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 2008 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 58 #include "lint.h" 59 #include <sys/types.h> 60 #include <sys/types32.h> 61 #include <sys/mman.h> 62 #include <sys/stropts.h> 63 #include <sys/strlog.h> 64 #include <sys/log.h> /* for LOG_MAXPS */ 65 #include <stdlib.h> 66 #include <procfs.h> 67 #include <syslog.h> 68 #include <signal.h> 69 #include <fcntl.h> 70 #include <string.h> 71 #include <stdarg.h> 72 #include <unistd.h> 73 #include <wait.h> 74 #include <stdio.h> 75 #include <string.h> 76 #include <errno.h> 77 #include <thread.h> 78 #include <synch.h> 79 #include <sys/door.h> 80 #include <sys/stat.h> 81 #include <stropts.h> 82 #include <sys/fork.h> 83 #include <sys/wait.h> 84 #include "libc.h" 85 86 #define MAXLINE 1024 /* max message size (but see below) */ 87 88 #define PRIMASK(p) (1 << ((p) & LOG_PRIMASK)) 89 #define PRIFAC(p) (((p) & LOG_FACMASK) >> 3) 90 #define IMPORTANT LOG_ERR 91 92 #ifndef FALSE 93 #define FALSE 0 94 #endif 95 96 #ifndef TRUE 97 #define TRUE 1 98 #endif 99 100 #define logname "/dev/conslog" 101 #define ctty "/dev/syscon" 102 #define sysmsg "/dev/sysmsg" 103 104 #define DOORFILE "/var/run/syslog_door" 105 106 static struct __syslog { 107 int _LogFile; 108 int _LogStat; 109 const char *_LogTag; 110 int _LogMask; 111 char *_SyslogHost; 112 int _LogFacility; 113 int _LogFileInvalid; 114 int _OpenLogCalled; 115 dev_t _LogDev; 116 char _ProcName[PRFNSZ + 1]; 117 } __syslog = { 118 -1, /* fd for log */ 119 0, /* status bits, set by openlog() */ 120 "syslog", /* string to tag the entry with */ 121 0xff, /* mask of priorities to be logged */ 122 NULL, 123 LOG_USER, /* default facility code */ 124 FALSE, /* check for validity of fd for log */ 125 0, /* openlog has not yet been called */ 126 }; 127 128 #define LogFile (__syslog._LogFile) 129 #define LogStat (__syslog._LogStat) 130 #define LogTag (__syslog._LogTag) 131 #define LogMask (__syslog._LogMask) 132 #define SyslogHost (__syslog._SyslogHost) 133 #define LogFacility (__syslog._LogFacility) 134 #define LogFileInvalid (__syslog._LogFileInvalid) 135 #define OpenLogCalled (__syslog._OpenLogCalled) 136 #define LogDev (__syslog._LogDev) 137 #define ProcName (__syslog._ProcName) 138 139 static int syslogd_ok(void); 140 141 /* 142 * Regrettably, there are several instances inside libc where 143 * syslog() is called from the bottom of a deep call stack 144 * and a critical lock was acquired near the top of the stack. 145 * 146 * Because syslog() uses stdio (and it is called from within stdio) 147 * it runs the danger of deadlocking, perhaps with an interposed 148 * malloc() when fork() is occurring concurrently, perhaps with 149 * some other lock within libc. 150 * 151 * The only fix for this problem is to restructure libc not to do 152 * this thing and always to call syslog() with no locks held. 153 * This restructuring will require a substantial effort. 154 * 155 * Meanwhile, we just hope that on the rare occasion that syslog() 156 * is called from within libc (such occurrences should "never happen") 157 * that we don't get caught in a race condition deadlock. 158 */ 159 void 160 syslog(int pri, const char *fmt, ...) 161 { 162 va_list ap; 163 164 va_start(ap, fmt); 165 vsyslog(pri, fmt, ap); 166 va_end(ap); 167 } 168 169 170 void 171 vsyslog(int pri, const char *fmt, va_list ap) 172 { 173 char *b, *f, *o; 174 char c; 175 int clen; 176 char buf[MAXLINE + 2]; 177 char outline[MAXLINE + 256]; /* pad to allow date, system name... */ 178 time_t now; 179 pid_t pid; 180 struct log_ctl hdr; 181 struct strbuf dat; 182 struct strbuf ctl; 183 char timestr[26]; /* hardwired value 26 due to Posix */ 184 size_t taglen; 185 int olderrno = errno; 186 struct stat statbuff; 187 int procfd; 188 char procfile[32]; 189 psinfo_t p; 190 int showpid; 191 uint32_t msgid; 192 char *msgid_start, *msgid_end; 193 int nowait; 194 195 /* 196 * Maximum tag length is 256 (the pad in outline) minus the size of the 197 * other things that can go in the pad. 198 */ 199 #define MAX_TAG 230 200 201 /* see if we should just throw out this message */ 202 if (pri < 0 || PRIFAC(pri) >= LOG_NFACILITIES || 203 (PRIMASK(pri) & LogMask) == 0) 204 return; 205 206 if (LogFileInvalid) 207 return; 208 209 /* 210 * if openlog() has not been called by the application, 211 * try to get the name of the application and set it 212 * as the ident string for messages. If unable to get 213 * it for any reason, fall back to using the default 214 * of syslog. If we succeed in getting the name, also 215 * turn on LOG_PID, to provide greater detail. 216 */ 217 showpid = 0; 218 if (OpenLogCalled == 0) { 219 (void) sprintf(procfile, "/proc/%d/psinfo", getpid()); 220 if ((procfd = open(procfile, O_RDONLY)) >= 0) { 221 if (read(procfd, &p, sizeof (psinfo_t)) >= 0) { 222 (void) strncpy(ProcName, p.pr_fname, PRFNSZ); 223 LogTag = (const char *) &ProcName; 224 showpid = LOG_PID; 225 } 226 (void) close(procfd); 227 } 228 } 229 if (LogFile < 0) 230 openlog(LogTag, LogStat|LOG_NDELAY|showpid, 0); 231 232 if ((fstat(LogFile, &statbuff) != 0) || 233 (!S_ISCHR(statbuff.st_mode)) || (statbuff.st_rdev != LogDev)) { 234 LogFileInvalid = TRUE; 235 return; 236 } 237 238 /* set default facility if none specified */ 239 if ((pri & LOG_FACMASK) == 0) 240 pri |= LogFacility; 241 242 /* build the header */ 243 hdr.pri = pri; 244 hdr.flags = SL_CONSOLE; 245 hdr.level = 0; 246 247 /* build the message */ 248 /* 249 * To avoid potential security problems, bounds checking is done 250 * on outline and buf. 251 * The following code presumes that the header information will 252 * fit in 250-odd bytes, as was accounted for in the buffer size 253 * allocation. This is dependent on the assumption that the LogTag 254 * and the string returned by sprintf() for getpid() will return 255 * be less than 230-odd characters combined. 256 */ 257 o = outline; 258 (void) time(&now); 259 (void) sprintf(o, "%.15s ", ctime_r(&now, timestr, 26) + 4); 260 o += strlen(o); 261 262 if (LogTag) { 263 taglen = strlen(LogTag) < MAX_TAG ? strlen(LogTag) : MAX_TAG; 264 (void) strncpy(o, LogTag, taglen); 265 o[taglen] = '\0'; 266 o += strlen(o); 267 } 268 if (LogStat & LOG_PID) { 269 (void) sprintf(o, "[%d]", getpid()); 270 o += strlen(o); 271 } 272 if (LogTag) { 273 (void) strcpy(o, ": "); 274 o += 2; 275 } 276 277 STRLOG_MAKE_MSGID(fmt, msgid); 278 (void) sprintf(o, "[ID %u FACILITY_AND_PRIORITY] ", msgid); 279 o += strlen(o); 280 281 b = buf; 282 f = (char *)fmt; 283 while ((c = *f++) != '\0' && b < &buf[MAXLINE]) { 284 char *errmsg; 285 if (c != '%') { 286 *b++ = c; 287 continue; 288 } 289 if ((c = *f++) != 'm') { 290 *b++ = '%'; 291 *b++ = c; 292 continue; 293 } 294 if ((errmsg = strerror(olderrno)) == NULL) 295 (void) snprintf(b, &buf[MAXLINE] - b, "error %d", 296 olderrno); 297 else { 298 while (*errmsg != '\0' && b < &buf[MAXLINE]) { 299 if (*errmsg == '%') { 300 (void) strcpy(b, "%%"); 301 b += 2; 302 } 303 else 304 *b++ = *errmsg; 305 errmsg++; 306 } 307 *b = '\0'; 308 } 309 b += strlen(b); 310 } 311 if (b > buf && *(b-1) != '\n') /* ensure at least one newline */ 312 *b++ = '\n'; 313 *b = '\0'; 314 /* LINTED variable format specifier */ 315 (void) vsnprintf(o, &outline[sizeof (outline)] - o, buf, ap); 316 clen = (int)strlen(outline) + 1; /* add one for NULL byte */ 317 if (clen > MAXLINE) { 318 clen = MAXLINE; 319 outline[MAXLINE-1] = '\0'; 320 } 321 322 /* 323 * 1136432 points out that the underlying log driver actually 324 * refuses to accept (ERANGE) messages longer than LOG_MAXPS 325 * bytes. So it really doesn't make much sense to putmsg a 326 * longer message.. 327 */ 328 if (clen > LOG_MAXPS) { 329 clen = LOG_MAXPS; 330 outline[LOG_MAXPS-1] = '\0'; 331 } 332 333 /* set up the strbufs */ 334 ctl.maxlen = sizeof (struct log_ctl); 335 ctl.len = sizeof (struct log_ctl); 336 ctl.buf = (caddr_t)&hdr; 337 dat.maxlen = sizeof (outline); 338 dat.len = clen; 339 dat.buf = outline; 340 341 /* output the message to the local logger */ 342 if ((putmsg(LogFile, &ctl, &dat, 0) >= 0) && syslogd_ok()) 343 return; 344 if (!(LogStat & LOG_CONS)) 345 return; 346 347 /* 348 * Output the message to the console directly. To reduce visual 349 * clutter, we strip out the message ID. 350 */ 351 if ((msgid_start = strstr(outline, "[ID ")) != NULL && 352 (msgid_end = strstr(msgid_start, "] ")) != NULL) 353 (void) strcpy(msgid_start, msgid_end + 2); 354 355 clen = strlen(outline) + 1; 356 357 nowait = (LogStat & LOG_NOWAIT); 358 pid = forkx(nowait? 0 : (FORK_NOSIGCHLD | FORK_WAITPID)); 359 if (pid == -1) 360 return; 361 362 if (pid == 0) { 363 sigset_t sigs; 364 int fd; 365 366 (void) sigset(SIGALRM, SIG_DFL); 367 (void) sigemptyset(&sigs); 368 (void) sigaddset(&sigs, SIGALRM); 369 (void) sigprocmask(SIG_UNBLOCK, &sigs, NULL); 370 (void) alarm(5); 371 if (((fd = open(sysmsg, O_WRONLY)) >= 0) || 372 (fd = open(ctty, O_WRONLY)) >= 0) { 373 (void) alarm(0); 374 outline[clen - 1] = '\r'; 375 (void) write(fd, outline, clen); 376 (void) close(fd); 377 } 378 _exit(0); 379 } 380 if (!nowait) 381 while (waitpid(pid, NULL, 0) == -1 && errno == EINTR) 382 continue; 383 } 384 385 /* 386 * Use a door call to syslogd to see if it's alive. 387 */ 388 static int 389 syslogd_ok(void) 390 { 391 int d; 392 int s; 393 door_arg_t darg; 394 door_info_t info; 395 396 if ((d = open(DOORFILE, O_RDONLY)) < 0) 397 return (0); 398 /* 399 * see if our pid matches the pid of the door server. 400 * If so, syslogd has called syslog(), probably as 401 * a result of some name service library error, and 402 * we don't want to let syslog continue and possibly 403 * fork here. 404 */ 405 info.di_target = 0; 406 if (__door_info(d, &info) < 0 || info.di_target == getpid()) { 407 (void) close(d); 408 return (0); 409 } 410 darg.data_ptr = NULL; 411 darg.data_size = 0; 412 darg.desc_ptr = NULL; 413 darg.desc_num = 0; 414 darg.rbuf = NULL; 415 darg.rsize = 0; 416 s = __door_call(d, &darg); 417 (void) close(d); 418 if (s < 0) 419 return (0); /* failure - syslogd dead */ 420 else 421 return (1); 422 } 423 424 /* 425 * OPENLOG -- open system log 426 */ 427 428 void 429 openlog(const char *ident, int logstat, int logfac) 430 { 431 struct stat statbuff; 432 433 OpenLogCalled = 1; 434 if (ident != NULL) 435 LogTag = ident; 436 LogStat = logstat; 437 if (logfac != 0) 438 LogFacility = logfac & LOG_FACMASK; 439 440 /* 441 * if the fstat(2) fails or the st_rdev has changed 442 * then we must open the file 443 */ 444 if ((fstat(LogFile, &statbuff) == 0) && 445 (S_ISCHR(statbuff.st_mode)) && (statbuff.st_rdev == LogDev)) 446 return; 447 448 if (LogStat & LOG_NDELAY) { 449 LogFile = open(logname, O_WRONLY); 450 (void) fcntl(LogFile, F_SETFD, 1); 451 (void) fstat(LogFile, &statbuff); 452 LogDev = statbuff.st_rdev; 453 } 454 } 455 456 /* 457 * CLOSELOG -- close the system log 458 */ 459 460 void 461 closelog(void) 462 { 463 struct stat statbuff; 464 465 OpenLogCalled = 0; 466 467 /* if the LogFile is invalid it can not be closed */ 468 if (LogFileInvalid) 469 return; 470 471 /* 472 * if the fstat(2) fails or the st_rdev has changed 473 * then we can not close the file 474 */ 475 if ((fstat(LogFile, &statbuff) == 0) && (statbuff.st_rdev == LogDev)) { 476 (void) close(LogFile); 477 LogFile = -1; 478 LogStat = 0; 479 } 480 } 481 482 /* 483 * SETLOGMASK -- set the log mask level 484 */ 485 int 486 setlogmask(int pmask) 487 { 488 int omask = 0; 489 490 omask = LogMask; 491 if (pmask != 0) 492 LogMask = pmask; 493 return (omask); 494 } 495