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