diff --git a/lib/libc/gen/syslog.c b/lib/libc/gen/syslog.c index 797c7389d1a2..fe3a2c902015 100644 --- a/lib/libc/gen/syslog.c +++ b/lib/libc/gen/syslog.c @@ -1,508 +1,556 @@ /*- * SPDX-License-Identifier: BSD-3-Clause * * Copyright (c) 1983, 1988, 1993 * The Regents of the University of California. All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * 3. Neither the name of the University nor the names of its contributors * may be used to endorse or promote products derived from this software * without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. */ #include __SCCSID("@(#)syslog.c 8.5 (Berkeley) 4/29/95"); __FBSDID("$FreeBSD$"); #include "namespace.h" #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include "un-namespace.h" #include "libc_private.h" /* Maximum number of characters of syslog message */ #define MAXLINE 8192 static int LogFile = -1; /* fd for log */ static int status; /* connection status */ static int opened; /* have done openlog() */ static int LogStat = 0; /* status bits, set by openlog() */ +static pid_t LogPid = -1; /* process id to tag the entry with */ static const char *LogTag = NULL; /* string to tag the entry with */ +static int LogTagLength = -1; /* usable part of LogTag */ static int LogFacility = LOG_USER; /* default facility code */ static int LogMask = 0xff; /* mask of priorities to be logged */ static pthread_mutex_t syslog_mutex = PTHREAD_MUTEX_INITIALIZER; #define THREAD_LOCK() \ do { \ if (__isthreaded) _pthread_mutex_lock(&syslog_mutex); \ } while(0) #define THREAD_UNLOCK() \ do { \ if (__isthreaded) _pthread_mutex_unlock(&syslog_mutex); \ } while(0) /* RFC5424 defined value. */ #define NILVALUE "-" static void disconnectlog(void); /* disconnect from syslogd */ static void connectlog(void); /* (re)connect to syslogd */ static void openlog_unlocked(const char *, int, int); +static void parse_tag(void); /* parse ident[NNN] if needed */ enum { NOCONN = 0, CONNDEF, CONNPRIV, }; /* * Format of the magic cookie passed through the stdio hook */ struct bufcookie { char *base; /* start of buffer */ int left; }; /* * stdio write hook for writing to a static string buffer * XXX: Maybe one day, dynamically allocate it so that the line length * is `unlimited'. */ static int writehook(void *cookie, const char *buf, int len) { struct bufcookie *h; /* private `handle' */ h = (struct bufcookie *)cookie; if (len > h->left) { /* clip in case of wraparound */ len = h->left; } if (len > 0) { (void)memcpy(h->base, buf, len); /* `write' it. */ h->base += len; h->left -= len; } return len; } /* * syslog, vsyslog -- * print message on log file; output is intended for syslogd(8). */ void syslog(int pri, const char *fmt, ...) { va_list ap; va_start(ap, fmt); vsyslog(pri, fmt, ap); va_end(ap); } static void vsyslog1(int pri, const char *fmt, va_list ap) { struct timeval now; struct tm tm; char ch, *p; long tz_offset; int cnt, fd, saved_errno; char hostname[MAXHOSTNAMELEN], *stdp, tbuf[MAXLINE], fmt_cpy[MAXLINE], errstr[64], tz_sign; FILE *fp, *fmt_fp; struct bufcookie tbuf_cookie; struct bufcookie fmt_cookie; #define INTERNALLOG LOG_ERR|LOG_CONS|LOG_PERROR|LOG_PID /* Check for invalid bits. */ if (pri & ~(LOG_PRIMASK|LOG_FACMASK)) { syslog(INTERNALLOG, "syslog: unknown facility/priority: %x", pri); pri &= LOG_PRIMASK|LOG_FACMASK; } saved_errno = errno; /* Check priority against setlogmask values. */ if (!(LOG_MASK(LOG_PRI(pri)) & LogMask)) return; /* Set default facility if none specified. */ if ((pri & LOG_FACMASK) == 0) pri |= LogFacility; /* Create the primary stdio hook */ tbuf_cookie.base = tbuf; tbuf_cookie.left = sizeof(tbuf); fp = fwopen(&tbuf_cookie, writehook); if (fp == NULL) return; /* Build the message according to RFC 5424. Tag and version. */ (void)fprintf(fp, "<%d>1 ", pri); /* Timestamp similar to RFC 3339. */ if (gettimeofday(&now, NULL) == 0 && localtime_r(&now.tv_sec, &tm) != NULL) { if (tm.tm_gmtoff < 0) { tz_sign = '-'; tz_offset = -tm.tm_gmtoff; } else { tz_sign = '+'; tz_offset = tm.tm_gmtoff; } (void)fprintf(fp, "%04d-%02d-%02d" /* Date. */ "T%02d:%02d:%02d.%06ld" /* Time. */ "%c%02ld:%02ld ", /* Time zone offset. */ tm.tm_year + 1900, tm.tm_mon + 1, tm.tm_mday, tm.tm_hour, tm.tm_min, tm.tm_sec, now.tv_usec, tz_sign, tz_offset / 3600, (tz_offset % 3600) / 60); } else (void)fputs(NILVALUE " ", fp); /* Hostname. */ (void)gethostname(hostname, sizeof(hostname)); (void)fprintf(fp, "%s ", hostname[0] == '\0' ? NILVALUE : hostname); if (LogStat & LOG_PERROR) { /* Transfer to string buffer */ (void)fflush(fp); stdp = tbuf + (sizeof(tbuf) - tbuf_cookie.left); } /* Application name. */ if (LogTag == NULL) LogTag = _getprogname(); - (void)fprintf(fp, "%s ", LogTag == NULL ? NILVALUE : LogTag); + else if (LogTagLength == -1) + parse_tag(); + if (LogTagLength > 0) + (void)fprintf(fp, "%.*s ", LogTagLength, LogTag); + else + (void)fprintf(fp, "%s ", LogTag == NULL ? NILVALUE : LogTag); /* * Provide the process ID regardless of whether LOG_PID has been * specified, as it provides valuable information. Many * applications tend not to use this, even though they should. */ - (void)fprintf(fp, "%d ", getpid()); + if (LogPid == -1) + LogPid = getpid(); + (void)fprintf(fp, "%d ", (int)LogPid); /* Message ID. */ (void)fputs(NILVALUE " ", fp); /* Structured data. */ (void)fputs(NILVALUE " ", fp); /* Check to see if we can skip expanding the %m */ if (strstr(fmt, "%m")) { /* Create the second stdio hook */ fmt_cookie.base = fmt_cpy; fmt_cookie.left = sizeof(fmt_cpy) - 1; fmt_fp = fwopen(&fmt_cookie, writehook); if (fmt_fp == NULL) { fclose(fp); return; } /* * Substitute error message for %m. Be careful not to * molest an escaped percent "%%m". We want to pass it * on untouched as the format is later parsed by vfprintf. */ for ( ; (ch = *fmt); ++fmt) { if (ch == '%' && fmt[1] == 'm') { ++fmt; strerror_r(saved_errno, errstr, sizeof(errstr)); fputs(errstr, fmt_fp); } else if (ch == '%' && fmt[1] == '%') { ++fmt; fputc(ch, fmt_fp); fputc(ch, fmt_fp); } else { fputc(ch, fmt_fp); } } /* Null terminate if room */ fputc(0, fmt_fp); fclose(fmt_fp); /* Guarantee null termination */ fmt_cpy[sizeof(fmt_cpy) - 1] = '\0'; fmt = fmt_cpy; } /* Message. */ (void)vfprintf(fp, fmt, ap); (void)fclose(fp); cnt = sizeof(tbuf) - tbuf_cookie.left; /* Remove a trailing newline */ if (tbuf[cnt - 1] == '\n') cnt--; /* Output to stderr if requested. */ if (LogStat & LOG_PERROR) { struct iovec iov[2]; struct iovec *v = iov; v->iov_base = stdp; v->iov_len = cnt - (stdp - tbuf); ++v; v->iov_base = "\n"; v->iov_len = 1; (void)_writev(STDERR_FILENO, iov, 2); } /* Get connected, output the message to the local logger. */ if (!opened) openlog_unlocked(LogTag, LogStat | LOG_NDELAY, 0); connectlog(); /* * If the send() fails, there are two likely scenarios: * 1) syslogd was restarted * 2) /var/run/log is out of socket buffer space, which * in most cases means local DoS. * If the error does not indicate a full buffer, we address * case #1 by attempting to reconnect to /var/run/log[priv] * and resending the message once. * * If we are working with a privileged socket, the retry * attempts end there, because we don't want to freeze a * critical application like su(1) or sshd(8). * * Otherwise, we address case #2 by repeatedly retrying the * send() to give syslogd a chance to empty its socket buffer. */ if (send(LogFile, tbuf, cnt, 0) < 0) { if (errno != ENOBUFS) { /* * Scenario 1: syslogd was restarted * reconnect and resend once */ disconnectlog(); connectlog(); if (send(LogFile, tbuf, cnt, 0) >= 0) return; /* * if the resend failed, fall through to * possible scenario 2 */ } while (errno == ENOBUFS) { /* * Scenario 2: out of socket buffer space * possible DoS, fail fast on a privileged * socket */ if (status == CONNPRIV) break; _usleep(1); if (send(LogFile, tbuf, cnt, 0) >= 0) return; } } else return; /* * Output the message to the console; try not to block * as a blocking console should not stop other processes. * Make sure the error reported is the one from the syslogd failure. */ if (LogStat & LOG_CONS && (fd = _open(_PATH_CONSOLE, O_WRONLY|O_NONBLOCK|O_CLOEXEC, 0)) >= 0) { struct iovec iov[2]; struct iovec *v = iov; p = strchr(tbuf, '>') + 3; v->iov_base = p; v->iov_len = cnt - (p - tbuf); ++v; v->iov_base = "\r\n"; v->iov_len = 2; (void)_writev(fd, iov, 2); (void)_close(fd); } } static void syslog_cancel_cleanup(void *arg __unused) { THREAD_UNLOCK(); } void vsyslog(int pri, const char *fmt, va_list ap) { THREAD_LOCK(); pthread_cleanup_push(syslog_cancel_cleanup, NULL); vsyslog1(pri, fmt, ap); pthread_cleanup_pop(1); } /* Should be called with mutex acquired */ static void disconnectlog(void) { /* * If the user closed the FD and opened another in the same slot, * that's their problem. They should close it before calling on * system services. */ if (LogFile != -1) { _close(LogFile); LogFile = -1; } status = NOCONN; /* retry connect */ } /* Should be called with mutex acquired */ static void connectlog(void) { struct sockaddr_un SyslogAddr; /* AF_UNIX address of local logger */ if (LogFile == -1) { socklen_t len; if ((LogFile = _socket(AF_UNIX, SOCK_DGRAM | SOCK_CLOEXEC, 0)) == -1) return; if (_getsockopt(LogFile, SOL_SOCKET, SO_SNDBUF, &len, &(socklen_t){sizeof(len)}) == 0) { if (len < MAXLINE) { len = MAXLINE; (void)_setsockopt(LogFile, SOL_SOCKET, SO_SNDBUF, &len, sizeof(len)); } } } if (LogFile != -1 && status == NOCONN) { SyslogAddr.sun_len = sizeof(SyslogAddr); SyslogAddr.sun_family = AF_UNIX; /* * First try privileged socket. If no success, * then try default socket. */ (void)strncpy(SyslogAddr.sun_path, _PATH_LOG_PRIV, sizeof SyslogAddr.sun_path); if (_connect(LogFile, (struct sockaddr *)&SyslogAddr, sizeof(SyslogAddr)) != -1) status = CONNPRIV; if (status == NOCONN) { (void)strncpy(SyslogAddr.sun_path, _PATH_LOG, sizeof SyslogAddr.sun_path); if (_connect(LogFile, (struct sockaddr *)&SyslogAddr, sizeof(SyslogAddr)) != -1) status = CONNDEF; } if (status == NOCONN) { /* * Try the old "/dev/log" path, for backward * compatibility. */ (void)strncpy(SyslogAddr.sun_path, _PATH_OLDLOG, sizeof SyslogAddr.sun_path); if (_connect(LogFile, (struct sockaddr *)&SyslogAddr, sizeof(SyslogAddr)) != -1) status = CONNDEF; } if (status == NOCONN) { (void)_close(LogFile); LogFile = -1; } } } static void openlog_unlocked(const char *ident, int logstat, int logfac) { - if (ident != NULL) + if (ident != NULL) { LogTag = ident; + LogTagLength = -1; + } LogStat = logstat; + parse_tag(); if (logfac != 0 && (logfac &~ LOG_FACMASK) == 0) LogFacility = logfac; if (LogStat & LOG_NDELAY) /* open immediately */ connectlog(); opened = 1; /* ident and facility has been set */ } void openlog(const char *ident, int logstat, int logfac) { THREAD_LOCK(); pthread_cleanup_push(syslog_cancel_cleanup, NULL); openlog_unlocked(ident, logstat, logfac); pthread_cleanup_pop(1); } void closelog(void) { THREAD_LOCK(); if (LogFile != -1) { (void)_close(LogFile); LogFile = -1; } LogTag = NULL; + LogTagLength = -1; status = NOCONN; THREAD_UNLOCK(); } /* setlogmask -- set the log mask level */ int setlogmask(int pmask) { int omask; THREAD_LOCK(); omask = LogMask; if (pmask != 0) LogMask = pmask; THREAD_UNLOCK(); return (omask); } + +/* + * Obtain LogPid from LogTag formatted as following: ident[NNN] + */ +static void +parse_tag(void) +{ + char *begin, *end, *p; + pid_t pid; + + if (LogTag == NULL || (LogStat & LOG_PID) != 0) + return; + /* + * LogTagLength is -1 if LogTag was not parsed yet. + * Avoid multiple passes over same LogTag. + */ + LogTagLength = 0; + + /* Check for presence of opening [ and non-empty ident. */ + if ((begin = strchr(LogTag, '[')) == NULL || begin == LogTag) + return; + /* Check for presence of closing ] at the very end and non-empty pid. */ + if ((end = strchr(begin + 1, ']')) == NULL || end[1] != 0 || + (end - begin) < 2) + return; + + /* Check for pid to contain digits only. */ + pid = (pid_t)strtol(begin + 1, &p, 10); + if (p != end) + return; + + LogPid = pid; + LogTagLength = begin - LogTag; +}