1 /* 2 * CDDL HEADER START 3 * 4 * The contents of this file are subject to the terms of the 5 * Common Development and Distribution License (the "License"). 6 * You may not use this file except in compliance with the License. 7 * 8 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE 9 * or http://www.opensolaris.org/os/licensing. 10 * See the License for the specific language governing permissions 11 * and limitations under the License. 12 * 13 * When distributing Covered Code, include this CDDL HEADER in each 14 * file and include the License file at usr/src/OPENSOLARIS.LICENSE. 15 * If applicable, add the following below this CDDL HEADER, with the 16 * fields enclosed by brackets "[]" replaced with your own identifying 17 * information: Portions Copyright [yyyy] [name of copyright owner] 18 * 19 * CDDL HEADER END 20 */ 21 22 /* 23 * Copyright 2006 Sun Microsystems, Inc. All rights reserved. 24 * Use is subject to license terms. 25 */ 26 27 /* Copyright (c) 1988 AT&T */ 28 /* All Rights Reserved */ 29 30 /* 31 * University Copyright- Copyright (c) 1982, 1986, 1988 32 * The Regents of the University of California 33 * All Rights Reserved 34 * 35 * University Acknowledgment- Portions of this document are derived from 36 * software developed by the University of California, Berkeley, and its 37 * contributors. 38 */ 39 40 #pragma ident "%Z%%M% %I% %E% SMI" 41 42 /* 43 * SYSLOG -- print message on log file 44 * 45 * This routine looks a lot like printf, except that it 46 * outputs to the log file instead of the standard output. 47 * Also: 48 * adds a timestamp, 49 * prints the module name in front of the message, 50 * has some other formatting types (or will sometime), 51 * adds a newline on the end of the message. 52 * 53 * The output of this routine is intended to be read by /etc/syslogd. 54 */ 55 56 #pragma weak syslog = _syslog 57 #pragma weak vsyslog = _vsyslog 58 #pragma weak openlog = _openlog 59 #pragma weak closelog = _closelog 60 #pragma weak setlogmask = _setlogmask 61 62 #include "synonyms.h" 63 #include <sys/types.h> 64 #include <sys/types32.h> 65 #include <sys/mman.h> 66 #include <sys/stropts.h> 67 #include <sys/strlog.h> 68 #include <sys/log.h> /* for LOG_MAXPS */ 69 #include <stdlib.h> 70 #include <procfs.h> 71 #include <syslog.h> 72 #include <signal.h> 73 #include <fcntl.h> 74 #include <string.h> 75 #include <stdarg.h> 76 #include <unistd.h> 77 #include <wait.h> 78 #include <stdio.h> 79 #include <string.h> 80 #include <errno.h> 81 #include <thread.h> 82 #include <synch.h> 83 #include <sys/door.h> 84 #include <sys/stat.h> 85 #include <stropts.h> 86 #include <sys/fork.h> 87 #include <sys/wait.h> 88 #include "libc.h" 89 90 #define MAXLINE 1024 /* max message size (but see below) */ 91 92 #define PRIMASK(p) (1 << ((p) & LOG_PRIMASK)) 93 #define PRIFAC(p) (((p) & LOG_FACMASK) >> 3) 94 #define IMPORTANT LOG_ERR 95 96 #ifndef FALSE 97 #define FALSE 0 98 #endif 99 100 #ifndef TRUE 101 #define TRUE 1 102 #endif 103 104 #define logname "/dev/conslog" 105 #define ctty "/dev/syscon" 106 #define sysmsg "/dev/sysmsg" 107 108 #define DOORFILE "/var/run/syslog_door" 109 110 static struct __syslog { 111 int _LogFile; 112 int _LogStat; 113 const char *_LogTag; 114 int _LogMask; 115 char *_SyslogHost; 116 int _LogFacility; 117 int _LogFileInvalid; 118 int _OpenLogCalled; 119 dev_t _LogDev; 120 char _ProcName[PRFNSZ + 1]; 121 } __syslog = { 122 -1, /* fd for log */ 123 0, /* status bits, set by openlog() */ 124 "syslog", /* string to tag the entry with */ 125 0xff, /* mask of priorities to be logged */ 126 NULL, 127 LOG_USER, /* default facility code */ 128 FALSE, /* check for validity of fd for log */ 129 0, /* openlog has not yet been called */ 130 }; 131 132 #define LogFile (__syslog._LogFile) 133 #define LogStat (__syslog._LogStat) 134 #define LogTag (__syslog._LogTag) 135 #define LogMask (__syslog._LogMask) 136 #define SyslogHost (__syslog._SyslogHost) 137 #define LogFacility (__syslog._LogFacility) 138 #define LogFileInvalid (__syslog._LogFileInvalid) 139 #define OpenLogCalled (__syslog._OpenLogCalled) 140 #define LogDev (__syslog._LogDev) 141 #define ProcName (__syslog._ProcName) 142 143 static int syslogd_ok(void); 144 145 /* 146 * Regrettably, there are several instances inside libc where 147 * syslog() is called from the bottom of a deep call stack 148 * and a critical lock was acquired near the top of the stack. 149 * 150 * Because syslog() uses stdio (and it is called from within stdio) 151 * it runs the danger of deadlocking, perhaps with an interposed 152 * malloc() when fork() is occurring concurrently, perhaps with 153 * some other lock within libc. 154 * 155 * The only fix for this problem is to restructure libc not to do 156 * this thing and always to call syslog() with no locks held. 157 * This restructuring will require a substantial effort. 158 * 159 * Meanwhile, we just hope that on the rare occasion that syslog() 160 * is called from within libc (such occurrences should "never happen") 161 * that we don't get caught in a race condition deadlock. 162 */ 163 void 164 syslog(int pri, const char *fmt, ...) 165 { 166 va_list ap; 167 168 va_start(ap, fmt); 169 vsyslog(pri, fmt, ap); 170 va_end(ap); 171 } 172 173 174 void 175 vsyslog(int pri, const char *fmt, va_list ap) 176 { 177 char *b, *f, *o; 178 char c; 179 int clen; 180 char buf[MAXLINE + 2]; 181 char outline[MAXLINE + 256]; /* pad to allow date, system name... */ 182 time_t now; 183 pid_t pid; 184 struct log_ctl hdr; 185 struct strbuf dat; 186 struct strbuf ctl; 187 char timestr[26]; /* hardwired value 26 due to Posix */ 188 size_t taglen; 189 int olderrno = errno; 190 struct stat statbuff; 191 int procfd; 192 char procfile[32]; 193 psinfo_t p; 194 int showpid; 195 uint32_t msgid; 196 char *msgid_start, *msgid_end; 197 int nowait; 198 199 /* 200 * Maximum tag length is 256 (the pad in outline) minus the size of the 201 * other things that can go in the pad. 202 */ 203 #define MAX_TAG 230 204 205 /* see if we should just throw out this message */ 206 if (pri < 0 || PRIFAC(pri) >= LOG_NFACILITIES || 207 (PRIMASK(pri) & LogMask) == 0) 208 return; 209 210 if (LogFileInvalid) 211 return; 212 213 /* 214 * if openlog() has not been called by the application, 215 * try to get the name of the application and set it 216 * as the ident string for messages. If unable to get 217 * it for any reason, fall back to using the default 218 * of syslog. If we succeed in getting the name, also 219 * turn on LOG_PID, to provide greater detail. 220 */ 221 showpid = 0; 222 if (OpenLogCalled == 0) { 223 (void) sprintf(procfile, "/proc/%d/psinfo", getpid()); 224 if ((procfd = open(procfile, O_RDONLY)) >= 0) { 225 if (read(procfd, &p, sizeof (psinfo_t)) >= 0) { 226 (void) strncpy(ProcName, p.pr_fname, PRFNSZ); 227 LogTag = (const char *) &ProcName; 228 showpid = LOG_PID; 229 } 230 (void) close(procfd); 231 } 232 } 233 if (LogFile < 0) 234 openlog(LogTag, LogStat|LOG_NDELAY|showpid, 0); 235 236 if ((fstat(LogFile, &statbuff) != 0) || 237 (!S_ISCHR(statbuff.st_mode)) || (statbuff.st_rdev != LogDev)) { 238 LogFileInvalid = TRUE; 239 return; 240 } 241 242 /* set default facility if none specified */ 243 if ((pri & LOG_FACMASK) == 0) 244 pri |= LogFacility; 245 246 /* build the header */ 247 hdr.pri = pri; 248 hdr.flags = SL_CONSOLE; 249 hdr.level = 0; 250 251 /* build the message */ 252 /* 253 * To avoid potential security problems, bounds checking is done 254 * on outline and buf. 255 * The following code presumes that the header information will 256 * fit in 250-odd bytes, as was accounted for in the buffer size 257 * allocation. This is dependent on the assumption that the LogTag 258 * and the string returned by sprintf() for getpid() will return 259 * be less than 230-odd characters combined. 260 */ 261 o = outline; 262 (void) time(&now); 263 (void) sprintf(o, "%.15s ", ctime_r(&now, timestr, 26) + 4); 264 o += strlen(o); 265 266 if (LogTag) { 267 taglen = strlen(LogTag) < MAX_TAG ? strlen(LogTag) : MAX_TAG; 268 (void) strncpy(o, LogTag, taglen); 269 o[taglen] = '\0'; 270 o += strlen(o); 271 } 272 if (LogStat & LOG_PID) { 273 (void) sprintf(o, "[%d]", getpid()); 274 o += strlen(o); 275 } 276 if (LogTag) { 277 (void) strcpy(o, ": "); 278 o += 2; 279 } 280 281 STRLOG_MAKE_MSGID(fmt, msgid); 282 (void) sprintf(o, "[ID %u FACILITY_AND_PRIORITY] ", msgid); 283 o += strlen(o); 284 285 b = buf; 286 f = (char *)fmt; 287 while ((c = *f++) != '\0' && b < &buf[MAXLINE]) { 288 char *errmsg; 289 if (c != '%') { 290 *b++ = c; 291 continue; 292 } 293 if ((c = *f++) != 'm') { 294 *b++ = '%'; 295 *b++ = c; 296 continue; 297 } 298 if ((errmsg = strerror(olderrno)) == NULL) 299 (void) snprintf(b, &buf[MAXLINE] - b, "error %d", 300 olderrno); 301 else { 302 while (*errmsg != '\0' && b < &buf[MAXLINE]) { 303 if (*errmsg == '%') { 304 (void) strcpy(b, "%%"); 305 b += 2; 306 } 307 else 308 *b++ = *errmsg; 309 errmsg++; 310 } 311 *b = '\0'; 312 } 313 b += strlen(b); 314 } 315 if (b > buf && *(b-1) != '\n') /* ensure at least one newline */ 316 *b++ = '\n'; 317 *b = '\0'; 318 /* LINTED variable format specifier */ 319 (void) vsnprintf(o, &outline[sizeof (outline)] - o, buf, ap); 320 clen = (int)strlen(outline) + 1; /* add one for NULL byte */ 321 if (clen > MAXLINE) { 322 clen = MAXLINE; 323 outline[MAXLINE-1] = '\0'; 324 } 325 326 /* 327 * 1136432 points out that the underlying log driver actually 328 * refuses to accept (ERANGE) messages longer than LOG_MAXPS 329 * bytes. So it really doesn't make much sense to putmsg a 330 * longer message.. 331 */ 332 if (clen > LOG_MAXPS) { 333 clen = LOG_MAXPS; 334 outline[LOG_MAXPS-1] = '\0'; 335 } 336 337 /* set up the strbufs */ 338 ctl.maxlen = sizeof (struct log_ctl); 339 ctl.len = sizeof (struct log_ctl); 340 ctl.buf = (caddr_t)&hdr; 341 dat.maxlen = sizeof (outline); 342 dat.len = clen; 343 dat.buf = outline; 344 345 /* output the message to the local logger */ 346 if ((putmsg(LogFile, &ctl, &dat, 0) >= 0) && syslogd_ok()) 347 return; 348 if (!(LogStat & LOG_CONS)) 349 return; 350 351 /* 352 * Output the message to the console directly. To reduce visual 353 * clutter, we strip out the message ID. 354 */ 355 if ((msgid_start = strstr(outline, "[ID ")) != NULL && 356 (msgid_end = strstr(msgid_start, "] ")) != NULL) 357 (void) strcpy(msgid_start, msgid_end + 2); 358 359 clen = strlen(outline) + 1; 360 361 nowait = (LogStat & LOG_NOWAIT); 362 pid = forkx(nowait? 0 : (FORK_NOSIGCHLD | FORK_WAITPID)); 363 if (pid == -1) 364 return; 365 366 if (pid == 0) { 367 sigset_t sigs; 368 int fd; 369 370 (void) sigset(SIGALRM, SIG_DFL); 371 (void) sigemptyset(&sigs); 372 (void) sigaddset(&sigs, SIGALRM); 373 (void) sigprocmask(SIG_UNBLOCK, &sigs, NULL); 374 (void) alarm(5); 375 if (((fd = open(sysmsg, O_WRONLY)) >= 0) || 376 (fd = open(ctty, O_WRONLY)) >= 0) { 377 (void) alarm(0); 378 outline[clen - 1] = '\r'; 379 (void) write(fd, outline, clen); 380 (void) close(fd); 381 } 382 _exit(0); 383 } 384 if (!nowait) 385 while (waitpid(pid, NULL, 0) == -1 && errno == EINTR) 386 continue; 387 } 388 389 /* 390 * Use a door call to syslogd to see if it's alive. 391 */ 392 static int 393 syslogd_ok(void) 394 { 395 int d; 396 int s; 397 door_arg_t darg; 398 door_info_t info; 399 400 if ((d = open(DOORFILE, O_RDONLY)) < 0) 401 return (0); 402 /* 403 * see if our pid matches the pid of the door server. 404 * If so, syslogd has called syslog(), probably as 405 * a result of some name service library error, and 406 * we don't want to let syslog continue and possibly 407 * fork here. 408 */ 409 info.di_target = 0; 410 if (__door_info(d, &info) < 0 || info.di_target == getpid()) { 411 (void) close(d); 412 return (0); 413 } 414 darg.data_ptr = NULL; 415 darg.data_size = 0; 416 darg.desc_ptr = NULL; 417 darg.desc_num = 0; 418 darg.rbuf = NULL; 419 darg.rsize = 0; 420 s = __door_call(d, &darg); 421 (void) close(d); 422 if (s < 0) 423 return (0); /* failure - syslogd dead */ 424 else 425 return (1); 426 } 427 428 /* 429 * OPENLOG -- open system log 430 */ 431 432 void 433 openlog(const char *ident, int logstat, int logfac) 434 { 435 struct stat statbuff; 436 437 OpenLogCalled = 1; 438 if (ident != NULL) 439 LogTag = ident; 440 LogStat = logstat; 441 if (logfac != 0) 442 LogFacility = logfac & LOG_FACMASK; 443 444 /* 445 * if the fstat(2) fails or the st_rdev has changed 446 * then we must open the file 447 */ 448 if ((fstat(LogFile, &statbuff) == 0) && 449 (S_ISCHR(statbuff.st_mode)) && (statbuff.st_rdev == LogDev)) 450 return; 451 452 if (LogStat & LOG_NDELAY) { 453 LogFile = open(logname, O_WRONLY); 454 (void) fcntl(LogFile, F_SETFD, 1); 455 (void) fstat(LogFile, &statbuff); 456 LogDev = statbuff.st_rdev; 457 } 458 } 459 460 /* 461 * CLOSELOG -- close the system log 462 */ 463 464 void 465 closelog(void) 466 { 467 struct stat statbuff; 468 469 OpenLogCalled = 0; 470 471 /* if the LogFile is invalid it can not be closed */ 472 if (LogFileInvalid) 473 return; 474 475 /* 476 * if the fstat(2) fails or the st_rdev has changed 477 * then we can not close the file 478 */ 479 if ((fstat(LogFile, &statbuff) == 0) && (statbuff.st_rdev == LogDev)) { 480 (void) close(LogFile); 481 LogFile = -1; 482 LogStat = 0; 483 } 484 } 485 486 /* 487 * SETLOGMASK -- set the log mask level 488 */ 489 int 490 setlogmask(int pmask) 491 { 492 int omask = 0; 493 494 omask = LogMask; 495 if (pmask != 0) 496 LogMask = pmask; 497 return (omask); 498 } 499