src/journal/journald-syslog.c

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