1/*
2 * Copyright (c) 1983, 1988, 1993
3 * The Regents of the University of California. All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
13 * 4. Neither the name of the University nor the names of its contributors
14 * may be used to endorse or promote products derived from this software
15 * without specific prior written permission.
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27 * SUCH DAMAGE.
28 */
29
30#if defined(LIBC_SCCS) && !defined(lint)
31static char sccsid[] = "@(#)syslog.c 8.4 (Berkeley) 3/18/94";
32#endif /* LIBC_SCCS and not lint */
33
34#include <sys/types.h>
35#include <sys/socket.h>
36#include <sys/syslog.h>
37#include <sys/uio.h>
38#include <sys/un.h>
39#include <netdb.h>
40
41#include <errno.h>
42#include <fcntl.h>
43#include <paths.h>
44#include <stdio.h>
45#include <stdio_ext.h>
46#include <string.h>
47#include <time.h>
48#include <unistd.h>
49#include <stdlib.h>
50#include <libc-lock.h>
51#include <signal.h>
52#include <locale.h>
53
54#include <stdarg.h>
55
56#include <libio/libioP.h>
57#include <math_ldbl_opt.h>
58
59#include <kernel-features.h>
60
61#define ftell(s) _IO_ftell (s)
62
63static int LogType = SOCK_DGRAM; /* type of socket connection */
64static int LogFile = -1; /* fd for log */
65static bool connected; /* have done connect */
66static int LogStat; /* status bits, set by openlog() */
67static const char *LogTag; /* string to tag the entry with */
68static int LogFacility = LOG_USER; /* default facility code */
69static int LogMask = 0xff; /* mask of priorities to be logged */
70extern char *__progname; /* Program name, from crt0. */
71
72/* Define the lock. */
73__libc_lock_define_initialized (static, syslog_lock)
74
75static void openlog_internal(const char *, int, int);
76static void closelog_internal(void);
77
78struct cleanup_arg
79{
80 void *buf;
81 struct sigaction *oldaction;
82};
83
84static void
85cancel_handler (void *ptr)
86{
87 /* Restore the old signal handler. */
88 struct cleanup_arg *clarg = (struct cleanup_arg *) ptr;
89
90 if (clarg != NULL)
91 /* Free the memstream buffer, */
92 free (clarg->buf);
93
94 /* Free the lock. */
95 __libc_lock_unlock (syslog_lock);
96}
97
98
99/*
100 * syslog, vsyslog --
101 * print message on log file; output is intended for syslogd(8).
102 */
103void
104__syslog(int pri, const char *fmt, ...)
105{
106 va_list ap;
107
108 va_start(ap, fmt);
109 __vsyslog_internal(pri, fmt, ap, 0);
110 va_end(ap);
111}
112ldbl_hidden_def (__syslog, syslog)
113ldbl_strong_alias (__syslog, syslog)
114
115void
116__vsyslog(int pri, const char *fmt, va_list ap)
117{
118 __vsyslog_internal(pri, fmt, ap, 0);
119}
120ldbl_weak_alias (__vsyslog, vsyslog)
121
122void
123__syslog_chk(int pri, int flag, const char *fmt, ...)
124{
125 va_list ap;
126
127 va_start(ap, fmt);
128 __vsyslog_internal(pri, fmt, ap, (flag > 0) ? PRINTF_FORTIFY : 0);
129 va_end(ap);
130}
131
132void
133__vsyslog_chk(int pri, int flag, const char *fmt, va_list ap)
134{
135 __vsyslog_internal(pri, fmt, ap, (flag > 0) ? PRINTF_FORTIFY : 0);
136}
137
138void
139__vsyslog_internal(int pri, const char *fmt, va_list ap,
140 unsigned int mode_flags)
141{
142 struct tm now_tm;
143 time_t now;
144 int fd;
145 FILE *f;
146 char *buf = 0;
147 size_t bufsize = 0;
148 size_t msgoff;
149 int saved_errno = errno;
150 char failbuf[3 * sizeof (pid_t) + sizeof "out of memory []"];
151
152#define INTERNALLOG LOG_ERR|LOG_CONS|LOG_PERROR|LOG_PID
153 /* Check for invalid bits. */
154 if (pri & ~(LOG_PRIMASK|LOG_FACMASK)) {
155 syslog(INTERNALLOG,
156 "syslog: unknown facility/priority: %x", pri);
157 pri &= LOG_PRIMASK|LOG_FACMASK;
158 }
159
160 /* Prepare for multiple users. We have to take care: most
161 syscalls we are using are cancellation points. */
162 struct cleanup_arg clarg;
163 clarg.buf = NULL;
164 clarg.oldaction = NULL;
165 __libc_cleanup_push (cancel_handler, &clarg);
166 __libc_lock_lock (syslog_lock);
167
168 /* Check priority against setlogmask values. */
169 if ((LOG_MASK (LOG_PRI (pri)) & LogMask) == 0)
170 goto out;
171
172 /* Set default facility if none specified. */
173 if ((pri & LOG_FACMASK) == 0)
174 pri |= LogFacility;
175
176 /* Build the message in a memory-buffer stream. */
177 f = __open_memstream (&buf, &bufsize);
178 if (f == NULL)
179 {
180 /* We cannot get a stream. There is not much we can do but
181 emitting an error messages. */
182 char numbuf[3 * sizeof (pid_t)];
183 char *nump;
184 char *endp = __stpcpy (failbuf, "out of memory [");
185 pid_t pid = __getpid ();
186
187 nump = numbuf + sizeof (numbuf);
188 /* The PID can never be zero. */
189 do
190 *--nump = '0' + pid % 10;
191 while ((pid /= 10) != 0);
192
193 endp = __mempcpy (endp, nump, (numbuf + sizeof (numbuf)) - nump);
194 *endp++ = ']';
195 *endp = '\0';
196 buf = failbuf;
197 bufsize = endp - failbuf;
198 msgoff = 0;
199 }
200 else
201 {
202 __fsetlocking (f, FSETLOCKING_BYCALLER);
203 fprintf (f, "<%d>", pri);
204 now = time_now ();
205 f->_IO_write_ptr += __strftime_l (f->_IO_write_ptr,
206 f->_IO_write_end
207 - f->_IO_write_ptr,
208 "%h %e %T ",
209 __localtime_r (&now, &now_tm),
210 _nl_C_locobj_ptr);
211 msgoff = ftell (f);
212 if (LogTag == NULL)
213 LogTag = __progname;
214 if (LogTag != NULL)
215 __fputs_unlocked (LogTag, f);
216 if (LogStat & LOG_PID)
217 fprintf (f, "[%d]", (int) __getpid ());
218 if (LogTag != NULL)
219 {
220 __putc_unlocked (':', f);
221 __putc_unlocked (' ', f);
222 }
223
224 /* Restore errno for %m format. */
225 __set_errno (saved_errno);
226
227 /* We have the header. Print the user's format into the
228 buffer. */
229 __vfprintf_internal (f, fmt, ap, mode_flags);
230
231 /* Close the memory stream; this will finalize the data
232 into a malloc'd buffer in BUF. */
233 fclose (f);
234
235 /* Tell the cancellation handler to free this buffer. */
236 clarg.buf = buf;
237 }
238
239 /* Output to stderr if requested. */
240 if (LogStat & LOG_PERROR) {
241 struct iovec iov[2];
242 struct iovec *v = iov;
243
244 v->iov_base = buf + msgoff;
245 v->iov_len = bufsize - msgoff;
246 /* Append a newline if necessary. */
247 if (buf[bufsize - 1] != '\n')
248 {
249 ++v;
250 v->iov_base = (char *) "\n";
251 v->iov_len = 1;
252 }
253
254 /* writev is a cancellation point. */
255 (void)__writev(STDERR_FILENO, iov, v - iov + 1);
256 }
257
258 /* Get connected, output the message to the local logger. */
259 if (!connected)
260 openlog_internal(NULL, LogStat | LOG_NDELAY, LogFacility);
261
262 /* If we have a SOCK_STREAM connection, also send ASCII NUL as
263 a record terminator. */
264 if (LogType == SOCK_STREAM)
265 ++bufsize;
266
267 if (!connected || __send(LogFile, buf, bufsize, MSG_NOSIGNAL) < 0)
268 {
269 if (connected)
270 {
271 /* Try to reopen the syslog connection. Maybe it went
272 down. */
273 closelog_internal ();
274 openlog_internal(NULL, LogStat | LOG_NDELAY, LogFacility);
275 }
276
277 if (!connected || __send(LogFile, buf, bufsize, MSG_NOSIGNAL) < 0)
278 {
279 closelog_internal (); /* attempt re-open next time */
280 /*
281 * Output the message to the console; don't worry
282 * about blocking, if console blocks everything will.
283 * Make sure the error reported is the one from the
284 * syslogd failure.
285 */
286 if (LogStat & LOG_CONS &&
287 (fd = __open(_PATH_CONSOLE, O_WRONLY|O_NOCTTY|O_CLOEXEC,
288 0)) >= 0)
289 {
290 __dprintf (fd, "%s\r\n", buf + msgoff);
291 (void)__close(fd);
292 }
293 }
294 }
295
296 out:
297 /* End of critical section. */
298 __libc_cleanup_pop (0);
299 __libc_lock_unlock (syslog_lock);
300
301 if (buf != failbuf)
302 free (buf);
303}
304
305/* AF_UNIX address of local logger */
306static const struct sockaddr_un SyslogAddr =
307 {
308 .sun_family = AF_UNIX,
309 .sun_path = _PATH_LOG
310 };
311
312static void
313openlog_internal(const char *ident, int logstat, int logfac)
314{
315 if (ident != NULL)
316 LogTag = ident;
317 LogStat = logstat;
318 if ((logfac &~ LOG_FACMASK) == 0)
319 LogFacility = logfac;
320
321 int retry = 0;
322 while (retry < 2) {
323 if (LogFile == -1) {
324 if (LogStat & LOG_NDELAY) {
325 LogFile = __socket(AF_UNIX, LogType | SOCK_CLOEXEC, 0);
326 if (LogFile == -1)
327 return;
328 }
329 }
330 if (LogFile != -1 && !connected)
331 {
332 int old_errno = errno;
333 if (__connect(LogFile, &SyslogAddr, sizeof(SyslogAddr))
334 == -1)
335 {
336 int saved_errno = errno;
337 int fd = LogFile;
338 LogFile = -1;
339 (void)__close(fd);
340 __set_errno (old_errno);
341 if (saved_errno == EPROTOTYPE)
342 {
343 /* retry with the other type: */
344 LogType = (LogType == SOCK_DGRAM
345 ? SOCK_STREAM : SOCK_DGRAM);
346 ++retry;
347 continue;
348 }
349 } else
350 connected = true;
351 }
352 break;
353 }
354}
355
356void
357openlog (const char *ident, int logstat, int logfac)
358{
359 /* Protect against multiple users and cancellation. */
360 __libc_cleanup_push (cancel_handler, NULL);
361 __libc_lock_lock (syslog_lock);
362
363 openlog_internal (ident, logstat, logfac);
364
365 __libc_cleanup_pop (1);
366}
367
368static void
369closelog_internal (void)
370{
371 if (!connected)
372 return;
373
374 __close (LogFile);
375 LogFile = -1;
376 connected = false;
377}
378
379void
380closelog (void)
381{
382 /* Protect against multiple users and cancellation. */
383 __libc_cleanup_push (cancel_handler, NULL);
384 __libc_lock_lock (syslog_lock);
385
386 closelog_internal ();
387 LogTag = NULL;
388 LogType = SOCK_DGRAM; /* this is the default */
389
390 /* Free the lock. */
391 __libc_cleanup_pop (1);
392}
393
394/* setlogmask -- set the log mask level */
395int
396setlogmask (int pmask)
397{
398 int omask;
399
400 /* Protect against multiple users. */
401 __libc_lock_lock (syslog_lock);
402
403 omask = LogMask;
404 if (pmask != 0)
405 LogMask = pmask;
406
407 __libc_lock_unlock (syslog_lock);
408
409 return (omask);
410}
411