src/libsystemd/sd-journal/journal-send.c

   1 /* SPDX-License-Identifier: LGPL-2.1-or-later */
   2
   3 #include <errno.h>
   4 #include <fcntl.h>
   5 #include <printf.h>
   6 #include <stddef.h>
   7 #include <sys/un.h>
   8 #include <unistd.h>
   9 #if HAVE_VALGRIND_VALGRIND_H
  10 #include <valgrind/valgrind.h>
  11 #endif
  12
  13 #define SD_JOURNAL_SUPPRESS_LOCATION
  14
  15 #include "sd-journal.h"
  16
  17 #include "alloc-util.h"
  18 #include "errno-util.h"
  19 #include "fd-util.h"
  20 #include "fileio.h"
  21 #include "io-util.h"
  22 #include "journal-send.h"
  23 #include "memfd-util.h"
  24 #include "socket-util.h"
  25 #include "stdio-util.h"
  26 #include "string-util.h"
  27 #include "tmpfile-util.h"
  28
  29 #define SNDBUF_SIZE (8*1024*1024)
  30
  31 #define ALLOCA_CODE_FUNC(f, func)                 \
  32         do {                                      \
  33                 size_t _fl;                       \
  34                 const char *_func = (func);       \
  35                 char **_f = &(f);                 \
  36                 _fl = strlen(_func) + 1;          \
  37                 *_f = newa(char, _fl + 10);       \
  38                 memcpy(*_f, "CODE_FUNC=", 10);    \
  39                 memcpy(*_f + 10, _func, _fl);     \
  40         } while (false)
  41
  42 /* We open a single fd, and we'll share it with the current process,
  43  * all its threads, and all its subprocesses. This means we need to
  44  * initialize it atomically, and need to operate on it atomically
  45  * never assuming we are the only user */
  46 static int fd_plus_one = 0;
  47
  48 static int journal_fd(void) {
  49         int fd;
  50
  51 retry:
  52         if (fd_plus_one > 0)
  53                 return fd_plus_one - 1;
  54
  55         fd = socket(AF_UNIX, SOCK_DGRAM|SOCK_CLOEXEC, 0);
  56         if (fd < 0)
  57                 return -errno;
  58
  59         fd_inc_sndbuf(fd, SNDBUF_SIZE);
  60
  61         if (!__atomic_compare_exchange_n(&fd_plus_one, &(int){0}, fd+1,
  62                 false, __ATOMIC_SEQ_CST, __ATOMIC_SEQ_CST)) {
  63                 safe_close(fd);
  64                 goto retry;
  65         }
  66
  67         return fd;
  68 }
  69
  70 int journal_fd_nonblock(bool nonblock) {
  71         int r;
  72
  73         r = journal_fd();
  74         if (r < 0)
  75                 return r;
  76
  77         return fd_nonblock(r, nonblock);
  78 }
  79
  80 #if VALGRIND
  81 void close_journal_fd(void) {
  82         /* Be nice to valgrind. This is not atomic. This must be used only in tests. */
  83
  84         if (!RUNNING_ON_VALGRIND)
  85                 return;
  86
  87         if (getpid() != gettid())
  88                 return;
  89
  90         if (fd_plus_one <= 0)
  91                 return;
  92
  93         safe_close(fd_plus_one - 1);
  94         fd_plus_one = 0;
  95 }
  96 #endif
  97
  98 _public_ int sd_journal_print(int priority, const char *format, ...) {
  99         int r;
 100         va_list ap;
 101
 102         va_start(ap, format);
 103         r = sd_journal_printv(priority, format, ap);
 104         va_end(ap);
 105
 106         return r;
 107 }
 108
 109 _public_ int sd_journal_printv(int priority, const char *format, va_list ap) {
 110         char p[STRLEN("PRIORITY=") + DECIMAL_STR_MAX(int) + 1];
 111         char sbuf[LINE_MAX + 8] = "MESSAGE=";
 112         struct iovec iov[2];
 113         int len;
 114         va_list aq;
 115         char *buffer = sbuf;
 116
 117         assert_return(priority >= 0, -EINVAL);
 118         assert_return(priority <= 7, -EINVAL);
 119         assert_return(format, -EINVAL);
 120
 121         xsprintf(p, "PRIORITY=%i", priority & LOG_PRIMASK);
 122
 123         va_copy(aq, ap);
 124         len = vsnprintf(buffer + 8, LINE_MAX, format, aq);
 125         va_end(aq);
 126
 127         if (len >= (int)LONG_LINE_MAX - 8)
 128                 return -ENOBUFS;
 129
 130         /* Allocate large buffer to accommodate big message */
 131         if (len >= LINE_MAX) {
 132                 buffer = alloca_safe(len + 9);
 133                 memcpy(buffer, "MESSAGE=", 8);
 134                 assert_se(vsnprintf(buffer + 8, len + 1, format, ap) == len);
 135         }
 136
 137         /* Strip trailing whitespace, keep prefix whitespace. */
 138         (void) strstrip(buffer);
 139
 140         /* Suppress empty lines */
 141         if (isempty(buffer + 8))
 142                 return 0;
 143
 144         iov[0] = IOVEC_MAKE_STRING(buffer);
 145         iov[1] = IOVEC_MAKE_STRING(p);
 146
 147         return sd_journal_sendv(iov, 2);
 148 }
 149
 150 _printf_(1, 0) static int fill_iovec_sprintf(const char *format, va_list ap, int extra, struct iovec **_iov) {
 151         PROTECT_ERRNO;
 152         int r, n = 0, i = 0, j;
 153         struct iovec *iov = NULL;
 154
 155         assert(_iov);
 156
 157         if (extra > 0) {
 158                 n = MAX(extra * 2, extra + 4);
 159                 iov = malloc0(n * sizeof(struct iovec));
 160                 if (!iov) {
 161                         r = -ENOMEM;
 162                         goto fail;
 163                 }
 164
 165                 i = extra;
 166         }
 167
 168         while (format) {
 169                 struct iovec *c;
 170                 char *buffer;
 171                 va_list aq;
 172
 173                 if (i >= n) {
 174                         n = MAX(i*2, 4);
 175                         c = reallocarray(iov, n, sizeof(struct iovec));
 176                         if (!c) {
 177                                 r = -ENOMEM;
 178                                 goto fail;
 179                         }
 180
 181                         iov = c;
 182                 }
 183
 184                 va_copy(aq, ap);
 185                 if (vasprintf(&buffer, format, aq) < 0) {
 186                         va_end(aq);
 187                         r = -ENOMEM;
 188                         goto fail;
 189                 }
 190                 va_end(aq);
 191
 192                 VA_FORMAT_ADVANCE(format, ap);
 193
 194                 (void) strstrip(buffer); /* strip trailing whitespace, keep prefixing whitespace */
 195
 196                 iov[i++] = IOVEC_MAKE_STRING(buffer);
 197
 198                 format = va_arg(ap, char *);
 199         }
 200
 201         *_iov = iov;
 202
 203         return i;
 204
 205 fail:
 206         for (j = 0; j < i; j++)
 207                 free(iov[j].iov_base);
 208
 209         free(iov);
 210
 211         return r;
 212 }
 213
 214 _public_ int sd_journal_send(const char *format, ...) {
 215         int r, i, j;
 216         va_list ap;
 217         struct iovec *iov = NULL;
 218
 219         va_start(ap, format);
 220         i = fill_iovec_sprintf(format, ap, 0, &iov);
 221         va_end(ap);
 222
 223         if (_unlikely_(i < 0)) {
 224                 r = i;
 225                 goto finish;
 226         }
 227
 228         r = sd_journal_sendv(iov, i);
 229
 230 finish:
 231         for (j = 0; j < i; j++)
 232                 free(iov[j].iov_base);
 233
 234         free(iov);
 235
 236         return r;
 237 }
 238
 239 _public_ int sd_journal_sendv(const struct iovec *iov, int n) {
 240         PROTECT_ERRNO;
 241         int fd, r;
 242         _cleanup_close_ int buffer_fd = -EBADF;
 243         struct iovec *w;
 244         uint64_t *l;
 245         int i, j = 0;
 246         static const union sockaddr_union sa = {
 247                 .un.sun_family = AF_UNIX,
 248                 .un.sun_path = "/run/systemd/journal/socket",
 249         };
 250         struct msghdr mh = {
 251                 .msg_name = (struct sockaddr*) &sa.sa,
 252                 .msg_namelen = SOCKADDR_UN_LEN(sa.un),
 253         };
 254         ssize_t k;
 255         bool have_syslog_identifier = false;
 256         bool seal = true;
 257
 258         assert_return(iov, -EINVAL);
 259         assert_return(n > 0, -EINVAL);
 260
 261         w = newa(struct iovec, n * 5 + 3);
 262         l = newa(uint64_t, n);
 263
 264         for (i = 0; i < n; i++) {
 265                 char *c, *nl;
 266
 267                 if (_unlikely_(!iov[i].iov_base || iov[i].iov_len <= 1))
 268                         return -EINVAL;
 269
 270                 c = memchr(iov[i].iov_base, '=', iov[i].iov_len);
 271                 if (_unlikely_(!c || c == iov[i].iov_base))
 272                         return -EINVAL;
 273
 274                 have_syslog_identifier = have_syslog_identifier ||
 275                         (c == (char *) iov[i].iov_base + 17 &&
 276                          startswith(iov[i].iov_base, "SYSLOG_IDENTIFIER"));
 277
 278                 nl = memchr(iov[i].iov_base, '\n', iov[i].iov_len);
 279                 if (nl) {
 280                         if (_unlikely_(nl < c))
 281                                 return -EINVAL;
 282
 283                         /* Already includes a newline? Bummer, then
 284                          * let's write the variable name, then a
 285                          * newline, then the size (64bit LE), followed
 286                          * by the data and a final newline */
 287
 288                         w[j++] = IOVEC_MAKE(iov[i].iov_base, c - (char*) iov[i].iov_base);
 289                         w[j++] = IOVEC_MAKE_STRING("\n");
 290
 291                         l[i] = htole64(iov[i].iov_len - (c - (char*) iov[i].iov_base) - 1);
 292                         w[j++] = IOVEC_MAKE(&l[i], sizeof(uint64_t));
 293
 294                         w[j++] = IOVEC_MAKE(c + 1, iov[i].iov_len - (c - (char*) iov[i].iov_base) - 1);
 295                 } else
 296                         /* Nothing special? Then just add the line and
 297                          * append a newline */
 298                         w[j++] = iov[i];
 299
 300                 w[j++] = IOVEC_MAKE_STRING("\n");
 301         }
 302
 303         if (!have_syslog_identifier &&
 304             string_is_safe(program_invocation_short_name)) {
 305
 306                 /* Implicitly add program_invocation_short_name, if it
 307                  * is not set explicitly. We only do this for
 308                  * program_invocation_short_name, and nothing else
 309                  * since everything else is much nicer to retrieve
 310                  * from the outside. */
 311
 312                 w[j++] = IOVEC_MAKE_STRING("SYSLOG_IDENTIFIER=");
 313                 w[j++] = IOVEC_MAKE_STRING(program_invocation_short_name);
 314                 w[j++] = IOVEC_MAKE_STRING("\n");
 315         }
 316
 317         fd = journal_fd();
 318         if (_unlikely_(fd < 0))
 319                 return fd;
 320
 321         mh.msg_iov = w;
 322         mh.msg_iovlen = j;
 323
 324         k = sendmsg(fd, &mh, MSG_NOSIGNAL);
 325         if (k >= 0)
 326                 return 0;
 327
 328         /* Fail silently if the journal is not available */
 329         if (errno == ENOENT)
 330                 return 0;
 331
 332         if (!IN_SET(errno, EMSGSIZE, ENOBUFS, EAGAIN))
 333                 return -errno;
 334
 335         /* Message doesn't fit... Let's dump the data in a memfd or
 336          * temporary file and just pass a file descriptor of it to the
 337          * other side.
 338          *
 339          * For the temporary files we use /dev/shm instead of /tmp
 340          * here, since we want this to be a tmpfs, and one that is
 341          * available from early boot on and where unprivileged users
 342          * can create files. */
 343         buffer_fd = memfd_new(NULL);
 344         if (buffer_fd < 0) {
 345                 if (buffer_fd == -ENOSYS) {
 346                         buffer_fd = open_tmpfile_unlinkable("/dev/shm", O_RDWR | O_CLOEXEC);
 347                         if (buffer_fd < 0)
 348                                 return buffer_fd;
 349
 350                         seal = false;
 351                 } else
 352                         return buffer_fd;
 353         }
 354
 355         n = writev(buffer_fd, w, j);
 356         if (n < 0)
 357                 return -errno;
 358
 359         if (seal) {
 360                 r = memfd_set_sealed(buffer_fd);
 361                 if (r < 0)
 362                         return r;
 363         }
 364
 365         r = send_one_fd_sa(fd, buffer_fd, mh.msg_name, mh.msg_namelen, 0);
 366         if (r == -ENOENT)
 367                 /* Fail silently if the journal is not available */
 368                 return 0;
 369         return r;
 370 }
 371
 372 static int fill_iovec_perror_and_send(const char *message, int skip, struct iovec iov[]) {
 373         PROTECT_ERRNO;
 374         size_t n, k;
 375
 376         k = isempty(message) ? 0 : strlen(message) + 2;
 377         n = 8 + k + 256 + 1;
 378
 379         for (;;) {
 380                 char buffer[n];
 381                 char* j;
 382
 383                 errno = 0;
 384                 j = strerror_r(_saved_errno_, buffer + 8 + k, n - 8 - k);
 385                 if (errno == 0) {
 386                         char error[STRLEN("ERRNO=") + DECIMAL_STR_MAX(int) + 1];
 387
 388                         if (j != buffer + 8 + k)
 389                                 memmove(buffer + 8 + k, j, strlen(j)+1);
 390
 391                         memcpy(buffer, "MESSAGE=", 8);
 392
 393                         if (k > 0) {
 394                                 memcpy(buffer + 8, message, k - 2);
 395                                 memcpy(buffer + 8 + k - 2, ": ", 2);
 396                         }
 397
 398                         xsprintf(error, "ERRNO=%i", _saved_errno_);
 399
 400                         assert_cc(3 == LOG_ERR);
 401                         iov[skip+0] = IOVEC_MAKE_STRING("PRIORITY=3");
 402                         iov[skip+1] = IOVEC_MAKE_STRING(buffer);
 403                         iov[skip+2] = IOVEC_MAKE_STRING(error);
 404
 405                         return sd_journal_sendv(iov, skip + 3);
 406                 }
 407
 408                 if (errno != ERANGE)
 409                         return -errno;
 410
 411                 n *= 2;
 412         }
 413 }
 414
 415 _public_ int sd_journal_perror(const char *message) {
 416         struct iovec iovec[3];
 417
 418         return fill_iovec_perror_and_send(message, 0, iovec);
 419 }
 420
 421 _public_ int sd_journal_stream_fd(const char *identifier, int priority, int level_prefix) {
 422         _cleanup_close_ int fd = -EBADF;
 423         char *header;
 424         size_t l;
 425         int r;
 426
 427         assert_return(priority >= 0, -EINVAL);
 428         assert_return(priority <= 7, -EINVAL);
 429
 430         fd = socket(AF_UNIX, SOCK_STREAM|SOCK_CLOEXEC, 0);
 431         if (fd < 0)
 432                 return -errno;
 433
 434         r = connect_unix_path(fd, AT_FDCWD, "/run/systemd/journal/stdout");
 435         if (r < 0)
 436                 return r;
 437
 438         if (shutdown(fd, SHUT_RD) < 0)
 439                 return -errno;
 440
 441         (void) fd_inc_sndbuf(fd, SNDBUF_SIZE);
 442
 443         identifier = strempty(identifier);
 444
 445         l = strlen(identifier);
 446         header = newa(char, l + 1 + 1 + 2 + 2 + 2 + 2 + 2);
 447
 448         memcpy(header, identifier, l);
 449         header[l++] = '\n';
 450         header[l++] = '\n'; /* unit id */
 451         header[l++] = '0' + priority;
 452         header[l++] = '\n';
 453         header[l++] = '0' + !!level_prefix;
 454         header[l++] = '\n';
 455         header[l++] = '0';
 456         header[l++] = '\n';
 457         header[l++] = '0';
 458         header[l++] = '\n';
 459         header[l++] = '0';
 460         header[l++] = '\n';
 461
 462         r = loop_write(fd, header, l, false);
 463         if (r < 0)
 464                 return r;
 465
 466         return TAKE_FD(fd);
 467 }
 468
 469 _public_ int sd_journal_print_with_location(int priority, const char *file, const char *line, const char *func, const char *format, ...) {
 470         int r;
 471         va_list ap;
 472
 473         va_start(ap, format);
 474         r = sd_journal_printv_with_location(priority, file, line, func, format, ap);
 475         va_end(ap);
 476
 477         return r;
 478 }
 479
 480 _public_ int sd_journal_printv_with_location(int priority, const char *file, const char *line, const char *func, const char *format, va_list ap) {
 481         char p[STRLEN("PRIORITY=") + DECIMAL_STR_MAX(int) + 1];
 482         char sbuf[LINE_MAX + 8] = "MESSAGE=";
 483         struct iovec iov[5];
 484         char *f;
 485         int len;
 486         char *buffer = sbuf;
 487         va_list aq;
 488
 489         assert_return(priority >= 0, -EINVAL);
 490         assert_return(priority <= 7, -EINVAL);
 491         assert_return(format, -EINVAL);
 492
 493         xsprintf(p, "PRIORITY=%i", priority & LOG_PRIMASK);
 494
 495         va_copy(aq, ap);
 496         len = vsnprintf(buffer + 8, LINE_MAX, format, aq);
 497         va_end(aq);
 498
 499         if (len >= (int)LONG_LINE_MAX - 8)
 500                 return -ENOBUFS;
 501
 502         /* Allocate large buffer to accommodate big message */
 503         if (len >= LINE_MAX) {
 504                 buffer = alloca_safe(len + 9);
 505                 memcpy(buffer, "MESSAGE=", 8);
 506                 assert_se(vsnprintf(buffer + 8, len + 1, format, ap) == len);
 507         }
 508
 509         /* Strip trailing whitespace, keep prefixing whitespace */
 510         (void) strstrip(buffer);
 511
 512         /* Suppress empty lines */
 513         if (isempty(buffer + 8))
 514                 return 0;
 515
 516         /* func is initialized from __func__ which is not a macro, but
 517          * a static const char[], hence cannot easily be prefixed with
 518          * CODE_FUNC=, hence let's do it manually here. */
 519         ALLOCA_CODE_FUNC(f, func);
 520
 521         iov[0] = IOVEC_MAKE_STRING(buffer);
 522         iov[1] = IOVEC_MAKE_STRING(p);
 523         iov[2] = IOVEC_MAKE_STRING(file);
 524         iov[3] = IOVEC_MAKE_STRING(line);
 525         iov[4] = IOVEC_MAKE_STRING(f);
 526
 527         return sd_journal_sendv(iov, ELEMENTSOF(iov));
 528 }
 529
 530 _public_ int sd_journal_send_with_location(const char *file, const char *line, const char *func, const char *format, ...) {
 531         _cleanup_free_ struct iovec *iov = NULL;
 532         int r, i, j;
 533         va_list ap;
 534         char *f;
 535
 536         va_start(ap, format);
 537         i = fill_iovec_sprintf(format, ap, 3, &iov);
 538         va_end(ap);
 539
 540         if (_unlikely_(i < 0)) {
 541                 r = i;
 542                 goto finish;
 543         }
 544
 545         ALLOCA_CODE_FUNC(f, func);
 546
 547         iov[0] = IOVEC_MAKE_STRING(file);
 548         iov[1] = IOVEC_MAKE_STRING(line);
 549         iov[2] = IOVEC_MAKE_STRING(f);
 550
 551         r = sd_journal_sendv(iov, i);
 552
 553 finish:
 554         for (j = 3; j < i; j++)
 555                 free(iov[j].iov_base);
 556
 557         return r;
 558 }
 559
 560 _public_ int sd_journal_sendv_with_location(
 561                 const char *file, const char *line,
 562                 const char *func,
 563                 const struct iovec *iov, int n) {
 564
 565         struct iovec *niov;
 566         char *f;
 567
 568         assert_return(iov, -EINVAL);
 569         assert_return(n > 0, -EINVAL);
 570
 571         niov = newa(struct iovec, n + 3);
 572         memcpy(niov, iov, sizeof(struct iovec) * n);
 573
 574         ALLOCA_CODE_FUNC(f, func);
 575
 576         niov[n++] = IOVEC_MAKE_STRING(file);
 577         niov[n++] = IOVEC_MAKE_STRING(line);
 578         niov[n++] = IOVEC_MAKE_STRING(f);
 579
 580         return sd_journal_sendv(niov, n);
 581 }
 582
 583 _public_ int sd_journal_perror_with_location(
 584                 const char *file, const char *line,
 585                 const char *func,
 586                 const char *message) {
 587
 588         struct iovec iov[6];
 589         char *f;
 590
 591         ALLOCA_CODE_FUNC(f, func);
 592
 593         iov[0] = IOVEC_MAKE_STRING(file);
 594         iov[1] = IOVEC_MAKE_STRING(line);
 595         iov[2] = IOVEC_MAKE_STRING(f);
 596
 597         return fill_iovec_perror_and_send(message, 3, iov);
 598 }