2 * Copyright (c) 1983, 1988, 1993
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15 * This product includes software developed by the University of
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35 * SYSLOG -- print message on log file
37 * This routine looks a lot like printf, except that it outputs to the
38 * log file instead of the standard output. Also:
40 * prints the module name in front of the message,
41 * has some other formatting types (or will sometime),
42 * adds a newline on the end of the message.
44 * The output of this routine is intended to be read by syslogd(8).
47 * Modified to use UNIX domain IPC by Ralph Campbell
48 * Patched March 12, 1996 by A. Ian Vogelesang <vogelesang@hdshq.com>
49 * - to correct the handling of message & format string truncation,
50 * - to visibly tag truncated records to facilitate
51 * investigation of such Bad Things with grep, and,
52 * - to correct the handling of case where "write"
53 * returns after writing only part of the message.
54 * Rewritten by Martin Mares <mj@atrey.karlin.mff.cuni.cz> on May 14, 1997
55 * - better buffer overrun checks.
56 * - special handling of "%m" removed as we use GNU sprintf which handles
58 * - Major code cleanup.
63 #include <sys/types.h>
64 #include <sys/socket.h>
66 #include <sys/signal.h>
67 #include <sys/syslog.h>
84 #include <bits/uClibc_mutex.h>
85 __UCLIBC_MUTEX_STATIC(mylock, PTHREAD_RECURSIVE_MUTEX_INITIALIZER_NP);
88 static int LogFile = -1; /* fd for log */
89 static smalluint connected; /* have done connect */
90 /* all bits in option argument for openlog() fit in 8 bits */
91 static smalluint LogStat = 0; /* status bits, set by openlog() */
92 static const char *LogTag = "syslog"; /* string to tag the entry with */
93 /* this fits in 8 bits too (LOG_LOCAL7 = 23<<3 = 184),
94 * but NB: LOG_FACMASK is bigger (= 0x03f8 = 127<<3) for some strange reason.
96 static int LogFacility = LOG_USER;/* default facility code */
97 /* bits mask of priorities (eight prios - 8 bits is enough) */
98 static smalluint LogMask = 0xff; /* mask of priorities to be logged */
99 /* AF_UNIX address of local logger (we use struct sockaddr
100 * instead of struct sockaddr_un since "/dev/log" is small enough) */
101 static const struct sockaddr SyslogAddr = {
102 .sa_family = AF_UNIX, /* sa_family_t (usually a short) */
103 .sa_data = _PATH_LOG /* char [14] */
107 closelog_intern(int sig)
109 /* mylock must be held by the caller */
111 (void) close(LogFile);
115 if (sig == 0) { /* called from closelog()? - reset to defaults */
118 LogFacility = LOG_USER;
124 * OPENLOG -- open system log
127 openlog(const char *ident, int logstat, int logfac)
129 int logType = SOCK_DGRAM;
131 __UCLIBC_MUTEX_LOCK(mylock);
136 if (logfac != 0 && (logfac &~ LOG_FACMASK) == 0)
137 LogFacility = logfac;
140 if (LogStat & LOG_NDELAY) {
141 if ((LogFile = socket(AF_UNIX, logType, 0)) == -1) {
144 fcntl(LogFile, F_SETFD, FD_CLOEXEC);
145 /* We don't want to block if e.g. syslogd is SIGSTOPed */
146 fcntl(LogFile, F_SETFL, O_NONBLOCK | fcntl(LogFile, F_GETFL));
150 if (LogFile != -1 && !connected) {
151 if (connect(LogFile, &SyslogAddr, sizeof(SyslogAddr)) != -1) {
158 if (logType == SOCK_DGRAM) {
159 logType = SOCK_STREAM;
166 __UCLIBC_MUTEX_UNLOCK(mylock);
168 libc_hidden_def(openlog)
172 * print message on log file; output is intended for syslogd(8).
175 vsyslog(int pri, const char *fmt, va_list ap)
178 char *last_chr, *head_end, *end, *stdp;
182 char tbuf[1024]; /* syslogd is unable to handle longer messages */
183 struct sigaction action, oldaction;
185 memset(&action, 0, sizeof(action));
186 action.sa_handler = closelog_intern;
187 sigaction(SIGPIPE, &action, &oldaction);
191 __UCLIBC_MUTEX_LOCK(mylock);
193 /* See if we should just throw out this message. */
194 if (!(LogMask & LOG_MASK(LOG_PRI(pri))) || (pri &~ (LOG_PRIMASK|LOG_FACMASK)))
196 if (LogFile < 0 || !connected)
197 openlog(LogTag, LogStat | LOG_NDELAY, 0);
199 /* Set default facility if none specified. */
200 if ((pri & LOG_FACMASK) == 0)
203 /* Build the message. We know the starting part of the message can take
204 * no longer than 64 characters plus length of the LogTag. So it's
205 * safe to test only LogTag and use normal sprintf everywhere else.
208 stdp = p = tbuf + sprintf(tbuf, "<%d>%.15s ", pri, ctime(&now) + 4);
210 if (strlen(LogTag) < sizeof(tbuf) - 64)
211 p += sprintf(p, "%s", LogTag);
213 p += sprintf(p, "<BUFFER OVERRUN ATTEMPT>");
215 if (LogStat & LOG_PID)
216 p += sprintf(p, "[%d]", getpid());
223 /* We format the rest of the message. If the buffer becomes full, we mark
224 * the message as truncated. Note that we require at least 2 free bytes
225 * in the buffer as we might want to add "\r\n" there.
228 end = tbuf + sizeof(tbuf) - 1;
229 __set_errno(saved_errno);
230 p += vsnprintf(p, end - p, fmt, ap);
231 if (p >= end || p < head_end) { /* Returned -1 in case of error... */
232 static const char truncate_msg[12] = "[truncated] "; /* no NUL! */
233 memmove(head_end + sizeof(truncate_msg), head_end,
234 end - head_end - sizeof(truncate_msg));
235 memcpy(head_end, truncate_msg, sizeof(truncate_msg));
237 while (p < end && *p) {
248 /* Output to stderr if requested. */
249 if (LogStat & LOG_PERROR) {
251 (void)write(STDERR_FILENO, stdp, last_chr - stdp + 1);
254 /* Output the message to the local logger using NUL as a message delimiter. */
259 rc = write(LogFile, p, last_chr + 1 - p);
261 /* I don't think looping forever on EAGAIN is a good idea.
262 * Imagine that syslogd is SIGSTOPed... */
263 if (/* (errno != EAGAIN) && */ (errno != EINTR)) {
264 closelog_intern(1); /* 1: do not reset LogXXX globals to default */
270 } while (p <= last_chr);
276 * Output the message to the console; don't worry about blocking,
277 * if console blocks everything will. Make sure the error reported
278 * is the one from the syslogd failure.
280 /* should mode be O_WRONLY | O_NOCTTY? -- Uli */
281 /* yes, but in Linux "/dev/console" never becomes ctty anyway -- vda */
282 if ((LogStat & LOG_CONS) &&
283 (fd = open(_PATH_CONSOLE, O_WRONLY | O_NOCTTY)) >= 0) {
284 p = strchr(tbuf, '>') + 1;
287 (void)write(fd, p, last_chr - p + 2);
292 __UCLIBC_MUTEX_UNLOCK(mylock);
293 sigaction(SIGPIPE, &oldaction, NULL);
295 libc_hidden_def(vsyslog)
298 syslog(int pri, const char *fmt, ...)
303 vsyslog(pri, fmt, ap);
306 libc_hidden_def(syslog)
309 * CLOSELOG -- close the system log
314 __UCLIBC_MUTEX_LOCK(mylock);
315 closelog_intern(0); /* 0: reset LogXXX globals to default */
316 __UCLIBC_MUTEX_UNLOCK(mylock);
318 libc_hidden_def(closelog)
320 /* setlogmask -- set the log mask level */
321 int setlogmask(int pmask)
327 __UCLIBC_MUTEX_LOCK(mylock);
329 __UCLIBC_MUTEX_UNLOCK(mylock);