint8_t buf[CMSG_SPACE(sizeof(struct ucred))];
  55         } control;
  56
  57         assert(s);
  58         assert(iovec);
  59         assert(n_iovec > 0);
  60
  61         if (ucred) {
  62                 zero(control);
  63                 msghdr.msg_control = &control;
  64                 msghdr.msg_controllen = sizeof(control);
  65
  66                 cmsg = CMSG_FIRSTHDR(&msghdr);
  67                 cmsg->cmsg_level = SOL_SOCKET;
  68                 cmsg->cmsg_type = SCM_CREDENTIALS;
  69                 cmsg->cmsg_len = CMSG_LEN(sizeof(struct ucred));
  70                 memcpy(CMSG_DATA(cmsg), ucred, sizeof(struct ucred));
  71                 msghdr.msg_controllen = cmsg->cmsg_len;
  72         }
  73
  74         /* Forward the syslog message we received via /dev/log to
  75          * /run/systemd/syslog. Unfortunately we currently can't set
  76          * the SO_TIMESTAMP auxiliary data, and hence we don't. */
  77
  78         if (sendmsg(s->syslog_fd, &msghdr, MSG_NOSIGNAL) >= 0)
  79                 return;
  80
  81         /* The socket is full? I guess the syslog implementation is
  82          * too slow, and we shouldn't wait for that... */
  83         if (errno == EAGAIN) {
  84                 s->n_forward_syslog_missed++;
  85                 return;
  86         }
  87
  88         if (ucred && (errno == ESRCH || errno == EPERM)) {
  89                 struct ucred u;
  90
  91                 /* Hmm, presumably the sender process vanished
  92                  * by now, or we don't have CAP_SYS_AMDIN, so
  93                  * let's fix it as good as we can, and retry */
  94
  95                 u = *ucred;
  96                 u.pid = getpid();
  97                 memcpy(CMSG_DATA(cmsg), &u, sizeof(struct ucred));
  98
  99                 if (sendmsg(s->syslog_fd, &msghdr, MSG_NOSIGNAL) >= 0)
 100                         return;
 101
 102                 if (errno == EAGAIN) {
 103                         s->n_forward_syslog_missed++;
 104                         return;
 105                 }
 106         }
 107
 108         if (errno != ENOENT)
 109                 log_debug_errno(errno, "Failed to forward syslog message: %m");
 110 }
 111
 112 static void forward_syslog_raw(Server *s, int priority, const char *buffer, const struct ucred *ucred, const struct timeval *tv) {
 113         struct iovec iovec;
 114
 115         assert(s);
 116         assert(buffer);
 117
 118         if (LOG_PRI(priority) > s->max_level_syslog)
 119                 return;
 120
 121         IOVEC_SET_STRING(iovec, buffer);
 122         forward_syslog_iovec(s, &iovec, 1, ucred, tv);
 123 }
 124
 125 void server_forward_syslog(Server *s, int priority, const char *identifier, const char *message, const struct ucred *ucred, const struct timeval *tv) {
 126         struct iovec iovec[5];
 127         char header_priority[6], header_time[64], header_pid[16];
 128         int n = 0;
 129         time_t t;
 130         struct tm *tm;
 131         char *ident_buf = NULL;
 132
 133         assert(s);
 134         assert(priority >= 0);
 135         assert(priority <= 999);
 136         assert(message);
 137
 138         if (LOG_PRI(priority) > s->max_level_syslog)
 139                 return;
 140
 141         /* First: priority field */
 142         snprintf(header_priority, sizeof(header_priority), "<%i>", priority);
 143         char_array_0(header_priority);
 144         IOVEC_SET_STRING(iovec[n++], header_priority);
 145
 146         /* Second: timestamp */
 147         t = tv ? tv->tv_sec : ((time_t) (now(CLOCK_REALTIME) / USEC_PER_SEC));
 148         tm = localtime(&t);
 149         if (!tm)
 150                 return;
 151         if (strftime(header_time, sizeof(header_time), "%h %e %T ", tm) <= 0)
 152                 return;
 153         IOVEC_SET_STRING(iovec[n++], header_time);
 154
 155         /* Third: identifier and PID */
 156         if (ucred) {
 157                 if (!identifier) {
 158                         get_process_comm(ucred->pid, &ident_buf);
 159                         identifier = ident_buf;
 160                 }
 161
 162                 snprintf(header_pid, sizeof(header_pid), "["PID_FMT"]: ", ucred->pid);
 163                 char_array_0(header_pid);
 164
 165                 if (identifier)
 166                         IOVEC_SET_STRING(iovec[n++], identifier);
 167
 168                 IOVEC_SET_STRING(iovec[n++], header_pid);
 169         } else if (identifier) {
 170                 IOVEC_SET_STRING(iovec[n++], identifier);
 171                 IOVEC_SET_STRING(iovec[n++], ": ");
 172         }
 173
 174         /* Fourth: message */
 175         IOVEC_SET_STRING(iovec[n++], message);
 176
 177         forward_syslog_iovec(s, iovec, n, ucred, tv);
 178
 179         free(ident_buf);
 180 }
 181
 182 int syslog_fixup_facility(int priority) {
 183
 184         if ((priority & LOG_FACMASK) == 0)
 185                 return (priority & LOG_PRIMASK) | LOG_USER;
 186
 187         return priority;
 188 }
 189
 190 size_t syslog_parse_identifier(const char **buf, char **identifier, char **pid) {
 191         const char *p;
 192         char *t;
 193         size_t l, e;
 194
 195         assert(buf);
 196         assert(identifier);
 197         assert(pid);
 198
 199         p = *buf;
 200
 201         p += strspn(p, WHITESPACE);
 202         l = strcspn(p, WHITESPACE);
 203
 204         if (l <= 0 ||
 205             p[l-1] != ':')
 206                 return 0;
 207
 208         e = l;
 209         l--;
 210
 211         if (p[l-1] == ']') {
 212                 size_t k = l-1;
 213
 214                 for (;;) {
 215
 216                         if (p[k] == '[') {
 217                                 t = strndup(p+k+1, l-k-2);
 218                                 if (t)
 219                                         *pid = t;
 220
 221                                 l = k;
 222                                 break;
 223                         }
 224
 225                         if (k == 0)
 226                                 break;
 227
 228                         k--;
 229                 }
 230         }
 231
 232         t = strndup(p, l);
 233         if (t)
 234                 *identifier = t;
 235
 236         e += strspn(p + e, WHITESPACE);
 237         *buf = p + e;
 238         return e;
 239 }
 240
 241 void syslog_parse_priority(const char **p, int *priority, bool with_facility) {
 242         int a = 0, b = 0, c = 0;
 243         int k;
 244
 245         assert(p);
 246         assert(*p);
 247         assert(priority);
 248
 249         if ((*p)[0] != '<')
 250                 return;
 251
 252         if (!strchr(*p, '>'))
 253                 return;
 254
 255         if ((*p)[2] == '>') {
 256                 c = undecchar((*p)[1]);
 257                 k = 3;
 258         } else if ((*p)[3] == '>') {
 259                 b = undecchar((*p)[1]);
 260                 c = undecchar((*p)[2]);
 261                 k = 4;
 262         } else if ((*p)[4] == '>') {
 263                 a = undecchar((*p)[1]);
 264                 b = undecchar((*p)[2]);
 265                 c = undecchar((*p)[3]);
 266                 k = 5;
 267         } else
 268                 return;
 269
 270         if (a < 0 || b < 0 || c < 0 ||
 271             (!with_facility && (a || b || c > 7)))
 272                 return;
 273
 274         if (with_facility)
 275                 *priority = a*100 + b*10 + c;
 276         else
 277                 *priority = (*priority & LOG_FACMASK) | c;
 278         *p += k;
 279 }
 280
 281 static void syslog_skip_date(char **buf) {
 282         enum {
 283                 LETTER,
 284                 SPACE,
 285                 NUMBER,
 286                 SPACE_OR_NUMBER,
 287                 COLON
 288         } sequence[] = {
 289                 LETTER, LETTER, LETTER,
 290                 SPACE,
 291                 SPACE_OR_NUMBER, NUMBER,
 292                 SPACE,
 293                 SPACE_OR_NUMBER, NUMBER,
 294                 COLON,
 295                 SPACE_OR_NUMBER, NUMBER,
 296                 COLON,
 297                 SPACE_OR_NUMBER, NUMBER,
 298                 SPACE
 299         };
 300
 301         char *p;
 302         unsigned i;
 303
 304         assert(buf);
 305         assert(*buf);
 306
 307         p = *buf;
 308
 309         for (i = 0; i < ELEMENTSOF(sequence); i++, p++) {
 310
 311                 if (!*p)
 312                         return;
 313
 314                 switch (sequence[i]) {
 315
 316                 case SPACE:
 317                         if (*p != ' ')
 318                                 return;
 319                         break;
 320
 321                 case SPACE_OR_NUMBER:
 322                         if (*p == ' ')
 323                                 break;
 324
 325                         /* fall through */
 326
 327                 case NUMBER:
 328                         if (*p < '0' || *p > '9')
 329                                 return;
 330
 331                         break;
 332
 333                 case LETTER:
 334                         if (!(*p >= 'A' && *p <= 'Z') &&
 335                             !(*p >= 'a' && *p <= 'z'))
 336                                 return;
 337
 338                         break;
 339
 340                 case COLON:
 341                         if (*p != ':')
 342                                 return;
 343                         break;
 344
 345                 }
 346         }
 347
 348         *buf = p;
 349 }
 350
 351 void server_process_syslog_message(
 352         Server *s,
 353         const char *buf,
 354         const struct ucred *ucred,
 355         const struct timeval *tv,
 356         const char *label,
 357         size_t label_len) {
 358
 359         char syslog_priority[sizeof("PRIORITY=") + DECIMAL_STR_MAX(int)],
 360              syslog_facility[sizeof("SYSLOG_FACILITY") + DECIMAL_STR_MAX(int)];
 361         const char *message = NULL, *syslog_identifier = NULL, *syslog_pid = NULL;
 362         struct iovec iovec[N_IOVEC_META_FIELDS + 6];
 363         unsigned n = 0;
 364         int priority = LOG_USER | LOG_INFO;
 365         _cleanup_free_ char *identifier = NULL, *pid = NULL;
 366         const char *orig;
 367
 368         assert(s);
 369         assert(buf);
 370
 371         orig = buf;
 372         syslog_parse_priority(&buf, &priority, true);
 373
 374         if (s->forward_to_syslog)
 375                 forward_syslog_raw(s, priority, orig, ucred, tv);
 376
 377         syslog_skip_date((char**) &buf);
 378         syslog_parse_identifier(&buf, &identifier, &pid);
 379
 380         if (s->forward_to_kmsg)
 381                 server_forward_kmsg(s, priority, identifier, buf, ucred);
 382
 383         if (s->forward_to_console)
 384                 server_forward_console(s, priority, identifier, buf, ucred);
 385
 386         if (s->forward_to_wall)
 387                 server_forward_wall(s, priority, identifier, buf, ucred);
 388
 389         IOVEC_SET_STRING(iovec[n++], "_TRANSPORT=syslog");
 390
 391         sprintf(syslog_priority, "PRIORITY=%i", priority & LOG_PRIMASK);
 392         IOVEC_SET_STRING(iovec[n++], syslog_priority);
 393
 394         if (priority & LOG_FACMASK) {
 395                 sprintf(syslog_facility, "SYSLOG_FACILITY=%i", LOG_FAC(priority));
 396                 IOVEC_SET_STRING(iovec[n++], syslog_facility);
 397         }
 398
 399         if (identifier) {
 400                 syslog_identifier = strappenda("SYSLOG_IDENTIFIER=", identifier);
 401                 if (syslog_identifier)
 402                         IOVEC_SET_STRING(iovec[n++], syslog_identifier);
 403         }
 404
 405         if (pid) {
 406                 syslog_pid = strappenda("SYSLOG_PID=", pid);
 407                 if (syslog_pid)
 408                         IOVEC_SET_STRING(iovec[n++], syslog_pid);
 409         }
 410
 411         message = strappenda("MESSAGE=", buf);
 412         if (message)
 413                 IOVEC_SET_STRING(iovec[n++], message);
 414
 415         server_dispatch_message(s, iovec, n, ELEMENTSOF(iovec), ucred, tv, label, label_len, NULL, priority, 0);
 416 }
 417
 418 int server_open_syslog_socket(Server *s) {
 419         static const int one = 1;
 420         int r;
 421
 422         assert(s);
 423
 424         if (s->syslog_fd < 0) {
 425                 static const union sockaddr_union sa = {
 426                         .un.sun_family = AF_UNIX,
 427                         .un.sun_path = "/run/systemd/journal/dev-log",
 428                 };
 429
 430                 s->syslog_fd = socket(AF_UNIX, SOCK_DGRAM|SOCK_CLOEXEC|SOCK_NONBLOCK, 0);
 431                 if (s->syslog_fd < 0)
 432                         return log_error_errno(errno, "socket() failed: %m");
 433
 434                 unlink(sa.un.sun_path);
 435
 436                 r = bind(s->syslog_fd, &sa.sa, offsetof(union sockaddr_union, un.sun_path) + strlen(sa.un.sun_path));
 437                 if (r < 0)
 438                         return log_error_errno(errno, "bind(%s) failed: %m", sa.un.sun_path);
 439
 440                 chmod(sa.un.sun_path, 0666);
 441         } else
 442                 fd_nonblock(s->syslog_fd, 1);
 443
 444         r = setsockopt(s->syslog_fd, SOL_SOCKET, SO_PASSCRED, &one, sizeof(one));
 445         if (r < 0)
 446                 return log_error_errno(errno, "SO_PASSCRED failed: %m");
 447
 448 #ifdef HAVE_SELINUX
 449         if (mac_selinux_use()) {
 450                 r = setsockopt(s->syslog_fd, SOL_SOCKET, SO_PASSSEC, &one, sizeof(one));
 451                 if (r < 0)
 452                         log_warning_errno(errno, "SO_PASSSEC failed: %m");
 453         }
 454 #endif
 455
 456         r = setsockopt(s->syslog_fd, SOL_SOCKET, SO_TIMESTAMP, &one, sizeof(one));
 457         if (r < 0)
 458                 return log_error_errno(errno, "SO_TIMESTAMP failed: %m");
 459
 460         r = sd_event_add_io(s->event, &s->syslog_event_source, s->syslog_fd, EPOLLIN, server_process_datagram, s);
 461         if (r < 0)
 462                 return log_error_errno(r, "Failed to add syslog server fd to event loop: %m");
 463
 464         return 0;
 465 }
 466
 467 void server_maybe_warn_forward_syslog_missed(Server *s) {
 468         usec_t n;
 469         assert(s);
 470
 471         if (s->n_forward_syslog_missed <= 0)
 472                 return;
 473
 474         n = now(CLOCK_MONOTONIC);
 475         if (s->last_warn_forward_syslog_missed + WARN_FORWARD_SYSLOG_MISSED_USEC > n)
 476                 return;
 477
 478         server_driver_message(s, SD_MESSAGE_FORWARD_SYSLOG_MISSED, "Forwarding to syslog missed %u messages.", s->n_forward_syslog_missed);
 479
 480         s->n_forward_syslog_missed = 0;
 481         s->last_warn_forward_syslog_missed = n;
 482 }