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[4], header_time[64],
 128              header_pid[sizeof("[]: ")-1 + DECIMAL_STR_MAX(pid_t) + 1];
 129         int n = 0;
 130         time_t t;
 131         struct tm *tm;
 132         char *ident_buf = NULL;
 133
 134         assert(s);
 135         assert(priority >= 0);
 136         assert(priority <= 999);
 137         assert(message);
 138
 139         if (LOG_PRI(priority) > s->max_level_syslog)
 140                 return;
 141
 142         /* First: priority field */
 143         xsprintf(header_priority, "<%i>", 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                 xsprintf(header_pid, "["PID_FMT"]: ", ucred->pid);
 163
 164                 if (identifier)
 165                         IOVEC_SET_STRING(iovec[n++], identifier);
 166
 167                 IOVEC_SET_STRING(iovec[n++], header_pid);
 168         } else if (identifier) {
 169                 IOVEC_SET_STRING(iovec[n++], identifier);
 170                 IOVEC_SET_STRING(iovec[n++], ": ");
 171         }
 172
 173         /* Fourth: message */
 174         IOVEC_SET_STRING(iovec[n++], message);
 175
 176         forward_syslog_iovec(s, iovec, n, ucred, tv);
 177
 178         free(ident_buf);
 179 }
 180
 181 int syslog_fixup_facility(int priority) {
 182
 183         if ((priority & LOG_FACMASK) == 0)
 184                 return (priority & LOG_PRIMASK) | LOG_USER;
 185
 186         return priority;
 187 }
 188
 189 size_t syslog_parse_identifier(const char **buf, char **identifier, char **pid) {
 190         const char *p;
 191         char *t;
 192         size_t l, e;
 193
 194         assert(buf);
 195         assert(identifier);
 196         assert(pid);
 197
 198         p = *buf;
 199
 200         p += strspn(p, WHITESPACE);
 201         l = strcspn(p, WHITESPACE);
 202
 203         if (l <= 0 ||
 204             p[l-1] != ':')
 205                 return 0;
 206
 207         e = l;
 208         l--;
 209
 210         if (p[l-1] == ']') {
 211                 size_t k = l-1;
 212
 213                 for (;;) {
 214
 215                         if (p[k] == '[') {
 216                                 t = strndup(p+k+1, l-k-2);
 217                                 if (t)
 218                                         *pid = t;
 219
 220                                 l = k;
 221                                 break;
 222                         }
 223
 224                         if (k == 0)
 225                                 break;
 226
 227                         k--;
 228                 }
 229         }
 230
 231         t = strndup(p, l);
 232         if (t)
 233                 *identifier = t;
 234
 235         e += strspn(p + e, WHITESPACE);
 236         *buf = p + e;
 237         return e;
 238 }
 239
 240 static void syslog_skip_date(char **buf) {
 241         enum {
 242                 LETTER,
 243                 SPACE,
 244                 NUMBER,
 245                 SPACE_OR_NUMBER,
 246                 COLON
 247         } sequence[] = {
 248                 LETTER, LETTER, LETTER,
 249                 SPACE,
 250                 SPACE_OR_NUMBER, NUMBER,
 251                 SPACE,
 252                 SPACE_OR_NUMBER, NUMBER,
 253                 COLON,
 254                 SPACE_OR_NUMBER, NUMBER,
 255                 COLON,
 256                 SPACE_OR_NUMBER, NUMBER,
 257                 SPACE
 258         };
 259
 260         char *p;
 261         unsigned i;
 262
 263         assert(buf);
 264         assert(*buf);
 265
 266         p = *buf;
 267
 268         for (i = 0; i < ELEMENTSOF(sequence); i++, p++) {
 269
 270                 if (!*p)
 271                         return;
 272
 273                 switch (sequence[i]) {
 274
 275                 case SPACE:
 276                         if (*p != ' ')
 277                                 return;
 278                         break;
 279
 280                 case SPACE_OR_NUMBER:
 281                         if (*p == ' ')
 282                                 break;
 283
 284                         /* fall through */
 285
 286                 case NUMBER:
 287                         if (*p < '0' || *p > '9')
 288                                 return;
 289
 290                         break;
 291
 292                 case LETTER:
 293                         if (!(*p >= 'A' && *p <= 'Z') &&
 294                             !(*p >= 'a' && *p <= 'z'))
 295                                 return;
 296
 297                         break;
 298
 299                 case COLON:
 300                         if (*p != ':')
 301                                 return;
 302                         break;
 303
 304                 }
 305         }
 306
 307         *buf = p;
 308 }
 309
 310 void server_process_syslog_message(
 311         Server *s,
 312         const char *buf,
 313         const struct ucred *ucred,
 314         const struct timeval *tv,
 315         const char *label,
 316         size_t label_len) {
 317
 318         char syslog_priority[sizeof("PRIORITY=") + DECIMAL_STR_MAX(int)],
 319              syslog_facility[sizeof("SYSLOG_FACILITY") + DECIMAL_STR_MAX(int)];
 320         const char *message = NULL, *syslog_identifier = NULL, *syslog_pid = NULL;
 321         struct iovec iovec[N_IOVEC_META_FIELDS + 6];
 322         unsigned n = 0;
 323         int priority = LOG_USER | LOG_INFO;
 324         _cleanup_free_ char *identifier = NULL, *pid = NULL;
 325         const char *orig;
 326
 327         assert(s);
 328         assert(buf);
 329
 330         orig = buf;
 331         syslog_parse_priority(&buf, &priority, true);
 332
 333         if (s->forward_to_syslog)
 334                 forward_syslog_raw(s, priority, orig, ucred, tv);
 335
 336         syslog_skip_date((char**) &buf);
 337         syslog_parse_identifier(&buf, &identifier, &pid);
 338
 339         if (s->forward_to_kmsg)
 340                 server_forward_kmsg(s, priority, identifier, buf, ucred);
 341
 342         if (s->forward_to_console)
 343                 server_forward_console(s, priority, identifier, buf, ucred);
 344
 345         if (s->forward_to_wall)
 346                 server_forward_wall(s, priority, identifier, buf, ucred);
 347
 348         IOVEC_SET_STRING(iovec[n++], "_TRANSPORT=syslog");
 349
 350         sprintf(syslog_priority, "PRIORITY=%i", priority & LOG_PRIMASK);
 351         IOVEC_SET_STRING(iovec[n++], syslog_priority);
 352
 353         if (priority & LOG_FACMASK) {
 354                 sprintf(syslog_facility, "SYSLOG_FACILITY=%i", LOG_FAC(priority));
 355                 IOVEC_SET_STRING(iovec[n++], syslog_facility);
 356         }
 357
 358         if (identifier) {
 359                 syslog_identifier = strjoina("SYSLOG_IDENTIFIER=", identifier);
 360                 if (syslog_identifier)
 361                         IOVEC_SET_STRING(iovec[n++], syslog_identifier);
 362         }
 363
 364         if (pid) {
 365                 syslog_pid = strjoina("SYSLOG_PID=", pid);
 366                 if (syslog_pid)
 367                         IOVEC_SET_STRING(iovec[n++], syslog_pid);
 368         }
 369
 370         message = strjoina("MESSAGE=", buf);
 371         if (message)
 372                 IOVEC_SET_STRING(iovec[n++], message);
 373
 374         server_dispatch_message(s, iovec, n, ELEMENTSOF(iovec), ucred, tv, label, label_len, NULL, priority, 0);
 375 }
 376
 377 int server_open_syslog_socket(Server *s) {
 378         static const int one = 1;
 379         int r;
 380
 381         assert(s);
 382
 383         if (s->syslog_fd < 0) {
 384                 static const union sockaddr_union sa = {
 385                         .un.sun_family = AF_UNIX,
 386                         .un.sun_path = "/run/systemd/journal/dev-log",
 387                 };
 388
 389                 s->syslog_fd = socket(AF_UNIX, SOCK_DGRAM|SOCK_CLOEXEC|SOCK_NONBLOCK, 0);
 390                 if (s->syslog_fd < 0)
 391                         return log_error_errno(errno, "socket() failed: %m");
 392
 393                 unlink(sa.un.sun_path);
 394
 395                 r = bind(s->syslog_fd, &sa.sa, offsetof(union sockaddr_union, un.sun_path) + strlen(sa.un.sun_path));
 396                 if (r < 0)
 397                         return log_error_errno(errno, "bind(%s) failed: %m", sa.un.sun_path);
 398
 399                 chmod(sa.un.sun_path, 0666);
 400         } else
 401                 fd_nonblock(s->syslog_fd, 1);
 402
 403         r = setsockopt(s->syslog_fd, SOL_SOCKET, SO_PASSCRED, &one, sizeof(one));
 404         if (r < 0)
 405                 return log_error_errno(errno, "SO_PASSCRED failed: %m");
 406
 407 #ifdef HAVE_SELINUX
 408         if (mac_selinux_use()) {
 409                 r = setsockopt(s->syslog_fd, SOL_SOCKET, SO_PASSSEC, &one, sizeof(one));
 410                 if (r < 0)
 411                         log_warning_errno(errno, "SO_PASSSEC failed: %m");
 412         }
 413 #endif
 414
 415         r = setsockopt(s->syslog_fd, SOL_SOCKET, SO_TIMESTAMP, &one, sizeof(one));
 416         if (r < 0)
 417                 return log_error_errno(errno, "SO_TIMESTAMP failed: %m");
 418
 419         r = sd_event_add_io(s->event, &s->syslog_event_source, s->syslog_fd, EPOLLIN, server_process_datagram, s);
 420         if (r < 0)
 421                 return log_error_errno(r, "Failed to add syslog server fd to event loop: %m");
 422
 423         return 0;
 424 }
 425
 426 void server_maybe_warn_forward_syslog_missed(Server *s) {
 427         usec_t n;
 428         assert(s);
 429
 430         if (s->n_forward_syslog_missed <= 0)
 431                 return;
 432
 433         n = now(CLOCK_MONOTONIC);
 434         if (s->last_warn_forward_syslog_missed + WARN_FORWARD_SYSLOG_MISSED_USEC > n)
 435                 return;
 436
 437         server_driver_message(s, SD_MESSAGE_FORWARD_SYSLOG_MISSED, "Forwarding to syslog missed %u messages.", s->n_forward_syslog_missed);
 438
 439         s->n_forward_syslog_missed = 0;
 440         s->last_warn_forward_syslog_missed = n;
 441 }