diff options
Diffstat (limited to 'lib/libc/gen/syslog.c')
| -rw-r--r-- | lib/libc/gen/syslog.c | 496 |
1 files changed, 496 insertions, 0 deletions
diff --git a/lib/libc/gen/syslog.c b/lib/libc/gen/syslog.c new file mode 100644 index 000000000000..a6290ee81a29 --- /dev/null +++ b/lib/libc/gen/syslog.c @@ -0,0 +1,496 @@ +/*- + * 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 "namespace.h" +#include <sys/param.h> +#include <sys/socket.h> +#include <sys/syslog.h> +#include <sys/time.h> +#include <sys/uio.h> +#include <sys/un.h> +#include <netdb.h> + +#include <errno.h> +#include <fcntl.h> +#include <paths.h> +#include <pthread.h> +#include <stdbool.h> +#include <stdio.h> +#include <stdlib.h> +#include <string.h> +#include <time.h> +#include <unistd.h> + +#include <stdarg.h> +#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 bool connected; /* have done connect */ +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 */ + +/* + * 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(); + 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. + */ + if (LogTagLength <= 0) + 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() failed, there are two likely scenarios: + * 1) syslogd was restarted. In this case make one (only) attempt + * to reconnect. + * 2) We filled our buffer due to syslogd not being able to read + * as fast as we write. In this case prefer to lose the current + * message rather than whole buffer of previously logged data. + */ + if (send(LogFile, tbuf, cnt, 0) < 0) { + if (errno != ENOBUFS) { + disconnectlog(); + connectlog(); + 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; + } + connected = false; /* 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 (!connected) { + SyslogAddr.sun_len = sizeof(SyslogAddr); + SyslogAddr.sun_family = AF_UNIX; + + (void)strncpy(SyslogAddr.sun_path, _PATH_LOG, + sizeof SyslogAddr.sun_path); + if (_connect(LogFile, (struct sockaddr *)&SyslogAddr, + sizeof(SyslogAddr)) != -1) + connected = true; + else { + (void)_close(LogFile); + LogFile = -1; + } + } +} + +static void +openlog_unlocked(const char *ident, int logstat, int logfac) +{ + 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; + connected = false; + 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 per RFC 3164, + * Section 5.3 Originating Process Information: + * + * 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; +} |